JPH0824299B2 - Local area network system with multiple transmission lines - Google Patents

Description

The present invention relates to a local area network system with a plurality of transmission lines.

[Conventional technology]

Currently, as a local area network system,
There are bus type and loop type. Among them, the loop type local area network system has a duplicated transmission line because a failure of some devices may affect the entire network. Normally, either one of the transmission lines is used as a control means for the duplicated transmission line,
An alternative path method that uses the other transmission line when a failure occurs in that transmission line, and a node on both sides of the part that failed when a node failure or both transmission lines between nodes failed There is a loopback method in which the transmission line is looped over and operated.

On the other hand, also in the bus type local area network system, a failure of some devices has a high possibility of affecting the entire network, and therefore some systems have duplicated transmission paths. As the control means of this duplicated transmission line,
Normally, one of the transmission lines is used, and when a failure occurs in that transmission line, the alternative path method is used and the same message is almost sent to the two duplicated transmission lines. There is a simultaneous transmission method that operates by transmitting at the same time.

[Problems to be Solved by the Invention]

The conventional loop type local area network system of a plurality of transmission lines described above has a drawback that it is difficult to cope with a transmission line of triple or more in both the alternative path system and the loopback system. In the alternative path method, it is necessary to select which of the remaining paths will be used as an alternative path when one system has no failure, which complicates the selection method and causes a failure in the logical path. When setting later, delay of message transfer becomes a problem. Further, in the loopback method, there is a limitation that the number of transmission lines must be an even number because of the control method of returning the loopback.

On the other hand, the conventional bus-type local area network system with multiple transmission lines uses the alternative path method to determine whether the failure location of the logical path is the local area network connection mechanism of the node or the transmission path itself. However, as in the case of the loop type, the bus selection method becomes complicated when the number of triplicates is three or more. Also,
The simultaneous transmission method has a drawback that the CPU load on the transmitting side is doubled and there is a high risk that the input / output CPU load will greatly limit the processing capacity of the entire system.

[Means for solving the problem]

The local area network system with a plurality of transmission lines of the present invention stores a logical path for sending a message to another node on the sending side, stores the logical path for each party, and initializes the message when the logical path is set. Message identifier adding means for adding a transmission message identifier that changes according to a fixed rule each time a message is sent, to each message to be sent, and after adding the transmission message identifier to the message by the message identifier adding means, changing it according to a fixed rule Transmission message identifier updating means for updating the transmission message identifier to be added to the next message, and setting a logical path for transmitting a message to another node. It is stored for each partner and when the logical path is set. In the transmission path that initializes to a predetermined state and transmits And a time difference transmitting means for transmitting to a plurality of transmission lines in advance in the order of the transmission lines indicated by the transmission priority status by referring to the transmission priority status indicating the corresponding transmission order and transmitting message identifiers. , Performs a receiving operation for all transmission lines that can be received by the receiving side, stores each time a logical path is set when receiving a message from another node, and initializes when the logical path is set The sent message identifier is initialized to the same value as the sent message identifier, and every time a valid message is received, the expected message identifier that changes similarly to the sent message identifier according to a certain rule is compared with the sent message identifier added to the received message. Message judging means for judging whether the message is valid or not by matching , An expected message identifier updating means for changing the expected message identifier when a valid message is received according to a certain rule to an expected message identifier for receiving the next message, and a transmitted message identifier from the received valid message And a message identifier deleting means for deleting.

〔Example〕

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

FIG. 1 is a block diagram showing an embodiment of a local area network system having a plurality of transmission lines according to the present invention. In this embodiment, as shown in FIG. 1, a device 1 on the transmitting side and a device 2 on the receiving side are connected to each other by three transmission lines 31, 32, 33, and nodes 41, 42, 43 on the transmitting side and a receiving side. The nodes 51, 52, 53 are connected to each other.

First, a method of setting a message transmission priority status and a method of setting a transmission time interval between transmissions for determining a transmission order corresponding to a transmission path to be transmitted prior to communication will be described.

In this embodiment, since transmission is performed with a time lag on each transmission line 31, 32, 33, and if there is a reception response from the transmission line that has been preferentially transmitted, another transmission is stopped, the transfer amount of each message Examine and set the message transmission priority status for each transmission destination so that the message transfer amount is distributed to multiple transmission lines 31, 32, 33 and store the transmission priority status
Store in 19. Further, the transmission time interval is set to a time larger than the time required for transmitting / receiving a general message and stored in the transmission time interval storage 20.

Next, a method of initializing the transmission message identifier and the expected message identifier in setting the logical path and a method of managing the transmission path will be described.

When setting the logical path from the device 1 to the device 2 in FIG. 1, the device 1 establishes a data link with the device 2 for each of the transmission lines 31, 32 and 33.

Then, the device 1 initializes the transmission message identifier for the device 2 and stores it in the transmission message identifier storage 15, and also gives an initialization instruction of the expected message identifier through each of the transmission paths 31, 32, 33 in which the data link is established. Since it is transmitted to the device 2, when the device 2 first receives the initialization instruction of the expected message identifier, the device 2 initializes the expected message identifier for the device 1 and stores it in the expected message identifier storage 26, and when the initialization instruction is received, the transmission is performed. Send a response on each of the paths 31, 32, 33 only. Therefore, the device 1 sets each of the available status storages 16, 17, 18 of only the transmission paths 31, 32, 33 that received the response to the "enabled" state.
Therefore, the logical paths between the device 1 and the device 2 are in a connected state, and transmission / reception is possible.

Next, the operation of transferring a message from the device 1 to the device 2 will be described.

The transmission message identifier and the message identifier in this embodiment are n-bit binary numbers, and the initial value is 1, and 1 is added each time a message is transferred.

In the device 1, the message processing unit 11 generates a message to be transferred, and the message identifier adding means 12 extracts the transmission message identifier of the device 2 from the transmission message identifier storage 15 and adds it to the message. Then, the transmission message identifier updating means 13 adds 1 to the transmission message identifier of the device 2 and stores it in the transmission message identifier storage 15.

Next, referring to the transmission priority status memory 19 in the time difference communication means 14 for a plurality of transmission paths, the available status memory 17 that responds to the transmission path 32 with the highest priority is checked, and if the status is "possible", the transmission is performed. The message to which the message identifier is added is transmitted through the transmission path 32. If the usable status is "impossible", the same processing is performed on the transmission path 31 having the next highest priority.

Next, when the data is transmitted to the device 2 via the transmission path 32, the response is monitored at the transmission time interval of the transmission time interval storage 20. If there is a reception response from the device 2 during this monitoring time, the transmission operation on the device 1 side is completed. If there is no reception response from the device 2 during this monitoring time, the same processing is performed on the transmission path 31 having the next highest priority.

When the message sent from the device 1 is sent via the transmission line 32, the device 2 receives the message from the transmission line 32 by the received message judging means 21, and the device 2 adds the message to the message. Since the transmitted message identifier and the expected message identifier of the device 1 retrieved from the expected message identifier storage 26 match, it is determined that the message is a valid message, and the expected message identifier updating means 22 sets 1 to the expected message identifier of the device 1. in addition,
Stored in the expected message identifier storage 26. Then, the message identifier deleting unit 23 deletes the transmitted message identifier from the received message, and then the message processing unit
At 24, the message is processed, and the response message transmitting means 25 transfers the response to the device 1 through the transmission path 32. It should be noted that the received device name and the transmitted message identifier are added to this response in the same manner as the transmitted message so that the device 1 side can judge which message the response is to.

If this response is not notified to the device 1 within the transmission time interval, the same message is subsequently received from the transmission lines 31 and 33, but since the expected message identifier has already been incremented by 1, the received message is Since the transmission message identifier and the expected message identifier added to the ID do not match and are ignored, they will not be duplicated.

〔The invention's effect〕

As described above, the local area network system with a plurality of transmission lines of the present invention transfers a message to a plurality of transmission lines with a slight time difference, so that even if some of the transmission lines fail, The message can be transferred to the destination node without delay. At the same time, even if a failure occurs in the transmission line, the transmission line is not used, so that the control is simple and the manufacturing man-hours of the local area network system itself can be reduced.

In addition, the local area network system having a plurality of transmission lines according to the present invention has one message for one message at the time of steady operation.
Since it can be operated by sending and receiving operations once, the CPU load on the sending side and receiving side does not increase, and it is possible to set the message transmission priority status to be load-balanced for multiple transmission lines. This has the effect of being able to respond flexibly to an increase in the message volume.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a local area network system having a plurality of transmission lines according to the present invention. 1, 2 ... Device, 11 ... Message processing unit, 12 ... Message identifier adding means, 13 ... Transmission message identifier updating means, 14 ... Time difference communication means for multiple transmission lines, 15 ... Transmission message identifier storage , 16,17,18 …… Available status memory, 19 …… Sending priority status memory, 20 …… Sending time interval memory, 21 …… Reception message judging means, 22 ……
Expected message identifier updating means, 23 ... Message identifier deleting means, 24 ... Message processing unit, 25 ... Response message transmitting means, 26 ... Expected message identifier storage, 3
1,32,33 …… Transmission path, 41,42,43,51,52,53 …… Node.

Claims (1)

[Claims] 1. A transmission side sets a logical path for sending a message to another node, stores the logical path for each party, initializes when the logical path is set, and sets a fixed rule every time a message is sent. Message identifier adding means for adding a transmission message identifier that changes according to the above-mentioned message to each message to be transmitted, and the transmission message identifier should be added to the message by the message identifier adding means and then changed according to a certain rule to be added to the next message. Sending message identifier updating means for updating to a sending message identifier and a logical path for sending a message to another node are stored for each party and initialized to a predetermined state when the logical path is set. Refer to the transmission priority status that indicates the transmission order corresponding to the transmission path to be performed and transmitted. A message with a transmission message identifier added to it is transmitted to each of the plurality of transmission paths at a predetermined time interval in the order of the transmission paths indicated by the transmission priority status. This is the same as the transmission message identifier initialized when the logical path is set, and it is stored every time a logical path is set when receiving a message from another node by performing a receiving operation on all transmission paths. The value is initialized and the expected message identifier, which changes similarly to the sent message identifier according to a certain rule each time a valid message is received, is compared with the sent message identifier added to the received message, and whether or not they match Received message judging means for judging whether or not the message is valid and a valid message is received. An expected message identifier updating means for changing the expected message identifier of the above message to an expected message identifier for receiving the next message, and a message identifier deleting means for deleting the transmitted message identifier from the received valid message. A local area network system having a plurality of transmission lines.