JPH08340355A - Connection method between communication networks - Google Patents

Abstract

(57) [Summary] [Purpose] To connect networks without assigning logical networks to communication networks. In the inter-communication network connection method for connecting the routers connected to each LAN via the frame relay network 1, when the router 10 receives data to be relayed via the frame relay, the transmitting side router 10 Is
The LAN side address of the relay destination router 20 is used to specify the relay destination router 20, and the packet format data is transmitted to the frame relay network using the frame relay logical channel corresponding to the LAN side address. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a frame relay network to connect TCP between communication networks forming a LAN.
The present invention relates to a connection method between communication networks for connecting at a network layer such as / IP (Transmission Control Protocol / Internet Protocol) method.

[0002]

2. Description of the Related Art Conventionally, in this type of connection method between communication networks, a frame relay network, which is a wide area communication network, is logically treated as one network by using a connection device such as a router connected to a LAN. , LAN connection was made at the network level. In this LAN-to-LAN connection method, when the router receives data from the LAN-side terminal device to which the router is connected, the router searches for the network number of the relay destination router address corresponding to the transmission destination address,
Further, the network number of the retrieved relay destination router address is compared with the network number of the address (representing the logical channel) set in the frame relay interface. When these network numbers match, the router relays the data to the frame relay.

[0003]

However, in the above connection method, when the logical channels are connected in a tree form, each logical channel of the frame relay needs to be treated as a logically separate network. There is a problem that the network design work for assigning the network number and the design work for the router are complicated.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a connection method between communication networks which can connect the networks without assigning a logical network to the communication network.

[0005]

In order to achieve the above object, according to the present invention, a connecting device such as a router connected to each communication network consisting of a LAN is connected to a logical channel of a communication network consisting of a frame relay network. In the inter-communication network connection method of connecting via the router, the router on the transmission side uses the network-side address of the router of the relay destination to identify the relay partner, and also establishes the logical channel corresponding to the network-side address. A method for connecting between communication networks for providing the data to the frame relay network using the communication method is provided.

According to a second aspect of the present invention, the connection device comprises a network side address of a transmission destination and a network side address of a relay destination router corresponding to the address.
Table, a network side address of the router, and the logical channel corresponding to the address, and when data is received from the LAN side, the relay destination is changed from the first table. The network side address of the router is searched, and the logical channel corresponding to the searched network side address is searched from the second table.

In the third aspect, each of the routers exchanges address information by using the network side address when the network is added or changed.

[0008]

When the data to be relayed to the frame relay interface of the router is received, the router to be relayed is determined using the network (LAN) side address of the router connected through the frame relay logical channel. Then, the packet format data is transmitted.

In the communication network connecting method of the present invention, the router has a network side address of a relay destination router corresponding to a transmission destination network side address and a logical channel corresponding to the router network side address. It has two tables consisting of, and transmits data without requiring logical network allocation on the frame relay.

In the inter-communication network connection method of the third aspect, the LAN side address of the connected router is exchanged and learned, and the learned LAN side address of the partner router is used for data communication.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for connecting communication networks according to the present invention will be described with reference to the drawings of FIGS. FIG.
FIG. 1 is a block diagram showing a schematic configuration of a data communication system using a method for connecting communication networks according to the present invention. In the figure, in this embodiment, a plurality of connection devices (hereinafter, referred to as “routers”) 1 having a router function are provided via a frame relay (hereinafter, referred to as “FR”) network 1.
0, 20, 30, 40 are connected.

The LAN 1 is constructed from a router 10, a terminal device (not shown), and a transmission line 11 to which the router 10 and the terminal device are connected. LAN2 is router 20
And a terminal device (not shown) and a transmission line 21 to which the router 20 and the terminal device are connected. LAN3
Is a router 30, a terminal device (not shown), and a router 30.
And a transmission line 31 to which the terminal device is connected. The LAN 4 is constructed from a router 40, a terminal device (not shown), and a transmission line 41 to which the router 40 and the terminal device are connected.

Each router 10, 20, 30, 40 has a routing table for route control and an ARP (address resolution protocol) table for FR control. Since both tables held by each router are almost the same, both tables of the router 10 will be described here.

In the routing table, as shown in Table 1, a destination address indicating information on the network side address of the transmission destination and a relay destination router address indicating the network side address of the relay destination router corresponding to this destination address. And are remembered. In the configuration of this address information, the upper three numbers are assigned corresponding to each network, and the fourth lowest number is assigned corresponding to each router or terminal device in the network. . In this address information, the address information when the lowest digit is "0" represents the entire network.

[0015]

[Table 1]

In the routing table of the router 20, the destination address "192.52.130.0" indicating the network address of the LAN 2 and the relay destination router address "192.52. LAN1 instead of 130.1 "
Destination address indicating the network side address of "19
2.52.128.0 "and the corresponding router 10
The relay destination router address “192.52.128.1”, which indicates the network side address, is stored. Similarly, in the routing table of the router 30, L
Destination address “192.52.131.0” indicating the network side address of AN3 and relay destination router address “19” indicating the network side address of the router 30.
Router instead of 2.52.131.1 "
In the routing table of the destination address “192.52.13.
2.0 "and the relay destination router address" 192.52.132.1 "indicating the network side address of the router 40
Instead of the destination address "192.52.12"
8.0 "and the corresponding relay destination router address" 1 "
92.52.18.1 ”is stored.

Further, in the ARP table, as shown in Table 2, a hardware address (DLCI (Data Link Connection Identifier)) indicating the information of the logical channel of the FR network 1 and this DLCI IP address indicating the network side address of the corresponding relay destination router (LAN interface address (LI
FA)) is stored.

[0018]

[Table 2]

In the ARP table of the router 20,
Instead of the hardware address of the logical channel “16” and the IP address “192.52.130.1” of the router 20, the logical channel “15” and the IP address “192.52” of the router 10 corresponding to this logical channel “15”. .128.
1 ”is stored. Similarly, the router 30 A
In the RP table, the hardware address of the logical channel “17” and the IP address of the router 30 “192.5
AR of router 40 instead of 2.131.1 "
In the P table, the hardware address of the logical channel "18" and the IP address of the router 40 "192.5"
Logical channel "15" instead of 2.132.1 "
And the IP address “19” of the router 10 corresponding to this
2.52.128.1 "is stored.

In addition to the data communication between LANs via the FR network, for example, the same LAN is used for data communication.
Data communication may be performed between the terminal devices existing in the inside. Further, there are cases where a plurality of networks are connected to the same LAN via a router and data communication is performed between these networks. In these cases, each router 10,
20, 30, 40, the destination terminal device is the LAN side, FR
It is also possible to hold an interface table for judging whether each side is located.

Table 3 shows the interface table.
As shown in FIG. 5, an interface indicating that the connected network is either the LAN side or the frame relay side and the network address corresponding to the interface are stored.

[0022]

[Table 3] Further, in this embodiment, in the interface tables of the routers 20, 30, 40, the network address “192.52.128.0” of LAN 1 is stored instead of the network address of the own device.

In addition to the above, a subnet mask indicating which part of the LIFA represents a network and a broadcast address necessary for sending a control packet are set in each router 10, 20, 30, 40. .
Each router 10, 20, 30, 40 has the same LA as its own device.
When the packet for LAN transmission in FIG. 2 is received from the terminal device in N, a broadcast packet for relay as shown in FIG. 3 is created based on the addresses in the routing table and the ARP table, and the frame relay is performed. Send to network 1.

The packet for transmission shown in FIG. 2 has an Ethernet header indicating the physical protocol to be used and an IP
-It is composed of a header and data to be transmitted to the destination terminal device. The Ethernet header has information on the Ethernet hardware address (dst) of the router on the LAN side and information on the Ethernet hardware address (src) of the source terminal device. Also, I
The P-header has the information of the network side address (dst) of the destination terminal device and the information of the network side address (src) of the terminal device of the same source as the Ethernet header.

The relay packet shown in FIG. 3 is composed of an FR header, an IP header, and data to be transmitted to the destination terminal device. The FR header has a logical channel representing a logical channel and a control protocol. The IP header and data are the same as the IP header and data of the packet for transmission.

Here, for example, a case where data is transmitted from the terminal device of LAN1 to the terminal device of LAN2 will be described. The router 10 receives a packet for transmission from the terminal device of LAN1. In this case, the dst of the Ethernet header of the transmission packet is the Ethernet hardware address of the router 1 of LAN 1 (that is,
Network side address "192.52.12.8.1"
The Ethernet 1 hardware address of the router 1) and src are the Ethernet hardware address of the terminal device of the transmission source of the LAN 1. Further, dst of the IP / header is the network side address “192.52.130.
5 ", and src includes information on the network side address of the source terminal device of the same LAN 1 as the Ethernet header. Dst of the FR header is LA
The N2 router 2 consists of logical channel information "16".

Upon receiving the packet for transmission, the router 10 receives dst "192.52.13" of the IP header.
Search the routing table based on 0.5 ",
Destination address "19" that has the same address as this dst
The relay destination router address “192.52.130.1” corresponding to 2.52.130.0 ”is acquired.
The router 10 uses the relay destination router address “192.5
The ARP table is searched by using 2.130.1 "as the LIFA, and the logical channel" 16 "of the corresponding DLCI is acquired.

Next, the router 10 creates an FR header with the acquired logical channel "16" as dst and adds a relay packet in which the FR header is added to the head of the IP header as the FR packet. Send to network 1. Therefore, in this embodiment, since the interface address on the LAN side is transmitted and received to perform packet communication, data communication can be performed without being aware of the FR interface address, and a network number is assigned to each logical channel. Network design work and router design work become easy.

When the router 10 also holds the interface table shown in Table 3, the router 10
When the relay destination router address “192.52.130.1” is acquired from the routing table, the interface table is searched and the same network address “192.52.13” as the relay destination router address is acquired.
It is confirmed that the interface having 0.0 ”is the FR interface. Then, the router 10 sets the relay destination router address“ 192.52.130.1 ”.
As a LIFA, the ARP table is searched to obtain the logical channel “16” of the corresponding DLCI.

Even in this case, since the data is transmitted to the FR network using the logical channel corresponding to the interface address on the LAN side, it is possible to connect the LANs without assigning a logical network to the FR network. Further, the router according to the present invention exchanges network address information when a new LAN is added or a LAN network address is changed.

FIG. 4 is a block diagram showing a schematic configuration of a data communication system when a router is added to a new logical channel. In the figure, LAN 5 is a router 50
And a terminal device (not shown) and a transmission line 51 to which the router 50 and the terminal device are connected. In the router 50, DLCI is “19” and LIFA is “19”.
It is set to 2.52.133.1 ".

When the router 50 is connected to the FR network 1,
Information on network side addresses is exchanged with each router 10, 20, 30, 40. As a typical example, information exchange with the router 10 will be described. First, new router 5
When 0 is added and the line of the logical channel “19” becomes active, each router 10, 20, 30,
40 is notified that the "19" line has been activated.

Next, the router 50 creates an ARP packet and sends the ARP packet to the FR network 1 to make a request for routing information exchange. In addition, AR
The P packet is configured as shown in FIG. 5, and the router 50 has the DLCI information “19” of its own device in the address area and the router address information “192.52” of its own device in the ARP packet area. .133.1 "is set and transmitted.

The router 10 FRs the ARP packet.
When received via the network 1, the router addresses of the router 50 in the address area and the ARP packet area are learned, and as shown in Table 4, the logical channel “19” is set in the DLCI of the ARP table and the logical channel “19” is set. "192.52.133.1" corresponding to is added to LIFA.

[0035]

[Table 4]

Then, the router 10 stores the information "15" of the DLCI of the own device in the address area and the information "192.5" of the router address of the own device in the ARP packet area.
2.12.1 "is set to create an ARP packet,
The ARP packet is transmitted to the FR network 1 to make a response. As a result, the router 50 can also create the ARP table.

Next, the router 50 creates a broadcast packet and exchanges routing information.
Here, the router 50 sets the logical channel of the FR header of the packet to “15”, and the ds of the IP head.
t to “192.52.128.1” and src to “19
2.52.133.1 ", and the information of the destination address" 192.52.133.0 "and the number of routers for relaying is entered as IP data to create a broadcast packet, and FR The packet is transmitted to the router 10 via the network 1.

When the router 10 receives the above-mentioned broadcast packet via the FR network 1, the router 10 receives the s packet of the IP head.
Based on the information of the rc and IP data, as shown in Table 5, “192.52.133.0” is set as the destination address of the routing table, and the src “192.52.133” corresponding to the destination address is set. .1 ”to the relay router address.

[0039]

[Table 5] In addition, when the router 50 holds the interface table, as shown in Table 6, based on the information of the src of the IP head and the data of the IP, “19
It is also possible to add 2.52.133.0 "to the network address on the FR side of the interface table.

[0040]

[Table 6]

Next, the router 10 creates a broadcast packet based on the routing information of its own device and transmits the packet to the router 50. As a result, the router 50 can also create the routing table and the interface table. Further, the router 50 can exchange routing information with the other routers 20, 30, 40 in the same manner.

FIG. 6 is a block diagram showing a schematic configuration of a data communication system when a new network is connected to another network via a router. In this case, the routing information can be exchanged between the router 40 and the router 10 by a broadcast packet. Therefore, as shown in Table 7, the router 10 stores the destination address “192.52.133.0” in the routing table and the relay destination router address “19” corresponding to the destination address based on the routing information of the packet.
2.52.132.1 "can be added.

[0043]

[Table 7] Therefore, in the embodiment shown in FIGS. 4 and 6, the routing information can be exchanged using the network side address without allocating a logical network to the FR network.

[0044]

As described above, according to the present invention, in the inter-communication network connection method for connecting the connection device connected to each communication network through a logical channel of the communication network, the connection on the transmission side is performed. The device uses the network address of the connection device of the relay destination to identify the relay partner, and transmits the data to the communication network using the logical channel corresponding to the network address. You can connect networks without assigning logical networks to the networks.

According to a second aspect of the present invention, the connection device has a first table including a network side address of a transmission destination and a network side address of a connection destination device of a relay destination corresponding to the address, and a network side of the connection device. It has a second table consisting of an address and the logical channel corresponding to the address, and when data is received from the communication network side, the network side address of the connection device of the relay destination is received from the first table. Since the search and the logical channel corresponding to the searched network side address are searched from the second table and the data is transmitted, the network level setting in the communication network can be made unnecessary.

In the third aspect, since each connection device exchanges the address information by using the network side address for the addition or change of the network, without assigning a logical network to the communication network, It is possible to exchange routing information.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a data communication system using an inter-communication network connection method according to the present invention.

FIG. 2 is a configuration diagram showing a configuration of a packet for LAN transmission.

FIG. 3 is a configuration diagram showing a configuration of a packet for relay.

FIG. 4 is a block diagram showing a schematic configuration of a data communication system in which a router is added to a new logical channel.

FIG. 5 is a configuration diagram showing a schematic configuration of an ARP packet.

FIG. 6 is a block diagram showing a schematic configuration of a data communication system when a new network is connected to another network via a router.

[Explanation of symbols]

 1 Frame relay (FR) network 10, 20, 30, 40, 50 Router 11, 21, 31, 41, 51 Transmission line LAN1 to LAN5 Local area network

Claims (4)

[Claims] 1. A connection method between communication networks for connecting a connection device connected to each communication network via a logical channel of the communication network, wherein the connection device on the transmission side is a network of the connection device of a relay destination. A method for connecting between communication networks, characterized in that a relay partner is specified using a side address, and the data is transmitted to the communication network using the logical channel corresponding to the network side address. 2. The connection device, a first table including a network side address of a transmission destination and a network side address of a connection destination connection device corresponding to the address, a network side address of the connection device, A second table consisting of the logical channel corresponding to the address, and when receiving data from the communication network side, retrieves the network side address of the connection device of the relay destination from the first table, The communication network connecting method according to claim 1, wherein a logical channel corresponding to the searched network side address is searched from the second table. 3. The inter-communication network connection method according to claim 1, wherein each of the connection devices exchanges address information by using a network-side address when a network is added or changed. . 4. The method according to claim 1, wherein the communication network is a local area network, and the communication network is a frame relay network.