JPH087728B2 - Address discriminator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an address discriminating device used for a LAN connecting device or the like provided when connecting two LANs.

[0002]

2. Description of the Related Art In a LAN connecting device, one LAN-A
In order to transfer the frame containing the data from the terminal accommodated in 1 to the terminal accommodated in the other LAN-B, the address discriminating device checks the destination address contained in the received frame and performs processing based on the check result. Device is L
Only the received frame including the address of the terminal accommodated in AN-B is transferred to LAN-B. A device described in Japanese Utility Model Laid-Open No. 01-153750 is known as a device for determining this address.

The address discriminating apparatus described in this publication includes an address register in which a destination address extracted from a received frame is set, a local memory in which addresses of all terminals accommodated in a LAN of a connection destination are stored, Local CPU that checks whether the destination address in this address register is registered in the local memory
It consists of If the address that matches the destination address stored in the address register is registered in the local memory, the local CPU notifies the CPU of the processing device of a control signal for transferring the received frame to LAN-B. are doing.

[0004]

In the above-mentioned conventional address discriminating apparatus, since the received frame is discriminated by one local CPU, the number of terminals connected to the destination LAN increases and the number of addresses to be checked is increased. If the number of received frames becomes large, the received frame determination processing time for each received frame becomes long, and it takes a long time to transfer the received frames between LANs. The same problem also occurs when a large number of inter-LAN connecting devices are accommodated in the destination LAN.

The present invention explains the above-mentioned problems, and even if the number of terminals accommodated in the connected LAN increases, LA
It is an object of the present invention to provide an address discriminating apparatus capable of discriminating whether a received frame should be transferred between N or not.

[0006]

In this address discriminating device, a destination address of a frame to be transferred from one LAN to another LAN is provided in a LAN connecting device for connecting a LAN and another LAN. And (b) a local memory that is provided corresponding to this address register and that registers the terminal address accommodated in the transfer destination LAN. And (c) a local CPU which is provided corresponding to the address register and the local memory, and which compares and collates the address information registered in the local memory corresponding to the destination address written in the corresponding address register. N sets are provided, and the N local memories are provided with addresses of terminals accommodated in the transfer destination LAN. Are distributed and registered, and the local CPU that detects the same address as the terminal address stored in the corresponding address register in the corresponding local memory generates a control signal for transferring the frame to the transfer destination LAN. And

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the embodiments of the present invention, a system in which the address discriminating apparatus of the present invention is used will be described with reference to FIG.

In FIG. 2, LAN 30 includes LAN 31 and LA.
They are connected via the N connection devices 1 and 3 and the processing device 2. Further, in FIG. 2, the LAN 30 and the LAN 32 are connected via the LAN connection devices 14 and 16 and the processing device 15. By adding a LAN connection device and a processing device to the LAN 30, it is possible to connect to more LANs. The same applies to the LANs 31 and 32.
An arbitrary number of terminals are connected to each LAN.

From the terminal 21 accommodated in the LAN 32 of FIG.
The flow of a frame when a frame is transferred from a terminal connected to a LAN to a terminal connected to another LAN will be described by taking as an example the case of transmitting a frame to the terminal 17 accommodated in the AN 31. First, the frame output from the terminal 21 is passed to the LAN connection device 14 and is accumulated in the reception buffer built in the LAN connection device 14 via the LAN controller in the LAN connection device 14. Further, the local CPU in the LAN connection device 14 checks whether or not the destination address of this data frame is the address of the terminal accommodated in the LAN connected via the LAN connection device 1. Then, the frame stored in the reception buffer is passed through the processing device 15 to the LAN 3
0 is stored in the transmission buffer in the LAN connection device 16. The frames accumulated in the transmission buffer are passed through the LAN controller in the LAN connection device 16 to the LAN 3
Passed to 0. The data frame delivered to the LAN 30 is subjected to similar processing by the LAN connection device 1, the processing device 2 and the LAN connection device 3 and is delivered to the LAN 31 to be received by the terminal 17.

As described above, the processing for determining the destination address, which is conventionally performed in the LAN connecting device, is one local CP.
According to the present invention, the determination process is distributed to a plurality of N local CPUs and is processed in parallel in the present invention, so that the time required for the determination process of the destination address is shortened and the terminal connected to the LAN is connected. The feature is that the data transfer rate between LANs is not reduced even if the number of LANs connected to one LAN increases and the number of addresses to be checked increases as the number of LANs increases.

Next, an embodiment of the present invention will be described with reference to FIG. FIG. 1 includes an address discrimination device 12 which is an embodiment of the present invention. Details of the LAN connection device 14 and the processing device 15 are shown. In the LAN connection device 14, a reception buffer 9 for storing a reception frame, a transmission buffer 10 for storing a transmission frame, and a reception data frame from the LAN 32 when a frame is received from the LAN 32 are written in the reception buffer 9 and received. The destination address of the data frame is written in the address registers 6-1 to N, the local CPUs 7-1 to N are notified of the reception, and the processing device 15
When transmitting data from the LAN to the LAN 32, the LAN controller 11 for transmitting the data stored in the transmission buffer 10 to the LAN 32, N address registers 6-1 to N for storing the destination address of the received frame, and these Local C corresponding to each of N address registers
It is composed of PUs 7-1 to N and local memories 8-1 to 8-N provided respectively corresponding to these N local CPUs.

Each local memory has another LAN, FIG.
In the example, the addresses a, b, c. Of the terminals 17, 18, 19, 20. d and addresses e and f of the processing devices 2 and 15
Are distributed and registered.

Since there are N local memories, when registering in the local memory, the address information is allocated to the N local memories so as not to overlap as evenly as possible.

In order for the processing performance of the received data frame per LAN connection device 14 to satisfy the expected standard, the capacity per local memory is set to the local CPU.
Since it is necessary to keep the size below a certain size determined by the performance of 7-1 to N, the number of addresses that can be registered in one local memory is also determined. Therefore, the value obtained by dividing the total number of terminals connected to the network by the number of addresses that can be registered in one local memory is suitable for the system, within the range where the processing performance of each received frame is expected. Number of local memory,
That is, the number N of local CPUs.

A flow of processing when a frame is transmitted from the terminal 21 on the LAN 32 to the terminal 17 on the LAN 31 will be described with reference to FIGS. 1, 2 and 3. When the terminal 21 sends out the data frame of the destination address a to the LAN 32,
The data frame passes through the LAN 32 to the LAN connection device 14 and is temporarily stored in the reception buffer 9 via the LAN controller 11. At this time, the LAN controller 11 simultaneously writes the destination address of the received frame into all of the N address registers 6-1 to N,
All N local CPUs 7-1 to N are notified by broadcast that the data frame has been received. Upon receiving the notification, the N local CPUs 7-1 to N refer to the address registers 6-1 to N in each address comparison unit in the local CPUs 7-1 to N to refer to the local memories 8-1 to 8-1.
The address information registered in N is compared, and if they match, the CPU 5 of the processing device 2 is notified. If no matching address is found, the process is terminated without notifying anyone. Since the address information of the terminals connectable via the LAN connection device 14 is registered in the local memories 8-1 to 8-N without duplication, the reception notification to the CPU 5 is only one in the processing of one data frame. Only once or zero times. As shown in FIG. 3, since the destination address a of the data frame passed to the LAN connection device 14 is registered only in the local memory 8-N, only the local CPU 7-N notifies the processing device 15 of the reception. . Upon receiving this notification, the processing device 15 sends the data frames stored in the reception buffer 9 to the main memory 4
2 and writes it in the transmission buffer in the LAN connection device 16 of FIG. 2, and issues a transmission request to the LAN controller of the LAN connection device 16. Next, the transmission controller of the LAN connection device 16 sends the data frame stored in the transmission buffer of the LAN connection device 16 to the LAN 30.

In the same way that a data frame is sent from LAN 32 to LAN 30, LAN 30 to LAN 31
Also to LAN connection device 1, processing device 2, LAN connection device 3
The terminal 17 on the LAN 31 receives the data frame via the. By registering the destination addresses in the plurality of local memories in the distributed manner as described above, the number of addresses to be compared and collated by one local CPU can be reduced, and the address determination processing can be speeded up.

According to the present invention, when registering the address information in the address table of the local memory, the address information having a higher access frequency can be registered at a position where the address is searched earlier, for example, at a lower address of the local memory. In this embodiment, the more frequently a destination address is accessed, the more quickly a match is detected, so that the average address detection time is shortened.

FIG. 3 shows the N local memories 8-1 to 8-N existing in the LAN connection device 14.
1 to N show that the address information is distributed and registered without being evenly overlapped, and the registration position in the local memory is also made in consideration of the access frequency. In FIG. 3, it is assumed that the search is performed sequentially from the bottom, and consideration is given to registering the address information having a higher access frequency in the lower rank of the local memory. Here, the access frequency of b is higher than that of d and a is higher than that of e. Further, if the destination addresses having the same access frequency are stored in another local memory, further speedup can be achieved. As another embodiment, in order to reduce the load on the local CPU in the LAN connection device, it is possible to cut out a portion corresponding to the processing of the address comparison unit from each local CPU and provide a processor dedicated to the address determination.

[0019]

As described above, according to the present invention, a large number of terminals can be accommodated by distributing destination address information in a plurality of address tables and searching them in parallel by a plurality of local CPUs. Even if the number of registered addresses increases in a large-scale LAN, the frame transfer time of the LAN-to-LAN connecting device can be shortened.

[Brief description of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a diagram showing a network configuration example of a system.

FIG. 3 is a diagram showing an example of contents of a local memory.

[Explanation of symbols]

 1, 3, 14, 16 LAN connection device 2, 15 processing device 4 main memory 5 CPU 6-1 to N address register 7-1 to N local CPU 8-1 to N local memory 9 reception buffer 10 transmission buffer 11 LAN controller 12 Address discrimination device 17, 18, 19, 20, 21, 22 Terminal 30, 31, 32 LAN

Claims (2)

[Claims] 1. A local area network (LAN)
Is an address determination device that is provided in a LAN connection device that connects a LAN and another LAN, and that determines a destination address of a frame to be transferred from one LAN to the other LAN. Address register, and (b) a local memory provided corresponding to this address register for registering a terminal address accommodated in the transfer destination LAN, and (c) corresponding to the address register and the local memory. N sets of local CPUs, which are provided for each of the destination addresses written in the corresponding address registers and compare and collate the registered address information in the corresponding local memory, are provided.
The addresses of the terminals accommodated in the transfer destination LAN are distributed and registered in this local memory, and the local CPU that detects the same address as the terminal address stored in the corresponding address register in the corresponding local memory, An address discriminating apparatus, which generates a control signal for transferring the frame to a transfer destination LAN. 2. The address discriminating apparatus according to claim 1, wherein terminal addresses that are accessed more frequently are stored in the local memory addresses that are searched faster in the N local memories.