JP2001326620A - Standby path access method and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a standby path access method and system that can effectively utilize channels, provided with an active path and a standby path. SOLUTION: On the occurrence of a channel fault in an active path selected by a receiver side of an end node of a path protection switch ring system, a standby path having no fault is switched to relieve the channel in the standby path access method. When no channel fault exists in both the paths on the receiver side, a path which is not used for the active path is connected to the standby path and they are used as separate path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a standby path access method and apparatus, and more particularly to SONET (s).
ynchronous optical network
k) or SDH (synchronous digit)
The present invention relates to a standby path access method and apparatus in a path protection switching ring system of tal hierarchy.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional path protection switching ring system, wherein FIG.
(B) is an explanatory diagram at the time of a path failure. As shown in FIG. 5, in the path protection switch ring system,
On the transmitting side of the terminal node, EAST is performed for each path.
Bridge output is performed in the (E) direction and the WEST (W) direction. On the other hand, on the receiving side of the terminal node, E
The state of the line received from the AST (E) side and the WEST (W) side is monitored (see (a)).

[0003] EAST side, WES selected on the receiving side
When a line failure has occurred in any of the working paths 1 on the T side, switching to the backup path 2 having no failure has been performed to perform line rescue.

[0004]

However, in order to switch to the protection path 2, it is necessary to always have the protection path 2 together with the working path 1. However, this protection path 2 is normally used when both systems are normal. Was not used effectively.

That is, in the conventional path protection ring system, since the transmission side is a bridge output, if the line quality of both systems is good, the provided line has not been effectively utilized.

An object of the present invention is to provide a standby path access method and apparatus capable of effectively utilizing a line having a working path and a protection path.

[0007]

In order to achieve the above object, a standby path access method according to the present invention is characterized in that a line failure occurs in a working path selected on a receiving side of a terminal node of a path protection switching ring system. In the case, in the standby path access method of switching to a backup path without failure and performing line recovery, if there is no circuit failure of both paths on the receiving side, connect a path not used as the working path to the backup path, It is characterized by being used as separate paths.

With the above configuration, if a line failure occurs in the working path selected on the receiving side of the terminal node of the path protection switching ring system, the standby path switches to a protection path free from failure and performs line relief. In the access method, when there is no line failure in both paths on the receiving side, a path not used as the working path is connected to the backup path and used as a separate path. As a result, it is possible to effectively utilize a line having a working path and a protection path.

Further, the standby path access method according to the present invention can realize the above standby path access method.

[0010]

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

FIG. 1 shows a standby path access method (part 1) according to an embodiment of the present invention. FIG. 1 (a) is an explanatory diagram at a normal time, and FIG. 1 (b) is an explanatory diagram at a path failure.
2A and 2B show a standby path access method (part 2) according to an embodiment of the present invention, wherein FIG. 2A is an explanatory diagram at a normal time, and FIG. 2B is an explanatory diagram at a time of a path failure.

As shown in FIG. 1, in the path protection ring system 10, during normal operation, a working path 11 and a protection path 12 are separately set on the EAST (E) side and the WEST (W) side. (See (a)), backup path 1
2 can be used effectively. If a line failure occurs on the working path 11, the protection path 12 is changed to the working path 11.
(See (b)), and the line of the working path 11 is relieved.

As shown in FIG. 2, in the path protection ring system 10, the backup paths 12a, 12b, and 12c in the normal operation include not only the same terminal node as the working path 11 but also an intermediate node or an intermediate node between the intermediate nodes. However, the lines are separately set (see (a)), and the backup path 12 can be used effectively. The line rescue when a line failure occurs on the working path 11 is the same as in FIG. 1 (see (b)).

FIG. 3 is a block diagram showing a configuration of a terminal node in the path protection ring system of FIGS. As shown in FIG.
The WEST-side transmission selector 13 and the EAST-side transmission selector 14 for separately transmitting the working path 11 and the protection path 12 to the (E) side and the WEST (W) side face the line fault information detected on the receiving side. OH for sending to the side
(Over head) Insertion units 15 and 16 and a transmission control unit 17 that controls these units are provided.

On the receiving side, the EAST (E) side, the WEST
Reception monitor 1 that monitors faults on the (W) side path
8 and 19, a path switching control unit 20 for controlling path switching based on the result of the line failure, and reception selectors 21 and 22 for selecting a receiving-side path as an output for each of the active and standby paths.

FIG. 4 is a block diagram showing a configuration of an intermediate node in the path protection ring system of FIGS. As shown in FIG. 4, in order to use the backup path 12 at the intermediate node to perform transmission and termination of another line,
The transmission side of the intermediate node includes a reception monitor 23 that monitors a line failure of the protection path input (IN) signal, an OH insertion unit 24 that inserts the result into the OH, and an intermediate node ADM (Add-
And a main signal selector 25 for switching use / non-use of a Drop Multiplexer function.

In order to terminate a path at an intermediate node,
The receiving side of the intermediate node transmits the OH signal detected by the OH terminating unit 26 again to the OH terminating unit 26 for terminating the OH signal inserted on the transmitting side, the reception monitor 27 for detecting a line failure occurring in the intermediate node. OH insertion unit 28 to be inserted, and fault insertion unit 2 to insert a fault as a result of detection by the reception monitor 27
9 and a main signal selector 30 for switching use / non-use of the intermediate node ADM function.

That is, when there is no line failure of both paths on the receiving side, the standby path access device provided with the line setting means having the terminal node (see FIG. 3) and the intermediate node (see FIG. 4) sets the working path as the working path. If an unused path is set as a protection path line and a line failure occurs on the working path selected on the receiving side of the terminal node of the path protection switching ring system, it is switched to a failure-free backup path to rescue the line. It can be performed.

Next, operation of the standby path access device in the above-described path protection ring system will be described. 1. Operation of Terminal Node (See FIG. 3) In the standby path access method, when the working path 11 does not detect a failure in both systems on the receiving side, another line is set to the protection path 12. The receiving side monitors line faults on the reception monitors 18 and 19 from both the WEST and EAST paths, and outputs the result to the path switching control unit 20. Further, the reception monitors 18 and 19 transmit the OH transmitted from the opposite terminal node.
It monitors the information and outputs to the path switching control unit 20 whether or not a line failure has occurred on the working side of the opposing node.

The path switching control unit 20 determines from the above information
It is determined whether there is a failure in the working path 11 and whether there is a switching process. The result is output to the reception selectors 21 and 22 as a path switching command a.

The reception selectors 21 and 22 output a main signal to the working path DROP and the protection path DROP according to the path switching command a. When the working path 11 uses the protection path route, it outputs a line unavailable signal to the protection path DROP.

Further, the path switching control unit 20 transmits the switching information to the transmission-side control unit 17 in order to notify the opposite end node of the switching information.
To output a transmission unit control request command b. The transmission side control unit 17 sends the OH insertion units 15 and 16 according to the command b.
Inserts the path switching control information into the OH.

In addition, the reception monitors 18 and 19 collect the opposite-side path failure information from the opposite-side end nodes and output the information to the path switching control unit 20. The path switching control unit 20 determines whether switching is possible according to the opposite-side information. If switching is necessary due to a failure in the working path of the opposite node, a path switching command a is output, and the reception selectors 21 and 22 perform path switching.

The path switching controller 20 outputs a transmission control request command b to the transmission controller 17 in order to output a path switching request to the transmission selectors 13 and 14.
The transmission-side control unit 17 outputs a path switching command c to the transmission-side selectors 13 and 14 according to the command b. According to the path switching command c, the transmission selectors 13 and 14
The active path IN signal is bridged or switched to the protection path 12.

When the failure has been recovered from the working path 11, the above processing is performed in reverse, and another line is set to the protection path 12. 2. Operation of Intermediate Node (See FIG. 4) The intermediate node on the backup path 12 side is used in a through-line, as used in the operation of the above-mentioned terminal node, and is connected to another line using the backup path 12 between the intermediate nodes. May be terminated. In the case of through, the selector 25 and the selector 30 are set to the through side.

Backup path 1 between intermediate nodes and intermediate nodes
When terminating another line by using the communication path 2, the transmission side of the intermediate node checks the line failure of the protection path IN signal for the reception monitor 23.
To monitor. The fault result is inserted as OH into the OH of the intermediate path IN signal as fault information.

In addition, the reception monitor 23 passes through the OH insertion unit 24 to pass through the OH for monitoring the backup path (transmission and reception is information monitored by the OH insertion units 15 and 16 and the reception monitors 18 and 19). Insert afterwards,
The signal is output to the intermediate path OUT via the selector 25.

In order to terminate a path at an intermediate node,
Terminate the OH signal inserted at the intermediate node transmitting side, O
H termination (failure information detected on the protection path IN and working path information) is performed and deleted from the signal. The terminated working path information is reinserted by the OH insertion unit 28.

The reception monitor 27 monitors fault information detected on the backup path IN, and detects path fault information on the intermediate path IN. If there is fault information, the monitoring result is inserted as fault information by the fault insertion unit 29.

In addition, since the main signal is terminated at the intermediate path, the selector 29 switches to output an unused signal to the backup path OUT. Further, when the active node switching request information is detected by the reception monitor 23 or the OH termination unit 26, the intermediate node releases the termination at the intermediate node and switches the selectors 25 and 30 to the through setting.

Therefore, in the path protection switching ring system, if no line failure occurs in both the working path 11 and the protection path 12, the protection path 12
(See FIG. 1A) or the backup paths 12a and 12
b, 12c (see FIG. 2 (a)), another line can be set, and termination can be performed separately.

As a result, the working path 11 and the protection path 11
Since both paths can be used effectively, it is possible to accommodate traffic of a specified capacity or more.

That is, in the conventional path protection switching ring system, the transmitting side path is bridge-output to the WEST / EAST line, and the receiving side selects and terminates a path having good line quality. If there is no line failure in both paths on the receiving side, a path not used as the working path 11 is connected to the backup path 12 and used as a separate path, so that the number of usable lines can be increased.

As another embodiment, a backup path 12 having a lower priority order with respect to an active path 11 having a higher priority order is provided.
By assigning a priority within the protection path 12 and performing routing of the protection path 12 in addition to the two types of priority, the concept of the effective circuit path quality can be introduced.

As described above, according to the present invention, SONE
When relieving a line in a T or SDH path protection switch ring system, the path on the protection path side can be used as a protection line or an inexpensive line.

That is, if no line failure occurs in both the working and protection paths in the ring system, the protection path 1
Another line can be set for 2 or 12a, 12b, and 12c, and termination can be performed separately. Therefore,
Since each of the backup paths can be used effectively, it is possible to accommodate traffic of a prescribed capacity or more.

[0037]

As described above, according to the present invention, if a line failure occurs in the working path selected on the receiving side of the terminal node of the path protection switching ring system, the path is switched to the protection path without failure. In the standby path access method in which the line is remedied, if there is no line failure of both paths on the receiving side, the path not used as the working path is connected to the protection path and used as a separate path. In addition, a line having a backup path can be effectively used.

Further, with the standby path access device according to the present invention, the above-mentioned standby path access method can be realized.

[Brief description of the drawings]

FIGS. 1A and 1B show a standby path access method and apparatus (part 1) according to an embodiment of the present invention, wherein FIG. 1A is an explanatory diagram at a normal time, and FIG. 1B is an explanatory diagram at a path failure.

FIGS. 2A and 2B show a standby path access method and apparatus (part 2) according to an embodiment of the present invention, wherein FIG. 2A is an explanatory diagram at a normal time and FIG.

FIG. 3 is a block diagram showing a configuration of a terminal node in the path protection ring system of FIGS. 1 and 2;

FIG. 4 is a block diagram showing a configuration of an intermediate node in the path protection ring system of FIGS. 1 and 2;

5A and 5B show a conventional path protection switching ring system, wherein FIG. 5A is an explanatory diagram at a normal time, and FIG. 5B is an explanatory diagram at a time of a path failure.

[Explanation of symbols]

 Reference Signs List 10 path protection ring system 11 working path 12, 12a, 12b, 12c backup path 13 west side transmission selector 14 east side transmission selector 15, 16, 24, 28 OH insertion unit 17 transmission control unit 18, 19, 23, 27 reception monitor Reference Signs List 20 path switching control unit 21, 22 reception selector 25, 30 main signal selector 26 OH termination unit 29 fault insertion unit a, c path switching command b transmission unit control request command

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 5K028 AA06 CC02 CC06 DD05 DD06 KK01 MM05 MM14 PP04 PP22 QQ01 5K031 AA02 AA06 AA08 BA03 CA08 CB01 CB12 DA12 EA01 EA12 EB02 EB05 5K035 AA03 AA01 BB03 DD02

Claims (8)

[Claims] In a standby path access method, when a line failure occurs in a working path selected on a receiving side of a terminal node of a path protection switching ring system, the path is switched to a protection path having no failure to rescue the line. A path that is not used as the working path is connected to the backup path and used as a separate path when there is no line failure in both paths on the side. 2. The standby path access method according to claim 1, wherein the protection path has a lower priority than the working path having a higher priority. 3. The method according to claim 2, wherein the priority is assigned in the backup path by routing.
2. The standby path access method described in 1. 4. The path protection switch ring system according to claim 1, wherein said path protection switch ring system is a SONET (synchronous op).
physical network) or SDH (sync)
chronous digital hierarchy
4. The standby path access method according to claim 1, wherein the standby path access method is applied to y). 5. A standby path access apparatus for switching a working path selected on a receiving side of a terminal node of a path protection switching ring system on a receiving side and performing a line rescue by switching to a protection path having no failure. A standby path access device comprising: a line setting unit configured to set a path not used as the working path as a line of the backup path when there is no line failure of both paths on the side. 6. The standby path access device according to claim 5, wherein the protection path has a lower priority than the working path having a higher priority. 7. The line setting means includes: a transmission selector for transmitting a working path and a protection path on a transmission side; and an OH (over head) insertion for transmitting line failure information detected on a reception side to an opposite side. A transmission control unit that controls these units, a reception monitor that monitors a path failure on the receiving side, a path switching control unit that controls path switching based on a line failure result,
7. The standby path access device according to claim 5, further comprising a termination node comprising: a receiving selector for selecting a receiving-side path as a working / standby output. 8. A transmission monitor comprising: a reception monitor for monitoring a line failure of a protection path input (IN) signal; an OH insertion unit for insertion into an OH;
And an intermediate node ADM (Add-Drop Multi)
plexer) function, a main signal selector for switching use / non-use of the function, and an OH for terminating an OH signal inserted on the transmission side on the reception side.
Termination unit, reception monitor for detecting a line failure occurring in the intermediate node, OH insertion unit for reinserting an OH signal detected in the OH termination unit, failure insertion unit for inserting a failure detected as a result of detection in the reception monitor, and intermediate node ADM 8. The standby path access device according to claim 5, further comprising an intermediate node including a main signal selector for switching use / non-use of a function.