JPS60182242A - Loop communication system constituting method - Google Patents

Abstract

PURPOSE:To keep the communication by using one transmission line connecting nodes and a transmission line connecting nodes at an interval of one node or plural nodes to duplicate the transmission lines and passing through a supervisory node generated with a fault or a node. CONSTITUTION:The supervisory node 20 and nodes 20-29 of a loop communication system are connected by an optical cable 30, the supervisory node 20 and nodes 22...24...28 are connected by an optical cable 31 and nodes 21...23...29 are connected by an optical cable 32 so as to constitute a duplicated loop. The cable 30 is connected to a terminal A of the nodes 21-29, the cable 31 or 32 is connected to a terminal B, the optical signal is converted into an electric signal by O/E converter circuits 35, 36 and fed to a switch circuit 39. The electric signal is outputted to terminals C, D by E/O converting circuits 37, 38 connected to the cable 30, 31, 32 by the control of the control circuit 41 by using the circuit 39. The communication is kept by bypassing the supervisory node 29 or the nodes 21-29 in fault.

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention relates to loop communication in which devices (called nodes) connected to a duplex transmission path configured in a loop using optical cables communicate with each other. The present invention relates to a loop communication system configuration method that improves the reliability of a loop communication system by preventing communication between healthy nodes from being interrupted even if a failure occurs in a plurality of nodes.

(b) Prior Art and Problems FIG. 1 is a diagram illustrating a configuration example of a duplex loop communication system using optical cables. 1 is the monitoring node and 2
~10 are nodes. Signals are transmitted in the directions shown by the arrows to the optical cables that connect each node, and communication between the nodes is performed. FIG. 2 shows an example of a frame structure for transmitting communication signals.

Reference numeral 11 denotes a frame header used for communication between each of the nodes 2 to 10 and the monitoring node 1. Time slots 12 to 16 carry data used for mutual communication among the nodes 2 to 10. For example, when communicating from node 2 to node 6, it first sends a frame to monitoring node 1, and uses the frame header 11 at the beginning of the frame to notify that it wants to communicate with node 6. Monitoring node 1 sends a frame to node 6. The contents of the data source 11 are analyzed and the frame header 11 instructs the nodes 2 and 6 to communicate using, for example, the time slot 12. Also, for example, the node 3 instructs the monitoring node 1 to transmit data to the nodes 7 and 8. When notified, monitoring node 1 notifies nodes 3.7 and 8 to communicate using time slot 13. In this case, communication between nodes 2 and 6 and communication between nodes 3 and 7. Since each node uses a different time slot, there is no problem with mutual communication.

For example, if nodes 5 and 9 fail at the same time, or if one node fails while the other node fails, monitoring node 1 detects this failure and instructs nodes 4 and 10 to Fold back the optical cable and connect it. Communication between the remaining nodes 2, 3, 4, and 10 is then enabled. However, even if the nodes 6, 7, and 8 are healthy, they cannot communicate because signal transmission with the monitoring node 1 that controls communication is interrupted. As described above, the conventional duplex loop communication system has the disadvantage that when a plurality of nodes become impaired, there will be a section where communication between healthy nodes will not be possible despite the duplication.

(c) Object of the Invention In view of the above-mentioned drawbacks, the object of the present invention is to provide a path that connects every other monitoring node and nodes constituting a loop communication system, and to communicate by passing a faulty monitoring node or node. An object of the present invention is to provide a method for configuring a loop communication system that can maintain the following.

(d) Configuration of the Invention The configuration of the present invention is a loop communication system that communicates between a plurality of nodes connected to a transmission path configured in a loop, one transmission path connecting each node, The transmission path is made redundant by using a transmission path that connects every other node or every other node.

(Fll) Embodiment of the Invention FIG. 3 is a block diagram of a loop communication system showing an embodiment of the present invention. From the monitoring node 20 to the nodes 21, 22,
23, 24, 25, 26, 27°28.29, respectively, and the monitoring node 20 to the node 22.
．． an optical cable 31 that connects 24, 26, and 28, respectively;
A duplex loop is constructed with optical cables 32 connecting the nodes 21.degree. 23.25 and 27.29, respectively. If each node is operating normally, the second
Communication is performed by transmitting the frame shown in the figure.

For example, if a failure occurs in nodes 24 and 28, the optical cable 32 is used to pass between the nodes 24 and 28, and the optical cable 30 is used to form a transmission path between the other nodes to maintain communication with the other nodes. You can. Also, for example, when nodes 25 and 27 have a failure, the optical cable 31 is used to pass between the nodes 25 and 27, the optical cable 30 is used to form a transmission path between the other nodes, and the other nodes can maintain communication. I can do it.

FIG. 4 is a block diagram of a node circuit used in the present invention. Terminal A is connected to, for example, an optical cable 30 , and an optical signal enters an O/E conversion circuit 35 , where it is converted into an electrical signal and sent to a switching circuit 39 .

The switching circuit 39 sends this signal to the E10 conversion circuit 37 under the control of the control circuit 41, and the E10 conversion circuit 37 converts the electrical signal into an optical signal and sends it to the optical cable 30 from the terminal C. At this time, the high-speed conversion circuit 40 copies the frame from the switching circuit 39, takes in the necessary frame header signal or time slot data, and sends it to the control circuit 41.

Terminal B is connected to, for example, an optical cable 31 or 32, and the optical signal is converted into an electrical signal by an O/E conversion circuit 36 and input to a switching circuit 39. The switching circuit 39 sends the output of the 07E conversion circuit 36 to the E10 conversion circuit 38.
8 converts this output into an optical signal and sends it to the optical cable 31 or 32 from the terminal. For example, when a failure occurs in the node 22, the control circuit 41 of the adjacent node 21 analyzes the signal sent by the monitoring node 20 on the frame header, controls the switching circuit 39, and controls the O/E conversion circuit 39.
5 is connected to the E10 conversion circuit 38. Further, the control circuit 41 of the node 23 is similarly connected to the O/E conversion circuit 36.
The output of the E10 converter circuit 37 is connected to the E10 converter circuit 37. Therefore, the nodes 21 and 23 are connected by an optical cable 32, and the other nodes are connected by an optical cable 30. Therefore, even if, for example, an abnormal signal is sent from the node 22, the output of the O/E conversion circuit 35 of the node 23 is blocked by the switching circuit 39, so that the nodes after the node 23 are not affected. In this way, the node 22 where the failure has occurred will be passed over by the optical cable 32.

In this embodiment, every other node is connected, but it is also possible to connect every other node, such as every second node.

(f) As described in detail, the present invention can ensure healthy communication between nodes in a duplex loop communication system even if a plurality of nodes fail. Also, while a failed node is being repaired, other nodes can be used as they are.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating an example of the configuration of a duplex loop communication system using optical cables, FIG. 2 is a diagram illustrating an example of a frame configuration for transmitting communication signals, and FIG. FIG. 4 is a block diagram of a node circuit used in the present invention. 1.20 is the monitoring node, 2, 3.4.5, 6°7.8,
9, 10, 21, 22, 23, 24, 25. 26, 27
, 28 and 29 are nodes, 35 and 36 are O/E conversion circuits,
37 and 38 are E10 conversion circuits, 39 is a switching circuit, 4o is a high-speed conversion circuit, and 41 is a control circuit.

Claims (1)

[Claims] A loop communication system that communicates between a plurality of nodes connected to a transmission path configured in a loop, in which every other node or every other node is connected to one transmission path that connects each node. 1. A method for configuring a loop communication system characterized by duplicating a transmission path using a transmission path.