JP3459896B2 - Standby path access device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 device in a path protection switch ring system of the T. Hierarchy).

[0002]

2. Description of the Related Art FIG. 5 shows a conventional path protection switching system, in which FIG.
(B) is an explanatory diagram of a path failure. As shown in FIG. 5, in the path protection switching system,
At the transmission side of the end 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)).

EAST side, WES selected by the receiving side
When a line failure occurs in either of the working paths 1 on the T side, the line is relieved by switching to the backup path 2 having no failure.

[0004]

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

That is, in the conventional path protection ring system, since the transmitting side has a bridge output, when 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 equipment can be effectively used a line having a working path and a protection path.

[0007]

To achieve the above object, in the standby path access device according to the present invention, a line failure occurs in the working path selected by the receiving side of the terminal node of the path protection switching system. In this case, in the standby path access device that switches to a protection path without failure and rescues the circuit, if there is no circuit failure of both paths on the receiving side, set the path not used as the working path to the protection path circuit. Line setting means
And the line setting means inputs the backup path to the transmitting side.
Reception monitor for monitoring line failure of (IN) signal and its connection
OH insertion part to be inserted into fruit OH and intermediate node ADM
(Add-Drop Multiplexer) function
Main signal selector that switches between used and unused and the receiving side
OH termination for terminating the OH signal inserted at the transmission side
Receivers that detect line failures that occur in
OH to re-insert the OH signal detected at the OH terminal
Failure to insert a failure as a result of detection by the insertion unit or reception monitor
Turns on / off the insertion part and the intermediate node ADM function
It is characterized in that chromatic intermediate node comprising a main signal selector changing Ri.

With the above configuration, when a line failure occurs in the working path selected on the receiving side of the terminal node of the path protection switching system, the standby path is switched to a protection-free path to rescue the line. The access device inputs the backup path (IN) to the transmitting side.
Reception monitor for monitoring signal line failure, resulting in OH
The OH insertion part to be inserted and the intermediate node ADM (Add-
Use / Unuse of the Drop Multiplexer function
The main signal selector that switches the
OH termination unit for terminating the inserted OH signal, intermediate node
Reception monitor and OH terminating unit for detecting line failures that occurred in
The OH insertion section that re-inserts the OH signal detected in
Failure insertion part that inserts a failure as a result of detection by Nita, and medium
Main signal for switching between use and non-use of inter-node ADM function
The line setting means for chromatic intermediate node comprising a selector
Therefore, if there is no line failure on both paths on the receiving side, set the path that is not used as the working path to the backup path line.
It As a result, the line having the working path and the protection path can be effectively used.

[0009]

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a standby path access method (No. 1) according to an embodiment of the present invention. (A) is an explanatory diagram for a normal time and (b) is an explanatory diagram for a path failure.
2A and 2B show a standby path access method (No. 2) according to an embodiment of the present invention. FIG. 2A is an explanatory diagram for a normal time and FIG. 2B is an explanatory diagram for a path failure.

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

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

FIG. 3 is a block diagram showing the configuration of a terminal node in the path protection ring system of FIGS. 1 and 2. As shown in FIG. 3, the transmitting side is
The line fault information detected on the receiving side is opposed to the west side transmitting selector 13 and the east side transmitting selector 14 for separately transmitting the working path 11 and the protection path 12 to the (E) side and the west (W) side, respectively. OH to send to the side
It has (over head) insertion units 15 and 16 and a transmission control unit 17 that controls them.

The receiving side is the EAST (E) side, and the WEST
Reception monitor 1 for monitoring faults on the (W) side
8 and 19, a path switching control unit 20 that controls path switching based on the line failure result, and reception selectors 21 and 22 that select a reception side path as an output of each of the working / standby.

FIG. 4 is a block diagram showing the configuration of an intermediate node in the path protection ring system of FIGS. As shown in FIG. 4, in order to perform transmission and termination of another line by using the protection path 12 at the intermediate node,
The transmission side of the intermediate node includes a reception monitor 23 that monitors the 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-
A main signal selector 25 that switches between use and non-use of the Drop Multiplexer function.

In order to terminate the path at the intermediate node,
The reception side of the intermediate node again receives the OH termination unit 26 that terminates the OH signal inserted at the transmission side, the reception monitor 27 that detects a line fault occurring at the intermediate node, and the OH signal detected by the OH termination unit 26. An OH insertion section 28 to be inserted and a failure insertion section 2 to insert a failure as a result of detection by the reception monitor 27.
9 and a main signal selector 30 that switches between use and non-use of the intermediate node ADM function.

That is, when there is no line failure of both paths on the receiving side by the standby path access device having the line setting means having the terminating node (see FIG. 3) and the intermediate node (see FIG. 4), it is determined as the working path. If an unused path is set as the protection path line and a line failure occurs in the working path selected by the receiving side of the terminal node of the path protection switching system, the protection path is switched to a protection path that does not have a failure. It can be performed.

Next, the operation of the standby path access device in the above 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 the line failure in the reception monitors 18 and 19 from both the WEST and EAST paths and outputs the result to the path switching control unit 20. In addition, the reception monitors 18 and 19 transmit the OH transmitted from the opposite end node.
The information is monitored and the presence / absence of a line failure on the working side of the opposite node is output to the path switching control unit 20.

From the above information, the path switching control unit 20
The presence / absence of a failure in the working path 11 and the presence / absence of switching processing are determined. The result is output as the path switching command a to the reception selectors 21 and 22.

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.

Also, the path switching control unit 20 sends the switching information to the opposite end node, so that the transmission side control unit 17 can notify the switching information.
The transmitter control request command b is output to. The transmitting-side control unit 17 follows the command b, and the OH insertion units 15 and 16
At, the path switching control information is inserted into OH.

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

The path switching control unit 20 also outputs a transmission unit control request command b to the transmission side control unit 17 in order to output a path switching request to the transmission side selectors 13 and 14.
The transmission side control unit 17 outputs the path switching command c to the transmission side selectors 13 and 14 in accordance with the command b. The transmission selectors 13 and 14 follow the path switching command c
The working path IN signal is bridged or switched to the protection path 12.

When the failure is restored in the working path 11, the reverse processing described above is performed to set another line in the protection path 12. 2. Operation of Intermediate Node (Refer to FIG. 4) The intermediate node on the side of the backup path 12 is used as a through node as in the operation of the above-mentioned end node, and when the backup path 12 is used between the intermediate nodes and another line is used. May be terminated. In the case of through, the selectors 25 and 30 are set to the through side.

Backup path 1 between intermediate nodes
2 is used to terminate another line, the transmission side of the intermediate node receives the line failure of the backup path IN signal by the reception monitor 23.
To monitor. The failure result is inserted as OH into the OH of the intermediate path IN signal as failure information.

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

In order to terminate the path at the intermediate node,
Terminating the OH signal inserted at the transmitting side of the intermediate node, O
H termination (fault information and working path information detected by the backup path IN) is performed and deleted from the signal. The terminated working path information is reinserted by the OH inserting unit 28.

Further, the reception monitor 27 may monitor the fault information detected by the backup path IN and may detect the fault information detected by the intermediate path IN. If there is failure information, this monitoring result is inserted as failure information by the failure insertion unit 29.

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

Therefore, in the path protection switching 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 system paths 12a, 12
b, 12c (see FIG. 2 (a)), another line can be set and terminated separately.

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

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

As another embodiment, a working path 11 having a high priority and a protection path 12 having a low priority are used.
However, not only the two types of priority orders but also the priority order is assigned in the protection path 12 and the protection path 12 is routed, so that the concept of effective line path quality can be introduced.

Thus, according to the present invention, SONE
When repairing a line in the T or SDH path protection switching system, the path on the protection path side can be used as a backup line or an inexpensive line.

In other words, if no line failure has occurred in both the working and protection paths in the ring system, protection path 1
2 or 12a, 12b, 12c can be set to different lines and terminated separately. Therefore, working /
Since each protection path can be effectively used, it is possible to accommodate more traffic than the specified capacity.

[0037]

As described above, according to the present invention, when a line failure occurs in the working path selected by the receiving side of the terminal node of the path protection switching system, the protection path is switched to a failure-free backup path. The standby path access device that rescues the circuit by
Reception monitor that monitors the line fault of the input signal (IN),
As a result, the OH insertion part to be inserted into the OH and the intermediate node A
DM (Add-Drop Multiplexer) function
Main signal selector that switches between used and unused and the receiving side
OH termination for terminating the OH signal inserted at the transmission side
Receivers that detect line failures that occur in
OH to re-insert the OH signal detected at the OH terminal
Failure to insert a failure as a result of detection by the insertion unit or reception monitor
Turns on / off the insertion part and the intermediate node ADM function
To have the intermediate node comprising a main signal selector changing Ri
By the line setting means, if there is no line failure of both paths on the receiving side, the path not used as the working path is the backup path
Since it is set to the line of No. 2, it is possible to effectively use the line having the working path and the protection path.

[0038]

[Brief description of drawings]

FIG. 1 shows a standby path access method and device (No. 1) according to an embodiment of the present invention, (a) is an explanatory diagram for a normal time, and (b) is an explanatory diagram for a path failure.

2A and 2B show a standby path access method and device (No. 2) according to an embodiment of the present invention, (a) is an explanatory diagram for a normal time, and (b) is an explanatory diagram for a path failure.

FIG. 3 is a block diagram showing a configuration of an end 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 system, in which FIG. 5A is an explanatory diagram for a normal state and FIG. 5B is an explanatory diagram for a path failure.

[Explanation of symbols]

10 pass 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 part 17 Transmission control unit 18, 19, 23, 27 Reception monitor 20-path switching control unit 21,22 Receive selector 25,30 Main signal selector 26 OH terminal 29 Obstacle insertion part a, c Path switching command b Transmitter control request command

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04J 3/00 H04L 12/437 H04L 29/14

Claims (3)

(57) [Claims] 1. When a line failure occurs in a working path selected by a receiving side of a terminal node of a path protection switching system, a standby path access device that switches to a protection-free path and rescues the line is received. If there is no line failure of both systems pass the side, have a line setting means for setting a path that is not used as the working path to the line of the backup path, the line setting means, the transmitting side, the backup path inputs Monitors line faults of (IN) signals
Reception monitor, and as a result, an OH insertion part to be inserted into the OH,
And an intermediate node ADM (Add-Drop Multi)
Main signal for switching between use and non-use of the (plexer) function
OH for terminating the OH signal inserted at the transmission side at the selector and the reception side
Reception that detects line faults that occur at the terminal and intermediate nodes
Reinsert the OH signal detected at the monitor and OH terminal
Insert a fault as a result of detection by the OH insertion unit and reception monitor
Use / not use of fault insertion part and ADM function of intermediate node
A standby path access device characterized by having an intermediate node consisting of a main signal selector for switching between . 2. The standby path access device according to claim 1 , wherein the protection path has a lower priority than the working path having a higher priority. 3. The line setting means inserts into the transmitting side a transmission selector for transmitting the working path and the protection path, and an OH (over head) insertion for transmitting the line fault information detected by the receiving side to the opposite side. Section, a transmission control section that controls these sections, a reception monitor that monitors a path failure on the receiving side, a path switching control section that controls path switching based on the line failure result,
And the standby path access device according to claim 1 or 2, characterized in that it has a terminal node comprising a receiving selector for selecting the reception side path as working / spare for each output.