JPH0758770A - Multi-port repeater system - Google Patents

Abstract

PURPOSE:To protect important information by transmitting a frame only to a specific station. CONSTITUTION:This system is equipped with a filtering table 122 which registers the station addresses of stations 117-121 connected with plural input and output ports 131-135, and filtering discriminating parts 102-106 which operate filtering to the frames except the frames transmitted from the stations 117-121 having the station addresses registered in the filtering table 122, and the frames transmitted to the stations 117-121 having the station addresses registered in the filtering table 122.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiport relay device, and more particularly to a multiport relay device capable of transmitting a frame from a specific station to a specific station.

[0002]

2. Description of the Related Art A multi-port relay device is a very convenient device in which a number of stations connected to a network are concentrated because a plurality of stations can be connected via a plurality of input / output ports. Further, for example, a small-scale network can be constructed without using a coaxial cable such as Ethernet, and it can also be used for a small-scale personal computer LAN or the like.

In the following, IEEE 802.3 (CSMA
/ CD (Carrier Sense Multipl
e Access with Collision D
The above-mentioned multi-port relay device conforming to the above (e.g.

A multiport relay device 10 shown in FIG.
0 is a protocol processing unit 101 that detects frame collision and repeats the frame to each station, and input / output ports 131 to 13 connected to the protocol processing unit 101, respectively.
5 and the station 11 connected to the input / output ports 131 to 135
7 to 121. The input / output ports 131 to 135 are connected to the frame transmitters 107 to 111,
The frame receivers 112 to 116 are included.

In the above configuration, stations 117 to 118
The operation of the multi-port relay device will be described by taking as an example the case of transmitting a frame to. The frame transmitted from the station 117 is received by the frame receiver 112. The frame received by the frame receiver 112 is sent to the protocol processing unit 101. In the CSMA / CD method, the received frames may collide with each other. Therefore, the protocol processing unit 101 checks whether the received frames collide. When no frame collision is detected, the frame received by the protocol processing unit 101 is repeated, and the input / output port 132
~ 135 frame transmitters 108-111, respectively. Then, the frame transmitters 108 to 111 transmit the frames transmitted from the station 117 to the respective stations 118 to 121, and the stations other than the station 117 transmitting the frames receive the frames. This allows stations 117 to 118
The frame has been transmitted to.

[0006]

However, in the conventional multiport relay apparatus, since each station can receive the transmitted frame, there is a problem that important information is leaked to a station other than the transmission destination. there were.

Therefore, an object of the present invention is to provide a multi-port relay device that can transmit a frame only to a specific station and can protect important information.

[0008]

In order to solve the above-mentioned problems, the present invention is based on a filtering table in which station addresses of stations respectively connected to a plurality of input / output ports are registered, and the registered contents of the filtering table. A multi-port relay device comprising: a filtering determination unit that accepts only a frame in which a transmission source and a transmission destination are registered and transmits the frame only to the transmission destination.

The filtering table and filtering determination means may be provided corresponding to each of a plurality of input / output ports.

The multi-port relay device may also be configured to have a network connection port for connecting to another network to which a plurality of unknown stations are connected. It is desirable that the network connection port be provided with filtering determination means for filtering a frame transmitted to a station having a station address registered in the filtering table.

[0011]

In the multiport relay apparatus of the present invention, when a frame is transmitted from one station connected to a plurality of input / output ports to another station, whether the frame is filtered or forwarded by the filtering judgment means. It will be judged. That is, the destination address of the transmitted frame is compared with the station address registered in the filtering table. If they match, the frame is forwarded, and if they do not match, the frame is filtered. .

When the above frame is forwarded, the frame is repeated to stations other than the transmitting station and transmitted to each station. Also in this case, the filtering determination means determines whether to filter or forward the frame. That is, the destination address of the frame is compared with the station address registered in the filtering table. If they match, the frame is forwarded, and if they do not match, the frame is filtered. Therefore, the frame is transmitted only to the station designated as the destination address in the frame.

Further, the filtering table and the filtering determination means can be provided respectively corresponding to a plurality of input / output ports, whereby it is not necessary to check a plurality of points regarding registration of a station address and determination of filtering. Therefore, registration procedures and judgments become easy.

Furthermore, the multi-port relay device can also connect to another network by providing a network connection port for connecting to another network to which a plurality of unknown stations are connected. At this time, the network connection port is provided with filtering determination means to filter a frame whose destination address is the station address registered in the filtering table, and to pass a frame whose other destination address is the destination address. It is also possible to communicate with a station whose station address is unknown.

[0015]

First Embodiment A first embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a multiport relay device 100 of this embodiment. This multi-port relay device 100 includes, in addition to the one shown in FIG. 6 described in the section of the related art, a plurality of filtering determination units 102 to 106 provided corresponding to each input / output port, and frame filtering determination. A filtering table 122 in which the station address of the station connected to each input / output port that is referred to in this case is registered is provided. The filtering table 122 includes filtering decision units 102-1.
06 are respectively connected, and the station addresses 123 to 127 of the stations connected to the respective input / output ports are registered.

The operation of the multiport relay apparatus 100 will be described by taking the case of transmitting a frame from the station 117 to the station 118 as an example. First, the frame transmitted from the station 117 is received by the frame receiver 112. The received frame is transmitted to the filtering determination unit 102.

The filtering determination unit 102 performs processing according to the flowchart shown in FIG. S1
Then, the frame transmitted from the frame receiver 112 is received. Then, the source address (SA) of the received frame is compared with the station address 123 registered in the filtering table 122. As a result, when the source address and the registered station address match, the process proceeds to S2, and the frame is transferred to the protocol processing unit 10.
Sent to 1. On the other hand, if the source address and the registered station address do not match, the process proceeds to S3, the frame is filtered, and the protocol processing unit
A frame collision detection signal is output. Since such processing is performed, stations other than the station having the station address registered in the entry corresponding to each input / output port cannot perform frame transmission.

A frame normally transmitted to the protocol processing unit 101 without collision of frames is repeated by the protocol processing unit 101, and each input port other than the input / output port 131 to which the station transmitting the frame is connected. It is transmitted to the filtering determination units 103 to 106 corresponding to the output port.

In each of the filtering decision units 103 to 106, processing is performed according to the flow chart shown in FIG. In S4, the frame transmitted from the protocol processing unit 101 is received. Then, the destination address (DA) of the received frame and each station address 1 registered in the filtering table 122
24 to 127 are compared. As a result, when the destination address and the registered station address match, the process proceeds to S5, and the frame is transmitted to the frame transmitter. Now, since the frame transmission from the station 107 to the station 108 is considered, only the filtering determination unit 103 has the destination address and the registered station address 124 matched, and the frame is transmitted by the frame transmitter 10.
Sent to 8. On the other hand, another filtering determination unit 10
In 4 to 106, the destination address and the registered station address 125 to 127 do not match, so S
6, the frame is filtered, and a collision detection signal is output to the protocol processing unit 101. Since such processing is performed, even if the protocol processing unit 101 repeats a frame, frames other than the frame destined for the station that is the transmission destination are filtered.

Through the above processing, stations 117 to 118
The frame is transmitted to the other station, and the frame is not transmitted to other stations.

[0021]

Second Embodiment A second embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 4 shows the multiport relay device 100 of this embodiment. This multi-port relay device 100 is provided with the network connection port 200 for connecting the network 300 to which the unknown stations 301 to 304 are connected to the one of the first embodiment. The network connection port 200 includes a filtering ring determination unit 203 that determines whether to transmit a frame to the network 300, and a frame transmitter 2.
01 and a frame receiver 202.

The operation of the multiport relay apparatus 100 will be described by taking the case of transmitting a frame from the station 117 to the station 118 as an example. Note that the filtering determination units 102-1
Since the operation in 06 is the same as that in the first embodiment, its explanation is omitted here and the network connection port 20
The operation of the filtering determination unit 203 within 0 will be described.

The filtering determination unit 203 performs processing according to the flowchart shown in FIG. S7
Then, the repeated frame is received by the protocol processing unit 101. Then, the destination address of the frame is compared with all the station addresses registered in the filtering table 122. as a result,
If the destination address does not match any of the station addresses registered in the filtering table 122, the process proceeds to S8 and the frame is transmitted to the frame transmitter 201. On the other hand, if the destination address matches one of the station addresses registered in the filtering table 122, the process proceeds to S9, the frame is filtered, and a collision detection signal is output to the protocol processing unit. In this way, the frame is not transmitted to stations other than the transmission destination.

Further, the frame transmitted from the network 300 is received by the protocol processing unit 101 without passing through the filtering determination unit 203 and is repeated by each of the filtering determination units 102 to 106. Then, in each of the filtering determination units 102 to 106, the destination address of the frame is compared with the corresponding station address, and the frame is filtered or forwarded according to the processing described above.

[0025]

As described above, according to the multiport relay apparatus of the present invention, a frame is accepted only when the transmission source of the frame is registered, and the transmission destination is registered when the transmission destination of the frame is registered. Since the frame is transmitted only to the user, information leakage can be prevented.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing a first embodiment of the present invention.

FIG. 3 is a flowchart showing a first embodiment of the present invention.

FIG. 4 is a block diagram showing a second embodiment of the present invention.

FIG. 5 is a flowchart showing a second embodiment of the present invention.

FIG. 6 is a block diagram showing a conventional multi-port relay device.

[Explanation of symbols]

 100 multi-port relay device 101 protocol processing unit 102-106, 203 filtering determination unit 107-111, 201 frame transmitter 112-116, 202 frame receiver 117-121, 301-304 station 122 filtering table 123-127 station address 131 ~ 135 I / O port 200 Network connection port 300 Network

Claims (4)

[Claims] 1. A multi-port relay device comprising a plurality of input / output ports to which respective stations are connected, and transmitting a frame transmitted from the station to another station, wherein the multi-port relay device is connected to the plurality of input / output ports, respectively A filtering table in which the station address of the station is registered, and a filtering determination in which only the frame in which the transmission source and the transmission destination are registered based on the registration content of the filtering table are accepted and the frame is transmitted only to the transmission destination And a multi-port relay device. 2. The multiport relay apparatus according to claim 1, wherein the filtering table and the filtering determination unit are provided corresponding to each of the plurality of input / output ports. 3. The multiport relay device according to claim 1, wherein the multiport relay device includes a network connection port for connecting to another network to which a plurality of unknown stations are connected. 4. The network connection port comprises filtering determination means for filtering the frame transmitted to the station having the station address registered in the filtering table.
The described multi-port relay device.