JPH04322537A - Ring communication network - Google Patents

Abstract

PURPOSE:To improve reliability by continuing the transmission service even when a fault takes place to a part of the ring communication network and not generating momentary interruption to the transmission service independently of a fault location. CONSTITUTION:A time slot selection section 10 always inserts a PCM primary group signal to both links, selects one predetermined link in the unit of channels and the signal is branched to the link. Fault detection sections 11,12 detect a fault of an inputted PCM primary group signal, output a counter station alarm to the other link or detects the counter station alarm from a counter station equipment of the other link and signal bit operation sections 8,9 operate a signal bit not used in the unit of channels to notify fault information. Signal bit monitor sections 6,7 monitor fault information of a counter station equipment and a time slot selection section 10 selects the other link with respect to the one link based on the fault information.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention is applied to a protection system for a ring-shaped communication network. In particular, two PCM primary group signals A and B
A ring-shaped circuit consisting of a plurality of nodes each having a digital add/drop device that adds/drops the time slots inside as another PCM primary group signal C, and two clockwise and counterclockwise links connecting the plurality of nodes. The present invention relates to a protection method for continuing transmission service by using the other link when a PCM primary group signal failure occurs in one link between certain nodes in a communication network.

0002

2. Description of the Related Art FIG. 3 is a block diagram of a conventional ring-shaped communication network. FIG. 4 is a diagram showing processing when a failure occurs in a conventional ring-shaped communication network.

Conventionally, in a ring-shaped communication network, when a transmission service is provided between nodes 2 and 4 as shown in FIG. 3, normally only one of the clockwise or counterclockwise transmission paths is provided. was used, and the other transmission path was reserved for detouring the failed link. PCM1 between node 1 and node 5
When a next group failure occurs, as shown in Figure 4, the PCM primary group signal is looped back by the digital add/drop multiplexer at both ends of the failed link, and the link in the opposite direction is used to bypass the failed link. Transmission services between Node 2 and Node 4 continued.

0004

[Problem to be Solved by the Invention] However, in such a conventional ring-shaped communication network, the EAST-WEST route and the WEST-EAST route are separate, and it is difficult to determine where in the ring-shaped communication network a failure occurs. However, EAST-WE
There was a drawback that momentary signal interruptions occurred on either the ST or WEST-EAST routes.

[0005] To explain with reference to FIG. 4, in the case of a failure between node 1 and node 5, there will be a momentary data interruption even for the transmission service between node 2 and node 4, which seems to be unrelated to the failure. There were some drawbacks that were bound to occur.

[0006] The present invention solves the above-mentioned drawbacks, and even if a failure occurs in a part of the ring-shaped communication network, it is possible to continue the transmission service at that part, and to provide transmission services unrelated to the failure part. The purpose of this is to provide a highly reliable ring-shaped communication network that does not cause momentary interruptions.

[0007]

[Means for Solving the Problems] The present invention includes a plurality of nodes connected in a ring shape via two counterclockwise and clockwise links, each of which has a plurality of digital signals being transmitted. In a ring-shaped communication network including a digital add/drop multiplexer that adds/drops one digital signal to a time slot, each digital add/drop multiplexer adds/drops the digital signal to the two links, respectively. A selection means for selecting and branching one of the links predetermined for each channel by inserting both, a means for detecting that a failure has occurred in the input digital signal and outputting a match alarm to the other link, and a means for outputting a match alarm to the other link. a detection means including a means for detecting a game warning from the device; and an operation means for notifying failure information by manipulating unused signal bits of a time slot on a channel-by-channel basis based on the detection information of the detection means of the own device;
monitoring means for monitoring failure information of the operating means of the game device, and the selection means includes means for selecting and branching one link to the other based on the monitoring information of the monitoring means of the own device. do

Further, the present invention provides that the digital signal is P
It can be a CM primary group signal.

[0009]

[Operation] Each digital add/drop device is provided with a selection means, a detection means, an operation means, and a monitoring means for each of the two links. The selection means normally inserts the digital signal into both the two links, selects one link predetermined for each channel, and branches the signal. The detection means detects that a failure has occurred in the input digital signal, outputs a game warning to other links, and also detects a game warning from a game device of the other link. The operating means operates the unused signal bits of the time slot on a channel-by-channel basis based on the detection information of the detecting means of its own device, and notifies the failure information. The monitoring means monitors failure information of the operating means of the game device. The selection means selects the other link to the one above based on the monitoring information of the monitoring means of its own device and branches.

[0010] As described above, even if a failure occurs in a part of the ring-shaped communication network, the transmission service at that part can be continued, and transmission services unrelated to the failure part can be reliable without causing momentary interruptions. You can improve your sexuality.

[0011]

Embodiments Examples of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a ring-shaped communication network according to an embodiment of the present invention.

In FIG. 1, the ring-shaped communication network includes a plurality of nodes 1 to 5 connected in a ring shape via two counterclockwise and clockwise links, and each node 1 to 5 has a plurality of nodes in transmission. It includes digital drop/drop/add devices 201 to 205 for adding/dropping the PCM primary group signal as one digital signal to an empty time slot of the PCM primary group signal as a digital signal.

The feature of the present invention is that each digital add/drop multiplexer 20 inserts a PCM primary group signal into each of the two links, and performs a predetermined signal on a channel-by-channel basis. time slot selection units 101 to 105 as selection means for selecting one link and branching; A failure detection unit 1 is used as a detection means including a means for detecting a game alarm from a game device.
11 to 115, 121 to 125, and signaling bit manipulation as an operation means for notifying failure information by manipulating unused signal bits of time slots in channel units based on detection information of failure detection units 11 and 12 of the own device. 81 to 85, 91 to 95, and signaling bit monitoring units 61 to 61 as monitoring means for monitoring failure information of the signaling bit operating units 8 and 9 of the game device.
65, 71 to 75, and the time slot selection unit 10 includes means for selecting and branching one link to the other based on monitoring information from the signaling bit monitoring units 6 and 7 of the own device.

[0014] The operation of the ring-shaped communication network having such a configuration will be explained. FIG. 2 is a diagram showing processing when a failure occurs in the ring-shaped communication network of the present invention.

In FIG. 1, transmission data 15 input to node 2 is inserted into the time slots of both clockwise and counterclockwise PCM primary group signals, and the time slot selection unit 104 of node 4 selects which one. It is branched from one of the PCM primary group signals and output from node 4. Conversely, transmission data 16 input to node 4 is output from node 2 in exactly the same manner. If both counterclockwise and clockwise rotations are normal, if you decide in advance which one to select, the transmission data will be EAST-WEST.
, WEST-EAST will pass through the same route.

Next, the situation when a failure occurs will be explained. Figure 2
indicates a case where a failure occurs between node 1 and node 5. The failure detection unit 115 of the node 5 detects that a failure has occurred in the PCM primary group signal between the node 1 and the node 5, and the signaling bit manipulation unit 95 detects that a failure has occurred in the PCM primary group signal between the node 1 and the node 5, and the signaling bit operation unit 95 detects the occurrence of a failure in the PCM primary group signal between the node 1 and the node 5. Fault information 13 is notified to node 4 using unused bits. At this time, since the signaling bit manipulation is performed on a channel-by-channel basis, the signal does not pass between node 1 and node 5. For example, nothing is done to the transmission channel between node 4 and node 5.

Signaling bit monitoring section 74 of node 4
detects that a failure has occurred in the transmission channel passing between node 1 and node 5, and the time slot selection unit 104 selects the PCM primary group signal on the normal side, that is, the PCM primary group signal via node 3. The time slot selection is changed so that the transmission data 15 is branched from. node 1
No changes occur for transmission channels that do not pass between and node 5, for example between node 4 and node 5.

The same holds true in the opposite direction. The fault detection unit 115 of the node 5 detects that a fault has occurred in the PCM primary group signal between the node 1 and the node 5, and sends a game warning 14 to the node 1. The failure detection unit 121 of node 1 detects the PCM1 between node 1 and node 5 by this game alarm 14.
Knowing that a failure has occurred in the next group signal, the signaling bit manipulation unit 81 manipulates the signaling bits for each channel to notify the node 2 of the failure occurrence.

Signaling bit monitoring unit 62 of node 2
detects that a failure has occurred in the transmission channel passing between node 1 and node 5, and the time slot selection unit 102 selects the PCM primary group signal on the normal side, that is, the PCM primary group signal via node 3. The time slot selection is changed so that the transmission data 16 is branched from. node 1
- no changes occur for transmission channels that do not pass between nodes 5, for example between nodes 2 and 3;

[0020]

[Effects of the Invention] As explained above, even if a failure occurs in a part of a ring-shaped communication network, the present invention can continue the transmission service at that part, and can provide transmission services unrelated to the failure part. has the excellent effect of improving reliability without causing momentary interruptions.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a ring-shaped communication network according to an embodiment of the present invention.

FIG. 2 is a diagram showing processing when a failure occurs in the ring-shaped communication network of the present invention.

FIG. 3 is a block diagram of a conventional ring-shaped communication network.

FIG. 4 is a diagram showing processing when a failure occurs in a conventional ring-shaped communication network.

[Explanation of symbols]

1 to 5 Nodes 61 to 65, 71 to 75 Signaling bit monitoring units 81 to 85, 91 to 95 Signaling bit operation units 101 to 105 Time slot selection units 111 to 115, 121 to 125
Fault detection unit 13 Fault information 14 Game warning 15 Transmission data (EAST-WEST, from node 2 to node 4) 16 Transmission data (WEST-EAST, from node 4 to node 2)

Claims (2)

[Claims] Claim 1: A plurality of nodes connected in a ring through two counterclockwise and clockwise links, each of which transmits one digital signal in an empty time slot of the plurality of digital signals being transmitted. In a ring-shaped communication network including a digital add/drop multiplexer that adds/drops the digital signal, each of the digital add/drop multiplexers inserts the digital signal into the two links, respectively, and performs a predetermined signal on a channel-by-channel basis. selecting means for selecting and branching one of the linked links; means for detecting that a failure has occurred in the input digital signal and outputting a game warning to the other link; and detecting a game warning from the game device of the other link. a detection means including a detection means of the own device, an operation means for manipulating unused signal bits of a time slot for each channel based on detection information of the detection means of the own device to notify failure information, and failure information of the operation means of the opponent device. a ring-shaped communication network, wherein said selection means includes means for selecting and branching said one link to said other link based on monitoring information of said monitoring means of said device. 2. The ring-shaped communication network according to claim 1, wherein said digital signal is a PCM primary group signal.