JPH06164615A - Double ring transmission line communication system - Google Patents

Abstract

PURPOSE:To attain the effective operation of the network resources in the N:M type communication by providing a working path on one of both transmission lines with a stand-by path provided on the other transmission line and adding a transmission line restoring means to each node, thereby reducing the switching frequency of path identification numbers and economizing the transmission capacity. CONSTITUTION:The double ring transmission lines 50 and 60 are connected to the nodes 1-6 and transmit the information to the paths shown by the path identification numbers. The transmission and reception nodes are included in the nodes 1, 3 and 5. The counterclockwise line 50 includes a working path 10, and the clockwise line 60 includes a stand-by path 20 respectively. The path 10 joins an input path as all transmission nodes in the first round and then branches out at all nodes in the second round. Meanwhile the path 20 branches out at all reception nodes in the second round. Thus the number of nodes is decreased on both paths 10 and 20 when each node performs the loop- back restoration due to the detecting of the faults of the transmission lines.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a dual ring transmission line communication system by digital communication. The present invention relates to failure recovery of a ring transmission line such as packet communication and ATM (asynchronous transfer mode) communication. In particular, the present invention relates to a path restoration method by loopback of N: M type communication in which the number of transmitting nodes in the ring transmission path is N and the number of receiving nodes is M.

[0002]

2. Description of the Related Art Conventionally, a dual ring transmission line communication system uses N: 1 path restoration method in which the number of transmitting nodes in the ring transmission line is N and the number of receiving nodes is 1, and a plurality of N: By setting one path, or by setting a plurality of 1: N paths using a 1: N path restoration method in which the number of transmitting nodes in the ring transmission line is 1 and the number of receiving nodes is N Equivalently, N: M type communication was restored (Japanese Patent Application No. 4-1.
No. 14958, unpublished at the time of filing of the present application, see).

First, the N: 1 path restoration method in which the number of transmitting nodes in the ring transmission line is N and the number of receiving nodes is 1 will be described below.

FIG. 5 is a diagram showing a path setting for restoring N: 1 paths of the first conventional dual ring transmission line communication system, in which six nodes are connected by opposing dual ring transmission lines. The configuration is shown below. In FIG. 5, 50 is a counterclockwise ring transmission line, 60 is a clockwise ring transmission line, 1 to 6 are nodes, 51 is a working path, and 61 is a backup path. Here, the nodes 1, 3, and 5 are transmission nodes, and the node 1 is a reception node. Further, upstream and downstream are determined based on the transmission path of the working path 51.

The working path 51 is set so that the node 1 is the starting point, the nodes 3 and 5 join the paths from outside the ring transmission path, and the node 1 is the ending point.

The backup path 61 is set in a reverse transmission path, and the node 6 which is one upstream node of the node 1 at the end point of the working path 51 is used as a starting point, and the node 1 is connected to the end point of the working path 51.

FIG. 6 is a diagram showing a restoration process when a transmission line failure occurs in the N: 1 path of the first conventional dual ring transmission line communication system, and 100 indicates a transmission line failure point. The path is restored by connecting the working path 51 to the backup path 61 after receiving the transmission path failure notification signal from the downstream node 5 at the node 4 upstream of the failure transmission path or after detecting the transmission path failure at the own node 4. By doing.

FIG. 7 is a diagram showing a path setting for restoring N: M paths equivalently by combining N: 1 paths in the second conventional dual ring transmission line communication system.
Reference numerals 3 and 5 are a transmitting node and a receiving node, and 55 is a distributing means. Further, 51 is a working path when the nodes 1, 3 and 5 are transmitting nodes and the node 1 is a receiving node, and 61 is a backup path of the working path 51. Furthermore, 5
Reference numeral 2 is a working path when the nodes 1, 3 and 5 are transmitting nodes and the node 3 is a receiving node, and 62 is a backup path of the working path 52. Also, 53 is the node 1, 3, 5
Is a transmitting node and node 5 is a receiving node, and 63 is a backup path of the working path 53.

As shown in FIG. 7, when N: M communication is restored equivalently using the N: 1 path restoration method, 18 path identification numbers (VPI, Virtual) are used as working paths.
Path Identifier) and a path identification number of 15 as a backup path. In addition, the transmission capacity is tripled because the input paths are branched into three.

Next, a 1: N path restoration method in which the number of transmitting nodes in the ring transmission line is 1 and the number of receiving nodes is N will be described.

FIG. 8 is a diagram showing the path setting when the 1: N path is restored in the third conventional dual ring transmission line communication system, in which six nodes are connected to each other by the opposing double ring transmission line. It is a configuration. Reference numeral 50 is a counterclockwise ring transmission line, 60 is a rightward ring transmission line, 1 to 6 are nodes, 71 is a working path, and 81 is a backup path.

Here, the node 1 is a transmitting node and the nodes 1, 3 and 5 are receiving nodes. The working path 71 is set so that the node 1 is the starting point, the nodes 3 and 5 branch off, and the node 1 is the ending point.

The backup path 81 is set in the reverse transmission path, and the node 6 which is one upstream node of the end point node of the working path 71 is set as a starting point, and the node 6 which is the most downstream receiving node of the working path 71 is set first. The receiving node branches at each receiving node, and is connected to the end point of the working path 71 at node 3, which is the most upstream receiving node of the working path 71.

FIG. 9 is a diagram showing a recovery process when a transmission line failure occurs in a 1: N path of the third conventional dual ring transmission line communication system, and 100 is a transmission line failure point.

To recover the path, the node 4 upstream of the failed transmission line receives the transmission line failure notification signal from the downstream node 5 or the local node 4 detects the transmission line failure, and the active path 71 is replaced by the backup path 81. By connecting to (upstream side if duplex is set).

FIG. 10 is a diagram showing a path setting for recovering an N: M path equivalently by combining 1: N paths in the fourth conventional dual ring transmission line communication system. In FIG. 10, reference numerals 1, 3, and 5 are transmitting nodes or receiving nodes, and 75 is a multiplexing means. 71 is the node 1
Is a transmitting node and nodes 1, 3 and 5 are receiving nodes, the working path and 81 are backup paths of the working path 71. 72 uses node 3 as a transmitting node, and node 1,
The working path and 82 when the nodes 3 and 5 are the receiving nodes are backup paths of the working path 72. Further, 73 is a working path when node 5 is a transmitting node and nodes 1, 3 and 5 are receiving nodes, and 83 is a backup path of the working path 73.

As shown in FIG. 10, when the N: M type communication is restored equivalently by using the 1: N path restoration method, 18 path identification numbers are required as the working path and the backup path is used. Requires a path identification number of 27. Also, since there are many paths, a large amount of transmission capacity is required.

[0018]

However, in such a conventional dual ring transmission line communication method, the N: 1 restoration method or the 1: N restoration method is equivalently used as N:
When recovering M-type communication, many path identification numbers are required, and a large transmission capacity is required, so that there is a problem that the network cannot be operated efficiently.

FIG. 11 is a block diagram of a cell of the dual ring transmission line communication system.

Here, when each node receives the cell shown in FIG. 11, it rewrites the path identification number to the path identification number of its own node and sends it to the next node. Processing becomes complicated and the processing load on the node increases. Also, since the number of path identification numbers to be assigned becomes large, the number of digits of the path identification number must be large. Each of these limits the transmission capacity.

The present invention solves the above problems,
An object of the present invention is to provide a dual ring transmission line communication method which can reduce the number of times of exchanging path identification numbers, make the transmission capacity economical, and efficiently operate network resources in N: M type communication on the dual ring transmission line. And

[0022]

SUMMARY OF THE INVENTION The present invention comprises a pair of opposing dual ring transmission lines to which a plurality of nodes are connected and which transmits information to a path indicated by a path identification number. In a dual ring transmission line communication system of an ATM network including a transmission node and a reception node, one transmission line of the double ring transmission line starts from a transmission node predetermined as a first transmission node in the first round. All the sending nodes join the input path, and on the second round, the working path is set so that all the receiving nodes branch from the receiving node of the node including this first sending node and end at the final receiving node. The other transmission path in the opposite direction to the one transmission path, starting from a node upstream from the final receiving node of the working path on the one transmission path, and in two rounds, A backup path that is set so that all receiving nodes branch from the last receiving node of the working path and end at the first receiving node of the working path, and each of the nodes has one on the one transmission path. It is characterized by including a recovery means for recovering the transmission path based on the failure detection result of the transmission path to the downstream node.

According to the present invention, each of the nodes is
The self-node can be configured to detect a failure of a transmission path between the node on the one side and a downstream node on the one transmission path, and provide the failure detection result to the restoration means.

Further, according to the present invention, each of the nodes detects a failure in a transmission path between the node and an upstream node on the one transmission path, and the detection result is used as a recovery means for the upstream node. Can be configured to notify.

Further, according to the present invention, in the case of a node including the working paths output by two of the nodes, the restoration means selects one of the two working paths output based on the failure detection result. The first round is branched and cell copied to be connected to each of the two backup paths, and the second round of the two output working paths is connected to the first round of the two backup paths. Can be configured as

Further, according to the present invention, in the case where the restoration means is a node including one working path output by one of the nodes and one protection path outputted by the node, one of the nodes is based on the failure detection result. Can be configured to connect the working path output by the above to this one backup path.

Further, according to the present invention, in the case of a node including the working path output by one of the nodes and the backup path output by two of the nodes, the restoration means is based on the failure detection result. Can be configured to connect the working path output by the first path of the two output backup paths.

[0028]

[Function] The working path merges with the input path at all transmitting nodes on the first round, branches at all receiving nodes on the second round, and the backup path branches at all receiving nodes on the second round, so each node transmits. When performing loopback recovery based on the result of path failure detection, the number of working paths and protection paths is reduced, the number of times the path ID numbers are replaced is reduced, and the ring transmission capacity is made more economical than the conventional technology to achieve double ring transmission. Network resources can be efficiently operated by N: M type communication on the road.

[0029]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a path setting for restoring an N: M path in which the number of transmitting nodes is N and the number of receiving nodes is M in the dual ring transmission line communication system according to an embodiment of the present invention. .

In FIG. 1, the dual ring transmission line communication system is a method in which a plurality of nodes 1 to 6 are connected and an opposing dual ring transmission line 5 for transmitting information to the path indicated by the path identification number.
0, 60, nodes 1 to 3 of nodes 1 to 6,
5 includes a transmitting node and a receiving node.

A feature of the present invention is that the counterclockwise ring transmission line 50 as one of the double ring transmission lines 50 and 60 is a transmission node which is predetermined as the first transmission node in the first round. The node is set as the starting point and all the sending nodes join the input path. On the second round, the receiving node of node 1 including this first sending node branches at all the receiving nodes and the final receiving node is set as the end point. The right-handed ring transmission line 60, which is the other transmission line in the opposite direction to the left-handed ring transmission line 50, is provided from the last receiving node of the working path 10 to the left-handed ring transmission line 50. In the above, the upstream node 4 is the starting point, and in the second round, all receiving nodes branch from the last receiving node of the working path 10 and the first receiving node of the working path 10 is the ending point. Comprising a backup path 20 that is set to,
Each of the nodes 1 to 6 is to include a restoration unit that restores the transmission path on the counterclockwise transmission path 50 on the basis of the failure detection result of the transmission path between the node and the downstream node.

Each of the nodes 1 to 6 detects a fault in the transmission line between the node 1 and the downstream node on the counterclockwise ring transmission line 50 at its own node and gives the fault detection result to the restoration means. Including means.

Further, each of the nodes 1 to 6 detects a failure of the transmission path to the upstream node on the left-hand ring transmission path 50, and the detection result is used as a recovery means for the upstream node. Including means to notify.

Further, in the case of the node including the working paths 10 output from two of the nodes 1 to 6, the restoration means outputs these two working paths 1 based on the failure detection result.
The first round of 0 is branched and cell copied to be connected to two backup paths 20, and the second round of the two output working paths 10 is connected to the two backup paths 20. Including means to connect to the first round.

Further, in the case of the node including the working path 10 that outputs one of the nodes 1 to 6 and the backup path 20 that outputs one of the nodes 1 to 6, the restoration means is based on the failure detection result. And a means for connecting the working path 10 output by the above to this one backup path 20.

Further, in the case of the node including the working path 10 that outputs one of the nodes 1 to 6 and the backup path 20 that outputs two of the nodes 1 to 6, the restoration means is based on the failure detection result. And a means for connecting the working path 10 output by the first path of the two output backup paths 20.

A dual ring transmission line communication system having such a configuration will be described.

FIG. 1 shows a configuration in which 6 nodes are connected by opposing double ring transmission lines, and 1 to 6 are nodes 1, 3,
5 is a transmitting node and a receiving node, 50 is a counterclockwise ring transmission line, 60 is a clockwise ring transmission line, 10 is a working path, and 20 is a backup path.

A method of setting a working path for N: M type communication will be described.

As shown in FIG. 1, a predetermined transmission node (node 1 in FIG. 1) is set as a starting point of the working path 10 on one side ring (ring transmission line 50), and the transmission paths are sequentially joined to the input paths. , After passing all the sending nodes,
Each receiving node branches and the final receiving node is the end point.

Next, a method of setting a backup path will be described.

As shown in FIG. 1, a backup path 60 is set on the opposing ring (ring transmission line 60) of the working path 10,
Starting from the node 4 one upstream of the end point of the working path 10,
After passing through the node 5 at the end of the working path, each receiving node is set to branch to the working path 10 and the final receiving node is set as the ending point.

Next, an example of transmission line failure recovery will be described.

FIG. 2 is a diagram showing a recovery process in the event of a transmission line failure when the working paths of the dual ring transmission line communication system of the present invention are set to be duplicated.

As shown in FIG. 2, in the node 5 upstream of the failed transmission line, after receiving the transmission line failure notification signal from the downstream node 5 or after detecting the transmission line failure in the own node, the active node of the first round is used. After the path 10 is cell copied and branched, the path 10 is connected to both of the two backup paths 20 on the ring transmission line to distribute the cells.

On the other hand, the working path 10 of the second round is connected to the backup path 20 of the first round on the opposite transmission path. By performing the above-mentioned path connection, N:
The M-type communication can be restored.

FIG. 3 is a diagram showing a recovery process at the time of transmission line failure when only one working path is set in the dual ring transmission line communication system of the present invention and only one backup path is provided on the opposite transmission line. .

As shown in FIG. 3, the node 6 upstream of the failed transmission line receives the transmission line failure notification signal from the downstream node 1 or, after detecting a transmission line failure at its own node, the working path 10 Is connected to a backup path on the opposite transmission path. By performing the above-mentioned path connection, N: M type communication can be performed at the time of transmission line failure as in the above case.

FIG. 4 is a diagram showing a recovery process at the time of transmission line failure when only one working path is set in the dual ring transmission line communication method of the present invention and two backup paths are provided on the opposite transmission line.

FIG. 4 shows the case where the node 6 is the receiving node and the node 7 is newly provided. Since the final transmitting node is the node 5, the node 6 becomes the first receiving node,
Between node 6 and node 1, there is one working path and two protection paths. As shown in FIG. 4, in the upstream node 7 of the failed transmission path, after receiving the transmission path failure notification signal from the downstream node 1 or after detecting the transmission path failure in the own node, the working path is set on the opposite transmission path. Connect to a certain first round backup path (when there are two backup paths). By performing the path connection described above, it is possible to recover N: M type communication in the same manner when a transmission line fails.

As described above, in this embodiment, the number of path identification numbers of the working path is 10 and the number of backup path identification numbers is 9.
In addition, since the input paths are joined by one working path, the transmission line capacity can be reduced.

[0052]

As described above, according to the present invention, the number of working paths and backup paths is reduced to reduce the number of times the path identification numbers are replaced at the time of restoration, and the time during which a cell stays at a node is shortened. Also, since the number of path identification numbers assigned can be reduced, the cells can be made smaller, and the number of working paths and backup paths can be reduced, so that the transmission capacity to be prepared can be made economical. Therefore, there is an excellent effect that network resources can be efficiently operated by N: M type communication on the dual ring transmission line.

[Brief description of drawings]

FIG. 1 is a diagram showing a path setting for restoring an N: M path in a dual ring transmission line communication system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a recovery process at the time of a transmission line failure when a dual working path is set in the dual ring transmission line communication method of the present invention.

FIG. 3 is a diagram showing a recovery process at the time of transmission line failure when only one working path is set in the dual ring transmission line communication method of the present invention and only one backup path is present on the opposite transmission line.

FIG. 4 is a diagram showing a recovery process in the event of a transmission line failure when only one working path is set in the dual ring transmission line communication method of the present invention and two backup paths are provided on the opposite transmission line.

FIG. 5 is a diagram showing a path setting for restoring the N: 1 path of the dual ring transmission line communication method of the first conventional example.

FIG. 6 is a diagram showing a restoration process when a transmission line failure occurs in an N: 1 path of the dual ring transmission line communication system of the first conventional example.

FIG. 7 is a diagram showing a path setting for recovering an N: M path equivalently by combining N: 1 paths in the second conventional dual ring transmission line communication system.

FIG. 8 is a diagram showing a path setting when a 1: N path is restored in the dual ring transmission line communication method of the third conventional example.

FIG. 9 is a diagram showing a recovery process when a transmission line failure occurs in a 1: N path of a third conventional dual ring transmission line communication system.

FIG. 10 is a diagram showing a path setting for recovering an N: M path equivalently by combining N: M paths of a dual ring transmission line communication system of a fourth conventional example.

FIG. 11 is a block diagram of a cell of a dual ring transmission line communication system.

[Explanation of symbols]

1 to 6 Nodes 10 1, 3, 5 as starting points and nodes 1, 3, 5 as end points N: M type communication working path 20 Working path 10 backup path 50 Counterclockwise ring transmission path 51, 52, 53 Nodes 1, 3 and 5 as starting points, node 1
N-1 type communication working path 55 distant means 60 clockwise ring transmission path 61 working path 51 backup path 62 working path 52 backup path 63 working path 53 backup path 71 node 1 starting point, node 1: N-type communication working path with 1, 3 and 5 as end points 72 Starting point with node 3, 1: N-type communication working path with nodes 1, 3, and 5 as end points 73 Starting point with node 5 and node 1, 1: N-type communication working path with 3 and 5 as end points 75 Multiplexing means 81 Backup path of working path 71 82 Backup path of working path 72 83 Backup path of working path 72 100 Transmission line failure point

Claims (6)

[Claims] 1. A dual ring transmission line is provided, which is connected to a plurality of nodes and transmits information to a path indicated by a path identification number. The plural nodes include a transmission node and a reception node. In an ATM network dual ring transmission line communication method, one transmission line of the dual ring transmission line is an input path at all transmission nodes starting from a transmission node predetermined as a first transmission node in the first round. Join up,
On the second lap, it is equipped with a working path that is set so that all receiving nodes branch off from the receiving nodes of the node including this first transmitting node, and the final receiving node is the end point. The other transmission line of the above, starting from a node one upstream on the one transmission line from the last receiving node of the working path, branches at all receiving nodes from the last receiving node of the working path in two rounds. A backup path is set so that the first receiving node of the working path is set as an end point, and each of the nodes is based on a failure detection result of a transmission path between the node and a downstream node on the one transmission path. A dual ring transmission line communication system including a recovery means for recovering the transmission line. 2. Each of the nodes includes means for detecting a failure of a transmission path between itself and one downstream node on the one transmission path, and providing the failure detection result to the recovery means. 1. The dual ring transmission line communication method described in 1. 3. Each of the nodes has means for detecting a failure in a transmission path between the upstream transmission node and the one upstream transmission path on the one transmission path, and notifying the detection result to the recovery means of the upstream node. The dual ring transmission line communication system according to claim 1, including the above. 4. The recovery means is configured to operate in two of the nodes.
In the case of a node including a working path output by a book, based on the failure detection result, the first round of the two working paths output is branched and cell copied and connected to the two backup paths respectively. 2. The dual ring transmission line communication system according to claim 1, further comprising means for connecting the second round of the two working paths output to the first round of the two backup paths. 5. The restoration means is one of the nodes.
In the case of a node including a working path output by a book and one protection path output by a book, a means for connecting the one working path output to the one protection path based on a failure detection result is included. 1. The dual ring transmission line communication method described in 1. 6. The restoration means is one of the nodes.
In the case of a node including a working path output by a book and two protection paths output by the book, the one working path output based on the failure detection result is used as the first round of the two protection paths output. The dual ring transmission line communication system according to claim 1, further comprising means for connecting.