JPH0650871B2 - Transmission line control method in ring type network - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a transmission line system in a duplicated ring network, and in particular, the transmission line is used as a bidirectional transmission line and switches are provided on both sides of each node. The present invention relates to a transmission line control method in a ring network in which the ability to localize a fault by providing a cross connection of transmission lines is further enhanced.

[Conventional technology]

In the ring type network, a large number of nodes are arranged on a transmission line formed in a loop, and communication is performed between each node and a monitoring device (SV) that monitors and controls these nodes, and between each node. It is a thing.

In order to improve the reliability of the conventional ring-type network, two transmission lines with mutually opposite transmission directions are provided as a redundant configuration, and instructions are sent from the monitoring device, which is a node that manages the network. Then, it adopts a control method that performs system switching and loop back.

FIG. 7 shows the operation of a conventional ring network, SV is a monitoring device, and ND1 to ND3 are nodes.

In FIG. 7, (a) shows a state in which both transmission lines of the 0-system and 1-system are normal and the network is operated by the 0-system. In (b), a failure occurred in the 0-system transmission line between the nodes ND1 and ND2, as indicated by the cross mark. Therefore, the system switching is performed according to the instruction from the monitoring device SV, and the 1-system operation is performed. It shows the state of being broken. further
(c) shows a state in which the node ND2 has failed, and therefore the nodes ND1 and ND3 are looped back according to an instruction from the monitoring device, and the node ND2 is excluded from operation.

Further, FIG. 8 shows a transmission line control method in the case where a plurality of failures occur simultaneously in the conventional ring type network. In the figure, (a) shows a case where a failure occurs between the monitoring device SV and the node ND3 and between the nodes ND1 and ND2, and in this case, a loop back is made at the node ND1 as shown in (b). This shows that the system is reconfigured by the operation between the monitoring device SV and the node ND1, and the nodes ND2 and ND3 are excluded from the operation. On the other hand, (c) shows a case where a failure occurs in the 0-system transmission line between the monitoring device SV and the node ND1 and the 1-system transmission line between the monitoring device SV and the node ND3. In this case, the system is reconfigured by loopback. Is impossible.

In this way, when multiple failures occur in the conventional ring network, multiple nodes are excluded from the network, or at the worst, system reconfiguration becomes impossible and system down occurs depending on the location of the failure. It was inevitable to become.

[Problems to be solved by the invention]

The present invention relates to a dual ring type network,
It is intended to allow the nodes excluded from the network at the time of failure to be highly localized.

[Means for solving problems]

In the system of the present invention, a plurality of nodes (ND1 to ND
5) and the monitoring device (SV) are the first in which the transmission directions are opposite to each other.
Are connected in a ring shape through a transmission line composed of the system and the second system, and each of the nodes (ND1 to ND5) serves as an input from the transmission line of one system to the transmission line of the other system. The monitoring device (SV) has a loopback means for looping back, and when it detects an abnormality in the reception signal received from the first system and the second system, it instructs the nodes (ND1 to ND5) to perform the loopback process. in duplexed ring Nets workpiece, said each node (ND1～ND5), receiver circuit connected to the transmission line of the first system (7- ₀₎ (2-
Inputs and the transmission path of the second system of _{0) (7-1} and the output of the transmission circuit _(3-1) connected to) each transmission path of the second system _(7-1) and the first a first switching switch for switching connection transmission path of the system to (7 _0), the reception circuit connected to the transmission line of the second system (11- ₁₎ (2
- ₁₎ inputs and an output of the transmission circuit (3 ₀₎ connected to the transmission line of the first system (11 ₀₎ of the first system transmission line, respectively (11 ₀₎ and second system transmission line (11 ₁₎ to provided a second switching switch for switching connection, when detecting the abnormality of the received signal from the two systems in the monitoring device (SV), each node (ND1～ND5) To each node (ND1) which sends a loop back instruction to the node, then sends a loop back release instruction for the first time, and receives the loop back instruction.
In ~ ND5), when the system that received the loop back instruction performs loop back to another system, and then receives the loop back release instruction, in the nodes (ND1 to ND5) that normally receive the received signal from both systems, The loop back state is released, and the loop back state is maintained in the one or two nodes (ND1 to ND5) in which the reception signal from each of the first system and the second system is abnormal. , The node 1 (ND1 of the 1 or 2 nodes (ND1 to ND5))
To ND5) switch-connect the second switching switch connected to the transmission line side that receives the abnormality, and do not receive the loop back instruction.
1 to ND5), the nodes (ND1 to ND5) that have detected an anomaly in the reception signals of both systems alternately switch the first switching switch and the second switching switch at predetermined time intervals. As a result, the switching operation is stopped when the reception signals of either one or both systems are synchronized and normal, and then the loop back state is maintained 1
Or, in the two nodes (ND1 to ND5), when the reception signal becomes normal in both systems, the one or two nodes (ND1 to ND5) can receive the monitoring device (SV) from the transmission paths of both systems. The monitoring device (SV) sends a second lube backing cancellation instruction for the second time, and one or two of the nodes (ND1 to N)
D5) releases the loop back state and reconfigures the system.

[Action]

According to the method of the present invention, in the duplicated ring network, when both systems of the duplicated transmission line are normal, operation is performed by the first system or the second system,
If the operating system is abnormal, switch to the other system, and if both systems are abnormal, follow a fixed procedure to connect the transmission line to the transmitting circuit and receiving circuit at each node. The system is reconfigured by switching the.

〔Example〕

FIG. 1 shows the basic configuration of the monitoring device and each node in one embodiment of the system of the present invention. In the figure, reference numeral 1 denotes a data processing unit, which processes a bit stream on a transmission line as needed. 2 _-0, 3 _-0 respectively receiving circuit constituting the relay circuit of the 0-system and the transmission circuit 2 _{-1,
Reference} numerals 3 _-1 are a receiving circuit and a transmitting circuit, respectively, which form a relay circuit of the 1 system. The 0-system and 1-system relay circuits can directly transmit the bit stream from the receiving circuits of the respective systems to the transmitting circuit without passing through the data processing unit 1 under the control of a control unit (not shown). it can. First
The 0-system output and 1-system input switches and the 1-system output and 0-system input switches shown in FIG. The receiving circuit 2 _-0 and the transmitting circuit 3 _-1 are interlocked with switching switches 4 _-0 , 4 respectively.
_-1 to the contact points 5 _-0 , 5 _-1 or 6 _-1 and 6 _-0 , respectively, to connect to the 0-system transmission line 7 _-0 and the 1-system transmission line 7 _-1 , respectively. It is designed to be connected in reverse. Similarly, the receiving circuit 2 _-1 and the transmitting circuit 3 _-0 have interlocking switching switches 8 _-1 , 8 _-0 and contact points 10 _-1 , respectively.
By switching to 10 _-0 or 9 _-0 and 9 _-1 , it becomes possible to connect to the 1-system transmission line 11 _-1 and the 0-system transmission line 11 _-0 , respectively, or vice versa. ing. Although not shown in FIG. 1 in the monitoring device, the receiving circuits _2-0, 2
_2-1 signal break of a received signal, the synchronization loss, has a failure detection unit for detecting an abnormality of the received signal deviation or the like of the received frame, are monitoring of both systems state.

In the system of the present invention, on the premise of the above configuration, according to the monitoring result of the state of both systems in the monitoring device,
The system is controlled based on the following rules.

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

(ii) When an error is detected in one of the systems, if it is the active system, give an instruction to switch the active system in the monitoring device and each node, and operate by the standby system. .

(iii) If an abnormality is detected in both systems, reconfigure the system using the following procedure.

(B) Perform loop back processing at each node.

That is, the monitoring device issues a loop back command to each node, whereby each node inputs the output of the receiving circuit to the transmitting circuit on the same side to perform the loop back. Next, the monitoring device issues a command to each node to cancel the loop back when the inputs of both systems are normal as a result of the loop back. As a result, each node performs the loop back cancellation processing, and finally, the node closest to the failure point is loop backed. Regarding such a loop back processing method, Japanese Patent Application No. 57-
It is described in detail in 150480 (Japanese Patent Laid-Open No. 59-40739).

(B) Next, the following processing is performed in each node.

(A) At a node that is in a loopback state from 0 system to 1 system, the output of the 0 system transmission circuit intersects with the 1 system transmission line, and the input of the 1 system reception circuit intersects with the 0 system transmission line. Then, the switching switch is switched so that they are connected.

(B) At this time, at the node where the inputs of both systems are in the disconnected state, switching of the switching switch on the input side of the 0-system relay circuit is alternately repeated at a certain time, and either When the input of one system or both systems is normal,
The switching operation is stopped in this state. The above (A), (B)
Processing is autonomously performed in each node.

(C) After that, when the node performing the loop back becomes able to receive normally from the transmission line where the reception signal becomes abnormal due to line disconnection or the like, this is notified to the monitoring device. As a result, the monitoring device instructs the loop-backed node to release the loop back.

(D) The node that received the instruction releases the loop back, and thereafter operates in this state.

Hereinafter, specific operation examples of the method of the present invention at the time of failure in various cases will be described. In the drawings below, SV represents a monitoring device, and ND1 to ND5 exemplify five nodes that form a ring network together with the monitoring station SV. Further, in the monitoring station SV and the nodes ND1 to ND5, a mark indicates a receiving circuit, a mark indicates a transmitting circuit, and an outside one constitutes a 0-system relay circuit, and an inside one constitutes a one-system relay circuit. There is. Furthermore, of the lines connecting the monitoring station and each node ND1 to ND5, the outer one is 0, and the inner one is 1
The transmission line of the system is shown.

FIGS. 2 (a) to 2 (d) show the operation when a transmission line disconnection occurs between two different nodes.
Now, in the 0-system transmission line between the node ND1 and the node ND2 and the 1-system transmission line between the node ND5 and the node ND4, the transmission line disconnection occurs as indicated by the cross mark, and as a result, the 0-system transmission of the nodes ND2 to ND5 It is assumed that the input of the receiving circuit and the input of the 1-system receiving circuit of the nodes ND4 to ND1 are out of synchronization as shown by the crosses (Fig. 2 (a)). The monitoring device SV detects the occurrence of a failure in both systems and instructs the nodes ND1 to ND5 to perform the loop back processing. As a result, each node performs a loop back, and when the inputs of both systems are normal, the rule back is released by the instruction of the monitoring device SV. In this case, however, the loop back is eventually caused at the nodes ND1 and ND5 closest to the faulty part. Will be done. In Figure 2
LPBK indicates that a loop back is being performed.
Next, a node that is loopbacking from system 0 to system 1.
In ND1, the switching switch is switched to the 0 system transmitter circuit and 1
The system reception circuit is replaced with the 1-system transmission line and the 0-system transmission line, respectively, to perform cross connection. Further, the nodes ND2 to ND4, whose inputs are both disconnected, repeatedly switch the switching switches on the input side of the 0 system to hunt the system (Fig. 2 (b)). As a result, the switching operation is stopped when the input of either one or both systems becomes normal. In this case, the connection of the transmission line and the transmission / reception circuit is crossed on the 0-system input side of the nodes ND2 to ND4, and the state shown in FIG. After that, when the nodes ND1 and ND5 that have been looping back detect a failure recovery, this is notified to the monitoring device SV, and the loop backing is released according to an instruction from the monitoring device SV. As a result, the processing is terminated and the state shown in FIG. 2 (d) is reached, and the 0 system is operated. In each of the above figures, the indications such as 0∘, 1 ×, etc. added to the nodes ND1 to ND5 and the monitoring station SV indicate the states such that the 0 system is normal and the 1 system is abnormal.

FIGS. 3 (a) to 3 (c) show the operation when the disconnection of the transmission path occurs on both sides of a certain node. Third
As shown in Figure (a), the transmission line disconnection occurs in the transmission line of 0-system input and 1-system input of node ND3, and as a result, node ND1
It is assumed that out-of-synchronization occurs in the 1-system input of ~ ND3 and the 0-system input of nodes ND3 to ND5. In this case the faulty node
Loop backing is performed in the nodes ND2 and ND4 on both sides of ND3, and in the node ND2, the 0-system transmission circuit and the 1-system reception circuit are cross-connected to the 1-system and 0-system transmission paths, respectively. Further, at the node ND3, hunting is performed by the switching switch on the 0-system input side, and the switching operation is stopped when the 0-system input becomes normal (FIG. 3 (b)). After that, the loop back is released at the nodes ND2 and ND4, and the third
The 0-system is operated in the state shown in FIG.

FIGS. 4 (a) to 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 (a), the transmission line is disconnected in the transmission line between the 1-system output side of the monitoring device SV and the nodes ND1 and ND2, and as a result, the 0-system input and the node ND of the nodes ND2 to ND5.
It is assumed that out-of-synchronization occurs in the 1-system input of 5 to ND1. In this case, the loop back is performed at the node ND1 and the 0-system transmission circuit and the 1-system reception circuit of the node ND1 are cross-connected to the 1-system and 0-system transmission paths, respectively (FIG. 4 (b)). . After that, the loop back is released in the node ND1, and the 0 system is operated in the state shown in FIG. 4 (c).

FIGS. 5 (a) and 5 (b) show the operation when the transmission line is disconnected on both sides of the monitoring device. Fig. 5
As shown in (a), disconnection of the transmission line occurs in the transmission line between the output side of the 0-system and 1-system of the monitoring station SV and the reception circuits of the nodes ND1 and ND5, respectively, and as a result, 0 of the nodes ND1 to ND5
It is assumed that the system input and the 1-system input of the nodes ND5 to ND1 are out of synchronization. In this case, monitoring device SV, node
Since both ND1 to ND5 are disconnected from both systems, the switching switch on the 0 system input side is switched and hunting is performed on all of them (however, only the monitoring device SV switches the switching switch on the 0 system output side). The configuration of the monitoring device is basically the same as that of the node, as will be understood from the embodiments. However, it has a function of detecting an abnormality in a received signal from the two loop transmission lines, sending a loop back command to each node, and sending a release command by failure recovery. Since the present invention is originally characterized in that a switching switch is provided on the node side, the monitoring device naturally has a switching switch. As a result, the 0-system output side of the monitoring device SV and the 0-system input side of the node ND1 are cross-connected to the state shown in FIG. 5 (b), and the 0-system operation is performed.

FIGS. 6 (a) to 6 (d) explain the establishing operation of the system configuration when a double failure occurs. FIG. 6 (a) shows, for example, as described in FIG. 2, transmission lines are generated in the nodes ND1 and ND2, ND4 and ND5, respectively, and FIGS. 2 (a), (b), (c), (d) In the control shown in (1), the case where a normal transmission path is established through the control of the loop back and the switching switch and the system is operating normally and a failure occurs between the nodes ND2 and ND3 is shown.

At this point, the effective transmission line from node ND2 to ND3 is disconnected (see the figure (Indicated by a mark), when the receiving circuit of the 0-system input of the nodes ND3, ND4, and ND5 and the receiving circuit of the monitoring device SV newly detect loss of synchronization, the monitoring device SV sends a loopback command to the 0-system 1 system again By performing loop back (LPBK) on each of the nodes ND1 and ND5, the minimum normal system configuration is obtained (Fig. 6 (b)). Therefore, each node ND3, ND
In 4, control is performed to switch the changeover switch on the side where out-of-synchronization is detected, and it is tried whether or not a normal route is formed at each node ND3, ND4. If even one normal route can be established, it will settle into one stable state (Fig. 6 (c)). After that, by releasing the loop back of the nodes ND1 and ND5, one normal route can be formed and all the nodes can enter the operating state in a loop (Fig. 6 (d)).

According to the present invention, when a disconnection occurs at the same point of the 2-system transmission path, the maximum effective transmission path is established by the loopback control and even if the disconnection occurs at different locations in each system. Can be formed and maintained in an operational state.

〔The invention's effect〕

As described above, according to the method of the present invention, when an abnormality occurs in both the first system and the second system, the transmission line, the transmission circuit, and the reception circuit are received in each node by a certain procedure. Since the system is reconfigured by switching the connection with the circuit, the location of the failure can be localized with higher accuracy, and the reliability and serviceability of the system can be dramatically improved. .

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of a monitoring device and each node in one embodiment of the system of the present invention, and FIGS. 2 (a) to 2 (d).
Shows the operation when a transmission line break occurs between two different nodes. Figures 3 (a) to 3 (c) show the operation when a transmission line break occurs on both sides of a node. FIG. 4 (a) to FIG. 4 (c) are diagrams showing the operation when a disconnection of the transmission line occurs between one side of the monitoring station and a certain node, FIG. 5 (a), and FIG. Figure (b) is a diagram showing the operation when the transmission line is disconnected on both sides of the monitoring station, and Figures 6 (a) to 6 (d) show the case when a double failure occurs in the transmission line. FIG. 7 is a diagram showing the operation, FIG. 7 is a diagram showing the operation of a conventional ring network, and FIG. 8 is a diagram showing a transmission line configuration control method when a plurality of failures occur simultaneously in the conventional ring network. is there. 1 ...... the data processing unit, 2 _-0 ...... 0-system receiving circuit constituting the relay circuit, 3 _-0 ...... 0 system transmitting circuit constituting the relay circuit,
2 _-1 ...... Reception circuit that constitutes 1-system relay circuit 3 _-1 ...... 1
Transmitter circuit constituting system relay circuit, 4 _-0 , 4 _-1 ... switching switch, 5 _-0 , 5 _-1 , 6 _-0 , 6 _-1 ... contact point, 7 _-0 ... 0
System transmission line, 7 _-1 ...... 1 system transmission line, 8 _-0 , 8 _-1 ... Switching switch, 9 _-0 , 9 _-1 , 10 _-0 , 10 _-1 ...... Contact, 11 _-0 ...... 0
System transmission line, 11 _-1 ...... 1 system transmission line, SV ... monitoring device, ND
1 to ND5 ... node

Claims (1)

[Claims] 1. A plurality of nodes (ND1 to ND5) and a monitoring device (SV) are connected in a ring shape via a transmission path composed of a first system and a second system whose transmission directions are opposite to each other, and Each of the nodes (ND1 to ND5) has a loop back means for returning an input from a transmission line of one system as an output to a transmission line of the other system, and the monitoring device (SV) has the first system and the second system. In the duplicated ring network for instructing the loop back processing to each of the nodes (ND1 to ND5) when the abnormality of the received signal received from the system is detected, the first to each of the nodes (ND1 to ND5) system transmission line receiver circuit connected to a (7 ₀₎ of (2-
Inputs and the transmission path of the second system of _{0) (7-1} and the output of the transmission circuit _(3-1) connected to) each transmission path of the second system _(7-1) and the first a first switching switch for switching connection transmission path of the system to (7 _0), the reception circuit connected to the transmission line of the second system (11- ₁₎ (2
- ₁₎ inputs and an output of the transmission circuit (3 ₀₎ connected to the transmission line of the first system (11 ₀₎ of the first system transmission line, respectively (11 ₀₎ and second system transmission line (11 ₁₎ to provided a second switching switch for switching connection, when detecting the abnormality of the received signal from the two systems in the monitoring device (SV), each node (ND1～ND5) To each node (ND1) which sends a loop back instruction to the node, then sends a loop back release instruction for the first time, and receives the loop back instruction.
~ ND5), the system that received the loop back instruction performs loop back to another system, and then receives the loop back release instruction, the nodes (ND1 to ND5) that normally receive the received signal from both systems, , The loop back is released, and the loop back state is maintained in one or two nodes (ND1 to ND5) in which the reception signal from each of the first system and the second system is abnormal. As it is, one of the one or two of the nodes (ND1 to ND5) is the one of the nodes (ND1
To ND5) switch-connect the second switching switch connected to the transmission line side that receives the abnormality, and do not receive the loop back instruction.
1 to ND5), the nodes (ND1 to ND5) that have detected an anomaly in the reception signals of both systems alternately switch the first switching switch and the second switching switch at predetermined time intervals. As a result, the switching operation is stopped when the reception signals of either one or both systems are synchronized and become normal, and then the loop back state is maintained 1 or 2
In both of the nodes (ND1 to ND5), when the reception signal becomes normal in both systems, one or two of the nodes (N
D1 to ND5) notify the monitoring device (SV) that reception is possible from the transmission paths of both systems, and the monitoring device (SV) sends a second loop back cancellation instruction to send one or two The nodes (ND1 to N
D5) is a transmission line control method in a ring network, which is for releasing the loop back state and reconfiguring the system.