JP2923921B1 - Packet transfer method - Google Patents

Abstract

A network having a point-to-point link between routers of a non-ATM network via an ATM network.
A system that connects the TM conversion nodes directly by the ATM logical connection and bypasses the router network is realized. SOLUTION: After resolving an ATM address of a translation node 54 at an exit of a router network from a destination IP address 32 of an IP packet from a link of a non-ATM interface and setting a shortcut path, a point-to-point link identifier 31 and a destination are set. The packet and the path are determined by associating the IP address 32 and the shortcut path identifier 34, and the IP address 41 received by the shortcut path receiving node 54 and the link identifier to which the received packet is to be transmitted are transmitted to the link. By performing the transfer processing from the shortcut to the non-ATM interface by associating the header information 43 and the like at the time,
Achieve bypass distribution of the router network.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a packet transfer system, and more particularly, to a packet transfer system for connecting a point-to-point link and an ATM logical connection via a conversion node.

[0002]

2. Description of the Related Art In recent years, demand for data communication has been increasing, and a DDX network has been completed as a switching network dedicated to data communication, and a DDX network used for transferring continuously generated data information has been completed.
There are -C circuit switching and packet switching in which information divided into blocks is transferred with an address attached thereto, and packet transfer with high line efficiency has attracted attention.

Recently, a plurality of LANs (Local Area Nets) have been used.
work: local area communication network) as a protocol for constructing a large-scale packet transfer network.
TCP / IP (Transmission Control Protocol / Intern)
et Protocol) has been used as a standard, and the large-scale packet transfer network constructed by this protocol has been called the Internet.

[0004] In a network using this TCP / IP, a terminal group for broadcasting IP packets called a subnet is used as a unit of communication, and a router is used for connection between these subnets. Is used.

[0005] The router has a plurality of network interfaces and terminates processing up to the network layer. On the other hand, in order to speed up the network, a technology for constructing a TCP / IP network using a high-speed ATM (Asynchronous Transfer Mode) switch between routers has been developed.

For example, OSI (Open Systems Interconn)
Section: Open System Interconnection) In the hierarchical model, ATM is used for the second and lower layers, and TCP is used for the third and fourth layers.
The communication method when using the / IP protocol is ATM
Forum (The ATM Forum), etc.
Specifications such as TM Forum AF-MPOA-0087.000 "have been published." ATM Forum / AF-MPOA-0087.000 Multiprotocol O
ver ATM Version 1.0 (LetterBallot) Andre N. Fredett
e-authored, published May 29, 1997, section 3.6, FIG.
ure 6 ", the MPOA (Multipro
tocol over ATM: mechanism for transferring multiprotocols)
An interface device that has an interface with a non-ATM network such as Ethernet or Token Ring, and an interface with an ATM network, and is an edge device serving as a relay node between the non-ATM network and the ATM network, or an interface with the ATM network. A terminal on an ATM network having only an ATM network is configured as an MPOA client (MPC), an interface with the ATM network is provided, and a device serving as a router node is configured as an MPOA server (MPS). That is, non-A
The TM network is connected to the ATM network via the MPC and the MPS.

[0007] MPOA standardized for multi-protocol transfer is a LAN which is a protocol that enables terminals on a non-ATM network such as Ethernet or Token Ring and terminals on the ATM network to belong to the same subnet. The emulation (LANE) protocol is used. MPC, which is an edge device, uses a non-AT
When a MAC (Media Access Control) frame from the M network is received, the MAC frame is transferred onto the ATM network after encapsulation according to the LANE specification. An IP packet transmitted from a node on a non-ATM network to a node on a different subnet is delivered to an MPS, which is a router located at the boundary of the subnet, and is transferred to another subnet using an IP routing function. Is done.

Normally, an IP packet delivered from a non-ATM network to another non-ATM network via an ATM network employing the MPOA method is transmitted from a node on the non-ATM network to an entrance located at the entrance of the ATM network. MPC → Ingress MPS which is the first router after entering the ATM network → MPS → Egress MPS which is the last router on the delivery route on the ATM network → Exit MPC which is the exit from the ATM network → Other non-ATM which is the destination Delivery is performed by a route called a node on the network. This route is MPO
In A, it is called a default (standard) delivery route.

When a certain amount or more of packets are delivered to a specific destination IP address within a specific time on the above-mentioned default delivery route, the MPOA system uses a router MP.
The creation of a shortcut path bypassing S is started.

[0010] The count of the packet delivery amount is M
Performed on a PC. That is, the MPC has a function of counting packets delivered via the MPS on the ATM network for each destination IP address.

In order to create the above-described shortcut path, the MPC sends a packet having a destination IP address exceeding a certain flow rate to the AT MP of the egress MPC that exits the ATM network.
A process for resolving the M address is started. Specifically, M
The PC sends an address resolution request (Address Resolution Request) describing a destination IP address exceeding a certain flow rate.
Transmission is performed to the next MPS on the default delivery route. When the MPS receives this address resolution request, the MPS in the next stage according to the IP routing table
Transfer to

[0012] When transmitting to the node on the non-ATM network via the egress MPC which is the egress from the ATM network as the next destination, the MPS transfers the address resolution request as it is. Rather, the egress MPC attaches the MAC frame header information to be added when the IP packet is transferred on the non-ATM network, and sends the cache generation request (Ca
che Imposition Request) to the exit MPC.

The egress MPC that has received the packet returns the ATM address of its own node to the MPS to create a shortcut path, and refers to the egress cache referred to when transmitting the shortcutted packet to the non-ATM network side. Then, the destination IP address of the packet to be short-cut and the MAC frame header information to be attached are written. Upon receiving the reply from the egress MPC, the MPS transfers the ATM address described in the reply to the source MPS as an Address Resolution Response. This address resolution response is returned to the ingress MPC that sent the address resolution request, which is the entrance to the ATM network, and the ingress MPC refers to the destination IP address and the ATM address of the address resolution response when transferring the address resolution response to the shortcut delivery route. Write to the entry cache.

When these processes are completed, the ingress MPC provides an ATM logical connection (VCC: Virtual Channel Connection) as a shortcut delivery path to the egress MPC.
To standard ATM signaling procedures (ATM Forum UNI
Set using 3.0 / 3.1 / 4.0 or ITU-TQ.2931). After this route setting, the IP packet having the destination IP address is transferred to the shortcut ATM logical connection, which is the shortcut delivery route, after the header of the MAC frame is deleted on the ingress MPC, and
The PC attaches the MAC frame header of the egress cache corresponding to the destination IP address described in the packet, and then transmits the packet to the non-ATM network side.

According to the above-described processing, the distribution route on the ATM network can be transmitted without passing through the layer 3 processing of the router.
Delivery of IP packets becomes possible only through the TM exchange network,
Higher-speed packet transfer is realized.

[0016]

The conventional MPOA technique is based on non-A of an ingress MPC and an egress MPC of an ATM network.
As the packet interface on the TM side, only IEEE LAN such as Ethernet and token ring is specified. Also, some functions of the MPOA method are realized based on the functions of LAN emulation. For this reason, the MPOA method can be used only in a non-ATM network in which the layer 2 uses the MAC frame.

On the other hand, the network to which the present invention is applied is a non-ATM interface accommodated by an entry node and an exit node of an ATM network, and is a DS interface.
1, DS3, digital leased line, frame relay, P
This system handles point-to-point links such as PP links and xDSL.

The network to which the present invention is applied will be described in detail with reference to the drawings. FIG. 25 (a)
Shows an example of a configuration diagram of a network to which the present invention is applied. In the figure, an ATM network 50 includes a plurality of ATs.
This is a network configured by connecting an M switch and a node having an ATM interface (I / F) by an ATM link.

The ATM network 50 is connected to an IP router 152 and an IP router 153 having an IP packet routing function, and a header conversion type ATM conversion node 151 and a header conversion type ATM conversion node 154 by an ATM link.

The header conversion type ATM conversion nodes 151 and 154 are connected to the ATM network 50 by an ATM link, and are connected to digital leased lines such as DS1 and DS3 and non-ATM network systems such as a frame relay, a PPP link and xDSL. The links are connected to IP routers 55, 56, 57 and IP routers 58, 59, 60 by point-to-point links (hereinafter referred to as non-ATM network point-to-point links).

FIG. 25 (b) shows the link configuration in the above-mentioned network by a thick line. The header conversion type ATM conversion node 151 sets an ATM logical connection (VCC) corresponding to a non-ATM network point-to-point link with the IP router 55 up to the IP router 152.

Similarly, the header conversion type ATM conversion node 151 sets an ATM logical connection corresponding to a non-ATM network point-to-point link with the IP routers 56 and 57 to the IP router 152. The header conversion type A
Similarly for the TM conversion node 154, the IP router 5
The ATM logical connection corresponding to the non-ATM network point-to-point link between the IP routers 8, 9, and 60 is set up to the IP router 153. Also, the IP router 152 and I
Between the P routers 153, the ATM logical connection (V
CC) for data communication.

FIG. 26 shows the internal configuration of the header conversion type ATM conversion node. The header conversion type ATM conversion nodes 151 and 152 are non-ATM network point-to-point link I / Fs (interfaces) 101 for transmitting and receiving packets from the non-ATM network point-to-point link.
An ATM logical connection I / F 102 having functions such as setting and management of an ATM logical connection on the ATM link of the ATM network 50, transmission and reception of ATM cells, packet conversion of ATM cells, and a packet header handled on the ATM logical connection A header conversion processing unit 110 having a function of converting a packet header used on a non-ATM network point-to-point link; a link correspondence table 104 holding a correspondence between an ATM logical connection and a non-ATM network point-to-point link; And a packet transfer unit 103 which connects these functional units to perform a packet transfer process.

The internal configuration of the IP routers 152 and 153 connected to the ATM network 50 shown in FIG. 25 will be described with reference to FIG. The IP routers 152 and 153 connected to the ATM network 50 are connected to an ATM on an ATM network ATM link.
Setting and management of logical connections, transmission and reception of ATM cells,
An ATM logical connection I / F 121 having a function of converting an ATM cell packet, a routing table 123 for storing next-stage delivery destination information indicating to which node an IP packet is to be delivered next, a non-ATM network point-to-point I connected to the ATM network by a link
An ATM logical connection management table 125 for managing which ATM logical connection the IP address for identifying the P router corresponds to.

For example, as shown in FIG. 25, when an IP packet is transmitted from the IP router 55 to the IP router 58 in the network targeted by the present invention, the following processing is performed.

The IP packet is provided with a layer 2 header for a non-ATM network point-to-point link in the IP router 55, and the header conversion type ATM conversion node 151 is provided using the non-ATM network point-to-point link.
Sent to.

The header conversion type ATM conversion node 151
Layer 2 for the non-ATM network point-to-point link
Received at the non-ATM network point-to-point link I / F 101,
The packet is transferred to the packet transfer unit 103.

The packet transfer unit 103 converts the header for the non-ATM network point-to-point link added to the IP packet into
AAL (ATM) which is a layer 2 header used in the TM network
Adaptation Layer) 5, and converts the ATM logical connection corresponding to the non-ATM network point-to-point link from which the packet was received to the link correspondence table 104.
And transfers it to the ATM logical connection I / F 102. The ATM logical connection I / F 102 converts the IP packet to which the header used in the ATM network has been added into an ATM cell, and then transmits the ATM cell to the ATM logical connection determined by the link correspondence table 104.

An ATM cellized packet transmitted to the ATM logical connection is transmitted to the IP router 152.
, The packet is received by the ATM logical connection I / F 121, converted from an ATM cell into a packet, and transferred to the packet delivery unit 122. The packet delivery unit 122
Deletes the layer 2 header, searches the routing table 123 based on the destination IP address of the packet, and determines the next destination. In this case, the next destination is determined as the IP router 153 by the processing of the IP router 152.

If the delivery destination is not a connection described in the ATM logical connection management table 125 corresponding to the IP address, the packet delivery unit 122 attaches a header corresponding to the delivery destination and transmits the header to the next delivery destination. The ATM logical connection I / F 12
1, the ATM logical connection I / F 121 converts the packet into a cell, and transmits the cell to the IP router 153.

The IP router 153 that has received the ATM cell generated from the packet by the processing of the IP router 152
Since the ATM logical connection of the next stage is determined in the same manner as in the IP router 152, the ATM logical connection of the next stage is held in the IP address corresponding ATM logical connection management table 125. After attaching an AAL5 header to the packet, the ATM logical connection I / F 12 is added to the ATM logical connection.
After the ATM cell conversion in step 1 is performed, the cell is transmitted.

The packetized cell is received by the header conversion type ATM conversion node 154, packetized by the ATM logical connection I / F 121, and transferred to the packet transfer unit 103.

The packet transfer unit 103 converts the AAL5 header added to the packet into a layer 2 header for a non-ATM network point-to-point link by the function of the header conversion processing unit 110,
After the non-ATM network point-to-point link corresponding to the M logical connection is obtained from the link correspondence table 104, the non-ATM network point-to-point link I / F
Transfer to 101.

According to the link correspondence table 104,
Layer 2 for the non-ATM network point-to-point link
The packet provided with the header is transmitted to the non-ATM network point-to-point link, and transmitted to the IP router 58.

The second network to which the present invention is applied will be described with reference to the drawings.

FIGS. 28A and 28B respectively show the second
1 shows an example of a configuration diagram of a network and a link configuration in the network.

FIG. 29 is a view showing a portion 351 of FIG.
FIG. 30 shows the internal configuration of the tunneling type ATM conversion node described in 354, and FIG.
53 shows an internal configuration of an IP router capable of processing a FR (frame relay) header connected to the ATM network described in 53.

In this example, the non-ATM network point-to-point link is FR (frame relay network).
Is described.

For example, in the second network to which the present invention is applied, the IP router 55 transmits the
In the case where an IP packet is transmitted to No. 8, the following processing is performed.

The IP packet is provided with an FR header, which is a layer 2 header for the FR network, in the IP router 55, and is transmitted to the tunneling type ATM conversion node 351 using a non-ATM network point-to-point link, that is, an FR link. You.

Tunneling type ATM conversion node 351
Converts the IP packet provided with the layer 2 header for the non-ATM network point-to-point link, that is, the FR header, into the non-ATM network point-to-point link I / F.
In step 301, the packet is received, the FR header is added thereto, and the packet is transferred to the packet transfer unit 303.

The packet transfer unit 303 adds the AAL5 header used in the ATM network by the function of the tunneling processing unit 310 to the packet to which the FR header has been added, and then transmits the packet to the non-ATM network The ATM logical connection corresponding to the point-to-point link is obtained from the link correspondence table 304,
The data is transferred to the TM logical connection I / F 302. ATM
The logical connection I / F 302 transmits the packet to the AT
After being converted into M cells, it is transmitted to the IP router 352 capable of processing the FR header of the ATM logical connection obtained by the link correspondence table 304.

The packet converted into the ATM cell transmitted to the ATM logical connection is received by the ATM logical connection I / F 321 in the FR header processable IP router 352, and is converted from the ATM cell into a packet. The packet is transferred to the packet delivery unit 322. After deleting the AAL5 layer 2 header from the packet, the packet delivery unit 322 deletes the FR header by the function of the tunneling processing unit 326, and deletes the destination IP address of the packet.
The routing table 323 is searched based on the address, and the next destination is determined.

In this case, the delivery destination of the next stage is determined to be the FR router processable IP router 353 by this processing. If the delivery destination is not the connection described in the ATM logical connection management table 325 corresponding to the IP address, the packet delivery unit 322 attaches a header corresponding to the delivery destination and then sends the header to the IP router 353 capable of processing the FR header. To send to.

In order to transmit the packet to the next destination, the packet is sent to the ATM
The packet is transmitted to the logical connection I / F 321, and the ATM logical connection I / F 321 converts the packet into a cell, and transmits the cell to the FR header processable IP router 353. F that receives an ATM cell generated from the packet
The R-header-capable IP router 353 determines the next-stage delivery destination in the same manner as the FR-header-processable IP router 352, and then determines the next-stage delivery destination ATM logical connection as the IP address-compatible ATM logical connection management table 325. Since the packet is provided with an FR header by the function of the FR header processing unit 327, the function of the tunneling processing unit 326
After further adding an AAL5 header, the AAL5
ATM logical connection I /
After the ATM cell conversion in F321, the ATM network 50
To the tunneling type ATM conversion node 354 of FIG.

The cellized packet is received by the tunneling type ATM conversion node 354, and as shown in FIG. 29, is packetized by the ATM logical connection I / F 321 and then transferred to the packet transfer unit 303.

The packet transfer unit 303 converts the AAL5 header given to the packet into a tunneling processing unit 310.
ATM that the packet was received by the function
The non-ATM network point-to-point link corresponding to the logical connection
After obtaining the router 58, the data is transferred to the non-ATM network point-to-point link I / F 301.

According to the link correspondence table 304,
The packet is transmitted on the non-ATM network point-to-point link and transmitted to the IP router 58.

For example, if a non-ATM network is a frame relay (F
R) In the case of a network, the layer 2 header does not become a MAC header but becomes an FR header. In such a case, the MPOA method using LAN emulation that emulates a MAC address and a MAC header on an ATM network cannot be applied as it is. In this case, a MAC address is allocated to each non-ATM network point-to-point link, and an ELAN (Emulated LAN: virtual LAN realized by LAN emulation) is formed for each non-ATM network point-to-point link. In this case, ELANs are created for each non-ATM network point-to-point link, and BUS (Broadcast Un
known Server: Broadcast server for LAN emulation, LES (LAN Emulation Server: LA)
It is necessary to set the number of ELANs (servers for managing the ELAN participation terminals in N emulation) as many as the number of ELANs, so that network resources cannot be used efficiently.

As described above, a non-ATM network point-to-point link not operated by the MAC address is used for the ATM.
When the MPOA method is applied to a network having an interface of a conversion node, the ATM address of the egress MPC for shortcut delivery can be resolved, but the IP packet received from the ATM logical connection for shortcut is not It is not possible to determine what to deliver to the link or what header information to attach.

[Object of the Invention] Accordingly, an object of the present invention is to provide means for solving the above problems. The present invention provides means for dynamically connecting ATM conversion nodes having a non-ATM network point-to-point link as a non-ATM interface by a direct logical connection and setting a shortcut delivery path for bypassing a router on the ATM network. Is to give.

[0052]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and has one or more point-to-point links and one or more ATM links. A packet received from a two-point link is converted from a point-to-point link header of the packet to an ATM header and then converted to an ATM cell, and a predetermined ATM corresponding to the point-to-point link on a one-to-one basis. ATM on link
After transferring the ATM cells to the relay router network in the ATM network using the logical connection and converting the ATM cells received from the relay router network via the ATM logical connection on the ATM link into packets, the ATM header of the packet is used. Into a header for a point-to-point link,
In a packet transfer system having an ATM conversion node for transferring a point-to-point link corresponding to an M logical connection on a one-to-one basis, the ATM conversion node reads a destination of an IP packet received from the point-to-point link; Means for resolving an ATM address of an egress ATM conversion node which is an egress from the ATM network according to the destination, and a logical connection which bypasses the relay router network using the resolved ATM address.
Means for setting up to the TM conversion node and transmitting the packet to the egress ATM conversion node using the logical connection; and the egress ATM conversion node specifies a destination of the IP packet received from the logical connection bypassing the relay router network. Means for reading, means for selecting a corresponding point-to-point link according to the destination, means for transmitting the IP packet to the point-to-point link with a point-to-point link header corresponding to the destination And characterized in that:

Alternatively, it has one or more point-to-point links and one or more ATM links, attaches an ATM header to a packet received from the point-to-point link, and converts it into ATM cells. Then, by using a predetermined ATM logical connection on the ATM link corresponding to the point-to-point link on a one-to-one basis, the transfer is made to the relay router network in the ATM network, and from the relay router network on the ATM link. ATM
An ATM conversion node for converting an ATM cell received via a logical connection into a packet, deleting an ATM header of the packet, and transferring the ATM cell to a point-to-point link corresponding to the ATM logical connection on a one-to-one basis. In the packet transfer method, the ATM conversion node reads a destination of an IP packet received from the point-to-point link, and sets an AT in accordance with the destination.
Means for resolving an ATM address of an egress ATM conversion node which is an egress from the M network, and a logical connection for bypassing the relay router network is set up to the ATM conversion node using the resolved ATM address, and the logical connection is established. Means for transmitting the packet to the egress ATM conversion node using the egress ATM conversion node, the egress ATM conversion node using the IP received from the logical connection bypassing the transit router network.
Means for reading the destination of the packet, means for selecting a corresponding point-to-point link according to the destination,
Means for transmitting the IP packet to the point-to-point link with a point-to-point link header corresponding to the destination of the IP packet.

In the above packet transfer system, when the other ATM switching node notifies the relay router network of an ATM address in the address resolution means, an ATM logical connection corresponding to a point-to-point link addressed to the router is provided. It is characterized by using the notification.

More specifically, the packet transfer means of the present invention having a point-to-point link on a non-ATM network and setting up an ATM logical connection corresponding to the point-to-point link on the ATM network is , AT
A means (3 in FIG. 2) for reading a destination IP address of a packet delivered from a point-to-point link to an ATM logical connection at an ATM conversion node located between the M network and the non-ATM network, and bypassing the relay router network. Means for setting a path between the ATM conversion nodes (FIG. 2)
7 and 8) and means (6 and 8 in FIG. 2) for associating the destination IP address with the bypass path.

The means for handling a point-to-point link in which a plurality of logical channels are constructed on a physical link as a point-to-point link includes means having a frame relay (43 in FIG. 5).

Also, an ATM with a shortcut delivery function
Means having a hello function (5 in FIG. 2) for notifying the address of the conversion node to another ATM switching node is included.

Further, means (73 in FIG. 8) for the relay router network to notify the destination of the packet to be received at the egress ATM conversion node serving as the delivery destination of the shortcut ATM logical connection that bypasses the router on the ATM network; Means (41, 42, 43 in FIG. 5) for associating the destination with the link on the non-ATM side of the point-to-point link is included.

Further, it includes means (85 in FIG. 12) for notifying information to be associated with the link on the non-ATM side from the relay router network side. Also, it includes means (80, 81 in FIG. 12) for negotiating a link identifier in advance for notification from the relay router network side.

Further, when the egress ATM address conversion node notifies the relay router network of the ATM address of the node, communication is performed using an ATM logical connection corresponding to a point-to-point link on a non-ATM network ( 8) of FIG.

[Operation] According to the present invention, an ATM conversion node having a non-ATM network point-to-point link as a non-ATM interface is dynamically connected directly by a logical connection, and a shortcut delivery path for bypassing a router on the ATM network is provided. A system for setting can be realized.

That is, in the ATM conversion node, a function of reading the destination IP address is added, and a control packet that enables the point-to-point link of the non-ATM network corresponding to the IP address to be specified is received from the router network.
Alternatively, by receiving a control packet describing layer 2 header information for a point-to-point link including information on a point-to-point link of a non-ATM network, a transfer destination point of an IP packet from an ATM logical connection for shortcut delivery. A two-point link and a layer 2 header to be added can be obtained.

The entry ATM conversion node is a non-AT
ATM when the packet is transferred from the router of M network
ATM conversion node that bridges to the network
The M conversion node is an ATM conversion node for bridging a non-ATM network on the destination side of a previous packet, and the relay router is a router including a normal IP router or an IP router with an address resolution function. The network refers to a delivery route net between IP routers or between IP routers having an address resolution function in an ATM network.

[0064]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] Next, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1A shows an example of a network configuration diagram of the system of the present embodiment.

The ATM network 50 is a network configured by connecting a plurality of ATM switches and nodes having an ATM interface (I / F) by an ATM link.

The ATM network 50 includes an IP router 52 with an address resolution function having an IP packet routing function and an address resolution function, an IP router 53 with an address resolution function, a header conversion type ATM conversion node 151 with a shortcut delivery function, ATM conversion node 154 with header conversion type with shortcut delivery function is AT
They are connected by M link. Usually, the ATM network 5
In FIG. 25A, a number of IP routers, public network switches, and the like are connected by optical fibers or twisted pair wires.
FIG. 2 shows only the parts related to the present embodiment.

The header conversion type ATM conversion nodes 51 and 54 with the shortcut delivery function are connected to the ATM network 50 and A
The IP router 55 is connected by a TM link and is connected to a digital leased line such as DS1 or DS3 or a point-to-point link such as a frame relay (FR), a PPP link or xDSL (hereinafter referred to as a non-ATM network point-to-point link). , 56, 57 and IP routers 58, 59, 60.

FIG. 1B shows a link configuration in the above network. The header conversion type ATM conversion node 51 with the shortcut delivery function is provided with an A corresponding to a non-ATM network point-to-point link with the IP router 55.
The TM logical connection (VCC) is set up to the IP router 52 with the address resolution function. Similarly, the header conversion type ATM conversion node 51 with the shortcut delivery function
Sets up an ATM logical connection corresponding to a non-ATM network point-to-point link with the IP routers 56 and 57 up to the IP router 52 with the address resolution function. Similarly, the header conversion type ATM conversion node 54 with the shortcut delivery function also converts an ATM logical connection (VCC) corresponding to a non-ATM network point-to-point link with the IP routers 58, 59, 60 into an IP with an address resolution function. Set up to the router 53. Also, an IP router 52 with an address resolution function and an I router with an address resolution function
An ATM logical connection (VC
C) is set for data communication.

Here, the IP routers 59 and 60 and the header conversion type ATM conversion node 54 with the shortcut delivery function are provided.
, A plurality of logical point-to-point links are set on one physical channel, and these logical point-to-point links are treated in the same manner as other physical point-to-point links.

The header conversion type ATM conversion nodes 51 and 54 with the shortcut delivery function are the header conversion type ATM conversion nodes 51 and 5 with the shortcut delivery function.
4 has a function of uniquely allocating a link identifier (link ID) of a non-ATM network point-to-point link, thereby managing which link the non-ATM side IP router corresponds to. Further, the network of FIG. 1 includes a standard IP packet transfer unit and a shortcut transfer unit.

For example, in the standard IP packet transfer means, the IP packet delivered from the IP router 57 to the IP router 58
The P packet is transferred to the IP router 52 with an address resolution function via a point-to-point link via a header conversion type ATM conversion node 51 with a shortcut delivery function.
Using an M logical connection (VCC), the IP packet is transferred to the IP router 53 with the address resolution function. This is because the IP router 52 with the address resolution function
This is because when the ATM logical connection (VCC) is set, the IP router 53 with the address resolution function stores its own address and the linked address in the routing table. In this regard, the IP router 53 with the address resolution function also has a routing table for connection.

The IP router 53 with the address resolution function transfers the IP packet to the IP router 58 using a point-to-point link via the header conversion type ATM conversion node 54 with the shortcut delivery function.

On the other hand, the IP packet delivered from the IP router 57 to the IP router 58 is sent to the shortcut V by the shortcut conversion means in the header conversion type ATM conversion node 51 with the shortcut delivery function.
The packet is transferred to a header conversion type ATM conversion node 54 with a shortcut delivery function via a CC (ATM logical connection for shortcut delivery) 61 and transferred to an IP router 58 via a non-ATM side point-to-point link.

FIG. 2 shows the internal configuration of the header conversion type ATM conversion nodes 51 and 54 with the shortcut delivery function in FIG.

Referring to FIG. 2, header conversion type ATM conversion nodes 51 and 54 with a shortcut delivery function are
(A) Packet transmission / reception with a non-ATM network point-to-point link and management of the non-ATM network point-to-point link
F1 and (b) an ATM logical connection I / F2 for transmitting / receiving a packet to / from the ATM logical connection (VCC), converting the packet into ATM cells, packetizing the ATM cells, and setting and managing the ATM logical connection (VCC).
(C) a shortcut packet receiving unit 9 for receiving a shortcut packet, (d) a shortcut packet transmitting unit 7 for transmitting a shortcut packet, and (e).
A destination reading function for performing a packet transfer process between the non-ATM network point-to-point link I / F1 and the ATM logical connection I / F2, the shortcut transmitting unit 7 and the shortcut packet receiving unit 9, and a process of reading a destination IP address of the packet. Attached packet transfer unit 3
(F) a link correspondence table 4 for holding a link correspondence between the non-ATM network point-to-point link I / F1 and the ATM logical connection link I / F2, and a link ID; and (g) the shortcut transmission unit. And (h) information for transmitting a packet received by the shortcut receiving unit 9 to the non-ATM network point-to-point link I / F1. A point-to-point exit cache 8 that holds
(I) Shortcut ATM logical connection (VC
C) Address resolution response processing unit 5 with a hello function for making an address resolution request and address resolution response
And (j) a header conversion processing unit 10 for converting between a layer 2 header used on a non-ATM network point-to-point link and an AAL5 header used on an ATM logical connection.

FIG. 3 is a block diagram of the IP with the address resolution function of FIG.
3 shows an internal configuration of the routers 52 and 53. FIG.
With reference to FIG.
53 denotes (i) packet transmission / reception with the ATM network 50, AT
AT for setting and managing M logical connection (VCC)
M logical connection (VCC) I / F 21, (ii) a routing table 23 describing to which node the destination IP address should be delivered, and (iii) a packet received from the ATM logical connection (VCC) I / F 21. With reference to the routing table 23,
A destination link is determined, and a control packet for address resolution is sent to an address resolution processing unit 24 with a hello function,
An M logical connection (VCC) I / F 21 for exchanging a packet with a packet delivery unit 22;
IP address correspondence logical connection management table 25 that manages whether it corresponds to a TM logical connection (VCC)
And (v) an address solution processing unit 24 with a hello function for processing a control packet received from the packet delivery unit 21 and setting and managing the IP address correspondence logical connection management table 25.

FIG. 4 is a diagram showing the contents of the point-to-point entry cache 6 in the header conversion type ATM conversion nodes 51 and 54 with the shortcut delivery function of FIG. Point-to-point entrance cache 6
It comprises a cache capable of a data holding function for holding data at a high speed, and in order to indicate from which point-to-point link the IP packet to be changed and transferred is transferred, a header conversion type ATM conversion node 51 with a shortcut delivery function, A field 31 for storing a point-to-point link ID allocated for uniquely determining a point-to-point link in 54;
A field 32 for storing a destination IP address of an IP packet to be shortcutted, a field 33 for storing a destination ATM address used when setting a shortcut VCC connection, and a shortcut VCCID for identifying the shortcut VCC connection
Is stored in the field 34.

FIG. 5A shows the header conversion type ATM conversion nodes 51 and 5 with the shortcut delivery function shown in FIG.
4 is a diagram showing the contents of a point-to-point exit cache 8 in FIG. The point-to-point exit cache 8 comprises a cache capable of a data holding function for holding data at a high speed, a field 41 for storing a destination IP address of a packet delivered from the shortcut VCC connection, and a field 41 received from the shortcut VCC connection. A field 42 for storing a point-to-point link ID for determining to which non-ATM side point-to-point link the packet having the destination IP address is to be transferred, and a packet when transferring to the non-ATM side point-to-point link And a field 43 for storing non-ATM side link information for storing data required for header information and the like added to the data.

FIG. 5B shows the header conversion type ATM conversion nodes 51 and 5 with the shortcut delivery function shown in FIG.
FIG. 8 is a diagram showing the contents of another embodiment of the point-to-point exit cache 8 in FIG. FIG. 5 (a)
The difference from the above is the contents of a field 43 for storing non-ATM side link information. In this field, a layer 2 header used on a non-ATM network, such as an FR header, to be created in advance by the header conversion processing unit 4 (Non-ATM
(When the network is an FR network). For this reason, FIG.
According to (b), after searching the contents of the non-ATM side link information field 43 in the case of FIG. 5A, it is possible to omit the process of creating the layer 2 header.

Next, the operation of the packet transfer means of the present invention will be described. In the standard IP packet transfer means shown in FIG. a. a. The first IP packet is sent from the IP router 57 via the header conversion type ATM conversion node 51 with the shortcut delivery function to the IP router 52 with the address resolution function and the IP router with the address resolution function.
Is transferred to the router 53 and is transferred from the IP router 53 with the address resolution function to the header conversion type A with the shortcut delivery function.
The following describes the shortcut transfer means when the packet is delivered to the IP router 58 via the TM conversion node 54.

FIG. 6 shows that the IP routers 57 to
8 is a conceptual diagram of a route in the case where an IP packet is transmitted to shortcut number 8 via shortcut VCC 61. FIG.

First, from the link ID = 3, the header conversion type ATM conversion node 51 with the shortcut delivery function
A packet is transmitted, and the field state of the point-to-point entry cache 6 and the field state of the point-to-point exit cache 8 in the header conversion type ATM conversion node 51 with the shortcut delivery function are shown. The IP packet passes through the header conversion type ATM conversion node 54 with the shortcut delivery function and passes through the IP router 5 having the link ID = 1.
8 shows an example.

As shown in FIG. 6, the header conversion type ATM conversion nodes 51 and 54 with the shortcut delivery function are non-A
A link ID that can be uniquely identified within the node is assigned to each point of the TM network point-to-point link. Destination IP address a. a. a. The non-ATM network point-to-point link I / F1 receiving the packet No. 1 is transferred to the packet transfer unit 3 having a destination reading function. The packet transfer unit 3 with the destination reading function transmits the destination address a. a. a. 1 to check whether the corresponding shortcut transfer entry exists in the point-to-point entry cache 6.

If there is no corresponding entry in the point-to-point entry cache 6, it is determined whether the setting of the shortcut VCC is necessary. If it is not necessary, the ATM logical connection I corresponding to the table of the link correspondence table 4 is determined. / F2 is transmitted to the ATM side link.

On the other hand, when the packet transfer unit 3 with the destination reading function finds the corresponding entry in the point-to-point entry cache 6, it checks whether or not the shortcut VCC connection of the corresponding entry is set, and the setting is made. In this case, the IP packet is transferred to the shortcut packet transmitting unit 7 by designating the shortcut VCC corresponding to the corresponding entry in the point-to-point entry cache 6. The packet transfer unit 3 having the destination reading function finds the corresponding entry in the point-to-point entry cache 6 and executes the shortcut VCC.
If has not been set yet, the IP packet is transferred to the ATM side link of the ATM logical connection I / F2 according to the table of the link correspondence table 4. If the packet transfer unit 3 with the destination reading function determines that there is no corresponding entry of the IP packet in the point-to-point entry cache 6 and it is necessary to set a shortcut VCC, the shortcut to the node having the destination address of the IP packet is performed. In order to acquire the setting destination information of the VCC, the address resolution responding unit 5 with the hello function is notified to perform the address resolution processing. After giving the notification,
The IP packet is transferred to a link on the ATM side of the ATM logical connection I / F2 according to the table of the link correspondence table 4.

Next, the address resolution processing will be described with reference to FIGS. 8, 9 and 10. FIG. 8 shows a header conversion type ATM switching node 51 with a shortcut delivery function.
5 is a flowchart of an address resolution process showing a transmission relationship among the IP router 52 with an address resolution function, the IP router 53 with an address resolution function, and a header conversion type ATM switching node 54 with a shortcut delivery function.

First, the header conversion type ATM conversion node 51 with the shortcut delivery function performs the process 70 according to the flowchart of FIG. The creation of a shortcut is determined (700 in FIG. 9), an entry in the point-to-point entry cache 6 is created (701 in FIG. 9), and 3 which is the distributed link ID of the packet for which the shortcut transfer is to be performed to the entry. A. Destination IP address of the IP packet a. a. Write 1 (70 in FIG. 9).
2). Thereafter, the address resolution request control packet is generated by the address resolution response processing unit 5 with the hello function in the header conversion type ATM conversion node 51 with the shortcut delivery function, and the point having the same link ID on the ATM logical connection I / F2 is generated. The control packet is transmitted on the two-point link, and the process 70 ends (see 7 in FIG. 9).
03).

The address resolution request (71 in FIG. 8) transferred by the process 70 is sent to the IP with the address resolution function.
The packet transfer unit 2 with the destination reading function is received from the ATM logical connection I / F 21 and received by the router 52 within the IP router 52 with the address resolution function.
2 and is an address resolution control packet,
It is transferred to the address resolution processing unit 24 with the hello function.
The address resolution processing unit 24 with the hello function writes the identifier of the link from which the packet was transmitted to the ATM logical connection management table 25 corresponding to the IP address, and distributes the packet to transfer the address resolution control packet to the next router. Return to section 22. Packet distribution unit 2
2 transfers the address resolution request control packet (72 in FIG. 8) to the ATM logical connection (VCC) of the ATM logical connection I / F 21 to be transmitted according to the routing table 23.

Next, the IP router with address resolution function 53 that has received the address resolution request control packet 72
Is determined in the IP address corresponding ATM logical connection management table 25 when the address resolution destination is determined to be the subordinate header conversion type ATM conversion node 54 with the shortcut distribution function by the processing of the address resolution processing unit 24 with the hello function. The cache generation request 73 is transmitted to the point-to-point link having the link identifier. The header conversion type ATM conversion node 54 that has received the cache generation request packet 73 starts processing 74.

FIG. 10 shows a flowchart of the process 74. In the ATM logical connection I / F2,
The ATM conversion node with shortcut delivery function 54 that has received the cache generation request 73 stores the link ID of the link that received the packet (740 in FIG. 10),
It is determined whether there is a resource for the shortcut (741 in FIG. 10). If the cache resource cannot be secured, a cache creation response indicating a cache creation failure is returned (744 in FIG. 10). If the resource can be secured, the stored link ID and the destination described in the cache creation request are returned. The IP address and the non-ATM side link information are written in the point-to-point exit cache 8 (742 in FIG. 10), and the cache generation response packet 75 indicating successful cache generation is included in the AT of the own node.
The M address is described and returned to the IP router 53 with the address resolution function using the point-to-point link on the ATM side, and the process 74 ends (743 in FIG. 10).

The IP router with address resolution function 53 that has received the cache generation response packet 75 describes the ATM address and the like described in the cache generation response in the address resolution response 76 and sends it to the IP router 52 with address resolution function. The IP router with address resolution function 52 refers to the contents of the ATM logical connection management table 25 corresponding to the point-to-point link for the address resolution response 76 and converts the address resolution response 77 to the header conversion type ATM conversion with shortcut delivery function. Transfer to node 51. Header conversion type ATM conversion node 51 with a shortcut delivery function receiving the address resolution response 77
Starts the process 78.

FIG. 11 shows a flowchart of the process 78. At 780 in FIG. 11, upon receiving the address resolution response, the header conversion type ATM conversion node with shortcut delivery function 51 confirms the success or failure of the shortcut described in the address resolution response (781 in FIG. 11). The ATM address described in the address resolution response is written into the corresponding entry of the point-to-point entry cache 6 (782 in FIG. 11), and the setting of the shortcut VCC for the ATM address is started (783 in FIG. 11). . If a response indicating a shortcut failure is received due to shortage of shortcut resources, the process waits for a certain period of time, and then transmits an address resolution request to the IP router 52 with the address resolution function again (784 in FIG. 11).

As shown in FIG. 7, it is determined whether the header conversion type ATM conversion node with the shortcut delivery function and the IP router with the address resolution function have the shortcut delivery function and the address resolution processing function. To do this, an address resolution response processing unit with a hello function in the header conversion type ATM conversion node with a shortcut delivery function (5 in FIG. 2) and an address resolution processing unit with a hello function in the IP router with the address resolution function (24 in FIG. 3) ) Has a function of recognizing each other by exchanging hello messages at the start of each address resolution process or at the start of a node.

More specifically, FIG. 7A shows a header conversion type ATM conversion node 5 with a shortcut delivery function.
2 through the ATM logical connection I / F (2 in FIG. 2) from the address resolution response processing unit with the hello function (5 in FIG. 2).
The address resolution processing unit with the hello function (2 in FIG. 3) is connected via the 53 ATM logical connection I / F (21 in FIG. 3).
In step 4), the hello message 65 is transferred, and in response to the transfer, the hello message 66 is transferred from the IP routers 52, 53 having the address resolution function to the header conversion type ATM conversion nodes 51, 54 having the shortcut delivery function. Similarly, FIG. 7 (b) shows the hello message 6 from the IP routers 52 and 53 with the address resolution function to the header conversion type ATM conversion nodes 51 and 54 with the shortcut delivery function.
7 is transferred, and in response thereto, a hello message 68 is transferred from the header conversion type ATM conversion nodes 51 and 54 with the shortcut delivery function to the IP routers 52 and 53 with the address resolution function. This hello message is exchanged after the point-to-point entry cache 6 and exit cache 8 have been rewritten by the end of the process 78 shown in FIG. 8, thereby enabling mutual exchange of information. Is no longer necessary.

Note that this function can be replaced by a means in which the header conversion type ATM conversion node with the shortcut delivery function and the IP router with the address resolution function hold each other's address table.

After each of the above-described processes is executed for a short time, the following operation process is performed.

After the shortcut VCC is set, the destination IP address a. a. a. The packet No. 1 is delivered on the shortcut VCC61. This state will be described with reference to FIG. The link ID is assigned to the point-to-point link of the IP router 57 in FIG.
= 3 is set, and packets arriving at the non-ATM network point-to-point link I / F1 of the ATM conversion node 51 via the point-to-point link are sent to the point-to-point entry cache 6 in the packet delivery unit 3 of FIG. Of the packet, and checks the destination IP address of the packet.
When the destination IP address matches the destination IP address field 32 of the point-to-point entry cache 6, the shortcut VCC indicated in the shortcut VCCID field 34 of the entry is not required by the shortcut packet transmitting unit 7 in FIG. It is transferred after removing the header part.

By the above processing, the shortcut VCC6
1 is received by the shortcut packet receiving unit (9 in FIG. 2) of the header conversion type ATM conversion node 54 with the header delivery function with the shortcut delivery function, and refers to the point-to-point exit cache 8 and Destination IP address of packet 62 a. a.
a. The point-to-point link ID and non-ATM side link information corresponding to No. 1 are acquired. Based on the above information,
The packet transfer unit 3 with the destination reading function has the link ID =
After constructing the header necessary for the point-to-point link of No. 1, the port =
1 to the IP router 58 with link ID = 1,
The IP packet is transferred.

In the first embodiment of the present invention, a shortcut delivery system of an MPOA system that recognizes each other by a MAC address in a LAN emulation environment is described by introducing a link ID to an ATM logical connection corresponding to a point-to-point link. By distributing the control packet to the network, it can be realized in a point-to-point link environment. That is, it is possible to avoid the processing bottleneck of the router in the point-to-point link environment.

[Second Embodiment] Next, a second embodiment of the present invention will be described. The network configuration used in the present embodiment is the same as that in FIG. 1, and the configurations of header conversion type ATM switching nodes 51 and 54 with a shortcut delivery function and IP routers 52 and 53 with an address resolution function are also shown in FIG.
This is almost the same as the configuration shown in FIG.

FIG. 12 shows a header conversion type ATM switching node 51 with a shortcut delivery function, an IP router 52 with an address resolution function, an IP router 53 with an address resolution function, and a header conversion type ATM with a shortcut delivery function.
6 is a flowchart of an address resolution process showing a transmission relationship with a switching node.

As shown in FIG. 12, a link I between the header conversion type ATM conversion nodes 51 and 54 with the shortcut delivery function and the IP routers 52 and 53 with the address conversion function is provided.
D information is exchanged to link IDs used in the header conversion type ATM conversion nodes 51 and 54 with the shortcut delivery function and IP routers 52 and 53 with the address resolution function.
When the processes 80 and 81 for associating are added to the link identifier of the above, the control packet can be exchanged on another control ATM logical connection (VCC) without transferring the control packet on the point-to-point link. Become.

The difference from the processing in FIG. 8 is that each control packet is exchanged on a control ATM logical connection (VCC), and link ID information is added to each control packet.

First, the link ID used in the header conversion type ATM conversion nodes 51 and 54 with the shortcut delivery function and the IP router 52 with the address resolution function are set in advance.
Point-to-point link ID negotiation (Link ID = A, Link I
The processing 80 and 81 of (D = B) are performed. Specifically, in processes 80 and 81, if the link ID is stored in the point-to-point entry cache 6 and the exit cache 8, and the link identifier is stored in the logical connection management table 25 corresponding to the IP address, the necessary It becomes a search target at the time of search and can contribute to quick routing processing.

Next, the header conversion type ATM conversion node 51 with the shortcut delivery function performs processing 82 shown in FIG.
Execute In FIG. 13, the header conversion type ATM conversion node 51 with the shortcut delivery function decides to create a shortcut (820 in FIG. 13), creates an entry in the entrance cache 6 (821 in FIG. 13), and stores a link ID and Cache writing of the destination IP address is performed (822 in FIG. 13). Subsequently, the control packet A
An address resolution request (dest IP = X, Link ID = A) is transmitted to the ATM logical connection VCC of the TM link (FIG. 13)
823).

The address resolution request (83 in FIG. 12) transferred by the process 82 is transmitted to the I with the address resolution function.
The packet is received by the P router 52 and is transmitted from the ATM logical connection I / F 21 to the packet delivery unit 22 with the destination reading function inside the IP router 52 with the address resolution function. Is forwarded to The address resolution processing unit 24 with the hello function converts the identifier of the link from which the packet was transmitted to the IP address corresponding AT.
The data is written into the M logical connection management table 25 and returned to the packet delivery unit 22 to transfer the address resolution control packet to the next router. According to the routing table 23, the packet delivery unit 22 transfers the address resolution request control packet (dest IP = X) (84 in FIG. 12) to the ATM logical connection VCC of the ATM logical connection I / F 21 to be transmitted.

Next, the IP router with address resolution function 53 that has received the address resolution request control packet 84
When the address resolution processing unit 24 with the hello function determines that the address resolution destination is the subordinate ATM conversion node 54 with the shortcut distribution function, the link identifier described in the IP address-compatible ATM logical connection management table 25 is changed. Generation request 85 (dest IP = X, Lin
k ID = B). The cache generation request packet 8
5, the header conversion type ATM conversion node 54 with the shortcut delivery function that has received 5 starts processing 86.

FIG. 14 shows a flowchart of the process 86. In the ATM logical connection I / F2,
Upon receiving the cache generation request 85, the header conversion type ATM conversion node 54 with the shortcut delivery function stores the link ID of the link that received the packet (FIG. 14).
860), it is determined whether there is a resource for the shortcut (861 in FIG. 14). If the cache resource cannot be secured, an address resolution response indicating the cache generation failure is transmitted to the control packet ATM logical connection (864 in FIG. 14). If the resource can be secured, the address is described in the cache generation packet. The link ID of the link, the destination IP address described in the cache generation request, and the non-ATM side link information are written in the point-to-point exit cache 8 (FIG. 14).
862), the ATM address of the own node is described in the cache generation response packet 87 indicating the cache generation success (dest IP = X, Link ID = B, ATM = Y), and the ATM side point-to-point link is used. A reply is sent to the IP router 53 with the address resolution function, and the process 86 is terminated (FIG. 14
863).

The IP router with address resolution function 53 that has received the cache generation response 87 writes the ATM address and the like described in the cache generation response in the address resolution response 88 (dest IP = X, ATM = Y). Is transferred to the IP router 52 with the address resolution function, and the IP router 52 with the address resolution function refers to the contents of the ATM logical connection management table 25 corresponding to the IP address by referring to the address resolution response 89 (dest IP address). = X, ATM
= Y, Link ID = A) to the header conversion type ATM conversion node 51 with the shortcut delivery function. Upon receiving the address resolution response 89, the header conversion type ATM conversion node 51 with a shortcut delivery function starts processing 90.

FIG. 15 shows a flowchart of the process 90. In the process 900 of FIG. 15, the header conversion type AT with the shortcut delivery function that has received the address resolution response
The M conversion node 51 confirms the success or failure of the shortcut described in the address resolution response (901 in FIG. 15), and if successful, stores the ATM address and the link ID in the address resolution response in the point-to-point entry cache 6
(902 in FIG. 15), and the AT
The setting of the shortcut VCC for the M address is started (903 in FIG. 15). If a response indicating shortcut failure is received due to shortage of shortcut resources, the process waits for a certain period of time, and then transmits an address resolution request to the IP router with address resolution function 52 again (904 in FIG. 14).

After the shortcut VCC is set, the packet of the destination IP address
It will be delivered on CC61.

According to the second embodiment of the present invention, in addition to the effect of the first embodiment, the control packet can be delivered on another ATM logical connection (VCC).
A load is applied to the IP packet transfer processing of the standard transfer because there is no need to determine a control packet and a packet delivered on the ATM logical connection (VCC) without infringing the bandwidth of the TM logical connection (VCC). There is also an effect that there is no.

[Third Embodiment] Next, a third embodiment of the present invention will be described in detail with reference to the drawings. FIG.
FIG. 6A shows an example of a network configuration diagram of the system of the present embodiment. The ATM network 50 includes a plurality of ATMs.
This is a network configured by connecting an exchange and a node having an ATM interface (I / F) by an ATM link.

In the ATM network 50, the FR header-processable IP routers 252 and 253 having an address resolution function having an IP packet routing function, an address resolution function, and a FR header processing function, and a tunneling type ATM conversion with a shortcut delivery function are provided. The node 251 and a tunneling type ATM conversion node 254 with a shortcut delivery function are connected by an ATM link.

The tunneling type ATM conversion nodes 251 and 254 with the shortcut delivery function are connected to the ATM network 5
0 and an ATM link, DS1, DS3 and other digital dedicated lines, frame relay, PPP link,
By using a point-to-point link such as xDSL (hereinafter referred to as a non-ATM network point-to-point link), the IP routers 55, 56, 57 and
8, 59, 60.

FIG. 16B shows a link configuration in the above network. The tunneling type ATM conversion node 251 with the shortcut delivery function is connected to the IP router 55.
An ATM logical connection corresponding to a non-ATM network point-to-point link between
The setting is made up to the IP router 252 capable of processing the R header. Similarly, the tunneling type AT with the shortcut delivery function
The M conversion node 251 communicates with the IP routers 56 and 57 with a non-A
The ATM logical connection corresponding to the TM network point-to-point link is set up to the FR router processable IP router 252 with the address resolution function. Similarly, the tunneling type ATM conversion node 254 with the shortcut delivery function has the A corresponding to the non-ATM network point-to-point link with the IP routers 58, 59 and 60.
The TM logical connection is set up to the IP router 253 capable of processing the FR header with the address resolution function. Also, an IP router 252 capable of processing an FR header with an address resolution function.
The ATM logical connection VCC is also set between the router and the IP router 253 capable of processing an FR header with an address resolution function for data communication.

Here, the IP routers 59 and 60 and the tunneling type ATM conversion node 2 with the shortcut delivery function are used.
Although a plurality of logical point-to-point links are set on one physical channel as between 54, these logical point-to-point links are treated similarly to other physical point-to-point links.

The tunneling type ATM conversion nodes 251 and 254 with the shortcut delivery function uniquely identify the link identifier (link ID) of the non-ATM network point-to-point link of the tunneling type ATM conversion nodes 251 and 254 with the shortcut delivery function. It has an allocation function, which manages which link the non-ATM side IP router corresponds to.

Further, in the network shown in FIG.
It has standard IP packet transfer means and shortcut transfer means.

For example, in the standard IP packet transfer means, the IP packet delivered from the IP router 57 to the IP router 58
The P packet is transferred to the FR header-capable IP router 252 with address resolution function via the point-to-point link via the tunneling type ATM conversion node 251 with shortcut delivery function, and the FR header-capable IP router 252 with address resolution function. Uses the ATM logical connection VCC to convert the IP packet into an IP router 253 capable of processing an FR header with an address resolution function.
Transfer to This is because the FR header-capable IP router 252 with address resolution function stores its own address and the address linked to the FR header-capable IP router 252 with address resolution function in the routing table in advance when setting up the ATM logical connection. Because they do. In this regard, the IP router 253 capable of processing the FR header with the address resolution function similarly has a routing table for connection.

The IP router 253 capable of processing the FR header with the address resolution function transmits the IP packet to the IP router using a point-to-point link via a tunneling type ATM conversion node 254 with a shortcut delivery function.
Transfer to router 58.

On the other hand, the IP packet delivered from the IP router 57 to the IP router 58 is sent to the tunneling type ATM conversion node 251 with the shortcut delivery function via the shortcut VCC 261 by the shortcut delivery means. The packet is transferred to the tunneling type ATM conversion node 254 and transferred to the IP router 58 via the non-ATM side point-to-point link.

FIG. 17 shows a tunneling type ATM conversion node 251 with a shortcut delivery function in FIG.
254 shows the internal configuration.

Referring to FIG. 17, tunneling type ATM conversion nodes 251 and 25 with a shortcut delivery function are provided.
Reference numeral 4 denotes (a) a non-ATM network point-to-point link I / F 201 for transmitting / receiving packets to / from a non-ATM network point-to-point link and managing the non-ATM network point-to-point link; and (b) a packet to an ATM logical connection. ATM logical connection I / F 202 for performing transmission / reception, packetization of ATM cells, packetization of ATM cells, and setting / management of ATM logical connection, (c) shortcut packet receiving unit 209 for receiving a shortcut packet, and (d) shortcut (E) a shortcut packet transmitting unit 207 for transmitting a packet;
The non-ATM network point-to-point link I / F1, ATM logical connection I / F202, shortcut transmitting unit 207 and shortcut packet receiving unit 20
9, a packet transfer unit 203 having a destination reading function for performing a packet transfer process and a process of reading a destination IP address of the packet; (f) the non-ATM network point-to-point link I / F 201 and the ATM logical connection link I / F; A link correspondence table 204 for holding a link correspondence and a link ID between F202, (g) a point-to-point entry cache 206 for holding information of a packet to be transferred to the shortcut transmitting unit 207, and (h) a shortcut. A point-to-point exit cache 208 holding information for transmitting a packet received by the receiving unit 209 to the non-ATM network point-to-point link I / F 201; (i)
An address resolution response processing unit 205 with a hello function for performing an address resolution request and an address resolution response for creating a shortcut VCC, and (j) a packet received from a non-ATM network point-to-point link,
A tunneling processing unit 210 for attaching an L5 header or deleting an AAL5 header of a packet arriving from an ATM logical connection to realize a tunneling process.
And

FIG. 18 shows the internal configuration of the IP routers 252 and 253 capable of processing the FR header with the address resolution function shown in FIG.

Referring to FIG. 18, the IP routers 252 and 253 capable of processing the FR header with the address resolution function
(I) an ATM logical connection I / F 221 for transmitting / receiving packets to / from the ATM network 50 and setting / managing an ATM logical connection (VCC); and (ii) a routing table describing to which node the destination IP address should be delivered. 223, and (iii) a packet received from the ATM logical connection I / F 221 with reference to the routing table 223 to determine a delivery destination link, and a control packet for address resolution to an address resolution processing unit 224 with a hello function. , ATM logical connection I /
(Iv) a packet delivery unit 222 for communicating with F21
An IP address correspondence logical connection management table 225 for managing which ATM logical connection the IP address corresponds to, and (v) processing of a control packet received from the packet delivery unit 221 and the IP address correspondence logical connection management table 225. An address resolution processing unit 224 with a hello function for performing setting and management;
i) FR header processing unit 2 that performs FR header generation processing
27 and (vii) AA is further added to the packet attached to the FR header.
Add L5 header or delete AAL5 header to
And a tunneling processing unit 227 that enables the FR header processing unit 227 to process the packet with the R header.

FIG. 19 is a conceptual view of a route when an IP packet is transmitted from the IP router 57 to the IP router 58 via the shortcut VCC 261.
2, 23, and 24 are diagrams showing the address resolution processing corresponding to FIGS. 8, 9, 10, and 11 of the first embodiment.

The third embodiment is different from the first embodiment in that the IP routers 252 and 253 capable of processing an FR header with an address resolution function have an FR header generation function. The point where the FR header generated by the FR header processing unit (227 in FIG. 18) of the IP router capable of processing the FR header with the function is transmitted, and the point-to-point held by the tunneling type ATM conversion nodes 251 and 254 with the shortcut delivery function are transmitted. The contents of the point exit cache 208 are shown in FIG.
The point shown in (b) is always formed.

In FIG. 21, the first signal shown in FIG.
The processing different from that of the embodiment is that the contents of the transfer 273 of the cache generation request control packet and the processing 274 by the tunneling type ATM conversion node 254 with the shortcut delivery function enable the FR header processing with the address resolution function to be performed.
The content of the cache generation response 275 to the P router 253 is different.

For example, upon receiving the address resolution request control packet 272, the FR router processable IP router 253 with the address resolution function, by the processing of the address resolution processing unit with the hello function 224, has a shortcut delivery function with a subordinate address resolution destination. If it is determined that the node is the tunneling type ATM conversion node 254, a cache generation request (dest IP = X, FR header ゛ = M) is issued to the point-to-point link having the link identifier described in the IP address corresponding ATM logical connection management table 225. ) 2
Send 73. The cache generation request packet 273
Received, the tunneling type ATM conversion node 254 with the shortcut delivery function starts the process 274.

Also, the processing 270 shown in FIG. 22, the processing 274 shown in FIG. 23, and the processing 278 shown in FIG.
The processes are the same as the processes 70, 74 and 78 shown in the first embodiment, and the exchange of the hello message shown in FIG. 20 is the same as that in FIG.

In the third embodiment of the present invention, a shortcut delivery system of an MPOA system that recognizes each other by a MAC address in a LAN emulation environment can be realized in a tunneling point-to-point link environment. That is, it is possible to avoid the processing bottleneck of the router in the point-to-point link environment.

[0133]

An advantage of the present invention is that a processing bottleneck of a router can be avoided even in a non-ATM network connected to an ATM network by a point-to-point link. The reason is that the route bypassing the router and the point-to-point link on the non-ATM network and the destination I
This is because having a correspondence table of P addresses makes it possible to bypass the router network.

[Brief description of the drawings]

FIG. 1A is a configuration diagram of a network system according to the present invention, and FIG. 1B is an explanatory diagram of links of the network system.

FIG. 2 is a block diagram showing an internal configuration of a header conversion type ATM conversion node with a shortcut delivery function of FIG. 1 according to the present invention.

FIG. 3 is an IP with an address resolution function of FIG. 1 according to the present invention;
FIG. 3 is a block diagram illustrating an internal configuration of a router.

FIG. 4 is a block diagram of a point-to-point entry cache of FIG. 2 according to the present invention;

FIG. 5 is a configuration diagram of a point-to-point exit cache of FIG. 2 according to the present invention;

FIG. 6 is an explanatory diagram of a router network bypass route according to the present invention.

FIG. 7 is an explanatory diagram of a halo function according to the present invention.

FIG. 8 is a flowchart of an address resolution process according to the present invention.

FIG. 9 is an internal flowchart of the process 70 of FIG. 8 according to the present invention.

FIG. 10 is an internal flowchart of the process 74 of FIG. 8 according to the present invention.

FIG. 11 is an internal flowchart of the process 78 of FIG. 8 according to the present invention.

FIG. 12 is a flowchart of an address resolution process according to the second embodiment of the present invention.

FIG. 13 is an internal flowchart of the process 82 of FIG. 12 according to the present invention.

FIG. 14 is an internal flowchart of the process 86 of FIG. 12 according to the present invention.

FIG. 15 is an internal flowchart of the process 90 of FIG. 12 according to the present invention.

16A is a configuration diagram of a network system according to a third embodiment of the present invention, and FIG. 16B is an explanatory diagram of links of the network system.

17 is a block diagram showing an internal configuration of a tunneling type ATM conversion node with a shortcut delivery function of FIG. 16 according to the present invention.

FIG. 18 is a block diagram showing the internal configuration of the FR header-capable IP router with address resolution function of FIG. 16 according to the present invention.

FIG. 19 is an explanatory diagram of a router network bypass route according to the third embodiment of the present invention.

FIG. 20 is an explanatory diagram of a halo function according to the third embodiment of the present invention.

FIG. 21 is a flowchart of an address resolution process according to the third embodiment of the present invention.

FIG. 22 is an internal flowchart of the process 270 of FIG. 21 according to the present invention.

FIG. 23 is an internal flowchart of the process 274 of FIG. 21 according to the present invention.

FIG. 24 is an internal flowchart of the process 278 of FIG. 21 according to the present invention.

FIG. 25A is a configuration diagram of a network system to which the present invention is applied, and FIG. 25B is an explanatory diagram of links of the network system.

FIG. 26 is a diagram illustrating a header conversion type A of FIG. 25 which is an object of the present invention;
It is a block diagram which shows the internal structure of a TM conversion node.

FIG. 27 is a block diagram showing the internal configuration of the IP router of FIG. 25 which is the object of the present invention.

FIG. 28A is a configuration diagram of a second network system to which the present invention is applied, and FIG. 28B is an explanatory diagram of links of the network system.

FIG. 29 shows the tunneling type ATM of FIG. 28 according to the present invention.
FIG. 3 is a block diagram illustrating an internal configuration of a conversion node.

FIG. 30 is a block diagram showing an internal configuration of an IP router capable of processing the FR header of FIG. 28 which is an object of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Non-ATM network point-to-point link I / F 2 ATM logical connection I / F 3 Packet transfer unit with destination reading function 4 Link correspondence table 5 Address resolution response processing unit with hello function 6 Point-to-point entrance cache 7 Shortcut packet transmission Unit 8 Point-to-point entrance cache 9 Shortcut packet receiving unit 10 Header conversion processing unit 21 ATM logical connection I / F 22 Packet distribution unit 23 Routing table 24 Address resolution processing unit with hello function 25 ATM logical connection management table corresponding to IP address 50 ATM network 51 Header conversion type ATM with shortcut delivery function
Conversion node 52 IP router with address resolution function 53 IP router with address resolution function 54 Header conversion type ATM with shortcut delivery function
Conversion nodes 55, 56, 57 IP routers 58, 59, 60 IP routers 61 Shortcut VCC 101 Non-ATM network point-to-point link I / F 102 ATM logical connection I / F 103 Packet transfer unit 104 Link correspondence table 110 Header conversion processing unit 121 ATM logical connection I / F 122 Packet distribution unit 123 Routing table 125 ATM logical connection management table corresponding to IP address 151 Header conversion type ATM conversion node 152 IP router 153 IP router 154 Header conversion type ATM conversion node 201 Non-ATM network point-to-point Link I / F 202 ATM logical connection I / F 203 Packet transfer unit with destination reading function 204 Link correspondence table 205 A with hello function Response solution processing unit 206 Point-to-point entry cache 207 Shortcut packet transmission unit 208 Point-to-point entry cache 209 Shortcut packet reception unit 210 Tunneling processing unit 221 ATM logical connection I / F 222 Packet distribution unit 223 Routing table 224 Hello function Address resolution processing unit 225 IP address corresponding ATM logical connection management table 226 Tunneling processing unit 227 FR header processing unit 251 Tunneling type A with shortcut delivery function
TM conversion node 252 FR header processable IP with address resolution function
Router 253 IP address capable of processing FR header with address resolution function
Router 254 Tunneling type A with shortcut delivery function
TM conversion node 261 Shortcut VCC 301 Non-ATM network point-to-point link I / F 302 ATM logical connection I / F 303 Packet transfer unit 304 Link correspondence table 310 Tunneling processing unit 321 ATM logical connection I / F 322 Packet delivery unit 323 Routing table 325 ATM logical connection management table corresponding to IP address 326 Tunneling processing unit 327 FR header processing unit 351 Tunneling type ATM conversion node 352 FR header processing enabled IP router 353 FR header processing enabled IP router 354 Tunneling type ATM conversion node

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04L 12/28 H04L 12/46 H04L 12/66

Claims (20)

(57) [Claims] Claims 1. A packet having one or more point-to-point links and one or more ATM links and receiving packets from the point-to-point link.
The header for the point-to-point link of the packet is A
After conversion to a TM header, the cell is converted to an ATM cell and transferred to a relay router network in the ATM network using a predetermined ATM logical connection on the ATM link corresponding to the point-to-point link on a one-to-one basis. ,And,
After converting the ATM cells received from the transit router network via the ATM logical connection on the ATM link into a packet, the ATM header of the packet is converted into a point-to-point link header, and one pair of the ATM logical connection is provided. 1. In a packet transfer method provided with an ATM conversion node for transferring to a point-to-point link corresponding to No. 1, the ATM conversion node reads a destination of an IP packet received from the point-to-point link, and Means for resolving the ATM address of an egress ATM conversion node that is an egress from the ATM network; and setting up a logical connection that bypasses the transit router network to the ATM conversion node using the resolved ATM address. The packet using the egress A
Means for reading the destination of the IP packet received from the logical connection bypassing the relay router network, and a point-to-point corresponding to the destination. A packet transfer method comprising: a means for selecting a point link; and a means for transmitting the IP packet to the point-to-point link with a point-to-point link header corresponding to the destination. 2. The packet transfer method according to claim 1, wherein the point-to-point link includes a logical point-to-point link realized by a logical channel. 3. The packet transfer system according to claim 1, wherein the inbound ATM conversion node, which is an entrance to an ATM network that receives a packet from a point-to-point link in the address resolution means, receives the packet from the ATM network. An address resolution request packet describing the destination IP address of the received packet is sent to the relay router network in order to resolve the ATM address of the egress ATM conversion node exiting from the relay router network, and the relay router network has the destination IP address. When the destination of the packet is a point-to-point link accommodated by another ATM conversion node,
Enter the ATM address of the other ATM conversion node into the entrance AT
A packet transfer method for notifying an M conversion node. 4. The packet transfer method according to claim 3, wherein the relay router network determines whether the egress ATM conversion node has a function of setting a logical connection that bypasses the relay router network. As
A packet transfer method comprising means for holding a table of ATM conversion nodes having a function of setting a logical connection that bypasses the relay router network. 5. The packet transfer method according to claim 3, wherein the relay router network determines whether the egress ATM conversion node has a function of setting a logical connection that bypasses the relay router network. A logic for transmitting a hello message to the conversion node, and when receiving the hello message, the ATM conversion node returns a hello message corresponding to the hello message in response to the hello message, and bypasses the relay router network. A packet transfer method for notifying that it has a connection setting function. 6. The packet transfer method according to claim 3, wherein said ATM conversion node determines whether said transit router network has a function of performing address resolution processing. A packet transfer method comprising means for holding a table of relay routers having functions. 7. The packet transfer method according to claim 3, wherein the ATM conversion node sends a hello message to the relay router to determine whether the relay router network has a function of performing an address resolution process. Transmitting the relay router, upon receiving the hello message, returning a hello message corresponding to the hello message to the hello message to notify that the relay router has a function of performing the address resolution processing. Characteristic packet transfer method. 8. The packet transfer method according to claim 3, wherein the relay router network is configured to determine, at the time of the address resolution, a destination I of a packet to be received by the egress ATM conversion node from a logical connection that bypasses the relay router network.
Means for notifying the egress ATM conversion node of the P address, the egress ATM conversion node obtains a point-to-point link corresponding to the notified destination IP address, and obtains the destination IP address and the destination IP address. Characterized in that it has means for retaining a correspondence relationship with the point-to-point link corresponding to the address and information necessary for adding the point-to-point link header corresponding to the destination IP address. method. 9. The packet transfer method according to claim 8, wherein the relay router network sets a destination IP address of a packet to be received by the egress ATM conversion node from a logical connection bypassing the relay router network. A
When notifying the TM conversion node, an identifier capable of uniquely identifying the ATM logical connection used when the relay router network transfers the packet of the destination IP address line to the egress ATM conversion node on the egress ATM conversion node side. At the same time, the relay router network notifies the egress ATM conversion node, and the egress ATM conversion node determines the ATM logical connection from the received destination IP address and the identifier of the notified ATM logical connection. A point-to-point link corresponding to the packet transfer method. 10. The packet transfer method according to claim 9, wherein an identifier for uniquely identifying a logical connection accommodated in said ATM conversion node is previously negotiated between said ATM conversion node and said relay router network. Characteristic packet transfer method. 11. The packet transfer method according to claim 8, wherein the relay router network determines a destination IP address of a packet to be received by the egress ATM conversion node from a logical connection bypassing the relay router network. ATM used when transferring the notification packet when notifying the ATM conversion node and transferring the packet of the destination IP address line from the relay router network to the egress ATM conversion node
A logical connection is sent to the egress ATM conversion node, and the egress ATM conversion node obtains a point-to-point link corresponding to the ATM logical connection one-to-one from the ATM logical connection that has received the notification packet. A packet transfer method for generating a correspondence between an IP address and a point-to-point link. 12. The packet transfer method according to claim 1 or 2, wherein the address resolving means, when the other ATM conversion node notifies the relay router network of an ATM address, points to the relay router. A packet transfer method for notifying using an ATM logical connection corresponding to a two-point link. 13. An ATM cell having one or a plurality of point-to-point links and one or a plurality of ATM links, and adding an ATM header to a packet received from the point-to-point link. The ATM router converts the data and transfers it to the relay router network in the ATM network by using a predetermined ATM logical connection on the ATM link corresponding to the point-to-point link on a one-to-one basis. After converting the ATM cell received through the ATM logical connection into a packet, the ATM header of the packet is deleted, and the ATM
In a packet transfer system including an ATM conversion node for transferring a logical connection to a point-to-point link corresponding to one-to-one, the ATM conversion node reads a destination of an IP packet received from the point-to-point link, Means for resolving the ATM address of an egress ATM translation node which exits from the ATM network in accordance with the destination, and setting up a logical connection to bypass the transit router network using the resolved ATM address up to the ATM translation node. , Using the logical connection to route the packet to the egress A
Means for transmitting to the TM conversion node, the egress ATM conversion node reads the destination of the IP packet received from the logical connection bypassing the transit router network, and a point-to-point link corresponding to the destination. A packet transfer method, comprising: means for selecting; and means for adding the point-to-point link to the point-to-point link with a header for the point-to-point link corresponding to the destination and transmitting the IP packet. 14. The packet transfer system according to claim 13, wherein said point-to-point link includes a logical point-to-point link realized by a logical channel. 15. The packet transfer system according to claim 13, wherein the ingress ATM conversion node, which is an entrance to an ATM network that receives a packet from a point-to-point link in the address resolution means, receives the packet from the ATM network. An address resolution request packet describing the destination IP address of the received packet is sent to the relay router network in order to resolve the ATM address of the egress ATM conversion node exiting from the relay router network, and the relay router network has the destination IP address. When the packet transfer destination is a point-to-point link accommodated by another ATM conversion node, the ATM address of the other ATM conversion node with a shortcut delivery function is notified to the entrance ATM conversion node. Transfer method. 16. A packet transfer method according to claim 15, wherein said relay router network determines whether said egress ATM conversion node has a function of setting a logical connection that bypasses said relay router network. And a means for holding a table of ATM conversion nodes having a function of setting a logical connection that bypasses the relay router network. 17. The packet transfer method according to claim 15, wherein the relay router network determines whether the egress ATM conversion node has a function of setting a logical connection that bypasses the relay router network. ATM
The ATM conversion node transmits a hello message to the conversion node, and when the hello message is received, the ATM conversion node returns a hello message in response to the hello message, and has a logical connection setting function of bypassing the relay router network. A packet transfer method for notifying the user of the fact. 18. The packet transfer system according to claim 15, wherein said ATM conversion node determines whether said transit router network has a function of performing address resolution processing. A packet transfer method comprising means for holding a table of relay routers having functions. 19. The packet transfer method according to claim 15, wherein the ATM conversion node sends a hello message to the relay router to determine whether the relay router network has a function of performing address resolution processing. Send,
When the relay router receives the hello message,
A packet transfer method, wherein a hello message is returned to the hello message to notify that the hello message has a function of performing the address resolution processing. 20. The packet transfer method according to claim 15, wherein the relay router network is configured to set a destination IP address of a packet to be received by the egress ATM conversion node from a logical connection that bypasses the relay router network during the address resolution. Means for notifying the egress ATM conversion node of an address and point-to-point link header information to be added to the packet to be received,
The M conversion node, in accordance with the contents of the notification, associates the destination IP address with the point-to-point link corresponding to the destination IP address and the point-to-point link header information corresponding to the destination IP address. A packet transfer system having means for holding.