JPH0773263B2 - Local area network equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used for a local area network device for in-house data transmission. In particular, it relates to a local area network device having a plurality of transmission paths.

〔Overview〕

The present invention is, in a local area network device, a transmission data identifier of a destination node that is updated according to a predetermined rule for each data transmission, and expected data of the destination node that is updated according to the above-described predetermined rule each time valid reception data is received. The identifiers are stored, both identifiers are initialized when the logical path is set, the transmission data identifier is added to the transmission data when transmitting the data, and the transmission data identifier and the expected data are added on the receiving side. By determining that the received data is valid when the identifier matches, the data can be transferred to the target node without delay even if a failure occurs in any of the transmission paths, and the device control method is simple and hard. It is a product that makes it easy to wear.

[Conventional technology]

2. Description of the Related Art Conventionally, local area network devices are mainly of a bus type and a loop type. Among these, in some loop-type local area network devices, there is a possibility that a failure of some terminals has a great influence on the entire network, so that the transmission path is duplicated. As a control means for this duplicated transmission line, either one of the transmission lines is usually used, and if a failure occurs in that transmission line, the other transmission line method is used and a node There is a loopback method in which when both a failure and two transmission paths between nodes fail, the nodes on both sides of the failed portion loop back the transmission path to operate.

[Problems to be solved by the invention]

However, such a conventional local area network device has a drawback that it is difficult to cope with a transmission path of triple or more in the case of the alternative path system or the loopback system in the loop type local area network device. That is, in the alternative path method, the selection method becomes complicated because there is room to select which of the remaining alternative paths to use when one system fails.

On the other hand, the loopback method has a drawback in that the number of transmission paths must be an even number because of the control method of returning to the loopback method.

In a bus type local area network, for example, if an alternative path method in the loop type is applied, the alternative path is selected depending on whether the faulty part of the logical path is the local area network connecting means of the partner node or the transmission path itself. Although it is carried out, it is difficult to judge whether reconnection should be attempted, and there is a drawback that the path selection method becomes complicated when the number of triplings is three or more as in the loop type.

In addition, both methods have a drawback that the flow of data on the local area network is stagnant until the failure is detected because the recovery processing is performed after the failure is detected.

The present invention solves the above-mentioned drawbacks. Even if a failure occurs in any of the transmission paths, data can be transferred to the target node without delay, and the device control method is simple and the hardware is simple. It is an object of the present invention to provide a local area network device that can be used.

[Means for solving problems]

The present invention comprises a local area network having a plurality of transmission paths and a plurality of nodes respectively connected to the respective transmission paths, wherein each of the nodes controls transmission of transmission / reception data and transmits the data to other nodes. In a local area network device including a transmitting / receiving unit that sets a logical path when transmitting, the transmitting / receiving unit of each node includes a unit that transmits the same data to a plurality of transmission paths in which the logical paths are set, The node has a first area in which the transmission data identifier of the destination node, which is updated according to a predetermined rule for each data transmission, is stored, and a predetermined rule corresponding to the above transmission data identifier each time valid data is received. A second area in which an expected data identifier of the partner node to be updated is stored. And a means for initializing the corresponding contents of the second area, respectively, each node, after adding the same transmission data identifier to the same transmission data to be transmitted to a plurality of transmission lines A means for updating the transmission data identifier according to a predetermined rule, and a means for comparing the transmission data identifier added to the reception data with the expected data identifier of the second area to determine whether or not the reception data is valid. And a means for updating the expected data identifier of the second area according to a predetermined rule and deleting the transmission data identifier added from the received data when the determination result of the determination means is valid. To do.

[Action]

Each node has a first area in which the transmission data identifier of the destination node that is updated according to a predetermined rule for each data transmission is stored, and a destination node that is updated according to the above-mentioned rule each time valid data is received. A second area for storing the expected data identifier of is provided. The transmitting / receiving means initializes the corresponding contents of the first area and the second area when setting the logical path. The transmission side node updates the transmission data identifier of the first area after adding the transmission data identifier of the first area corresponding to the destination node to the transmission data. At this time, the same transmission data identifier is added to the same transmission data sent to a plurality of transmission paths. The transmission / reception means of the transmission side node compares the transmission data identifier added to the reception data on the transmission line with the expected data identifier of the partner node in the second area to determine whether this reception data is valid or not. If all the received data on the transmission path is not valid, the logical path is disconnected. The means for deleting deletes the transmission data identifier added from the received data by updating the expected data identifier of the second area when the judgment result of the judgment means is valid.
Since the transmission data identifier and the expected data identifier are updated according to the corresponding rules, it can be determined whether the reception data is valid. By the above operation, even if a failure occurs in any of the transmission paths, data can be transferred to the target node without delay, and the control method of the device is simple and the hardware can be simplified.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a local area network device according to an embodiment of the present invention. In the figure, a local area network device includes a local area network 50 having a plurality of transmission lines 54 ₁ , 54 ₂ , 54 ₃ and connection means 51 ₁ , 51 ₂ , 52 ₁ , 52 ₂ , for each transmission line 54. 53 ₁ and 53 ₂ are connected to each other through a plurality of nodes 10 ₁ and 10 _2, and each node 1
0 ₁ and 10 ₂ are data processing units 11 ₁ and 11 _{2 for} processing transmission / reception data, and transmission / reception means 14 _{1 for} controlling transmission of transmission / reception data and setting a logical path when transmitting data to another node. , 14 ₂ and flag areas 30 ₁ , 30 ₂ for storing flags 31 ₁ , 31 ₂ , 32 ₁ , 32 ₂ , 33 ₁ , 33 ₂ indicating whether or not each transmission path 54 can be used. .

Here, the feature of the present invention is that each node 10 transmits as a first area in which transmission data identifiers 21 ₁ and 21 _{2 of the} destination node, which are updated by a predetermined rule for each data transmission, are stored. The data identifier areas 20 ₁ and 20 ₂ and the expected data identifiers 41 ₁ and 41 _{2 of the} destination node which are updated according to the above-mentioned predetermined rule every time valid data is received are stored as the second area. Including regions 40 ₁ and 40 ₂ ,
The transmitting / receiving means 14 includes means for initializing the corresponding contents of the transmission data identifier area 20 and the expected data identifier area 40 at the time of setting the logical path, and each node 10 corresponds to the transmission data in the transmission data identifier area 20. Data identifier adding means as means for updating the corresponding contents of the transmission data identifier area 20 after adding the contents and giving it to the transmitting / receiving means 14.
12 ₁ and 12 ₂ and transmission data identifier updating means 13 ₁ and 13 ₂ , and the transmission / reception means 14 stores the transmission data identifier added to the reception data on the transmission path 54 and the corresponding contents of the expected data identifier area 40. The node includes means for comparing and judging whether the received data is valid, and each node has an expected data identifier area 40 when the judgment result of the judging means is valid.
Of expected data identifier adding means 15 ₁ , 15 ₂ and data identifier updating means 16 ₁ , 1 as means for updating the corresponding contents of the received data and deleting the added transmission data identifier from the received data.
6 ₂ is included.

The operation of the local area network device having such a configuration will be described.

First, the initialization of the data identifier in the setting of the logical path,
A method of managing the transmission path will be specifically described.

In the figure, when setting a logical path from the node 10 ₁ to the node 10 ₂ , the node 10 ₁ establishes a data link with the node 10 _{2 in} each of the transmission lines 54 ₁ , 54 ₂ and 54 ₃ .
The node 10 _{1 first} transmits to the node 10 ₂ an instruction to initialize the data identifier through the transmission path with the data link, and waits for a response. When the node 10 ₂ receives the initialization instruction of the data identifier, the node 10 ₂ initializes the transmission data identifier for the node 10 ₁ and the expected data identifier, and uses the transmission line that has received the initialization instruction for the data identifier of the node 10 ₁ The enable / disable flag is set to "enabled" and a response is transmitted to the corresponding transmission path. When the node 10 ₁ receives the response, the node 10 ₁ initializes the transmission data identifier and the expected data identifier for the node 10 ₂ and sets a flag indicating that the corresponding transmission path of the node 10 ₂ is unavailable is “enabled”. To Where node 10
Logical path between ₁ and node 10 ₂ is in a state of being connected, it is ready to exchange data with each other. For the other transmission paths, when the two conditions are satisfied, that is, the transmission path with the first data link can be used and that the data link of each transmission path can be taken, the transmission path use start instruction is issued on the node 10 ₁ side. Send from The node 10 ₂ sets the flag of the corresponding transmission line of the paired node 10 ₁ to “enabled” for the transmission line that has received the transmission line use start instruction, and returns the response to the node 10 ₂ . Upon receiving the response, the node 10 ₁ sets the flag of the corresponding transmission line of the node 10 ₂ to “enabled”. Node 10
All transmission line ₁ and the node 10 ₂ can be used.

Next, a flow of data transfer from the node 10 ₁ to the node 10 ₂ will be described.

The transmission data identifier and the expected data identifier are n-bit binary numbers (n is assumed to be a sufficiently large value),
The initial value is "1", and "1" is added every time data is transferred.

The node 10 ₁ adds the transmission data identifier of the node 10 _{2 to} the data to be transferred. Then "1" is added to the transmission data identifier pairs node 10 _2. Subsequently, the flag corresponding to the transmission path 54 ₁ of the node 10 ₂ is checked, and if the flag is “possible”, the data with the transmission data identifier is transmitted to the transmission path 54 ₁ . To the transmission path 54 ₂ without having its completion,
Data is transmitted to the transmission path 54 ₃ after the transmission path 54 ₂ in the same manner. Here, it is assumed that the data sent from the node 10 ₁ arrives at the node 10 ₂ in the order of the transmission path 54 ₁ , the transmission path 54 ₂ , and the transmission path 54 ₃ . When the node 10 ₂ receives the data from the transmission path 54 ₁ , the transmission data identifier added to the data matches the expected data identifier of the opposite node 10 ₂ , so it is determined as valid data, and the expected data of the opposite node 10 ₁ is determined. "1" for the identifier
Add. Next, after deleting the data identifier from the received data, the data is processed. Then the transmission line
Even if the same data is received from 54 ₂ and 54 ₃ , the expected data identifier has already been added with "1", so the data identifier added to the received data and the expected data identifier do not match and are ignored. Therefore, it will not be processed redundantly.

Further, the operation when a failure occurs will be described.

It is assumed that the transmission path 54 ₁ is disconnected after the above-mentioned data transfer. In the node 10 ₁ , the transmission data identifier is added to the transmission data as in the previous data transmission, “1” is added to the transmission data identifier of the node 10 _{2 and} the transmission path 5
4 and transmits the _first data to the three transmission lines all because it does not detect the failure. At this time, since the transmission line 54 ₁ is disconnected, a procedural retry is performed on the transmission line 54 ₁ . However, since the data sent through the transmission path 54 ₂ and the transmission path 54 ₃ are normally transferred, either data is processed normally. If retry the transmission line 54 ₁ is unsuccessful, a failure of the transmission line 54 ₁ node 10 ₁ is detected, the node
10 ₁ sets the flag corresponding to the transmission path 54 ₁ of the node 10 ₂ to “disable”. After that, since this flag is set to “impossible”, the node 10 ₁ will not use the transmission path 54 ₁ in the data transfer to the node 10 ₂ .

Further, when the node 10 ₂ itself fails, it is assumed that the logical path between the node 10 _{1 and} the node 10 ₂ is cut off because all the transmission paths fail.

〔The invention's effect〕

As described above, since the same data is transferred to a plurality of transmission paths almost at the same time, even if a failure occurs in any of the transmission paths, it is possible to transfer data to a target node without delay. is there. Further, even if a failure occurs in the transmission line, the transmission line is simply not used, so that the control method is simplified, and the hardware of the local area network device can be simplified, and the number of manufacturing steps can be reduced. .

[Brief description of drawings]

FIG. 1 is a block diagram of a local area network device according to an embodiment of the present invention. 10 ₁ , 10 ₂ …… Node, 11 ₁ , 11 ₂ …… Data processing unit, 1
2 ₁ , 12 ₂ ...... Data identifier adding means, 13 ₁ 13 ₂ ...... Transmission data identifier updating means, 14 ₁ , 14 ₂ ...... Transmitting / receiving means, 15 ₁ , 1
5 ₂ …… Expected data identifier updating means, 16 ₁ , 16 ₂ …… Data identifier deleting means, 20 ₁ , 20 ₂ …… Transmission data identifier area,
20 ₁ , 20 ₂ …… Transmission data identifier (hatched areas are nodes 10 ₂ , 1
(Corresponding to 0 ₁ ), 31 ₁ , 31 ₂ ...... Flag indicating that the transmission path 54 ₁ cannot be used (hatched portions correspond to nodes 10 ₂ and 10 ₁ ), 3
2 _1, 32 ₂ ...... indicating channel ₅₄₂ of the available non flag (hatched portion corresponds to the node 10 _2, 10 _1), 33 _1, 33 ₂ ...... transmission path 54 ₃ usable not Indicates the flag (hatched area is node 1
0 ₂ , 10 ₁ ), 40 ₁ , 40 ₂ ... Expected data identifier area, 41 ₁ , 41 ₂ ... Expected data identifier (hatched area is node 10
_2, 10 corresponds to _1), 50 ...... local area network,
51 ₁ , 51 ₂ , 52 ₁ , 52 ₁ , 52 ₂ , 53 ₁ , 53 ₂ ... Local area network connection means, 54 ₁ , 54 ₂ , 54 ₃ ... Transmission line.

Claims (1)

[Claims] 1. A local area network having a plurality of transmission paths, and a plurality of nodes respectively connected to the respective transmission paths, wherein each of the nodes controls transmission / reception of transmission / reception data and transmits data to another node. In a local area network device including a transmission / reception means for setting a logical path when transmitting, the transmission / reception means of each node includes means for transmitting the same data to a plurality of transmission paths in which the logical path is set, Each node has a first area in which the transmission data identifier of the destination node, which is updated according to a predetermined rule for each data transmission, is stored, and a predetermined rule corresponding to the transmission data identifier each time valid data is received. And a second area in which the expected data identifier of the partner node updated by the above is stored. Of the first area and the second area, and each of the above-mentioned nodes includes means for initializing the corresponding contents, and after adding the same transmission data identifier to the same transmission data to be transmitted to a plurality of transmission lines, A means for updating the transmission data identifier of the area according to a predetermined rule and the transmission data identifier added to the reception data and the expected data identifier of the second area are compared to determine whether the reception data is valid or not. And a means for updating the expected data identifier of the second area according to a predetermined rule and deleting the transmission data identifier added from the received data when the determination result of the determination means is valid. Characterized local area network device.