JPH01305638A - Control system for loop type network - Google Patents

Abstract

PURPOSE:To prevent system down even at the time of a double trouble by providing a jump transmitting path to execute data transmission with jumping an adjacent node. CONSTITUTION:A double loop is obtained by a present use system transmitting path 3-1 and an auxiliary system transmitting path 3-2 and a loop type network is constituted by executing connection so as to jump the node by a jump transmitting path 3-3. When trouble generation is detected in a supervising node 1, respective nodes 2-1 to 2-n are controlled and operation is switched from a present use system to an auxiliary system by a switching circuit 5 or a returning route is formed by a returning circuit 4. When data can not be transmitted through the auxiliary system transmitting path 3-2, control is executed to switch to the jump transmitting path 3-3. Thus, the system down is not generated by the troubles in the plural spots of the transmitting path or by the troubles of the plural nodes and reliability can be improved.

Description

[Detailed Description of the Invention] [Summary] To prevent system down even in the event of double failure, regarding a control method for a loop type network in which data transmission is performed by connecting a plurality of nodes through a loop-shaped transmission path. For the purpose of this, a monitoring node and a plurality of nodes are connected in a loop for a working system and a backup system, and a skip transmission path is provided for performing data transmission by skipping over adjacent nodes, and the node is equipped with: A loopback circuit that loops back data from the working transmission line and sends it out to the protection transmission line, and a switching circuit that switches to transmitting and receiving data via the skip transmission line, are provided, and when a failure occurs, the monitoring node is switched from the monitoring node to the healthy node and So that a return route or a round route is formed through the transmission line,
The turnback circuit or the switching circuit is controlled to continue data transmission.

(Industrial Application Field) The present invention relates to a control system for a loop network that connects a plurality of nodes through a loop-shaped transmission path to transmit data.

A loop-type network 1 is known in which nodes each accommodating a terminal device are connected to a monitoring node by a loop-shaped transmission path. In such a network, it is desired to be able to continue data transmission using healthy nodes and transmission paths even if a failure occurs in some nodes or transmission paths.

[Conventional technology]

For example, as shown in FIG. 12, the conventional loop network includes a monitoring node F'51 and a plurality of nodes 52-1.
~51-5 (in the case of five nodes) are connected in a loop through the working transmission line 53-1 and the protection transmission line 53-2, and each node 52-1 to 52-5 is accommodates any number of terminal devices. In addition, the transmission lines 53-1 and 53-2 for the active system and backup system are constructed of twisted pair wires or coaxial wires when transmitting data using electrical signals, and are constructed using optical fibers when transmitting optical signals. configured. When transmitting by optical signals, the monitoring node 51 and each of the nodes 52-1 to 52-5 are provided with photoelectric conversion and electro-optical conversion functions.

The monitoring node 51 sends timing signals such as synchronization signals and monitors the network. For example, if a failure such as a power cut occurs in the node 52-3,
Since the monitoring node 51 cannot receive signals such as timing signals through the loop route of the active transmission line 53-1, it determines that a failure has occurred. Then, loop circuits are formed in order from the closest node, and it is checked whether a loop is formed by the working transmission line 53-1 and the protection transmission line 53-2.

Since it is not possible to form a return circuit in the faulty notebook, the return circuit 54-2 is formed in the notebook 52-2 and 52-4.
．． 54-4 is formed, the failed node 52-3 is separated under the control of the monitoring node 51, and data transmission can be performed between other nodes.

For example, if a failure occurs in the active transmission line 53-1 between No. 1" 51-2.52-3, the backup transmission path 53
-2 can be used to continue data transmission. In this case, the backup transmission line 53 between nodes 52-2 and 52-3
If a failure also occurs in node 52-2, a loop will not be formed from the perspective of the monitoring node 51, so the loop circuits described above will be formed in order, and the loop circuits will be formed at nodes 52-2 and 52-3. By doing so, data transmission can be continued.

[Problem to be solved by the invention]

In the conventional loop type network, nodes are connected by a double transmission path of a working transmission line 53-1 and a protection transmission line 53-2, and in the event of a failure, a backup transmission line is connected from the working transmission line 53-1. Data transmission can be continued by switching to the system transmission path 53-2 or by forming a return circuit to isolate the faulty part. However, if a double failure occurs in a node, for example, as shown in FIG. 13, if a failure occurs in node 52-2. 54 and 54-5, the nodes 5 including the monitoring node 51
Although data transmission can be performed between nodes 52-1 and 52-5, the failed node 52-2 and the normal node 52-3 between 52-4 are disconnected from the network. That is, even if the node is normal, data transmission cannot be continued.

An object of the present invention is to prevent the system from going down even in the event of double failure.

[Means to solve the problem]

The loop network control method of the present invention allows data to be transmitted over faulty nodes, and will be explained with reference to FIG.

A working transmission line 3-1 and a protection transmission line 3- connect the monitoring node 1 and a plurality of nodes 2-1 to 2-n in a loop.
2 and a skip transmission line 3-3 for performing data transmission by skipping adjacent nodes, and each node 2-1 to 2-n
Then, the data from the working transmission line 3-1 is transferred to the protection transmission line 3.
-2 and 6) and a switching circuit 5 for switching data transmission and reception via the interlaced transmission line 3-3.

When a failure occurs, a return route or a round route is formed from the monitoring node 1 via healthy nodes and transmission lines.
Controls the return circuit 4 or switching circuit 5 to control data transmission.
! Continue.

[Effect]

When there is a failure in the active transmission line 3-1, data transmission is continued by switching to the protection transmission line 3-2, and when a node 1 has a serious failure, a skip transmission line 3-3 that skips over the failed node;
Data transmission is continued using the protection transmission line 3-2 or the working transmission line 3-1. In addition, in the event of double node failure, if the failed nodes are adjacent, a return route is formed using the return circuit 4 at the node adjacent to the two failed nodes, and a healthy node is sandwiched between the two failed nodes. If there are two failed nodes, data transmission is continued by forming a loop route using the skip transmission path 3-3 that skips over each failed node.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a block diagram of main parts of a notebook according to an embodiment of the present invention, in which 11 is a transmission/reception processing control section including a processor, etc.;
2-1 to 12-3 are transmitting/receiving units for the active system, protection system, and intermittent system, 13-1 to 13-3 are transmission lines for the active system, protection system, and intermittent system, 14 is a return circuit, and 15 is a switching circuit. be.

The feedback circuit 14 is controlled by the transmission/reception processing control unit 11 according to a command from a monitoring node (not shown), and transfers data received by the active transmission/reception unit I2-1 from the backup transmission/reception unit 12-2 to the backup system. This is a switch circuit composed of transistors and the like for sending out data to the transmission line 13-2. The switching circuit 15 is composed of a transistor or the like, and the transmission/reception processing control section 11 switches the transmission/reception sections 12-1, 12-2 based on a command from the monitoring node and in synchronization with each node. The transmission/reception unit 12-3 is switched based on the judgment of the transmission/reception processing control unit 11 itself.

The transmission and reception processing control unit 11 includes transmission and reception units 12-1 to 12-3.
It has a function of not only monitoring the data received by the transmitting/receiving section and operating the return circuit 14 and the switching circuit 15, but also multiplexing the data received from the transmitting/receiving section and transmitting the multiplexed data to the transmitting/receiving section.

The transmitting/receiving units 12-1 to 12-3 are connected to each transmission line 13-1 to 13-1.
3-3, and each transmission line 13-1~
13-3, and it is also possible to provide a data destination identification function to immediately send data that is not addressed to the own node. Further, the destination can be identified in the transmission/reception processing control section 11, and data not addressed to the own node can be simultaneously transmitted from each of the transmission/reception sections 12-1 to 12-3.

In this embodiment, when the active transmission line 13-1 and each node are normal, the active transmission line 13-1 transmits data, and the protection transmission line 13-2 transmits only timing signals, etc. do. Further, when switching to the protection transmission line 13-2 and transmitting data, the data is also sent to the skip transmission line 13-3. That is, when the switching circuit I5 selects the received data of the transmitting/receiving section 12-2 and transfers it to the transmitting/receiving processing control section 11, the transmitting/receiving section 12-2゜12-
3 to backup transmission line 13-2 and skip transmission line 13-3
Also, when the switching circuit 15 selects the received data of the transmitter/receiver 12-3 and transfers it to the transmitter/receiver processing controller 11, the transmission/receiver 12-2. and the interlaced transmission line 13-3.

FIG. 3 is an explanatory diagram of a network according to an embodiment of the present invention, in which the monitoring node 10 and the nodes 20-1 to 20-5 are connected to the active transmission line 13-1 and the protection transmission line 13-2. The connection is made in a loop, and the connection is made by skipping adjacent nodes by the skip transmission line 13-3. Also, the transmission direction by the working transmission line 13-1 and the protection transmission line 13-
2, and the transmission direction by the skip transmission line 13-3 may be the same as the transmission direction of either the working transmission line 13-1 or the protection transmission line 13-2. , shows the case where the direction is the same as that of the protection transmission line 13-2.

Working transmission line 13-1 and each node 20-1 to 20-5
If both are normal, data is transmitted using the active transmission line 13-1. That is, in each node 20-1 to 20-5, if the data received by the transmitting/receiving unit 12-1 is addressed to the own node, it is taken in, and if it is addressed to another node, it is directly sent to the active transmission path 13-1. Send. Therefore, a circular route is formed as seen from the monitoring notebook 10.

FIG. 4 is an explanatory diagram when a single failure occurs; for example, node 2
If a failure occurs in 0-3 due to a power outage or the like, the monitoring node 10 will be unable to receive the signal of the one-way route through the working transmission line 13-1, and therefore determines that a failure has occurred in the working transmission line 13-1. Then, it switches to the protection transmission line 13-2, and sends a switching command to switch from the active system to the protection system to each node 20-1 to 20-5. Each node controls the switching circuit 15 according to the switching command, and switches to select the data received by the standby transmission/reception unit 12 - 2 and transfer it to the transmission/reception processing control unit 11 .

However, since the failed node 20-3 does not operate, the node 20-2 downstream of the protection transmission line 13-2 cannot receive data, and the switching circuit 15 of that node 20-2 is unable to receive data. is controlled by the transmission/reception processing control unit 11 to switch so that data can be received via the interlaced transmission path 13-3. Therefore, among the data sent to the protection transmission line 13-2 and the interlaced transmission line 13-3 at the node 20-4, the data transmitted through the interlaced transmission line 13-3 is sent to the node 20-2. You will receive it. Therefore, a round route shown by a bold line is formed and data is transmitted.

FIG. 5 is an explanatory diagram when node double failure occurs, and node 20
-2. If a failure occurs in 20-5, as in the case described above, from the monitoring node 10 to each node 20-1 to 20-5
A switching command is sent to switch from the active transmission line 13-1 to the protection transmission line 13-2, and since nodes 2 (1, 2 (1-4) cannot receive data via the protection transmission line I3-2, they are skipped). The transmission path 13-3 is switched to receive data.Thereby, a loop path shown by a bold line is formed and data is transmitted.

Also, as shown in FIG. 6, the adjacent node 20-3.20
-4, the monitoring node 10 sends a switching command to each node 20-1 to 20-5 to switch from the active transmission line 13-1 to the protection transmission line 13-2, as in the case described above. Sending, node 20-2 is connected to backup transmission line 13-2
Since the data cannot be received by the skip transmission line 13,
-3, but since a failure has occurred in node 20-4, the skip transmission line 1 along with the protection transmission line 13-2
Node 2 cannot send data to node 3-3 either.
0-2, data through the interlaced transmission line 13-3 cannot be received either.

If the monitoring node 10 identifies that the one-round route by the protection transmission line 13-2 is not formed and the one-round route including the skip transmission line 13-3 is not formed by not being able to receive the one-round signal, the monitoring node 10 10 sends out a command to switch back from the protection transmission line 13-2 to the working transmission line 13-1, and also sends out a command to form a return circuit.

As a result, the return circuit 14 of the node 20-5 forms a return route to the monitoring node 10, indicated by a thick line, and the return circuit 14 of the node 20-2 forms a return route, indicated by a thick line, to the monitoring node 10. do. That is, node 2
0-2. At 20-5, the transmitter/receiver 12-1 receives the data transmitted via the active transmission line 13-1,
Received data addressed to other nodes is transferred to the transmitting/receiving section 12-2 via the return circuit 14 and sent to the backup transmission line 13-2.

Therefore, in the event of a failure in multiple locations on the transmission path or failure in multiple nodes, it is possible to continue data transmission using only healthy transmission paths and nodes.

FIG. 7 is a block diagram of main parts of a node according to another embodiment of the present invention, in which 21 is a transmission/reception processing control section, 22-L 21-
2 is a transmitting/receiving section, 23-1 is a working transmission line, 23-2 is a protection transmission line, 23-3 is an interlaced transmission line, 24 is a return circuit, 25, 26 is a switching circuit, and 27 is a branch section.

The transmitting/receiving section 22-1 transmits and receives data to and from the active transmission line 23-1, and the transmitting/receiving section 22-2 transmits and receives data to and from the protection transmission line 23-2 or the skip transmission line 23 via the switching circuit 26. -3 is received and transmitted to the protection transmission line 23-2. Further, the branching section 27 branches the data from the protection transmission line 23-2 to the switching circuit 26 and the skip transmission line 23-3.

FIG. 8 is an explanatory diagram of a network according to another embodiment of the present invention, in which the monitoring node 30 and the nodes 40-1 to 40-5 are connected in a loop through the active transmission line 23-1, and the protection system transmission An interlaced transmission line 23-3 and a node are connected to the line 23-2 via a branch 27, and the protection transmission line 23-2 is shared as a part of the interlaced transmission line.

If each part is normal, a loop path using the active transmission line 23-1 is formed and data transmission is performed. Then, when the monitoring node 30 cannot receive the signal that has gone around the working transmission line 23-1, it determines that a failure has occurred, and issues a switching command to each node 40-1 to 40-1 to switch to the protection transmission line 23-2.
Send to 0-5.

For example, the active transmission line 2 between nodes 40-3 and 40-4
3-1, in response to a switching command from the active system to the standby system, the switching circuit 25 in each node 40-1 to 40-5 is controlled to switch, and the transmitter/receiver 22-2 The received data is switched to be transferred to the transmission/reception processing control section 21. Therefore, data received via the backup transmission line 23-2 is applied from the branching section 27 to the transmitting/receiving section 22-2 via the switching circuit 26,
-2 is sent to the protection transmission line 23-2. That is, a loop path is formed by the backup transmission line 23-2.

In addition, in the case of a single node failure, for example, if a failure occurs in the node 40-3 in FIG. A switching command for switching is sent from the monitoring node 30. Even when switching to the backup transmission line 23-2, the node 40
Since node 40-3 does not send data, node 40-2 cannot receive data via protection transmission line 23-2. When this state is identified by the transmission/reception processing control unit 21, the switching circuit 26 is controlled to switch from the branching unit 27 to the skip transmission line 23-3. Thereby, node 4
0-4 to the backup transmission line 23-2, branching section 27
The data via the skip transmission path 23-3 can be received via the jump transmission path 23-3, and a loop path shown by the thick line is formed to continue data transmission.

In the case of a double node failure, for example, if a failure occurs in nodes 40-2 and 40-4 in FIG.
-5 is from the working transmission line 23-1 to the protection transmission line 23-2
However, since node 4 (1-3, 40-1 cannot receive data via the switched protection transmission line 23-2), it switches to receive data via the skip transmission line 23-3 (■ 6). .Thereby, node 4(]-3,40-1
can receive data via the interlaced transmission path 23-3, so a loop path shown by the thick line is formed and data transmission is continued.

Furthermore, if a failure occurs in an adjacent node, for example, if a failure occurs in nodes 40-3 and 40-4 in FIG. The node 40-2 and 40-1 switch to the interlaced transmission line 23-3, however, since a loop route is not formed. Even with this, the signal cannot be received, so the monitor 30 sends a command to switch back to the working transmission line 23-1, and then sends a command to form a return route. As a result, the failed node 40-3.
A return circuit 24 is controlled at a node 40-2 and 40-5 adjacent to 40-4, and a return route is formed by this return circuit 24, the working transmission line 23-1, and the protection transmission line 23-2. is formed and data transmission continues.

Therefore, even if there are failures in multiple locations on the transmission path or failures in multiple nodes, it is possible to continue data transmission through healthy transmission paths and nodes.

The present invention is not limited to the embodiments described above; for example, the number of nodes can be increased or decreased. Also, the folding circuit 4, 14.24,
It is also possible to adopt a configuration in which part of the switching circuits 5, 15 and 25° 26 are shared.

〔Effect of the invention〕

As explained above, the present invention provides a method for skipping nodes using the skip transmission path 3-3 in a loop network that is made up of a double loop formed by the working transmission path 3-1 and the protection transmission path 3-2. A loop type network is constructed by connecting to the monitoring node 1, and the monitoring node 1 monitors for the occurrence of a failure by circulating signals, and when a failure is detected, it controls each node 2-1 to 2-n. , control for switching from the active system to the backup system by the switching circuit 5, or forming a return route by the return circuit 4, and switching to the skip transmission line 3-3 when data is not being transmitted via the protection system transmission line 3-2. By doing this, even if there are failures in multiple locations on the transmission line,
Also, if multiple nodes fail, the skipped transmission line 3-
3, it is possible to transmit data by skipping the faulty point, or to form a loopback route to separate the faulty point, which eliminates system downtime and improves the reliability of the loop network. There are advantages that can be achieved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the principle of the present invention, FIG. 2 is a block diagram of main parts of a node according to an embodiment of the present invention, FIG. 3 is an explanatory diagram of a network according to an embodiment of the present invention, and FIG. 4 is a node diagram. FIG. 5 is an explanatory diagram when a node has double failure. FIG. 6 is an explanatory diagram when forming a return route. FIG. 7 is a main block diagram of a node according to another embodiment of the present invention. 8 is an explanatory diagram of a network according to another embodiment of the present invention, FIG. 9 is an explanatory diagram at the time of one node failure, FIG. 10 is an explanatory diagram at the time of node double failure, and FIG. FIG. 12 is an explanatory diagram of a conventional network, and FIG. 13 is an explanatory diagram of a conventional network when two node failures occur. 1 is a monitoring node, 2-1 to 2-n are nodes, 3-1 is a working transmission line, 3-2 is a protection transmission line, 3-3 is a skip transmission line, 4 is a return circuit, and 5 is a switching circuit. It is.

Claims (1)

[Claims] A monitoring node (1) and a plurality of nodes (2-1 to 2-n)
The working and standby transmission lines are connected in a loop (3
-1, 3-2) and a skip transmission path (3-3) for performing data transmission by skipping adjacent nodes, and the nodes (2-1 to 2-n) are connected to the working transmission path. (
a loopback circuit (4) that loops back the data transmitted through 3-1) and sends it out to the protection transmission line (3-2); and a switching circuit (5) that switches to transmitting and receiving data via the skip transmission line (3-3). and when a failure occurs, the monitoring node (1)
The loop circuit (4) or the switching circuit (5) is controlled to continue data transmission so that a loop route or a loop route is formed from a node through a healthy node and a transmission path. Control method for loop network.