JP2003143177A - Atm communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ATM (asynchronous transfer mode) communication system for realizing communication between ATM nets without sacrificing high speed, large capacity and connection oriented property. SOLUTION: The ATM communication system is provided with an inter-net connection device for performing Internet working between ATM nets to be operated in an asynchronous transfer mode and a datagram server. When an address resolution target node for an ARP (address resolution protocol) request from an ATM net connected to the inter-net connection device itself does not exist in an ATM net connected to the connection device itself, the connection device performs ARP reply to the ARP request by replying the ATM address of ATM connection connected to the device itself, connects a first ATM connection indicated by the ATM address replied by the ARP reply to a second ATM connection set between the inter-net connection device and the datagram server, so that the transmission terminal of the datagram is directly connected to the datagram server by the ATM connection.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ATM communication system.

[0002]

2. Description of the Related Art In recent years, various communication demands such as image communication and high-speed data communication have been increasing, and in order to provide efficient and flexible communication services, the communication network is integrated (B-ISD).
N) is desired. ATM (Asyn
chronous Transfer Mode: Asynchronous Transfer Mode is a promising exchange. The ATM exchange method is to realize a communication service by storing information in a fixed-length packet called a cell regardless of its attribute and using this cell as a unit of exchange.

CCITT defines this ATM switching system as a formal next-generation switching system, and has decided to formally implement B-ISDN using the ATM switching system. Along with this, public networks and corporate networks are built on the basis of the ATM switching system, which is likely to meet the needs of next-generation multimedia communication and broadband communication.

There is a movement to apply this ATM switching system to the field of LAN (local area network). This is to realize a conventional LAN communication system represented by Ethernet (registered trademark) by an ATM switching system (hereinafter also referred to as an ATM communication system), and standardization has already started in the United States and the like.

When the ATM exchange system is applied to a LAN,
The following advantages can be considered.

(1) The communication speed of Ethernet, which can be said to be a substantial standard of the current LAN capable of realizing wide band communication, is 10 Mbps. FDDI (100 Mbps)
Higher speed LANs are emerging, but they are both shared media (a system in which all terminals share the band). In contrast, 150 Mbps / 620M
Since the introduction of the ATM switching system with bps as a standard is basically a star type configuration, the band can be exclusively used by the terminal, which may dramatically improve the throughput of the LAN. .

(2) In the current LAN suitable for multimedia, so-called data communication such as file transfer and transaction processing has been supported. Due to the method, real-time communication represented by voice and image is supported. Cannot be done, or even if it can be done, the overhead is very heavy and the supported bandwidth is very small.

On the other hand, the ATM exchange system has a real-time / continuous communication such as voice / image, and a non-continuous communication such as data communication due to unified processing by hardware and dramatic improvement of network reliability. It is a communication method that enables communication, that is, multimedia communication. From this, there is a possibility that the introduction of the ATM switching system into the LAN will promote the realization of a multimedia environment in the LAN.

(3) Good compatibility with the public network.

As described above, since CCITT has determined that the target for realizing broadband communication in the public network is the ATM switching system, the future public network (public communication network) will be constructed as an ATM network. Very likely to be done.

In addition to this, recently, there is an increasing demand for using the LAN environment in a wider area. This is to expand the same environment as LAN, that is, MAN (Metropolitan Area Network) and WAN (Wide).
It shows the growing need for Area Network). In order to realize this, it is necessary to interconnect terminals or LANs via a public network. Generally, when these terminals or networks are physically separated, they are interconnected via a public network. There is a need.

The ATM switching system is used in the public network, and LA
If a similar communication method is used in N as well, it is considered that information / packets can be interleaved at the boundary point by only simple protocol conversion.
It shows a high level of affinity with the public network. From these facts, it is considered that applying the ATM switching method to a LAN can secure a broadband communication line between a long-distance terminal / network and a real-time property, which has not been possible with a public network up to now. It can be said to promote the deployment of LAN to MAN or WAN.

On the other hand, in a conventional LAN environment such as Ethernet, when connecting LANs, that is, internetworking between LANs, a router is arranged between the LANs. This router is layer 3 (network layer) of the OSI protocol layer stack
The main function is the routing processing of datagram communication across LANs. That is,
A datagram that crosses two LANs is always raised to layer 3 by the router, where the destination network layer address is analyzed and delivered to the destination LAN according to the analysis result. This router is often called a "gateway" in the computer communication world, but the term "gateway" is defined as the entity that performs processing up to layer 7 in OSI. Since they are different, they will be unified by the term router hereinafter.

A "bridge" is also known as a device similar to a router for realizing a connection between LANs. This is because the router analyzes the destination network layer address and determines the LAN to send, while the bridge analyzes the data link layer address (MAC address) and sends the LAN.
Has been decided. Specifically, the bridge analyzes the destination MAC address of the received datagram and
When the AC address is not addressed to the own LAN, the datagram is transmitted to the other LAN to realize inter-LAN connection. Further, similar to this, "Bruta" is known that functions as a router for a certain fixed network layer protocol and as a bridge for other protocols.

Workstations (WS) have been commonly used for these routers, bridges and brutas. That is, the CPU in the WS analyzes the address and sends it to the assigned physical port to realize the functions of the router, bridge, and brouter.

[0016]

The ATM communication system is based on A
One of the features is to achieve high speed by hardware switching of TM cells. That is, A
TM network is "Connection Oriented" (hereinafter CO
It is also a network, and a virtual connection (Virtual Connection: VC) or a virtual path (also called Virtual Path: VP) is established between end-to-end, and these VCs or VPs are label-multiplexed with their identifiers (VCI or VPI). Alternatively, packets called cells are delivered end-to-end in a form of label exchange.

Information (data) delivered from end to end is stored in the payload of the ATM cell, and the ATM cell is exchanged to the destination terminal by hardware switching only along the VC / VP without software intervention. -Transferred. The hardware switching is performed by VPI / VCI (in some cases, ATM) included in the ATM cell header.
This is performed by the ATM switch by referring to the value of the other area of the cell header, such as PT.

When this ATM communication system is applied to the field of LAN, communication between terminals in the LAN is performed as described above.
It is considered that this can be achieved by communication through TM-VC / ATM-VP, and it can be expected that the communication speed between terminals increases dramatically.

However, when communication is carried out between LANs (hereinafter referred to as ATM-LANs) to which such an ATM communication system is applied, as described above, the routers, bridges or brutas located between the LANs compulsorily perform layering. Terminating at 3 or layer 2. There is a high possibility that the layer 2 and layer 3 processing after this termination is usually performed by software processing. For this reason, communication over LANs is significantly faster than communication within LANs.
Large capacity is likely to be lost. Further, in the conventional method of arranging routers, bridges, brouters, etc. between LANs to perform communication between LANs, it is basically impossible to extend VP / VC across LANs. VP
This is because / VC does not perform layer processing beyond the ATM layer between the endpoints. This is AT
For communication across M networks, this means that a connection-oriented communication line, which is one of the features of the ATM communication system, cannot be set.

In contrast to the ATM communication system, which is a connection-oriented communication system, the communication system used in the conventional data communication is "connectionless" (hereinafter CL
Also called). In the connectionless communication method, a connection is not necessarily established between end-to-end, the packet is sent to the network with the destination information attached to a part of the packet, and some node in the network analyzes the destination information and performs routing processing. Then, the packet is transferred to the destination terminal. That is, in connectionless communication, a terminal implements communication as a datagram without performing a connection setting procedure. A packet sent to the destination terminal in a connectionless manner in this way is called a datagram, and a communication method using this is a datagram. It is called the transfer method. In other words, connectionless communication is a method in which communication is realized in the form of datagram transfer without the terminal performing a connection setting procedure.

Most existing data terminals, such as workstations (WS) and personal computers (PC), apply this datagram transfer method. This is because most conventional LANs support the datagram transfer method, and the software (eg, OS) installed in the data terminal is for datagram transfer. Typical examples thereof include TCP / IP and UDP / IP.

These existing terminals or terminals equipped with existing protocols, that is, datagrams are generated,
In the terminal which sends to the other side terminal / network through the ATM network,
The datagram transfer method is used for communication between terminals.
Therefore, in order to adapt these terminals to the ATM network, (a) the current LAN board in the terminal, for example, an Ethernet board is used as the ATM network board (ATM board).
, Or the function of adapting to the interface with ATM-LAN using a terminal adapter (TA), (b) the function of putting a datagram in an ATM cell in some form at the terminal, (c) the data at the network It is necessary to improve the terminal side and the network by providing a function to deliver the gram to the destination terminal indicated by the destination address.
The term "terminal" here also includes a gateway between an existing LAN and an ATM network.

As a function for realizing this, the conventional CLSF is used.
A datagram delivery method using (connectionless service function) has been known. This datagram delivery method using CLSF is realized as follows.

A CLSF processing unit is arranged in the ATM network, and all datagrams are collected here. That is, all the datagram terminals and the CLSF processing unit are connected by PVC (Permanent VC) (VC, VP, or PVP may be used), and the terminal converts all the datagrams to be transmitted into ATM cells and C
It is placed on the PVC heading to the LSF processing unit and sent to the CLSF processing unit. The CLSF processing unit reproduces the received datagram, analyzes the destination address, selects the PVC connected to the destination address, re-assembles the datagram into ATM cells, and sends the ATM cells. When the PVC connected to the destination address does not exist, it is considered that the terminal which is the destination address is included when there are a plurality of CLSF processing units in the network, or data is stored in the CLSF processing unit of the next stage which is predetermined by the routing rule. The gram is converted into an ATM cell again and transmitted.

In the CLSF processing section, it is not always necessary to reproduce the datagram and then analyze the destination address and convert the datagram into ATM cells for transmission, and the destination address is included in the first one cell in which the datagram is converted into ATM cells. If it is, the destination address in the first cell is analyzed, and the cell is directly transferred to the destination terminal,
A method may be used in which the datagram is converted into ATM cells and the second and subsequent cells are sequentially transmitted to the destination terminal.

However, in the above-mentioned method using CLSF, all the datagrams transmitted from within the network always pass through the CLSF processing section, and as the amount of datagrams to be transmitted increases, the terminals within the network also increase. As the number increases, the CLSF processing unit is required to have higher throughput, and the CLSF processing unit is required to have very high throughput and flexible expandability.

Another method of sending a datagram to a destination terminal is to connect an ATM connection, for example, a VC to the destination terminal, and convert the ATM cellized datagram to this V
It is a method of placing it on C and delivering it. However, in this method, it becomes very problematic to which destination terminal the VC is set. That is, since there are virtually an infinite number of partner terminals that can send datagrams, and the occurrence of datagrams is bursty, unlike voice information,
Establishing unnecessary connections wastes network resources.

Further, when realizing connectionless communication in the conventional ATM network, the ATM connection is always terminated in the CLSF processing unit, and a protocol process higher than the AAL layer, for example, a protocol process for connectionless service called CLNAP is performed. Done. That is, even when datagram communication is performed between terminals that are very close to each other, the ATM connection is once terminated in the CLSF processing unit. Further, when datagram communication is performed between distant terminals, the datagram passes through a plurality of CLSF processing units, and each CLSF processing unit performs protocol processing of the AAL layer or higher.

In general, CLNA above the AAL layer
Protocol processing such as P is performed by software processing (generally, hardware processing below the AAL layer is performed), and the processing speed is slow. Further, the CLSF processing unit does not only perform communication between terminals belonging to the network supported by itself, but also when communicating with terminals in the network supported by other CLSF processing units, the address information ( For example, it is necessary to analyze (network layer address information), and the load of datagram transfer processing is concentrated on the CLSF processing unit. For these reasons, the conventional ATM communication system has a problem that it is difficult to realize high-speed communication in connectionless communication (datagram delivery) between terminals.

An object of the present invention is to provide an ATM without sacrificing high speed, large capacity and connection oriented property.
An object is to provide an ATM communication system capable of realizing communication between networks.

Another object of the present invention is to provide an ATM communication system capable of efficiently carrying out datagram delivery using an ATM network.

Still another object of the present invention is to provide an ATM communication system capable of performing connectionless communication between terminals connected to an ATM network, that is, datagram delivery at high speed.

[0033]

In order to solve the above problems, the ATM communication system according to the present invention is configured as follows.

(1) A plurality of ATM networks operated in the asynchronous transfer mode, a plurality of terminals respectively accommodated in the plurality of ATM networks, and a plurality of ATM networks provided between the plurality of ATM networks. And an inter-network connecting device for performing internetworking, wherein the inter-network connecting device is at least a part of packets transmitted from one ATM network connected to the inter-network connecting device to another ATM network. Packet is not processed above the ATM adaptation layer, and at least the ATM layer processing is performed.
An ATM communication system characterized by performing at least one of cell header reference and ATM cell switching.

This network connection device preferably has an ATM cell header conversion means.

The network connecting device is preferably C
It has an LSF (connectionless service function) processing means. The CLSF processing unit performs network layer processing (network layer address analysis, routing processing, etc.) on at least a datagram that crosses the network connecting devices.

Further, an address resolution protocol in datagram delivery developed in the ATM network (when the network layer address of the destination of the datagram is known and the physical address to which the datagram is to be transmitted is unknown, In the protocol for acquiring a physical address from a network layer address), the AT
Regarding the resolution of addresses located outside the M network, VPI connected to the CLSF processing unit in the inter-network connection device is used.
/ VCI may be notified.

(2) A plurality of ATM networks operated in the asynchronous transfer mode, a plurality of terminals respectively accommodated in the plurality of ATM networks, and a plurality of terminals provided between the plurality of ATM networks are provided between the ATM networks. Internetworking device for internetworking, and the internetworking device has connectionless service processing means.

The connectionless service processing means performs network layer processing on at least a datagram delivered over an inter-network connecting device having the connectionless service processing means, and three or more ATs are provided.
The delivery of the datagram across the M network may be performed by relaying between the connectionless service processing means.

When there are a plurality of network connecting devices, the CLSF processing means in the network connecting devices may be connected by a permanent connection.

Further, the connection connecting the CLSF processing units in the inter-network connecting device may be a connection which is not a management target of the band management entity.

Further, this inter-network connecting device may internally have a call / connection processing means (a part having a function of setting, disconnecting, changing and managing a call and / or a connection).

Further, the call / connection processing means in the inter-network connecting device may perform at least a process for a call / connection across the inter-network connecting device.

Further, regarding the address resolution protocol for detecting the call processing involved in the call / connection setting / change / disconnection processing deployed in the ATM network, the call / connection to be processed is the ATM network. For address resolution with an address located outside, VPI / VCI addressed to the call processing unit in the inter-network connection device may be used.

Further, the call / connection processing means in the ATM network relays the call / connection processing to the call processing in the inter-network connecting apparatus when the target call / connection is not closed in the ATM network. You may ing.

(3) A plurality of ATM networks operated in the asynchronous transfer mode, a plurality of terminals respectively accommodated in the plurality of ATM networks, and a plurality of ATM networks provided between the plurality of ATM networks. And an inter-network connecting device for performing internetworking, wherein the inter-network connecting device has a call processing means, and the call processing means processes a call / connection across at least the inter-network connecting device having the call processing means. Give.

The call processing means may perform call / connection processing across three or more ATM networks by relaying between the call processing means.

The call processing means in the inter-network connection device may be connected by a permanent connection.

(4) A plurality of ATM-LANs operated in the asynchronous transfer mode, a plurality of terminals respectively accommodated in the plurality of ATM-LANs, and the plurality of ATM-Ls.
At least one datagram server provided in the entire AN, connection setting means for setting an end-to-end ATM connection between the plurality of terminals accommodated in the same ATM-LAN, and the same ATM- L
Datagram delivery between the plurality of terminals accommodated in the AN is performed through the ATM connection set by the connection setting means, and the different ATM
An ATM communication system comprising: a datagram delivery means for delivering a datagram between the plurality of terminals in the LAN through the datagram server.

Here, the datagram server performs the following processing. An ATM cellized datagram (connectionless packet) is terminated once. However, it is not always necessary to reassemble the datagram. That is, it is not always necessary to terminate the network layer, and CC
The termination may be performed at the CL layer, which is being discussed by ITT. Then, after referring to the network layer address once, an appropriate ATM connection (VP / V connected to the node having the network layer address)
C, or V connected to the CLSF processing means which is considered to have a function of delivering the network layer address.
P / VC).

The terminal may set an end-to-end ATM connection with another terminal or address resolution at the time of booting or booting of the own terminal.

Further, the terminal may set an end-to-end ATM connection with another terminal or perform address resolution when the terminal logs in.

In the above datagram delivery system, when the ATM connection between the terminals in the same ATM-LAN cannot be established or the address resolution cannot be performed, the terminal sends the data. The gram may be transferred to a datagram server or may be broadcast in the ATM-LAN.

(5) A plurality of ATM networks operated in the asynchronous transfer mode, a plurality of terminals respectively accommodated in the plurality of ATM networks, and a plurality of data provided in at least one of the plurality of ATM networks. A gram server and an inter-network connection device that is provided between the plurality of ATM networks and performs internetworking between the ATM networks.
The network connecting device is an ATM connected to the network connecting device.
A for requesting address resolution from the network
In response to the RP request, if the target node of the address resolution does not exist in the ATM network connected to the inter-network connecting apparatus, the A for the ARP request is returned with the reply of the ATM address of the ATM connection connecting to the inter-network connecting apparatus.
Response means for making an RP response and ARP from this response means
The first indicated by the ATM address returned by the response
Between the transmission terminal of the datagram and the datagram server, and a connection connecting means for connecting the ATM connection of the datagram and the second ATM connection established between the network connection device and the datagram server. An ATM communication system characterized in that the above are directly connected by an ATM connection.

(6) A plurality of ATM networks operated in the asynchronous transfer mode, a plurality of terminals respectively accommodated in the plurality of ATM networks, and a plurality of data provided in at least one of the plurality of ATM networks. A gram server and an inter-network connection device that is provided between the plurality of ATM networks and performs internetworking between the ATM networks.
The inter-network connecting device performs address resolution when receiving an ARP request for requesting address resolution from the first ATM network connected to the inter-network connecting device and the routing protocol terminating means. AR
A notification means for notifying the P server of information relating to routing, and a first ATM address indicated by the address resolution response from the address resolution server for the information passed by the notifying means. A second AT set between one ATM connection and the network connection device / datagram server
An ATM communication system comprising a connection connecting means for connecting an M connection, and the datagram transmission terminal and the datagram server are directly connected by an ATM connection.

(7) Here, the connection connection means in (5) or (6) is, for example, a connection between the first ATM connection and the second ATM connection, which is composed of an ATM cell header conversion means and an ATM cell switching means. It is configured to be performed by at least one.

In this case, it is possible to increase or decrease or change the datagram server by setting at least one of the ATM cell header converting means and the ATM cell switching means.

(8) AT operated in asynchronous transfer mode
An M network and a plurality of terminals accommodated in the ATM network are provided, and the terminal serves as an ATM communication board to request an address resolution addressed to the terminal from an ATM cell from the ATM network. ARP request cell extracting means for extracting the ARP request cell, and an AR for making a response to the address resolution request based on the ARP request cell extracted by the ARP request cell.
An ARP response cell generating means for generating a P response cell, and a multiplexing means for multiplexing the ARP response cell generated by the ARP response cell generating means with an ATM cell stream sent from the terminal device. ATM communication system.

The operation of the ATM communication system according to the present invention will be described below.

(1) In the conventional ATM communication system, the packet input by the inter-network connecting device is processed in the upper layer (data link layer, network layer or higher layers). On the other hand, in the present invention, in the inter-network connecting device, a part of the packets sent from one ATM network connected to the inter-network connecting device to an ATM network different from this is not processed by AAL or more,
Among the ATM layer processes, at least the reference of the ATM cell header and / or the switching of the ATM cell is used for transmission. As a result, the AT that spans the network connection devices
M connections (VP, VC) can be created without terminating the connection at the inter-network connection device. Since this ATM connection passes through the inter-network connection device only by the ATM layer processing without being terminated in the upper layer, it is possible to speed up the data across each network and transfer a large capacity.

In the ATM network, the range covered by the physical address system can be judged as one closed network (ATM-LAN). That is, it can be determined that the range of the entity that determines the value of VPI / VCI, which is the physical address system in the ATM network, is one ATM-LAN.
The entity that determines the value of this VPI / VCI is ATM-LA.
There are one or more in N, and these operate in cooperation. In this way, ATMs with independent VPI / VCI systems
-In the inter-network connection device that connects LANs, these address systems are converted, that is, VPI / VC on one side.
There is a need for a mechanism for address translation from the I address system to the VPI / VCI address system on the other side. By having the ATM cell header converting means in the network connecting device, it is possible to refer to the ATM cell header value such as the VPI / VCI value, and it is possible to transfer the address system by the converting means. .

(2) In the present invention, CLS is provided in the inter-network connection device.
By providing the F processing means, it is possible to process (terminate) the datagram delivered across the inter-network connecting devices. When the datagram is delivered using the CLSF processing means, the ATM connection is once terminated by the CLSF processing means, and the ATMcellized datagram is once transferred to the upper layer (network layer or CL layer) processing. That is, the network layer address or CL layer address is referred to. In this case, datagram reassembly is not necessary. After this, the AT leading to the referenced address
M connections are selected and the datagram is sent over the ATM connection.

By arranging the CLSF processing means in the inter-network connecting device in this manner, the ATM connection is terminated here for the datagram delivered across the networks. The CLSF processing means can be directly accessed from the ATM network connected to the inter-connection device. In addition, this access can be performed without using an ATM connection across multiple networks. (2) AT connected to the inter-network connection device
With regard to the datagram distribution across the M networks, by performing the processing here, the conversion of the address system (VPI / VCI value) in each ATM network can be intensively performed here, and further (3) Routing information (network layer address, CL) connected to the network connection device
It is possible to enjoy an advantage such that there is no need to exchange (relation information of layer address and VPI / VCI value) between networks.

The AT connected to the inter-network connection device
In the M network (ATM-LAN), when the terminal that wants to send the datagram detects where to send the datagram, the sending address of the datagram is sent to the outside of the ATM-LAN at the time of address resolution. If the address is located, the CLSF in the inter-network connection device
The VSF / VCI connected to the processing means is notified by, for example, the CLSF processing means itself or an ARP server which will be described later, so that the datagram can be uniformly delivered to the outside of the network.

The above configuration can be applied not only to the inter-network connecting device between the ATM networks but also to the inter-network connecting device between the ATM network and the networks operated by another system (for example, Ethernet system).

When the datagram delivery extends over three or more networks, the CLS arranged in the inter-network connecting device is used.
By performing this by relaying between the F means, the datagram delivered to the outside of the own ATM-LAN is sent to the CLSF processing means arranged in the inter-network connecting device, and the CLSF processing. It is possible to maintain a method in which the datagram destination to be managed by the means is only the terminal / node in the network connected to the inter-network connecting device, excluding other CLSF processing means, and efficient CLSF is possible.
Operation can be planned.

Here, the connection between the CLSF processing means is made by a permanent connection, specifically PVP (permanent VP) or PVC (permanent VC), so that a connection is generated each time a datagram is transferred between the CLSF processing means. Since the setting overhead can be reduced, and the delivery of the datagram across three or more networks can be performed via the permanent connection, the traffic used for delivering the datagram. Can be easily monitored.

(3) Further, the datagram delivery is usually performed by the unreliable connection. That is, it can be considered that the transmission is performed on the assumption that the transmitted datagram may be lost on the way or that the delay time until the transmitted datagram reaches the transmission destination cannot be predicted. Therefore, the connection connecting the CLSF processing means is also a connection that is not managed by the bandwidth management entity, that is, a connection with a low cell delivery priority, which is excluded from the connection connection control for bandwidth management when setting the connection. Can be As a result, a strategy of preferentially passing through the cells of the connection (connection with high priority) subject to connection connection control is taken, but the datagram delivery is appropriate in its nature.

By providing a call / connection processing means in the inter-network connecting device, the processing (setting, disconnection, change, management, etc.) of the ATM connection across the inter-network connecting devices is processed (terminated) here. be able to. As a result, (1) the processing of the ATM connection across the inter-network connection device requires information in both networks to be connected. By arranging the call / connection processing means in the inter-network connecting device located between the respective networks and capable of knowing the information in the respective networks, it is possible to efficiently process the ATM connection across the inter-network connecting devices. You can (2) From each network connected to the inter-network connection device,
The call / connection processing means can be accessed. Further, this access can be performed without using an ATM connection that spans a plurality of networks. (3) The call / connection processing means in the inter-network connecting device can be specialized in processing an ATM connection across the inter-network connecting device. (4) For ATM connections that cross networks, it is necessary to convert each ATM address system (VPI / VCI system) in the network connection device. By providing a call / connection processing means in the network connecting device, the VPI / V
It is possible to enjoy the advantages that elements essential for address system conversion, such as CI system conversion table setting means, can be included in the call / connection processing means, or can be closely coupled to the processing means.

Further, A connected to the above-mentioned network connecting device
In the case of address resolution in a TM network (ATM-LAN), a terminal that desires a call / connection processing request (setting, disconnection, change request, etc.) detects where to send the processing request, When the connection destination address of the call / connection is an address located outside the ATM-LAN, it is notified outside the network by notifying the VPI / VCI connected to the call / connection processing means in the inter-network connecting device. Call / connection processing can be performed in a unified manner.

If the ATM-LAN is provided with a call / connection processing means, and if the processing for the requested call / connection is closed within the ATM-LAN, the call / connection processing means within the ATM-LAN If processing is performed in the call / connection processing means and the processing is a processing request with an entity outside the ATM-LAN, a call in the inter-network connection device that manages the processing of the call / connection with the outside of the ATM-LAN /
By relaying the processing to the connection processing means, it is possible to perform the processing related to the call / connection with the outside of the network in a unified manner.

The above configuration can be applied not only to the inter-network connecting device between the ATM networks but also to the inter-network connecting device between the ATM network and the networks operated by another system (for example, Ethernet system).

When the above-mentioned call / connection processing extends over three or more networks, relaying between the call / connection processing means arranged in the inter-network connecting device does this, so that the own ATM- Regarding the ATM connection to the outside of the LAN, the method of transmitting to the call / connection processing means arranged in the inter-network connecting device and the entity (terminal, node, etc.) managed by the call / connection processing means are other It is possible to maintain a method in which only terminals / nodes in the network connected to the inter-network connecting device are excluded, excluding the call / connection processing means, and efficient operation of call / connection processing can be achieved.

The connection between the call / connection processing means is a permanent connection (PVP or PV
By performing the processing in C), it is possible to reduce the connection setting overhead which occurs each time the processing information is transferred between the call / connection processing means, and the processing of the call / connection across three or more networks is performed by the permanent. It is possible to always perform relaying between call / connection processing means in the inter-network connecting device via the connection. Further, it is possible to facilitate monitoring of traffic used for call / connection processing.

(4) As described above, in the LAN environment, unlike the wide area network environment, it is considered that the application program requires a sufficiently small latency and a short call setup time for the LAN. Since the datagram does not require call setup, the latter requirement described above can be satisfied. However, when the datagram server is used in the ATM environment, the retention time of the datagram in the datagram server generally becomes a problem. , I can't secure a small latency. An environment that especially requires a small latency is
Since it is considered to be an application in the LAN (propagation delay is inevitable because there is a physical distance in the WAN environment), terminals in the ATM-LAN have the same AT.
By providing an ATM connection end-to-end with other terminals in the M-LAN and performing datagram delivery, both of the above requirements can be satisfied. In addition, since the communication volume of datagrams within a LAN is generally considered to greatly exceed the communication volume of datagrams across LANs, the exchange of datagrams completed within the LAN is handled via a datagram server. Without doing so, it is possible to prevent the datagram server from requesting excessive throughput. In this case, for a datagram that spans a plurality of networks, the datagram may be delivered through a datagram server having a datagram delivery means.

Further, when a datagram to be transmitted is generated, the terminal device for transmitting the datagram causes the datagram to stand by on the ATM communication board or an arbitrary memory to set the ATM connection or address resolution. The physical address (VPI in case of ATM network)
It is not always necessary to take out a datagram from the ATM communication substrate or an arbitrary memory after the / CCI value or other ATM cell header value) has been found out, convert this into an ATM cell, assign the physical address, and send it out. . This is because the time during which the ARP is being performed is a waste of time from the standpoint of sending a datagram, because the datagram is in a waiting state. It is considered that efficient datagram distribution can be achieved by setting the ATM connection or address resolution in advance for the destination terminal that may send the datagram. This end-to-end ATM connection setting or address resolution may be performed when the terminal device is started up (booted) or when logged in.

If an ATM connection between terminals within the same ATM-LAN cannot be established,
Alternatively, when the address resolution cannot be performed, the terminal can enable communication by the datagram by transferring the datagram to be transmitted to the datagram server. This is because it is generally considered that the datagram server has the ability to deliver the datagram to the destination terminal of the datagram (because the datagram server is the ATM-LAN.
Since it recognizes the existence of all network layer addresses of the node / IWU / terminal connected to the same ATM-, the same ATM-
The reason is that the datagram can be delivered to the LAN by the datagram server even if there is no end-to-end ATM connection or the datagram sending terminal cannot recognize the ATM connection.

If an ATM connection cannot be established between terminals within the same ATM-LAN,
Alternatively, when the address resolution cannot be performed, the terminal sends the datagram to be sent to the ATM-L.
If it is broadcast in AN, the AT
Information can be transmitted because all terminals in the M-LAN are receiving and analyzing.

(5) Next, an inter-network connection device according to the present invention will be described. Generally, in the inter-network connection device,
It is possible to directly collect information about the network connected to the device (information about what kind of network layer address or other address the node has, how it should be routed; routing information). Because of its position, it is the main operating point of the routing protocol (both in the sense of exchanging routing information in the backbone network and in the sense of routing information concentration point in the branch network).
Has become. In the existing inter-network connecting device (so-called router in LAN), the meaning of "routing protocol end point" and the network layer address of the datagram input to the inter-network connecting device are analyzed. However, it has two functions in the sense that "routing of the input datagram" is performed based on the routing information obtained through the above-mentioned routing protocol. On the other hand, in the ATM network, the latter function, that is, the function of "analyzing the network layer address of the input datagram and routing the datagram based on the routing information obtained through the above-mentioned routing protocol" Is a function of the datagram server,
Generally requires high cost and complicated equipment. In addition, it is considered to waste communication resources to provide a large number of datagram servers as described above even though the total amount of datagrams actually communicated is not so large.

(6) Therefore, as in the present invention, the routing protocol terminating means and the datagram service processing means are separated, and the AT resulting from the address resolution is further separated.
If an M address is required (when the address resolution destination node is not connected by an end-to-end ATM connection, that is, not in the same ATM-LAN), an ATM address leading to the datagram server By doing so, it is possible to provide the datagram service at an appropriate cost and scale without using the required number of datagram servers.

(7) In the inter-network connection device, the ATM address returned in the ARP response is used.
ATM connection connecting to the network connecting device and ATM connecting the network connecting device to the datagram server
The connection with the connection is made by setting the ATM cell header converting means or / and the ATM cell switching means in the inter-network connecting device so that the datagram transmitting terminal and the datagram server are directly connected by ATM, that is, ATM. It can be combined only by layer processing.

In addition, in an ATM network that transfers datagrams between an arbitrary terminal and a datagram server in the above-described manner, when the number of datagram servers is increased or decreased or changed, the ATM in the inter-network connection device is used. By doing this by changing the setting to the cell header converting means and / or the ATM cell switching means, the setting change when the datagram server is added or removed, or when the datagram server is changed is only a simple table change in the inter-network connection device. In addition, it can be easily performed in a very short time.

(8) By using a terminal (ATM communication board) as in the present invention, generally, a broadcast channel (from an arbitrary transmission side terminal to all nodes / IWUs / terminals belonging to the ATM-LAN, A rapid response to an ARP request cell (address resolution request cell), which is considered to be performed via an ATM connection capable of broadcasting the transmitted cell, and a high-order processor (inside the terminal device) (CPU) Etc.) can be performed without consuming processing time.

As described above, the entire network of the ATM communication system is composed of a plurality of ATM networks.
That is, by forming a subnet, the distinction between the address analysis protocol and the routing protocol is clarified, and the expansion of the network can be flexibly dealt with.

[0085]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 shows an ATM network according to the first embodiment. As shown in the figure, the ATM network of this embodiment includes a first ATM-LAN 11, a second ATM-LAN 12, an inter-network connection device (hereinafter, IWU).
It is also called) 13.

First ATM-LAN 11 and second ATM
-The LAN 12 is a local area network operated by the ATM system. Each ATM-LA
Within N, the address system is independent. That is, the VPI / VCI value used inside each ATM-LAN has the authority to be determined by the VPI / VCI value determination function existing inside the ATM-LAN, and this authority is to each ATM-LA.
Independence at N. The terminal device and the node in the ATM-LAN store the information in the ATM cell when the information to be transmitted exists (whether the transmission destination is in the ATM-LAN or not). A proper ATM
A cell header is added and the cell header is transmitted into the ATM-LAN.

FIG. 2 shows a diagram of the internal structure of the inter-network connecting device 13. The inter-network connection device 13 includes an add / drop processing unit 21, a multiplexer / demultiplexer (hereinafter,
MUX / DEMUX) 22, CLSF processing unit 2
3, a call processor 24, an IWU manager 25, and an ATM cell header converter 26. The inter-network connection device 13 is located between two ATM-LANs and has a function of controlling internetworking (inter-LAN connection) of the two ATM-LANs.

The add / drop processing section 21 refers to the header section of the input ATM cell, and if the cell has an appropriate header value (that is, the cell is in the inter-network connection device 13). If the cell is to be terminated, the cell is dropped on the DEMUX 22 side and the cell from the MUX 22 side is inserted (added) on the cell transmission line. Here, the add / drop processing unit 21 has a function of dropping cells from either the left or right side on the cell transmission line, and a function of inserting cells into the cell transmission line in either the left or right direction.

In the add / drop processing unit 21, information regarding which of the left and right cell transmission paths is to be used to insert a cell is specified by each of the CLSF processing unit 23, the call processing unit 24, and the IWU management unit 25, which will be described later. Shall be done. That is, for example, if the cell is inserted in the cell transmission line in the left direction, the inserted cell is passed to the add / drop processing unit 21 together with a value such as 0, and if it is in the right direction, the add / drop processing unit 21 refers to this value and inserts it. Decide the direction. Further, the location where the cell is inserted may be such that when an empty cell is passing through a cell slot on the cell transmission line, the empty cell is replaced and inserted.

When dropping cells from the add / drop processing section 21 to the MUX / DEMUX 22 side,
A drop table as shown in FIG. 3 is referred to. This drop table is provided in each of the left and right cell transmission lines, and the cell drop destination (CLSF processing unit 23, call processing unit 24, or IWU management unit 25) is determined according to the value of this table. As shown in FIG. 3, the drop table uses the cell header value as an entry, and the value indicating the drop destination is referred to. As the value that indicates this drop destination,
For example, 1 is assigned to the CLSF processing unit 23, 2 is assigned to the call processing unit 24, 3 is assigned to the IWU management unit 25, and the like. The cell dropped by the add / drop processing unit 21 is a value indicating this drop destination,
It is sent to the MUX / DEMUX 22 side together with a value indicating whether the cell is a drop cell from the left or right direction (eg, 0 from the left direction, 1 from the right direction).
The information on this drop table is the IW described later.
The U management unit 25 performs initialization, addition, change, and the like.

The MUX / DEMUX 22 refers to the cell (drop cell) sent from the add / drop processing section in parallel with one of the modules connected to the lower part (CLSF processing in this embodiment). Part 2
3, the function to send to the call processing unit 24, the IWU management unit 25) (DEMUX function), and the cell (add cell, inserted cell) to be inserted into the cell transmission line sent from the module group connected to the lower part are multiplexed. The add / drop processing unit 21 has a function (MUX function) of passing along with information on which direction to insert.

The CLSF processing section 23 is for performing processing of a connectionless service function. As will be described in detail later, the CLSF processing unit 23 once terminates a datagram (connectionless packet) delivered across the inter-network connecting device 13 (note that it is not always necessary to reassemble the datagram. That is, it is not always necessary to terminate the network layer, but it is also possible to terminate at the CL layer, which is being discussed in CCITT), and after referring to the network layer address once, an appropriate ATM
It has a function of sending to a connection (VP / VC connected to a terminal / node having the network layer address, or VP / VC connected to a CLSF processing unit considered to have a function of delivering the network layer address). It should be noted that the CLSF processing unit 23 terminates the ATM connection for datagram delivery once.

The call processing unit 24 is basically the inter-network connection device 1
Setting, disconnecting, and changing ATM connections across 3
It has the function of managing. Further, it may have a function of managing the ATM connection or the band on the ATM transmission path in the inter-network connecting device. Details will be described later.

The IWU management unit 25 has a function of managing and controlling the inter-network connecting device 13.

The header converter 26 (from both left and right directions)
It has a function of referring to the header value of the input cell and rewriting the header value to another header value when the header value is an appropriate value. Since the header conversion unit 26 basically has a function of referring to the cell header value (input cell header value) and rewriting it to a certain cell header value (output cell header value), the input cell header value and the output cell header value It internally has a correspondence table with. The IWU management unit 2 performs initialization, addition, change, etc. of this correspondence table.
It is done by 5. This correspondence table corresponds to the drop table of FIG. 3 in that the entry value is the input cell header value, so that the table can be easily integrated with the drop table.

Each module in the inter-network connecting device 13 is assumed to be bus-connected (not shown), and the IWU management unit 25 controls the setting values of each module through this bus. Shall be given.

Instead of exchanging information between each module through the bus as described above, this may be done by placing the information on the ATM cell and exchanging the cell between the modules.

In the present embodiment, various processes (CLSF process, call process, etc.) on the cell transmission lines in both the left and right directions are performed by the same module on the left and right, but this may be performed on the left and right directions. It is possible.

Further, in the present embodiment, various processes in the present IWU are separately performed (that is, the CLSF processing section is performed by the CLSF processing dedicated module, and the call processing is performed by the call processing dedicated module. Do all) or some of these processes on the same CPU / MPU
It is also possible to do in.

Although the case where there is only one header conversion unit 26 in the inter-network connecting device of FIG. 2 of the present embodiment is described, before the add / drop for the ATM cell flow in both the left and right directions. , And / or a header converter is provided afterwards,
A method for converting the header of each one-way ATM cell (FIG. 38), or an add / drop processing section before and after the header converting section as shown in FIG. A method of performing the add / drop of the ATM cell is also considered. By doing so, the functions of the inter-network connecting device 13 can be seen symmetrically when viewed from both left and right directions.

Next, in FIG. 4, the first ATM-LAN 11,
1 shows an embodiment of a node / terminal configuration inside the second ATM-LAN 12. Thus, the first ATM-LAN
11 is three switch nodes 41, 42, 43,
It is composed of terminals 4A, 4B, 4C, 4D connected to these. The second ATM-LAN 12 has two switch nodes 44 and 45 and terminals 4E connected to them.
It consists of 4F and 4G.

An ATM switch is mounted in each switch node to connect switch nodes to each other, to connect to an inter-network connecting device, and to connect to a terminal device. In that case, a star type (or tree type, etc.) ) Will be taken. The interface speed between these switch nodes and the terminal device / switch node / inter-network connection device is 10M,
Various values such as 20M, 155M, and 622M can be selected.

Next, FIG. 5 shows an embodiment of the ATM connection connection state between the terminals in both ATM-LANs and the CLSF processing unit in the inter-network connection device 13. Here, for simplification, wiring between terminals / switch nodes and between switch nodes / inter-network connection devices is omitted. Further, other components such as a call processing unit and a header conversion unit in the inter-network connecting device are omitted in the drawing.

In this way, each terminal device and the inter-network connection device 1
The CLSF processing units 23 in 3 are connected by ATM connections. This ATM connection is V
It may be P or VC. This ATM connection is a connection that is not subject to bandwidth management.
That is, when physically establishing an ATM connection between the terminal device and the CLSF processing unit 23 in the inter-network connection device 13, no bandwidth reservation is made (that is, when performing call admission control, bandwidth management is performed). (Without going through the evaluation function). AT that does not perform such bandwidth management
The M connection is considered to have a lower priority than the ATM connection that performs bandwidth management. That is, comparing parameters such as cell delivery delay or cell loss rate with an ATM connection that performs bandwidth management,
An ATM connection that does not perform bandwidth management will show a bad value. The ATM connection that connects this terminal device and the CLSF processing unit is used for delivery of datagrams, but originally, the delivery of datagrams requires a large delay time and an unreliable physical connection. Because it was thought of as
It is reasonable to use a connection.

As described above, the ATM is used in this embodiment.
An ATM connection within the LAN (in some cases A
As for the ATM connection that extends between the TM and the LAN), there are an ATM connection that performs bandwidth management and an ATM connection that does not perform bandwidth management. ATM connection for bandwidth management has a certain communication quality (QOS)
Is a connection that can maintain communication (a cell discard rate above a certain level, a delay time below a certain level can be expected), and an ATM connection without bandwidth management is a connection (cell There is no limit on the discard rate and delay time).

An ATM connection that performs bandwidth management is considered to have a high priority, and an ATM connection that does not perform bandwidth management is considered to have a low priority. For example, priority is given only when there is no cell belonging to a high priority connection. This can be achieved by performing priority control such as permitting passage of cells belonging to connections with low frequency.

Regarding an ATM connection for performing bandwidth management, the connection is permitted only when the cell transmission path through which the connection passes and the communication resources in the switching node are secured. Since the ATM connection that does not perform the call is not subject to bandwidth management, even during call / connection admission control,
As long as it is less than or equal to the maximum number of acceptances (of each connection management entity), it is accepted unconditionally.

The ATM connection connecting this terminal device and the CLSF processing unit 23 in the inter-network connection device 13 is
It should be noted that it does not extend across the network connection device, that is, it does not extend over the ATM-LAN. ATM-L
When setting up an ATM connection across ANs, generally, as will be described later, negotiation between both ATM-LANs, address conversion, protocol conversion, etc. are generally required, and a CLSF processing unit is provided in the inter-network connecting device. By providing such an ATM connection, it is not necessary to provide such an ATM connection across the ATM-LAN for datagram delivery.

Now, the terminal device delivers the datagram via the inter-network connecting device 13, that is, outside the own ATM-LAN, via the CLSF processing unit 23 in the inter-network connecting device 13. . That is, although the ATM cellized datagram is sent to the CLSF processing unit 23, there are several approaches until the terminal device knows that the datagram should be sent to the CLSF processing unit 23. The method of can be considered.

From the destination address of the datagram to be sent (the network layer address or the mail address including the domain name may be used), the terminal device
Which ATM address (ie, which VP
I / VCI value) must be attached before resolution. Thus, V added to the datagram / ATM cell sent from the destination address
The work of resolving the PI / VCI value is learned from the ARP (Address Resolution Pr
otocol: Address resolution protocol).

There are several methods for realizing this ARP as follows.

(Method 1): VP addressed to CLSF processing section in advance
When I / VCI is assigned.

In this case, the ATM of the CLSF processing unit is previously set.
This is a system in which an address (VPI / VCI) is uniquely assigned to a LAN, and a datagram may be unconditionally attached with the VPI / VCI and transmitted.

In such a system, the terminal uses its own ATM-
Since it is impossible to distinguish the delivery of the datagram into the LAN and the delivery of the datagram to another LAN via the inter-network connecting device, the CLSF processing unit 23 in the inter-network connecting device 13
However, it is also necessary to have a function for delivering a closed datagram in the ATM-LAN. In addition, as shown in FIG.
A CLSF processing unit is separately prepared in the TM-LAN, and for datagram delivery across the inter-network connecting device, the datagram is relayed to the CLSF processing unit in the inter-network connecting device. The delivery method is included in this method (previously ATM-
VPI / VCI addressed to the CLSF processing unit in the LAN is defined). (Method 2): Method using ARP server There is an ARP server (not shown) in the ATM-LAN, and the terminal device sends to the ARP server which VPI / VCI datagram of the destination address. It is a method of asking if you should send it out with.

The ARP server has a table inside, and this table has a destination address and VPI /
It corresponds to the VCI value. A who received the inquiry
The RP server uses the VPI / VC corresponding to the destination address.
The I value is analyzed by referring to the internal table, and the analysis result (VPI / VCI value) is returned to the terminal device of the inquiry source. At that time, if an ATM connection is not established between both terminal devices / nodes, it may be notified, or the ARP server sets up an ATM connection between both terminals / nodes, and then the The VPI / VCI value of the ATM connection may be returned. In this way A
RP is performed.

[0117] Here, the terminal device is the AT of the ARP server.
M address (VPI from the terminal device to the ARP server /
It may be possible to know the VCI value) or not.

If the user knows, there is no problem if an inquiry is made using the VPI / VCI value.

If not known, the AT of the ARP server itself
M address resolution (ARP) or broadcast channel is used to send the inquiry.
A method is conceivable in which the broadcast is carried out in the TM-LAN, and the broadcasted inquiry is recognized by the ARP server as an inquiry to itself and the subsequent processing is performed. When this broadcast channel is used, its own address (network layer address, mail address if necessary, ATM address VPI / VCI value, server name (AR
P server), the physical address given to the communication board, etc., the destination address (the network layer address of the entity that wants to receive the broadcast cell,
If necessary, it is necessary to include at least mail address, ATM address, server name, function name, etc., and broadcast cell type (what kind of meaning the broadcast cell has) (FIG. 7). In addition, "this protocol address" is added to this own address (source address) and destination address (receiver address).
An area indicating (for example, IP address, E.164 address, or the like) may be included. In addition, when the same sender simultaneously makes multiple requests to the same destination,
A random number, a discrimination number, or the like may be added in the cell to indicate which request the response is for.

When this broadcast cell is used for ARP, for example, in the other information field of FIG. 7, the address of the terminal device / node which is the target of the address resolution (network layer address, mail address if necessary) Etc.) at least. In this case, the receiving side address in the broadcast cell format may be indefinite (for example, all 1). The reason for making the receiving side address indefinite is that the receiving side address in the broadcast cell is the address of the receiving target terminal of the broadcast cell. This is because when a broadcast cell is used for ARP, it is not considered that the terminal device targeted for address resolution necessarily responds to the ARP, that is, it is not considered that the cell that performs the ARP is received and processed. .

When performing this broadcast, for example, VPI = all 1 is used. VCI = all 1's may be used, or broadcast cell type information may be included in the VCI value.

As an example of performing ARP using broadcast, for example, an appropriate ARP server that receives a broadcast cell (ARP cell) refers to the broadcast cell type, and this is a datagram transmission request ARP. Further, it recognizes that the ARP request is to be processed through the CLSF processing unit in the inter-network connecting device, recognizes it by referring to the address for address resolution, and recognizes the CLSF in the inter-network connecting device. ATM address for processing unit (VP
In some cases, the I / VCI value) is returned. FIG. 8 shows an example of the format of the broadcast cell when such ARP is performed using the broadcast cell.

A request for address resolution is sent to the ARP server (end-
Even if done through the end ATM connection)
It is needless to say that the inquiry needs to include the target address of the address resolution.

When the ARP server recognizes that the destination of the datagram is the destination of the inter-network connecting device (that is, outside the own ATM-LAN), the resolution results in the inter-network connecting device. The ATM address (VPI / VCI value) to the CLSF processing unit is returned.

In order to recognize this [destination of the datagram is the destination of the inter-network connection device], the destination address of the datagram is the own AT using, for example, a subnet mask.
A method of checking whether or not it has a sub-address of M-LAN can be considered.

Several methods can be considered when the ARP server returns the analysis result to the inquiry source.

First, there is a method of returning the inquiry result using a broadcast channel. In this case, the broadcast cell type in FIG. 8 indicates that the reply is ARP, and the ATM address (VPI / VCI), which is the result of the address resolution, replaces or continues to enter the address for address resolution. .

The details will be described later.
1267 proposed method (here, this is V
The P-routing method), that is, one VPI is assigned to each terminal / node and the routing in the ATM-LAN is performed using the VPI. ARP is performed as the "sending request ARP".

In other words, the ARP does not necessarily return the "datagram transmission request ARP" (VPI / VCI of the ATM connection directly connected to the other end-to-end. For example, the ATM connection to the CLSF processing unit. It is possible that the VPI / VCI value of the
P "(VPI / VCI of ATM connection directly connected with the other end-to-end is returned). .

(Method 3) Method via Call Processing Server A terminal device desiring ARP requests a call processing server (not shown) existing in the ATM-LAN to set up an ATM connection with a CLSF processing unit. It is a method to do.
The call processing server may establish an ATM connection with the CLSF processing unit in the inter-network connecting device when it recognizes that the delivery destination of the datagram is across the inter-network connecting device.

(Method 4) Direct ARP between Terminals / Nodes One VPI is assigned to each terminal / node in the ATM-LAN, and routing in the ATM-LAN is performed using VPI (VP routing). Method), A
The RP does not go through any server, and the CLSF processing unit 23 in the datagram transmission terminal and the network connection device 13
Can be done directly between. That is, the terminal device issues an ARP request using the broadcast channel.

The contents of the request cell are as shown in FIG. The source address is the address of the terminal device itself (may be VPI value or VPI / VCI value), the receiving side address is the address of the other party, or undefined, and the ARP destination address is the address of the other party. In this case, since there are two destination address areas, which are considered redundant, it is possible to simplify the format of the ARP cell (broadcast cell) as shown in FIG. 37 for direct ARP. It is possible.

The inter-network connecting device 13 that has received this (if necessary, the CLSF processing section 23 of the inter-network connecting device 13 may be used. In this case, the broadcast cell type is identified in the drop table and the ARP is used. If so, it may be set so as to be dropped in the CLSF processing unit 23), and when it recognizes that this is a datagram delivered across the inter-network connection device, the ATM address for itself is the address. Therefore, the resolution result is returned to the inquiry source terminal device with the VPI of the inter-network connection device 13 and the required VCI value. This is because the inquiry source terminal device adds the VPI / VCI value and sends the cell, so that the cell reaches the inter-network connection device according to the VPI value and is dropped to the CLSF processing unit according to the VCI value. become. When returning the resolution result, the broadcast channel may be used, or this may be performed via the VP addressed to the inquiry source terminal device.

The ATM-LAN does not necessarily need to apply the VPI routing, and the ARP is directly applied in the general case where the receiving side terminal recognizes the ATM address of the ATM connection with the transmitting side terminal. It is possible.

As described above, the ARP relating to the delivery of the datagram across the inter-network connecting device is performed, and the terminal device that sends the datagram thereafter converts the datagram into ATM cells and then transmits the datagram. When the destination is a destination that crosses the inter-network connection device, the previously resolved ATM address (VPI / VCI) is used,
This is sent to the CLSF processing unit in the network connection device. Addresses that have been once resolved will be used hereafter. The CLSF processing unit in the inter-network connection device sets this once in the network layer or CL.
A that is connected to the destination after terminating at the layer and analyzing the destination address (after making ATM cells again if necessary)
The TM connection will be selected appropriately and the datagram will be delivered through it.

By arranging the CLSF processing unit in the inter-network connecting device in this way, (1) the CLSF processing unit from the network connected to the inter-network connecting device
Direct access to the processing unit is possible. Also,
This access can be performed without using an ATM connection that spans a plurality of networks. (2) Datagram distribution across ATM networks connected to the inter-network connection device is processed here, so that the address system (VPI / VCI) in each network is processed.
(Value) conversion can be done intensively here. (3) Routing information about the ATM network connected to the inter-network connection device (for example, network layer address,
The relationship information between the CL layer address and the VPI / VCI value and the existence information) is terminated by the inter-network connection device / CLSF processing unit /
Since it can be centrally managed, there is no need to exchange it across the network. You can enjoy the advantages such as.

In the ARP method (method 1 to method 4) described in this embodiment, the CLSF processing unit does not necessarily have to be present in the IWU, and the CLSF processing unit may be present at any position in the network. Conceivable.

Also, as described in detail in (Method 2), the ARP is returned as "datagram transmission request ARP" (not necessarily the VPI / VCI of the ATM connection directly connected end-to-end with the destination). Not limited to, for example, V of ATM connection to CLSF processing unit
It can be mainly classified into "PI / VCI value may be resolved" and "connection connection request ARP" (VPI / VCI of ATM connection directly connected with the other end-to-end is returned). Be careful of the points.

Next, FIG. 9 shows an embodiment of the ATM connection connection state between the terminals in both ATM-LANs and the call processing unit 24 in the inter-network connecting device 13. Here, for simplification, wiring between terminals / switch nodes and between switch nodes / inter-network connecting devices is omitted. Further, other components such as a CLSF processing unit and a header conversion unit in the inter-network connecting device are omitted in the drawing. Both ATM-LAN
Call processing units 91 and 92 are added therein.

As described above, each terminal device and the call processing unit 24 in the inter-network connecting device 13 are connected by the ATM connection. This ATM connection may be VP or VC. With this terminal device,
It should be noted that the ATM connection connecting the call processing units 24 in the inter-network connecting device 13 does not extend over the inter-network connecting device, that is, does not extend over the ATM-LAN like the CLSF processing unit. This ATM connection is a connection for signaling.

Further, in this case, it should be noted that only the call processing unit in the inter-network connecting device has the configuration information of both ATM-LANs.

If the terminal device / node in the ATM-LAN desires to establish an ATM connection across the inter-network connection device 13, this call processing unit 24 is used. The correspondence differs slightly depending on whether the ATM connection across the inter-network connecting device 13 is a connection for bandwidth management or a simple connection connection requiring no bandwidth management. The following is a description in order.

First, a description will be given of a case where only connection connection (bandwidth management is unnecessary) is required.

(Method 1) In the case where the terminal makes a connection connection request to the call processing unit in the inter-network connecting device.

In this case, "connection setting request AR
P ”will be performed. As described above, in the "connection setting request ARP", an ATM directly connected to the other party
Since the VPI / VCI of the connection is resolved, it corresponds to the general signaling discussed in CCITT.

First, a terminal device / node (referred to as a transmission side terminal) that desires to establish an ATM connection across the inter-network connecting device is a call processing unit 24 in the inter-network connecting device 13.
A connection connection request is issued to.

At this time, if the transmitting terminal does not know to which call processing unit the connection connection request should be issued, or if the signaling channel of which ATM address (VPI / VCI) is used, the connection setting between the networks is established. It is possible that you do not know if you can make a request. In this case, "call processing request ARP" that asks which call processing unit should issue the connection connection request.
Will be used. That is, the details are similar to the case of the CLSF processing unit, but the call processing request AR is set with the destination address of the receiving terminal as the address for address resolution.
Put out P. When transmitting the "call processing request ARP" through the broadcast channel, the fact is entered in the area of the broadcast cell type of the broadcast cell format. On the other hand, when the destination address is on the other side of the inter-network connecting device, the ATM address (VPI / VCI) to the call processing unit 24 in the inter-network connecting device 13 is returned. . Even if the inter-network connection device makes this reply, for example, A
It may be performed by the RP server. Upon receiving this, the sending terminal again requests the connection processing (connection setting request ARP) to the call processing unit 24 in the inter-network connecting device 13.
Will be issued.

Incidentally, without issuing the "call processing request ARP",
A method of directly broadcasting the "connection setting request ARP" through a broadcast channel is also conceivable.

In this way, the call processing unit 24 in the inter-network connecting device 13 which has received the connection connection request, in each ATM-LAN, connects between the transmitting terminal and the inter-network connecting device, and the inter-network connecting device. By establishing an ATM connection between the terminals on the receiving side and setting the header conversion unit 26 appropriately, both ATM connections are connected and finally an ATM connection between both terminals is established. here,
When establishing an ATM connection in each ATM-LAN, the call processing units 91 and 9 in both ATM-LANs are established.
2 may be used.

(Method 2) Method of Relaying ARP by Network-to-Network Connection Device In this method, when the transmitting terminal device issues a "connection setting request ARP", the network-to-network connection device that receives this connection requests the connection. The setting request ARP is relayed. That is, the transmission-side terminal device indicates that the address (network layer address, mail address, or the like) of the reception-side terminal is a connection setting request (for example, in the case of performing this ARP by broadcasting, this is indicated in the broadcast cell type). Including) (connection setting request) A
Perform RP. Upon receiving this, the call processing unit in the inter-network connecting device recognizes that this connection setting request ARP is the connection setting request ARP over the inter-network connecting device and crosses this ARP over the inter-network connecting device. Next A
Relay to TM-LAN. This is, for example, the A
The ARP request cell for making the RP request is transferred to the next ATM-LAN.
It is performed by sending (relaying) to the. Also, in parallel with or before or after the ARP relaying, the ATM connection between the transmission side terminal and the inter-network connection device is set / established.

During this period, the ARP is currently sent to the sending terminal.
You may tell that you are inside.

When this ARP is completed, that is, when the ATM connection between the network connecting device and the receiving side terminal is established, this ATM connection (ATM connection between the network connecting device and the receiving side terminal) is transmitted. The ATM connection established between the side terminal device and the inter-network connection device is connected. In that case, this can be done by appropriately setting the header conversion unit in the network connection device. In this way, the ATM connection for the end-to-end connection between the sending terminal and the receiving terminal is
The connection connection is completed by notifying the sending terminal device of the VPI / VCI value of the connection.

As described above, ATM is performed by ARP relaying.
It should be noted that when a connection is established, a special call processing unit is not required in the inter-network connecting device, and it is sufficient if the ARP relaying function is simply provided. Therefore, this method 2 can be considered to be a special case of the above method 1.

Next, as a concrete example of Method 2, both ATM-
An example of the flow of the connection setting request across the inter-network connection device when the VP routing method is used in the LAN will be outlined.

For example, the case where the terminal A of the first ATM-LAN requests the setting of the ATM connection (end-to-end ATM connection) with the terminal B of the second ATM-LAN will be shown.

The terminal A of the first ATM-LAN designates the address of the terminal B (for example, the network layer address) as the address of the address resolution and sends the connection setting request ARP. In the inter-network connection device that receives this, for example, the call processing unit identifies that the terminal B that is the address resolution target of the connection setting request ARP exists in the second ATM-LAN, or makes a default. Select the second ATM-LAN that is the ARP destination defined in
The connection setting request ARP is relayed to the ATM-LAN (i.e., the connection setting request ARP is sent to the second ATM-LAN). At this time, the source address of the ARP cell may be rewritten and used as the address of the call processing unit in the inter-network connecting device.

In parallel with this, or before or after this, the call processing unit of the inter-network connecting apparatus operates the A between the transmitting terminal A and the inter-network connecting apparatus.
Secure TM connection. Specifically, the first AT
In the VPI value (VPI value = # P) assigned to itself (inter-network connection device) on the M-LAN side, an unused VCI value is appropriately selected (selected VCI value =
#Q), and this is defined as the ATM connection between the transmission-side terminal A and the inter-network connection device. During this time, the first A
It should be noted that the switch node (routing table) in the TM-LAN is not set at all.

In the second ATM-LAN, the ATM connection between the receiving side terminal B and the inter-network connection device is ARP.
Is established or address resolution is performed (that is, the inter-network connecting device obtains the ATM address from the inter-network connecting device to the receiving side terminal B. This ATM address value is V
PI value = # R, VCI value = # S), and an ATM connection between the network connecting device and the receiving side terminal B is defined.

The call processing unit in the inter-network connecting apparatus uses the header conversion function to convert the ATM connection between the transmitting side terminal A and the inter-network connecting apparatus and the ATM connection between the inter-network connecting apparatus and the receiving side terminal B into each other. By setting the table appropriately,
That is, (VPI, VCI) = (# P, #Q) and (VPI,
VCI) = (# R, #S) is defined to connect both ATM connections, and the transmitting terminal A
An end-to-end ATM connection between the receiver and the terminal B on the receiving side is established.

Here, the call processing unit in the inter-network connection device is AR
It should be noted that P relaying is performed and that the tables in the inter-network connection device are only set. That is, it is not always assumed that a special call processing unit exists in both ATM-LANs.

Regarding the end-to-end ATM connection established in this way, as a ARP response, (VPI, VCI) = in the call processing unit in the inter-network connection device.
(#P, #Q) will be returned to the transmitting terminal A as the resolution result. The transmitting terminal A is (VPI, V
CI) = (# P, # Q), when a cell is transmitted at the ATM address, the cell does not receive the termination of AAL or more on the way, and end-to-end communication is possible only with the receiving side terminal B and the ATM layer processing. This means that the end-to-end ATM connection has been established.

Information of the attribute of the communication to be connected (UPC parameter, QOS, etc.) may be added to the information part of the cell of the connection connection request ARP.

The above is A from the terminal on the transmitting side to the terminal on the receiving side.
It was a flow until the TM connection was established, but it is of course possible to establish an ATM connection from the receiving side terminal to the transmitting side terminal in parallel with this, and to enable bidirectional communication. In this case, the VCI value desired to be used in the reverse direction ATM connection (for example, the inter-network connecting device to the transmitting side terminal A or the receiving side terminal B to the inter-network connecting device) is added to the connection setting request ARP. You may leave it (this V for reverse direction ATM connection)
CI value is used).

Here, the first and second ATM-LAs are used.
Although the description has been made on the premise that the call processing units 91 and 92 are present in N, respectively, it is not always necessary that one or more call processing units are present in the ATM-LAN.
A configuration in which call processing is performed using the call processing unit in the M-LAN is also conceivable.

Next, a description will be given of the case where bandwidth management is performed for an ATM connection that crosses the inter-network connecting device, that is, when an appropriate QOS is required for the ATM connection.

In the case of the above (method 1), each ATM-
When setting the ATM connection in the LAN, the entity (which may be in the call processing unit) that manages the bandwidth and also manages the bandwidth of the ATM transmission line in the inter-network connecting device is in the inter-network connecting device. Band management is performed, and A in both ATM-LANs
Only when all of the band management units of the TM connection (which may be in the call processing units 91 and 92) and the band management units of the inter-network connection devices determine that the ATM connection can be established. It suffices to connect the ATM connections by appropriately defining the header conversion function in the inter-network connecting device and establish the ATM connections.

In the case of (method 2), after the ATM connection across the inter-network connecting device is established or when the ATM connection is established, the bandwidth management unit in both the ATM-LAN and the inter-network connecting device establishes the ATM connection. Queries the adequacy of the bandwidth management, and permits the use of the ATM connection via the bandwidth management (that is, maintaining the QOS above a certain level) when the permission is given. Here, the bandwidth management unit determines that the Q
When the use of the ATM connection holding the OS is not permitted, the fact that the bandwidth management cannot be secured is notified to the transmitting side terminal (and also to the receiving side terminal if necessary).
In this case, it should be noted that an ATM connection without band management is established. Here, in the case where the terminal side may use a connection in which band management is not performed, communication is started by the ATM connection, and when it is determined that communication is not possible in an ATM connection in which band management is not performed, The communication will be abandoned. In that case, the ATM connection disconnection request may be issued.

The processes described above are not limited to the connection setting request, and are almost the same when the connection setting / disconnection / change request is made.

As described above, by providing the call processing function in the network connecting device, the following advantages can be enjoyed.

(1) The processing of the ATM connection across the inter-network connection device requires information in both networks to be connected. By arranging the call / connection processing unit in the inter-network connecting device located between the respective networks and capable of knowing the information in the respective networks, it is possible to efficiently process the ATM connection across the inter-network connecting devices. Can be done on a regular basis.

(2) This call / connection processing unit can be accessed from each network connected to the inter-network connecting device. Further, this access can be performed without using an ATM connection that spans a plurality of networks.

(3) The call / connection processing unit in the inter-network connecting apparatus can be specialized in processing an ATM connection across the inter-network connecting apparatus.

(4) For ATM connections across networks, it is necessary to convert each ATM address system (VPI / VCI system) in the inter-network connection device. By providing the call / connection processing unit in the network connection device, the call / connection processing unit may include an element indispensable for address system conversion, such as the setting unit of the conversion table of the VPI / VCI system, or the like processing. It is possible to tightly connect with the part.

In the call processing method described in this embodiment, the call processing unit does not necessarily have to exist in the IWU, and a configuration in which it exists at an arbitrary position in the network is also conceivable. However, in this case, since the call processing unit needs to set the table in the IWU and the like, it is desirable that there is an ATM connection directly connected to the IWU.

Next, FIG. 10 shows another embodiment of the connection state of the ATM connection between the terminals in both ATM-LANs and the call processing unit 24 in the inter-network connecting device 13. In this embodiment, the call processing units 101 and 102 in each ATM-LAN.
And the call processing units 24 in the inter-network connection device 13 are connected by ATM connections. This ATM connection may be VP or VC.

In this case, the ATM connection connection request across the inter-network connection device 13 is first terminated by the call processing units 101 and 102 in the ATM-LAN, and the ATM connection requested here is the inter-network connection device. When the call processing units 101 and 102 recognize that the call processing is over the call processing unit, the call processing is relayed to the call processing unit 24 in the inter-network connecting device 13, and further, in the inter-network connecting device 13. Is relayed from the call processing unit 24 to the call processing unit in the ATM-LAN on the opposite side. In this process, both ATs
ATM connection in M-LAN is each ATM-L
Established by the call processing unit in the AN, and by properly setting the header conversion unit in the inter-network connection device, both ATMs
The connection is established, and as a result, an ATM connection across the inter-network connection device is established.

Here, in the call processing system of the form as shown in FIG. 10, a connection setting request from a terminal in the ATM-LAN, whether or not it is a request closed in its own ATM-LAN, is transmitted between the networks. This is a method in which calls are always sent to the call processing units 101 and 102 in the ATM-LAN, regardless of whether they extend over connection devices. Even in this system, ATM-LA
The call processing unit in N and the call processing unit 24 in the inter-network connection device 13
It should be noted that the ATM connection that connects the two does not extend across the CLSF processing unit or the inter-network connection device as in the previous embodiment, that is, does not extend over the ATM-LAN.

By arranging the call processing units in this manner, the call processing units 101 and 10 in the ATM-LAN are arranged.
It should be noted that only the configuration information of its own ATM-LAN needs to be placed in the area 2, and only the call processing unit in the inter-network connection device needs to have the configuration information of both ATM-LANs. is there. Here, the call processing unit 1 in the ATM-LAN
It is possible to make a rule that 01 and 102 are relayed to the call processing unit in the inter-network connecting device when the arrived ATM connection setting request is not a request closed in the own ATM-LAN.

Next, FIG. 11 shows an example in which the call processing unit does not exist in the inter-network connecting device. The setting of the ATM connection across a plurality of ATM-LANs in such a form is performed by the call processing unit 11A in the first ATM-LAN 111.
Then, it is carried out by cooperative distribution with the call processing unit 11B in the second ATM-LAN 112. That is, for example, a plurality of ATM-LAs from terminals in the first ATM-LAN
A request for setting an ATM connection extending over N is first passed to the call processing unit 11A in the first ATM-LAN,
The call processing unit 11A recognizes that the request spans a plurality of ATM-LANs, and sends this request to the second A-LAN.
Relaying to the call processing unit 11B in the TM-LAN 112, and thereafter, the plurality of call processing units are cooperatively distributed and AT
Establish M connections. Here, it should be noted that the establishment of the ATM connection in the inter-network connecting device, that is, the setting of the header conversion unit in the inter-network connecting device is also the responsibility of either call processing unit. Further, for example, a permanent ATM connection (either VP or VC is possible) between both call processing units.
Although connected by the ATM, an ATM connecting the call processing units
It should be noted that the connection extends between both ATM-LANs. Further, in this case, basically, all the call processing units need to internally have information regarding the configuration of the adjacent ATM-LAN.

As described in detail above (excluding the example of FIG. 11), the cells of the C-plane relating to the connections that should span a plurality of networks are basically call processing units for LAN-to-LAN connection (in the present embodiment, the network). It is terminated at the call processing unit in the inter-connector. Here, the cells of the M plane can also be configured to be terminated in the inter-network connection device. In this case, the network management unit is arranged in the inter-network connection device. The network management unit arranged in the inter-network connection device can collectively manage, hold, or easily prepare the management information of the ATM-LAN ahead of the network management unit. It is possible to significantly reduce the addition and the like when exchanging and acquiring the network management information when configuring the LAN in a hierarchical manner (it is possible to terminate before and after the inter-network connecting device).

[0181] Further, the inter-network connection device is an ATM of another vendor.
When located between the LAN and the LAN, a protocol conversion unit (that is, a conversion unit of the ATM-LAN protocol for each vendor) may be included therein.

A so-called broadcast channel broadcast in the ATM-LAN is basically terminated in this inter-network connecting device. This can be easily realized by setting in the header conversion unit in the inter-network connecting device that a certain fixed broadcast cell is not transmitted to the next ATM-LAN and is discarded in the header conversion unit. Is.

Note that VPI = all 1 is a broadcast cell,
If the attribute of the broadcast cell is determined by the VCI value, a certain broadcast cell, that is, a broadcast cell having a certain VCI value is discarded in the header conversion unit, and another broadcast cell (other With respect to a broadcast cell cell having a certain VCI value, it is possible to easily perform relaying of the broadcast cell by sending the broadcast cell to the next LAN broadcast channel after header conversion as necessary. is there. Also, with respect to cells received via the broadcast channel, it is possible to easily broadcast via the broadcast channel in the next ATM-LAN by appropriately setting the header conversion unit. A diagram summarizing these is shown in FIG.

(Second Embodiment) Next, FIG. 13 shows an ATM network according to a second embodiment of the present invention. As shown in the figure, the ATM network of this embodiment is the first ATM-
LAN 131, second ATM-LAN 132, third A
It comprises a TM-LAN 133 and an inter-network connection device (IWU) 134.

First ATM-LAN 131, second AT
The M-LAN 132 and the third ATM-LAN 133 are local area networks that are operated by the ATM system as in the first embodiment. Also, each A
The address system is independent in the TM-LAN. AT
When there is information to be transmitted, the terminal device or node in the M-LAN stores the information in the ATM cell regardless of whether the destination is in the ATM-LAN or not. The ATM-header
Send to LAN.

FIG. 14 shows a diagram of the internal structure of the inter-network connecting device 134. In this way, the inter-network connection device 134 is
M switch 141, CLSF processing unit 142, call processing unit 1
43, IWU management unit 144, input processing units 14A, 14
B, ..., Output processing units 14X, 14Y ,.

The inter-network connection device 134 is located between two or more ATM-LANs and has a plurality of ATM-LANs.
It has a function of controlling internetworking (connection between LANs) of the LAN.

The input processing section 14A, ...
The header value (for example, VPI / VCI value) of the cell is analyzed (the conversion is performed if necessary), and a routing tag for routing the cell in the ATM switch is newly added to the input cell. Have a function.

The ATM switch 141 is an N-input M-output (N, M is a positive number, for example, N = M = 8) ATM switch. The cell is routed according to the routing tag given to the cell. It may have a broadcast function and a multicast function internally.

The output processing units 14X, ... Have a function of deleting a routing tag from an ATM cell arrived via an ATM switch, and a function of converting the value of the ATM cell header if necessary.

This ATM cell header conversion function is a function necessary for either the input processing unit or the output processing unit. The input processing unit and the output processing unit control the connection between the switch node in the LAN, the terminal device, and, if necessary, another network connecting device, which are adjacent to each other.

The function of the CLSF processing section 142 is the connectionless service function (Connection Less Service Function).
on). This function is basically the CL of the first embodiment.
Since this is similar to the SF processing unit 23, detailed description will be omitted.

The call processing unit 143 basically sets and disconnects an ATM connection across the inter-network connecting device 134.
It has the function of changing and managing, and is basically the first
The function is similar to that of the call processing unit 24 of the embodiment. Therefore, detailed description is omitted.

The IWU management unit 144 is connected to the inter-network connection device 1
It has a function of managing and controlling 34. Network connection device 1
It is assumed that each module in 34 is connected to each bus (not shown), and control such as change of set value of each module from the IWU management unit 144 is performed through this bus.

Instead of exchanging information between the modules through the bus as described above, this may be done by placing the information on the ATM cell and exchanging the cell between the modules.

Further, in the present embodiment, various processes in the IWU are performed separately (that is, the CLSF processing unit uses CL.
It is also possible to perform all or some of these processes in the same CPU / MPU in the SF process dedicated module, and the call process is performed in the call process dedicated module.

Next, FIG. 15 shows the first ATM-LAN 13
1, second ATM-LAN 132, third ATM-LA
9 shows an embodiment of a node / terminal configuration inside N133. The first ATM-LAN 131 includes three switch nodes 151, 152, 153 and terminals 15A, 15B, 15C, 15D connected to them. The second ATM-LAN 132 has two switch nodes 15
4, 155 and terminals 15E, 15 connected to them
It consists of F and 15G. The third ATM-LAN 133 is
It is composed of two switch nodes 156 and 157 and terminals 15H, 15I and 15J connected to them. The function of the switch node is similar to that of the first embodiment.

Next, FIG. 16 shows the A between the terminals in each ATM-LAN and the CLSF processing unit in the inter-network connection device 134.
An embodiment of a TM connection connection state is shown. Here, for simplification, wiring between terminals / switch nodes and between switch nodes / inter-network connecting devices is omitted. Also, other components such as a call processing unit and a header conversion unit in the inter-network connecting device and a switch node in the ATM-LAN are omitted in the drawing.

In this way, each terminal device and the inter-network connection device 1
The CLSF processing units 142 in 34 are connected by ATM connections (VP or VC). This A
Similar to the first embodiment, the TM connection is a connection that is not subject to band management. A that connects this terminal device to the CLSF processing unit 142 in the network connection device 134
It should be noted that the TM connection does not extend over the inter-network connection device, that is, does not extend over the ATM-LAN, as in the first embodiment.

When the terminal device wants to deliver the datagram via the inter-network connecting device 134, that is, outside the own ATM-LAN, this is carried out by the same process as in the first embodiment. The following is a brief description.

Regarding the delivery of the datagram across the inter-network connecting device 134, the CLSF in the inter-network connecting device 134 is used.
It will be delivered via the processing unit 142. That is, AT
The datagram converted into M cells is sent to the CLSF processing unit 142. Here, the terminal / node in the ATM-LAN sends the datagram to the CLSF processing unit 142.
Since the approach (ARP) until the terminal device knows that it should be sent to the terminal device is the same as that in the first embodiment, its details are omitted. Similar to the first embodiment, the ARP for the delivery of the datagram across the inter-network connection device is performed, and the terminal device that sends the datagram thereafter converts the datagram into ATM cells and then When the destination is a destination that crosses the inter-network connection device, the ATM address (V
PI / VCI), and use CL in the network connection device.
It is sent to the SF processing section. The CLSF processing unit in the inter-network connection device sets this once in the network layer or CL.
A that is connected to the destination after terminating at the layer and analyzing the destination address (after making ATM cells again if necessary)
The TM connection will be selected appropriately and the datagram will be delivered through it.

Here, also in this system, the same advantages as the advantages of the CLSF processing unit in the inter-network connecting device in the first embodiment can be enjoyed.

Next, FIG. 17 shows an AT between the terminals in each ATM-LAN and the call processing unit 143 in the inter-network connection device 134.
An embodiment of the M connection connection state is shown. here,
For simplification, wiring between terminals and switch nodes and between switch nodes and network connection devices is omitted. Further, other components such as a CLSF processing unit processing unit and a header conversion unit in the inter-network connecting device are also omitted in the figure. Also, both A
Call processing units 171, 172, 173 are added to the TM-LAN.

In this way, each terminal device and the call processing unit 143 in the inter-network connecting device 134 are connected by the ATM connection (VP or VC). Note that the ATM connection that connects this terminal device and the call processing unit 143 in the inter-network connection device 134 does not extend over the inter-network connection device, that is, does not extend over the ATM-LAN, like the CLSF processing unit. is necessary.

In this case, it should be noted that only the call processing unit in the inter-network connecting device has all the configuration information of each ATM-LAN.

If the terminal device / node in the ATM-LAN wants to establish an ATM connection across the inter-network connecting device 134, this call processing unit 143 is used. Basically, it is the same as the first embodiment, but there are some differences, so a brief description will be given.

First, description will be made regarding a case where only a simple connection is required.

(Method 1): When the terminal makes a connection connection request to the call processing unit in the inter-network connection device.

This case is based on the first embodiment. Therefore, detailed description is omitted.

(Method 2): A method in which the inter-network connection device relays ARP.

Also in this method, as in the first embodiment,
When the terminal device on the transmitting side issues a "connection setting request ARP", the inter-network connecting device that receives this relays the ARP, but the target address of the ARP is a plurality of ATM-connected to the inter-network connecting device 134. It differs from the first embodiment in that the ATM-LAN to which the LAN belongs is analyzed and then the ARP is relayed only for the ATM-LAN. That is, this call processing unit has an internal database (correspondence table between connected LAN and network address, domain name, etc.)
(Resolution at the network level), and the ATM / LAN found there, the terminal /
Resolution will be applied at the node level.

Of course, the network level resolution may not be performed in the inter-network connecting device, and ARP may be relayed to all ATM-LANs connected to the inter-network connecting device. ATM-LAN connected with
On the other hand, the ARP may be sequentially performed until the ARP is completed (for example, from the smallest port number of the switch).

Note that when bandwidth management is performed for an ATM connection that crosses the inter-network connection device, that is, an appropriate QOS is used.
Is required for the ATM connection, the detailed description is omitted because it conforms to the first embodiment.

The above-described process is not limited to the connection setting request, and is almost the same when a connection setting / disconnection / change request is made.

Here, also in this system, it is possible to enjoy the advantages of the call processing unit in the inter-network connecting apparatus in the first embodiment.

Further, the call processing unit 143 does not necessarily use the IWU1.
It may not be located within the network 34, but may be located anywhere within the network.

Next, in FIG. 18, A between the terminals in each ATM-LAN and the call processing unit 143 in the inter-network connecting device 134 is shown.
9 shows another embodiment of a connection state of a TM connection. Call processing units 181, 182, 183 in each ATM-LAN
And the call processing units 143 in the inter-network connecting device 134 are connected by ATM connections (VP or VC). Also in this case, similarly to FIG. 10 of the first embodiment,
An ATM connection connection request across the inter-network connection device 134 is first made by the call processing units 181, 18 in the ATM-LAN.
ATMs required here, terminated at 2,183
When the call processing unit 181, 182, 183 recognizes that the connection is across the network connecting device,
The call processing unit is relayed between the call processing unit 143 in the inter-network connecting device 134, and further, the inter-network connecting device 134.
The call processing unit 143 in the inside discriminates which terminal / node in the ATM-LAN is the connection connection request, and based on the discrimination result, the corresponding ATM-LAN.
It is relayed to the call processing part of. In this process,
ATM connection in each ATM-LAN is each AT
The ATM connection is established by the call processing unit in the M-LAN, and by properly setting the input processing unit or the header conversion unit in the output processing unit in the inter-network connecting device, resulting in the connection between both ATM connections. AT across connected devices
M connections are established.

When the call processing unit 143 in the inter-network connecting device 134 relays the arrived connection connection request across the inter-network connecting device to the call processing unit in the ATM-LAN, Instead of analyzing which ATM-LAN call processing unit the call processing unit in the inter-network connection device relays this (if necessary,
All connected ATM-Ls (except the call processing unit in the ATM-LAN where the connection setting request is issued)
It is also possible to adopt a method of broadcasting this to the call processing unit in the AN or a method of sequentially sending inquiries to these.

Similar to the first embodiment, in the call processing system as shown in FIG. 18, the connection setting request from the terminal in the ATM-LAN is the own ATM-L.
The call processing unit 1 in the ATM-LAN, whether it is closed in the AN or across an inter-network connection device
81, 182, 183. Also in this system, the ATM connection connecting the call processing unit in the ATM-LAN and the call processing unit 143 in the inter-network connection device 134 is also the CLSF processing unit or the inter-network connection device as in the previous embodiment. It is important to note that it does not extend across ATM, that is, between ATM and LAN.

By arranging the call processing units in this manner, the call processing units 181 and 18 in the ATM-LAN are arranged.
It should be noted that only the configuration information in the own ATM-LAN needs to be placed in the Nos. 2 and 183, and only the call processing unit in the inter-network connecting device needs the configuration information regarding both ATM-LANs. is necessary. Here, the call processing units 181, 182, and 183 in the ATM-LAN are relayed to the call processing unit in the inter-network connection device when the arrived ATM connection setting request is not a request closed in the own ATM-LAN. It is also possible to make a rule that it is good.

Next, FIG. 19 shows an example in which the call processing unit does not exist in the inter-network connecting device. Also in this case, as in the first embodiment, a plurality of ATM-LAs in such a form are used.
ATM connection across N is the first AT
A call processing unit 19A in the M-LAN 191 and a second ATM
-Call processing unit 19B in LAN 192 and a third ATM-L
This will be performed by cooperative distribution with the call processing unit 19C in the AN 193. That is, for example, from a terminal in the first ATM-LAN to a terminal in the second ATM-LAN,
A request for setting an ATM connection across a plurality of ATM-LANs is first made by the call processing unit 1 in the first ATM-LAN.
9A, the call processing unit 19A recognizes that the request crosses a plurality of ATM-LANs,
This request is sent to the call processing unit 1 in the second ATM-LAN 192.
After that, the plurality of call processing units cooperatively disperse and establish ATM connections. Here, it should be noted that the establishment of an ATM connection in the inter-network connecting device, that is, the setting of the header conversion unit in the inter-network connecting device is also the responsibility of any of the call processing units. The call processing units are connected by, for example, a permanent ATM connection (either VP or VC may be used). The ATM connection connecting the call processing units is both ATM-
Note that it spans LANs. Further, in this case, basically, all the call processing units need to internally have information regarding the configuration of the adjacent ATM-LAN. Also, a plurality of A's can be connected to one network connection device.
In the situation where the TM-LAN hangs, each ATM-LA
It is necessary to basically establish a permanent connection between the call processing units in N in a mesh form.

As described above in detail, also in the second embodiment, as in the first embodiment (except for the example of FIG. 19), the C-plane cells relating to the connections that should span a plurality of networks are basically The call processing unit for LAN-to-LAN connection (the call processing unit in the inter-network connecting device in this embodiment) is terminated. Further, the M plane cells can also be configured to be terminated in the inter-network connection device, as in the first embodiment. Further, when the inter-network connecting device is located between ATM-LANs of other vendors, a protocol conversion unit (that is, a conversion unit for ATM-LAN protocol for each vendor) may be included therein. . In addition, the broadcast channel in the ATM-LAN is basically terminated in this inter-network connecting device as in the first embodiment.

(Third Embodiment) Next, FIG. 20 shows an example of a method of constructing a large-scale ATM network as a third embodiment. This large-scale ATM network includes an ATM backbone network 201, a first ATM-LAN 202, a second ATM-LAN 203, and a third ATM-LAN 20.
4. An ATM backbone network and inter-network connection devices 20A, 20B and 20C between each ATM-LAN. These ATM-LANs can have a hierarchical network structure via the ATM backbone network 201.

The ATM backbone network 201 consists of ATMs.
-A network that connects LANs to each other and interfaces with a public network (not shown). The internal architecture is not particularly limited, but it is a flexible, expandable, and highly reliable network that can take various architectures such as ring / star / bus / tree / mixture thereof. ATM-LAN 202, 203, 20
4 is the same as in the first and second embodiments.

The inter-network connection devices 20A, 20B, 20C are
2 is almost the same as the inter-network connection device 13 in FIG. 2 except that it controls internetworking between the ATM backbone network and the ATM-LAN. However, in the ATM backbone network, the ATM-LAN is used from the viewpoint of ensuring its reliability. Because the traffic management is stricter than that of the above, the policing mechanism is attached to the output interface to the backbone network side of the inter-network connection device, and the specified traffic conditions are complied with. Other fine ATMs
-A major difference from the inter-network connection device 13 of Fig. 2 is that a protocol conversion mechanism between the LAN and the ATM backbone network is provided.

Here, for example, the ATM backbone network is a network under the control of the management department of the whole company or university, or the management department of the whole establishment, whereas the ATM-LAN is each department, section, research of the company or university. LAN laid in each room
Is. Compared with the current situation, it can be considered that the ATM backbone network corresponds to the current telephone network (PBX network) and the ATM-LAN corresponds to the current computer communication LAN. The large-scale network according to the present embodiment has a telephone network and a computer network as a hierarchical network.
It is considered to be a network integrated by the M method. Further, it may be assumed that the ATM backbone network is a network that is deployed on a nationwide scale via a private line of a public network.

FIG. 21 shows the internal structure of the ATM-LAN in this large-scale network. First ATM-LA
N202 is the three switch nodes 211, 212, 2
13 and terminals 21A, 21B, 21 connected to these
It consists of C and 21D. In addition, the second ATM-LAN20
3 comprises two switch nodes 214 and 215 and terminals 21E, 21F and 21G connected to them. The third ATM-LAN 204 has two switch nodes 216 and 217 and a terminal 21 connected to them.
It consists of H, 21I and 21J. The function of the switch node is similar to that of the first embodiment.

Next, details of the datagram delivery method in the ATM-LAN in the large-scale network of this embodiment will be described. First to third ATM-LAN2
Since the datagram delivery method is the same for each of Nos. 02 to 204, the first ATM-LAN 202 is representatively shown.
Will be described as an example.

In the first ATM-LAN 202,
Unique VPI values are assigned to all nodes, IWUs, and terminal devices inside the LAN, respectively. That is, when a cell originated from any other node / IWU / terminal has the VPI value in the VPI field of its ATM cell header, the cell is always routed to the corresponding node / IWU / terminal. It It should be noted here that the switch node and the inter-network connection device are also assigned unique VPI values in the LAN.

For example, as shown in FIG. 22, node / IWU /
When one VPI value is assigned to each terminal, “VPI value = # A” is set, and a cell transmitted from an arbitrary terminal / node is always assigned to the terminal 21A regardless of the number of VCI values. Routing, ie delivered. Also, in order for the cell to be routed in this way, A
The routing table of the switch node in the TM-LAN is set.

With this setting, the ATM
-It is equivalent to that ATM connections are preliminarily established in a mesh shape (end-to-end) between nodes / IWUs / terminals belonging to a LAN. That is, any terminal / I
From the WU / node (called the sending terminal) to any terminal /
When performing communication with an IWU / node (referred to as a receiving side terminal) (when transmitting a cell), if the VPI value (ATM cell header value) assigned to the receiving side terminal is used, the cell is transferred to the receiving side terminal. Is routed. This means that an ATM connection from an arbitrary transmission side terminal to an arbitrary reception side terminal is set up in a mesh shape (there is no guarantee of QOS) (VP routing method).

The format of the ATM cell header in the ATM-LAN of this embodiment is in accordance with the format of the UNI (user / network interface) cell in the CCITT recommendation. VPI value is ATM-L
Since it is assigned to the constituent elements (node / IWU / terminal) configuring the ATM-LAN so as to be unique in the AN, the upper limit of the total number of nodes / IWU / terminals in the ATM-LAN is 256. Limited This is because the VPI area has only 8 bits. In this embodiment, the upper limit of the total number of nodes / IWUs / terminals in the ATM-LAN is even smaller as described later.

Here, the switch is set in the switch node in order to implement the VP routing method. That is, when an appropriate VP is set in the ATM cell header and the cell is transmitted, the cell is routed to the intended receiving terminal. Despite this, there may be a case where the transmission side terminal does not recognize the ATM address (VPI value) of the reception side terminal. In this case, it is assumed that the sending terminal recognizes the network layer address of the intended receiving terminal (or may be the physical address value of the communication board).

In such a situation, in the existing LAN (eg Ethernet), the physical address (MAC address, eg Ethernet address) is known even though the network layer address (eg IP address) of the receiving side terminal is known. If you don't know, respond. In an existing LAN, in such a case, a protocol for resolving a physical address from a network layer address (address resolution protocol, AR
P) will work.

Similarly to this, the ATM-LA of this embodiment is
Even in N, the ATM layer (V
ARP to obtain (resolve) PI value)
Express to do.

The ARP method in the case where the receiving side terminal is in the same ATM-LAN as the transmitting side terminal will be described below. First, the following two methods can be considered as this method.

(Method 1): Direct ARP of sender terminal-receiver terminal The sender terminal knows the network layer address (for example, IP address or E.164 address) of the receiver terminal, but this address is It is not known which ATM address (specifically, VPI / VCI value) corresponds to. In this case, the transmission side terminal has previously set the ATM-
ARP is performed through the broadcast channel defined in the LAN. Although the details will be described later, there are several types of ARP, and this ARP is the “datagram transmission request ARP” therein.

Here, the broadcast channel is
It is an ATM connection capable of broadcasting a transmitted cell from an arbitrary transmission side terminal to all nodes / IWUs / terminals belonging to the ATM-LAN. In this ATM-LAN, for example, "VPI value = all When the cell of "1" is transmitted, the cell is recognized as a broadcast cell by the network, and the cell is all the nodes / IWUs belonging to the ATM-LAN.
/ Delivered to the terminal. Here, the cell transmitted as the broadcast cell may or may not be delivered to the terminal itself which has transmitted the cell.

FIG. 23 shows an example of the format of a cell which makes a datagram transmission request ARP. In this way, the source address (Sou
rceAddress), destination address
, Broadcast cell type, and ARP type are included at least.
The source address includes the network layer address type, the network layer address of the sending terminal, and the AT
In the M-LAN, the VP assigned to the sending terminal
I value is included.

Here, the network layer address type indicates which network layer address is the network layer address of the transmitting terminal subsequently included in this area (which network layer protocol address). Area. For example,
As shown in FIG. 24, LLC + (SNAP (SubNetworkAttatc
hment Point) or NLPID (Network Layer Protocol
ID)) can be used for identification. In addition, as the network layer address type,
Request For Comments (RFC) 1134 P
The same protocol type as PP (Point to Point Protocol) may be used.

Also, the VPI assigned to the sending terminal
As described above, if a value is used, cells can be delivered from all the nodes / IWUs / terminals belonging to the ATM-LAN to the “transmission side terminal” (VP routing method). That is, this value informs the ATM address of the ATM-LAN of its own.

The destination address includes the network layer address type and the network layer address of the receiving terminal. Since the network layer address type and the network layer address of the receiving side terminal have the same relationship with the same type and the same address of the source address, detailed description thereof will be omitted.

[0243] The broadcast cell type is a field in which the meaning of the broadcast cell is described. The specific "meaning of broadcast cell" is, for example, "datagram transmission request ARP" or "connection connection request A".
"RP" (meaning described later), "broadcast" (cells carrying information required by all nodes / IWUs / terminals in the ATM-LAN, such as routing information. This type of cell basically covers all Node / IWU / terminal receives and processes). 6 for identification of broadcast cell type
As a bit coding method, for example, "0000
00; datagram transmission request ARP "," 00000
1; connection connection request ARP ","000010;
Broadcast ”and so on.

[0244] The ARP type means that the broadcast cell is ARP.
If it is (“datagram transmission request ARP” or “connection setting request ARP”), is the ARP “ARP request” (for example, ARP type value =
0) and whether it is an “ARP response” (the same = 1)).

As a 2-bit coding method for identifying the ARP type, for example, "00; ARP request",
"01; ARP response", "10; RARP request", "1"
1; RARP response ”or the like. here,
The "ARP request" in ARP is an AR used when inquiring the ATM address (VPI value etc.) of the other side.
The type of P cell, "ARP response", is an ARP that returns an ATM address as a reply to the "ARP request".
This is the type of cell.

Note that an error correction code such as parity or CRC may be added to this ARP cell. This error correction code is preferably inserted at the end of the cell in order to facilitate pipeline processing of the cell.

Further, it is desirable that this ARP cell is completed in one cell without extending over a plurality of cells. This is because when the ARP cells extend over a plurality of cells, it is necessary to reassemble the information over the plurality of cells, which leads to a complicated process. That is, a certain information packet is converted into an ATM cell,
When transferring this through the broadcast channel, the receiving terminal first recognizes that it is a broadcast cell addressed to itself by referring to the destination address included in the cell, and then by referring to the source address and transmitting source. Is determined, cell reassembly is performed for each source address, and an information packet is obtained. Therefore, when the broadcast cell is received by being multiplexed from a plurality of transmission side terminals, the reception side terminal individually reassembles the information packet for each set of the destination address and the source address. The function to do is required. This means that realization of the analysis / processing function of the broadcast cell, especially hardware, requires a large cost. On the other hand, if the broadcast cell is completed by one cell, reassembly becomes unnecessary, and the processing for each cell may be sequentially performed, which facilitates the realization. This is a situation common not only to the ARP cell but to all broadcasting cells.

By the way, when the transmitting terminal performs ARP,
The broadcast cell is transmitted to the ATM-LAN using "datagram transmission request ARP (ARP request)". In that case, the ATM address field of the partner address contains unintentional data. The protocol may be defined in this way. All the nodes / IWUs / terminals belonging to the ATM-LAN receive this broadcast cell, identify the broadcast cell type, and identify that the broadcast cell is “datagram transmission request ARP (ARP request)”, Furthermore,
Whether or not this is the ARP addressed to itself (the ARP
Whether the cell's destination address includes its own address). If the cell is a "datagram transmission request ARP (ARP request)" addressed to itself, the ATM address of the sender terminal requesting the ARP (the VPI assigned to itself) In order to notify the value), a reply cell (ARP response) including its own ATM address (VPI value) is sent. This reply may be sent using the broadcast channel from the receiving terminal, but in the present embodiment, the transmission included in the “datagram sending request ARP (ARP request)” cell is taken into consideration in consideration of the communication resources of the network. The ATM address (VPI value) of the side terminal is set to the ATM of the reply cell (ARP reply cell)
The response is performed by using the address (VPI value). In these cases, in the response cell, the address of the sending side terminal (the terminal that made the ARP response), the address of the receiving side terminal (the terminal that made the ARP inquiry), and the broadcast cell type (using the broadcast cell AR when replying)
P type is entered. In this way, ARP inquiry (AR
Compared with (P request), the source address and the recipient address are exchanged.

Here, when the ARP response is made without using the broadcast channel, that is, the ARP response is
To the sending terminal that made the inquiry
A case will be described where an ATM connection at a point (an ATM connection by the VP routing method using the VPI value of the transmission side terminal) is used.

The VCI value used when replying to (the ARP of) the broadcast channel such as an ARP response is predetermined such as "VCI value = 0". As described above, the payload (48 octets) of the cell having “VCI value = 0” has the same format as the broadcast cell (see FIG. 25). By doing this, the payload cell type,
Since the information such as the ARP type, the sender address, and the other party's address is included, the “sending terminal (terminal that made the ARP request)” receives the ARP response and this is “the ARP response to the ARP request issued by itself. Can be recognized.

ATM / LAN internal node /
The ARP flow between the IWU / terminals is summarized in FIG.
As shown in this figure, the node / IWU / terminal that received the ARP request not addressed to itself is the cell (ARP request cell)
Can be discarded.

Note that the other terminals sequentially update / learn the address table (correspondence table between L3 address and VPI) in the own terminal by referring to these ARP cells not necessarily related to the own terminal. Good.

(Method 2): When an ARP server is used, the network layer address in the ATM-LAN and A
At least one server (ARP server) that manages and recognizes the correspondence with the TM address (VPI value) exists in the ATM-LAN, or even if it does not exist, the ATM-LAN
All nodes / IWUs / terminals belonging to the LAN are
When the method of accessing the server is recognized, an arbitrary terminal makes a query to the ARP server in order to perform resolution from the network layer address to the ATM address (VPI). However, the ARP server is not shown in FIG.

The transmitting terminal that makes the ARP request sends the ARP request cell through the broadcast channel, or
The VPI value addressed to the RP server is set in the ATM cell header (at this time, for example, VCI = 0. The reason is (method 1).
Same as the above), and sends the ARP request cell to the ARP server.

It should be noted, however, that if the ATM address (VPI value) of the ARP server is unknown, it is necessary to resolve this address. Here, when the resolution of the address of the ARP server is performed, the ARP channel is transmitted through the broadcast channel.
Address resolution may be performed from the network layer address of the server to the ATM address.
If the network layer address of the RP server is unknown, the AR indicates that the broadcast cell type is an ARP request cell.
The P server may autonomously recognize and respond to this. Also, this may be done using a process server or the like.

The ATM address of the ARP server is
Even if predetermined by default (ATM-L
AN is uniquely determined) Good.

The ARP server that receives the ARP request (datagram transmission request ARP) in this way
When the resolution destination of the P request is a node / IWU / terminal in the ATM-LAN, the VPI value corresponding to the resolution destination is returned as an ARP response. This ARP response may be performed through a broadcast channel as in (method 1), or may be performed using a point-to-point ATM connection to the transmitting terminal that has made the ARP request.

As described above, the ARP server is a single A
Not only one form in the TM-LAN but also a plurality of forms in the same ATM-LAN, or only one form in a plurality of ATM-LANs, the plurality of ATMs
-It may be configured to be accessible from the LAN.

The above embodiment is the address resolution method in the case where the receiving side terminal is in the same ATM-LAN as the transmitting side terminal. Therefore, an address resolution method in the case where the receiving side terminal is present in an ATM-LAN different from the transmitting side terminal will be described.

Basically, A in the embodiments so far.
In the TM network, for a datagram delivery across a plurality of ATM-LANs, that is, a datagram delivered across an inter-network connection unit (IWU), the CLSF processing unit terminates the ATM connection once, and the datagram is terminated. Receives the processing of the network layer address (network layer processing or CL layer processing).

Therefore, when the address resolution destination (reception side terminal having the network layer address) belongs to a different ATM-LAN from the viewpoint of the transmission side terminal, it is the "datagram transmission request ARP". In the ARP response to the ARP request, the address resolution result is C in the inter-network connection device.
VPI / VCI of ATM connection to LSF processing unit
It must be a value or ATM address.

Here, "datagram transmission request ARP"
The distinction between "and" connection connection request ARP "will be described. In the "datagram transmission request ARP", if there is a datagram to be transmitted (which is an ATM cell) (only the network layer address of the datagram to be transmitted is known and the ATM address is unknown), "ARP Request this resolution as "request". On the other hand, the "datagram sending request ARP" is a response that indicates what kind of ATM address can be used to deliver the datagram to a desired receiving terminal. Here, the delivery destination delivered by the ATM address value returned as the resolution result is not always the receiving side terminal.
For example, the destination delivered by the ATM address value is CLS.
This is the case for the F processing unit.

On the other hand, "connection setting request AR
P "is an AR requesting an ATM connection directly connected to the receiving terminal as an address resolution result.
P. That is, the receiving side terminal is the same ATM as the transmitting side terminal.
-Using the ATM address value that is the resolution result whether or not it is in the LAN, the ATM connection indicated by the ATM address is in the middle (for example, IW).
It is an ARP requesting a state in which it is connected to the receiving side terminal by an end-to-end ATM connection without being terminated by a U or a CLSF processing unit). Such ARP is similar to the connection setting method defined by the signaling procedure discussed in CCITT. However, when setting up the connection, bandwidth management (bandwidth reservation) is performed in this embodiment.
The overhead such as
The end ATM connection is set (in the sense that a table is set in the switch node), and if the ATM address is used, it only guarantees that end-to-end communication can be performed through the ATM connection. It is important to note that QOS and other guarantees are not guaranteed. If this ARP (connection setting request ARP) is used, an ATM connection coupled end-to-end can be obtained. Therefore, QOS (Quali) can be established between both terminals without going through a call setting server or the like.
ty Of Service) and communication attribute negotiation.

Next, the receiving terminal is different from the transmitting terminal A
The address resolution method (“datagram transmission request ARP”) when it exists in the TM-LAN will be specifically described. Also in this case, the following two methods can be considered.

(Method I): Sending side terminal-CLS in IWU
Direct ARP of F processing unit Basically, the receiving side terminal is the same ATM-L as the transmitting side terminal.
According to (Method 1) when existing in AN. That is, the network layer address of the receiving terminal (or the physical address of the communication board, etc.) is known, but when it is not known which ATM address this address corresponds to, the transmitting terminal preliminarily detects the ATM- ARP through a broadcast channel defined in the LAN
Is a method of performing.

The difference from the above (Method 1) is that the ARP is
If the destination terminal of the destination (datagram transmission request ARP) belongs to an ATM-LAN different from that of the sender terminal (if the datagram cannot be delivered without crossing the network connection device), the ARP It is the point that the inter-network connection device returns the response.

The inter-network connection device is an AT to which the transmitting terminal belongs.
By knowing the network layer addresses of all the nodes / IWUs / terminals in the M-LAN, it is possible to recognize that the receiving side address included in the ARP request does not exist in the ATM-LAN. In this case, the inter-network connection device acts as a default router and its ATM address value (V
The PI value) may be sent as an ARP response.

[0268] Further, it may be so arranged that an ARP response is made after confirming the existence of the receiving side terminal having the receiving side address included in the ARP request on the opposite side across the network connecting device. .

In addition, some routing protocol is I
Operating between WUs or between CLSF processors,
The routing information may be exchanged, and the ARP response may be performed based on the routing information.

The other points are almost the same as (Method 1) in the case where the receiving side terminal is in the same ATM-LAN as the transmitting side terminal. In this case, if the received broadcast cell is a datagram transmission request ARP, the add / drop function in the inter-network connecting device can perform an internal ARP process on the received broadcast cell (the LSF processing unit in this embodiment). ) Need to be dropped. For example, when the received broadcast cell is “connection setting request ARP”, this is dropped to the internal call processing unit.

Further, the CLSF processing section grasps the network layer address of the node / IWU / terminal belonging to each ATM-LAN connected to the inter-network connecting device as described above, and the receiving side address included in the ARP request is the AR.
It is necessary to analyze whether or not it is in the same ATM-LAN as the sending terminal that issued the P request, and generate an ARP response if it is not, and send an ARP response cell to the sending terminal. Is.

It is also possible to use a subnet mask or the like to consider whether or not the request is addressed to its own subnet.

As described above, the CLSF processing section has a datagram relaying function, an address resolution function, and a routing information processing function. The address resolution function and / or the routing information processing function may be provided separately from the CLSF processing unit.

(Method II): When an ARP server is used Basically, the receiving side terminal is the same ATM-L as the transmitting side terminal.
According to (Method 2) when existing in AN. That is, the network layer address in the ATM-LAN and A
There is a server (ARP server) that manages and recognizes the correspondence with the TM address (VPI value), and in order to perform resolution from the network layer address to the ATM address (VPI), this ARP server The method is to make an inquiry.

The difference from the above (Method 2) is that the ARP is
If the receiving side terminal to which the (datagram transmission request ARP) is made belongs to an ATM-LAN different from that of the transmitting side terminal, that is, if the datagram cannot be delivered without crossing the network connecting device, the ARP is performed. As a response, the ATM address to (the CLSF processing unit of) the inter-network connection device is returned.

From this, the ARP server is ATM-L.
Table for each AN (network layer address and AT
M address (VPI value) correspondence table, see FIG. 27), and the ATM address of the inter-network connection device other than the network layer address of the node / IWU / terminal in the target ATM-LAN. It is written. In this way, the inter-network connection device (CLSF processing unit therein) is selected as the ARP response to the reception side terminal belonging to the ATM-LAN different from the transmission side terminal.

The setting of the table in this ARP server is as follows.
It may be done manually by hand. Alternatively, the table may be automatically set by the ARP server by a suitable routing protocol to obtain information about the routing.

The other points are almost the same as (method 2) in the case where the receiving side terminal is in the same ATM-LAN as the transmitting side terminal.

[0279] In the above (Method 2) and (Method II), when the ATM-LAN is a network that is not routed by the "VP routing method", for example, an ATM connection is established by a call processing server. In the case of a network, the ARP server that receives the ARP request is connected to a call processing server (not shown in the figure) between the sender terminal that issued the ARP request and the receiver terminal requested by the ARP request.
Setting and disconnection of ATM connection in ATM-LAN
An ATM connection (end-to-end inside the ATM-LAN, between the CLSF processing units inside the inter-network connection device outside the ATM-LAN) using ATM connection VPI / V
A method may be used in which the ATM cell header value such as the CI value is notified to the transmitting side terminal and further to the receiving side terminal if necessary.

Regarding the above (Method 2) and (Method II), the ARP server has a function of authentication (permission of connection setting etc.), that is, a function of performing address resolution only for a specific terminal. It may be.

[Method I] or (Method II) described above
As described above, the processing for the ARP request regarding the datagram transmission across a plurality of ATM-LANs is performed. (Address resolution protocol for datagram) If ARP fails in some way, the broadcast cell type is set to "broadcast" through the broadcast channel and the destination network layer address is written in the destination address field. As a result, the minimum communication can be performed within the ATM-LAN.

If the ARP fails, if the datagram to be sent is sent to the CLSF processing unit processing unit inside (or inside or outside) the inter-network connection device,
Since the processing unit recognizes the existence of all the network layer addresses of the nodes / IWUs / terminals connected to the inter-network connection device), the datagram is delivered to the CLSF processing unit to thereby transfer the data to the same ATM-LAN. It should be noted that gram delivery will also be possible.

Next, the rules for attaching an ATM cell header relating to datagram delivery in this embodiment will be described.

As the ATM cell in the ATM-LAN in this embodiment, UN in CCITT recommendation is used.
Since the I cell is used, a value of VPI from 0 to 255 and a value of VCI from 0 to 65535 can be used.

As described above, the rules for attaching VPI are as follows: each node / IWU / in the ATM-LAN.
At least one VPI value is assigned to each terminal, and an appropriate VPI value is sent from any sending terminal to the AT.
If the M-cell header is added and transmitted, it is routed to the corresponding receiving side terminal (receiving side terminal to which the VPI value is given) (VP routing method). In the present embodiment, the presence of a VPI value having a special meaning is considered (for example, for meta-signaling, network management, emergency, etc.), and ATM-LA is used.
VPI assigned to each node / IWU / terminal in N
The value is a value from 16 to 254. That is, the same AT
Node / IWU / that can exist in M-LAN
The total number of terminals is up to 239 in this embodiment. An exception to this VPI value allocation method is "VP
I = all 1 (255) ”, and in the case of this VPI value, an ATM cell having the VPI value is broadcast as a broadcast channel in the ATM-LAN.

It should be noted that the reserved VPI value (VCI
The value) may have the same meaning as the reserved VPI value (VCI value) in B-ISDN, which is being discussed in CCITT.

[0287] Next, an example of a rule for attaching VCI in this embodiment will be described. As explained earlier, "VC
"I = 0" is used for the response of the broadcast cell. Also, VPI
As in the case of, the reserved bits are set up to "VCI = 1 to 15". In the case of "VCI = 16-254", this shall be used for datagram delivery. That is, when an arbitrary sending terminal sends out a datagram, the destination address (destination VPI) is combined with "VC".
A cell having a value of “I = 16 to 254” is used. At that time, as the VCI value, the VPI assigned to itself
The value shall be entered. That is, “VPI value = # X”
When transmitting a datagram, the node / IWU / terminal to which is assigned is a VPI area of the header of the ATM cell, which is an ATM cell of the datagram, and the VPI value (data The resolution result of the gram transmission request ARP) is transmitted with the VPI value assigned to itself (that is, “VCI value = own VPI value”) entered in the same VCI area.

The node / IWU / terminal which receives this cell recognizes that the cell is delivered to itself according to the VPI value, and the VCI value is "16≤VCI value≤254".
Therefore, it can be recognized that this is a datagram. In order for the receiving side terminal to identify the source of transmission, unless a layer higher than the ATM layer such as AAL type 3/4 has an ID capable of identifying the source of transmission for each cell, the receiving side terminal may use different transmitting side terminals. , Or CLSF
Different ATM cell headers need to be added to the datagrams emitted from the processing unit or the like. This can be achieved by using the ATM cell header value assigning method as in this embodiment.

Furthermore, when the inter-network connecting device receives a cell whose VPI value is for itself and whose VCI value is 16 to 254, the cell is the inter-network connecting device itself or the inter-network connecting device. It can be recognized that the datagram is to be delivered across the cells, and the cell can be routed to the internal CLSF processing unit.

As described above, when the VCI value is 16 to 254, the receiving side terminal can recognize that the cell is a datagram, and the VCI value corresponding to each source terminal is added. Since the datagram is transferred after being transferred, the same source ATM-like AAL type 5 is used.
Datagram reassembly is also possible for AAL (ATM Adaptation Layer) in a mode in which packets from the SAP must be sent continuously (each sending terminal has a different VPI / VCI value). Therefore, it is necessary to note that it can be used. That is,
Datagram delivery can be performed without negotiation between the transmitting side terminal and the receiving side terminal regarding the VCI value to be used.

Regarding VCI value = 256 to 65535, it can be appropriately used by, for example, negotiating how to use it from end to end.

Next, the timing of making the datagram transmission request ARP will be described. The timing of making the datagram transmission request ARP does not necessarily have to be made when the datagram comes down from the OS (operating system) in the ATM board (ATM communication substrate). That is, when a datagram to be sent occurs, the datagram is made to wait on the ATM board or an arbitrary memory, a datagram sending request ARP is performed, address resolution is performed, and after the ATM address is determined. It is not always necessary to take out a datagram from the above-mentioned ATM board or arbitrary memory, convert this into an ATM cell, give a resolved ATM address and send out. This is because, while the ARP is being performed, the datagram is in a waiting state, which is a wasteful time from the standpoint of transmitting the datagram. It is considered that efficient datagram delivery can be achieved by performing address resolution in advance for a destination terminal that may send a datagram.

The datagram transmission request ARP is executed at the time of booting the node / IWU / terminal (the network layer address to which the datagram transmission request ARP should be transmitted is specified in the boot program, and the network layer address , A datagram transmission request ARP is performed by, for example, batch processing).

At the time of user login of the node / IWU / terminal (in the login program, that is, the program started at the time of login, the network layer address to which the datagram transmission request ARP is to be made is specified, and the network layer address is specified. With respect to the above, the datagram transmission request ARP is performed by, for example, batch processing.

For example, in the former method, any node /
The address of the ATM connection for the datagram with the other party (for example, NIS server, file server, network management server, network server, etc.) that is essential for the IWU / terminal is resolved. An application such as resolving the address of the ATM connection for datagrams with the other party who frequently performs datagram communication can be considered.

Here, the address resolution of the ATM connection at the time of booting or logging in as described above is not limited to the datagram, that is, the datagram delivery request ARP, but the connection setting request ARP.
Note that you can also go about.

Further, in the present embodiment, from the description that "ARP is performed at boot time or at login", the switch node setting (routing table setting for VP routing) is completed before ARP is performed. However, it is assumed that the terminal is ready to send a cell to a desired destination terminal by sending an ATM cell with an appropriate ATM address (VPI value). For example, when the terminal / IWU / node is booted, the switch node is first set, and then the ARP is performed.

However, setting of a switch node in advance (setting of a routing table for VP routing)
Note that there is a case in which the ATM connection has not been completed and "the ATM connection is set using a call setting server or the like at boot or login".

It should be noted that, as will be described later, when setting an ATM connection in advance at the time of booting or at the time of login, it does not particularly impose a communication resource. That is, the A stretched at the above stage
The TM connection is simply set in the table in the switch node A without performing connection admission control.
Since it is only a TM connection, it can be considered as a connection that is not subject to bandwidth management, that is, a connection with a low priority, and does not put pressure on communication resources.

The reason for this will be described below. In the present embodiment, an ATM connection within the ATM-LAN (in some cases, an A connection between ATM-LAN
ATM which includes bandwidth management (including TM connection)
There are connections and ATM connections that do not perform bandwidth management. The ATM connection that performs bandwidth management is a connection that can perform communications while maintaining a certain communication quality (QOS) (a cell discard rate above a certain level, a delay time below a certain level can be expected), and no bandwidth management is performed. The ATM connection is a connection with no guarantee of communication quality (there is no restriction regarding cell loss rate and delay time). An ATM connection that manages bandwidth is a connection with a high priority, and A that does not manage bandwidth.
The TM connection is considered to be a connection with a low priority, and for example, if there is no cell belonging to a connection with a high priority, priority control such as allowing passage of a cell belonging to a connection with a low priority is performed, and this Can be realized. Regarding the ATM connection that performs bandwidth management, setting is permitted only when the cell transmission path through which the connection passes and communication resources in the switching node are secured.
Since an ATM connection that does not perform bandwidth management is not subject to bandwidth management, it can be unconditionally accepted during call / connection acceptance control as long as the number of connections is less than or equal to the maximum reception limit of each connection management entity. The upper limit number of acceptances is defined by, for example, the capacity of the table in the switch node. Regarding the ATM connection for performing bandwidth management, a "bandwidth management server" is especially prepared (not shown),
This centrally manages the communication resources in the ATM-LAN and executes the calculation of the evaluation function at the time of admission control. Only the ATM connection permitted by this bandwidth management server can be used as an ATM connection for bandwidth management.

Next, FIG. 28 shows an embodiment of an ATM connection connection state between CLSF processing units in the inter-network connection device in the ATM backbone network. Here, for simplification, each physical wiring and the like are omitted. Further, other functions such as a call processing function and a header conversion function in the inter-network connection device, a switch node in the ATM-LAN, and a component in the ATM backbone network are omitted in the figure (actually, An ATM connection may be established from the switch node in the ATM-LAN to the CLSF processing unit in the inter-network connecting device).

As described above, in the ATM backbone network, the CLSF processing units in the inter-network connection device are connected by, for example, a permanent connection (VP or VC). This permanent connection is also a connection not subject to bandwidth management. For datagrams that traverse the ATM backbone network (or to terminals / nodes that reside within the ATM backbone network), these C
It is performed by the relaying of the LSF processing unit. That is, the CLSF processing unit in the inter-network connecting device terminates this once in the network layer or the CL layer, analyzes the destination address, and then (after making the ATM cell again if necessary), sends the destination. The ATM connection to be connected is appropriately selected and the datagram is delivered through the ATM connection. As shown in FIG. 28, CL in the inter-network connection device
Since the SF processing units are connected by a permanent ATM connection, the CLSF processing unit sends the datagram (which is made into ATM cells) to the C in the next inter-network connection device via these permanent ATM connections.
Relay to the LSF processing section.

Now, as described above, CL is set in the network connecting device.
By arranging the SF processing unit and performing the delivery of the datagram across the networks via the CLSF processing unit in the inter-network connecting device, the following advantages can be enjoyed.

(1) From the network connected to the inter-network connection device,
It is possible to directly access the CLSF processing unit. In addition, this access is A across multiple networks.
It can be performed without using the TM connection.

(2) ATM connected to the inter-network connection device
By performing processing here for datagram delivery across networks, the address system (V
The conversion of PI / VCI values) can be done intensively here.

(3) Routing information (network layer address, C) relating to the network connected to the inter-network connecting device
Information about L layer address, and the address and VP
Information related to the I / VCI value, etc.) is normally terminated and exchanged in the inter-network connecting device, so that the CLSF processing unit that analyzes and processes the datagram using the routing information is arranged in the inter-network connecting device. This is appropriate because the relationship between the routing protocol and the CLSF processing unit can be made close, and the routing table can be shared.

However, among the functions of the CLSF processing unit, after terminating the datagram (connectionless packet) and referring to the network layer address once, an appropriate ATM connection (VP connected to the terminal / node having the network layer address) / VC, or the function of sending to the VP / VC which is connected to the CLSF processing unit which is considered to have the function of delivering to the network layer address, requires a large device as a function in the network, and the CLSF processing is performed more than necessary. Providing the functions of some parts in the network is considered to lead to an increase in cost (over-spec). Therefore, a large-scale ATM as shown in FIG.
In the network, the CLSF processing unit is provided for each inter-network connection device or each ATM-LAN so that the amount of datagram communication between each ATM-LAN or with the ATM backbone network or an external network is sufficient. It is considered to be the final form when it becomes large.

Therefore, an example of the development of the arrangement method of the CLSF processing units in the large-scale ATM network will be described below. As described above, arranging the CLSF processing unit in each inter-network connecting device as shown in FIG. 28 is considered to be the final form of this development form. Below, the development of the method of arranging the CLSF processing unit will be explained in three phases.

FIG. 29 shows a diagram at the time of initial introduction as Phase 1. As described above, only one CLSF processing unit is provided in the ATM backbone network. The CLSF processing unit may be located in any of the network connecting devices or in any ATM-LAN.
It is assumed that the CLSF processing unit has a throughput that can sufficiently process the delivery of datagrams (cross networks) belonging to the large-scale ATM network in the phase 1 period. Here, as described above, ATM-
It should be noted that the datagram communication between the terminals in the LAN may be performed by an end-to-end ATM connection.

In this embodiment, the CLSF processing section does not exist in all the network connecting devices. However, in the inter-network connecting device, the termination processing unit of the routing protocol operating in the large-scale ATM network (hereinafter referred to as the routing processing unit. The inter-network connecting device in this phase 1 is the CLSF processing unit of FIG. It should be noted that there is a routing processing unit instead of the CLSF processing unit and the call processing unit of FIG. 2).

Normally, the inter-network connecting device is in a position to obtain the routing information regarding the network connected to the inter-network connecting device (or other network located further beyond the network directly connected to the inter-network connecting device). . From this, the routing protocol in the large-scale network may be operating in the form of exchanging the routing information between the network connecting devices. Even in this large-scale ATM network, the routing protocol as described above is working,
Each inter-network connection device collects or exchanges routing information. In this embodiment, the routing processing unit terminates the routing protocol.

Among these, the exchange of routing information or the exchange of location information (where the terminal having which address is located) (the operation of the routing protocol) is performed even if the datagram is delivered between the inter-network connecting devices. good.
ATM for exchanging routing information between network connecting devices
A connection may be provided, and if necessary, an ATM connection may be separately provided for each routing protocol to exchange routing / position information. In this way, the inter-network connecting device can obtain the information regarding the routing and the position.

In this phase 1, since the CLSF processing section does not exist in the inter-network connecting device, the address resolution method in the case where the receiving side terminal exists in the ATM-LAN different from the transmitting side terminal is first described. This is slightly different from the cases of (Method I) and (Method II) described above. One embodiment will be described below.

(Method I '): Direct ARP between the sender terminal and the routing function in the IWU Except that it is the routing function in the inter-network connection device that returns a response to the ARP request from the sender terminal. Basically, follow (Method I).

Since the routing processing unit in the inter-network connecting device has the routing information regarding the network to which the transmitting terminal belongs, it is determined whether or not the ARP request is closed to the ATM-LAN. be able to. Therefore, the AR
When the P request is not closed in the ATM-LAN, that is, when it is recognized that the address for address resolution does not exist in the ATM-LAN to which the sender terminal belongs, the routing function sends an ARP reply. To do. Here, as the ARP response, similarly to the case of the above (method I), the VPI value assigned to the inter-network connecting device is returned. Therefore, from the perspective of the sending terminal, CLS
The F processing unit is in the inter-network connection device (therefore, own ATM-LAN
It is not possible to judge whether or not it is located in (inside).

(Method II '): According to (Method II) when using the ARP server. However, the ARP server may be configured to receive information about routing from the routing processing unit in the network connection device.

However, the above (method I ') and (method I
In either case of I '), since the CLSF processing unit does not exist in the inter-network connecting device, the routing processing unit needs to transfer the sent datagram to the CLSF processing unit. Below, this one embodiment is shown.

This is a method performed by appropriately setting the header conversion function in the inter-network connecting device. That is, the datagram (actually
When M cells are sent (as described above, this can be determined by the arrival of the ATM cell having the VPI value assigned to the inter-network connection device and the VCI value of 8 to 254). ) Converts this into an appropriate header (described later) in the header conversion table, and does not terminate at the network layer or CL layer.
Only by the processing, the cell is transferred to the CLSF processing unit. The setting of the header conversion table (header conversion unit) may be performed when ARP is performed for the first time, or may be performed in advance.

In this case, the CLSF processing section needs to uniquely identify the transmitting side terminal for each received cell (the “identification” here means which terminal the transmitting side terminal is, for example. It does not mean to identify the network layer address etc., but it means to identify that the cells originate from different terminals (cells that belong to different connectionless packets).) Note that different ATM cell header values need to be added.

An example of an ATM cell header value allocation method by which the CLSF processing unit can uniquely identify the transmitting side terminal will be described below in the case where the "VP routing method" is applied to the ATM backbone network. I will explain.

Also in the ATM backbone network, "VP
Since the "routing method" is performed, at least one VPI value is also assigned to the CLSF processing unit in the ATM backbone network, and the datagram (combined into ATM cells) directed to the CLSF processing unit is , The V
A PI value is given (registered in the header conversion function). Therefore, the CLSF processing unit identifies the transmitting side terminal by the VCI value.

As the VCI value, for example, as shown in FIG. 30, the first eight digits of the VCI value are ATM-of the transmitting side terminal.
For the VPI value in the LAN and the subsequent 8 digits, the VPI value on the ATM backbone network side assigned to the inter-network connection device is used. By doing this,
The CLSF processing unit can uniquely identify the transmitting side terminal from the ATM cell header of the received cell (because different VCI values are always used if the transmitting side terminal is different). By registering such a VCI value in the header conversion function, the inter-network connecting device can transfer the datagram delivered over the inter-network connecting device to the CLSF processing unit only by the ATM layer processing. Becomes By taking such a method, 64k (=
The CLSF processing unit can support terminals up to 2 to the 16th power.

This rule can be applied not only to the two-layer network as in this embodiment but also to a multi-layer network by appropriately devising the VCI field hierarchy.

Here, in the ATM-LAN, there is a possibility that the datagram destined for the inter-network connection device itself will be transferred to the CLSF processing section according to the above-mentioned rule.
When a plurality of VPI values, for example, two #X and #Y, are given to the inter-network connecting device and the resolution of the address of the inter-network connecting device itself is obtained by ARP, “VPI value = # X”
, And when the address resolution of the receiving side terminal that crosses the network connecting device is obtained, "VPI value = #
"Y" is answered as an ARP response,
When "VPI value = # X", the datagram is taken into the inter-network connecting device, and when "VPI value = # Y", it is determined that the datagram is not addressed to the inter-network connecting device, and the header It is also possible to adopt a method of converting the header by the conversion function and then transferring the cell to the CLSF processing unit.

On the contrary, when the cell is received from the CLSF processing section, the reverse processing to the above processing is performed and the AT
It should be noted that the datagram may be sent to the terminal in the M-LAN.

A concrete example of the above exchange is shown in FIG.
Put together. Descriptions of switch nodes and the like are omitted. ATM-LAN 311 and ATM backbone network 3
12 is operated by the VP routing method, and ATM-
The terminals 31A, 31B, 31C in the LAN 311, and the inter-network connection device 31P have VPs #A, #B, #C, and #P, respectively.
An I value is assigned. ATM backbone network 31
The CLSF processing unit 31X in 2 and the inter-network connection device have #
VPI values of X and #Y are assigned.

[0327] The terminal within the ATM-LAN 311 transmits the datagram (A
(TM cells)) as shown in the figure.
Value = # P ”is added and transmitted. As mentioned above, VCI
As the value, the VPI value assigned to itself is put and transmitted (for example, in the terminal 31A, "VCI value = # A").

The header conversion table (the side from the ATM-LAN 311 to the ATM backbone network) in the inter-network connecting device 31C is set as shown in the figure, and the datagram (which is an ATM cell) is automatically set. Can be transferred to the CLSF processing section only by the ATM layer processing.

For example, the above datagram is CLSF
Since it goes to the processing unit, the VPI value is rewritten to #X,
Further, the VCI value is (1) The last 8 digits of the VCI value are
The CLSF processing unit that has received the cell-shaped data has a VPI value (= # Y in this case) of the internetwork connecting device in order to determine from which internetwork connecting device the datagram is transferred. ) Is entered. (2) The upper 8 digits of the VCI value contains the VPI value (= # A in this case) of the transmitting terminal in order to identify the transmitting terminal for each inter-network connecting device. It is operated as follows.

In this example, for cells arriving at the CLSF processing unit, VCI values other than 16 to 254 are entered even though they are datagrams.
Since only the datagram is basically transferred to the processing unit, this is appropriate as an ATM cell header value assignment rule for the CLSF processing unit (that is, in this example, the CLSF processing unit in the ATM backbone network uses ATM-L.
It means that the VCI value allocation rule is different from the VCI value allocation rule in AN). A datagram directed to the CLSF processing unit itself can be recognized as "a datagram addressed to itself when the first 8 digits of the VCI value is 0".

On the contrary, the datagram (which is converted into an ATM cell) from the CLSF processing unit to the inter-network connection device is
The VPI value is the VPI value of the inter-network connection device (in this case, = #
Y) is entered, and in the VCI value, the VPI value assigned to the CLSF processing unit (in this case, = # X) is entered in the lower 8 digits, and the VPI value of the receiving side terminal (receiving side terminal) is entered in the upper 8 digits. Is the terminal 31B, = # B) is entered.

Regarding the header conversion section (on the side from the ATM backbone network 312 to the ATM-LAN 311) in the inter-network connecting device, as shown in the figure, the ATM cell header value sent from the CLSF processing section, that is, below the VCI value. By referring to the 8 digit, it is recognized that this is a datagram sent from the CLSF processing unit, and the upper 8
V of the cell that refers to the digit and sends this value to the receiving terminal
Used as the PI value. Here, as described above, the VPI value assigned in the ATM-LAN 311 is entered as the VCI value of the cell transmitted to the receiving side terminal.

Also, the ATM backbone network 312 has 20
When no more than 0 network connecting devices (or ATM-LAN) do not belong, the lower 8 digit value of the VCI value is further hierarchized to 4 digits and 4 digits, for example, and the multistage configuration of the network connecting device is established. It is also possible to take.

Further, in this embodiment, the number of ATM-LANs connected to the inter-network connecting device is one. However, when the number of ATM-LANs connected to the inter-network connecting device is more than one, the ATM-LAN is more than one. Each ATM in the backbone network
-One VPI value may be assigned to each LAN.
In this case, the inter-network connecting device has a plurality of VPI values in the ATM backbone network. In addition, a plurality of inter-network connection devices (ATM-LA connected to the inter-network connection device
If a VPI value equal to the number of N) cannot be assigned, the datagram (in the form of ATM cells) is transferred to which terminal of which ATM-LAN between the CLSF processing section and the header conversion section of the inter-network connection device. It is necessary to negotiate a logical allocation method of VCI values, because it is necessary to decide whether to allocate.

Next, in FIG. 32, CLSF is set as Phase 2.
The figure when adding a processing part is shown. Thus, CLS
A plurality of F processing units are provided in the ATM backbone network. Some of the CLSF processing units may be located in any of the network connecting devices or in any ATM-LAN. In such a case, for example, the communication amount of datagrams in this network increases, and phase 1
It is considered that the throughput of the CLSF processing unit installed in 1 becomes insufficient and the CLSF processing unit is added.

Also in this embodiment, it should be noted that the routing processing unit exists in the inter-network connecting device. In this phase 2, the address resolution method when the receiving side terminal is in an ATM-LAN different from the transmitting side terminal is the same as in the case of phase 1. However, since the CLSF processing unit is added, the transfer destination of the datagram (which is made into an ATM cell) is added in the header conversion function in some inter-network connection devices.
In order to change to the SF processing unit, the header rewriting table is rewritten so as to be converted into the header (ATM cell header) of the ATM connection connected to the additional CLSF processing unit. It should be noted that the CLSF processing units can be added (or removed or changed in some cases) only by this rewriting, so that the CLSF processing units can be added or removed very easily.

In this case, it is necessary for the transmitting side terminal (receiving side terminal) in the ATM-LAN to completely recognize the change in the inter-network connecting device (the setting change of the header rewriting table, etc.) due to the addition of the CLSF processing section. Note that there is no such thing. The transmitting side terminal can perform communication using the address resolution and the datagram in exactly the same manner as in phase 1. This applies not only to Phase 2 but also to Phase 3 described later. By repeatedly performing the expansion (or switching or changing of the CLSF processing unit) as in this phase 2,
It is possible to change to a mode (Phase 3) in which the CLSF processing unit is arranged in all inter-network connecting devices such as No. 8. Here, when a CLSF processing unit is added in the inter-network connecting device, the CLSF processing unit may be added in place of the routing processing unit, or the CLSF processing unit may be installed with the routing processing unit arranged. It may be in the form of adding more parts. This is done only by changing the settings of the header conversion table (header conversion unit) and the add / drop processing unit (the switching function when the cells in the inter-network connection device are distributed by the ATM switch function). Therefore, it should be noted that the CLSF processing unit can be added and removed very easily.

Here, for the ATM connection between the inter-network connection device and the CLSF processing unit, and the ATM connection between the CLSF processing unit and each terminal, the AT is not subject to band management.
It should be noted that M connection is good.

Next, returning to FIG. 28, "Inter-CLSF processing unit A
The “RP” will be described. In FIG. 28, when the CLSF processing unit delivers a datagram, a permanent ATM connection (PVC, PV, or PV) to the CLSF processing unit in the inter-network connecting device set up in the ATM backbone network.
There is a case in which it is necessary to select which PVC / PVP should be sent out of P). That is, the destination address of the analyzed datagram (network layer address,
Alternatively, it may be a mail address or the like) is a table inside the CLSF processing unit (if this destination address, this P
If it is not registered in the table instructing to send to the VC / PVP), which PV from the destination address
The resolution of whether to send the datagram to the C / PVP is performed. This is "CL
This is referred to as "SF processing unit ARP". There are several methods as the method of performing this "CLSF processing unit ARP".

(Method 1): Method using ARP server This is a method similar to (Method 2) of ARP in datagram delivery in the ATM-LAN according to the first embodiment.
An ARP server is placed in the ATM backbone network (not shown). This ARP server has a table inside, and this table has a destination address and VPI / VCI.
And the values correspond. This VPI / VCI value is used as the CLSF processing unit (or AT in some cases) in another inter-network connection device.
CLSF processing unit in the M backbone network. This is in charge of the terminal device in the ATM backbone network)
It is the VCI / VPI value of VC / PVP. One embodiment of the outline of the table is shown in FIG. As described above, there are as many CLSF processing units as this table, and each table corresponds to an inquiry from one CLSF processing unit. Upon receiving the inquiry, the ARP server analyzes the VPI / VCI value corresponding to the destination address by referring to the table, and returns the analysis result (VPI / VCI value) to the CLSF processing unit of the inquiry source.

In the system in which the ATM backbone network assigns one VPI to the terminal / node inside the ATM backbone network and uses the VPI to route the cells in the ATM backbone network, the VPI to be assigned by the destination address.
Since the value is uniquely determined, it is not necessary to prepare a table for each destination address, and only one table needs to be prepared, so that the table amount can be significantly reduced. In this case, when sending a datagram or ARP, for example, the first 8 digits of the VCI value are all 0s (this is the mark for datagram delivery. That is, in the inter-network connection device, the VCI is
A cell whose upper 8 digits of the value is all 0 is transferred to the CLSF processing unit), and the lower 8 digits is filled with the VPI value of the inter-network connection device to which the transmission source CLSF processing unit belongs, and the received CLSF processing is performed. The unit can know the source of the cell and can continue the datagram delivery process. When the ARP is returned, if the VPI of the transmission source CLSF processing unit that was in the VCI area is used,
You can reply to RP without using broadcasting. If the CLSF processing unit does not need to know the transmission source CLSF processing unit,
The work of inserting the VPI of the inter-network connection device to which the transmission source CLSF processing unit belongs in the last 8 digits can be omitted.

Others are the same as the above-mentioned ATM- of the first embodiment.
This is almost the same as the method (method 2) described for ARP to the CLSF processing unit in the LAN.

(Method 2): Method of directly performing ARP between CLSF processing units in the ATM backbone network For other CLSF processing units in the inter-network connecting device or in the ATM backbone network in the ATM backbone network This is a method of directly performing ARP. That is, the CLSF processing unit on the side that performs ARP (that is, the side that asks for the VPI / VCI value) broadcasts the ARP request to the other CLSF processing units, or uses a method similar to broadcasting (for example, listening in order). This is a method in which the corresponding CLSF processing unit notifies the VPI / VCI value addressed to itself by answering this.

This is because one VPI is allocated to each node / inter-network connecting device in the ATM backbone network, and the VPI is used for routing in the backbone network using the VPI (VP routing system). This can be done by notifying the value and the appropriate VCI value.

Also, when the CLSF processing unit that has received this ARP determines that this is the destination address that it should be in charge of, the CLSF processing unit itself and the transmission source CLSF
VPI / VC of PVC / PVP tied between processing parts
This can also be done by notifying the I value, and the VP routing method is not necessarily required.

(Method 3): Method in which a table regarding all addresses is given to each CLSF processing unit in advance without using ARP If the network scale of the whole is not so large,
It is possible to give a table relating to all addresses to each CLSF processing unit in advance. The loading of this table may be performed, for example, when the CLSF processing unit is started up.

In this case, for a destination address that is not in the table, a transfer destination CLSF processing unit may be determined by default and transferred to this. This default transfer destination CLSF processing unit is a complete table. It is also possible to adopt a construction method such as having.

[0348] After such "CLSF processing part ARP", the datagram is VPI / VC which is the result of ARP.
Transfer to the CLSF processor indicated by I (relaying)
The destination address of the datagram delivered to the CLSF processing unit is analyzed again, and the datagram is relayed to an ATM connection connected to an appropriate destination. The set of the destination address and the VPI / VCI value resolved by the "Arp between CLSF processing units" may be stored in a table in the CLSF processing unit thereafter.

Regarding the ATM backbone network, sufficient consideration must be given to addressing in order to realize efficient routing. For example, in order to facilitate the creation of a subnet mask, physical addresses that are close to each other or LANs that connect to switch nodes in the same inter-network connection device / ATM backbone network are given network addresses with large overlapping values. Is.

Also in this system, it is possible to enjoy the advantages of the CLSF processing unit in the inter-network connecting device in the first and second embodiments.

Next, FIG. 34 shows the ATM connection connection state between the call processing unit in the inter-network connecting device and the terminals in the ATM-LAN, and the ATM connection between the call processing units in the inter-network connecting device in the ATM backbone network. 1 illustrates an embodiment of a connected state. Here, for simplification, each physical wiring is omitted. Also, other components such as a CLSF processing unit and a header conversion unit in the inter-network connecting device, a switch node in the ATM-LAN, and a component in the ATM backbone network are omitted in the drawing. In reality, the switch node in the ATM-LAN also sends A to the call processing unit in the inter-network connection device.
The TM connection may be established.

As described above, each terminal device in the ATM-LAN and the call processing unit in the network connecting device are connected by the ATM connection (VP or VC). This A
It should be noted that the ATM connection that connects the terminal device in the TM-LAN and the call processing unit in the inter-network connection device is not a connection that crosses the inter-network connection device as in the first and second embodiments. Is.

In the ATM backbone network, the call processing units in the inter-network connection device are connected by, for example, a permanent connection (VP or VC). It should be noted that this permanent connection is also an ATM connection closed in the ATM backbone network and not a connection that crosses the inter-network connection device.

By making the connection between the call processing units by the permanent ATM connection, it is possible to reduce the connection setting overhead which occurs each time the processing information is transferred between the call processing units, and between the three or more networks. The processing of the call / connection across the lines can be always performed by relaying between the call processing units in the inter-network connecting device via the permanent ATM connection. Further, it is possible to facilitate monitoring of traffic used for call / connection processing.

[0355] Below, from the terminal / node in the ATM-LAN (hereinafter referred to as the transmission side terminal) to another ATM-LAN.
AT to internal terminal / node (hereinafter referred to as receiving terminal)
A process for setting the M connection will be described.

If the terminal device / node in the ATM-LAN wants to establish an ATM connection across the inter-network connecting device and the ATM backbone network, the call processing unit in the inter-network connecting device should be used. become. Basically, it is similar to the first and second embodiments, but there are some differences, so a brief description will be given.

First, a description will be given of a case where only simple connection connection is required (bandwidth management is unnecessary).

First, the point that the terminal / node in the ATM-LAN (referred to as a transmission side terminal) that requests the setting of the ATM connection acts on the call processing unit in the inter-network connection device is the same as in the first and second embodiments. The process is almost the same.
Detailed description is omitted.

Next, the call processing unit in the inter-network connecting device that received this searches for which call processing unit in the inter-network connecting device the target address of the "connection setting request ARP" is in charge of. , Relays the ARP to a call processing unit in the inter-network connecting device. As shown in FIG. 34, the call processing units in the inter-network connection device are connected by the permanent ATM connection, so that the call processing unit sends the connection setting request next via these permanent ATM connections. Relaying is performed to the call processing unit in the inter-network connection device.

Here, it is sufficient to send to which PVC / PVP of the permanent ATM connections (PVC, PVP) of the call processing unit in the inter-network connecting device which is provided in the ATM backbone network. Sometimes you need to make that choice. That is, the analyzed destination address of the connection connection request (which may be a network layer address or a mail address) is a table inside the call processing unit (in the case of this destination address, this PVC / PV
If it is not registered in the table instructing whether to send to P or relay to this call processing unit), the resolution of which PVC / PVP from which the connection request should be sent from the destination address. Will be performed.
This is referred to herein as "call processing unit ARP".

There are the following several methods as the method of performing the "call processing part ARP".

(Method 1): Method of using ARP server The above is almost the same as the case of the ARP server in the CLSF processing unit of FIG. 28, except that the VPI / VCI value in the table inside the ARP server is different from that of the other network. The VCI of the PVC / PVP connected to the call processing unit in the inter-connection device (in some cases, the call processing unit in the ATM backbone network, which is in charge of the terminal device in the ATM backbone network).
/ VPI value. Note that this table can be easily shared with the table used in the CLSF processing unit.

(Method 2): Method of directly performing ARP between call processing units in the ATM backbone network For other call processing units in the inter-network connection device or in the ATM backbone network in the ATM backbone network This is a method of directly performing ARP. Since the method can be realized by almost the same method as (Method 2) in the CLSF processing unit shown in FIG. 28, details thereof will be omitted.

(Method 3): Method in which a table relating to all addresses is given to each call processing unit in advance without using ARP As in the case of the CLSF processing unit, if the entire network scale is not so large, all addresses are It is possible to give a table relating to each call processing unit in advance. The loading of this table may be performed, for example, when the call processing unit is started up. Moreover, the table is set to CLSF.
It can be easily shared with the processing unit. Details are CL
Since it is almost the same as the case of the SF processing unit, its description is omitted.

In this case, for a destination address that is not in the table, a transfer destination call processing unit may be determined by default and transferred to here. The default transfer destination call processing unit can also have a configuration method such as having all complete tables.

[0366] After such "call processing part ARP", the connection setting request is the VP which is the result of this ARP.
The connection setting request transferred (relayed) to the call processing unit indicated by the I / VCI and delivered to the call processing unit has the destination address analyzed again, and the receiving side terminal side of the first and second embodiments. The same operation as that of the call processing unit in charge of is performed. The set of the destination address and the VPI / VCI value resolved by the “inter-call processing unit ARP” is stored in a table in the call processing unit thereafter.

The above process is not limited to the connection setting request, and is almost the same for the connection setting / disconnection / change request.

Note that a permanent ATM connection is not established between the call processing units in the inter-network connecting device, and a permanent ATM connection / ATM connection is established between the call processing units each time a connection setting / disconnection / change request is made. It is also conceivable to use a stretch method or to exercise ARP over the entire ATM backbone network.

Further, when bandwidth management is performed for an ATM connection that crosses the inter-network connection device and the ATM backbone network, that is, when an appropriate QOS is required for the ATM connection, it follows the first and second embodiments. Is omitted.

Also in this system, it is possible to enjoy the advantages of the call processing unit in the inter-network connecting device in the first and second embodiments.

It should be noted that in the case of the call processing unit as well, as in the case of the CLSF, it is possible to increase / decrease / change the call processing unit in stages as shown in FIGS. 29, 32 and 28. is there. It is also the case that such a change can be dealt with by simply changing the table in the IWU. This is C
This is a general point not only for the LSF and the call processing unit but also for any server.

Next, FIG. 35 shows another embodiment of a method of arranging a call processing unit in a large scale network. In the example of FIG. 35, the call processing unit 351 is arranged in the ATM backbone network. The number of call processing units in this ATM backbone network does not necessarily have to be one, and may be distributed (may be load distribution or function distribution). When the call processing unit in the inter-network connecting device desires an ATM connection across the ATM backbone network, the connection processing request is relayed to the call processing unit 351. Here, as shown in FIG. 35, the call processing unit in the inter-network connecting device and the call processing unit 351 in the ATM backbone network are connected by a permanent ATM connection. It should be noted that this permanent ATM connection is not a connection that spans inter-network connection devices, but is a connection that is closed within the ATM backbone network. Call processor 3
Reference numeral 51 collectively sets, disconnects, and manages ATM connections in the ATM backbone network. This call processing unit sets / disconnects / changes ATM connections that cross the ATM backbone network between inter-network connecting devices. To do. The call processing unit in the inter-network connection device connects the ATM connection in the ATM-LAN and the ATM connection between the ATM backbone networks by appropriately setting the header conversion unit, and controls the ATM connection across the ATM backbone network. To do.

The same operation is performed in the terminal / inside the ATM-LAN.
It is also used when controlling an ATM connection between a node and a terminal / node in the ATM backbone network.

By arranging the call processing unit in this way, the call processing unit 351 in the ATM backbone network can be obtained.
ATM-connected to the ATM backbone network only within
Note that it is sufficient to retain the configuration information regarding the LAN. Here, the call processing unit in the inter-network connection device is
It can be said that it has a multiplexing function to the call processing unit 351 in the ATM backbone network.

Now, the ARP as described above
(From network layer address to ATM address = V
When performing address resolution to the PI value)
The entity that performs RP is the sending terminal (node / IWU / terminal)
There are several cases that can be considered in terms of where it is located. Each case will be described below. The term ATM board is used here,
This is an expansion board for communication of a terminal device that communicates using the ATM communication system, and is a board (board) having an ATM interface and a terminal internal bus interface.

First, the ARP request will be described.

(Case 1): ATM board autonomously ARs
When making a P request.

In this case, the datagram to be transferred is received from the host (eg OS) via the terminal internal bus interface. This datagram is a network layer datagram (eg IP datagram).
Therefore, the network layer address of the transfer destination is notified from the upper layer to the ATM board (stored in an appropriate area of the network layer datagram).

Incidentally, in parallel with this, information about a MAC address different from the ATM system may be transferred to the ATM board. This is an existing terminal (eg UNI
Instead of the X (registered trademark) TCP / IP + Ethernet) Ethernet board, an ATM board may be used as a communication board without any changes to the OS or device driver settings. is there. That is, considering the above example, the OS does not recognize that the communication board is an ATM board, but recognizes that it is an Ethernet board.

In this example, the function of the ARP request is A
The TM board has a network layer address and an ATM address (VPI in the case of the present embodiment).
Value, ATM cell header value including VPI / VCI value in the general case) and the correspondence table (ARP table) is A
It will be on the TM board. If the ATM address resolution has not been completed for the destination address of the datagram received from the upper layer, the ATM
The board will autonomously make ARP requests.

This ARP may be generated by the processor or the like mounted on the ATM board in terms of software / firmware, or may be generated by dedicated hardware on the ATM board. ARP generated
The request cell is sent to the ATM-LAN by the method as described above. While the ARP is being performed, the datagram is queued in the memory on the ATM board. During this time, the ATM board is next to the datagram,
The processing for the datagram sent from the upper layer may be performed, or the datagram may be converted into ATM cells.

When an ARP response is returned, the ATM address (VPI value) described in the response is used as an ATM cell header, an ATM cell header is generated according to the above rule, and the datagram (which is made into an ATM cell) is generated. A
It is sent to the TM-LAN.

At the same time, the address-resolved ATM address is transferred to the AR in the ATM board.
Register in the P table. By this registration, the next datagram destined to the same destination can be transferred from the network layer address to A without performing the address resolution.
Conversion to TM address can be performed.

The conversion from the network layer address to the ATM address may be performed by a processor or the like mounted on the ATM board as software / firmware, or dedicated hardware on the ATM board may be used. You can go.

The conversion table between the network layer address registered in the ARP table and the ATM address may be deregistered if it is not used for a certain period of time. This is a method that can be applied when determining the data to be deleted when the size of the ARP table is limited and there is data to be newly registered.

(Case 2): When the ARP request program is running as the OS program in the terminal or the device driver.

In this case, it is the program in the terminal that makes the ARP request. This ARP activation is as follows: (1) There is a correspondence table of network layer addresses and ATM addresses in the ATM board, and the ATM board side that needs the ARP request due to the appearance of the network layer address that does not exist in the correspondence table executes the ARP program. When booting (2) The OS or device driver has a correspondence table of network layer addresses and ATM addresses, and the appearance of a network layer address that does not exist in the correspondence table causes the OS or device driver to autonomously request the ARP request. Two cases can be considered in the case of recognizing and activating the ARP request processing program of the OS or the ARP request processing program of the device driver. Even in the case of (2), the correspondence table of the network layer address and the ATM address may exist in the ATM board.

The operation of the ARP processing program may be performed in several cases. (A) The ARP request processing program, or the ARP request cell or “the payload of the cell (that is, the content that the ARP request is transmitted) + The information that informs the ATM board that the information is ARP is autonomously generated and notified to the ATM board. The ATM board sends the above information as ARP to the ATM-LAN. That is, the ARP processing program has the ability to generate ARP information. (B) The ARP request processing program issues a command to the ATM board side to “perform an ARP request for the network layer address”. The ATM board side generates an ARP request cell and sends it to the ATM-LAN.

There are two possible cases.

[0390] Further, the AT when the ARP response is returned
There are some cases in which the M board can be supported. (I) There is a correspondence table of network layer addresses and ATM addresses in the ATM board on the ATM board, and the ATM address of the resolution result is registered in the correspondence table. . (Ii) There is a correspondence table of the network layer address and the ATM address on the OS or device driver side, and the ATM address of the resolution result is registered in the correspondence table. (Iii) There is a correspondence table of network layer addresses and ATM addresses in the ATM board both on the ATM board and on the OS or device driver side, and the ATM address of the resolution result is registered in both correspondence tables. There are three possible cases.

In (iii), the correspondence table on the ATM board may be a cache of the correspondence table of the OS or device driver. That is, only a part of the data in the correspondence table held by the OS or the device driver side is described. Various methods such as a FIFO method and a round robin method can be considered as a method of selecting how to describe a part.

Next, the ARP response will be described.

(Case A): ATM board autonomously ARs
When making a P response.

This is AR from the ATM interface side.
The ATM board that received the P request autonomously addressed A to itself.
Detects an RP request and sends an AR to the ARP request addressed to itself
This is the case of making a P response.

FIG. 36 shows an example of an ATM board which performs such processing. This ATM board includes an ATM interface 361, an ARP filter unit 362, an ARP processing unit 363, an inserting unit 364, a bus interface unit 365.
Consists of. The ATM interface 361 has a function of interfacing the ATM board and the ATM-LAN.

The ARP filter unit 362 extracts the ARP cell from the cells flowing on the input transmission path and outputs the ARP cell.
It has a function of dropping a cell in the ARP processing unit 363. Further, it may further have a function of inserting an empty cell in the empty cell slot after the drop.

The ARP processing section 363 analyzes the ARP cell sent from the ARP filter section 362, and
Check whether the cell is an ARP cell destined for itself by analyzing the destination address, discard the cell if it is not an ARP cell destined for itself, and generate an ARP response cell if it is an ARP cell destined for itself. , The ARP response cell is inserted into the insertion unit 3
It has a function of sending to 64. The processing of the ARP processing unit may be performed by hardware logic, or may be performed by a processor or the like in software / firmware.

The inserting unit 364 appropriately multiplexes the ARP response cell sent from the ARP processing unit 363 and the cell sent from the bus interface unit 365, and
The TM-LAN side has a function of transmitting the cell.

The bus interface section 365 has a function of interfacing the ATM board with the bus inside the terminal.

Here, in FIG. 36, only typical ATM cell transfer paths are indicated by arrows. In reality, the upper CPU and the like access each other via the internal bus of the terminal, for example, notify the ARP processing unit of the network layer address of the terminal device, exchange error notifications, etc. There is a control line for realizing the function of.

The ARP request cell arriving at this ATM board is sent to the ARP processing unit 363 by the ARP filter unit 362.
If the ARP cell is dropped to the side and is addressed to itself (for the terminal on which the ATM board is mounted), the ARP processing unit 363 generates an ARP response cell and the insertion unit 3
It is sent to the ATM-LAN side via 64. that time,
Network layer address and AT in ATM board
When the correspondence table with the M address exists, the information (specifically, the sender address) included in the ARP request cell is used, and the information included in the sender address in the correspondence table (the network of the sender terminal is used). (Corresponding information of layer address and ATM address) may be registered.

If there is a correspondence table between the network layer address and the ATM address in the OS or device driver, the above information (correspondence information between the network layer address of the transmission source terminal and the ATM address)
The information may be notified to the OS or the device driver side in order to register the information.

As can be seen from the above description, both the ARP request and the response are made by the ATM board or software (that is, by the OS or the device driver).
In addition to the form such as “performing an ARP request, software (that is, the OS or device driver
It should be noted that a form in which the ATM board performs the ARP response "is also possible.

(Case B): When the OS program or device driver in the terminal makes an ARP response.

In this case, it is the program in the terminal that makes the ARP response. This ARP response program is started when (1) the ATM board recognizes the arrival of the ARP request cell addressed to itself and notifies the OS or the device driver side. (2) The ATM board transfers the ARP request cell and other cells to the OS or the device driver side without distinction, and the OS or the device driver transmits the ARP addressed to itself.
When the arrival of the request cell is recognized and the ARP response processing program of the OS or the ARP response processing device driver is started. There are two possibilities.

There are some cases in which the operation of the ARP response processing program is possible. (A) The ARP response processing program uses the ARP response cell or "the payload of the cell (that is, the content of the ARP response)."
+ Information that informs the ATM board that the information is an ARP response "is autonomously generated and notified to the ATM board.
The ATM board uses the above information as the ARP response cell
It is sent to the TM-LAN. That is, the ARP processing program side has the ability to generate ARP response information. (B) The ARP response processing program displays “ARP for the network layer address (and ATM address)
Send a command to the ATM board side. ATM
The board side generates an ARP response cell, and the ATM-LAN
There are two possible cases: sending the data to the user.

In the third embodiment, the AT
Although the "VP routing method" is used as an example of the cell routing and addressing method in the M-LAN or ATM backbone network, the various methods of the present invention are not limited to the VP routing method. Note that it can be applied to general ATM communication methods.

For example, instead of the "VP routing method", "a processing unit such as a call processing server sets an end-to-end ATM connection every time a connection connection request is made (the ATM cell header is rewritten during cell transfer). May be used), a method of performing end-to-end communication (in the following,
(Also called a call processing server system) ATM-LAN or ATM backbone network "or" ATM-LAN is VP
A large-scale ATM network operated by a routing system and an ATM backbone network operated by a call processing server system, and conversely, an "ATM backbone network operated by a VP routing system and an ATM-LAN operated by a call processing server system. The present invention is also applicable to an ATM network in which various types of systems are mixed, such as a large-scale ATM network ", a VP routing system for some ATM-LANs, and a call processing server system for some ATM-LANs. The various methods in can be easily applied.

In this embodiment, the ATM-L
The datagram delivery method in the AN or ATM backbone network has been described.
-It should be noted that the present invention is not limited to a LAN or an ATM backbone network, and can be easily applied to a subnetted ATM-LAN or a subnetted ATM backbone network.

Further, the inter-network connection devices in the first, second and third embodiments described so far are arbitrary ATM-
It can be considered to belong to the LAN or the ATM backbone network. Further, it is possible to consider that the inter-network connection device belongs to all the connected networks.

The network connection device in the above-described embodiments is a computer (workstation or the like).
In addition, it may have a form in which an expansion unit / expansion board is added, or may have a structure integrated with a computer. In this case, the CLSF processing unit, the call processing unit, and the IWU management unit may be realized by the CPU of the computer.

(Fourth Embodiment) Next, an embodiment relating to datagram communication within the subnetwork will be described. Here, as described in the case of a general ATM network, Ezaki, Tsuda, and Natsuhori: "Methods for realizing data transfer in ATM-LAN", The Institute of Electronics, Information and Communication Engineers (Information Network Research Group materials, March, 1993). Na V
The case where the PI routing method is applied will be described respectively.

(Embodiment 4-1) A case where datagram communication inside a sub-network is applied to a general ATM network.

FIG. 40 shows an embodiment of the terminal (T (T
E) When a datagram transmission request is issued to the terminal 411, the terminal 411 uses the ATM connection 41A and uses the address resolution server (hereinafter referred to as ARS) 413.
, To transfer the datagram to the target terminal
A TM address acquisition request (AR request) is made. This address acquisition request is always performed when a datagram transfer request is generated, or is performed only when the address information of the destination terminal is not in the address resolution table stored in the terminal 411 (see FIG. 42). is there. In the latter method, if the address already exists in the AR table, it is not necessary to execute the AR request and AR response procedures.

The ARS 413 uses the VCI / VPI information (VC to be added by the terminal 411) which is the ATM connection identifier for transferring the datagram to the destination terminal 412.
I / VPI information) is notified to the terminal 411 using the ATM connection 41B (referred to as AR response). Upon receiving the AR response, the terminal 411 adds the notified VCI / VPI and inputs the datagram to the network. The datagram is sent to the terminal 4 through the ATM connection 41C.
Delivered directly to 12. In the case of this embodiment, the ATM connection needs to be set in a full mesh state between all the terminals in the sub-network.

FIG. 42 shows the transmitting terminal (terminal 4 in this example).
11 is a flowchart showing an example of a protocol executed in 11). This is an example of the case where the transmission side terminal can cache the address information of the transmission destination. In step 432, the cache table for address resolution in the own terminal is searched. If there is no information of the destination terminal 412 in the cache entry, the AR response is A
Perform on RS413.

FIG. 41 shows terminals 411, 412 and AR.
The data exchange between S413 is shown. this is,
This is an example of the case where the address resolution cache entry of the terminal 411 does not include the information of the destination terminal 412. The AR request 41A and the AR response 41B can be realized by a point-to-point ATM connection, but can also be realized by using a broadcast channel.

FIG. 43 shows another embodiment. Causes CLSF 414 to perform the actual datagram transfer. When a datagram transfer request is generated at the terminal 411, the terminal 41
1 carries out the resolution of the ATM connection information for transferring the datagram to the target terminal 412. When the terminal 411 does not have ATM connection information for transferring the datagram to the destination terminal 412, that is, when there is no entry in the cache table, the ATM
Address resolution is performed using the connection 41A (AR request).

When the destination terminal is the terminal within the own sub-network, the ARS 413 determines that the terminal 411 has the CLSF.
The ATM layer address information for transferring the datagram to 414 is returned to the terminal 411 (AR response). The embodiment in the case where the terminal to which the datagram is to be transferred belongs to a network other than its own sub-network is
This is explained in the following subsections.

The terminal 411, which has completed the address resolution, adds appropriate VCI / VPI (VCI / VPI information acquired in the cache table or AR response) to the cell for transferring the datagram, and adds it to the network. throw into. This VCI / VPI is an identifier of the ATM connection 441, and the cell is transferred on the ATM connection 441 and reaches the CLSF 414. C
The LSF 414 analyzes the address information of the received datagram, adds VCI / VPI for transferring the datagram to the destination terminal 412, and puts the cell into the network. The input cell is ATM connection 442.
To reach the terminal 412. In the case of this embodiment, it is necessary to set a star-shaped ATM connection between the CSLF 414 and each terminal. It should be noted that the AR request and the AR response can be performed using the broadcast channel instead of the point-to-point ATM connection.

The address resolution procedure performed by the ARS 413 may be performed by searching for the address space information (address mask) of the network. As shown below, the ARS 413 may analyze which network address space the terminal exists even for an external network.
It is not necessary to resolve the VCI / VPI information for accessing the connection.

FIG. 44 shows the procedure of data transfer. Here, regarding the transfer of the datagram from the terminal 411 to the CLSF 414, once the entire datagram is once captured by the CLSF 414, the datagram is collectively collected.
Although the case of transferring to 12 is shown, it is also possible to transfer the datagram in a pipeline.

(Embodiment 4-2) A case where VPI routing is applied to datagram communication within a subnetwork.

As shown in FIG. 45, it is assumed that a VPI is assigned to each network element. Each terminal /
The server is equivalent to having a multipoint-point ATM connection established from all UNI points in the subnetwork. That is, the terminal is V of the destination terminal.
When a cell with PI is added to the network, the cell is transferred to the target UNI point. For example, ARS4
In order to transfer the cell to 13, the VPI ₄₁₃ may be added as the VPI.

The method described with reference to FIG.
6A, 46B and 46C are used. Terminal 411 is VPI
_The AR request cell having ₄₁₃ as VPI information is transferred to the ARS ₄₁₃ . At this time, the ARS 413 can recognize that the received cell is the cell transmitted from the terminal 411 by using the VCI information or the identifier of the upper layer. For example, if VPI _411, which is the VPI information of the terminal 411, is written in the VCI field, the ARS 413 will be an ATM.
The cell received by referring to the header is the terminal 411.
You can recognize that it is from. Further, the VCI information may be an identification number that explicitly indicates that the cell is an AR request cell for datagram communication.

The ARS 413 which has performed the address resolution of the terminal 412 has VPI = VPI in the AR response cell.
_{Write 411} and input to the network to the terminal 411. Similar to the ARS 413, the terminal 411 recognizes that the received cell is an AR response using at least one of the VCI information and the upper layer header information. At least VPI _412, which is the access address information of the terminal 412, is written in the AR response cell.

The identification information for identifying that the cell for datagram transfer received by the terminal 412 is one transferred from the terminal 411 is VCI information or header information of the upper layer. ARS413
Can also be notified to the terminal 411 as the information written in the AR response. The simplest method of identifying the source and the cell type at the receiving source is to perform the above-mentioned series of procedures, and as the VCI field information, 8 bits are the source VPI information, and the last 8 bits are the cell type. A method of indicating is possible.

Terminal 411 V of cell to be transferred to terminal 412
The following methods are available for coding the CI field (16 bits).

Example 1: 8 bits are the access address of the terminal itself (the same number as the VPI number), and the remaining 8 bits are identification numbers indicating connectionless communication. Example 2: 8 bits are the access address of the terminal itself. The remaining 8 bits are the identification number of your network. However, at this time, each terminal needs to acquire the VPI for connectionless communication separately from the connection-oriented VPI (CL and CO use different VPIs).

Example 3: 16 bits are set when the terminal boots. It is also possible for the receiving side terminal to assign appropriately.

The method described with reference to FIG.
6A, 46B, 46D and 46E are used. Terminal 411
AR requests the AR request cell using VPI ₄₁₃ as VPI information.
Transfer to S413. The ARS 413 that has performed the address resolution of the terminal 412 uses the VPI as the AR response cell.
= Write VPI ₄₁₄ and populate the cell (AR response) into the network. In the AR response cell, CLSF4
At least VPI _414, which is 14 access address information, is written. The information for identifying that the cell for datagram transfer received by the CLSF 414 has been transferred from the terminal 411 is VCI information or header information of the upper layer.
It is also possible to notify the terminal 411 as the information written by the RS 413 in the AR response. The CLS 414 parses the received cell address information and VPI = VPI ₄₁₂ to transfer the datagram cell to the terminal _412.
Is added to the cell and the cell is put into the network. The cell is transferred to the terminal 412 via the ATM connection 46E.

Five specific examples of this embodiment are shown below.

(1) The CLSF 414 performs resolution of the access address of the receiving terminal. The CLSF 414 analyzes the address of the destination terminal based on the network layer address written in the received datagram (or the address of another layer is also possible). At this time, the datagram is once reassembled by the CLSF 414.

(2) The CLSF 414 performs resolution of the access address of the receiving terminal. The CLSF 414 analyzes the address of the destination terminal based on the network layer address written in the received datagram (or the address of another layer is also possible). At this time, the datagram is not once reassembled by the CLSF 414, and the cell is relayed by the pipeline process. That is, the address information written in the head cell of the datagram is analyzed to analyze the access address of the destination terminal, and the cells after the head cell are rewritten to VPI / VCI based on the VCI information and sent to the destination terminal. Relay. The CLSF 414 needs to assign a different VCI for each datagram.

(3) The transmitting terminal resolves the access address of the destination terminal and writes it in the payload part of the head cell. The CLSF 414 that has received the head cell reads the information in the payload section of the head cell and uses this to transfer the cell to the destination terminal. At this time, the datagram is once reassembled by the CLSF 414.

(4) The transmitting terminal resolves the access address of the destination terminal and writes it in the payload part of the head cell. The CLSF 414 that has received the head cell reads the information in the payload section of the head cell and uses this to transfer the cell to the destination terminal. At this time, the datagram is not once reassembled by the CLSF 414, and the cell is relayed by the pipeline process. In other words, the access address of the destination terminal is analyzed by analyzing the address information written in the first cell of the datagram,
The cells after the first cell are VPI / VPI based on the VCI information.
The VCI is rewritten and relayed to the destination terminal. CL
The SF 414 needs to assign a different VCI for each datagram.

(5) The transmitting terminal resolves the access address of the destination terminal and transfers it to the CLSF 414 using the VCI field. That is, for example, VC
The 8 bits of I are the access address of the destination terminal, and the remaining 8 bits are the access address of the source terminal. CLSF
414 copies the address of the destination terminal in the VCI field and relays the cell to the destination terminal. Relaying includes a method of once reassembling a datagram and a method of relaying cells in a pipeline.

(Fifth Embodiment) Next, as an embodiment relating to datagram transfer to an external network, a case of using a two-layer network will be described first.

(Embodiment 5-1) In case of using general ATM network-No. 1

FIG. 46 shows a schematic diagram of the network architecture of this embodiment. This network has 2
It consists of a hierarchical network. The networks 471 to 475 are internetworked via IWUs (Internetworking Units) 476 to 479. Network 471 and public network 475
Are connected via IWU479. IWU47
6 to 479 can realize relaying of ATM cells without terminating the ATM connection. That is, it has a function of converting the VCI / VPI of the received cell into the VCI / VPI assigned to the corresponding ATM connection in the adjacent network.

47 and 51 show the setting of the ATM connection associated with the address resolution.
Each ARS 481 to 484 manages address information of at least a terminal or a network accommodated in the networks 471 to 474 to which each ARS belongs. Figure 4
8, network 472 to other network 47
ATM connections 496, 497, 49 needed to transfer datagrams to 1, 473, 474, 475
The setting of 8,49B is shown. IWU476 to CLSF4
An ATM connection (one-way ATM connection) to 91, 493, 494 is set. Also, an ATM connection 49 to the CLSF in the public network 475
B (two-way ATM connection is usually defined) is set. A similar connection is set for other sub-networks. The location where CLSF and ARS are located can also be located at the IWU location. It is also possible that CLSF and ARS are present at the same position.

The cell (connectionless communication cell) to be transferred from the public network 475 to the terminal existing in the network discussed here is once the network 471.
Connectionless communication (ATM
There is a server that terminates the connection. Public network 4
From the viewpoint of 75, for connectionless communication, this server is defined as an access point. This server terminates the ATM connection and transfers the datagram to the destination terminal. The datagram transfer method from the server is realized in the same manner as the datagram transfer from each terminal to another terminal.

The protocol of the terminal in this embodiment, that is, the procedure for the terminal to send the connectionless communication datagram to the target terminal is as follows.

(1) The terminal issues an address resolution request (AR request). This is always done if the terminal is not able to resolve the address on its own, for example when there is no entry in the address resolution cache table.

(2) The terminal acquires VCI / VPI information, which is the identifier of the ATM connection prepared for accessing the corresponding terminal, from the address resolution server.

(3) The terminal attaches the acquired VCI / VPI and inserts a cell into the network to complete the transfer of the datagram.

The terminal does not need to perform the connection setting procedure defined in the ATM network when transferring the datagram.

There are two types of protocols for the address resolution server in this embodiment: "backbone ARS initiative" and "front end ARS manual".
Each is as follows.

(I) Backbone ARS initiative ARS482 existing in each network 472-474
~ 484 and ARS481 present in network 471
A star-shaped ATM connection (two-way communication channel) is formed between and. For example, the terminal 47A is the terminal 47
In order to acquire the VCI / VPI for transferring the datagram to D, the terminal 47A transfers an address resolution request cell having the address information of the terminal 47D to the ARS482 which is the ARS of its own network 472. Upon receiving the request cell, the ARS482 analyzes that the address of the target terminal written in the received cell is not the own network 472, and the network 4
AT already set to ARS481 existing in 71
The M connection 485 is used to relay the address resolution request cell. Alternatively, A
It is also possible to cache the network address information of the external network already acquired in the past by the RS 482 through the ATM connection 485 and the VCI / VPI information for transferring the cell to each corresponding CLSF.

The ARS 481 uses the address information of the destination terminal 47D possessed by the received cell to transfer the datagram to the CLSF (existing in the network 474) to which the datagram should be transferred.
The I information (VCI / VPI information will be described later) is analyzed, and the VCI / VPI information is transferred to the ARS482. The ARS482 which received the VCI / VPI information,
V to be used by the terminal 47A based on the VCI / VPI information
It returns CI / VPI information (AR response).

The address resolution in the ARS 481 is performed as follows. The ARS 481 has address information (address space information) of the terminal accommodated in the own network 471 and address space information of the sub-networks 472 to 474. The ARS 481 compares the address written in the received address resolution request cell with the address space information of each sub-network to analyze the corresponding transfer destination network. Here, it should be noted that the ARS does not necessarily have to analyze the host address of the destination address, but may analyze the network address when performing the comparison.

There are the following two methods for identifying the datagram for the public network 475.

(A) It indicates whether the address information written in the address resolution cell is explicitly a datagram intended for the public network 475 or a datagram not intended for the public network. In other words, when the terminal knows whether it is for the public network or not when requesting the address resolution, the terminal can explicitly identify whether the ARS is for the public or not. Transfer the session cell to the ARS. When the address information is not the address for the public network 475, the ARS
If the address does not exist in the 481 address entry, the information that the address does not exist is ARS.
Sent to 482.

(B) When the address held by the received address resolution request cell does not exist in the address entry of the ARS 481, the address is public network 4
It is determined to belong to 75.

As described above, the ARS 481 includes terminals and sub-networks 47 belonging to the network 471.
Addresses of 2,473,474 and information of address space are held, and resolution of addresses is performed.

FIG. 49 and FIG. 50 show views of the sub-network space in this embodiment from the standpoint of ARS. FIG. 49 is an address space view of the adjacent network viewed from the ARS 481. Further, FIG. 50 is an address space view of the adjacent network viewed from the ARS 482. From the ARS 482, the network 511 connected by the IWU 476 is initially invisible as a plurality of subnetworks. From ARS482, AR
Only after exchanging information with S481, the address space of each sub-network is resolved.

The address information (ATM layer address information) received by the ARS 482 from the ARS 481 is IWU.
A from 476 to CLSF in the desired subnet
This is information of a TM connection identifier (VCI / VPI information, which may include upper layer identification information in some cases). For example, from terminal 47A to terminal 47D
When the datagram is transferred to the terminal 47F, the identifiers of the ATM connections 495 and 497 for accessing the CLSF 494 are notified (AR response), and when the datagram is transferred to the terminal 47F, the ATM connections 495 and 496 for accessing the CLSF 491 are transmitted. Notify the identifier of. Note that the ARS482 detects that the ATM connection is IW based on the VCI / VPI information received from the ARS481.
VCI / V as normally relayed by U476
The PI information is notified to the terminal 47A. The VCI / VPI number notified to the terminal 47A is rewritten by the IWU 476 into another VCI / VPI.

(Ii) Front-end ARS initiative ARS482 existing in each network 472-474
~ 484 and ARS481 present in network 471
47 and the star-shaped ATM connection shown in FIG. 51 or the mesh-shaped ATM connection shown in FIG. Each ARS acquires the address space information and ATM connection information (VCI / VPI) of the external sub-network when viewed from its own sub-network by using the ATM connection defined in FIG. 47 or 51. It can be said that FIG. 47 shows a form in which the ARS 481 is a master ARS, and FIG. 51 is a distributed form in which each ARS operates independently. When the network does not have three or more layers, it is more appropriate to use the backbone network as the master as shown in FIG.

On the other hand, when there is no limitation on the hierarchy of the network, which of the forms shown in FIGS. 47 and 51 is selected depends on the form of the network or the form of management and the number of sub-networks existing in the network. . For example, the terminal 47A may acquire the VCI / VPI to transfer the datagram to the terminal 47D.
A is ARS4, which is the ARS of his network 472
The address resolution request cell having the address information of the terminal 47D is transferred to 82. Upon receiving the request cell, the ARS 482 analyzes that the address of the target terminal written in the received cell is the network 474, and the datagram is transferred to the CLSF (which exists in the network 474) to which the datagram is to be transferred. Of the VCI / VPI information (VCI / VPI information will be described later) for transferring the information (AR response) to the terminal 47A.

The address resolution in the ARS482 is performed as follows. The ARS 482 is the address information (address space information) of the terminal accommodated in the own network 472 and the sub-networks 471, 47.
It has information on the address space of 3,474. ARS
482 compares the address written in the received address resolution request cell with the address space information of each sub-network, and analyzes the corresponding transfer destination network. Here, it should be noted that the ARS does not necessarily have to analyze the host address of the destination address, but may analyze the network address when performing the comparison.

There are the following two methods for identifying the datagram for the public network 475.

(A) It indicates whether the address information written in the address resolution cell is a datagram for the public network 475 or not for the public network. In other words, when the terminal knows whether it is for the public network or not when requesting the address resolution, the terminal can explicitly identify whether the ARS is for the public or not. Transfer the session cell to the ARS. When the address information is not the address for the public network 475, the ARS4
If the address does not exist in the address entry 82, it is determined that the address does not exist.

(B) When the address held by the received address resolution request cell does not exist in the address entry of ARS482, the address is public network 4
It is determined to belong to 75.

As described above, the ARS 482 is the terminal and sub-network 47 belonging to the network 472.
It has the information of the addresses 1, 473 and 474 and the address space, and performs the address resolution.

52 and 53 are views showing the view of the sub-network space in this embodiment from the viewpoint of ARS. FIG. 52 is an address space view of the adjacent network seen from the ARS 482, and FIG. 53 is an AR.
It is an address space view of the adjacent network seen from S481. From each ARS, the address space of all sub-networks is resolved.

When the address information (ATM layer) received by the ARS 482 from other ARS is the identifier (VCI / VPI information) of the ATM connection from the IWU 476 to the CLSF existing in the target subnet, including the identification information of the upper layer. There is information). For example,
When transferring the datagram from the terminal 47A to the terminal 47D, the identifiers of the ATM connections 495 and 497 for accessing the CLSF 494 are notified (AR response), and when transferring the datagram to the terminal 47F, C is sent.
The identifiers of ATM connections 495 and 496 for accessing the LSF 491 are notified. In addition, ARS48
2 notifies the terminal 47A of VCI / VPI information such that the ATM connection is normally relayed by the IWU 476 from the VCI / VPI information received from another ARS. The VCI / VPI number notified to the terminal 47A is rewritten by the IWU 476 into another VCI / VPI.

Between ARSs, not only a protocol for exchanging address space information of each sub-network but also a routing protocol for datagram communication (connectionless communication) between sub-networks operates. Specifically, A between IWU and CLSF as shown in FIG.
Manages TM connection settings. In addition, individual AT
The M connection is separated by IWU (closed inside the sub-network), and another ATM connection server process and routing server process
It controls M connection routes and ATM connection management (for example, VCI / VPI management).
The S exchanges control messages with these servers and IWUs, and manages ATM connections required for connectionless communication.

FIG. 54 shows the VCI that the IWU 476 should have.
An example of the rewriting table of / VPI is shown. It should be noted that VCs added to transfer cells to the same CLSF in the figure
The I / VPI does not necessarily have to be a different number. That is, not only the VCI / VPI information but also the identifier information in the upper layer data unit can be combined to identify which datagram the cell received by the destination CLSF belongs to. Similarly, the VCI / VPI added to the cells transferred from the same terminal do not necessarily have to be different numbers.

Further, due to congestion or failure in the sub-network, it may be necessary to use an ATM connection having a route different from the ATM connection used in the normal state. In this case, a routing control process that manages and controls the VCI / VPI and routing table information set in the table of each switch.
(The control process that manages the address may be another process), so that the VCI / VPI number shown at the UNI point (user interface point) can be kept the same even when the route in the subnetwork changes. Management control.

Next, when the access points of various servers (for example, CLSF) move, the connection identification number (VCI /
It is sufficient to reboot so that the VPI) becomes the same. Also, at the time of rebooting, a request message for discarding information for old access from the cache table (new access information if necessary) is transferred to the related access point. In the latter case, in IWU, FIG.
You need to change the entry information in the table as shown in 4 (using the information in the forwarded message,
Or execute a protocol to obtain new information).

Next, the routing to the destination terminal in this embodiment will be described. The final datagram is delivered to each terminal only for the network to which each CLSF belongs (see FIG. 48). That is, for example, CL
The SF 491 delivers the datagram to the terminals belonging to the network 471 (the networks 472, 473, 474 and 475 do not serve). Similarly, CL
The SF494 delivers the datagram only to the terminals in the network 494. If the network address of the datagram received by each CLSF does not exist in the address entry of that CLSF, or if the address of the received datagram is not an element of the network address space of that network, the datagram is incorrect. It is determined that the product has been delivered. The actions for delivery of erroneous datagrams are not discussed here. That is, each CLSF need only have the address information of the terminal of the network to which it belongs. When the address of the received datagram exists in the own network, an appropriate ATM connection is selected and the datagram is relayed.

FIG. 55 shows an example of protocol processing when a datagram is transferred from the terminal 47A to the terminal 47D. The ATM connection is once terminated with CLSF494. That is, OSI layer 3 in CLSF494
Is terminated. Layer 3 with CLSF494
And the data unit is transferred to the terminal 47D using the ATM connection. Thus, when transferring a datagram to a terminal other than its own sub-network, datagram delivery is realized end-to-end with only one ATM connection termination.

(Embodiment 5-1-1) Next, a more specific embodiment will be described.

56 and 57, the terminal 47A
An embodiment in which a datagram is transferred from the terminal 47D to the terminal 47D will be briefly described. FIG. 56 shows FIG. 50 and FIG. 49.
57 is an embodiment based on the management view shown in FIG.
Is an embodiment based on the management view shown in FIGS. 52 and 53.

Address resolution in this embodiment is performed as follows.

When the terminal 47A does not have the ATM layer address information for transferring the datagram to the terminal 47D when transferring the datagram to the terminal 47D, it has the address information of the terminal 47D to the ARS482. The address resolution request cell is transferred using the ATM connections 571 and 581. However, the ATM connections 571 and 581 can be realized by a point-to-point connection or a broadcast connection. Upon receiving the address resolution request cell, the ARS 482 receives the address resolution request cell via the ATM connection 572, and thus the ARS 482 receives the address resolution request cell via the ATM connection 572 because the address to be analyzed by the address resolution request cell is not the own network 472.
81. The following method can be considered as a procedure for the ARS 482 to receive the address resolution request cell and transfer the request cell to the ARS 481.

(1) When the ARS takes charge of all responses to the address resolution request cells generated in the network, the ARS first screens the address resolution request cells. That is, it verifies whether the address in the received cell is an element of the address space of the own network by using a network mask or the like. If the address is within the own network, the address table is searched and the ATM layer address information of the corresponding terminal is returned. On the other hand, when the address is other than the own network, the requested cell is transferred to a preset upper ARS, which is ARS481 in this example.

(2) The ARS responds only to a request that wants to send a datagram to a terminal that is not the network, that is, belongs to another sub-network, and sends a resolution request to the terminal in its own network. The response to is different when each terminal to be transferred replies depending on whether the broadcast channel is used for address resolution or the point-point connection is used. When the broadcast channel is used, after the address is screened, the request cell is fetched and the request cell is transferred to the upper ARS. On the other hand, when the point-to-point connection is used, in principle, the higher AR is unconditionally
S, the cell can be transferred to the ARS 481 in this example.

In the example of FIG. 56, the ARS 481 that has received the address resolution request cell checks whether or not the address contained in the own network and the address of the request cell exist in the address space. When there is no address corresponding to the address entry,
Judge as an address for the public network. In the example, since the destination is the terminal 47D, the ARS 471 is the network 474.
It can recognize that the address of the requesting cell exists in the address space of the network (ie, network 474).
You can use the address space information that you have). The ARS481 that has analyzed the address of the terminal 47D is IWU4
VC for ATM connection from 76 to CLSF494
I / VPI information (VCI / when viewed from IWU476
(VPI information) to ARS482.

ARS482 is CLSF in IWU476
VCI which is the identification information of the ATM connection to be relayed to the ATM connection of 494.
/ Respond VPI. By using this VCI / VPI, the terminal 47A can directly deliver the datagram to the CLSF 494. In the example of FIG. 57 in which the ARS 482 can autonomously perform address resolution, in response to the address resolution request given through the ATM connection 581, the resolution information (AR response) is directly sent to the terminal 47A. To the ATM connection 582.

The datagram transfer in this embodiment is performed as follows.

The terminal 47A uses the ATM connection 57.
5, 583 is used to transfer the cell (having datagram information) to the CLS 494. The IWUs 476 and 478 perform the ATM connection relaying by rewriting the VCI / VPI information of the received cell. Since this processing is performed as processing of the ATM layer without raising it to the upper layer, the ATM passing through the IWU 476 and 478 is used.
The connections 575 and 583 can be regarded as one ATM connection without an ATM termination point.

The CLSF 494, which is the termination point of the ATM connections 575 and 583, performs the processing of the network layer. The CLSF 494 analyzes the network address and sends the datagram to the ATM connection 57.
6, relaying to 584 and transferring to the terminal 47D.

As described above, the ATM connection is used by the terminal 4
7A to CLSF494 and CLSF494 to terminal 4
Two of 7D, which are terminated only once.

(Embodiment 5-2) In case of using VPI routing ATM network-No. 1

First, the ATM layer address allocation method in this embodiment will be described. When performing VPI routing, the VPI field is the destination UNI
(Described as VPI-F). The coding method of the VCI field needs to be defined as follows. The coding of the VCI field discussed here relates to the transfer of cells related to connectionless communication, and the coding here is not necessarily required for other applications (such as connection-oriented connections). No need to use. That is, in general, the VCI field coding method can be performed by negotiation between the receiving terminal and the transmitting terminal. The 16-bit VCI field is defined to be composed of two 8-bit subfields, and these are defined as VCI-F1 and VCI.
-It is described as F2.

In this embodiment, the ATM connection is set as follows. The setting of the ATM connection associated with the address resolution shown in FIGS. 58 to 60 will be described. Each ARS 481-484 is at least each A
It manages address information of terminals or networks accommodated by the networks 471 to 474 to which the RS belongs.

FIG. 58 shows a case where the ARS 481 shown in FIG. 48 takes the initiative (becomes the root) to manage the address information of each sub-network. VCI / VPI
The information is rewritten by the IWU and the ATM connection is relayed. For example, from ARS482 to AR
ATM connection to S481 is connection 59
1, 592. V of connection 591
PI-F is VP which is the access address of IWU476
I _476-2 and VCI-F1 is VPI ₄₈₂ which is the access address of ARS482. VCI-F2 is
In principle, it can be any value, but IWU
476 is coded so that the information inside the VCI-F2 can identify that the receiving cell is to be relayed to the connection 592.
On the other hand, VPI-F of connection 592 is ARS481.
Access address of VPI ₄₈₁ and VCI-
F1 is VPI which is the access address of IWU476
_476-1 . In addition, VCI-F for both connections
In principle, 2 can be any value. VPI _476-1 is an IWU for network 471.
476 access address (VPI) and VPI _476-2 are _IWU 476 access addresses (VPI) for the network 472.

In IWU476, the VCI of the received cell
-F2 and VCI-F1 information set, connection 5
The VCI / VPI information to be written in the cell 92 is analyzed. Therefore, the IWU 476 has a VCI field (16 bits) as a table entry, and as a result V
It has a function of analyzing CI / VPI information. The VPI-Fs of the cells of the connection 592 are VCI-F1 and VCI-
It is analyzed by the combination of F2. VCI-F1 has V
PI _476-1 is written. Also, VCI-F2 is A
It is coded as an identifier of an ATM connection between RS482 and ARS481. The value of VCI-F2 is the ATM connection (connections 591, 59).
Determined when setting 2). The VCI-F2 assignment is made by subnetwork (networks 471, 47
2) The process that manages the VCI-F2 within the terminal 2 may be used, and the terminal (ARS481 and IWU47)
It may be a process that manages the value of VCI-F2 in 6).

59 and 60 will be described. This is the case where each ARS shown in FIG. 51 manages the address information of each sub-network independently. For example, ARS
ATM connection 617 from 482 to ARS 484
Is formed from connections 6021, 6041, 6061. VPI-F of connection 6021 is IW
VPI 476-2, which is the access address of U476, and VCI-F1 is VPI ₄₈₂ , which is the access address of ARS482. VCI-F2 is VCI-F which is an identification number assigned to the connection 6021.
The connection is identified by the combination of 1 and VCI-F2. VPI-F of connection 6061 is IWU47
VPI _478-1 which is an access address of 8 and VC
I-F1 is a VP which is an access address of IWU476
I _476-1 . VCI-F2 is connection 606
This is a value set when 1 is set. Connection 604
VPI-F of No. 1 is VPI ₄₈₄ which is an access address of ARS484, and VCI-F1 is VPI _478-1 which is an access address of _IWU478 . VCI-F
2 is a value set when the connection 6041 is set.

For example, the IWU 478 analyzes the VCI / VPI information to be written in the cell of the connection 6041 from the set of VCI-F2 and VCI-F1 information of the received cell. The IWU 478 has a VCI field (16 bits) as a table entry, and as a result has a function of analyzing VCI / VPI information.

VPI-F of cell of connection 6041
Is analyzed with a combination of VCI-F1 and VCI-F2. VPI _478-1 is written in VCI-F1. Further, VCI-F2 is from ARS482 to ARS48.
It is coded as an identifier of an ATM connection with 1 (parsed from VCI field information). VCI
-F2 value is ATM connection (connection 60
21, 6041, 6061) is set. V
The CI-F2 assignment is based on the VCI-F within the sub-network (networks 471, 472, 474).
It does not matter even if it is the process that manages the 2nd, the terminal (ARS481, IWU476, ARS484) is VC
A process that manages the value of I-F2 may be used.

By the method of setting the VCI / VPI field as described above, the information over a plurality of cells is ARS.
When data is transferred to another ARS, the data can be reassembled on the receiving side without any problem. It is necessary to use the identification field of the upper layer for data identification such as from which terminal the data is transferred, or the data is related to the address resolution protocol.

FIG. 61 shows the setting of the ATM connection required to transfer the datagram from the terminal 47A to the terminal 47F, the public network 475 and the terminal 47D. The two methods are shown below.

(1) First, the transfer of a datagram from the terminal 47A to the terminal 47F will be described. In this case, two ATs
Formed from M connections. One is from the terminal 47A to the CLSF 491 and the other is from connection 621 to 624, and the other is from the CLSF 491 to the terminal 47F.
Connection 625 to. Terminal 47A is IWU
The following cells are transferred to 476. That is, VPI
-F is VPI which is the access address of IWU476
_476-2 , VCI-F1 is the access address of the terminal 47A, VPI _47A , and VCI-F2 is the connection 621.
Each has the value set at the time of setting. IWU476
The VCI of the cell received at is analyzed and the corresponding VPI is
-F and VCI-F2 are analyzed. VCI-F1
Is written with VPI _476-1 which is an access address for the network 471 of the IWU 476. Note that VCI-F2 is a value determined when the connection 624 is set up, and it is also possible to copy and write the VCI-F1 value of the cell received by the IWU 476, that is, the VPI _47A that is the access address of the terminal 47A. is there.

The datagram arriving at the CLSF 491 is once cell reassembled and the ATM connection is terminated. The CLSF 491 analyzes the address information of the upper layer and recognizes that the destination of the datagram is the terminal 47F. Therefore, the CLSF 491 generates the following cell and transfers the datagram to the terminal 47F. V
PI-F is VPI which is the access address of the terminal 47F.
_47F and VCI-F1 are VPI ₄₉₁ and VCI-F2 which are access addresses of CLSF ₄₉₁ and connection 62, respectively.
It is an identification number assigned to No. 5. In addition, terminal 47F
Can uniquely identify the datagram to which the cell belongs from VCI-F1 and VCI-F2. That is,
Datagram reassembly is possible.

Next, the transfer of a datagram from the terminal 47A to the public network 475 will be described. In this case, one ATM
Connection (connection 622 + 626 + 627)
Formed from. The terminal 47A transfers the following cell to the IWU 476. That is, VPI-F is VPI
_476-2 and VCI-F1 have VPI _47A , and VCI-F2 has the value set when the connection 622 is set. The VCI of the cell received by the IWU 476 is analyzed and the corresponding VPI-F and VCI-F2 are analyzed. VCI-F1 is a network 47 of IWU476.
VPI _476-1 which is the access address for 1 is written. The VCI-F2 is connected to the connection 626.
Is a value determined when is set, and the VCI-F1 value of the cell received by the IWU 476, that is, the terminal 47A.
It is also possible to copy and write VPI _47A , which is the access address of. The IWU 479 receives the V of the received cell.
From the CI information, the VCI / VCI assigned to the ATM connection 627 defined in the public network 475.
Is written and the cell is transferred to the public network 475.

Finally, the transfer of datagrams from the terminals 47A to 47D will be described. It is made up of two ATM connections. One is the connection 623, 628, 629 from the terminal 47A to the CLSF 494, and the other is C
It is the connection 62A from the LSF 494 to the terminal 47D. The terminal 47A transfers the following cell to the IWU 476. That is, VPI-F is the access address of _IWU476 , VPI _476-2 , and VCI-F1 is the terminal 4
7A access address VPI _47A , VCI-F
2 has a value set when the connection 623 is set. The VCI of the cell received by the IWU 476 is analyzed and the corresponding VPI-F and VCI-F2 are analyzed. VCI-F1 is an access address for the network 471 of the IWU 476, VPI _476-1.
Is written. Note that VCI-F2 is a value that is determined when the connection 628 is set, and is IWU4.
It is also possible to copy and write the VCI-F1 value of the cell received by 76, that is, the VPI _47A which is the access address of the terminal 47A.

Next, the V of the cell received by IWU478
The CI is analyzed and the corresponding VPI-F, VCI-F1 and VCI-F2 are analyzed. VCI / VPI is C
The LSF 494 needs to be allocated so that cells from all terminals in the network (terminals that can transfer datagrams to the CLSF 494) can be identified even if they arrive at the same time.

The datagram arriving at the CLSF 494 is once cell-reassembled to terminate the ATM connection. The CLSF 494 analyzes the address information of the upper layer and recognizes that the destination of the datagram is the terminal 47D. Therefore, the CLSF 494 generates the following cell and transfers the datagram to the terminal 47D. That is, VPI-F is the access address of the terminal 47D, VPI _47D , VCI-F1 is the access address of CLSF ₄₉₄ , VPI ₄₉₄ , and VCI-F2 is the identification number assigned to the connection 62A. In addition,
The terminal 47D can uniquely identify the datagram to which the cell belongs from the VCI-F1 and the VCI-F2. That is, the datagram can be reassembled.

(2) Each CLSF has acquired a VPI address, and all connections identified by the VPI are ATM connections used for cell transfer related to datagram communication (connectionless communication). To do. That is, the CLSF server needs an ATM connection (not a connectionless connection) in order for itself to communicate with another terminal / server. That is, the CLSF needs to acquire at least two or more access addresses (VPI) at boot time.

Similarly, all IWUs also acquire at least two access addresses (VPI) at boot time.
One VPI is used for a connectionless communication cell. That is, when transferring a cell of a datagram relating to connectionless communication to an external network, each terminal attaches a VPI (for IWU) defined for connectionless communication to the cell and inserts the cell into the network.

At this time, the following method is used as the coding method of the VCI field of the cell for connectionless communication. The VCI field is divided into two 8-bit subfields (VCI-F1 and VCI).
-F2: Does not mention the defined position of the field).

Next, a coding method of cells transferred in the external sub-network will be described. This is the coding of the VCI field when the cell is transferred from the sub-network to which the terminal belongs to the external sub-network via the IWU. In VCI-F1, the identification number of the sub-network to which the source terminal belongs is written,
In VCI-F2, the identification number of the source terminal within the sub-network is written. For example, each IWU in the network 471 is used as the identification number of the sub-network.
It is also possible to use the access address (VPI) of the network as the identification address of the sub-network (network 47).
1 itself is coded appropriately). The terminal identification number may be the access address (VPI) of the terminal in each sub-network. For example, the terminal 47D transferred within the external sub-network
The VCI field of the cell for connectionless communication issued from is VCI-F1 = VPI _478-1 , VCI-F2 =
Can be VPI _47D .

Next, a coding method of cells transferred within the own sub-network will be described. This is the coding of the VCI field when the cell is transferred to the IWU of the sub-network to which the terminal belongs. VC
The identification number of the sub-network to which the destination terminal belongs is written in I-F1, and the identification number of the source terminal in the sub-network is written in VCI-F2. For example,
The VCI-F2 field of the cell for connectionless communication transmitted from the terminal 47D transferred in the own network can be set to VPI _47D .

With the above-mentioned configuration, the terminal can obtain the datagram (plurality of packets) as long as it obtains the identification number of the subnetwork to which the destination terminal belongs in the address resolution procedure performed prior to the datagram transfer. Alternatively, one cell) can be transferred. Less than,
The transfer of this datagram will be described.

First, the transfer of a datagram from the terminal 47A to the terminal 47F will be described. Terminal 47A is IWU47
The following cells are transferred to 6. VPI-F is IWU4
76 access addresses VPI _476-2 , VCI-
F1 is an identification number of the network 471 (for example, CLSF
The use of VPI ₄₉₁₎ is a 491 access address of the possible), VCI-F2 is set to VPI _{47 A} which is the access address of the terminal 47A.

The VCI of the cell received by the IWU 476 is analyzed and the corresponding VPI-F and VCI-F2 are analyzed. For example, in the case of the embodiment in which the access address VPI ₄₉₁ of CLSF ₄₉₁ is written in VCI-F1, the VPI-F of the cell to be output can copy the VPI ₄₉₁ which is the VCI-F1 information of the received cell. ,realizable. VPI _476-1, which is an access address for the network 471 of the _{IWU 476,} is written in the VCI-F1. VCI-F2 can be set transparently. That is, for example, CL is added to VCI-F1 of the cell transferred from the terminal 47A.
In the embodiment where the access address VPI _{49 1} of SF491 is written, (1) VCI-F receiving cell
1 is copied to the VPI-F of the sending cell, (2) VCI-F2 of the receiving cell is copied to the VCI-F2 of the sending cell,
(3) Cell relaying is realized by the procedure of writing the IWU access address VPI _476-1 in the VCI-F1 of the sending cell.

The datagram arriving at the CLSF 491 is cell reassembled and the ATM connection is terminated. The CLSF 491 analyzes the address information of the upper layer and recognizes that the destination of the datagram is the terminal 47F. Therefore, the CLSF 491 creates a cell whose VPI-F is the VPI _47F which is the access address of the terminal 47F, and transfers the datagram to the terminal 47F. In addition, CSLF491 is VCI-F1 and VCI-F.
From 2, the datagram to which the cell belongs can be uniquely identified (the datagram can be reassembled). Therefore, it is possible to perform relaying of datagram (cell) in a pipeline manner.

Next, the transfer of a datagram from the terminal 47A to the public network 475 will be described. Terminal 47A is IWU4
The following cells are transferred to 76. VPI-F is IWU
476 access address VPI _476-2 , VCI-
F1 is set to the identification number of the public network 475 (for example, VPI ₄₇₉ which is an access address of IWU479 can be used), and VCI-F2 is set to VPI _47A which is an access address of the terminal 47A.

The VCI of the cell received by the IWU 76 is analyzed, and the corresponding VPI-F and VCI-F2 are analyzed. For example, in the case of the embodiment the access address VPI ₄₇₉ of IWU479 the VCI-F1 is written, VPI-F cells to be output, by copying the VPI ₄₇₉ is VCI-F1 information of the received cell ,realizable. VCI-F1 has VW which is an access address for the network 471 of IWU476.
PI _476-1 is written. VCI-F2 can be set transparently. That is, for example, the IWU is added to the VCI-F1 of the cell transferred from the terminal 47A.
In the case of the embodiment in which the access address VPI _{479 of 479} is written, (1) the VCI-F1 of the reception cell is copied to the VPI-F of the transmission cell, and (2) the VC of the reception cell.
Cell relaying is realized by the procedure of copying I-F2 to VCI-F2 of the sending cell, and (3) writing VPI _476-1 , which is the IWU access address, in VCI-F1 of the sending cell. . The IWU 479 uses the VCI information of the received cell to assign the VC assigned to the ATM connection 627 defined in the public network 475.
Write I / VPI and transfer cells to public network 475.

Finally, the transfer of the datagram from the terminal 47A to the terminal 47D will be described. Terminal 47A is IWU47
The following cells are transferred to 6. VPI-F is IWU4
76 access addresses VPI _476-2 , VCI-
F1 is the identification number of the network 474 (for example, IWU4
It is also possible to use VPI _478-1 which is the access address of 78), and VCI-F2 is set to VPI _47A which is the access address of the terminal 47A.

The VCI of the cell received by the IWU 476 is analyzed and the corresponding VPI-F and VCI-F2 are analyzed. For example, in the embodiment in which the access address VPI _{478-1 of the IWU478} is written in the VCI-F1, the VPI-F of the cell to be output copies the VPI _478-1 which is the VCI-F1 information of the received cell. It can be realized by doing. VCI-F1 is a VP which is an access address for the network 471 of the IWU 476.
I _476-1 is written. VCI-F2 can be set transparently. That is, for example, IWU4 is added to VCI-F1 of the cell transferred from the terminal 47A.
In the case of the embodiment in which the access address VPI _{478-1 of} 78 is written, (1) the VCI-F1 of the reception cell is copied to the VPI-F of the transmission cell, and (2) the VC of the reception cell.
Cell relaying is realized by the procedure of copying I-F2 to VCI-F2 of the sending cell and (3) writing VPI _476-1 which is the access address of the IWU in VCI-F1 of the sending cell.

Next, the V of the cell received by the IWU 478 is received.
The CI is analyzed and the corresponding VPI-F, VCI-F1 and VCI-F2 are analyzed. IWU478 to CL
The VCI field of the cell transferred to the SF494 can transparently set the VCI field information of the received cell. That is, VCI-F
1 = VPI _476-1 and VCI-F2 = VPI _47A . The VPI-F is set to VPI ₄₉₄ which is the access address of CLSF494. CLSF
The datagram arriving at 494 is once cell-reassembled to terminate the ATM connection. CLSF
494 analyzes the address information of the upper layer and recognizes that the destination of the datagram is the terminal 47D. Also,
The CLSF 494 creates a cell whose VPI-F is VPI _47D which is the terminal 47D access address and transfers the datagram to the terminal 47D. The terminal 47D can uniquely identify the datagram to which the cell belongs from the VCI-F1 and VCI-F2. That is,
Datagram reassembly is possible. Specifically, for example, from the VCI-F1, the subnetwork to which the transmission source terminal belongs or the IWU accommodating the subnetwork is converted to VC.
It can be known from I-F2 as an identification number in the sub-network.

(Embodiment 5-3) In case of using general ATM network-No. 2

FIG. 62 shows a schematic diagram of the network architecture of this embodiment. This network has 2
It consists of a hierarchical network. Each network 631-635 is internetworked via IWUs 636-639. Network 631
The public network 635 and the public network 635 are connected via an IWU 639. The IWUs 636 to 639 can realize ATM cell relaying without terminating the ATM connection. That is, the VCI / VP of the received cell
It has a function of converting I into VCI / VPI assigned to the corresponding ATM connection in the adjacent network. CLSF-O, CLSF-I and AR
S can also be mounted in the same device. Furthermore, these can be implemented on the IWU.

64 and 65 show the setting of the ATM connection associated with the address resolution.
Each ARS manages at least the address information of the terminal or network accommodated by the network to which the ARS belongs.

In FIG. 63, from terminal 63A to (1) terminal 63
C, (2) public network 635, (3) ATM connections 641-6 required to transfer the datagram to the terminal 63B
46 settings are shown. CLSF-O63M to CLSF-
An ATM connection (one-way ATM connection) to the I63L, CLSF-I63J and the public network 635 is set. Similar connections are set for other sub-networks. The ATM connection set between CLSF-I and CLSF-O is shown in FIG. In the case of connectionless communication from the public network 635 to terminals belonging to the defined networks 631 to 634, the ATM connection for connectionless communication from the public network 635 is from the public network 635 existing in the network 631. Terminates ATM connection for connectionless communication,
It is terminated at the server for relaying datagrams. For the server terminating the ATM connection relating to this connectionless, to the target terminal using the same procedure as the datagram transfer from the terminal in the network to the terminal in the other network, which will be described below,
Transferred from this server.

The protocol of the terminal in this embodiment will be described. When the terminal determines that the datagram is destined for the external subnetwork, the terminal transfers the datagram to CLSF-O. In addition, the terminal and CLS
It is assumed that an ATM connection has already been established with FO. Each terminal has the information (address mask, etc.) of the address space of the sub-network to which it belongs, and can judge whether the destination terminal is in its own sub-network or an external sub-network. .

In the case of the network configuration shown in FIG. 62, the following three methods can be used as the datagram delivery method.

(1) CLSF-O and CLSF-I are at the same access point, and a star-shaped ATM connection is set between CLSF and the terminal. When the terminal transfers the datagram, the terminal transfers the cell to the CLSF. All datagram delivery is CLSF
Do. That is, communication between terminals in the sub-network also goes through the CLSF once.

(2) Communication between terminals in the sub-network is realized without CLSF, and communication with terminals in the external network is realized via CLSF-O.

(3) CLSF-O is used for communication with terminals in the external network, and CLSF-I is used for communication with terminals in the own network.

There are two types of protocol of the address resolution server in this embodiment, “backbone ARS initiative” and “front end ARS manual”.
Each is as follows.

(I) Backbone ARS initiative ARS existing in each network and network 631
A star-shaped ATM connection (bidirectional communication channel) is formed between the ARS 63G and the ARS 63G (see FIG. 6).
4). For example, in order to transfer a datagram from the terminal 63A to the terminal 63B, the CLSF-O63M is a CLSF-O.
ATM set between 63M and CLSF-I63J
In order to use a connection, V of that connection
It is necessary to obtain PI / VCI information. CLSF-O
In order to acquire VCI / VPI, the 63M connects the terminal 6 to the ARS 63D which is the ARS of its own network 632.
The address resolution request cell having the address information of 3B is transferred (address information written in the received datagram). A who received the request cell
The RS 63D analyzes the address of the destination terminal written in the received cell, and when the address cannot be resolved by the information held by the ARS 63D, the ATM connection already set to the ARS 63G existing in the network 631. 651 is used to relay the address resolution request cell.

The ARS 63G uses the address information of the destination terminal 63B possessed by the received cell to transfer the datagram to the CLSF (existing in the network 633) to which the datagram should be transferred.
The I information (VCI / VPI information will be described later) is analyzed, and the VCI / VPI information is transferred to the ARS 63D. The ARS63D that received the VCI / VPI information
Based on the VCI / VPI information, CLSF-O63M replies with the VCI / VPI information to be used (AR response).

Address resolution in ARS63G is performed as follows. The ARS 63G has address information (address space information) of the terminal accommodated in the own network 631 and information of the address space of the sub-networks 632 to 634. The ARS 63G compares the address written in the received address resolution request cell with the address space information of each sub-network to analyze the corresponding transfer destination network.

There are the following two methods for identifying the datagram for the public network 635.

(A) It indicates whether the address information written in the address resolution cell is explicitly a datagram intended for the public network 635 or a datagram not intended for the public network. In other words, when the terminal knows whether it is for the public network or not when requesting the address resolution, the terminal can explicitly identify whether the ARS is for the public or not. Transfer the session cell to the ARS. When the address information is not the address for the public network 635, the ARS6
When the address does not exist in the 3G address entry, the information that the address does not exist is ARS6.
Sent to 3D.

(B) When the address held by the received address resolution request cell does not exist in the address entry of ARS63G, the address is public network 6
It is determined to belong to 35.

[0531] Thus, the ARS 63G has terminals and sub-networks 632 belonging to the network 631.
With address and address space information of ~ 634,
Performs address resolution. In addition, ARS63
G does not necessarily have to have the address information up to the terminal level of the sub-network other than the sub-network to which it belongs, and may have the information up to the network address level.

The address information (ATM layer) received by the ARS 63D from the ARS 63G is the identifier (VCI / VPI information of the ATM connection from the IWU 636 to the CLSF-I existing in the target subnet, and may also include the identification information of the upper layer). Yes) information. For example, when transferring a datagram from the terminal 63A to the terminal 63B, A for accessing CLSF-I63J is used.
The identifier of the TM connection 645 is notified (AR response), and when transferring the datagram to the terminal 63C, C
The identifier of the ATM connection 642 for accessing LSF-I63L is notified.

[0533] Note that the ARS63D uses the VCI / VPI information received from the ARS63G to check that the ATM connection is normally relayed by the IWU636.
The I / VPI information is notified to CLSF-O63M. CL
The VCI / VPI number notified to SF-O63M is I
It is rewritten to another VCI / VPI in WU636.

(Ii) Front-end ARS initiative ARS existing in each network and network 631
A star-shaped ATM connection as shown in FIG. 64 or a mesh-shaped ATM connection as shown in FIG. 65 is formed between the ARS 63G and the ARS 63G. Each ARS acquires the address space information and ATM connection information (VCI / VPI) of the external sub-network when viewed from its own sub-network by using the ATM connection defined in FIG. 64 or FIG. 65, respectively. In Figure 64, ARS63G is the master ARS.
It can be said that FIG. 65 is a distributed type in which each ARS operates independently.

When the network does not have three or more layers, it is more appropriate to use the backbone network as the master as shown in FIG. On the other hand, when there is no limitation on the hierarchy of the network, which of the forms shown in FIGS. 64 and 65 is selected depends on the form of the network or the form of management and the number of sub-networks existing in the network. For example, CLSF-O63M sends VCI / VPI to transfer the datagram to the terminal 63B.
CLSF-O63M to obtain ARS63D, which is the ARS63D which is the ARS of its own network 632.
The address resolution request cell having the address information of B is transferred. ARS6 that received this request cell
3D analyzes that the address of the destination terminal written in the received cell is the network 633,
The VCI / VPI information for transferring the datagram to the CLSF (existing in the network 633) to which the datagram is to be transferred (the VCI / VPI information will be described later) is transferred to CLSF-O63M (AR response).

Address resolution in ARS63D is performed as follows. The ARS 63D is the address information (address space information) of the terminal accommodated in the own network 632 and the sub-networks 631, 63.
It has information on the address space of 3,634. ARS
63D compares the address written in the received address resolution request cell with the address space information of each sub-network, and analyzes the corresponding transfer destination network.

There are the following two methods for identifying the datagram for the public network 635.

(A) It indicates whether the address information written in the address resolution cell is a datagram for the public network 635 or not for the public network. In other words, when the terminal knows whether it is for the public network or not when requesting the address resolution, the terminal can explicitly identify whether the ARS is for the public or not. Transfer the solution cell to the ARS. When the address information is not the address for the public network 635, the ARS
If the address does not exist in the 63D address entry, it is determined that the address does not exist.

(B) When the address held by the received address resolution request cell does not exist in the address entry of ARS63D, the address is public network 6
It is determined to belong to 35.

[0540] As described above, the ARS 63D includes terminals and sub-networks 63 belonging to the network 632.
It has information of addresses 1,633 and 634 and an address space, and performs address resolution. In addition,
The ARS 63D does not necessarily have to have address information up to the terminal level of a sub-network other than the sub-network to which the ARS 63D belongs, and may have information up to the network address level.

The address information (ATM layer) that the ARS 63D receives from another ARS is an identifier (VCI / VPI information of the ATM connection from the IWU 636 to the CLSF-I existing in the target subnet, and also includes the identification information of the upper layer). Information). For example,
An ATM for accessing CLSF-I63J when transferring a datagram from the terminal 63A to the terminal 63B.
The identifier of the connection 645 is notified (AR response), and when transferring the datagram to the terminal 63C, CLSF-
ATM connection 64 for accessing I63L
Notify the identifier of 2.

The ARS 63D uses the VCI / VPI information received from other ARSs to identify the VCIs through which the ATM connection is normally relayed by the IWU 636.
/ VPI information is notified to CLSF-O63M. CLS
The VCI / VPI number notified to the F-O63M is the IW
It is rewritten to another VCI / VPI in U636. Between the ARSs, not only the exchange protocol of the address space information of each sub-network but also the routing protocol for the datagram communication (connectionless communication) between the sub-networks operates. In particular,
The ATM connection setting management as shown in FIG. 63 is performed. It should be noted that individual ATM connections are separated by IWU (closed inside the sub-network), and another ATM connection server process and routing server process are used for ATM connection route control and ATM connection management (for example, VCI / VPI).
Management), and ARS manages these servers and
It exchanges control messages with WU and manages ATM connections required for connectionless communication.

[0543] The routing to the destination terminal in this embodiment will be described. The final datagram delivery to each terminal is performed only for the network to which each CLSF-I belongs. That is, for example, CLSF-I63L is a terminal (network 6) belonging to the network 631.
32 to 635 do not service the datagram. Similarly, CLSF-I63J delivers the datagram only to the terminals in the network 633. If the datagram received by each CLSF does not have a network address in its address entry, or if the address of the received datagram is not an element of the network's network address space, then the datagram is incorrect. It is determined that the product has been delivered. The actions for delivery of erroneous datagrams are not discussed here. That is, each CL
The SF need only have the address information of the terminal of the network to which it belongs. When the address of the received datagram exists in the local network, an appropriate ATM
Select a connection to relay the datagram.

FIG. 67 shows an example of protocol processing when a datagram is transferred from the terminals 63A to 63B. The ATM connection is terminated with CLSF-O63M and CLSF-I63J. That is, CLSF
OSI layer 3 with -O63M and CLSF-I63J
Is terminated. Thus, when transferring a datagram to a terminal other than its own subnetwork,
Datagram delivery is achieved end-to-end with two ATM connection terminations.

(Embodiment 5-3-1) Next, a more specific embodiment will be described.

An example in which a datagram is transferred from the terminals 63A to 63B in FIG. 63 will be briefly described.

Address resolution in this embodiment is performed as follows.

When the terminal 63A analyzes that the terminal 63B belongs to the external sub-network when transferring the datagram to the terminal 63B, CLSF-O63
Transfer the datagram to M. The CLSF-O63M analyzes the address information of the received datagram, and the terminal 63
When it does not have the ATM layer address information for transferring the datagram to B (CLSF-I63J),
The address resolution request cell having the address information of the terminal 63B is transferred to the ARS 63D.

When the ARS63D has the information capable of resolution, the AR request (CLSF-O63
VC for transferring cells from M to CLSF-I63J
I / VPI information) is directly transferred. However, ARS6
When the resolution of the address cannot be performed in 3D, an appropriate ARS is accessed to perform the resolution. When the address resolution is completed, the result (AR response) is transferred to CLSF-O63M.

The datagram transfer in this embodiment is performed as follows.

The terminal 63A uses the ATM connection 641.
Cell with datagram information using CLSF-O6
Transfer to 3M. CLSF-O63M analyzes the address information of the datagram, converts the datagram into cells,
CLSF-I cell using ATM connection 645
Transfer to 63J. IWU636 and IWU637
Relays the ATM connection by rewriting the VCI / VPI information of the received cell. A
CLSF-I6, which is the termination point of the TM connection 645
In 3J, processing of the network layer is performed. CL
SF-I63J analyzes the network address,
The datagram is relayed to the ATM connection 646 and transferred to the terminal 63B.

As described above, the ATM connection is connected to the terminal 6
3A to CLSF-O63M, CLSF-O63M to CLSF-I63J, and CLSF-I63J and the terminal 63B, and the ATM connection is terminated twice.

(Embodiment 5-4) In case of using VPI routing ATM network-No. 2

Since the method of realizing the ATM connection set between the ARSs in this embodiment is the same as the method described above, its explanation is omitted here.

63 or 68, the terminal 63
Four methods will be described for setting the ATM connection required to transfer the datagram from A to the terminal 63B, the public network 635, and the terminal 63C.

ATM Connection Setting Method (1) First, the transfer of a datagram from the terminal 63A to the terminal 63C will be described. 3 ATM connections, ie
(1) Connection 691 from terminal 63A to CLSF-O63M, (2) CLSF-O63M to CLSF-I6
Connection to 3L 692, 693, (3) CLSF-
A connection 694 from the I63L to the terminal 63C is formed. The terminal 63A transfers a cell having VPI-F = VPI _63M . The VCI-F1 is the VPI _63A which is the access address of the terminal 63A. CLSF-O
The 63M transfers the following cells to the IWU 636.
VPI-F is V which is the access address of IWU636.
PI _636-2, VCI-F1 has VPI _63M which is the access address of the CLSF-O63M, VCI-F2 is set during connection 692 values, respectively.
The VCI of the cell received by the IWU 636 is parsed and the corresponding VPI-F and VCI-F2 are parsed. V
VPI _636-1, which is the access address for the network 631 of the _{IWU 636,} is written in CI-F1. The VCI-F2 is a value determined when the connection 693 is set, and the VCI-F1 value of the cell received by the IWU 636, that is, CLSF-O63.
It is also possible to copy and write VPI _63M which is the access address of M. The datagram arriving at CLSF-I63L is once cell reassembled to terminate the ATM connection. CLSF-I63L analyzes the address information of the upper layer and recognizes that the destination of the datagram is the terminal 63C. So CLSF-I
The 63L generates the following cell and transfers the datagram to the terminal 63C.

VPI-F is the access address of the terminal 63C, VPI _63C , and VCI-F1 is CLSF-I63.
VPI _63L and VCI-F2 which are L access addresses
Is an identification number assigned to the connection 694. The terminal 63C can uniquely identify the datagram to which the cell belongs from the VCI-F1 and VCI-F2. That is, the datagram can be reassembled.

Next, the transfer of the datagram from the terminal 63A to the public network 635 will be described. It is composed of two ATM connections 691 and 692, 695, 696.
The terminal 63A transfers a cell having VPI-F = VPI _63M . The CLSF-O63M transfers the following cells to the IWU 636. VPI-F is VPI _636-2 , VC
I-F1 is VPI _63M , VCI-F2 is connection 6
It has the value set at the time of setting 92. The VCI of the cell received by the IWU 636 is analyzed and the corresponding VPI-F
And VCI-F2 are analyzed. VCI-F1 is I
VPI _636-1, which is the access address of the _{WU 636} for the network 631, is written. In addition, VC
I-F2 is a value determined when the connection 695 is set, and VCI-of the cell received by the IWU 636.
The value of F1, i.e. it is also possible to write and copy the VPI _63M which is the access address of the CLSF-O63M. The IWU 639 uses the VCI information of the received cell to identify the ATM connection 696 defined in the public network 635.
Write VCI / VPI assigned to the cell and transfer the cell to the public network 635.

Finally, the transfer of datagrams from the terminals 63A to 63B will be described. 3 ATM connections,
That is, (1) connection 691 from terminal 63A to CLSF-O63M, (2) CLSF-O63M to CLS
Connection to F-I63J 692, 697, 69
8, (3) CLSF-I 63J to 63B connection 699. The terminal 63A has VPI-F = VPI _63M
Transfer the cell with. CLSF-O63M is IW
The following cells are transferred to U636. VPI-F is I
VPI _636-2 , V which is the access address of _WU636
CI-F1 has VPI _63M which is the access address of the CLSF-O63M, VCI-F2 is set during connection 692 values, respectively. The VCI of the cell received by the IWU 636 is analyzed and the corresponding VPI-
F and VCI-F2 are analyzed. VCI-F1 is
The VPI _636-1, which is the access address for the network 631 of the _{IWU 636,} is written. In addition, V
CI-F2 is a value determined when the connection 697 is set, and the VCI of the cell received by the IWU 636.
The value of -F1, i.e. it is also possible to write and copy the VPI _{63 M} which is the access address of the CLSF-O63M.

Next, the V of the cell received by the IWU 637 is received.
The CI is analyzed and the corresponding VPI-F, VCI-F1 and VCI-F2 are analyzed. VCI / VPI is C
LSF-I63J sends CLSF to all terminals / servers (CLSF etc.) in the network, that is, datagrams.
-It must be allocated so that cells from terminals capable of transferring to I63J can be identified even if they arrive at the same time.

The datagram arriving at CLSF-I63J is temporarily reassembled and the ATM connection is terminated. CLSF-I63J analyzes the address information of the upper layer, and the destination of the datagram is the terminal 63B.
Recognize that. Therefore, CLSF-I63J generates the following cell and transfers the datagram to the terminal 63B. VPI-F is the access address of the terminal 63B, VPI _63B , and VCI-F1 is CLSF-I63J.
Access addresses VPI _63J and VCI-F2 are identification numbers assigned to the connection 699.
The terminal 63B can uniquely identify the datagram to which the cell belongs from the VCI-F1 and VCI-F2. That is, the datagram can be reassembled.

ATM Connection Method (2) In CLSF-O, datagram reassembly is performed, but address resolution is performed by each terminal. VCI-F1 of cell in which the address information of the resolved target network is transferred from the terminal to CLSF-O
Write in. The cell transfer (datagram transfer) from CLSF-O cannot be executed in a pipeline manner. However, CLSF-O does not need to perform the resolution of the address of the network to which the destination terminal belongs from the address information in the received datagram.

Each IWU, CLSF-O and CLSF-
All I have acquired the VPI address, and the VPI
All the connections identified by are configured to be ATM connections used for cell transfer for datagram communication (connectionless communication). That is,
The CLSF server and IWU are themselves
An ATM connection (not a connectionless connection) is required to communicate with the server. That is, CLSF and IWU need to acquire at least two or more access addresses (VPI) at boot time.

At this time, the following method is used as the coding method of the VCI field of the cell for connectionless communication. The VCI field has two 8-bit subfields (VCI-F1 and VCI-F).
2: The definition position of the field is not mentioned).

[0565] A coding method of cells transferred in the external sub-network according to this embodiment will be described. This is the IWU from the subnetwork to which the terminal belongs.
It is the coding of the VCI field when a cell is transferred to an external sub-network via. VCI-
The identification number of the sub-network to which the source terminal belongs is written in F1, and the identification number of the source terminal in the sub-network is written in VCI-F2. For example,
Network 631 as a sub-network identification number
It is also possible to use the access address (VPI) of each IWU in the sub-network as the identification address (the network 631 itself is coded appropriately). The terminal identification number may be the access address (VPI) of the terminal in each sub-network. For example, the VCI field of the cell for connectionless communication issued from the terminal 63B is VCI-
F1 = VPI _637-1 and VCI-F2 = VPI _63B can be set.

(CLSF-O to IWU cell) VC
The identification number of the sub-network to which the source terminal belongs is written in I-F1, and the identification number in the sub-network of CLSF-O is written in VCI-F2. For example, the VCI-F2 field of the connectionless communication cell output from CLSF-O 63M can be VPI _63M .

(Terminal to CLSF-O cell) VCI
The identification number of the sub-network to which the destination terminal belongs is written in -F1, and the identification number of the source terminal in the sub-network is written in VCI-F2. For example, V of the cell for connectionless communication issued from the terminal 63B
The CI-F2 field may be VPI _63B .

With the above-mentioned configuration, the terminal can obtain the datagram (plurality of packets) as long as it obtains the identification number of the subnetwork to which the destination terminal belongs in the address resolution procedure performed prior to the datagram transfer. Alternatively, one cell) can be transferred as follows.

First, the transfer of a datagram from the terminal 63A to the terminal 63C will be described. The terminal 63A is CLSF-
Transfer the following cells to O63M. VPI-F is C
VP which is the access address of LSF-O63M
I _63M and VCI-F1 are set to the identification number of the network 631 (for example, VPI _63L which is the access address of CLSF-I _63L can be used), and VCI-F2 is set to the VPI _63A which is the access address of the terminal 63A.

The CLSF-O63M transfers the following cell to the IWU 636. VPI-F is IWU636
Set to VPI _636-2 which is the access address of V
The CI-F1 can copy the VCI-F1 of the reception cell as it is, and can identify the identification number of the network 631 (for example, VP which is an access address of CLSF-I63L).
I _63L can also be used). VCI-F
2 is V which is an access address of CLSF-O63M.
Set to PI _63M .

The VCI of the cell received by the IWU 636 is analyzed and the corresponding VPI-F and VCI-F2 are analyzed. For example, VCI-F1 with CLSF-I63L
In the embodiment in which the access address VPI _63L is written, the VPI-F of the cell to be output can be realized by copying the VPI _63L which is the VCI-F1 information of the received cell. For VCI-F1, IWU636
VPI _636-1, which is an access address for the network 631 in FIG. VCI-F2 can be set transparently. That is, for example, VCI-F of a cell transferred from CLSF-O63M
CLSF-I _63L access address VPI _63L
In the embodiment in which is written, (1) the VCI-F1 of the reception cell is copied to the VPI-F of the transmission cell,
(2) VCI-F2 of receiving cell is VCI-F2 of sending cell
(3) IWU is set in the VCI-F1 of the sending cell.
The cell relaying is realized by the procedure of writing VPI _636-1 which is the access address of the cell.

[0572] The datagram arriving at CLSF-I63L is once cell reassembled to terminate the ATM connection. CLSF-I63L analyzes the address information of the upper layer, and the destination of the datagram is the terminal 63C.
Recognize that. Therefore, CLSF-I63L uses VP whose VPI-F is the access address of the terminal 63C.
_Create a cell that is I _63C and forward the datagram to terminal 63C. The terminal 63C can uniquely identify the datagram to which the cell belongs, from the VCI-F1 and VCI-F2. That is, the datagram can be reassembled.

Next, the transfer of a datagram from the terminal 63A to the public network 635 will be described. The terminal 63A is CLSF
-Transfer the following cells to O63M. VPI-F is VPI which is the access address of CLSF-O63M.
_63M , VCI-F1 is an identification number of the network 635 (for example, VPI which is an access address of IWU639).
_{63 9} can also be used), VCI-F2 terminal 63A
It is set to VPI _63A which is the access address of.

The CLSF-O63M transfers the following cell to the IWU 636. VPI-F is IWU636
Set to VPI _636-2 which is the access address of V
The CI-F1 can copy the VCI-F1 of the reception cell as it is, and can identify the identification number (for example, I
It is also possible to use VPI ₆₃₉ which is the access address of WU ₆₃₉ ). VCI-F2 is CLS
Set to VPI _63M which is the access address of the F-O63M.

The VCI of the cell received by the IWU 636 is analyzed and the corresponding VPI-F and VCI-F2 are analyzed. For example, in the embodiment in which the access address VPI ₆₃₉ of the IWU ₆₃₉ is written in the VCI-F1, the VPI-F of the cell to be output is realized by copying the IWU 639 which is the VCI-F1 information of the received cell. it can. The VCI-F1 has V which is an access address for the network 631 of the IWU 636.
PI _636-1 is written. VCI-F2 can be set transparently. That is, for example, VCI-of a cell transferred from CLSF-O63M
In the case of the embodiment in which the access address VPI ₆₃₉ of the IWU ₆₃₉ is written in F1, (1) V of the receiving cell
CI-F1 is copied to VPI-F of the sending cell, (2) VCI-F2 of the receiving cell is copied to VCI-F2 of the sending cell, and (3) VCI-F1 of the sending cell is the access address of the IWU. By the procedure of writing a certain VPI _636-1 , cell relaying is realized. IWU639
Writes the VCI / VPI assigned to the ATM connection 696 defined in the public network 635 from the VCI information of the received cell, and transfers the cell to the public network 635.

Finally, the transfer of the datagram from the terminal 63A to the terminal 63B will be described. The terminal 63A is CLSF
-Transfer the following cells to O63M. VPI-F is VPI which is the access address of CLSF-O63M.
_63M and VCI-F1 are identification numbers of the network 633 (for example, VPI _63J which is an access address of CLSF- _I63J and V which is an access address of IWU 637).
(PI ₆₃₇ can be used), VCI-F2 is terminal 6
Set to VPI _63A which is the access address of 3A.

The CLSF-O63M transfers the following cell to the IWU 636. VPI-F is IWU636
Set to VPI _636-2 which is the access address of V
CI-F1 can be directly copy the VCI-F1 of the received cell, VPI _{637- 1} which is the access address of the identification number (e.g. IWU637 network 633
Can also be used). VCI-F2 is
VPI which is the access address of CLSF-O63M
Set to _63M . VC of cell received by IWU636
I was parsed and the corresponding VPI-F and VCI-F2
Is analyzed. For example, in the embodiment in which the access address VPI _637-1 of the IWU 637 is written in the VCI-F1, the VPI-F of the cell to be output copies the VPI _637-1 that is the VCI-F1 information of the received cell. It can be realized by doing. In VCI-F1, VPI _636-1, which is the access address for the network 631 of _{IWU 636,} is written. VCI-F2 can be set transparently. That is, for example, VCI-F of a cell transferred from CLSF-O63M
In the embodiment in which the access address VPI _637-1 of the IWU 637 is written in No. 1, (1) V of the receiving cell
CI-F1 is copied to VPI-F of the sending cell, (2) VCI-F2 of the receiving cell is copied to VCI-F2 of the sending cell, and (3) VCI-F1 of the sending cell is the access address of the IWU. By the procedure of writing a certain VPI _636-1 , cell relaying is realized.

[0578] Next, the V of the cell received by the IWU 637
The CI is analyzed and the corresponding VPI-F, VCI-F1 and VCI-F2 are analyzed. IWU637 to CL
The VCI field of the cell transferred to SF-I63J can transparently set the VCI field information of the received cell. That is, VC
I-F1 = VPI _636-1, can be a VCI-F2 = VPI _63M. Note that VPI-F is CLSF-I6.
VPI _63J which is an access address of 3J is set. The datagram arriving at CLSF-I63J is once reassembled and the ATM connection is terminated. CLSF-I63J analyzes the upper layer address information and recognizes that the destination of the datagram is the terminal 63B. The CLSF-I 63J creates a cell whose VPI-F is the VPI _63B which is the access address of the terminal 63B, and transfers the datagram to the terminal 63B. The terminal 63B can uniquely identify the datagram to which the cell belongs, from the VCI-F1 and VCI-F2. That is, the datagram can be reassembled.

ATM connection setting method (3) In the above method (2), the cell to which the datagram belongs is transferred in a pipeline manner. In CLSF-O, datagram reassembly is performed, but address resolution is performed by each terminal, and in CLSF-O, the resolution of the address of the network to which the destination terminal belongs is determined from the address information in the received datagram. No need to do. The resolved address information of the target network is written in the VCI-F1 of the cell transferred from the terminal to the CLSF-O.

At this time, the following method is used as the coding method of the VCI field of the cell for connectionless communication.

(Inside external sub-network-same as method 2) The VCI-F1 is written with the identification number of the sub-network to which the source terminal belongs, and the VCI-F2 is the identification number of the source terminal within the sub-network. Is written.

(CLSF-O to IWU cell) VC
The identification number of the sub-network to which the destination terminal belongs is written in I-F1, and the identification number of the source terminal in the sub-network is written in VCI-F2. For example,
The cell for the datagram output from the terminal 63A can have the VCI-F2 field as VPI _63A .

(Terminal to CLSF-O Cell-Method 2)
The same as the above), the identification number of the sub-network to which the destination terminal belongs is written in VCI-F1, and the identification number in the sub-network to which the source terminal belongs is written in VCI-F2.

First, the transfer of a datagram from the terminal 63A to the terminal 63C will be described. The terminal 63A is CLSF-
Transfer the following cells to O63M. VPI-F is C
VP which is the access address of LSF-O63M
I _63M and VCI-F1 are identification numbers of the network 631 (for example, VPI _63L which is an access address of CLSF-I _63L can be used), VCI-F2
Is set in the VPI _63A which is the access address of the terminal 63A.

The CLSF-O63M transfers the following cell to the IWU 636. VPI-F is IWU636
_Is set in the VPI _636-2 which is the access address of the.
The VCI-F1 and VCI-F2 can directly copy the information of the reception cell. Therefore, VCI-
F1 is an identification number of the network 631 (for example, CLSF
-It is also possible to use VPI _63L which is the access address of I63L), and VCI-F2 is set to VPI _63A which is the access address of terminal 63A. At this time, the cells can be sequentially transferred to the IWU 636 in a pipeline without once reassembling the datagram in the CLSF-O63M.

The VCI of the cell received by the IWU 636 is analyzed and the corresponding VPI-F and VCI-F2 are analyzed. For example, VCI-F1 with CLSF-I63L
In the embodiment in which the access address VPI _63L is written, the VPI-F of the cell to be output can be realized by copying the VPI _63L which is the VCI-F1 information of the received cell. For VCI-F1, IWU636
VPI _636-1, which is an access address for the network 631 in FIG. VCI-F2 can be set transparently. That is, for example, VCI-F of a cell transferred from CLSF-O63M
CLSF-I _63L access address VPI _63L
In the embodiment in which is written, (1) the VCI-F1 of the reception cell is copied to the VPI-F of the transmission cell,
(2) VCI-F2 of receiving cell is VCI-F2 of sending cell
Then, (3) the cell relaying is realized by the procedure of (3) writing the IWU access address VPI _636-1 in the VCI-F1 of the transmission cell.

The datagram arriving at CLSF-I63L is temporarily reassembled and the ATM connection is terminated. CLSF-I63L analyzes the address information of the upper layer, and the destination of the datagram is the terminal 63C.
Recognize that. Therefore, CLSF-I63L uses VP whose VPI-F is the access address of the terminal 63C.
_Create a cell that is I _63C and forward the datagram to terminal 63C. The terminal 63C can uniquely identify the datagram to which the cell belongs, from the VCI-F1 and VCI-F2. That is, the datagram can be reassembled.

Next, the data from the terminal 63A to the public network 635 is transferred.
The transfer of the datagram will be described. The terminal 63A is CLSF
-Transfer the following cells to O63M. VPI-F
VPI which is the access address of CLSF-O63M
_63M, VCI-F1 is an identification number of the public network 635 (for example,
VPI which is the access address of IWU639₆₃₉For
VCI-F2 can access the terminal 63A.
VPI which is address _63ASet to.

The CLSF-O63M transfers the following cell to the IWU 636. VPI-F is IWU636
_Is set in the VPI _636-2 which is the access address of the.
The VCI-F1 and VCI-F2 can directly copy the information of the reception cell. Therefore, VCI-
F1 is set to the identification number of the public network 635 (for example, VPI ₆₃₉ which is the access address of IWU ₆₃₉ can be used), and VCI-F2 is set to the VPI _63A which is the access address of the terminal 63A. At this time, CLSF
-In O63M, IWs of cells are sequentially pipelined without once reassembling datagrams.
Can be transferred to U636.

The VCI of the cell received by the IWU 636 is analyzed and the corresponding VPI-F and VCI-F2 are analyzed. For example, in the case of the embodiment in which the access address VPI ₆₃₉ of the IWU ₆₃₉ is written in the VCI-F1, the VPI-F of the cell to output outputs the IWU ₆₃₉ which is the VCI-F1 information of the received cell. realizable. VPI _636-1, which is the access address for the network 631 of the _{IWU 636,} is written in the VCI-F1. VCI-F2 can be set transparently. That is, for example, VCI-F of a cell transferred from CLSF-O63M
In the case of the embodiment in which the access address VPI ₆₃₉ of the IWU ₆₃₉ is written in No. 1, (1) VC of the receiving cell
I-F1 is copied to the VPI-F of the sending cell, (2) VCI-F2 of the receiving cell is copied to VCI-F2 of the sending cell, and (3) VCI-F1 of the sending cell is set to the access address of the IWU. The cell relaying is realized by the procedure of writing VPI _636-1 .

The IWU 639 writes the VCI / VPI assigned to the ATM connection 696 defined in the public network 635 from the VCI information of the received cell, and transfers the cell to the public network 635.

Finally, the transfer of the datagram from the terminal 63A to the terminal 63B will be described. The terminal 63A is CLSF
-Transfer the following cells to O63M. VPI-F is VPI which is the access address of CLSF-O63M.
_63M and VCI-F1 are set to the identification number of the network 633 (for example, VPI _63J which is the access address of CLSF- _I63J can be used), and VCI-F2 is set to the VPI _63A which is the access address of the terminal 63A.

The CLSF-O63M transfers the following cell to the IWU 636. VPI-F is IWU636
_Is set in the VPI _636-2 which is the access address of the.
The VCI-F1 and VCI-F2 can directly copy the information of the reception cell. Therefore, VCI-
F1 is the identification number of the network 633 (for example, IWU6
VPI _637-1 which is the access address of 37 can be used), and VCI-F2 is set to VPI _63A which is the access address of terminal 63A. At this time, CL
In the SF-O63M, cells can be sequentially transferred to the IWU 636 in a pipeline manner without once reassembling the datagram. The VCI of the cell received by the IWU 636 is analyzed and the corresponding VPI-
F and VCI-F2 are analyzed. For example, VCI-
In the case of the embodiment in which the access address VPI _637-1 of the IWU 637 is written in F1, the VPI-F of the cell to be output can copy the VPI _637-1 that is the VCI-F1 information of the received cell. realizable. VCI-
VPI _636-1, which is an access address for the network 631 of the IWU _636, is written in F1.
VCI-F2 can be set transparently. That is, for example, in the case of the embodiment in which the access address VPI _{637-1 of the} IWU 637 is written in the VCI-F1 of the cell transferred from the CLSF-O 63M, (1) the VCI-F1 of the reception cell is set to the VPI of the transmission cell.
-F, (2) Copy VCI-F2 of the receiving cell to VCI-F2 of the sending cell, and (3) VCI- of the sending cell.
V1 which is the access address of IWU is in F1.
The procedure of writing _636-1 realizes cell relaying.

Next, the V of the cell received by the IWU 637 is received.
The CI is analyzed and the corresponding VPI-F, VCI-F1 and VCI-F2 are analyzed. IWU637 to CL
The VCI field of the cell transferred to SF-I63J can transparently set the VCI field information of the received cell. That is, VC
I-F1 = VPI _636-1, can be a VCI-F2 = VPI _63M. Note that VPI-F is CLSF-I.
VPI _63J, which is the access address of _63J, is set.

The datagram arriving at CLSF-I63J is once reassembled and the ATM connection is terminated. CLSF-I63J analyzes the address information of the upper layer, and the destination of the datagram is the terminal 63B.
Recognize that. CLSF-I63J is VPI-
A cell is generated in which F is VPI _63B , which is the access address of terminal 63B, and the datagram is transferred to terminal 63B. Note that the terminal 63B has VCI-F1 and VCI-
The datagram to which the cell belongs can be uniquely identified from F2. That is, the datagram can be reassembled.

ATM connection setting method (4) This is an example of the method (2) in which datagram transfer to different sub-networks is performed in a pipeline manner. Datagram transfer from a terminal belonging to the same subnetwork to a terminal within the same subnetwork cannot be pipelined, but pipeline transfer is possible if the destination subnetwork is different. In this case, CLSF-O needs to have some buffer space.

Although CLSF-O reassembles datagrams, each terminal performs address resolution. Therefore, CLSF-O uses the address information in the received datagram to determine the address of the network in which the destination terminal exists. There is no need to perform resolution. The resolved target network address information is written in the VCI-F1 of the cell transferred from the terminal to the CLSF-O. The datagram transfer procedure in CLSF-O will be described below.

Step 1: Receive a cell from the terminal (leading cell for datagram).

Step 2: Analyze the target sub-network address information written in VCI-F1.

Step 3: Check whether or not there is currently performing datagram transfer to the analyzed sub-network.

Step 4: CLSF-O can recognize the end of datagram transfer by using an identification code higher than the ATM layer (for example, payload type coding for AAL5). When no other datagram is transferred to the analyzed sub-network, the received cell is relayed to the target sub-network. Receive cells are relayed in CLSF-O without being reassembled once; pipeline transfer.

Step 5: On the other hand, when another datagram is being transferred to the analyzed sub-network from another terminal, the received cell must be buffered until the datagram transfer is completed. There is.
When the completion of the transfer of other datagrams is confirmed, the buffered cells are transferred sequentially. At this time, the buffered cell (datagram) does not need to be reassembled, and the transfer of the first cell must start before the last cell of the datagram to which the buffered cell belongs arrives. You can Further, if an appropriate protocol is defined between CLSF-O and the terminal, it is possible to perform flow control so that buffered cells are not discarded due to buffer overflow.

In the present embodiment, the following method is used as the coding method of the VCI field of the cell for connectionless communication.

(Inside external sub-network-same as method 2) The identification number of the sub-network to which the source terminal belongs is written in VCI-F1, and the identification number of the source terminal in the sub-network is written in VCI-F2. Written.

(CLSF-O to IWU cell) VC
The identification number of the sub-network to which the destination terminal belongs is written in I-F1, and the identification number of the source network is written in VCI-F2. For example, the cell related to the datagram output from the terminal 63A is VCI-F.
The two fields may be VPI _636-1 or the like.

(Terminal to CLSF-O Cell-Method 2
The same as the above), the identification number of the sub-network to which the destination terminal belongs is written to VCI-F1, and the identification number of the source terminal within the sub-network is written to VCI-F2.

First, the transfer of a datagram from the terminal 63A to the terminal 63C will be described. The terminal 63A is CLSF-
Transfer the following cells to O63M. VPI-F is C
VP which is the access address of LSF-O63M
I _63M and VCI-F1 are set to the identification number of the network 631 (for example, VPI _63L which is the access address of CLSF-I _63L can be used), and VCI-F2 is set to the VPI _63A which is the access address of the terminal 63A.

The CLSF-O 63M transfers the following cells to the IWU 636 when there is no other datagram transfer to the sub-network 631. VP
IF is VP which is the access address of IWU636.
Set to I _636-2 . The VCI-F1 can copy the information of the reception cell as it is. VCI-F1
Is an identification number of the network 631 (for example, CLSF-I
It is also possible to use VPI _63L which is an access address of _63L ). The VCI-F2 is, for example, a VPI that is an identification number expressing the subnetwork 632.
_636-1 (access address of _IWU 636). VCI-F2 may be an identifier for identifying its own subnetwork. CLSF-
In O63M, the cells are sequentially IWU pipelined without reassembling the datagram.
636.

The VCI of the cell received by the IWU 636 is analyzed and the corresponding VPI-F and VCI-F2 are analyzed. For example, VCI-F1 with CLSF-I63L
In the embodiment in which the access address VPI _63L is written, the VPI-F of the cell to be output can be realized by copying the VPI _63L which is the VCI-F1 information of the received cell. VPI _636-1, which is the access address for the network 631 of the _{IWU 636,} is written in the VCI-F1. VCI-F2 can be set transparently. That is, for example, VCI-F1 of a cell transferred from CLSF-O63M
In the embodiment in which the access address VPI _63L of CLSF-I _63L is written in (1), VCI-F1 of the receiving cell is copied to VPI-F of the sending cell, and (2)
Cell relaying is realized by the procedure of copying the VCI-F2 of the receiving cell to the VCI-F2 of the sending cell, and writing the _{VW 636-1} , which is the IWU access address, in the VCI-F1 of the sending cell. To be done.

The datagram arriving at CLSF-I63L is once reassembled and the ATM connection is terminated. CLSF-I63L analyzes the address information of the upper layer, and the destination of the datagram is the terminal 63C.
Recognize that. Therefore, CLSF-I63L uses VP whose VPI-F is the access address of the terminal 63C.
_Create a cell that is I _63C and forward the datagram to terminal 63C. The terminal 63C can uniquely identify the datagram to which the cell belongs from the VCI-F1 and VCI-F2 (the datagram can be reassembled).

Next, the data from the terminal 63A to the public network 635 is transferred.
The transfer of the datagram will be described. The terminal 63A is CLSF
-Transfer the following cells to O63M. VPI-F
VPI which is the access address of CLSF-O63M
_63M, VCI-F1 is an identification number of the public network 635 (for example,
VPI which is the access address of IWU639₆₃₉For
VCI-F2 can access the terminal 63A.
VPI which is address _63ASet to.

CLSF-O63M is an IW when the datagram transfer to the public network 635 is not being performed.
The following cells are transferred to U636. VPI-F is
It is set in VPI _636-2 which is the access address of _{IWU 636} . The VCI-F1 can copy the information of the reception cell as it is. VCI-F1 is public network 6
35 identification number (for example, VPI ₆₃₉ which is an access address of IWU ₆₃₉ can be used). The VCI-F2 may be VPI _636-1 (access address of _IWU 636) which is an identification number expressing the sub-network 632. VCI-F2 may be an identifier for identifying its own subnetwork. At this time, the cells can be sequentially transferred to the IWU 636 in a pipeline without once reassembling the datagram in the CLSF-O63M.

The VCI of the cell received by the IWU 636 is analyzed and the corresponding VPI-F and VCI-F2 are analyzed. For example, in the embodiment in which the access address VPI ₆₃₉ of the IWU ₆₃₉ is written in the VCI-F1, the VPI-F of the cell to be output can be obtained by copying the VPI ₆₃₉ which is the VCI-F1 information of the received cell. realizable. The VCI-F1 has a VP which is an access address for the network 631 of the IWU 636.
I _636-1 is written. VCI-F2 can be set transparently. That is, for example, C
IW to VCI-F1 of the cell transferred from LSF63M
In the case of the embodiment in which the access address VPI _{639 of} U639 is written, (1) VCI-F1 of the receiving cell
To the VPI-F of the sending cell, and (2) V of the receiving cell
Copy CI-F2 to VCI-F2 of the sending cell, and (3)
The cell relaying is realized by the procedure of writing the IWU access address VPI _636-1 in the VCI-F1 of the transmission cell.

The IWU 639 writes the VCI / VPI assigned to the ATM connection 696 defined in the public network 635 from the VCI information of the received cell, and transfers the cell to the public network 635.

Finally, the transfer of the datagram from the terminal 63A to the terminal 63B will be described. The terminal 63A is CLSF
-Transfer the following cells to O63M. VPI-F is VPI which is the access address of CLSF-O63M.
_63M , VCI-F1 is an identification number of the network 633 (for example, VPI which is an access address of IWU637).
_{63 7-1} can also be used), VCI-F2 is terminal 63
Set to VPI _63A which is the access address of A.

The CLSF-O63M transfers the following cells to the IWU 636 when no other datagram is transferred to the sub-network 633. VP
IF is VP which is the access address of IWU636.
Set to I _636-2 . The VCI-F1 can copy the information of the reception cell as it is. VCI-F1
Is an identification number of the network 633 (for example, IWU637
It is also possible to use VPI _637-1 which is the access address of the above). VCI-F2 is an identification number expressing the sub-network 632, which is VPI _636-1 (IW
U636 access address). V
CI-F2 may be an identifier for identifying its own subnetwork. At this time, CLSF-O63
In M, the cells are sequentially pipelined by IWU 636 without once reassembling the datagram.
Can be transferred to.

The VCI of the cell received by the IWU 636 is
Parsed and the corresponding VPI-F and VCI-F2 are solved
Is analyzed. For example, the IWU637 access to VCI-F1
Set address VPI_637-1In which is written
, The VPI-F of the output cell is the received cell
VPI which is VCI-F1 information of_637-1Can be copied
It can be realized with. VCI-F1 is a network of IWU636.
VP which is an access address for the network 631
I_636-1Is written. VCI-F2 is a transp
Can be set to arent. That is, for example, C
To the VCI-F1 of the cell transferred from LSF-O63M
Access address VPI of IWU637 _637-1Is written
In the rare embodiment, (1) VCI of the receiving cell
-F1 is copied to the VPI-F of the sending cell, and (2) the receiving cell
Copy VCI-F2 of the cell to VCI-F2 of the sending cell
Then, (3) IWU access is made to the VCI-F1 of the sending cell.
VPI which is address_636-1To the procedure of writing
More cell relaying is realized.

Next, the V of the cell received by the IWU 637 is received.
The CI is analyzed and the corresponding VPI-F, VCI-F1 and VCI-F2 are analyzed. IWU637 to CL
The VCI field of the cell transferred to SF-I63J can transparently set the VCI field information of the received cell. That is, VC
I-F1 = VPI _637-1 , VCI-F2 = VPI _636-1
Can be Note that VPI-F is CLSF-
VPI _63J which is the access address of _{I63J is} set.

The datagram arriving at CLSF-I63J is once cell-reassembled and the ATM connection is terminated. CLSF-I63J analyzes the address information of the upper layer, and the destination of the datagram is the terminal 63B.
Recognize that. CLSF-I63J is VPI
-F is the VPI _{63 B} which is the access address of the terminal _{63 B}
A cell such that
Transfer to. It should be noted that the terminal 63B has VCI-F1 and VCI
-The datagram to which the cell belongs can be uniquely identified from F2 (the datagram can be reassembled).

(Sixth Embodiment) Next, an embodiment relating to a network configuration of a horizontal topology will be described. FIG. 69 shows the system configuration of this embodiment. As shown in the figure, a plurality of sub-networks 701 to 706
Is internetworking using IWU. The IWU can realize the relaying of ATM cells without terminating the ATM connection. That is, it has a function of converting the VCI / VPI of the received cell into the VCI / VPI assigned to the corresponding ATM connection in the adjacent network.

The connection line between the sub-networks 701 to 706 may be a connection line on campus or a private line / switch line of the public network. Further, although public networks 707 and 708 are shown in the figure, this indicates that it is possible to access terminals and networks other than the network defined through the public network. That is, for example, when communicating with a terminal connected to a general public network, the communication is performed through the public networks 707 and 708.

Each of the sub-networks 701 to 706 has a CLSF, and can handle cells related to connectionless communication. CL
Specific embodiments of the setting and operation of SF and the connectionless communication between terminals will be described later.

There is no particular limitation on the network distance (an index of how many relay points (sub-networks) are required to connect arbitrary points within the network). In the two-layer network described in the previous embodiment,
The network topology is such that the target sub-network can be reached via at most one relay sub-network. However, in the network handled here, there is basically no restriction on the distance of this network.

Further, in the following embodiments, the method of constructing the ATM connection for realizing the address resolution is not particularly mentioned. The method of realizing address resolution is basically the same as the method described in the above embodiment. That is, a method of analyzing the address information of the network (an image as shown in FIG. 49) in which each address resolution server is in an equal position,
This is a method in which the address resolution server has a logical hierarchical structure (an image as shown in FIG. 50) and manages and analyzes the address information. Also, the ATM connection set between the address resolution servers has any configuration from the full mesh configuration (configuration as shown in FIG. 59) to the minimum spanning tree configuration (configuration as shown in FIG. 58). It is possible to

(Embodiment 6-1) A case of application to a general ATM network.

The ATM connection in this embodiment is as follows. To transfer a datagram from a terminal connected to each sub-network to a terminal connected to an arbitrary sub-network, an ATM connection is set up from each IWU to CLSFs existing in all sub-networks. That is, from IWU to CL
The ATM connection (one-way ATM connection) to the SF is set in a full mesh form. In addition, ATM
IWU (relay IWU) existing on the path of the connection
Then, rewriting the ATM header information (at least VCI
/ VPI conversion) is performed and cell relaying is performed by ATM.
Performed as a layer job. That is, in principle, the ATM connection is not terminated when passing through the IWU.

The position where CLSF exists may be the position of IWU. Also, public network 707
IWU 70K and IWU 7 when a datagram is forwarded to the defined network from
At 0M, the received cell (to which the datagram belongs)
Is transferred to a server that terminates the datagram connection on the public network. Note that this server can also reside in the IWU. The server terminating the datagram transferred from the public network relays the datagram in the same procedure as the transfer of the datagram from the terminal in the defined network.

FIG. 80 shows the structure of an ATM connection when a datagram is transferred from the public network 707 to the terminal 70A. The datagram transferred from the public network 707 is once terminated by CLSF-P811 and then CLS.
It is transferred to the terminal 70A via F7011. The ATM connections are three connections 812, 813 and 814.

(Terminal Protocol) The procedure for the terminal according to the present embodiment to transmit the connectionless communication datagram to the destination terminal is as follows.

(1) The terminal issues an address resolution request (AR request). This is done either if the terminal is not capable of resolving the address on its own (eg, when there is no entry in the address resolution cache table), or always.

(2) The terminal is a VCI / VPI which is an ATM connection identifier prepared for accessing the corresponding terminal from the address resolution server.
Get information.

(3) The terminal completes the datagram transfer by inserting the cell into the network with the acquired VCI / VPI. The terminal does not need to perform the connection setting procedure defined in the ATM network when transferring the datagram.

(Routing) The final datagram delivery to each terminal in this embodiment is performed only for the network to which each CLSF belongs. That is, for example, the CLSF 7061 delivers the datagram to the terminals belonging to the network 706. Similarly, CLSF7
031 delivers the datagram only to the terminals in the network 703. If the network address of the datagram received by each CLSF does not exist in the address entry of that CLSF (or if the address of the received datagram is not an element of the network address space of that network), then the datagram is It is judged that the product was delivered by mistake. The actions for delivery of erroneous datagrams are not discussed here.

That is, each CLSF need only have the address information of the terminal of the network to which it belongs.
When the address of the received datagram exists in the own network, an appropriate ATM connection is selected and the datagram is relayed. FIG. 71 shows an example of protocol processing when a datagram is transferred from the terminal 70A to the terminal 70B. The ATM connection is once terminated by CLSF7061. That is, C
The OSI layer 3 protocol is terminated in LSF7061. CLSF7061 performs layer 3 protocol processing, and the data unit is transferred to the terminal 70B using the ATM connection. Thus, when transferring a datagram to a terminal other than its own subnetwork,
Datagram delivery is realized end-to-end with only one ATM connection termination.

Similarly, FIG. 73 shows from the terminal 70A to the public network 7
81 shows the case where the datagram is transferred to the terminal 08, and FIG. 81 shows the protocol configuration when the datagram is transferred from the public network 707 to the terminal 70A.

(Embodiment 6-1-1) Next, a more specific embodiment will be described.

(Regarding Datagram Transfer from Terminal 70A to Terminal 70B) FIG. 70 shows a block diagram of an ATM connection. The terminal 70A resolves the address of the terminal 70B when transferring the datagram (analyzes the access address information of the subnetwork to which the terminal 70B belongs). That is, the AR request message containing the address information of the terminal 70B is transferred to the address resolution server ARS. Upon receiving the AR request, the ARS performs address resolution, and then returns VCI / VPI information for transferring cells to the terminal 70B to the terminal 70A as an AR response.

ATM for transferring cells to terminal 70B
The terminal 70A, which has acquired the layer address (VCI / VPI) information, inputs the cell to which the VCI / VPI is added to the network. The cell is IWU70D with VCI / V
After PI conversion, the data is transferred to the IWU 70G.
Similarly, the cell is transferred to the CLSF 7061 via the IWU 70H and IWU 70J. C that received the cell
The LSF7061 analyzes the information of the address information (layer 3) included in the datagram, and transfers the cell to the terminal 70B. The cell transfer from the CLSF 7061 to the terminal 70B may be performed after the CLSF 7061 receives all the cells belonging to the datagram, or after the layer 3 address of the datagram is analyzed, the cells are relayed in a pipeline manner. May be.

(Regarding Datagram Transfer from Terminal 70A to Public Network 708) FIG. 72 shows a block diagram of an ATM connection. When transferring the datagram, the terminal 70A performs resolution of the address of the target terminal (analyzes access address information of the subnetwork to which the destination terminal belongs). That is, the AR request message containing the address information of the destination terminal is transferred to the address resolution server ARS. A who received the AR request
After the resolution of the address, the RS returns the VCI / VPI information for transferring the cell to the terminal to the terminal 70A as an AR response.

[0640] The terminal 7 which has acquired the ATM layer address (VCI / VPI) information for transferring the cell to the destination terminal.
0A turns on the cell to which the VCI / VPI is added in the network. The cell is IWU70D with VCI / VP
After the conversion of I is performed, it is transferred to the IWU 70E. Similarly, the cell is transferred to the public network 708 via the IWU 70M.

(Regarding Datagram Transfer from Public Network 707 to Terminal 70A) FIG. 80 shows a configuration diagram of an ATM connection. The source terminal exists in the public network 707, and the cell related to the connectionless communication from the public network 707 is CLSF-P811 via the IWU 70K.
Transferred to. The VCI / VPI conversion table of the IWU 70K is set so that when a cell having VCI / VPI assigned to a cell used for connectionless communication in the public network 707 arrives, the cell is transferred to the CLSF-P811. ing.

CLSF-P811 terminates the ATM connection once and analyzes the layer 3 address information of the datagram. The address information to be analyzed is CLSF-P81.
If it does not exist in the table in 1, an AR request is issued to ARS. A for transferring the cell to the terminal 70A
The CLSF-P811 which has acquired the TM layer address (VCI / VPI) information inputs the cell to which the VCI / VPI is added to the network. The cell is IWU70G
After the VCI / VPI conversion is performed in step 1, the data is transferred to the IWU 70D. In addition, cells are IWU 70D to CLSF
7011. CLSF70 receiving the cell
11 is address information of the datagram (layer 3)
Information is analyzed and the cell is transferred to the terminal 70A. In addition,
The cell transfer from the CLSF 7011 to the terminal 70A and the cell transfer from the CLSF-P811 to the IWU 70G may be performed after the CLSF7011 and CLSF-P811 have received all the cells belonging to the datagram, or the layer 3 address of the datagram may be set. After analysis, the cells may be relayed in a pipeline manner.

(Embodiment 6-2) An embodiment applied to a general ATM network will be described. In order to transfer a datagram from any terminal connected to each sub-network to a terminal connected to any sub-network, an ATM connection is set up from each CLSF to CLSFs existing in all sub-networks. There is. That is, the ATM connection between CLSFs is set to a full mesh. At the IWU (relay IWU) existing on the path of the ATM connection, the AT
Rewriting of M header information (at least VCI / VPI conversion) is performed, and cell relaying is performed as a task of the ATM layer. That is, in principle, the ATM connection is not terminated when passing through the IWU. In addition,
The position where the CLSF exists may be the IWU position.

When the datagram is transferred from the public networks 707 and 708 to the defined network, the received cell (to which the datagram belongs) in the IWU 70K and IWU 70M once terminates the datagram connection of the public network. Transferred to the server.
It should be noted that this server can also reside in the IWU. The server terminating the datagram transferred from the public network relays the datagram in the same procedure as the transfer of the datagram from the terminal in the defined network.

FIG. 82 shows the structure of an ATM connection when a datagram is transferred from the public network 707 to the terminal 70A. The datagram transferred from the public network 707 is once terminated by CLSF-P811 and then CLS.
It is transferred to the terminal 70A via F7031 and F7011.
The ATM connections are four connections 831, 832, 833 and 834.

(Regarding Terminal Protocol) When the terminal determines that the datagram is destined for the external sub-network, the terminal transfers the datagram to the CLSF. The CLSF is basically located in the same sub-network as the terminal, but may be in another sub-network such as an adjacent node. Note that an ATM connection has already been set up between the terminal and CLSF. Each terminal has the information (address mask, etc.) of the address space of the sub-network to which the terminal belongs,
It is possible to determine whether the destination terminal is within its own subnetwork or an external subnetwork.

In the case of the network configuration shown in FIG. 69, the following methods are available as datagram delivery methods.

(1) A star-shaped ATM connection is set between the CLSF and the terminal. When transferring a datagram, the terminal transfers cells to CLSF. CLSF handles all datagram delivery. That is, communication between terminals in the sub-network is once C
Via LSF.

(2) Communication between terminals in the sub-network is realized without CLSF, while communication with terminals in the external network is realized via CLSF.

(Regarding Routing) The final datagram is delivered to each terminal only for the network to which each CLSF belongs. That is, for example, CLSF7
061 delivers the datagram to the terminals belonging to the network 706. Similarly, the CLSF 7031 delivers the datagram only to the terminals in the network 703. If the network address of the datagram received by each CLSF does not exist in the address entry of that CLSF (or if the address of the received datagram is not an element of the network address space of that network), then the datagram is It is judged that the product was delivered by mistake. The actions for delivery of erroneous datagrams are not discussed here.

That is, each CLSF need only have the address information of the terminal of the network to which it belongs.
When the address of the received datagram exists in the own network, an appropriate ATM connection is selected and the datagram is relayed.

FIG. 74 shows the configuration of the connection when the datagram is transferred from the terminal 70A to the terminal 70B. The ATM connection is terminated with CLSF7011 and CLSF7061. That is, CLSF7
The OSI layer 3 protocol is terminated at 061 and CLSF7011. The layer 3 protocol processing is performed in the CLSF 7011, and the data unit is transferred to the IWU 70D using the ATM connection. CLSF7
At 061, the layer 3 protocol processing is performed, and the data unit is transferred to the terminal 70B using the ATM connection. Thus, when transferring a datagram to a terminal other than its own subnetwork, datagram delivery is realized end-to-end by terminating the ATM connection twice.

Similarly, FIG. 75 shows from the terminal 70A to the public network 7.
It shows a case where the datagram is transferred to 08.

(Embodiment 6-2-1) Next, a more specific embodiment will be described.

(Regarding Datagram Transfer from Terminal 70A to Terminal 70B) FIG. 74 shows a block diagram of an ATM connection. When the terminal 70A analyzes that the terminal 70B belongs to the external subnetwork when transferring the datagram to the terminal 70B, the CLSF 701
Transfer the datagram to 1. The CLSF 7011 analyzes the address information of the received datagram, and the terminal 70B
When it does not have ATM layer address information for transferring a datagram to (CLSF7061), AR
The address resolution request cell having the address information of the terminal 70B is transferred to S. Upon receiving the AR request, the ARS performs address resolution and then CL
V for transferring a cell to SF7061 (terminal 70B)
CLSF7011 with CI / VPI information as AR response
Return to.

ATM for transferring cells to terminal 70B
CL that acquired the layer address (VCI / VPI) information
SF7011 inputs the cell to which the VCI / VPI is added to the network. Cell is IWU70D and VC
After the I / VPI conversion, the data is transferred to the IWU 70G. Similarly, the cell is transferred to the CLSF 7061 via the IWU 70H and IWU 70J. Upon receiving the cell, the CLSF 7061 analyzes the information of the address information (layer 3) included in the datagram, and transfers the cell to the terminal 70B. The cells may be transferred from the CLSF 7061 to the terminal 70B after the CLSF 7061 has received all the cells belonging to the datagram, or after the layer 3 address of the datagram is analyzed, the cells are relayed in a pipeline manner. May be.

(Regarding Datagram Transfer from Terminal 70A to Public Network 708) FIG. 75 is a block diagram of an ATM connection. When transferring the datagram to the target terminal of the public network 708, the terminal 70A performs resolution of the address of the destination terminal (analyzes access address information of the subnetwork to which the destination terminal belongs). That is, when the terminal 70A cannot resolve the address information of the destination terminal, it transfers an AR request message containing the address information of the destination terminal to the address resolution server ARS. AR receiving AR request
After performing the address resolution, the S returns the access address information of CLSF7011 to the terminal 70A as the AR response of the VCI / VPI information for transferring the cell to the destination terminal. When analyzing that the destination is a terminal belonging to the external sub-network, the terminal 70A receives the VCI / VPI information or the VC obtained as a result of the analysis.
The I / VPI information is added to the cell to make the cell CLSF70.
Transfer to 11.

The CLSF 7011 analyzes the address information of the received datagram, and when it does not have the ATM layer address information for transferring the datagram to the destination terminal, the address resolution having the address information of the destination terminal is sent to the ARS. Transfer the request cell. Upon receiving the AR request, the ARS performs the address resolution and then the VCI / V for transferring the cell to the IWU 70M.
The PI information is returned to the CLSF 7011 as an AR response.

CLS that has acquired ATM layer address (VCI / VPI) information for transferring a cell to a destination terminal
In F7011, the cell to which the VCI / VPI is added is input to the network. The cell is VCI with IWU70D
After the / VPI conversion, it is transferred to the IWU 70E. Similarly, the cell is connected to the public network 7 via the IWU 70M.
08 is transferred.

(Regarding Datagram Transfer from Public Network 707 to Terminal 70A) FIG. 82 shows a block diagram of an ATM connection. The source terminal exists in the public network 707, and the cell related to the connectionless communication from the public network 707 is CLSF-P811 via the IWU 70K.
Transferred to. The VCI / VPI conversion table of the IWU 70K is set so that when a cell having VCI / VPI assigned to a cell used for connectionless communication in the public network 707 arrives, the cell is transferred to the CLSF-P811. ing.

CLSF-P811 terminates the ATM connection once and analyzes the layer 3 address information of the datagram. The address information to be analyzed is CLSF-P81.
If it does not exist in the table in 1, an AR request is issued to ARS. A for transferring the cell to the terminal 70A
TM layer address (VCI / VPI) information (cell to C
(VCI / VPI information for transfer to LSF7031)
CLSF-P811 which acquired the
The cell to which is added is input to the network. CLSF7
031 analyzes the address information of the received datagram, and when it does not have the ATM layer address information for transferring the datagram to the terminal 70A (CLSF7011), the address resolution that has the address information of the terminal 70A to the ARS. Transfer the request cell. Upon receiving the AR request, the ARS performs the address resolution, and then uses the VCI / VPI information for transferring the cell to the CLSF 7011 (terminal 70A) as the CL response in the CL.
Return to SF7031.

ATM for transferring cells to terminal 70A
CL that acquired the layer address (VCI / VPI) information
SF7031 inputs the cell to which the VCI / VPI is added to the network.

The cell is transferred to IWU 70D after VCI / VPI conversion by IWU 70G. Further, the cell is transferred from the IWU 70D to the CLSF 7011. Upon receiving the cell, the CLSF 7011 analyzes the address information (layer 3) of the datagram,
The cell is transferred to the terminal 70A. Note that CLSF7011
Transfer of Cell to Terminal 70A and CLSF-P81
Cell transfer from 1 to CLSF7031 and further CLS
Transfer of cells from F7031 to IWU70G is performed by CLS.
F7011, CLSF7031 and CLSF-P81
1 may receive all the cells belonging to the datagram, or may analyze the layer 3 address of the datagram and then relay the cells in a pipeline manner.

(Embodiment 6-3) Regarding the case of application to an ATM network of VPI routing.

(ATM Connection) Each sub-network has a sub-network identification number of 8 bits. In the defined network, the sub-network can be uniquely identified by this identification number. The identification number of the sub-network is described as Net _i . For example, the identification number of the subnetwork 702 is Ne.
t ₇₀₂ . All IWUs have acquired an access address (VPI) for connectionless communication in both. In addition, CLSF on the receiving side (CLSF that handles cells arriving from IWU, which can be configured differently from CLSF that handles cells for connectionless communication that come from terminals in its own network) is also connectionless communication Has acquired an access address (VPI).

The VCI / VPI field coding is as follows.

(1) CLS of the own network from the transmitting terminal
Cell to F (1-1) VPI-F; CLSF access address (1-2) VCI-F1; Destination network address Ne
t _i or arbitrary (1-3) VCI-F2; access address of own terminal (2) cell between CLSF (2-1) VPI-F; access address of next access element (IWU or destination CLSF) (2 -2) VCI-F1; Destination network address Ne
t _destnation (2-3) VCI-F1; network address to which the sending terminal belongs Net _source (3) Cell (3-1) VPI-F from CLSF of the network of the destination terminal to the destination terminal; access address of the destination terminal (3 -2) VCI-F1; can be set to any value (3-3) VCI-F2; can be set to any value. It can be set to any value because the cell received by the destination terminal is certainly other It means that any value can be set as long as it is set so that it can be distinguished from the cell arriving from any access point.

(Subnetwork in which the transmitting terminal exists)
First, cell VCI / VPI from transmission terminal to CLSF
Explain the coding of fields. VPI-F is
It is an access address of CLSF. VCI-F2 is
It is defined as the access address of the sending terminal. VCI-F1
Coding is performed when the sending terminal performs resolution of the subnetwork to which the destination terminal belongs, and
There are two cases when doing in.

(A) The sending terminal resolves; the sending terminal resolves the address of the destination sub-network and the identification number Net of the sub-network.
It writes the _{destin ation} to the VCI-F1.

(B) CLSF resolves; since CLSF performs resolution of the destination network, VCI-F1 can be set to an arbitrary value in this case.

Next, the VC of the cell from CLSF to IWU
The I / VPI coding will be described. VPI-F
Is the access address of the IWU. VCI-F1
Is set to the identification number of the destination network (Net
_destination ). The VCI-F2 is set to the network identification number of the transmission terminal (Net _source ). VCI-
The setting method of F1 is as follows: when the sending terminal performs resolution of the subnetwork to which the destination terminal belongs,
There are two cases when doing in.

(A) The sending terminal makes a resolution; the sending terminal's identification number Net _destination written in VCI-F1 is copied to VCI-F.
Write to 1.

(B) CLSF resolves; writes the resolved value.

When transferring cells from CLSF to IWU, interleaving between cells belonging to different datagrams to the same destination network is not permitted (cell interleaving is possible for datagrams to different destination networks). That is, a series of cells belonging to one datagram are continuously transferred. That is, the cell is CLed from each transmitting terminal at an arbitrary timing.
Although it is possible to transfer to the SF, cells are transferred from the CLSF to the IWU for each datagram. In the IWU, the VPI-F is based on the Net _destination written in the VCI-F1 of the received cell.
Determine the value of. That is, the IWU table contains Ne.
A table of VPI-F corresponding to t _destination is set.

The VCI-F1 and VCI-F2 are transferred transparently. Also, Net
A routing protocol for determining VPI-F from the _destination, that is, a subnetwork to be relayed is separately executed, and a table of each IWU is set.

(Inter-IWU) According to the IWU table,
The cell is relayed. That is, the VC of the receiving cell
VPI-F for relaying a cell to the next IWU is written based on the Net _{destination of} I-F1.

(Subnetwork to which the destination terminal belongs) The IWU to which the destination terminal belongs is the VCI-F1 of the received cell.
It can be seen that the received cell is destined for its own subnetwork. In the VPI-F setting table set in the IWU, VPI numbers for transferring cells to the CLSF are set. IWU is the VPI
Is set to VPI-F and the cell is transferred to CLSF.
At this time, VCI-F1 and VCI-F2 are transferred transparently.

The received CLSF reassembles the datagram based on the VCI information. At this time, cells to which different datagrams belong are interleaved and CLSF
However, the information of the VCI field can be used to successfully reconstruct each datagram even when the cells are interleaved. The destination address (layer 3 address) of the received datagram is analyzed and the datagram is transferred to the appropriate terminal.

VP of cell transferred from CLSF to terminal
IF is an access address of the terminal. Next, VC
For the I field, the VCI defined by the cell received by the terminal for the cell for connectionless communication is used (it is also possible that multiple VCIs are defined). This VCI is usually preset between CLSF and the terminal. When there are multiple VCIs for connectionless, it is possible to transfer cells from CLSF to terminals in a pipeline manner (cells to which different datagrams belong can be interleaved) as long as the identification numbers do not collide. it can.

For example, VCI-F1 and VCI-F2
If the VCI field format of is defined in the communication from the CLSF to the terminal, that is, when the VCI field format of the communication in the sub-network is unified in this way, the VCI-F2 of the cell received by the CLSF is Set as it is in VCI-F2 of the cell to be transferred from CLSF to the terminal, and set as VCI-F1 of the cell from CLSF to the terminal as a value that can recognize that the receiving cell is a cell involved in connectionless communication. For example, the entire datagram can be pipelined.

(Specific Example) First, the transfer of a datagram from the terminal 70A to the terminal 70B will be described with reference to FIGS. It is made up of three ATM connections. (1) Connection 791 from terminal 70A to CLSF7011, (2) CLSF7011 to CLSF706
Connections 1 to 792-796, (3) CLSF70
The connection 797 is from 61 to the terminal 70B.

The terminal 70A transfers a cell having VPI-F = VPI ₇₀₁₁ . The VCI-F2 is the terminal 70A.
VPI _70A , which is the access address of Also, V
When the terminal 70A itself resolves the address information (Net ₇₀₆ ) of the sub-network to which the destination terminal belongs, the CI-F1 sets this value Net ₇₀₆ to VCI-F.
Written to 1. When the CLSF 7011 performs resolution, the VCI-F1 can be set arbitrarily.

CLSF 7011 transfers the following cell to IWU 70D. VPI-F is an access address of IWU _70D , VPI _70D-1 , VCI-F1 is an identification address of network 706, Net ₇₀₆ , V
CI-F2 is Net ₇₀₁ which is an identification address of the network 701. When VCI-F1 copies the value of the received cell as it is (the terminal analyzes Net ₇₀₆ )
In some cases, CLSF 7011 analyzes and sets Net ₇₀₆ .

VCI-of the cell received by the IWU 70D
F1 is analyzed and the corresponding VPI-F is analyzed. That is, the VPI capable of transferring the cell toward the IWU which is transferred to the network 706 is analyzed (set in the table). VCI-F1 and V
CI-F2 copies the field of the received cell as it is. That is, VCI-F1 is written with Net _706, which is the network identification number of the sub-network 706 to which the destination terminal 70B belongs. Similarly, hereafter
The WU selects an appropriate VPI based on the information of Net ₇₀₆ which is the information written in the VCI-F1 of the received cell,
The cell is transferred to IWU 70J.

The cell arriving at IWU 70J is VCI-
It recognizes from the F1 information that the cell has been transferred to the target network, and transfers the cell to the CLSF7061. CL
The datagram arriving at SF7061 is once subjected to cell reassembly, and the ATM connection is terminated. C
LSF7061 analyzes upper layer address information,
It recognizes that the destination of the datagram is the terminal 70B. Then, the CLSF 7061 creates a cell and transfers the datagram to the terminal 70B. Regarding the transfer of the cell to the terminal 70B, it is possible to transfer the cell in a pipeline from the reception of the cell of the CLSF 7061 when the connectionless communication channel to the terminal 70B is sufficient.

Transfer of a datagram from the terminal 70A to the public network 708 will be described below with reference to FIG.
The terminal 70A transfers a cell having VPI-F = VPI ₇₀₁₁ . The VCI-F2 is the VPI _70A which is the access address of the terminal 70A. Also, when the terminal 70A itself resolves the address information (Net ₇₀₈ ) of the sub-network to which the destination terminal belongs, this value Net ₇₀₈ is written in the VCI-F1 in the VCI-F1. When the CLSF 7011 performs resolution, the VCI-F1 can be set arbitrarily.

The CLSF 7011 transfers the following cell to the IWU 70D. VPI-F is an access address of IWU _70D , VPI _70D-1 , VCI-F1 is an identification address of public network 708, Net ₇₀₈ , VCI-.
F2 is a network 701 identification address Net
It is ₇₀₁ . When VCI-F1 copies the value of the received cell as it is (the terminal analyzes Net ₇₀₆ ), CCI-F1
There is a case where the LSF 7011 analyzes and sets Net ₇₀₈ . VCI-F1 of cell received by IWU 70D
Is analyzed and the corresponding VPI-F is analyzed. That is, the VPI capable of transferring the cell toward the IWU which is transferred to the network 708 is analyzed (set in the table). VCI-F1 and VCI
-F2 copies the received cell field as is. That is, VCI-F1 is the network identification number N of the sub-network 708 to which the destination terminal belongs.
et ₇₀₈ is written. Similarly thereafter, in the IWU, the Ne written in the VCI-F1 of the received cell is Ne.
An appropriate VPI is selected based on the information of t ₇₀₈ , and the cell is I
Transferred to WU70M. The IWU 70M determines the AT defined in the public network 708 from the VCI information of the received cell.
The VCI / VPI assigned to the M connection is written, and the cell is transferred to the public network 708.

(Seventh Embodiment) Next, an embodiment relating to connectionless communication in a large-scale networking configuration will be described.

When the number of defined sub-networks is very large, it can be dealt with by internetworking the above-mentioned networks. That is, this is a method of viewing adjacent networks (networks defined as an aggregate of a plurality of sub-networks described above) as one sub-network.

FIG. 84 shows the structure of the network as viewed from the network 861. The actual network configuration is shown in FIG. In this way, the three networks 862 to 864 look like one sub-network 851 when viewed from the network 861. Network 8
The address space of the network 851 viewed from 61 can be seen as a space combining the networks 862 to 864.

In FIG. 86, the following network constituent elements involved in the datagram transfer are shown in a simplified manner among the network constituent elements. In the following, the above-mentioned 2
An example of datagram transfer from the terminal 87A to the terminal 87B and datagram transfer from the terminal 87A to the terminal 87C in one system configuration will be described.

(Embodiment 7-1) This embodiment is an example in which a terminal can directly transfer a cell to an external network. In other words, this is a method that does not use the CLSF in the own network when transferring the datagram to the terminal in the external network.

(Regarding Datagram Transfer from Terminal 87A to Terminal 87B) FIG. 87 shows the structure of the ATM connection. This is four ATM connections 881-8
84 is configured. The terminal 87A resolves the network layer address of the terminal 87B,
V for resolving that B belongs to network 851 and at the same time transferring cells to CLSF 871
Obtain CI / VPI information. The details are as described above.

The datagram is once terminated by the CLSF 871 (the ATM connection is also terminated), and the layer 3
Protocol processing is performed. The CLSF 871 analyzes the network layer address, analyzes that the terminal 87B exists in the network 863, and further
VCI / VPI information for transferring cells to LSF 872 is obtained. Datagram is ATM connection 8
82 to the CLSF 872.

The datagram is terminated by the CLSF 872 (the ATM connection is also terminated), and the layer 3 protocol processing is performed. The analysis of the network layer address is performed by the CLSF 872, and the VCI / VPI information for transferring the cell to the CLSF 873 is acquired.
Datagram is CL using ATM connection 883
Transferred to SF873.

CLSF873 that received the datagram
Analyzes the access address of the terminal 87B by analyzing the network layer address of the datagram. The cell to which the appropriate VCI / VPI is added is the terminal 8
7B is transferred.

In this way, the ATM connection is terminated three times and the protocol processing is performed in the network layer, and the datagram is transferred from the terminal 87A to the terminal 87B.

(Regarding Datagram Transfer from Terminal 87A to Terminal 87C) FIG. 88 shows the configuration of the ATM connection. This is two ATM connections 891,8
It is composed of 92. The terminal 87A resolves the network layer address of the terminal 87C and
7C resolves to belong to the network 851, and at the same time acquires VCI / VPI information for transferring cells to the CLSF 871. The details are as described above.

The datagram is once terminated by CLSF 871 (the ATM connection is also terminated), and is then layer 3
Protocol processing is performed. The analysis of the network layer address is performed by the CLSF 871, the presence of the terminal 87C in the network 864 is analyzed, and further,
VCI / V for transferring cells to network 864
PI information is acquired. Here, the network 862
Cell transfer to the IWU between the network and the network 864.

In this way, one ATM connection termination and protocol processing in the network layer are performed, and the datagram is transferred from the terminal 87A to the network 864 in which the terminal 87C exists. CLSF
The transfer destination of the datagram from 871 may be the CLSF in the public network 864. In this case, A more than once
Termination of the TM connection and protocol processing at the network layer level are performed.

(Embodiment 7-2) This embodiment is an example when the terminal cannot directly transfer the cell to the external network. In other words, when forwarding a datagram to a terminal on an external network, the C
This is a method of using LSF once.

(Regarding Datagram Transfer from Terminal 87A to Terminal 87B) FIG. 89 shows the structure of an ATM connection. This is 5 ATM connections 901-9
It consists of 05. The terminal 87A resolves the network layer address of the terminal 87B,
7A resolves that it belongs to network 851 (or analyzes sending cells to CLSF 874) and at the same time obtains VCI / VPI information for transferring cells to CLSF 874. The details are as described above.

The CLSF 874 receiving the cell is (1)
It recognizes that the cell needs to be transferred to the network 862 (CLSF 871) by analyzing the network layer address of the datagram or (2) using the result of the analysis by the terminal 87A. At the same time, the VCI / VPI information for transferring the cell to the CLSF 871 is acquired, and the datagram is transferred to the CLSF 871.

The datagram is once terminated by the CLSF 871 (the ATM connection is also terminated), and the layer 3
Protocol processing is performed. The CLSF 871 analyzes the network layer address, analyzes that the terminal 87B exists in the network 863, and further
VCI / VPI information for transferring cells to LSF 872 is obtained. Datagram is ATM connection 9
03 is used to transfer to the CLSF 872.

The datagram is terminated by CLSF872 (the ATM connection is also terminated), and the layer 3 protocol processing is performed. The analysis of the network layer address is performed by the CLSF 872, and the VCI / VPI information for transferring the cell to the CLSF 873 is acquired.
Datagram is CL using ATM connection 904
Transferred to SF873. C receiving the datagram
The LSF 873 analyzes the network layer address of the datagram and analyzes the access address of the terminal 87B. The cell to which the appropriate VCI / VPI is added is transferred to the terminal 87B.

In this way, the ATM connection is terminated four times and the protocol processing (3
The datagram is transmitted to the terminal 87A.
Is transferred to the terminal 87B.

(Regarding Datagram Transfer from Terminal 87A to Terminal 87C) FIG. 90 shows the structure of the ATM connection. This is three ATM connections 911-9
It consists of 13. The terminal 87A resolves the network layer address of the terminal 87C and
7C resolves to belong to network 851 (or analyzes sending cell to CLSF 874) and at the same time acquires VCI / VPI information for transferring cell to CLSF 874. The details are as described above.

The CLSF 874 receiving the cell receives (1)
It recognizes that the cell needs to be transferred to the network 862 (CLSF 871) by analyzing the network layer address of the datagram or (2) using the result of the analysis by the terminal 87A. At the same time, the VCI / VPI information for transferring the cell to the CLSF 871 is acquired, and the datagram is transferred to the CLSF 871.

The datagram is once terminated by CLSF871 (the ATM connection is also terminated), and the layer 3
Protocol processing is performed. The CLSF 871 analyzes the network layer address, analyzes that the terminal 87C exists in the network 864, and further VCI / VP for transferring a cell to the network 864.
I information is acquired. Here, cells are transferred to the IWU between the network 862 and the network 864.

Thus, two ATM connection terminations and network layer protocol processing (1
The datagram is transmitted to the terminal 87A.
To the network 864 in which the terminal 87C exists. The transfer destination of the datagram from the CLSF 871 may be the CLSF in the public network 864. In this case, ATM connection termination and protocol processing at the network layer level are performed twice or more.

[0711]

As described above, according to the present invention, A
It is possible to realize communication between ATM networks without impairing the features of the high speed, large capacity and connection oriented property of the TM communication system.

Also, according to the present invention, datagram delivery using the ATM network can be efficiently performed.

Furthermore, according to the present invention, connectionless communication (datagram delivery) between terminals connected to the ATM network can be performed at high speed.

[Brief description of drawings]

FIG. 1 is a diagram showing an ATM network according to a first embodiment.

FIG. 2 is a diagram showing an internal structure of a network connection device 13.

FIG. 3 is a diagram showing a drop table.

FIG. 4 is a diagram showing an internal configuration of an ATM-LAN.

FIG. 5 is a terminal in the ATM-LAN and a C in the inter-network connection device.
The figure which shows the connection state of the ATM connection between LSF processing parts.

[Fig. 6] Fig. 5 shows a CLS separately provided in the ATM-LAN.
Diagram showing the case where the F processing unit is prepared

FIG. 7 is a diagram showing a format of a broadcast cell.

FIG. 8 is a diagram showing a format of a broadcast cell when ARP is performed.

FIG. 9 is a diagram showing a connection state of an ATM connection between a terminal in an ATM-LAN and a call processing unit in an inter-network connecting device.

FIG. 10 is a diagram showing another example of the connection state of the ATM connection between the terminal in the ATM-LAN and the call processing unit in the inter-network connecting device.

FIG. 11 is a diagram showing an example in which a call processing unit does not exist in the inter-network connection device.

FIG. 12 is a diagram showing various forms of broadcasting.

FIG. 13 is a diagram showing an ATM network according to a second embodiment.

FIG. 14 is a diagram showing an internal structure of a network connection device 134.

FIG. 15 is a diagram showing an internal structure of an ATM-LAN.

FIG. 16 is a diagram showing a connection state of an ATM connection between a terminal in the ATM-LAN and a CLSF processing unit in the inter-network connecting device.

FIG. 17 is a diagram showing a connection state of an ATM connection between a terminal in the ATM-LAN and a call processing unit in the inter-network connection device.

FIG. 18 is a diagram showing another example of the connection state of the ATM connection between the terminal in the ATM-LAN and the call processing unit in the inter-network connection device.

FIG. 19 is a diagram showing an example in which a call processing unit does not exist in the inter-network connecting device.

FIG. 20 is a diagram showing a large-scale ATM network.

FIG. 21: ATM- in a large-scale ATM network
Diagram showing the internal structure of the LAN

FIG. 22 is a diagram showing an example of VPI value allocation in ATM-LAN.

FIG. 23 is a diagram showing an example of an ARP cell format.

FIG. 24 is a diagram showing an example of a network layer protocol identification method.

FIG. 25 is a diagram showing an example of a cell format when an ARP response using a broadcast channel is performed using an end-to-end ATM connection.

FIG. 26 is a diagram showing an example of an ARP flow.

FIG. 27 is a diagram showing a correspondence table of network layer addresses and ATM addresses (VPI values) in the ARP server.

FIG. 28 is a CLSF processing unit and ATM-L in the inter-network connection device
ATM connection connection state between terminals in AN and AT
ATM between the CLSF processing units in the M backbone network
Diagram showing an example of the connection status

FIG. 29 is a diagram showing an example (phase 1) of a CLSF processing unit placement method at the time of initial introduction.

FIG. 30 is a diagram showing a header value added to an ATM cell of a datagram sent from the inter-network connecting device to the CLSF processing unit.

FIG. 31 is a diagram showing a flow of header conversion.

FIG. 32 is a diagram showing an example (phase 2) of a CLSF processing unit arrangement method when a CLSF processing unit is added;

FIG. 33 is a diagram showing a table in the ARP server.

FIG. 34 is a diagram showing a connection state of an ATM connection between a call processing unit in the inter-network connecting device and an ATM-LAN terminal and a connection state of an ATM connection between the call processing units in the ATM backbone network.

FIG. 35 is a diagram showing another example of the call processing method in the large-scale network.

FIG. 36 is a diagram showing an example of an ATM board.

FIG. 37 is a diagram showing an example of an ARP cell in VP routing.

FIG. 38 is a diagram showing an example of the internal configuration of the IWU 13.

FIG. 39 is a diagram showing another example of the internal configuration of the IWU 13.

FIG. 40 shows a datagram communication system within a sub-network.

FIG. 41 is a diagram showing a datagram communication sequence.

FIG. 42 is a flowchart showing a datagram transmission procedure.

FIG. 43 shows a datagram communication system within a sub-network.

FIG. 44 is a diagram showing a datagram communication sequence.

FIG. 45 is a diagram showing VPI routing.

FIG. 46 is a diagram showing a two-layer network.

FIG. 47 is a diagram showing a connection between ARs.

FIG. 48 is a diagram showing an ATM connection required for datagram communication.

FIG. 49 shows an address space view from ARS481.

FIG. 50 shows an address space view from ARS482.

FIG. 51 is a diagram showing an ATM connection between ARSs.

FIG. 52 shows an address space view from ARS482.

FIG. 53 shows an address space view from ARS481.

FIG. 54 is a diagram showing a VCI / VPI conversion table in the IWU476.

FIG. 55 is a diagram showing datagram transfer protocol processing.

FIG. 56 is a diagram showing a datagram transfer from the terminal 47A to the terminal 47D.

FIG. 57 is a diagram showing datagram transfer from the terminal 47A to the terminal 47D.

FIG. 58 is a diagram showing an example of a VCI / VPI allocation method between ARSs.

FIG. 59 is a diagram showing another example of the VCI / VPI allocation method between ARSs.

FIG. 60 is a diagram showing another example of the VCI / VPI allocation method between ARSs.

FIG. 61 is a diagram showing a VCI / VPI allocation method for datagram transfer.

FIG. 62 is a diagram showing a network configuration.

FIG. 63 is a diagram showing an ATM connection required for datagram transfer.

FIG. 64 is a diagram showing ATM connection between ARSs.

FIG. 65 is a diagram showing ATM connection between ARSs.

FIG. 66 is a diagram showing an ATM connection required for datagram transfer.

FIG. 67 is a diagram showing datagram transfer protocol processing.

FIG. 68 is a diagram showing an example of datagram transfer.

FIG. 69 is a diagram showing a network configuration.

FIG. 70 is a diagram showing an example of datagram communication between terminals 70A → 70B.

71 is a diagram showing protocol processing. FIG.

FIG. 72 is a diagram showing an example of datagram communication between terminals 70A → 70B.

FIG. 73 is a diagram showing an example of datagram communication from the terminal 70A to the public network 708.

FIG. 74 is a diagram showing an example of datagram communication between terminals 70A → 70B.

FIG. 75 is a diagram showing an example of datagram communication from the terminal 70A to the public network 708.

FIG. 76 is a diagram showing an ATM connection of the terminals 70A → 70B.

77 is a diagram showing an example of datagram communication from the terminal 70A to the public network 708. FIG.

FIG. 78 is a diagram showing an ATM connection of the terminals 70A → 70B.

FIG. 79 is a diagram showing an example of datagram communication from the terminal 70A to the public network 708.

FIG. 80 is a diagram showing an example of datagram communication from the public network 708 to the terminal 70A.

FIG. 81 is a diagram showing protocol processing of the public network 708 → the terminal 70A.

FIG. 82 is a diagram showing an example of datagram communication from the public network 708 to the terminal 70A.

FIG. 83 is a diagram showing protocol processing of the public network 708 → terminal 70A.

FIG. 84 is a diagram showing an image from the network 861.

FIG. 85 is a diagram showing a network configuration.

FIG. 86 is a diagram showing a network configuration.

FIG. 87 is a diagram showing an example of datagram communication from terminal 87A to 87B.

FIG. 88 is a diagram showing an example of datagram communication between terminals 87A → 87C.

FIG. 89 is a diagram showing an example of datagram communication from terminal 87A to 87B.

FIG. 90 is a diagram showing a datagram communication example of the terminals 87A → 87C.

[Explanation of symbols]

11, 12 ... ATM-LAN 13 ... IWU (inter-network connection device) 21 ... Add / drop processing unit 22 ... Multiplexer / demultiplexer 23 ... CLSF processing unit (connectionless service function processing unit) 24 ... Call processing unit 25 ... IWU Management unit 26 ... Header conversion processing units 41-44 ... Switch nodes 4A-4G ... Terminals 91, 92 ... Call processing units 101, 102 ... Call processing units 111, 112 ... ATM-LAN 11A, 11B ... Call processing units 131-133 ... ATM-LAN 134 ... IWU (inter-network connection device) 141 ... ATM switch 142 ... CLSF processing section (connectionless service function processing section) 143 ... Call processing section 144 ... IWU management section 14A, 14B ... Input processing section 14X, 14Y ... Output processing units 151-157 ... Switch nodes 15A-15J ... Terminals 171-1 73 ... Call processing units 181-183 ... Call processing units 191-193 ... ATM-LAN 201 ... ATM backbone networks 202-204 ... ATM-LAN 20A-20C ... IWU (inter-network connection device) 211-217 ... Switch nodes 21A- 21J ... Terminal 311 ... ATM-LAN 312 ... ATM backbone network 31A-31B ... Terminal 31P ... IWU (inter-network connection device) 31X ... CLSF processing unit (connectionless service function processing unit) 361 ... ATM interface 362 ... ARP filter unit 363 ... ARP processing unit 364 ... Inserting unit 365 ... Bus interfaces 411, 412 ... Terminal 413 ... ARS (address resolution server) 414 ... CLSF processing unit (connectionless service function processing unit) 415 ... IWU (inter-network connection device) 41A ~ 41C ... TM connection 46A to 46E ... ATM connection 471 to 474 ... Sub network (ATM network) 475 ... Public network 476 to 479 ... IWU (inter-network connection device) 47A to 47F ... Terminals 481 to 484 ... ARS (address resolution server) 485-487 ... ATM connection 491-494 ... CLSF processing unit (connectionless service function processing unit) 495-49B ... ATM connection 571-576 ... ATM connection 581-584 ... ATM connection 591-59C ... ATM connection 60xx ... ATM connection 611 ... 61A ... ATM connections 621-62A ... ATM connections 63A-63B ... Terminals 631-634 ... Sub-network (ATM network) 635 ... Public networks 636-639 ... IWU (inter-network) Connection device) 63D to 63G ... ARS (address resolution server) 63H to 63L ... CLSF processing unit outside the subnetwork (connectionless service function processing unit) 63M to 63Q ... CLSF processing unit inside the subnetwork (connectionless service function) Processors 641 to 646 ... ATM connections 651 to 656 ... ATM connections 661 to 66C ... ATM connections 691 to 699 ... ATM connections 701 to 706 ... Sub-networks (ATM networks) 707, 708 ... Public networks 70A, 70B ... Terminals 70xx ... CLSF processing unit (connectionless service function processing unit) 70E to 70M ... IWU (inter-network connection device) 771 to 776 ... ATM connections 781 to 784 ... ATM connections 791 to 797 ... ATM connexion 801 to 805 ... ATM connection 811 ... CLSF processing unit (connectionless service function processing unit) 812 to 814 ... ATM connection 831 to 834 ... ATM connection 851 ... Sub network (ATM network) 861 to 863 ... Sub network (ATM network) ) 864 ... Public network 871 to 874 ... CLSF processing unit (connectionless service function processing unit) 87A to 87C ... Terminals 881 to 884 ... ATM connections 891 to 892 ... ATM connections 901 to 905 ... ATM connections 911 to 913 ... ATM connections

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Ezaki             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research and Development Center F-term (reference) 5K030 HA10 HC15 HD01 HD09 LB18                 5K033 CB08 DA05 DB16 DB18 EC03

Claims (4)

[Claims] 1. A plurality of ATs operated in an asynchronous transfer mode
An M network, a plurality of terminals respectively accommodated in the plurality of ATM networks, a plurality of datagram servers provided in at least one of the plurality of ATM networks, and a plurality of ATM networks provided between the plurality of ATM networks. And an inter-network connecting device for performing internetworking between the ATM networks, wherein the inter-network connecting device is an ATM connected to the inter-network connecting device.
A for requesting address resolution from the network
In response to the RP request, if the target node of the address resolution does not exist in the ATM network connected to the inter-network connecting apparatus, the A for the ARP request is returned with the reply of the ATM address of the ATM connection connecting to the inter-network connecting apparatus.
A response means for making an RP response and an AT replied by an ARP response from this response means
A connection terminal that connects the first ATM connection indicated by the M address and the second ATM connection set between the network connecting device and the datagram server, and the datagram transmitting terminal, An ATM communication system characterized in that the datagram server and the datagram server are directly connected by an ATM connection. 2. A plurality of ATs operated in an asynchronous transfer mode
An M network, a plurality of terminals respectively accommodated in the plurality of ATM networks, a plurality of datagram servers provided in at least one of the plurality of ATM networks, and a plurality of ATM networks provided between the plurality of ATM networks. An inter-network connecting device for internetworking between the ATM networks, wherein the inter-network connecting device is a routing protocol terminating means and an address resolution from the first ATM network connected to the inter-network connecting device. And a notification means for notifying the ARP server for performing the address resolution when receiving the ARP request for requesting the address, and the address resolution for the information passed by the notification means. First A indicated by the ATM address returned by the address resolution response from the application server M connection and connection connecting means for connecting the inter-network connection device and the second ATM connection set between the datagram server, and between the datagram transmission terminal and the datagram server. An ATM communication system characterized by direct connection through an ATM connection. 3. The connection connecting means connects the first ATM connection and the second ATM connection by at least one of an ATM cell header converting means and an ATM cell switching means, and the datagram server. 4. The ATM communication system according to claim 2 or 3, wherein the increase / decrease or increase / decrease is performed by setting at least one of the ATM cell header converting means and the ATM cell switching means. 4. An ATM network operated in an asynchronous transfer mode, and a plurality of terminals accommodated in the ATM network, wherein the terminal is an address addressed to the terminal from an ATM cell from the ATM network. ARP request cell extracting means for extracting an ARP request cell for requesting a resolution, and an ARP response for making a response to the request for the address resolution based on the ARP request cell extracted by the ARP request cell. An ARP response cell generating means for generating a cell, and a multiplexing means for multiplexing the ARP response cell generated by the ARP response cell generating means with an ATM cell stream sent from the terminal device. ATM
Communications system.