JPH01259646A - Bridge device for complex local area network - Google Patents

Abstract

PURPOSE:To prevent the risk that a communication node is made into a down condition due to receiving the communication packet of a wrong destination address by the communication node by providing a transmission source address extraction means and a transmission source address comparison means. CONSTITUTION:The addresses (01)-(03) of bridge devices 131-133 and port addresses (1) and (2) are extracted from the transmission source address in the communication packet to be transmitted from an own slave local area network to the bridge devices 131-133, the address of the bridge devices and a port address are respectively compared with the address of an own bridge device and the address of the port receiving the communication packet and the communication packet is extinguished when both or either one is found to be different. Thus, the wrong bridge device address in the transmission source address or the communication packet having the port address are no longer transferred to a destination communication node and the risk that the communication node is led into the down condition by the return communication packet of the wrong destination address is completely prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bridge device for a complex local area network.

[Conventional technology]

One of the features of ring-type local area networks and bus-type local area networks is that multiple communication nodes connected to the same transmission path can perform N-to-N communication. Therefore, communication packets flowing on the transmission path have their address fields It holds both the destination address and the source address, making it clear from which communication node the packet was sent and to which communication node it should be sent. The addresses used in the above-mentioned composite local area network include the physical address part of the bridge device in the parent local area network and each of the multiple communication nodes connected to the child local area network connected to the bridge device. Generally, it consists of an address part that can be uniquely identified.

Conventionally, this type of composite local area network bridge device has been configured to send communication packets transmitted from a child local area network to the parent local area network of the destination bridge device to which the communication packet is to be sent from the destination address. All that was required was to extract the physical address at the address and transfer the communication packet to the destination bridge device using the address. In this process, it is checked whether the physical address of the extracted destination bridge device is the same as its own physical address, and if it is,
Since the communication packet is transferred from a communication node connected to a child local area network connected to the bridge device to another communication node connected to the same child local area network, the received communication Although it included a processing mechanism for discarding packets, there was no processing mechanism for extracting and verifying the physical address of the bridge device from the source address.

[Problem to be solved by the invention]

The conventional bridge device described above determines whether the physical address and port address of the bridge device in the source address of a communication packet are the same as the physical address of the bridge device itself and the address of the port that received the communication packet. Since verification is not performed, even if the physical address part or port address part of the bridge device of the source address in the communication packet sent from the communication node connected to the child local area network is incorrect, if only the destination address is correct, The communication packet reaches the destination communication node, and the communication node that receives the communication packet uses the source address that has the incorrect physical address or port address of the bridge device in the communication packet as the destination address of the return communication packet. Then,
This return communication packet will be returned to the wrong communication node. Therefore, in such a case, the communication node that receives this unexpected return communication packet may go down in the worst case, depending on how the error recovery function of the communication node is created. There is.

[Means to solve the problem]

The bridge device of a composite local area network of the present invention has a source address that extracts the address of the bridge device and the port from the source address present in a hierarchical address format in a communication packet transmitted from its own local area network. an extraction means, which compares the extracted address of the bridge device and port with the address of the own bridge device and the port that received the communication packet, and if at least one of the two is the same, deletes the communication packet; , has source address comparing means that transfers control to destination address checking means if both are the same.

[Operation J: Extract the address and port address of the bridge device from the source address in the communication packet transmitted from the own local area network to the bridge device, and use the address and port address of the bridge device as the address and port address of the own bridge device. This communication packet is compared with the address of the port that received it, and if either or both are the same, this communication packet is deleted.
Communication packets with an incorrect bridge device address or port address in the source address will no longer be forwarded to the destination communication node, and therefore communication packets with an incorrect destination address will be returned based on the incorrect source address. , there is no possibility that the communication node will go down due to the returned communication packet with the incorrect destination address.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a bridge device for a composite local area network (hereinafter referred to as LAN) of the present invention, and FIG. 2 is an overall configuration of a composite LAN including the bridge device of FIG. 1. 3(a) is a format diagram of a communication packet for transmitting information between communication nodes, and FIG. 3(b) is a hierarchical type diagram of each destination address and source address in FIG. 3(a). A format diagram showing the configuration. FIG. 4 is a format diagram of a communication packet with a correct source address from communication node 14+l in FIG. 2 to communication node 1422. FIG. 6 is a flowchart showing the operation of the source address check mechanism 109 in FIG. 1, and FIG. 3 is a flowchart showing the operation of the destination address check mechanism 110.

This composite LAN is a ring-type LA, as shown in Figure 2.
Parent L A N 11 which is N and child L A N 12 which is bus type LAN r, 12+a, 12□1,12
□2.123+.

1232, child LAN12++ and 12B, child LA
N 12□1 and 12ai, child L A N 123
bridging devices 13+, 13*, 133 connecting each pair of t and 12,2 to the parent L A N 11 via two ports 101, 102, respectively, and the child L A N
12++, 1211.1221.12□112s+
, 14th communication node connected to 1232,
1412.14□1゜14゜, 1431.14sz
Addresses "Ol", "02", and "03" for distinguishing the bridge devices 131.13z and 13s within the parent LAN 11, respectively, and the respective bridge devices 13+, 13g, and 13s (7) Address "l" to distinguish between two ports 101 and 102,
Communication nodes 141, 142 and 143 communicate with each other using hierarchical addresses consisting of "2" and address "001" for specifying communication nodes 1'S++ to 1432 in child L A N 12+r to I232, respectively. Perform packet communication.

As shown in Figure 3(a), the format of a communication packet consists of a destination address, a source address, and a data section.
The destination address and source address are shown in Figure 3(b).
As shown in , it consists of a bridge device address section, a port address section, and a communication node address section for the destination or source. Each bridge device 13. ~13. Ports 101 and 102 are bus type LAN transmitting and receiving mechanisms, and each has two child LANs 12.1 and 12+a, 1
2□, and 12□t+ 12s+ and 12,2 are connected. A bus-type LAN reception buffer 103 and a bus-type LAN transmission buffer 104 hold communication packets transmitted and received via the port 101. Bus type LAN reception buffer 1
05 and bus type LAN transmission buffer 106 are connected to port 102.
Holds communication packets sent and received via. The reception port address holding mechanism 107 holds the port address of the received port 101 or 102 when a communication packet is input to the reception buffer 103 or +05. The self-bridge device address holding mechanism 10B stores the bridge device 13.B to which it belongs. -133 is held. The source address check mechanism 109 verifies whether the source address present in the input communication packet is correct, and if it is incorrect, it decides to discard the communication packet, and if it is correct, it determines the destination address. The destination address check mechanism 110 passes control to the address check mechanism +10, checks the destination address of the received communication packet, and transfers the communication packet to the parent LAN.
Should the communication packet be transmitted to the child LAN 12□ to 1232, which is different from the child LAN 12+I-12st to which the communication packet has been transmitted, or should the communication packet be discarded? Decide on the strength. The bus type LAN reception packet discard mechanism 111 discards communication packets determined to be discarded by the source address check mechanism 109 or the destination address check mechanism 110, and
05 into a state ready to receive the next communication packet. The bus-type inter-LAN routing processing mechanism 112 uses the destination address checking mechanism 110 to determine whether the bus-type inter-LAN routing processing mechanism 112 is connected to another self-LAN 12 . ．． ~
12,2 is transferred from the receive buffer 103 or 105 to the transmit buffer 106 or 104.

Port 102 or 101 takes this out and sends it to its child LA.
Send to N12z to 123□. The ring type LAN transmission processing mechanism +13 moves communication packets determined by the destination address checking mechanism 110 to be transmitted onto the parent LAN II from the reception buffer 103 or 105 to the ring type LAN transmission buffer 115. Ring type L
The AN transmitting/receiving mechanism 116 sends this communication packet to the parent LA.
Send to the N II or take in communication packets from the parent LAN 11. The ring type LAN reception buffer 114 is
From the parent LAN 11 to the ring type LAN transmitting/receiving mechanism 11
The communication packet input via 6 is held.

The destination address of the communication packet shown in Figure 4 is "02-2"
-0 old". The first "02" indicates the bridge device 13□, the next "2" indicates its port 102, and the next "0 old" indicates the port connected to the board [02]. L
A communication node 142□ on A N 12□2 is shown. The breakdown of the sender address “Old-1-001” is “Ol
” indicates the bridge device 131, and the next “l” indicates its port +
01 respectively, and the next "0 old" indicates the communication node 1 on the child LAN 12++ connected to that port 101.
4.1 is shown. Figure 5 shows that the port address part of the source address of the communication packet shown in Figure 4 is correct.
1" is now "2", which indicates that this is the address of communication node 14+i and is incorrect.

Next, FIG. 6 shows a part of the operation of this embodiment.

Referring to the flowchart of FIG. 7, communication node 14.
1 to the communication node 1422 will be explained.

The communication packet transmitted from the communication node 14z is input to the bus-type LAN reception buffer 103 via the port 101 of the bridge device 131, and at the same time, the reception port address holding mechanism 107 receives a port address "1" indicating that the port lot has received the communication packet. is stored. Next, the source address check mechanism 109 checks the received communication packet.

(1) If the source address of the communication packet is incorrect, the source address check mechanism 109 checks "Ol" in the bridge device address field from the source address of the communication packet (FIG. 5) in the bus type LAN reception buffer 103. Extract (step 61). Next, the bridge device 13. is held in the own bridge device address holding mechanism 108. Compare the address "Ol" with the address "Old" just extracted (step 62), and since they are the same, extract "2" in the port address part from the source address (step 63), and retain the receiving port address. Mechanism 107
The previously stored "1゛°" is compared with the just extracted "2" (step 64), and since they are not the same, it is determined that this is not the correct source address, and the control is discarded for the bus type LAN received packet. The bus-type LAN received packet discard mechanism 111 transfers the received packet to the bus-type L
The communication packet received by the AN reception buffer 103 is discarded. Therefore, this communication packet is sent to the bridge device 1.
If the source address shown in FIG. 5 is "02-1-0 old", the source address check mechanism 109 extracts it as the own bridge device address. The communication packet is decided to be discarded because it is different from the address of the bridge device that was sent (step 62).
, this communication packet disappears in the same way as in the case described above.

(2) If the source address of the communication packet is correct, the source address check mechanism 109 extracts "old" in the bridge device address part from the source address of the received communication packet (FIG. 4) (step 61). Next, compare the address "Ol" of the bridge device +31 held in the own bridge device address holding mechanism 108 with the address "Ol" just extracted (Step 62), and since they are the same, the port address is further compared with the source address. 1” is extracted (step 63), and the °°l” previously stored in the reception port address holding mechanism +07 is compared with the just extracted “l” (step 64), and as a result, they are the same. It is determined that this source address is correct, and control is passed to the destination address checking mechanism 110 to terminate the process.

The destination address check mechanism +10 that has been given control checks the communication packet (fourth
"0" in the bridge device address part from the destination address in Figure).
2” is extracted (step 71).

Next, the bridge device 13. is held in the own bridge device address holding mechanism 108. Compare the address "Ol" with the address "02" just extracted (step 72),
Since they are not the same, this communication packet is the parent L A N 11
It is determined that the communication packet should be sent to the ring type LAN transmission processing mechanism 113, and the process is terminated. The ring-type LAN transmission processing mechanism +13 stores this communication packet in the ring-type LAN transmission buffer 115, and the ring-type LAN transmission and reception mechanism! 16 takes out this communication packet from the ring type LAN transmission buffer 115 and sends it to the parent LA.
Send to N+1. If the destination address shown in FIG. 4 is not "02-2-001" but communication node 14.
□If it is "01-2-001" indicating the destination, the determination result of the address in the bridge device address part is the same (step 72), and then "2" in the port address part is extracted from the destination address (step 73), the “l” held in the receiving port address holding mechanism 107 and the just extracted “2” are compared, and since the results are not the same, this is the case from the port 101 to the port 102, that is, the child L AN 121. Karako L A N 12+2
It is determined that the communication packet should be transmitted to the bus type LA.
Control is passed to the N-to-N routing processing mechanism 112 and the processing is terminated. Bus type inter-LAN routing processing mechanism 112
stores the communication packet in the bus-type LAN transmission buffer 106, and the port 102 takes out this communication packet and sends it to the child L.
Send to AN1412.

(3) If the destination address is incorrect If the destination address is incorrect, the communication node 1411
If the own address is "01-1-0 old", the destination address check mechanism 110 determines to discard this communication packet because the receiving port address is equal to the extracted destination port address (step 74), and the destination address check mechanism 110 determines to discard this communication packet. Control is passed to the received packet discard mechanism I11 and the process ends. The bus-type LAN received packet discard mechanism llll discards this communication packet input to the receive buffer 103.

〔Effect of the invention〕

As explained above, in the present invention, the bridge device checks even the source address of communication packets flowing in from the child local area network, and the bridge device address part of the source address matches the own bridge device address. If the specified address is not correct, the communication packet will be deleted. Also, if the port address part of the source address is different from the address of the port to which the communication packet was input, the communication packet will be deleted. prevent communication packets with the same source address from being forwarded to the destination communication node,
Conventionally, a communication node that receives a communication packet with an incorrect source address creates and returns a communication packet with that address as the destination address, without knowing that it is an incorrect address, and sends it back. Since the communication node is not returned to a child local area network other than the child local area network to which the communication node belongs, there is no risk that the communication node will go down due to receiving a communication packet with an incorrect destination address. In a test where a test packet is sent out for the purpose of confirming the connection of the other party, the destination address and source address of the packet are exchanged and sent back, and the operator inputs the own communication node address. It has a particularly useful effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a bridge device for a composite LAN according to the present invention, FIG. 2 is an overall configuration diagram of a composite LAN including the bridge device of FIG. 1, and FIG. Format diagram of communication packets for transmitting information, Figure 3 (
b) is a format diagram showing the hierarchical structure of each destination address and source address in Fig. 3 (aJ);
A format diagram of a communication packet with a correct source address from the communication node 14□ to the communication node 14□2 in the figure.
A format diagram of a communication packet sent to 4□2 with an incorrect source address, FIG. 6 is a flowchart showing the operation of the source address check mechanism 109 in FIG. 1, and FIG. 3 is a flowchart showing the operation of the destination address check mechanism 110. +1・・・・・・・・・Parent LAN. 1211-12,2... Child LAN. 13, ~13. ...Bridge device, +411-1
43□...Communication node, 101, 102...
Own port, 103, 105...Bus-type LAN reception buffer, 104, 106...Bus-type LAN transmission buffer, +07...Reception port address holding mechanism, 108... Own bridge device address holding mechanism, +09... Source address checking mechanism, 110.
...Destination address check mechanism, II+...Bus type L
AN received packet discard mechanism, +12...Path type LAN
Inter-routing processing mechanism, 113...Ring type LAN
Transmission processing mechanism, 114...Ring type LAN reception buffer, 115...Ring type LAN transmission buffer, 116
...Ring type LAN transmission/reception mechanism, 61~64.71~
74...Step.

Claims (1)

[Claims] 1. A parent local area network, a plurality of child local area networks, and a plurality of child local area networks that connect the plurality of child local area networks to the parent local area network through a plurality of ports corresponding to each of the child local area networks. An address portion that distinguishes each bridge device within the parent local area network, and an address portion that distinguishes each port in each bridge device, comprising a bridge device and a plurality of communication nodes connected to each child local area network. In a bridge device for a composite local area network that performs packet communication with each other between multiple communication nodes using a hierarchical address consisting of an address part that distinguishes each communication node in each child local area network, source address extraction means for extracting the addresses of the bridge device and the port from the source addresses present in the hierarchical address format in the communication packet transmitted from the communication packet; Comparing the addresses of the bridge device and the port that received the communication packet, and if at least one of them is the same, the communication packet is deleted, and if both are the same, the control is transferred to the destination address checking means. A bridge device for a composite local area network, comprising source address comparison means.