JPH01181255A - Bridge device - Google Patents

Abstract

PURPOSE:To allow the device to cope flexibly with the system change and to reduce the overhead at packet transmission by updating the content of a routing table based on a terminal number of a sender included in a packet signal. CONSTITUTION:When a terminal equipment T12 sends a packet signal and it is inputted to a bridge device B1, the bridge device B1 gives a sender terminal number 0B to the 1st symbol string collation memory M1 and the 2nd symbol string collation memory M2 via a patch D1. When the content of the 1st symbol string collation memory M1 only is coincident, a routing table is not updated. Moreover, when the content of the 2nd symbol string collation memory M2 only is coincident, the relevant terminal number is deleted from the memory M2 and registered in the memory M1. When the content of both the memories M1, M2 is coincident, the relevant sender number is deleted from the memory M2. When the content of both the memories M1, M2 is dissident, the number of the memory M1 is registered in a registration address 01.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applied to a bridge device for a complex local area network. In particular, it relates to means for generating a routing table.

〔overview〕

The present invention provides system change by updating the contents of the routing table based on the source terminal number included in the packet signal in a routing table generation means for a packet transmission system consisting of a sublocal area network and a backbone local area network. It is possible to deal with this situation flexibly and reduce the overhead during packet transfer.

[Conventional technology]

Conventionally, fixed assignment is not used in the means for generating the routing table of a bridge device in a composite local area network consisting of a sublocal area network connecting terminals and a backbone local area network connecting multiple sublocal area networks. There are means and learning means. Fixed assignment is achieved by storing in advance in all bridge devices a routing table that associates all terminal numbers with node numbers on the backbone local area network of the bridge device that accommodates the terminals. In addition, in the learning generation means, each bridge device compares the source terminal number of the packet passing through the bridge device with the terminal number stored in the routing table, and if it is not registered in the routing table, it is registered. , does not change the routing table if it is registered. In particular, by arranging the routing tables in descending or ascending order of terminal numbers, we can efficiently compare and match source terminal numbers with the routing tables based on search algorithms such as linear search and binary search. was. Furthermore, in either method, the routing table is configured on a general-purpose memory, and the operation of comparison and verification is realized by software using a general-purpose microprocessor.

[Problem that the invention seeks to solve]

With conventional fixed allocation methods for generating routing tables, when adding, moving, or deleting terminals, it is necessary to change the routing table each time and re-storing it to all bridges, making it inflexible. It has a flaw in its lack of sex. On the other hand, the learning generation means uses a general-purpose microprocessor and general-purpose memory to execute a search algorithm each time a packet passes through the bridge, so it has the disadvantage of increasing the overhead of packet transfer processing.

The present invention aims to eliminate these drawbacks, and aims to provide a bridge device that can flexibly respond to system changes and perform routing without increasing the overhead of packet transfer processing.

[Means for solving problems]

The present invention is provided at a connection point between a local area network and a plurality of sublocal area networks to which terminals assigned terminal numbers are connected, through which a packet signal including a source terminal number passes, and a node number is assigned. The bridge device that has been configured has a storage area for registering the terminal numbers of the terminals connected to the sublocal area network connected to the bridge device, and the terminal number that matches the terminal number included in the packet signal is registered. A first memory that sometimes generates a first coincidence signal, and a storage area that registers terminal numbers of terminals connected to a sublocal area network coupled to other devices, and includes a terminal included in a packet signal. a second memory that generates a second matching signal when a terminal number matching the number is registered and an address signal indicating an address of a storage area in which this terminal number is registered; and an address indicated by the address signal. a third memory that registers the node number of the device to which the terminal to which the terminal number registered in the storage area is connected is registered in the storage area to which the address corresponding to the address indicated by the address signal is attached; The source terminal number included in the packet signal from the area network is given to the first and second memories, and this is based on the combination of the presence or absence of the first and second matching signals from these two memories. a first updating means for updating the registered contents of the two memories; and a first updating means for updating the registered contents of the two memories; and a first updating means for updating the registered contents of the two memories; and a second updating means for updating the registered contents of the two memories and the third memory based on a combination of the presence or absence of the second coincidence signal.

[Effect]

A source terminal number included in a packet signal arriving from the sublocal area network side is given to first and second memories. When a matching signal is generated in the first memory and no matching signal is generated in the second table, the routing table is not updated. When the first memory does not generate a coincidence signal and the second memory generates a coincidence signal, this terminal number is deleted from the second memory and additionally registered in the first memory. When both the first and second memories generate matching signals, this terminal number is deleted from the second memory. Further, when neither the first memory nor the second memory generates a matching signal, this terminal number is additionally registered in the first memory.

The terminal number of the source included in the packet signal arriving from the local area network side is given to the first and second tables. generating a match signal in a first memory;
When a matching signal is not generated in the second memory, this terminal number is deleted from the first memory, additionally registered in the second memory, and the contents of the third memory are accordingly changed and registered. When a coincidence signal is not generated in the first memory and a coincidence signal is generated in the second memory, the third memory is updated if the source node numbers do not match, and is not updated if they match. When both the first and second memories generate matching signals, this terminal number is deleted from the first memory.

Further, when both the first and second memories do not generate a matching signal, this terminal number is additionally registered in the second memory, and accordingly, additionally registered in the third memory.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings. 1st
The figure is a schematic diagram showing the configuration of a routing table included in this embodiment device, and FIG. 2 is a block diagram showing the configuration of a composite local area network to which the embodiment device is applied.

As shown in Fig. 2, this composite local area network consists of three sub-local area network S1,
B2 and B3 and one backbone local area network R and sub local area network 5
Bridge device BISB connecting each of ISS2 and B3 to backbone local area network R
2 and B3, and each of the bridge devices B1, B2, and B3 has node numbers (01), (02), and (3) on the backbone local area network R.
) are attached to each of them. Terminals Tll and T12 are connected to sublocal area network S1, terminal T21 is connected to sublocal area network S2, and terminal Ts+J is connected to sublocal area network S3.
3 and T32 are connected. Here, terminal T0, TI!
, T21, T31, and T32 each have a terminal number (
OA), (OB), (OC), (OD) and (OE)
are given to each of them.

As shown in FIG. 1, the bridge device B1 in FIG.
a first symbol string matching memory M1, a second symbol string matching memory M2, a node number memory M3 and an updating means C1;
A routing table including C2 is provided. The first symbol string matching memory M1 stores the terminal numbers (
OA) and (OB) are registered, the terminal number to be compared and verified is given via path D1, and if it matches the registered terminal number, a match is displayed with the registered address D2 of the matched terminal number. A signal D3 is output. The second symbol string matching memo IJ M 2 is another bridge device B2
and terminals T 21 connected to sublocal area networks S2 and S3 of B3 %T31 and T3
The terminal numbers (OC), (OD), and (OE) of 2 are registered, and the terminal number to be compared is given via route D1. A registered address D4 of the terminal number and a match display signal D5 are output. In the node number memory M3, a bridge corresponding to the terminal number is stored in the memory address corresponding to the registered address of the terminal number (QC), (OD), and (OE) registered in the second symbol string collation memo IJM2. The node numbers (02) and (03) on the backbone local area network R of are registered. Here, the symbol string matching memory is composed of a sequential circuit and a memory, and is capable of registering at least one or more finite number of symbol strings, and is registered with a symbol string input sequentially from the outside in symbol units. All registered symbol strings are compared and verified at the same time, and when a match is found with any of the registered symbol strings, a match display signal and the registered address of the matched registered symbol string are output.

(“String Search LSIJ Institute of Electronics, Information and Communication Engineers Technical Research Report vo187cAs87-25 May 29, 1987) In other words, this embodiment registers the terminal number of the terminal connected to the sublocal area network connected to the own device. A first symbol string matching memo+JM1, which is a first memory having a storage area and generating a first matching signal when a terminal number matching a terminal number included in a packet signal is registered; , has a storage area for registering the terminal number of a terminal connected to a sublocal area network coupled to another device, and when a terminal number that matches the terminal number included in the packet signal is registered, the second A second symbol string matching memo IJM2, which is a second memory, generates a match signal and an address signal indicating the address of the storage area where this terminal number is registered, and the terminal number is registered in the storage area having the address indicated by the address signal. the node number memory M3, which is a third memory that registers the node number of the device to which the terminal to which the terminal number is attached is connected, in the storage area to which the address corresponding to the address indicated by this address signal is attached; The terminal number of the source included in the packet signal from the sublocal area network is given to the first and second memories, and the second memory is assigned based on the combination of the presence or absence of the first and second matching signals from these two memories. a first updating means C1 for updating the registered contents of two memories; and a first updating means C1 for updating the registered contents of two memories; and a second updating means C for updating the registered contents of the two memories and the third memory based on the combination of presence/absence of the second coincidence signal.
2.

Next, the operation of routing using a routing table will be explained. FIG. 3 is a format showing the structure of a frame of a packet signal transmitted from terminal T12 to terminal T31, with destination terminal number OD and source terminal number OB.
is attached to the data. The bridge device B1 sends the destination terminal number OD of this packet signal to the first symbol string matching memory M1 and the second symbol string matching memory 17 M2 via the path D1.
give to.

Since the terminal number OD is registered in the second symbol string matching memo IJM2, as a result of the matching operation, the first symbol string matching memo 'JMI does not output the match display signal D3,
The second symbol string matching memory outputs the registered address 02 of the terminal number that matches the match display signal D5. Next, based on the registered address 02 obtained as a result of the verification operation, the bridge device B1 refers to the address 0002 of the node number memory M3 corresponding to this registered address, and searches for the node number 0.
Get 3. The bridge device B1 adds the node number 03 of the bridge device B3 that accommodates the destination terminal number OD obtained in this manner and the node number 01 of its own bridge device B1 to the packet signal shown in FIG. A packet signal shown in is constructed and sent to the backbone local area network R to complete the routing operation.

The routing table generation operation includes an operation of generating a routing table from a packet signal input from a sub-local area network, and an operation of generating a routing table from a manually inputted packet signal from a backbone local area network.

First, the operation of generating a routing table from packet signals input from a sublocal area network will be explained. In the initial state, nothing is registered in the first symbol string matching memory M1, the second symbol string matching memory M2, and the node number memory M3 that constitute the routing table of the bridge device B1. Here, terminal T+□
transmits the packet signal shown in Fig. 3, and bridge device B
1. The bridge device B1 sends the source terminal number OB of the input packet signal to the first symbol string matching memory M1 and the second symbol string matching memory IJM via the path D1.
Give to 2. The bridge device B1 outputs a match display signal D3 obtained as a result of the matching operation of the two symbol string matching memories.
and D5 for the routing table.
Perform the actions shown in the table.

That is, if only the first symbol string matching memory M1 outputs the matching signal D3, the corresponding source terminal number has already been registered as a terminal connected to the bridge device Bl, and
Since it is not registered as a terminal connected to other bridge devices B2 and B3, the routing table is not updated. If only the second symbol string matching memory M2 outputs the matching signal D5, the corresponding terminal transmits data even though the corresponding transmission source terminal number is registered as a terminal connected to another bridge device B2 or B3. Since it is the original
It is connected to bridge device B1. That is, the corresponding terminal is connected to the sub-local area network S1 of the bridge device B1 from the other bridge device B2 or B3.
Indicates that you have moved to . In this case, the corresponding terminal number is deleted from the second symbol string matching memory M2 and registered in the first symbol string matching memo IJM1. The first symbol string matching memory M1 and the second symbol string matching memory M2 generate a match signal D.
If both 3 and D5 are output, the corresponding terminal is registered as a terminal connected to bridge device B1, and this terminal is also registered as a terminal connected to other bridge devices B2 or B3. It is. In other words, the routing table is inconsistent. In this case, the inconsistency is resolved by deleting the corresponding source terminal number from the second symbol string matching memo 'JM2. If neither the first symbol string matching memory M1 nor the second symbol string matching memory M2 outputs a matching signal, this indicates that the corresponding source terminal number is unregistered. In this case, the corresponding terminal number is registered in the first symbol string matching memory M1. That is, when the bridge device receives the packet signal shown in FIG. 3, the first symbol string matching memory Ml and the second symbol string matching memory M2
is the initial state, and since neither the first symbol string matching memo 'JMI' nor the second symbol string matching memo 'JM2 outputs a matching signal, the corresponding source terminal number OB is the first symbol string matching memo 'JMI'. It is registered to the registration address 01 of the memo IJM1. The state after registration is shown in FIG.

Next, the operation of generating a routing table from packet signals input from the backbone local area network will be explained. First symbol string matching memory M1 that constitutes the routing table of bridge device B3
, second symbol string matching memory M2 and node number memory M3
is the initial state and nothing is registered. here,
When the packet signal shown in FIG. 4 sent from the bridge device B1 to the backbone local area network R is manually input to the bridge device B3, the bridge device B3 transmits the source terminal number OB of the manually input packet signal via the path D1. It is applied to the first symbol string matching memory Ml and the second symbol string matching memory 'IM2.

The bridge device B3 performs the operations shown in Table 2 on the routing table based on the matching display signals D3 and D5 obtained as a result of the matching operation of the symbol string matching memory.

(Hereinafter, this page margin) In other words, if only the first symbol string matching memo 'JMI outputs the matching signal D3, the corresponding source terminal number has already been registered as a terminal connected to its own bridge device B3, and It is in a state where it is not registered as a terminal connected to other bridge devices B1 and B2. That is, this indicates that the corresponding terminal has moved from its own bridge device B3 to the sublocal area network of another bridge device B1 or B2. In this case, the corresponding source terminal number is deleted from the first symbol string matching memory M1, registered in the second symbol string matching memo IJM2, and the address of the node number memory M3 corresponding to the registered address is saved. Register the source node number of the packet signal. Second symbol string matching memo 'J
If only M2 outputs the matching signal D5, the corresponding source terminal number is bridge device B1 other than own bridge device B3.
Or, it has already been registered as a terminal connected to B2.

In this case, the node number registered at the address of the node number memory M3 corresponding to the registered address D4 of the second symbol string matching memo 17 M2 that outputs this match display signal D5 and the input packet signal are transmitted. Compare with the original node number. As a result, if the two agree,
The routing table is not updated, and if there is a mismatch, it indicates that the terminal connected to the sublocal area network of another bridge device has moved to a different bridge device, so the node number memo IJ M
The node number registered in address 3 is changed to the source node number of the input packet. First Book 1
When the code string matching memory M1 and the second symbol string matching memory M2 output matching display signals D3 and B5, respectively, the corresponding transmission source terminal is registered as a terminal connected to the bridge device B3, and furthermore, the terminal is registered as a terminal connected to the bridge device B3. is also registered as a terminal connected to another bridge device B1 or B2.

In other words, the routing table is inconsistent.

In this case, the inconsistency is resolved by deleting the corresponding source terminal number from the first symbol string matching memory M1. If neither the first symbol string matching memo 'JMI nor the second symbol string matching memory M2 outputs a matching signal, this indicates that the corresponding source terminal number is unregistered.

In this case, the corresponding source terminal number is registered in the second symbol string matching memory M2, and the source node number of the human-powered packet signal is registered in the node number memory address corresponding to the registered address. That is, bridge device B3 is the fourth
When the packet signal shown in the figure is received from the backbone local area network R, the first symbol string matching memo I
Since neither JM1 nor the second symbol string matching memory M2 outputs a matching signal in the initial state, the bridge M3 registers the corresponding source terminal number OB to the registration address 01 of the second symbol string matching memory. . Furthermore, address 000 of node number memory M3 corresponding to this registered address 01
1, the old source node number of the corresponding packet signal is registered. The state after registration is shown in FIG.

Each bridge device autonomously generates a routing table by performing such a routing table generation operation on all packet signals passing through the bridge device.

〔Effect of the invention〕

As explained above, the present invention can more flexibly respond to the addition, movement, and deletion of terminals than the conventional fixed allocation method of routing tables, and can perform the search algorithm using conventional general-purpose memory. This method has the effect of reducing overhead during packet transfer compared to other methods.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing the configuration of a routing table included in an embodiment of the present invention. FIG. 2 is a block configuration diagram showing the configuration of a system to which an embodiment of the present invention is applied. FIG. 3 is a format diagram showing the structure of a packet signal on a sublocal area network. FIG. 4 is a format diagram showing the structure of a packet signal on a backbone local area network. FIG. 5 and FIG. 6 are explanatory diagrams showing the process of creating a routing table. Ml...first symbol string matching memory, M2...second symbol string matching memory, M3...node number memory, C1
, C2...updating means, Dl...verification data input route, B2, B4...registered address, B3, B5...-
Number display signal, Sl, B2, B3... Sub local area network, R... Backbone local area network, B1, B2, B3... Bridge device,
'I'll, TI2, Ta2, T31, T32... terminal. Patent applicant: NEC Corporation 4-2 Agent: Patent attorney Nao Takashi Ide'. °“・-- Diagram N1 System configuration including the embodiment Fig. 2 Packet signal structure Fig. 3 Packet signal structure Fig. 4 Operation of the embodiment Fig. 5

Claims (1)

[Scope of Claims] 1. Provided at a connection point between a plurality of sublocal area networks and a local area network to which terminals assigned terminal numbers are connected, and through which a packet signal including a source terminal number passes, A bridge device with a node number has a storage area for registering the terminal number of a terminal connected to a sublocal area network connected to the bridge device,
a first memory (M1) that generates a first matching signal when a terminal number that matches the terminal number included in the packet signal is registered; and a first memory (M1) that is connected to a sublocal area network that is coupled to other devices. It has a storage area for registering the terminal number of a terminal, and when a terminal number that matches the terminal number included in the packet signal is registered, a second matching signal and the address of the storage area in which this terminal number is registered are sent. a second memory (M2) that generates an address signal indicated by the address signal; and a second memory (M2) that generates an address signal indicated by the address signal; The third memory (M3) is registered in the storage area with the address corresponding to
), the source terminal number included in the packet signal from the sublocal area network is given to the first and second memories, and the combination of the presence or absence of the first and second matching signals from these two memories is performed. a first updating means (C1) for updating the registered contents of these two memories based on the above; and second updating means (C2) for updating the registered contents of the two memories and the third memory based on a combination of the presence or absence of the first and second coincidence signals from the two memories. bridge device.