JPS63196132A - Routing system - Google Patents

Abstract

PURPOSE:To execute routing without requiring a length corresponding to the relation between a terminal equipment and a node by using a multiple address received by all nodes so as to transfer to all nodes and allowing the received node to judge whether or not a destination address is checked and transferred. CONSTITUTION:Nodes 2-5 consist respectively of a part A applying transmission/reception of each local area network side and a part B applying transmission/reception of a trunk network side. The part A checks a destination terminal address of a packet on a local area network, and judges the necessity of the transfer only when a table (a) is not described to give the packet to the part B. The part B adds a trunk network header using a destination node address as a multiple address to a packet given from the part A and sends the result to the trunk network. The part B looks into the destination node address of the packet sent through the trunk network and receives the data only when it is its own address or a multiple address.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a routing system within a backbone network when terminals on a plurality of local area networks communicate via one backbone network.

(Prior Art) In a packet communication system in which multiple local area networks of the same type connecting multiple terminals are connected to multiple nodes of a single backbone network with broadcasting characteristics, communication between the terminals is usually as follows. It will be held in Each terminal transmits an information frame with the destination terminal's address and its own terminal's address, regardless of whether the other terminal is connected to the other's local area network. If the destination terminal is directly connected to the same local area network as the sending terminal, the destination terminal receives the information frame directly by looking at its destination address. On the other hand, the node looks at the destination address of the information frame, and if the destination terminal is directly connected to the local area network it accommodates, it will not receive it; A backbone network that receives the information frame when connected to the network, looks up the table to find out which node the destination terminal is accommodated in, and sets the address of the node as the destination address and the address of the own node as the source address. The inner header is added to the front of the received information frame and transmitted onto the backbone network. A node receives an information frame flowing on the backbone network only when the destination address is its own node address, removes the header within the backbone network, and then transmits it to the local area network accommodated in the node.

(Problems to be Solved by the Invention) According to the above method, each terminal operates as if it were a fellow terminal connected to one local area network, regardless of which local area network the other terminal is connected to. Communication is possible.However, each node must maintain a correspondence table between the addresses of all terminals and the nodes that accommodate them.This address correspondence table needs to be dynamically changed according to changes in the system configuration, etc. Therefore, the processing load for updating is heavy.Furthermore, the processing load for searching the address correspondence table and converting addresses for each packet to be transferred is also heavy.

(Means for Solving the Problems) In the present invention, instead of specifying a specific node and forwarding, the forwarding node side forwards the data to all nodes using a broadcast address that all nodes receive. , the receiving node looks at the destination terminal address and decides whether to forward it or not, thereby eliminating the need for a correspondence table between terminals and nodes at the source node, and eliminating the need for address conversion processing. It is a method.

(Example) Next, embodiments of the present invention will be described using the drawings.

FIG. 1 is a diagram showing an example of the configuration of a system for explaining the present invention in detail. In the figure, 1 is the backbone network,
2 to 5 are nodes of the backbone network, 6 to 9 are local area networks accommodated, and 10 to 17 are terminals accommodated in the local area networks.

Each of the nodes 2 to 5 is composed of a part A that performs transmission and reception on the local area network side and a part B that performs transmission and reception on the backbone network side. A maintains a table (referred to as Table A) of the addresses of terminals that are known to be connected to the local area network to which it is connected, and B maintains a table of addresses of terminals that are known to be connected to the local area network to which it is connected. It maintains a table (called a representation) of the addresses of terminals that are known not to be connected to the local area network.

A looks at the destination terminal address of the packet on the local area network, determines that forwarding is necessary only when it is not listed in Table a, and passes the packet to B. B adds a backbone network header with the destination node address as a broadcast address to the packet passed from A, and transmits the packet onto the backbone network. This is illustrated in Figure 2. Figure 2(a) is a diagram showing the format of a packet on the local area network, Figure 2<b) is a diagram showing the format of a packet on the backbone network, and Figure 2(c) is a diagram showing the format of a packet on the backbone network. FIG. 3 is a diagram showing the format of a packet when transferring.

B looks at the destination node address part of the packet flowing on the backbone network, and receives the packet only if it is its own node address or a broadcast address. Since the destination node address of the transfer packet is a broadcast address, all nodes B receive it. Once received, B represents the destination terminal address written inside the backbone network header, and only if the destination terminal address is not written in the backbone network header part of the received packet is removed. Give it to A. A sends the packet passed from B as is to the local area network to which it is connected.

In the method explained above, table a is, for example, A of each node.
This can be obtained by recording the source terminal address of all packets flowing on the local area network to which it is connected.

The representation can be obtained, for example, by recording the source terminal addresses of all transfer packets flowing on the backbone network at B.

(Effects of the Invention) According to the present invention, each node does not need a correspondence table between terminals and the nodes that accommodate them, but simply information on whether or not the terminal is accommodated in the local area network to which it is connected. Routing can be done using only

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the configuration of a system implementing the method of the present invention, and FIG. 2 is a packet format diagram for explaining the present invention. In Figure 1, 1 is the backbone network, 2
~5 is a node, 6~9 is a local area network,
10 to 17 are terminals. Figure 2 (a) is the packet format within the local area network, (b) is the packet format within the backbone network, and <c) is the forwarding packet. Figure 1 Figure 2 (a)

Claims (1)

[Claims] In a packet communication system in which multiple local area networks that connect multiple terminals are connected to multiple nodes of a backbone network that has broadcasting properties, the nodes of the backbone network transmit data on the local area network connected to themselves. If a packet that should be forwarded to another node is forwarded to all nodes in the above communication system, and all other nodes that receive the forwarded packet need to check the destination terminal address and forward it. A routing method characterized in that only the received packet is transferred to a local area network to which it is connected.