JPS63242043A - Node station for local area network system - Google Patents

Abstract

PURPOSE:To instantly cope with the abnormality of an operational node by operating one of nodes as an operation node and the others as supervisory nodes and allowing the supervisory node to play a roll of the operation node when the operation of the operation node is abnormal. CONSTITUTION:A supervisory node 3a is in standby till a text is received from an active transmission line 1a and a received text is buffered in a RAM 31 and the text is sent to the operation node 3b to discriminate whether or not the text is returned after a prescribed time via a standby transmission line 1b. When no replay comes and the result of collating the returned text is noncoincident, the supervisory node 3a discriminates the operation of the operating node 3b is abnormal, after the operation stop instruction is sent to the operation node 3b to start the operation mode by itself. Thus, when the operation node is abnormal, the supervisory node applies the operating mode in place thereof, thereby coping with the abnormality instantly.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a node stage system of a local area network system having a circular (loop-shaped or ring-shaped) transmission line, and particularly relates to improving its reliability.

(b) Summary of the Invention A node station of a local area network system according to the present invention includes two node units each capable of operating in an operational mode independently, and one node unit (operating node unit) is a node station of a local area network system according to the present invention. It operates in the operational mode as a station, and the other node section (monitoring node section) monitors the operating node section.

As a result, when the monitoring node unit discovers an abnormality in the operational node unit, it can notify the control device of the abnormality and request response processing, or perform operation mode operation on behalf of the operational node unit. . As a result, the inability to transmit data due to the failure of the operating node can be minimized, and the reliability of the local area network system as a whole is improved.

(C1 Conventional technology) Currently, local area network systems are being put into practical use as systems for online sharing of data held by multiple data devices installed in factories, buildings, etc. A schematic diagram of a local area network system having a network is shown in FIG.

A plurality of node stations 3 are connected to a main system 1 having a ring-shaped transmission path, and each node station 3 has a subsystem 2, a center device 4, . A data processing device such as a data terminal equipment (DTE) 5 is connected. The subsystem 2 connected to the main system 1 via the node stations 3m-3s is also a local area network having a ring-shaped transmission path, and this subsystem A2 also has a plurality of data terminals connected via the node station 3. A device (DTE) 5 is connected.

Data (telegram) transmitted from any data processing device is relayed by each node station and then transmitted to the node station connected to the target data processing device.

In the ring-shaped transmission line as described above, the direction of data transmission is generally determined, and if a failure occurs in a part of the transmission line, subsequent data transmission to the node station becomes impossible.

To solve this problem, many of the systems currently in practical use have dual transmission lines, so that when one fails, the other is used to transmit data, and both fail at the same location. When a problem occurs (such as when a cable is cut), a loopback method is used in which data is transmitted by looping back on both sides of the failure point to avoid a system failure due to a transmission line failure.

(d) Problems to be solved by the invention By duplicating the transmission line as described above, it is possible to eliminate system downtime due to transmission line failure, and even if one of the node stations goes down, both of the node stations next to it can System downtime can be resolved by loop bank transmission. However, the node station cannot determine its own abnormality, and the abnormality is detected by the data processing device only when the node station goes down and data transmission and reception become impossible. Therefore, in a data processing device,
There was a problem in that data transmission and reception became impossible without taking appropriate measures.

In particular, if the node station that connects the main system and subsystem goes down, such as 3m and 3S in Figure 3, the entire subsystem will go down, and the functionality of the system will be impaired. Became.

For example, multiple local area network systems that combine main systems and subsystems are introduced in nuclear power plants and ship navigation equipment, but if a node station installed on site goes down, maintenance is not easy, and subsystems are difficult to maintain. There were concerns about reliability, as a system failure could be fatal to the entire system.

This invention was made in view of these conventional problems, and provides a node for a local area network system that has multiple node sections and monitors one of the nodes, making it extremely easy to discover abnormalities. The purpose is to provide a station.

(Means for Solving Problem e1) This invention provides an operational node unit that operates in a normal operation mode in a node station that connects two transmission lines of a circular local area network system having a plurality of transmission lines. A monitoring node unit that monitors the operation of the operational node unit is provided consecutively on the two transmission paths,
The operation node section is provided with a reply means for replying a message received from the monitoring node section via one transmission path to the monitoring node section via the other transmission path, and the monitoring node section is provided with a message received from the monitoring node section via one transmission path. The present invention is characterized in that it is provided with a temporary storage means for temporarily storing a message received from the network, and a comparison means for comparing the message stored in the temporary storage means and the message returned from the operation node section.

([1 Operation] The local area network system of the present invention operates as follows.

The message relayed by the monitoring node unit via one transmission path,
The operational node unit sends a reply through the other transmission path. The monitoring node unit checks whether the returned message matches the original message (in this case, it is not necessary to completely match, and it is sufficient that the number of errors is below a certain level). If there is a mismatch as a result of the comparison, it is possible to determine that the operation of the operating node section is abnormal. After making this determination, the monitoring node unit may take actions such as, for example, notifying the data processing device of the abnormality and requesting a corresponding action, or stopping the operation of the operating node unit and starting the operation mode operation itself. It can be carried out. As a result, the reliability of the entire system can be improved. The overall configuration is similar to the local area network system shown in FIG. 4, and the node station 3 has the configuration shown in the figure.

FIG. 1 shows node stations 3m and 3s.

In this figure, 3a and 3b correspond to 3m, and 3c and 3d correspond to 38. All the node parts 3a to 3d are configured in the same way. Here, the configuration of the monitoring node section 3a of the node station 3m will be explained.

The active transmission line la (transmission line normally used) of the main system 1 and the backup transmission line 1b for the loop bank are connected in a ring shape through repeaters 32 and 33 of each node station. Here, the configuration of the repeater 32 will be explained. The repeater 32 includes an optical/electrical converter (0/E converter) 32a, a multiplexer (MPX) 32b, and an electric/optical converter (E10 converter) 32c. A signal input from the current transmission line 1a made of an optical fiber is converted into an electrical signal by an O/E converter 32a. This signal is input to the multiplexer 32b, and after processing such as data capture and amplification is performed, it is converted into an optical signal by the E10 converter 32c and sent onto the current transmission line 1a. The multiplexer 32b also includes a controller 3.
0 and RAM 31 are connected to the multiplexer 32b, and process and store data taken in by the multiplexer 32b.

Transmission and reception of messages between node stations 3m and 33 is as follows:
Since it is necessary to check the availability of the transmission path on the receiving side, this is done via the interface 34 in accordance with a predetermined protocol.

Note that, instead of the interface 34, an I10 interface of the data processing device is connected to the node station 3 that is connected to general data processing devices other than 3m and 3s.

FIGS. 2 and 3 are flowcharts showing the operations of the controllers of the operating node section 3b and the monitoring node section 3a.

First, the operation of the operational node section 3b in FIG. 2 will be explained.

Step nl (Hereinafter, step ni will be simply referred to as ni.

) via the working transmission line 1a (from the monitoring node unit 3a)
Wait until data message is received. When a message is received, it is determined whether this message is addressed to the local station (n
2). If the message is not addressed to your station, n? , n8, the message is sent to the next transmission path, and the message is sent back to the monitoring node unit 3a via the backup transmission path 1b. At n9, it is confirmed that no operation stop command has been sent from the monitoring node section, and the process returns to nl. When an operation stop command is sent, the operation is immediately finished.

On the other hand, if the message is addressed to your own station, store this message in RAM.
Buffering to 31 (n3) and at the same time n7 to n9
perform the following actions. Next, in order to transmit this message to the node station 3S on the subsystem 2 side, a message transmission request is output to the node station 3S (n4). It waits at n5 until it receives message transmission permission, and after receiving transmission permission, it transmits the data (n6) and returns to nl.

In addition, in FIG. 3, the monitoring node unit 3a waits until it receives the message from the working transmission line 1a (n1l), and buffers the received message in the RAM 31 (n12).
At the same time, this message should be sent to the operational node unit 3b.
13) It is determined whether a message will be returned after a certain period of time via the backup transmission path 1b (n14). If there is no reply, or if the returned messages are compared (n15) and there is a discrepancy (n16), the monitoring node unit 3a determines that the operation of the operational node unit 3b is abnormal and issues an operation stop command to the operational node unit 3b. After transmitting the data (n17), it starts its own operation mode operation (n18). If the returned data matches, it returns to nil.

n8 corresponds to the reply means of this invention, the RAM31 corresponds to temporary storage means of this invention, n15 and n16 correspond to comparison means of this invention, and n17 and nj8 correspond to emergency operation means of this invention. As described above, this example
Data collation was performed by bringing back the protection transmission path from the working transmission path, but in the case of a node station that connects the main system 1 and subsystem 2, return transmission via the protection transmission path was not performed (but The monitoring node unit can check for a match using the message transmitted from the subsystem 2 to the main system 1 by the operating node unit or the message transmitted from the main system 1 to the subsystem 2. In this case, the interface in FIG. 34 is provided separately in the monitoring node section 3a--operating node section 3d and in the monitoring node section 3C--operating node section 3b, respectively.

Further, in the above embodiment, when the operating node section is abnormal, the monitoring node section takes over and performs the operation mode operation, but the monitoring node section may simply have a reporting function. In this case, it is necessary to provide a data processing device or the like with a corresponding processing function.

(h1 Effects of the Invention As described above, according to the present invention, two node units capable of independently functioning as a node station are provided, one is operated as an operating node unit, the other is operated as a monitoring node unit, and the operating node When the operation of the node section becomes abnormal, the monitoring node section operates in its place.This makes it possible to immediately respond to abnormalities in the operating node section of the node station, and the node station and the entire system. reliability can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a node station of a local area network system according to an embodiment of the present invention, and FIGS. 2 and 3 are flowcharts showing the operations of the operating node section and the monitoring node section of the node station, respectively. , FIG. 4 is a diagram showing the configuration of a general ring type local area network system. ■-Main system, 2-Subsystem, 3-Node station, 30-Controller, 31-RAM. 32.33 - repeater, la, 2a - working transmission line, lb, 2b - protection transmission line.

Claims (1)

[Claims] (1) In a node station that connects two transmission lines of a circular local area network system having multiple transmission lines, monitoring is performed to monitor the operation of the operational node unit that operates in normal operation mode and the operational node unit. A node section is provided consecutively on the two transmission paths, and the operation node section receives a message from the monitoring node section via one transmission path to the monitoring node section via the other transmission path. A reply means for sending a reply is provided, and the monitoring node section includes a temporary storage means for temporarily storing the message received from one transmission path, and a message stored in the temporary storage means and a message returned from the operation node section. A node station for a local area network system, comprising: a comparison means for comparing; and a node station for a local area network system.