Bridge equipment

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a bridge device, and more particularly to a MAC (Media Access Control) bridge device that relays the second layer of an OSI (Open Systems Interconnection) reference model, which is an international standard for data communication.

【0002】

[Conventional technology]

Conventionally, the MAC bridge device has registered the source address and the receiving port name of the frame passing through the own device inside the device. Then, the passage / blocking of the received frame is determined from the registered information, and if the information of the same address already exists at the time of information registration, only the information is updated and no special processing is performed. Therefore, even if the received frame loops through the network and is received by the MAC bridging device from a different port again, it cannot be detected.

【0003】

This conventional MAC bridging device will be described with reference to FIG.

【0004】

FIG. 3 is a block diagram showing an internal configuration of a conventional MAC bridge device. In the figure, the conventional bridge device 1 is provided corresponding to each of the transmission lines 13a and 13b, and receives the frames received by the receiving drivers 2a and 2b and the frames received by the receiving drivers 2a and 2b, respectively. It is configured to include receive buffers 3a and 3b to be stored and a bridge processing unit 4 that controls relay processing of the bridge device.

【0005】

Further, the conventional bridge device 1 is provided with an address storage unit 5 that holds the source address and the receiving port name of the receiving frame, and a frame that is provided corresponding to each of the transmission lines 13a and 13b and should be transmitted to the corresponding transmission lines. The transmission buffers 10a and 10b for storing the stored frames and the transmission drivers 11a and 11b for transmitting the stored frames to the transmission lines 13a and 13b, respectively, are included.

【0006】

The bridge device 1 having such a configuration is connected to the transmission line 13a via the reception driver 2a and the transmission driver 11a, and is connected to the transmission line 13b via the reception driver 2b and the transmission driver 11b. That is, the frame is transferred between networks.

【0007】

[Problems to be Solved by the Invention]

In the conventional MAC bridge device 1 described above, even when loop frames are alternately received from transmission lines 13a and 13b, the bridge processing unit 17 updates the source address and reception port name information in the address storage unit 18. I was relaying a loop frame. Therefore, the loop frame exists on the network endlessly and has a drawback of occupying the communication band on the network.

【0008】

Although MAC bridges are described in JP-A-5-75615 and JP-A-5-75616, loop frames cannot be detected by such bridges.

【0009】

The present invention has been made to solve the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a bridging device capable of detecting a loop frame.

【0010】

[Means for solving problems]

The bridge device according to the present invention is a bridge device that performs frame transfer processing between the first and second networks, and is from the source address of the frame received from the first network and previously from the second network. It is characterized by including a comparison means for comparing the source address of the received frame and a frame discarding means for discarding the frame when it is shown that the comparison result is the same.

【0011】

BEST MODE FOR CARRYING OUT THE INVENTION

The action of the present invention is as follows.

【0012】

Compare the source address of a frame received from one network with the source address of a frame previously received from another network. When this comparison result shows that they are the same, it can be determined that the frame is a loop frame, and it is discarded.

【0013】

Next, examples of the present invention will be described with reference to the drawings.

【0014】

FIG. 1 is a block diagram showing a configuration of an embodiment of a bridging apparatus according to the present invention, and the same parts as those in FIG. 3 are indicated by the same reference numerals.

【0015】

In the figure, the bridge device according to the embodiment of the present invention is provided by the receiving drivers 2a and 2b corresponding to the transmission lines 13a and 13b and receiving frames from the corresponding transmission lines, respectively, and the receiving drivers 2a and 2b, respectively. It is configured to include receive buffers 3a and 3b for storing received frames and a bridge processing unit 4 for controlling relay processing of the bridge device.

【0016】

Further, the bridge device 1 inputs the address storage unit 5 that holds the source address, the reception port name, and the registration time of the reception frame, and the loop detection time difference and the upper limit number of loops that are parameters used for the loop detection process. Console 12, the parameter holding unit 6 that holds the loop detection time difference and the maximum number of loops input from the console 12 as parameters, and the registration time and the current registration time before the information in the address storage unit 5 is updated. It is configured to include a loop count storage unit 7 that holds the update count of the address count when the time difference from the time is within the loop detection time difference held in the parameter holding unit 6. The address storage unit 5 can store a plurality of receiving port names and registration times for the same source address.

【0017】

Furthermore, the bridge device 1 includes a loop detection unit 8 that instructs the frame blocking processing unit 9 to perform frame blocking processing when the number of updates of the loop number storage unit 7 exceeds the loop upper limit number in the parameter holding unit 6. The frame blocking processing unit 9 that actually performs the frame blocking processing, the transmission buffers 10a and 10b that are provided corresponding to the transmission lines 13a and 13b and store the frames to be transmitted to the corresponding transmission lines, and the stored. It is configured to include transmission drivers 11a and 11b that transmit frames to transmission lines 13a and 13b, respectively.

【0018】

In such a configuration, the bridge device 1 receives a frame from the transmission line 13a by the reception driver 2a and stores it in the reception buffer 3a. Further, the bridge device 1 receives a frame from the transmission line 13b by the reception driver 2b and stores it in the reception buffer 3b.

【0019】

For the frame stored in the reception buffer 3a, the source address, the reception port name, and the registration time are stored in the address storage unit 5. Further, the source address, the receiving port name, and the registration time of the frame stored in the receiving buffer 3b are also stored in the address storage unit 5. If the time stored in the reception buffer is ignored, this registration time can be regarded as the reception time.

【0020】

Here, if the same address is already stored in the address storage unit 5 with a different port name, and the time difference between the registration time and the current time is within the loop detection time difference in the parameter holding unit 6. The information in the address storage unit 5 is updated, and the address and the update count are stored in the loop count storage unit 7. The loop detection unit 8 compares the update count of the loop count storage unit 7 with the loop upper limit count of the parameter holding unit 6 each time the stored contents of the loop count storage unit 7 are updated.

【0021】

Then, as a result of this comparison, when the update count of the loop count storage unit 7 exceeds the loop upper limit number of the parameter holding unit 6, the address exceeding the loop upper limit count is passed to the frame blocking processing unit 9. The frame blocking processing unit 9 that has received this address information discards the frame whose source address is that address and blocks it only once. At the same time, the loop detection unit 8 deletes the entry of the loop count storage unit 7 and the entry of the address storage unit 5 for the address.

【0022】

Here, it is appropriate that the loop detection time difference, which is a parameter used for the loop detection process, is 1 second and the upper limit of the loop is about 5 times, but these values may be freely changed according to the system configuration. That is, since the values of the loop detection time difference and the loop upper limit number of times can be freely input from the console 12, the optimum loop detection process can be performed according to the system configuration.

【0023】

Further, the operation of the bridge device of this embodiment will be described with reference to FIG. FIG. 2 is a flowchart showing the operation of the bridge device of FIG.

【0024】

Bridge device 1 constantly monitors for the reception of frames (step 201). Then, when a frame is received, the bridge processing unit 4 determines whether or not the same address is already stored in the address storage unit 5 with a different port name (step 201 202).

【0025】

As a result, if it is determined that the frame is not stored, the source address, receiving port name, and registration time of the frame are stored in the address storage unit 5, and the process ends (step 202 208 209). .. On the other hand, if it is determined that the memory has already been stored and the time difference between the registration time and the current time is within the loop detection time in the parameter holding unit 6, the stored contents of the address storage unit 5 are updated (step 202 . 203) Further, the update count is stored in the loop count storage unit 7.

【0026】

Next, the update count of the loop count storage unit 7 and the upper limit loop count in the parameter holding unit 6 are compared (step 205). Then, if the number of updates does not exceed the upper limit of the loop, the process ends as it is (step 205 209). On the other hand, if the number of updates exceeds the upper limit of the loop, the frame is discarded and the frame is blocked (step 206). After that, the corresponding entries of the address storage unit 5 and the loop count storage unit 7 are deleted (step 207), and the process ends (step 207 209).

【0027】

In short, in the bridge device of this example, when the address and port name registered inside the device are updated, the time difference between the previous registration time and the update time and the address update after the device is started or the previous loop is detected. Two values, the number of times, are retained inside the device, and when the update of the registration update time difference within the set threshold value occurs more than the set number of updates, the frame is discarded and blocked. There is. This allows the loop frame to be removed from the network. Then, by blocking the frame looping the network with the bridge device, the load on the network increased by the loop frame can be suppressed.

【0028】

In this embodiment, it is determined in step 202 whether the same address is stored under a different port name, and the number of updates is determined in step 205. This is because the source device moves to the other network side due to the change in the system configuration simply by comparing the source address of the frame received from one network with the source address of the frame received from another network before. This is because there are cases. That is, this is to prevent the frame of the device that has moved the network from being discarded due to the change in the system configuration. Therefore, if there is no change in the system configuration, it is not necessary to determine the number of updates in step 205, and the loop frame is detected only by determining whether the same address in step 202 is stored under a different port name. Can be done.

【0029】

In connection with the description of the claims, the present invention may further take the following aspects.

【0030】

(4) The bridge device according to any one of claims 1 to 3, wherein the predetermined time is freely set from the outside.

【0031】

(5) The bridge device according to any one of claims 1 to 4, wherein the predetermined number of times is freely set from the outside.

【0032】

[Effect of the invention]

As described above, the present invention loops by discarding a frame when the source address of a frame received from one network and the source address of a frame previously received from another network are the same. By blocking the frame with the bridge device, there is an effect that the network load increased by the loop frame can be suppressed.

[Simple explanation of drawings]

[Figure 1]

It is a block diagram which shows the structure of the bridge apparatus according to the Example of this invention.

[Figure 2]

It is a flowchart which shows the operation of the bridge device of FIG.

[Fig. 3]

It is a block diagram which shows the structure of the conventional bridge apparatus.

[Explanation of symbols]

1 Bridge device 2a, 2b receiving driver 3a, 3b receive buffer 4 Bridge processing unit 5 Address storage 6 Parameter holder 7 Loop count storage 8 Loop detector 9 Frame cutoff processing unit 10a, 10b transmit buffer 11a, 11b transmission driver 13a, 13b transmission line 12 console