JPH02214349A - Scma/cd bus bridge - Google Patents

Abstract

PURPOSE:To eliminate the need for the deletion of a table with time management of other node terminal equipment by revising other node terminal equipment table and own node terminal equipment table automatically so as to retrieve and register the address of a transmission terminal equipment from the CSMA/CD bus frame. CONSTITUTION:When additional registration and deletion is applied, a table management means 19 uses a communication means 8 for table revision content to add an MAC header including a simultaneous destination node address, a sender address SNA of a node 9 and node control(NC) representing the table revision content and sends the result to a back bone network. Nodes 10, 11 receive a frame and recognize the content of table revision, then the communication means 8 for table revision content in each node gives the content of table revision to the table management means 19. The table management means 19 revises other node terminal equipment table and revises it relating to the node 9 of the sender address according to the content of table revision.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a local area network, and in particular to a CSMA/CD (Carrier Network) having an absolute address system.
5ense Multi Access / Co11
This invention relates to a CSMA/CD bus bridge consisting of a backbone network and nodes that connect a bus to a high-speed backbone network.

[Prior art] Conventionally, this type of CSMA/CD bus bridge
If there are two nodes with A/CD buses, each node has a boat with a CSMA/CD bus interface that connects terminals to the node, and each boat has the address of the terminal connected to that boat. It has a table for registration, searches that table for the destination address (hereinafter referred to as DA) of the frame received by each boat, and if it does not exist, sends the frame to the backbone network, and if it exists in its own table has an address filtering function that prevents transmission, and each boat's table is searched for the source address (hereinafter referred to as SA) of the frame received by each boat, and if it does not exist, it is added and registered. Or, by deleting the terminal address that is not searched again even after a certain period of time has passed since the search, the terminal address of the terminal connected to each boat side is automatically updated.
It also has a function to automatically change the table for terminals added to the SMA/CD bus and terminals disconnected from the C8MΔ/CD bus. Additionally, if three or more nodes accommodating terminals are connected to the backbone network using the CSMA/CD bus, each node accommodating the terminals must be It has a table consisting only of the terminal addresses accommodated in the node, and searches the table for the DA of the frame received from the CSMA/CD bus, and if it exists, it will not send it, and if it does not exist, it will not send it on the backbone network. When the frame is broadcast and received, another node searches its own table regarding the DA and if it exists, the C
There is a method of transmitting the frame to the SMA/CD bus, and if there is no frame, it is not transmitted. Each node has a table of terminals accommodated by itself and a table of terminals accommodated by other nodes, and the frame is transmitted from the CSMA/CD bus. CSMA/CD
Each table is searched for bus frame OA, and if it exists in the table of the terminal accommodated by the own node, this frame is not transmitted, and if it exists in the table of the terminal accommodated by another node, the corresponding node It obtains the node address of , and sends this frame only to that node, and if it does not exist in both tables, sends it to the backbone network with a broadcast destination attached, and receives this frame from the backbone network side. There is a method in which a node searches a table of terminals that it accommodates regarding DA and, if it exists, transmits this frame to the CSMA/CD bus.

[Problem to be solved by the invention]

In the conventional CSMA/CD bus bridge described above, when three or more nodes are accommodated in a backbone network, each node has a table consisting only of terminal addresses accommodated in its own node. This has the disadvantage that all transmissions are broadcast transmissions, and the throughput on the network cannot be increased by exchanging frames.In addition, conventionally each node has a table of terminals accommodated by itself and a table of terminals accommodated by other nodes. In the method with a table, the throughput can be increased compared to the previous method by exchanging frames on the backbone network, but if you apply the traditional bridge learning method as a method to obtain a dynamic table, the backbone network side Regarding the boat table, it is necessary to have a means to search and register the source node address and the SA of the transmitting terminal from the frame received from the backbone network side, and a means to delete the addresses of other node terminals by timer management. It has the disadvantage of becoming

[Means to solve the problem]

When the CSMA/CD bus bridge of the present invention newly registers the address of a terminal that has started packet transmission in its own node terminal table, or deletes the address of a terminal that has completed packet transmission, a means for transmitting the changes to other nodes;
Each node has means for, upon receiving changes to its own node terminal table from another node, updating the contents of the corresponding node in the other node terminal table with the received changes.

[Effect]

At each node on the same backbone network,
By automatically updating the own node terminal table and other node terminal table, the source node address of the frame received from the backbone network side and the address of the transmitting terminal can be searched from the C8M△/CD bus frame of that node. There is no need to register and delete terminals of these loose nodes through time management.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the CSMA/CD bus bridge of the present invention.

This CSMA/CD bus bridge is node 9°10.1
1 and a backbone network that connects them. Node 9 has CSMA/CD bus interface 1, backbone network interface 2, own node terminal table 3, other node terminal table 4 consisting of own node terminal tables of all other nodes, and media access III 111. unit (hereinafter referred to as MAC conversion unit) 5, searches the own node terminal table 3 regarding the SA of the frame received from the CSMA/CD bus, and if there is no SA, additionally registers SA search and addition registration means 6, SA search and addition terminal address deletion means 7 for deleting a terminal address in the own node terminal table 3 for which the next SA is not searched by the search additional registration means 6 even after a certain period of time has elapsed after the registration and search by the registration means 6; When the own node terminal table 3 is changed by the SA search addition registration means 6 or the terminal address deletion means 7, the changed contents are sent to other nodes 10.11, and the contents of the other nodes 10.11 are changed. It consists of a table change content communication means 8 for receiving the change contents of the own node terminal table 3, and a table management means 19. Nodes 9.10.11 and 12.13.14.1 are backbone network nodes each having a CSMA/CD bus bridge function.
5.16゜17.18 are terminal addresses A, B, respectively.
C.

It is a CSMA/CD bus terminal with D, E, F, and G. The table management means 19 includes the SA search additional registration means 6;
When the own node terminal table 3 is changed by the terminal address deletion means 7, the transmission of the table change contents to the communication means 8 is started, and the communication means 8 of the table change contents is changed from the node 10 or 11. When the content is received, the table corresponding to the node 10 or 11 in the other node terminal table 4 in the node 9 is changed. In the CSMA/CD bus frame 20, node 9 is terminal 1
Frame 21, which is a frame received from node 2 or 13, is a frame that node 9 transmits to node 10 or 11 via the backbone network. The address filtering function of node 9 uses the received CSMA/CD
Regarding DA of the bus frame 20, the M to C converter 5 searches the own node terminal table 3 and the other node terminal table 4, and if it exists in the own node terminal table 3, discards the frame and 4, get the corresponding node address and use this as the destination node address DNA (destinationNode A
In addition to this, the source node address 5NA (Source ddress) indicating the node address of node 9 is
Mode Address) and this frame is CS
A MAC header consisting of a node control @NC (Mode Control) indicating that communication is between terminals on the MA/CD bus is added to the CSMA/CD bus frame 20, and the frame 21 is transmitted to the backbone network. node 10 or node 11 for frame 21 with this destination node address DNA.
checks the node control NO, and this is the CSMA/
When it recognizes that the communication is to a CD bus terminal, it removes the MAC header of the backbone network and transmits it to the CSMA/CD bus connected to its own node. Further, if the SA of the CSMA/CD bus frame 20 received by the node 9 does not exist in both the own node terminal table 3 and the other node terminal table 4, the node 9 uses the destination node address DNA as the broadcast node address. , C
The SMA/CD bus frame 20 is transmitted as a frame 21 to the nodes 10 and 11.

Next, a learning method for the terminal table of node 9 will be explained. Terminal 12 or 13 sends a CSMA/CD bus frame 20 and CSMA/CD bus interface 1
When the node 9 receives the SA through the CSMA/CD bus frame 20, the SA search/add means 6 searches its own node terminal table 3 regarding the SA of this CSMA/CD bus frame 20. Own node terminal table 3
If the terminal address exists, the timer for that terminal address is reset. If the SA is not in the self-node terminal table 3, the SA is additionally registered as a terminal address, and a timer related to the terminal address is set.

The terminal address deletion means 7 updates the timer related to the terminal address in the own node terminal table 3, and deletes from the own node terminal table 3 the terminal address related to the timer for which a certain period of time or more has elapsed. When the above-mentioned additional registration and deletion are performed, the table management means 19 transmits the changed contents through the table changed contents communication means 8, the simultaneous destination node address, the source address SNA of the node 9, and the node control indicating the table changed contents] ( A MAC header containing NC) is added and transmitted to the backbone network.

When the nodes 10 and 11 receive this frame and recognize the table change contents, the table change contents communication means 8 in each node passes the table change contents to the table management means 19, and the table management means 19 recognizes the table change contents. The other node terminal table regarding node 9 having the source address is changed and updated according to the contents.

〔Effect of the invention〕

As explained above, the present invention automatically updates the own node terminal table and the other node terminal table in each node on the same backbone network, so that the source node address can be determined from the frame received from the backbone network side. The registration of a terminal that uses a lot of communication in both terminal tables is maintained and the terminal can be accommodated without having to search for and register the SA of the sending terminal and delete the terminals of other nodes by time management. Direct transmission to nodes is possible, which has the effect of increasing the throughput of the backbone network.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the CSMA/CD bus bridge of the present invention. 1... CSMA/CD bus interface, 2...
- Backbone network interface, 3... Own node terminal table, 4... Other node terminal table, 5... MAC converter, 6... SA search and additional registration means, 7... Terminal address Deletion means, 8... Communication means of table change contents, 9.10.11
...Node, 12-18...Terminal, 19...Table management means, 20...CSMA/CD bus frame,...Frame.

Claims (1)

[Claims] 1. CSMA/C that connects multiple terminals belonging to the same LAN and having absolute addresses to a backbone network
D bus interface, a self-node terminal table in which addresses of terminals accommodated in the CSMA/CD bus are registered, and terminals accommodated in other nodes connected to the backbone network via the CSMA/CD bus. Search the own node terminal table and other node terminal table for the destination address of the frame received from the CSMA/CD bus side, and search the other node terminal table in which the address of the terminal that is present is registered for each node. If the frame is in the other node terminal table, it is sent to the backbone network with a media access control header that uses the node address of the node to which the destination belongs on the backbone network as the destination node address. If it is not in both tables, the frame is sent to the backbone network with the broadcast address as the destination node address and a media access control header attached, and the frame received from the backbone network via the backbone network interface is sent to the backbone network. Remove the media access control header and use CSMA/
a media access control conversion unit that transmits data to the CD bus;
Means for searching the own node terminal table for the source address of a frame received from the SMA/CD bus side, and additionally registering the source address in the own node terminal table if the source address is not found, and registering or registering the registered source address In a CSMA/CD bus bridge composed of a backbone network and a node that has means for deleting from the own node terminal table terminal addresses for which the next search is not performed even after a certain period of time has passed since the search, in the own node terminal table, When the address of a terminal that has started sending packets is newly registered, or the address of a terminal that has finished sending packets is deleted, there is a means to send the changed contents to other nodes via the backbone network, and the other nodes A CSMA/CD bus bridge, characterized in that each node has a means for updating the contents of the corresponding node in the other node terminal table with the received change contents upon receiving the change contents of the own node terminal table of that node from the CSMA/CD bus bridge.