JPH11215156A - Inter-network connecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inter-network connecting device which can simplify route searching processing by using an NHRP protocol and can transfer data at a high speed in ATM networks. SOLUTION: When data are transferred to a second terminal equipment host D connected to a second non-ATM network LANe2 from a first terminal equipment host S connected to a first non-ATM network LANe1 through ATM networks LANa1 and LANa2, the data transfer is made based on the content of the medium access control address of the second terminal equipment host D after a communication link is established between a first inter-network connecting device IWU1 which connects the first non-ATM network LANe1 to the ATM networks LANa1 and LANa2 and a second inter-network connecting device IWU3 which connects the networks LANa1 and LANa2 to the network LANe2. Consequently, the data transfer can be made at a high speed, because an NHRP protocol becomes usable in the ATM networks and route searching processing can be made in corporation with an adjacent inter- network connecting device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ATM network and a non-AT
An inter-network connecting device that connects communication networks such as a repeater, a router, and a gateway in a communication network in which M networks are mixed.

[0002]

2. Description of the Related Art In recent years, a wide variety of local area networks (LANs) have been interconnected due to the spread of the Internet, and a huge worldwide network has been constructed. As a protocol for interconnecting LANs connected to the Internet, an Internet Protocol (IP protocol) is used as a standard. This IP protocol is a technology of IAB, an Internet-related academic society (control organization). It is standardized by IETF, a sub-organization under consideration.
In the connection using the IP protocol, an IP address is used to identify each computer, and the IP address is further divided into a network address indicating a network and a host address indicating a host machine. And
In order to transfer data between terminals having IP addresses having different network addresses, a repeater called a router is required between networks to which each terminal belongs. Note that data is transferred in units called packets, and large data is divided into several packets and transferred. A packet used in the IP protocol has an IP at the beginning of the data.
It is called an IP packet having an IP header containing an address. When this IP protocol is transferred by ATM, the logical link control LLC or SN is added to the head of the IP packet.
An AP or the like is added to perform encapsulation, and the encapsulated packet is converted into an ATM cell, which is a finer unit,
A VP or virtual call VC is added to each ATM cell as an ATM header and transferred. Where ATM
A conventional example in which an Ethernet network is connected as an example of a network and a non-ATM network will be described. A router is installed between the ATM network and the Ethernet network as an inter-network connection device. In the router, a VP / VC for the ATM network and a correspondence table having IP addresses corresponding to each of the routers are provided. A correspondence table having Ethernet addresses and IP addresses corresponding to the respective Ethernet addresses is registered. The above correspondence table is not only a correspondence table relating to an ATM network or an Ethernet network directly connected to the router, but also an ATM network or an directly connected ATM network which is indirectly connected via the directly connected ATM network. A correspondence table having IP addresses corresponding to VP / VCs and Ethernet addresses of distant hierarchical networks such as an Ethernet network indirectly connected to the Ethernet network via a router is also registered.

For example, a terminal (client) S connected to an ATM network via the above-described Ethernet network and a router.
Considering the case where data is transferred to a terminal (client) D connected to the Ethernet network, the data is transferred within the first ATM network through a normal network and reaches a router. Based on the IP address received from S, search for the Ethernet address of client D registered in the correspondence table. When the Ethernet address of the client D is found, the data is sent to the client D. The above-described search for the Ethernet address based on the IP address in the router is repeated each time a packet of data is received by the router. Each time, an appropriate Ethernet address is searched and the data is transferred to the Ethernet address. As described above, when data is transferred by the router, the router refers to the IP header in the IP packet, including the search for the Ethernet address and the search for the VP / VC in the ATM network when transferring data in the reverse direction. Thus, the optimum route is searched from the correspondence table (route information table), and the IP packet is transferred according to the searched route. By the way, in data transfer, a procedure (protocol) is defined, and the protocol is defined by a hierarchical model. First layer (physical layer: physical conditions and electrical operation of terminals and exchanges, etc.) Second layer (data link layer: between adjacent devices, for example, between terminals and exchanges and repeaters, and between exchanges ), And a third layer (network layer: a communication link control rule between terminal terminals that exchange data).

[0004] Considering the Ethernet address search in the router by this hierarchical model, the search (or route search) is performed based on the IP address of the IP protocol which is the third layer protocol. In the case of the data transfer in, a MAC (media access control) address which is a physical address of the first layer is required, so that the MAC address is searched from the IP address. The MAC address is, for example, Ethernet address for Ethernet, VP / V for ATM
C. When searching for the MAC address, an address resolution procedure according to the network to be searched is used. The address resolution procedure in the Ethernet network uses a broadcast that sends an IP address to all terminals connected to the Ethernet network, and the corresponding terminal
The MAC address is resolved by responding with the MAC address corresponding to the address. In the address resolution procedure in the ATM network, broadcast such as the Ethernet network cannot be used. Therefore, each terminal connected to the ATM network previously writes its own MAC address and its corresponding IP address in the ATM network. Registered in the connected address resolution server (ARS: address resolution server),
The RS is queried for the MAC address corresponding to the IP address to resolve the MAC address. On the other hand, in an ATM network, VP / VP is used not only within the ATM network but also between LANs where ATM networks having different network addresses are connected.
The NHRP protocol is known as an address resolution protocol capable of performing communication by directly setting a link only by the VC, and the NHRP protocol is being developed by IETF.

[0005] In this NHRP protocol, it is premised that all connected networks must be ATM networks (or, if they are other networks, all networks of the same system).
No inter-network connecting device such as a router is connected between the ATM networks, and each ATM network has a MAC address (V) corresponding to the IP address of each terminal as in the conventional ARS.
NHRP server (NR) for registering P / VC
S) is installed, and each terminal (NHR) on each ATM network is installed.
P client: NHC) sends the MAC address (VP / VC) corresponding to the IP address of its own terminal to its NHS
Register in advance. A using the NHRP protocol
In the TM network, the data transmission source NHC transmits an IP address to the NHS and inquires of a destination MAC address. Then, the NHS first determines whether the inquired IP address is under the control of its own network, and if it is under its own control, the MAC address (VP / VC) in the NRS cache is determined. ) Is the source N
Respond to HC. If the queried IP address is not under its own control, the NRS cache is searched for a routing table indicating the next transfer destination (next hop: next hop) set in advance, and the AT of the next hop is searched.
The IP address is transmitted to the NHS of the M network to inquire about the MAC address (VP / VC). The same processing as described above is performed also in the NHS of the next hop inquired, and the NHS that finally manages the destination NHC is controlled by its own network under the MAC address (VP / VC) corresponding to the IP address. ), And if there is an NHS to relay the VP / VC, a link is established by responding to the source NHC via the relay NHS, and a link is established from the source NHC to the destination NHC. Direct communication using VP / VC becomes possible.

[0006]

However, there is an N-type communication system that allows direct communication from one terminal to a terminal on another network by VP / VC.
The HRP protocol requires that all networks be ATM networks (or all networks have the same scheme) and cannot be used on the Internet or the like where other networks coexist. Therefore, in order to connect an ATM network other than such an ATM network to the ATM network, as described in the above-mentioned conventional technique, an inter-network connection device (router) is used to directly or indirectly connect the inside of the router. IP protocol and MAC of individual terminal of each network
A correspondence table (route information table) corresponding to the addresses is prepared in advance, and the router extracts an IP address from the packet every time there is communication (each time a packet is received), and the IP address is stored in the correspondence table. It is necessary to search all the correspondence tables to check whether or not the MAC address is registered. If there is, the corresponding MAC address is responded. If not, it is necessary to make an inquiry to the next adjacent router. However, in such an inter-network connection device (router) that connects the non-ATM network and the ATM network, the IP address is searched from all registered correspondence tables, and the registered correspondence table is also stored in the router. Since not only the directly connected network but also the indirectly connected network correspondence table is searched, it takes time to search for the optimum route determined by the search result. Since the router takes time, such a boundary portion of the LAN becomes a bottleneck and lowers the transfer capability of the entire network as compared with the transfer capability of an individual network. The present invention has been made in view of the above problems, and is intended to provide an NHRP even for a network connecting a non-ATM network and an ATM network.
It is an object of the present invention to provide an inter-network connection device capable of simplifying a route search process using a protocol and enabling high-speed transfer in an ATM network.

[0007]

In order to achieve the above object, the present invention provides an inter-network connecting device for connecting respective networks of a communication network in which a non-ATM network and an ATM network coexist. A
When data is transferred from a first terminal device connected to a TM network to a second terminal device connected to a second non-ATM network via an ATM network, the first non-ATM network and the ATM
A first inter-network connecting device for connecting a network and a first inter-network connecting device between a second inter-network connecting device connecting the ATM network and the second non-ATM network; After the communication link is established, data transfer is performed based on the contents of the MAC (media access control) address of the second terminal device.
The AC address simplifies the route search process in the network connection device, so that the processing load is reduced, and the NHRP protocol can be used in the ATM network.
In the RP protocol, a route search process is performed in cooperation with an adjacent network connection device, so that high-speed data transfer is possible.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described in detail with reference to the drawings. FIG. 1 is a network configuration diagram showing an embodiment of the inter-network connection device of the present invention. In FIG. 1, LANe1 and LANe2 are local area networks (LANs) of an Ethernet network,
Na1 and LANa2 are LANs of an ATM network. The host S is one of the terminals connected to the Ethernet network LANe1.
In the present embodiment, the terminal is a terminal on the transmission side of an IP packet including an IP address. Then, the network connection device I
WU1 is an Ethernet network LANe1 and an ATM network LANa
1, the network connecting device IWU2 is between the ATM network LANa1 and the ATM network LANa2, and the network connecting device IWU3 is
It is installed at each boundary between the M network LANa2 and the Ethernet network LANe2. The host D is one of the terminals connected to the Ethernet network LANe2. In the present embodiment, the host D is a terminal on the receiving side of the IP packet transmitted from the host S. The inter-network connecting device IWU1 includes a correspondence table between the IP addresses of the terminal devices connected to the Ethernet network LANe1 and the corresponding Ethernet addresses, and the IP addresses of the terminal devices connected to the ATM network LANa1 and the corresponding VPs. A / VC correspondence table is registered in advance. Similarly, the network connection device IWU2 has a correspondence table of the IP addresses of the terminal devices connected to the ATM network LANa1 and the corresponding VP / VCs, and A
An IP address of a terminal device connected to the TM network LANa2 and a corresponding table of VP / VC corresponding to the IP address are registered in advance, and the inter-network connecting device IWU3 has the ATM network LANa.
Table of the IP address of the terminal device connected to the terminal 2 and the corresponding VP / VC, and the Ethernet network LANe
A correspondence table between the IP address of the terminal device connected to the terminal 2 and the corresponding Ethernet address is registered in advance. The registration itself is the same as in the case where a router is connected between the conventional networks, and the IP address and the MAC address of the terminal device, which is the client, are registered for all the networks directly connected to the network to which the client belongs. It is assumed that it is registered in the network connection device.

In the above configuration, the host S to the host D
The operation in the case of communicating with the server will be described below. In FIG. 1, the host S of the Ethernet network LANe1 sends an IP address of the host D and a request to resolve the IP address of the host D to the network connecting device IWU1.
Upon receiving the request for resolving the IP address of the host D, the internetwork connection device IWU1 determines whether or not the terminal device managed by itself has the IP address of the host D by checking the Ethernet address and the IP address of each terminal device. ATM table in which the correspondence table of the registered Ethernet network LANe1 and the VP / VC and IP address of each terminal device are registered correspondingly.
By searching the correspondence table of the network LANa1, it is confirmed whether or not the solution request can be answered. In FIG. 1, in the case of the present embodiment, since the IP address of the host D is not registered under the control of the inter-network connecting device IWU1, it cannot respond to the solution request, so that the network is connected via the ATM network LANa1. An inquiry is made to the inter-connecting device IWU2 for a request to resolve the IP address of the host D to the terminal device under management.
Upon receiving the request for resolving the IP address of the host D, the inter-network connecting device IWU2 determines whether or not the terminal device managed by the own device has the IP address of the host D by the V of each terminal device.
Table of ATM network LANa1 in which P / VC and IP address are registered correspondingly, and VP / VC and IP of each terminal device
By searching a correspondence table of the ATM network LANa2 registered with the corresponding address, it is confirmed whether or not the answer to the solution request can be answered. In FIG. 1, in the case of this embodiment,
Since the IP address of the host D is not registered under the control of the internetwork connecting device IWU2, it cannot respond to the solution request, so that the internetwork connecting device I via the ATM network LANa2.
The WU 3 inquires the terminal device under management of a request to resolve the IP address of the host D.

[0010] Upon receiving the request for resolving the IP address of the host D, the inter-network connecting device IWU3 determines whether or not the terminal device under its own control has the IP address of the host D by checking the VP / VC and IP of each terminal device. Whether the answer to the solution request can be answered by searching the correspondence table of the ATM network LANa2 registered corresponding to the address and the correspondence table of the Ethernet network LANe2 registered corresponding to the Ethernet address and the IP address of each terminal device. Check. In the case of this embodiment, since the host D exists in the Ethernet network LANe2 and the host D exists under the control of the internetwork connection device IWU3, the IP address of the host D from the internetwork connection device IWU2 is provided.
Although it is possible to respond to the inquiry about the address resolution request, the Ethernet address is registered as the MAC address corresponding to the IP address in the correspondence table regarding the host D of the internetwork connecting device IWU3. Here, for example, even if the Ethernet address of the host D is sent to the internetwork connection device IWU2 as a response to the internetwork connection device IWU2,
Since it is a connection device between networks, VP / VC is used as a MAC address, and the host D cannot understand even if it receives an Ethernet address. Therefore, the internetwork connecting device IWU3 of the present embodiment generates a new VP / VC corresponding to the Ethernet address of the host D and allocates it to the ATM network LANa2 side of the internetwork connecting device IWU3.
The Ethernet address of the host D and the new VP / V
The association of C is registered in the network connection device IWU3.

The process in the IWU 3 will be described with reference to FIG. 2, which is a diagram showing the process in the network connection device IWU 3 in FIG. In FIG. 2, the process of FIG. 1 is illustrated in an easy-to-understand manner. When the IP address of the host D at the upper left in the drawing is received, it is registered in advance in the internetwork connecting device IWU3 based on the IP address. Then, the Ethernet address of the host D is retrieved from the correspondence table.
Then, the obtained Ethernet address of the host D is set to A.
Since the IWU2 side cannot understand the Ethernet address even if it is sent to the inter-network connecting device IWU2 connecting the TM networks, the VP / V which can be understood by the inter-network connecting device IWU2.
C, and associates the generated VP / VC with the Ethernet address of the host D to make the network connection device IWU3
And sends the VP / VC as a response to the inquiry about the solution request from the network connection device IWU2.
In FIG. 1, a new VP / VC generated in association with the host D's Ethernet address by the network connecting device IWU 3 is used as a response to the network connecting device IWU 2 instead of the actual Ethernet address of the host D.
It is transmitted to the inter-network connection device IWU2 via the TM network LANa2. In FIG. 1, in the network connection device IWU2 that has received the new VP / VC, the received V
This time, the P / VC is transmitted to the interworking apparatus IWU1 via the ATM network LANa1 as a response to the inquiry from the interworking apparatus IWU1. In the internetwork connection device IWU1 that has received the VP / VC as a response to the inquiry for the resolution request, the VP / VC is associated with the Ethernet address of the host S used at the time of inquiring the resolution request, and is associated with the internetwork connection device. Register with IWU1.

In FIG. 1, the network connecting device IWU1 is
Using the Ethernet address of the host S, it becomes possible to send an IP packet addressed to the host D, that is, the fact that the communication path from the host S to the host D has been established to the host S of the Ethernet network LANe1. Notice. In FIG. 1, the host S sends to the host D data of an IP packet to which the Ethernet address of the host S is added. The internetwork connection device IWU1 extracts the Ethernet address of the host S from the data of the received IP packet, and determines the VP / VC corresponding to the extracted Ethernet address from the correspondence between the VP / VC registered above and the Ethernet address. ATM using data
It is sent to the inter-network connecting device IWU2 via the network LANa1. In the inter-network connecting device IWU2 which has received the data using the VP / VC, a normal M in the ATM network is used.
Since the processing is performed in the same manner as the VP / VC as the AC address, the data using the VP / VC is transmitted to the network connection device IW.
Arrives at U3. When the VP / VC is extracted from the data arriving at the inter-network connection device IWU3 via the ATM network LANa2 in the inter-network connection device IWU3, the inter-network connection device IWU3 is extracted from the extracted VP / VC.
The Ethernet address of the host D is searched by associating the VP / VC corresponding to the Ethernet address of the host D registered in the.

The network connection device IWU3 adds the Ethernet address of the host D obtained by the search to the IP header of the received data and sends it to the Ethernet network LANe2. The data transmitted to the Ethernet network LANe2 arrives at the host D in the Ethernet network LANe2 based on the added Ethernet address. in this way,
In the present embodiment, the host S after the communication path is established
In the transfer of data from the host to the host D, data transfer is performed according to the NHRP protocol without using an IP address between inter-network connecting apparatuses having only an ATM network therebetween. FIG. 3 is a diagram comparing the configuration of a router, which is a conventional network connection device, with the configuration of the network connection device of the present invention, in which data transfer is performed in the network connection device without using the IP address. It will be described using FIG. In the conventional router of FIG.
In connection to the network, the physical layer on the Ethernet network side, MA
After reaching the IP layer via the C layer, LLC layer, and SNAP layer, the SNAP layer, LLC layer, AAL layer,
The data is transmitted to the ATM network via the ATM layer and the physical layer. In the network connection device of the present invention of (b), the IP layer of the conventional router of (a) is omitted, and the S side on the Ethernet side is omitted.
The NAP layer connects to the SNAP layer on the ATM side. That is, the time can be reduced by not passing through the IP layer. In this embodiment, the Ethernet network is used as the non-ATM network. However, for example, even in a combination of another non-ATM network and the ATM network, the Ethernet address is changed to the MAC address used in the non-AYM network. The present invention can be implemented.

[0014]

According to the present invention, as described above, the first
After the communication link between the second network connection device and the second network connection device is established, data transfer is performed based on the contents of the MAC (media access control) address of the second terminal device, thereby establishing the network connection. Since the route search processing in the device is simplified, the processing load is reduced, and the NHRP protocol can be used in the ATM network.
In the protocol, a route search process is performed in cooperation with an adjacent network connection device, so that high-speed data transfer is possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a process in an internetwork connecting device IWU3 of FIG. 1;

FIG. 3A is a diagram showing a configuration of a router which is a conventional network connection device. FIG. 2B is a diagram illustrating a configuration of the network connection apparatus of the present invention.

[Explanation of symbols]

Hosts S, D: terminal devices, LANe1-2: Ethernet network (non-ATM network), LANa1-2: A
TM network, IWU1-3 ... network connection device

Claims (5)

[Claims] An inter-network connecting device for connecting respective networks of a communication network in which a non-ATM network and an ATM network coexist.
When transferring data from a first terminal device connected to an M network to a second terminal device connected to a second non-ATM network via an ATM network, the first non-ATM network and the ATM A first inter-network connecting device for connecting a network and a first inter-network connecting device between a second inter-network connecting device connecting the ATM network and the second non-ATM network; An inter-network connection device, wherein after establishing a communication link between them, data transfer is performed based on the contents of a MAC (media access control) address of the second terminal device. 2. When establishing a communication link between said first and second internetworking devices, said internetworking device communicates with said non-ATM
Network specific addresses and Internet Protocol (I
2. The network connection device according to claim 1, wherein a P) address is used. 3. When establishing a communication link between said first and second network connecting devices, said first network connecting device manages an address of a target communication partner under the control of its own network connecting device. 3. The network connection device according to claim 2, wherein when the is not found, an inquiry is made to an adjacent network connection device. 4. When establishing a communication link between the first and second network connecting devices, the second network connecting device assigns a MAC address of the second terminal device to a second network. And the MAC of the second terminal device.
The internetwork connection apparatus according to any one of claims 1 to 3, wherein the address is transmitted to and registered in the first internetwork connection apparatus. 5. The network connection device according to claim 1, wherein an NHRP protocol is used for data transfer between the first and second network connection devices. .