JPS6156539A - Control system for transmission line of ring-shaped network - Google Patents

Abstract

PURPOSE:To reconstitute of a system by switching connections among a transmission line and transmission and reception circuits at each node according to a fixed procedure in case both systems of duplicated transmission lines have abnormarities. CONSTITUTION:Each node contains interlocking changeover switches 4-0 and 4-1 and 8-1 and 8-0 respectively. Here ''0'' and ''1'' show a ''0'' system and a ''1'' system respectively. If abnormarities are detected with both systems, a monitor device delivers a loop-back command to each node. Thus each node carries out the next processing. The changeover switches are switched so that both systems ''0'' and ''1'' are connected with cross to each other at a node where the loop-back state is changed to the ''1'' system from the ''0'' system. In this case, the changeover switches at the input side of a ''0'' system repeating circuit are switched alternately and repetitively at a node where the inputs of both systems are cut off. These switching actions are discontinued when either one or both of both systems are normal. Then the monitor device gives an indication to a looped-back node to releqase this state when the fault of said node is recovered.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a transmission line system in a duplex ring network; in particular, the transmission line is used as a bidirectional transmission line, and switches are installed on both sides of each node. The ability to localize faults by establishing and cross-connecting transmission lines? This paper relates to a transmission line control method in a more sophisticated ring network.

[Conventional technology]

In a ring network, a large number of nodes are arranged on a transmission path formed in a loop, and communication between each node and each node and between a monitoring device (S"l) that monitors and controls each of these nodes, and between each node. It is something to do.

In conventional ring networks, in order to improve their reliability, two transmission paths with opposite transmission directions are provided as a redundant configuration, and the system is switched according to instructions from a monitoring device, which is a node that manages the network. A control method is used that performs loopback.

FIG. 7 shows the operation of a conventional ring network, where Sy indicates a monitoring device.

ND1 to ND5 are nodes, respectively.

In FIG. 7, (cLl indicates a state 7 in which the image transmission paths of the 0 and 1 systems are normal and the network is operated by the 0 system. Also, (bl is the node ND1).
．． This figure shows a state in which a failure has occurred in the 0-system transmission path between ND2, as indicated by the cross mark, so the systems are switched according to instructions from the monitoring device SV, and the 1-system is now in operation. Furthermore, (C1, because node ND2 has failed, node ND1,
A loopback is performed at ND5, and node ND2
indicates that it has been excluded from operation.

Furthermore, FIG. 8 shows a transmission line control method when a plurality of failures occur simultaneously in a conventional ring network. In the same figure, (α) is x between the monitoring device SY and nodes ND5 and nodes ND1°HD2.
The mark indicates a case where a failure has occurred. In this case, perform a loopback at node NDj as shown in (J). done, node ND'
l, HD5 is indicated to be removed from operation. On the other hand, (C) is 0 between the monitoring device Sy and the node NDj.
A case is shown in which a failure occurs in the system transmission path and the system 1 transmission path between the monitoring device SV and the node ND5, and in this case, it is impossible to reconfigure the system by loopback.

In a conventional ring network, if multiple failures occur on this uplink, multiple nodes may be excluded from the network, or the failure location (i.e., in the worst case, system reconfiguration will be impossible and system downtime will occur). I couldn't avoid it.

[Problem that the invention seeks to solve]

The present invention aims to make it possible to more highly localize nodes excluded from the network in the event of a failure in a duplex ring network 1.

[Means for solving problems]

In the method of the present invention, a switching circuit is provided between the transmission signal receiving circuit, the transmission circuit, and the transmission path at each node in the duplex ring network, and the monitoring device detects whether there is an abnormality in both systems. When detected, the network is reconfigured by loopback, and the node where loopback is performed from the first system to the second system transfers the transmitting circuit output of the first system to the second system. In the transmission line, the receiving circuit input of the second system is cross-connected to the transmission line of the first system, and at the node where the receiving input of both systems is disconnected, the receiving circuit side of the system 1 is The switch is repeatedly switched, and when the reception input from one or both systems becomes normal, the switching is stopped, and the node performing the loopback is released from the loopback when the failure situation improves.

[Effect]

According to the method of the present invention, in a duplex ring network, when both systems of the duplex transmission line are normal, operation is performed by the first system or the second system C2, and the active system is If there is an abnormality, the system switches to the other system, and if both systems are abnormal, the connection between the transmission path, transmitter circuit, and receiver circuit is switched at each node using a certain procedure. The system is reconfigured by doing this.

〔Example〕

FIG. 1 shows the basic configuration of a monitoring device and each node in an embodiment of the system of the present invention. In the figure, 1 is a data processing unit that processes a bit stream on a transmission path as necessary. Z-6,5-g
2- + + 3-1 are a receiving circuit and a transmitting circuit, respectively, forming an O-system relay circuit; 2- + + 3-1 are a receiving circuit and a transmitting circuit, respectively, forming a 1-system relay circuit. The 0-system and 1-system relay circuits can directly bypass and transmit the pit stream from the receiving circuit of each system to the transmitting circuit without going through the data processing section 1 under control from a control section (not shown). can. In addition, the receiving circuit 2-0 and the transmitting circuit 3-1 are connected to switching switches f4-g, 4-+t, and contacts s, -o and 5-1 or 6-1 and 6-0 (=
By switching, each 0-system transmission line 7-.

and the transmission line 7-1 of system 1:2, and vice versa. Similarly, receiving circuit 2-1 and transmitting circuit 3
-O means the corresponding changeover switch 8-1.8-
Connect G to contacts 10-1 and 10-0 or 9-o and 9, respectively.
By switching between -1 and ;2, they are connected to the transmission line 11-1 of the 1 system and the transmission line 11-0 of the 0' system, or vice versa.

In the method of the present invention, based on the results of monitoring the status of both systems by the monitoring device, based on the above-mentioned configuration,
The system is controlled based on the following rules.

(1) When both systems are normal, system 0 or system 1 is used as the active system and the other system is used as the backup system.

(1:) When an abnormality is detected in one of the systems, if it is the active system, an instruction is given to switch the active system in the monitoring device and each node, and the backup system is activated. operate.

(II+3 If an abnormality is detected in both systems, reconfigure the systems using the following procedure.

(() Performs loopback processing at each node.

That is, the monitoring device issues a loopback command to each node, whereby each node inputs the receiving circuit output to the transmitting circuit on the same side to perform loopback. Next, the monitoring device issues a command to each node to cancel the loopback if the inputs of both systems are normal as a result of the loopback. As a result, each node performs loopback release processing, so that loopback is finally performed at the node closest to the failure location. Regarding this kind of loopback processing method, please refer to the patent application filed in 1973.
It is explained in detail in No. 7-150480 (Japanese Unexamined Patent Publication No. 59-40739).

) Next, perform the following processing at each node.

(4) In a node that is in a loopback state from system 0 to system 1, the output of the transmission circuit of system 0 is connected to the transmission path of system 1), and the input of the reception circuit of system 1 is connected to the transmission path of system 0. Change the changeover switch so that the connections cross each other.

(b) At this time, at the node where the inputs of both systems are in a disconnected state, the input side of the 0 system relay circuit; the changeover switch at 2 is repeatedly switched (alternately at a certain time interval) twice,
As a result, when the input of either one or both systems becomes normal (=), the switching operation is stopped in this state.

Note that the processes (a) and (b) above for J2 are performed autonomously in each node.

(q After that, when the fault condition improves, the node performing loopback notifies the monitoring device of this.) (=Therefore, the monitoring device instructs the node performing loopback to release the loopback T Ru.

The node that receives the η instruction cancels the loopback and operates in this state from now on.

Hereinafter, specific examples of the operation of the system of the present invention at the time of failure in various cases will be explained. In the following figures, SV represents a monitoring device, and ND1 to ND5 represent five nodes forming the ring network fL' together with the monitoring station SV. Further, in the monitoring station SY and the nodes ND1 to ND5, the > mark indicates a receiving circuit, and the mark 1 indicates a transmitting circuit, and the outer one constitutes a 0-system relay circuit, and the inner one constitutes a 1-system relay circuit. Furthermore, among the lines connecting the monitoring station and each of the nodes ND1 to HD5, the outer lines indicate 0-system transmission lines, and the inner lines indicate 1-system transmission lines.

FIG. 2(α) to FIG. 2(d) illustrate the operation when a transmission path disconnection occurs between two different nodes. Now, the 0-system transmission path between node ND1 and node ND2 and the 1-system transmission path between node ND5 and node ND4 are shown by x marks: a break in the bivalent transmission path occurs, and as a result, node ND2 ~ It is assumed that synchronization has occurred at the input of the 0-system receiving circuit of HD5 and the 1-system receiving circuit input of nodes ND4 to ND1 as shown by the mark (second
Figure (α)). The monitoring device SV detects the occurrence of a failure in both systems and instructs each node ND1 to ND5 to perform loopback processing. As a result, each node performs loopback, and when the inputs of both systems are normal, the monitoring device S
Loopback according to Y instruction? However, in this case, loopback will be performed at nodes ND1 and ND5, which are very close to the failure location. In Figure 2, is LPBK being looped back? It shows. Next, node ND1, which is performing loopback from system 0 to system 1, switches the switching switch ft to connect the transmission circuit of system 0 and the reception circuit of system 1 to the transmission path of system 1 and the transmission path of system 0, respectively. Replace it with a cross-connection. Furthermore, nodes ND2 to ND4 whose inputs to both systems are disconnected repeatedly switch the changeover switch on the 0 system input side to perform system hunting (second
Figure (A)). As a result, when the input to either one or both systems becomes normal, the switching operation is stopped. In this case, the connection between the transmission line and the transmitting/receiving circuit is crossed on the 0-system input side of nodes -ND2 to ND4, resulting in the state shown in FIG. 2(C). After that, node ND1 which was performing loopback 3. N
When D5 detects failure recovery, it is sent to the monitoring device SV.
In response to the instruction from the monitoring device SV (-, the loopback is canceled. As a result, the process is terminated and the process shown in Fig. 2 (
The state shown in d) is reached, and the 0 system is operated. In each of the above figures, for example, 00. Display of IX etc.
0 system is normal.

System 1 shows an abnormal condition.

FIG. 3(α) to FIG. 6(C) show the operation when a transmission line disconnection occurs on both sides of a certain node. As shown in FIG. 3 (α), a break in the transmission line occurs in the transmission line of the 0 system input and 1 system input of node ND5, and as a result, the 1 system input of nodes ND1 to HD5, and the nodes ND5 to N
It is assumed that synchronization has occurred at the 0 system input (=) of D5. In this case, the nodes ND2 on both sides of the faulty node ND5
, ND4EX performs loopback, and at the node ND2, the 0-system transmitting circuit and the 1-system receiving circuit are cross-connected to the 1-system and 0-system transmission paths, respectively.

Further, in the node ND5, switching is performed by the changeover switch on the 0-system input side, and the switching operation is stopped when the 0-system input becomes normal (FIG. 3(b)). Then node ND2. Release the loopback in NDa,
The 0 system is operated in the state shown in FIG. 5 (cl).

FIG. 4(α) to FIG. 4(C) show the operation when the transmission line is disconnected between one side of the monitoring device and a certain node. As shown in FIG. 4(α), the system 1 output side of the monitoring device SV and the node ND1. A break in the transmission path occurs in the transmission path between ND2, and as a result, nodes ND2 to ND
It is assumed that synchronization has occurred in the D optical input of No. 5 and the 1 system input of nodes ND5 to ND1.

In this case, a loopback is performed at the node ND1, and the 0-system transmitting circuit and 1-system receiving circuit of the node ND1 are cross-connected to the 1-system and 0-system transmission paths, respectively (Fig. 4(b)). ). Thereafter, the loop bank is released at the node ND1, and the 0 system is operated in the state shown in FIG. 4(c)-2.

Figure 5 (α), Figure 1 (h+) shows the operation when the transmission line is disconnected on both sides of the monitoring device.As shown in Figure 5 (α), the O system of the monitoring station SV A break in the transmission line occurs between the output side of the 1st system and the receiving circuit of the nodes MD1 and ND2, respectively, and as a result, synchronization occurs at the O optical input of the nodes ND1 to ND5 and the 1st system input of the nodes ND5 to ND1. Assume that a disconnection has occurred.In this case, both thread inputs are disconnected at the monitoring device SY and nodes ND1 to ND5, so hunting is performed by switching the changeover switch on the 0 system input side at these locations. (However, only the monitoring device EV changes the changeover switch on the O system output side).

As a result, the 0 system output side of the monitoring device Sy and the node ND1
) Cross-connection is performed on the 0 system input side, and the diagram 's5 (
The state shown in b) is reached, and the 0 system is operated. - Figures 6 (α) to (cL) explain the system configuration establishment operation when a double failure occurs. For example, as explained in FIG. 2, FIG. 6(α) shows nodes ND1 and N
D2. A transmission path is generated in ND4 and HD5, and loopback is performed under the control shown in FIG. 2 (α) j (A), <0) j (d).

Control of changeover switch? After that, is the transmission path normal? This shows a case where a failure occurs between nodes ND2 and ND5 even though the system has been established and is operating normally.

At this point, the effective transmission path from node ND2 to HD5 is disconnected (indicated by ■ in the diagram), and a new C node ND5
, NDa, sends the 0 system human-powered reception circuit of ND5 and a monitoring command, and sends the node ND1. By performing loopback (LPBK) in each ND5, the minimum normal system configuration is achieved (FIG. 6(b)). Therefore, each node N
D5, NDa performs control to switch the changeover switch on the side where synchronization has been detected, and each node ND5゜NDa
Attempt to see if a normal route is formed.

If even one normal route can be established, a stable state will be reached (FIG. 6 (C1). After that, node ND1.
By canceling the loopback of the HD 5, one normal route can be formed and all nodes can enter the operational state in a loop (FIG. 6(d)).

According to the present invention, the same location 1 of the 2-system transmission line.

In the event of a disconnection, loopback control allows the most effective transmission path to be formed and the operational state to be maintained even if the disconnection occurs at different locations in each system.

〔Effect of the invention〕

As explained above, according to the method of the present invention, when there is an abnormality in both the first system and the second system.

Since the system is reconfigured by switching the connection between the transmission path and the transmitting circuit and receiving circuit at each node according to a certain procedure, it is possible to localize the failure point with higher accuracy, thus increasing the reliability of the system. sex.

Serviceability can be dramatically improved.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the basic configuration of a monitoring device and each node in an embodiment of the method of the present invention, and Fig. 2 (α) to Fig. 2 Tdl show cases in which a transmission path disconnection occurs between two different nodes. Figure 5 (α) to Figure 3 rC
+ is a diagram showing the operation when a transmission line disconnection occurs between one side of a certain node C:, and Figure 4 (α) to Figure 4 (c+ is a diagram showing the operation when a transmission line disconnection occurs between one side of a monitoring station and a certain node). Fig. 5 (α) is a diagram showing the operation when a transmission line disconnection occurs on both sides of the monitoring station, and Fig. 6 (α) - Figure 6(d) is a diagram showing the operation when a double failure occurs in the transmission path, Figure 7 is a diagram showing the operation of a conventional ring network, and Figure 8 is a diagram showing the operation of a conventional ring network. It is a diagram showing a transmission line configuration control method when failures occur simultaneously. 1... Data processing unit, 2-0... Receiving circuit forming the 0 system relay circuit, 3-O...0 Transmission circuit configuring the system relay circuit, 2-1... Receiving circuit configuring the 1-system relay circuit, 6-1... Transmission circuit configuring the 1-system relay circuit, 4
-or4-1...Switching switch t, 5-Os 5-1
t 6-O56-1...Contact, 7-a...0 system transmission line, 7-1...1 system transmission line, a-O, a-+...Switching switch t, 9-a , 9-1゜1o-o, 10-1
...Contact, 11-o...0 system transmission line, 11-1...
・1 system transmission line, Sy...monitoring device, ND1 to ND5・
··node

Claims (1)

[Claims] In a duplex ring-shaped network in which a monitoring device and a plurality of nodes are connected in a ring shape through two transmission paths consisting of a first system and a second system capable of bidirectional transmission, each A changeover switch is installed on both sides of each node to enable connection between the receiving circuit, the transmitting circuit, and the transmission line in each node and the two transmission lines, allowing loopback when a fault is detected in both systems. After the network is reconfigured by
cross-connect the transmitting circuit output of the system to the transmission line of the second system, the input of the receiving circuit of the second system to the transmission line of the first system,
At a node where the reception input from both systems is disconnected, the switch on the receiving circuit side of the first system is repeatedly switched, and the switching is stopped when the reception input from one or both systems becomes normal. , a transmission line control method in a ring network, characterized in that a node performing loopback releases the loopback when the failure situation improves.