JPH04273735A - Local area network bridge device - Google Patents

Abstract

PURPOSE:To block the inflow of unrequired packetized data from one local area network to the local area network of another system. CONSTITUTION:A filter circuit 15 extracts the destination terminal address of a multiple address packet received from a first local area network 11, and deletes the multiple address packet when the address is registered on a filtering address memory circuit 17, and transfers it to an address learning circuit 16 when it is not registered. The address learning circuit 16 registers the destination terminal address of the multiple address packet on the filtering address memory circuit 17, and also, delivers the multiple address packet to a second local area network 12. Also, when the transmission destination of the multiple address packet is known, a transmission destination address is inputted from an input/ output device 22. An inputted address is registered on the filtering address memory circuit 17 via an input/output control circuit 21.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local area network bridge device for connecting local area networks.

0002

2. Description of the Related Art A so-called local area network (hereinafter referred to as LAN) is widely used as a form of data communication. This network is a network with excellent expandability and responsiveness that is constructed by organically linking computers and various terminals installed mainly within the same building, factory, university, or research facility. Therefore, due to its expandability, it is easy to connect and communicate with other LANs, public line networks, etc. For example, to connect two LANs, a bridge device is provided between them to relay data communication.

0003

[Problem to be Solved by the Invention] By the way, in such networks, data is usually communicated in packet format, but this is especially true when searching for resources within the network or when notifying all terminals within the network. Sometimes, broadcast communication using so-called broadcast packets is often performed. However, as mentioned above, for example, if two LANs
When building a network system by interconnecting LANs, conventional bridge devices relay all packet data input from one LAN to the other LAN, so even if the terminals on the own LAN Even if you want to perform broadcast communication only to other LANs,
Broadcast packets also flow into the network. Therefore, when viewed from a LAN of another system, there is a drawback that unnecessary processing such as reception increases due to the influx of packet data unrelated to the own system, and the throughput of the system decreases.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a local area network bridge device that can prevent unnecessary packet data from flowing in when performing packet data communication between a plurality of local area networks. .

[0005]

[Means for Solving the Problems] The invention according to claim 1 provides: (i) address extraction means for extracting a destination terminal address from packet data received from one local area network; and (ii) this address extraction means. (iii) when the destination terminal address of packet data received from one local area network matches the terminal address stored in the terminal address storage means, terminal address storage means for storing the extracted terminal address; and a selection means for discarding the data and transmitting the packet data to another local area network when there is no match.

According to the first aspect of the invention, each time packet data is received from one local area network, the destination terminal address is checked, and packets registered in the terminal address storage means are discarded. If the destination terminal address is not registered, it is transmitted to another local area network and the destination terminal address is additionally registered in the terminal address storage means.

According to the second aspect of the invention, the local area network bridge device according to the first aspect is provided with input means for inputting an arbitrary terminal address to be stored in the terminal address storage means.

[0008] According to the second aspect of the invention, when the destination terminal address within one local area network is known in advance, this is inputted from the input means and registered.

[0009]

EXAMPLES The present invention will be explained in detail with reference to Examples below.

FIG. 1 shows a local area network bridge device in one embodiment of the present invention. As shown in this figure, a first local area network 11 and a second local area network 12 are connected via a bridge device 13. This bridge device 13 is equipped with a filter circuit 15, whose input side is connected to the first local area network 11, and whose output side is connected to the second local area network 12 via an address learning circuit 16. ing.

The filter circuit 15 and address learning circuit 16 are connected to a filtering address storage circuit 17. These filter circuits 15 and address learning circuit 1
6 and the filtering address storage circuit 17 are connected to a control circuit 18 to perform various controls. This control circuit 18 is connected to an externally provided input/output device 22 via an input/output control circuit 21.

The operation of the local area network bridge device configured as above will be explained. Here, as an example, it is assumed that a broadcast packet in the format shown in FIG. 2 is sent from a terminal (not shown) in the first local area network 11.

As shown in FIG. 2, this broadcast packet is
It consists of a start flag 24 indicating the beginning of the packet, an end flag 25 indicating the end of the packet, and a destination terminal address 26, a source terminal address 27, a data section 28, and a control section 29 provided between these flags. Among these, the destination terminal address 26 and the source terminal address 27
indicate the address of the destination terminal and the address of the source terminal, respectively. Further, the control unit 29 indicates various control information necessary for transmission and reception.

A broadcast packet sent from a certain terminal within the first local area network 11 is received by the terminal indicated by the destination terminal address 26, and predetermined processing is performed. This terminal sets the address of the next terminal as the destination terminal address 26 in accordance with a predetermined circulation order and sends it out. Thereafter, similar processing is performed at each terminal within the first local area network 11.

[0015] Such a broadcast packet is sent to the bridge device 1.
3, the signal is first input to the filter circuit 15. Under the control of the control circuit 18, the filter circuit 15 extracts a destination address from the destination terminal address 26 of the input broadcast packet, and compares this with the address registered in the filtering address storage circuit 17. If this destination address matches any of the addresses in the filtering address storage circuit 17, this broadcast packet is discarded, and if they do not match, it is sent to the address learning circuit 16.

Under the control of the control circuit 18, the address learning circuit 16 extracts the destination address from the input broadcast packet, writes it into the filtering address storage circuit 17, and then transfers this broadcast packet to the second local It is sent to the area network 12.

Such processing is performed every time a broadcast packet is transferred from the first local area network 11. As a result, the first local area network 1 is stored in the filtering address storage circuit 17.
The addresses of the terminals that are the transmission targets in 1 will be accumulated in sequence. As a result, broadcast packets sent to a terminal having an address registered in the filtering address storage circuit 17, that is, a terminal in the first local area network 11, are sent to the filter circuit 1.
5, the inflow to the second local area network 12 is blocked.

[0018] Also, the destination terminal address 2 of the broadcast packet
6 may be input from the input/output device 22. In this case, the input destination terminal address 26 is registered in the filtering address storage circuit 17 via the input/output control circuit 21 under the control of the control circuit 18 . Other operations are the same as described above.

Although this embodiment has been explained using the example of registering the address of a broadcast packet, it goes without saying that the same processing can be performed even if the address is an individual terminal address or a group broadcast address. It is.

Furthermore, in this embodiment, transfer from the first local area network 11 to the second local area network 12 has been described, but transfer in the opposite direction can also be done by reversing the arrangement of the circuits. Similar processing can be performed.

[0021]

As explained above, according to the invention set forth in claim 1, the destination terminal address of packet data received from one local area network is checked, and the destination terminal address of packet data received from one local area network is checked. In this case, it is decided to prevent transmission to other local area networks, so it is possible to mutually prevent unnecessary packet data from flowing between a plurality of local area networks. Therefore, there is no need for each local area network to perform reception processing of unnecessary packet data, etc., and it is possible to prevent a decrease in the throughput of the entire system and the occurrence of failures due to overload.

Further, according to the invention as claimed in claim 2, since the destination terminal address of the packet data is entered and registered in advance from the input means, it is possible to completely prevent the packet data from flowing into other systems. It has the effect of being able to.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a local area network bridge device in one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the structure of a broadcast packet.

[Explanation of symbols]

11 First local area network 12 Second local area network 13 Bridge device 15 Filter circuit 16 Address learning circuit 17 Filtering address storage circuit 18 Control circuit 21 Input/output control circuit 22 Input/output device

Claims (2)

[Claims] 1. Address extraction means for extracting a destination terminal address from packet data received from one local area network; terminal address storage means for storing the terminal address extracted by the address extraction means; When the destination terminal address of packet data received from the area network matches the terminal address stored in the terminal address storage means, the packet data is discarded, and when it does not match, the packet data is transferred to another local area network. 1. A local area network bridge device comprising: selection means for sending data to a local area network. 2. The local area network bridge device according to claim 1, further comprising input means for inputting an arbitrary terminal address to be stored in the terminal address storage means.