JP3241337B2 - Failure recovery method and transmission apparatus by switching path ends in wavelength division multiplexing transmission network - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission device configuration method using a wavelength multiplexing technique and a fault recovery method in a wavelength division multiplexing network.

[0002]

2. Description of the Related Art With the spread of the Internet and multimedia communication, a demand for a large-capacity communication channel is increasing. Wavelength division multiplexing (hereinafter, WDM) for multiplexing and transmitting a plurality of wavelengths on one optical fiber.
xing) is expected as a technique for performing large-capacity communication. At the same time, "SONET, GR-1230-CORE, ISSUE"
3 DECEMBER, 1996, published by Bellcore ", there is a need for a highly reliable protection method. Even in WDM transmission networks," Multi-wavelength Surviva
ble Ring Network Architectures, AF Elrefaie, IC
C'93 pp. 1245-1251 "is under consideration.

A conventional WDM transmission network protection scheme will be described with reference to FIGS. For the sake of simplicity, a bidirectional fiber is used as an expression below, but the function does not change even if it is separated as a unidirectional fiber.

FIG. 15 shows a configuration of a conventional transmission device. The transmission device in FIG. 15 includes a switch (Line S)
W) 110, 111 and signaling demultiplexer 12
0, 121, wavelength division multiplexing / demultiplexing units 130, 131, failure detection units 140, 141, signaling processing unit 150, and SW control unit 160.

[0005] Input / output ports 201-i, 201-i + 1,
202-i and 202-i + 1
Reference numerals 1-i and 201-i + 1 denote input / output ports connected to a working physical path connecting adjacent transmission apparatuses, and a virtual communication path (hereinafter, referred to as a communication path) connecting arbitrary transmission apparatuses using a wavelength. A wavelength multiplexed signal obtained by multiplexing the working system of a lightwave path) is output. Also, the input / output ports 202-i,
Similarly, reference numeral 202-i + 1 denotes an input / output port connected to the protection path, and outputs a wavelength multiplexed signal obtained by multiplexing the protection light path of the working light path.

In a normal state where no failure occurs, the input / output ports 201-i and 201-i + 1 (hereinafter collectively referred to as 2
01) is a Line signal.
The signals are input to the signaling demultiplexers 120 and 121 via the SWs 110 and 111, respectively. Also, Lin
Some WDM signals from the e-SWs 110 and 111 are input to the failure detection units 140 and 141. The signaling multiplexing / demultiplexing units 120 and 121 separate the signaling signal from the transferred WDM signal, and
And the data WDM signal, which is the remaining data component, is transferred to the wavelength division multiplexing / demultiplexing units 130 and 131. The data WDM signals input to the wavelength multiplexing / demultiplexing units 130 and 131 are separated into lightwave paths of each wavelength, and lightwave paths of wavelengths terminated by the illustrated transmission device are output from the input / output ports 101 and 102 and are not terminated. The lightwave path of the wavelength is transferred to the wavelength division multiplexing / demultiplexing units 131 and 130, respectively.

The wavelength multiplexing / demultiplexing units 130 and 131 multiplex the lightwave paths of these wavelengths with the lightwave paths of the wavelengths input from the input / output ports 101 and 102 to generate a data WDM signal, , 121. Signaling demultiplexing sections 120 and 121 multiplex a signaling signal transferred from signaling processing section 150 into a data WDM signal to form a WDM signal. After that, the WDM signal is output to Line SW11.
0, 111 via the input / output ports 201-i, 201
Output from -i + 1.

Next, a series of operations performed when a failure occurs until recovery from the failure ends will be described with reference to FIG.

FIG. 16 is a diagram showing the configuration of a physical / lightwave path network, and FIG. 16 (a) shows transmission devices 210, 220, 230, 240, and 25 having the configuration shown in FIG.
0 is the working fiber 201-1 which is the working path of the lightwave path.
1 shows a configuration of a physical network connected in a ring shape by using a spare fiber 202-1 to 202-5, which are spare paths of an optical path, and spare fibers 202-1 to 202-5. On the physical network shown in FIG. 16A, a lightwave path 260 using the working fiber 201-3 is set between the transmission devices 220 and 230 as shown in FIG. 16B.

In the network shown in FIG. 16B, the working / standby fiber 201 between the transmission devices 220 and 230
FIG. 15 shows a case where a failure has occurred in -3 and 202-3.
This will be described with reference to FIG.

[0011] As shown in FIG.
0/230 working / standby fiber 201-3, 202
-3, the failure detection units 141 and 14 of the transmission devices 220 and 230 as shown in FIG.
0 detects a failure at time t0 due to a decrease in the light amount of the WDM signal, and the signaling processing unit 15 in its own transmission apparatus respectively.
Notify 0. At time t1, the signaling processing unit 150 generates Line path switching request information. After that, the transmission devices 220 and 230 transmit the Li
ne path switching request information 310, 311 and 320, 321
To transfer.

At time t5, the Line path switching request information 32
Signaling processing unit 15 of the transmission device 220 that has received 1
0 is the Line SW 111 via the SW control unit 160
Is used as the return mode, and the signaling demultiplexer 121
The connection between the current fiber 201-3 and the working fiber 201-3 is changed to the connection between the signaling demultiplexer 121 and the Line SW 110. Similarly, the signaling processing unit 150 of the transmission device 230 that has received the Line path switching request information 310 sets the Line SW 110 to the return mode via the SW control unit 160, and connects the signaling demultiplexing unit 120 to the working fiber 201-3. To the signaling demultiplexer 12
0 is changed to the connection between Line SW111.

Thereafter, at time t6, the transmission devices 220 and 23
The 0 signaling processing unit 150 sends the Line path switching response information 330, 331 and 340, 341 respectively as the transmission destination. As a result, as shown in FIG. 16C, the spare fibers 202-2, 202-1 and 202-
Transmission devices 210, 250, 24 using 5,202-4
A path is formed as a substitute for the lightwave path 260 via 0, and the path recovers from the failure.

[0014]

In a WDM transmission network, a failure of a light source or a receiver of a wavelength used may be considered. In the conventional method, a failure is detected in the WDM signal after the wavelength is multiplexed. However, in this case, the failure is simply detected, and the individual failure detection is not performed for each signal of each wavelength. In the fault recovery work, first, the faulty light source or receiver must be checked and identified for each wavelength, and then the recovery work must be performed. Thus, there is a problem that the fault cannot be recovered efficiently. .

[0015] Further, in order to avoid the use of the working fiber in the faulty section, the lightwave path is switched to the spare fiber of the transmission device adjacent to the faulty section to form a detour path, so that the transmission distance of the lightwave path becomes longer, There is a problem that the size of the network is limited.

In the same network as in FIG. 16A, lightwave paths 401 and 402 composed of wavelengths λj and λk are respectively provided as shown in FIG.
0 and 240, and between the transmission devices 220 and 230 using the working fiber 201.
It is assumed that a failure occurs between 20 and 230. Since the light quantity of the WDM signal is reduced due to this obstacle, the transmission apparatus 210, 220,
The failure detection unit 140 or 141 of 230 or 240 detects a failure on the working fiber 201.

As a result of the failure recovery sequence shown in FIG. 18B, the line switches 111 and 110 on the failure side are respectively switched in the transmission devices 210 and 240. At this time, as shown in FIG. 22
0, 230, each transmission device 2 is used to form a bypass lightwave path 401.
Transmission devices 210, 2 which are the anti-failure side of 20, 230
There is a problem that the failure cannot be recovered from being turned back at 40.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and a method for detecting a fault for each lightwave path in a WDM transmission network and recovering the fault for each lightwave path, and WD for realizing
A first object is to provide an M transmission device.

Further, when a fault in the recoverable lightwave path occurs, the fault can be reliably recovered.
In a normal state where no failure occurs, an additional data path (hereinafter referred to as ET (Ext) is
It is an object of the present invention to provide a failure recovery method capable of setting a lightwave path (referred to as “ra Traffc)).

[0020]

According to the present invention, there is provided a failure recovery system by switching path ends in a wavelength division multiplexing transmission network, comprising a plurality of wavelength division multiplexing transmission devices (hereinafter referred to as transmission devices) connected in a ring. A communication path (hereinafter, a lightwave path) composed of an arbitrary physical wavelength can be set bidirectionally in an arbitrary section of a plurality of wavelength division multiplex transmission apparatuses, and a lightwave path normally used (hereinafter, a working lightwave path) A lightwave path used as a detour when a failure occurs in the working lightwave path (hereinafter referred to as a protection lightwave path)
At least one or more is defined, and in normal times, the network resources allocated to the backup lightwave path set an optional lightwave path for the purpose of additional or auxiliary use (hereinafter referred to as an ET lightwave path) as necessary. A signaling channel for transferring path switching control information for switching from the working lightwave path to the backup lightwave path in the event of a failure or a signaling path multiplexed with a signaling channel is used as a network resource for a wavelength set between the transmission devices. In the failure recovery method based on path end switching in a division multiplex transmission network, each transmission device is configured such that a transmission device that terminates a predetermined lightwave path detects a failure based on a signal reception state of the lightwave path, and When a failure in the working lightwave path is detected, A path switching function of changing Ri has a signaling processing function of exchanging with the signaling channel control information for the path switching by the path switching function, when the working optical path fails, the failure occurs The terminal transmission device (hereinafter referred to as a failure detection transmission device) that has detected a failure in the working lightwave path (hereinafter referred to as a failure lightwave path) selects one or more available backup lightwave paths from a plurality of backup lightwave paths, and the other transmission apparatus serving as the end point (hereinafter disorders optical path opposing transmission device) and both ends transmission device (hereinafter ET light wave path terminated transmission device) of the pre light wave path ET light wave path requiring stops per used to set Available for
Notifies the path switching request information including the pre light wave path information selected as the ability, ET light wave path terminated transmission device stops using the ET light wave path when receiving the path switching request information, before
The optical fiber path opposing transmission device receives the path switching request information
Then, the selected backup lightwave path is determined as one, and the path switching is performed.
After execution, path switching including the determined backup lightwave path information
Request response information is transmitted to the ET
The ET lightwave path terminal transmission device notifies the detection
When the switch request information is received, the determined standby lightwave is
Refers to the path information and sets the backup lightwave path and its own transmission device.
ET lightwave path that terminates the network shares network resources
If the network resource is determined
Assigned to the optical path, resumes the use of the ET lightwave path, the failure detection transmission device that has received the path switching response information, by performing a path switch to the backup lightwave path described in the path switching response information, by lightwave path unit Disaster recovery is characterized.

In this case, the working lightwave paths are all constituted by a single physical wavelength, and the backup lightwave path corresponding thereto is constituted by a single physical wavelength which is the same as or different from the physical wavelength constituting the working lightwave path. By forming a wavelength group formed by one or more limited physical wavelengths used in the lightwave path and a plurality of backup lightwave paths corresponding thereto, the fault recovery of the faulty lightwave path can be performed in parallel for each wavelength group. You may do it.

Further, a backup lightwave path may be provided to the working lightwave path through a different path from the working lightwave path, or may be provided at a different physical wavelength from the working lightwave path, or a combination of both may be provided depending on the situation. .

In any of the above cases, when there are a plurality of backup lightwave paths for the working lightwave path, the selection order is set in advance for these protection lightwave paths, and the fault detecting and transmitting apparatus performs the fault lightwave transmission in accordance with the order. A backup lightwave path for performing path recovery may be sequentially selected.

Furthermore, the selection order of the backup lightwave path may be set according to the number of hops, the transmission distance, the efficiency of network resources, or the probability of failure recovery.

Also, a bidirectional fault occurs in a predetermined lightwave path, and one or a plurality of pieces of backup lightwave path information notified by path setting request information from each of the plurality of fault detection transmission devices terminating the faulty lightwave path. If different, the transmission device terminating the fault lightwave path may be determined to be one protection lightwave path based on a predetermined order from the notified protection lightwave path and the selected protection lightwave path.

Further, the network resources allocated to the protection lightwave path of the predetermined working lightwave path are used as the protection lightwave path of another working lightwave path, and the path switching request information and the path switching response information are used as the protection lightpath of the faulty lightwave path. A transmission device at both ends of a working lightwave path that shares some or all of the network resources of the protection lightwave path used for switching as part or all of the network resources of its own protection lightwave path (hereinafter referred to as a protection lightwave path shared transmission device) ), The backup lightwave path shared transmission device deletes the backup lightwave path from the backup lightwave path candidates of the working lightwave path terminated by the own transmission device, and dynamically changes the order of the backup lightwave paths. Is also good.

A transmission device for terminating a certain lightwave path
However, a lightwave path termination processing function and a plurality of backup lightwave paths of a failed lightwave path can be set as a path switching function of switching to the backup lightwave path when a failure of the working lightwave path is detected, and the signaling processing function is used for path switching. In addition to the control information for the optical path setting, path setting information for more optimal light wave path setting can be exchanged by using the signaling channel. After switching from the path to the backup lightwave path and recovering from the failure, the switched backup lightwave path (hereinafter, referred to as
An ET lightwave path termination that uses some or all of the network resources of the optimal backup lightwave path when the first backup lightwave path) and the backup lightwave path determined to be optimal as the backup lightwave path (hereinafter referred to as the optimal backup lightwave path) are different. Notifying the optimum backup lightwave path setting request to the faulty lightwave path opposite transmission device with the transmission device, the ET lightwave path terminal transmission device stops using the ET lightwave path when receiving the optimum lightwave path setting request information. Receiving the optimum backup lightwave path setting request information, the faulty lightwave path opposing transmission device sets the transmission and reception of the optimum protection lightwave path, and then sets the optimum protection lightwave path including a result of setting the optimum protection lightwave path. Setting request response information is notified to the ET lightwave path terminal transmission device and the failure detection transmission device, and the ET lightwave path terminal transmission device transmits the optimum path setting information. When the request response information is received, the setting result of the optimal backup lightwave path is referred to, and when the optimal backup lightwave path is set, the network resource allocated to the ET lightwave path is allocated to the optimal backup lightwave path, and the optimal standby lightwave path is allocated. When the lightwave path is not set, the use of the ET lightwave path is resumed, and when the failure detection transmission device that has received the optimum backup lightwave path setting request response information has the optimum protection lightwave path set, Alternatively, bidirectional switching from the first backup lightwave path to the optimal backup lightwave path may be performed, and the failure detection transmission device and the transmission device facing the failed lightwave path may release the first backup lightwave path.

In this case, when a failure of a predetermined working lightwave path is detected, the failure detection transmission device transmits an optimum protection lightwave path setting request and an optimum protection lightwave path setting response to the ET lightwave path when the first protection lightwave path is set. It also notifies the ET lightwave path terminating transmission device that has stopped using it, recognizes that the first backup lightwave path is released when it receives the optimal backup lightwave path setting response, and recognizes the stopped ET lightwave path. Use may be resumed.

Further, the transmission apparatus has an optimum backup light path test function for setting an optimum protection light path and performing an appropriate test of the optimum protection light path using the test signal. After establishing the optimal backup lightwave path in both directions, the opposing transmission device determines whether or not the optimal backup lightwave path can be used by transmitting and receiving test signals to and from each other using the optimal backup lightwave path. After stopping the use of the test signal when the lightwave path opposite transmission device determines that the optimal backup lightwave path can be used together,
The first standby lightwave path may be switched to the optimal standby lightwave path.

Further, the working lightwave path is constituted by a single physical wavelength, and the protection lightwave path corresponding thereto is constituted by a single physical wavelength which is the same as or different from the physical wavelength constituting the working lightwave path. By forming a wavelength group formed by one or a plurality of limited physical wavelengths used in a path and a plurality of backup lightwave paths corresponding thereto, failure recovery may be performed in parallel for each wavelength group. .

Also, for the working lightwave path, the first protection lightwave path or the optimum protection lightwave path is provided by a different path from the working lightwave path, or by a physical wavelength different from the working lightwave path, or both depending on the situation. May be combined.

When there are a plurality of backup lightwave paths of a certain working lightwave path, the selection order is set in advance for these protection lightwave paths. A path and an optimal backup lightwave path may be selected.

Further, the selection order of the first backup lightwave path and the optimum backup lightwave path may be set according to the number of hops, transmission distance, efficient use of network resources, or failure recovery probability.

Further, a bidirectional fault occurs in a certain lightwave path, and one or a plurality of backup lightwave path information notified by path setting request information from each of the plurality of fault detection transmission devices terminating the faulty lightwave path is different. In the case where the optimal spare light path information notified by the optimal spare light path setting request information is different, the transmission device that has received the spare light path information or the optimal spare light path information is notified of the spare light path information or the optimal spare light wave. One may be determined from the path information and the backup lightwave path selected by the own transmission apparatus or the optimum backup lightwave path based on a predetermined order.

Further, network resources allocated to a backup lightwave path of a certain working lightwave path are used as backup lightwave paths of another working lightwave path, and path switching request information, path switching response information, and optimum backup lightwave path test result information are used. A transmission device at both ends of a working lightwave path that shares a part of the protection lightwave path used as a detour of the faulty lightwave path as the protection lightwave path (hereinafter referred to as a protection lightwave path shared transmission device). ), The backup lightwave path in which the backup lightwave path shared transmission device is used is deleted from the first backup lightwave path candidate and the optimum backup lightwave path candidate of the working lightwave path terminated by the own transmission device, and the backup lightwave The order of the paths may be dynamically changed.

The transmission apparatus according to the present invention is a transmission apparatus constituting a failure recovery system by switching path ends in the wavelength division multiplexing transmission network. The transmission apparatus separates a wavelength division multiplexed signal into lightwave paths for each wavelength, and separates the separated lightwaves. The wavelength division multiplexing / demultiplexing unit that multiplexes the transmitted light wave path and the light wave path newly inserted from the own transmission device among the paths, and the light wave path separated by the wavelength division demultiplexing unit are transferred and terminated in the own transmission device. Take the lightwave path into its own transmission device, transfer the lightwave path not terminated in its own transmission device to the wavelength division multiplexing / demultiplexing unit,
The ADM unit transfers the lightwave path generated by the own transmission device to the wavelength division multiplexing / demultiplexing unit, and switches the lightwave path captured and transferred by the ADM unit or the lightwave path generated by the own transmission device. A lightwave path switch unit, a lightwave path termination processing unit that detects a failure of the lightwave path terminated by the own transmission device transferred from the lightwave path switch unit, and performs a termination process of the lightwave path generated by the own transmission device; A signaling multiplexing / demultiplexing unit that multiplexes a signaling channel from a lightwave path transferred from the lightwave path termination processing unit to a signaling channel or a lightwave path generated by the own transmission device, and receives fault information from the lightwave path termination processing unit or Receiving information transferred from another transmission apparatus by a signaling channel separated by the signaling demultiplexer, and Generating information for path switching using a signaling processing function, transferring the information to a signaling multiplexing / demultiplexing unit through a signaling channel to another transmission device, and controlling the ADM unit and the lightwave path switching unit. A signaling processing unit for switching the path of the lightwave path passing through the own transmission device to the backup lightwave path by changing the path and wavelength of the faulty lightwave path, and one upon receiving a backup lightwave path selection request from the signaling processing unit. Alternatively, a plurality of backup lightwave path candidates are selected, and
When receiving a backup lightwave path selection decision request including a plurality of backup lightwave path information from the signaling processing unit, the backup lightwave path selection unit selects one of the plurality of backup lightwave paths and notifies the signaling processing unit of the selection. It is characterized by the following.

A transmission apparatus according to another aspect of the present invention is a transmission apparatus that constitutes a failure recovery system by switching path ends in the above-described wavelength division multiplexing transmission network, wherein the transmission apparatus transmits a lightwave path transferred from the lightwave path termination processing unit. A signaling multiplexing / demultiplexing unit for multiplexing a signaling channel into a signaling channel or a lightwave path generated by the own transmission device; and a lightwave path for signaling path transfer and a lightwave path for data transfer from an input wavelength multiplexed signal, and separation. The data transfer lightwave path is transferred as an input signal to the wavelength division multiplexing / demultiplexing unit, and the signaling path generated by its own transmission device for signal path transmission and the WDM signal transferred from the wavelength division multiplexing / demultiplexing unit are multiplexed with the signaling path. A demultiplexing unit, and a signaling path transferred from the signaling path demultiplexing unit. Terminates the lightwave path for transfer, separates the signaling channel to be processed from the signaling path, transmits the signaling channel that is not processed, and remultiplexes these with the signaling channel that has been subjected to signaling processing in its own transmission device to perform the signaling path. A signaling path terminator that generates a lightwave path for transfer and then transfers it to a signaling path demultiplexer, and a lightwave path to which the lightwave path separated by the wavelength demultiplexer is transferred and terminated by its own transmission device. An ADM unit that takes in the transmission device and transfers an optical path not terminated by the own transmission device to the wavelength division multiplexing / demultiplexing unit, and transfers an optical wave path generated by the own transmission device to the wavelength division multiplexing / demultiplexing unit; Lightwave path that switches the path of the lightwave path captured and transferred by Switch unit, and a lightwave path termination processing unit that detects a failure of the lightwave path terminated in the own transmission device transferred from the lightwave path switch unit, and performs termination processing of the lightwave path generated in the own transmission device, The failure information is received from the lightwave path termination processing unit or the information transferred from another transmission device by the signaling channel separated by the signaling termination processing unit is received, and information for path switching is performed using a signaling processing function. And transfers the information to another transmission device through a signaling channel to a signaling termination processing unit, and controls the ADM unit and the lightwave path switch unit to control the path of the lightwave path via the own transmission device. A signaling processing unit for switching a fault lightwave path to a backup lightwave path by changing a wavelength; Upon receiving a backup lightwave path selection request from the ring processing unit, one or more backup lightwave path candidates are selected, and when receiving a backup lightwave path selection decision request including a plurality of backup lightwave path information from the signaling processing unit, a plurality of backup lightwave path selection requests are received. It is characterized by comprising a backup lightwave path selection unit that selects one of the backup lightwave paths and notifies each of them to the signaling processing unit.

In any of the above, the signaling processing unit may be arranged for each wavelength group, and may execute the fault recovery for each wavelength group.

Further, a test of the optimal backup lightwave path is performed by transmitting and receiving the test signal of the optimal backup lightwave path according to claim 8 under the control of the signaling processing unit, and a lightwave path test for notifying the result to the signaling processing unit. It may have a part. In this case, the lightwave path test unit may be arranged for each wavelength group terminated in the own transmission device, and may perform the fault recovery for each wavelength group.

The backup lightwave path selector has backup lightwave path information for each wavelength group, and sets the selection order of the backup lightwave paths according to the number of hops, transmission distance, efficient use of network resources, or failure recovery probability. Alternatively, in response to a request for selecting a backup lightwave path from the signaling processing unit, one or more backup lightwave paths that are higher in the order may be notified.

Further, in response to the backup light path selection decision request notified from the signaling processing unit , the backup light path selection unit determines one backup light wave path from a plurality of backup light wave path candidates based on a predetermined order. You may do it.

[0042]

Next, an embodiment of the present invention will be described with reference to the drawings.

First Embodiment FIGS. 1 to 9 are views for explaining a first embodiment of the present invention. FIG. 1 shows transmission devices 510, 520, 530, 5
FIG. 2 shows a WDM transmission network using 40,550. FIG. 1A is a connection diagram of a physical network, and FIG. 1B shows a network of a lightwave path (hereinafter referred to as a working lightwave path) used at normal times using wavelengths λi and λj.

As shown in FIG. 1A, the transmission device 510,
520, 530, 540, and 550 are bidirectional fibers 501-1 to 501-5 (hereinafter collectively referred to as 501).
), And are connected in a ring shape using 502-1 to 502-5 (hereinafter, these are collectively referred to as 502). On the physical transmission network of FIG.
As shown in (b), a working lightwave path 560-N of wavelength λi passing through the transmission device 550 is set between the transmission device 510 and the transmission device 540. A working lightwave path 561-N of wavelength λi passing through the transmission devices 520 and 530 is set between the transmission devices 510 and 540. Between the transmission devices 520 and 530, a working lightwave path 570-N of wavelength λj passing through the transmission devices 510, 550, and 540 is set. Transmission device 520
A working lightwave path 571-N of wavelength λj provided between them and the transmission device 530 is set, and a total of four working lightwave paths are set.

All of the above working lightwave paths 560-N,
561-N, 570-N, and 571-N are set using the bidirectional fiber 501. Working lightwave path 560-
In each of N, 561-N, 570-N, and 571-N, a lightwave path (hereinafter referred to as a backup lightwave path) used as a detour in the event of a failure is provided on the bidirectional fiber 502 in the span direction (the same direction as the working lightwave path). ) And the ring direction (the direction opposite to the working lightwave path) are physically prepared, but are not logically set. In the present embodiment, the wavelengths of the working lightwave paths 560-N and 561-N and the backup lightwave paths for them are the same λi, and the working lightwave path 570-N is used.
−N, 571-N and the wavelength of the backup lightwave path for them are the same λj.

In this embodiment, the wavelength of the working lightwave path and the wavelength of the protection lightwave path corresponding thereto are the same, but these wavelengths may be different. Further, in the present embodiment, a single physical wavelength is used between the physical links on the lightwave path in order to configure one lightwave path, but this may be a combination of different wavelengths. Absent. That is,
It is only necessary that wavelength resources are independently assigned to the working lightwave path and the backup lightwave path. Taking this into consideration, a wavelength group consisting of the wavelengths of the working lightwave path and the backup lightwave path is defined as a wavelength group and used below.

In this embodiment, two wavelength groups are used, and the number of wavelengths constituting each wavelength group is one.
Also, the transmission devices 510, 520, 530, 540, 55
0 has a lightwave path termination processing function for detecting a failure of the lightwave path terminated by the transmission apparatus, a lightwave path switching function for switching the lightwave path, and a signaling processing function for lightwave path switching control information exchange. It is assumed that

The signaling processing function is provided for each wavelength group, and each transmission device 510, 520, 53
It is assumed that 0, 540, and 550 have at least the signaling processing function of the wavelength group to which the lightwave path terminating in the own transmission apparatus belongs. It is also assumed that a signaling channel for transferring path switching information is set between adjacent transmission apparatuses having the same wavelength group.

As shown in FIG. 1C, the transmission device 520
Bidirectional fiber 5 provided between the transmission device 530
A case where a fiber failure has occurred in 01-3 will be described.

When a fault occurs in the working lightwave paths 561-N and 571-N passing through the bidirectional fiber 501-3 due to a fault, the fault occurs at both ends of the working lightwave paths 561-N and 571-N. Transmission device 510,
540 and transmission devices 520, 530. Each of the transmission devices 510, 520, and 53 that has detected a failure
0, 540 activates the fault recovery process. The failure recovery process is performed for each wavelength group.

FIGS. 2 and 4 are diagrams showing a fault recovery information exchange sequence for fault recovery in this embodiment. FIG. 2 is a diagram showing a failure recovery information exchange sequence of a wavelength group of wavelength λi, and FIG. 4 is a diagram showing a failure recovery information exchange sequence of a wavelength group of wavelength λj.
The fault recovery information exchange sequence of each wavelength group is independent and executed in parallel.

First, the failure recovery information exchange sequence and the path switching operation of the wavelength group of the wavelength λi in FIG. 2 will be described. When a failure occurs between the transmission device 520 and the transmission device 530 as shown in FIG. 2A, as shown in FIG. 2B, the transmission device 510 and the transmission device 540 that have detected the failure at time t0 One or more available backup lightwave paths are selected, and path switching request information 610, 61 including the selected backup lightwave path information at time t1.
1 and 620, 621 are respectively connected to the working lightwave paths 561-N.
To the transmission devices 540 and 510 at the other end of the transmission.

At time t3, path switching request information 621, 61
0, each of the transmission devices 510 and 540 determines one of the notified selected backup lightwave path and the backup lightwave path selected by the own transmission device, and sets the reception path to the backup lightwave path determined from the working lightwave path. Switching, path switching response information 630, 6 including backup lightwave path information determined at time t4
31 and 640, 641 are connected to opposing working lightwave paths 561-N.
To the transmission devices 540 and 510 at the other end.

At time t6, path switching response information 641, 63
The transmission devices 510 and 540 that have received 0 switch the transmission side path of the working lightwave path 561-N to the determined backup lightwave path. As a result, at time t6, FIG.
(C) A backup lightwave path 561-R is set bidirectionally as (backup lightwave path 1) and (backup lightwave path 2) shown in (c), respectively, and switched from the working lightwave path 561-N.
The communication path between the transmission device 510 and the transmission device 540 recovers from the failure. In FIG. 3 (preliminary lightwave path 1), the preliminary lightwave path 561-R is a bidirectional fiber 5 in the span direction.
02 is set. In addition, in the (preliminary lightwave path 2) of FIG.
The setting is made by using a bidirectional fiber 502 in the ring direction passing through “0”.

The failure recovery information exchange sequence and the path switching operation of the wavelength group of wavelength λj shown in FIGS. 4A and 4B are the same as those of the wavelength group of wavelength λi shown in FIG. However, the transmission devices that exchange the path switching control information are the transmission device 520 and the transmission device 530.

FIG. 5 shows a setting example of the backup lightwave path 571-R set for the wavelength λj. FIG. 5 (b)
(Preliminary lightwave path 1) shown in FIG.
1-R is set using the bidirectional fiber 502 in the span direction. Also, in the (preliminary lightwave path path 2) shown in FIG. 5C, the backup lightwave path 571-R is transmitted using the bidirectional fiber 502 in the ring direction.
50 and 540 are set.

As described above, in the ring configuration of the present embodiment, there are at least two paths in the span direction / ring direction as candidates for the backup lightwave path.

When one or more spare lightwave path candidates are selected at the time of detecting a failure, or when one of a plurality of spare lightwave path candidates is selected by exchanging path switching request information, these are selected in accordance with a predetermined order. Select
Examples of criteria for this ranking include the number of hops, transmission distance, failure recovery probability, and network resource use efficiency.

The switching from the working lightwave path to the backup lightwave path can be performed by wavelength switching other than the physical path switching described above. In this case, the wavelength group is composed of a plurality of wavelengths, and the switched backup lightwave path may be physically the same path as the working lightwave path path.

When the backup lightwave path is not used, an ET lightwave path is constructed by using network resources of some or all of the paths / wavelengths of the backup lightwave path in order to increase the network utilization rate. Auxiliary signals can be transferred. When the ET lightwave path uses part or all of the backup lightwave path selected for failure recovery at the time of a failure, path switching request / response information is also notified to the terminal transmission device of the ET lightwave path. When there are a plurality of backup lightwave path candidates, the corresponding ET lightwave path terminal transmission devices are notified of them. Upon receiving the path switching request information, the ET lightwave path terminal transmission
Stop using the T lightwave path. Further, upon receiving the path switching request response information, if the backup lightwave path finally determined as a detour shares network resources with the ET lightwave path whose use has been stopped, the backup lightwave path is set. Conversely, when the backup lightwave path finally determined as the detour does not share network resources with the ET lightwave path whose use has been stopped, the use of the ET lightwave path is resumed.

As described above, a wavelength group is formed by the wavelengths of the working lightwave path and the protection lightwave path, a fault is detected at the lightwave path end, and path switching information for fault recovery is exchanged for each wavelength group. The failure recovery can be performed by switching from the failed working lightwave path to the backup lightwave path.

Next, the transmission devices 510, 520, 530, 540, and 55 for performing the fault recovery performed in this embodiment.
0 will be described with reference to FIG. 6 showing the configuration. It is assumed that the WDM transmission network to which the transmission device shown in FIG. 6 is applied has four wavelengths. In the transmission device of FIG. 6, a signaling channel is multiplexed on a lightwave path together with main signal data.

The transmission device shown in FIG.
0 to 1013 and a branch coupler (hereinafter referred to as ADM (Add-D
rop Multiplexer) 1020
, 1023 to 1023, lightwave path SWs 1040 and 1041, lightwave path termination processors 1060 to 1063, signaling demultiplexers 1070 to 1073, signaling processors 1050 and 1051, and SW controllers 1030 and 1031.
And a backup lightwave path selection unit 1080. The lightwave path termination processing units 1060 to 1063 are arranged only on the lightwave path terminated by the transmission device shown in FIG. Further, the light wave paths SW1040 and 1041 and the SW control unit 10
30, 1031 and signaling processing units 1050, 105
1 is prepared for each wavelength group terminated by the transmission device shown in FIG.

The input / output ports 501-i and 501-i + 1
(Hereinafter abbreviated as 501), 502-i, 502-
W input from i + 1 (hereinafter abbreviated as 502)
The DM signal is separated by the wavelength division multiplexers 1010 to 1013 into lightwave paths of each wavelength. The separated lightwave paths are classified into a lightwave path of a wavelength group that passes through the transmission device shown in FIG. 6 and a lightwave path of a wavelength group that is terminated.

The lightwave path of the wavelength group transmitted through the transmission apparatus shown in FIG.
Transferred to 10 to 1013.

The lightwave path of the wavelength group terminated by the transmission device shown in FIG. 6 is transferred to ADMs 1020 to 1023. The lightwave path terminated in the transmission device shown in FIG. 6 is dropped in the ADMs 1020 to 1023 and transferred to the signaling demultiplexing units 1070 to 1073 via the lightwave paths SW1040 and 1041 and the lightwave path termination processing units 1060 to 1063. Are demultiplexed into signaling channels and data paths in signaling demultiplexing sections 1070 to 1073. The signaling channel is transferred to signaling processing units 1050 and 1051, and the data path is output from input / output ports 1001 to 1004. Lightwave paths that are not terminated in the transmission device illustrated in FIG. 6 are transmitted through ADMs 1020 to 1023 and transferred to wavelength multiplexing / demultiplexing units 1010 to 1013.

Input / output port 1 of the transmission device shown in FIG.
The data path input from 001 to 1004 is multiplexed with the signaling channels from the signaling processing units 1050 and 1051 by the signaling multiplexing / demultiplexing units 1070 to 1073, and thereafter, the optical path termination processing units 1060 to 1063.
Is converted into a desired lightwave path by the lightwave path SW1040,
The signal is inserted by the ADMs 1020 to 1023 via the 1041 and transferred to the wavelength division multiplexers 1010 to 1013.

The wavelength division multiplexing / demultiplexing units 1010 to 1013 multiplex the lightwave paths transmitted or inserted in the transmission apparatus shown in FIG.
02.

The lightwave path termination processing function at the lightwave path end in the present embodiment whose operation has been described with reference to FIGS. 1 to 5 is realized by the lightwave path termination processing units 1060 to 1063. The signaling processing function for performing path switching control such as switching is performed by the signaling processing unit 10.
50, 1051. In addition, the path end switching function at the time of failure is provided by the signaling processing unit 1050,
Reference numeral 1051 denotes a desired ADM 1020 to 1023 and a lightwave path SW 1040 via the SW control units 1030 and 1031.
This is realized by switching 1041. If the backup path switching of the lightwave path is the switching of the physical path route, it is desirable that the lightwave paths SW1040 and 1041 be realized by a space switch, and if the switching is the wavelength switching, it is desirable to be a wavelength conversion switch. If both are mixed, they must have both switch functions.

The backup lightwave path selection unit 1080 has backup lightwave path information for each wavelength group, and can be used in response to a path selection request for a protection lightwave path for a certain working lightwave path from the signaling processing units 1050 and 1051. One or a plurality of backup lightwave path candidates are notified according to the order of determination of the number of hops, the transmission distance, and the efficient use of network resources among the lightwave paths.

The backup lightwave path selection unit 1080 is configured to transmit the selected backup lightwave path notified from the transmission device that terminates the other end of the same working lightwave path notified from the signaling processing units 1050 and 1051 and the backup lightwave selected by the own transmission device. If the paths are different, the two paths are compared to uniquely determine a backup lightwave path and notify the signaling processing units 1050 and 1051.

When part or all of the backup lightwave path is used as the ET lightwave path in the normal state, the signaling processing units 1050 and 1051 of the transmission apparatus shown in FIG. Upon receiving the switching request information, the desired ADM units 1020 to 1023 are switched to the transparent state. With this operation, the use of the ET lightwave path is stopped and the setting of the backup lightwave path is performed. Thereafter, the signaling processing units 1050 and 105 of the transmission device shown in FIG.
Reference numeral 1 denotes a desired ADM unit 102 when the path switching request response information is received and the target ET optical path and the finally determined backup optical path do not share network resources.
Switching from 0 to 1023 resumes the use of the ET lightwave path.

With the transmission device having the above configuration, the failure recovery in the first embodiment can be realized.

FIG. 7 is a diagram showing another configuration example of the transmission devices 510, 520, 530, 540, and 550 for performing the first embodiment. It is assumed that the WDM transmission network to which the transmission device shown in FIG. 7 is applied has five wavelengths. The transmission device shown in FIG. 7 uses four wavelengths as lightwave paths for data transfer and one wavelength as a lightwave path for signaling path transfer in which a signaling channel is multiplexed. The transmission device shown in FIG. 7 transfers the signaling channel through another lightwave path without multiplexing the signaling channel into the lightwave path for main signal data transfer.

The transmission apparatus shown in FIG. 7 is different from the transmission apparatus shown in FIG.
113 and a signaling channel demultiplexing section 1120 are newly added, and signaling demultiplexing sections 1070 to 107 are added.
3 is deleted from the transmission apparatus shown in FIG. 6, and therefore, only the difference from the transmission apparatus shown in FIG. 6 will be described in the following description.

Signaling path demultiplexing sections 1110-1
Reference numeral 113 separates the WDM signals from the input / output ports 501 and 502 into a signaling path transfer lightwave path and a data transfer lightwave path, transfers the signaling path transfer lightwave path to the signaling channel demultiplexer 1120, and performs data transfer. Multiplexing / demultiplexing units 11010 to 1111
13 is transferred. Also, the signaling path demultiplexing unit 1
110 to 1113 are signaling channel demultiplexing units 1
The lightwave path for signaling path transfer from the H.120 and the lightwave path for data transfer from the wavelength multiplexing / demultiplexing units 1010 to 1013 are multiplexed and transferred to the input / output ports 501 and 502.

Signaling channel demultiplexing section 1120
Separates the signaling paths from the signaling path demultiplexing units 1110 to 1113 into signaling channels and terminates the wavelength group signaling processing unit 10
50 and 1051. Signaling channel of non-terminated wavelength group and signaling processing unit 105
Signaling channels from 0 and 1051 are multiplexed to form a signaling path, converted into a lightwave path, and transferred to signaling path demultiplexing units 1110 to 1113.

In the transmission apparatus shown in FIG. 7, signaling transfer is performed on a light wave path different from the light wave path for data transfer. Therefore, in the network shown in FIG. 8A having the same configuration as the network shown in FIG. 1A, the lightwave paths 1210 and 1220 of the same wavelength group are respectively placed on the bidirectional fiber 501 by the transmission devices 520,
30 and between the transmission devices 520 and 530 on the bidirectional fiber 502 via the transmission devices 520 and 530, that is, even when the setting sections of the lightwave paths of the same wavelength group partially overlap, By setting the signaling channels 1230-1 to 1230-4 as shown in FIG.
It is possible to exchange path switching information of the wavelength group between 0 and 540. As a result, in the transmission device shown in FIG.
When a signaling channel is multiplexed on a lightwave path, the lightwave paths of the same wavelength group can be set only in the same section or completely different sections. However, the transmission apparatus shown in FIG. Can be set.

As described above, in the transmission apparatus shown in FIG. 7, the failure recovery in the first embodiment can be realized, and the optical path for signaling transfer and the optical path for data transfer are separated from each other. The lightwave path setting of the WDM transmission network can be performed more flexibly as compared with the transmission device shown in FIG.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. 1, and FIGS.

The WDM transmission network shown in FIG.
1 is a physical / lightwave path network for describing an embodiment of the present invention. Transmission devices 510, 520, 530,
540 and 550 have a lightwave path test function in addition to the function described in the first embodiment.

In the present embodiment, the first stage of setting up a backup lightwave path (hereinafter referred to as a first backup lightwave path) using the failure recovery method described as the first embodiment, and the optimal stage in consideration of network efficiency and the like. It is characterized in that it comprises a second-stage process of setting a suitable backup lightwave path (hereinafter referred to as an optimum backup lightwave path) and switching from the first backup lightwave path to the optimum backup lightwave path.

That is, this is a failure recovery method applied when the first backup lightwave path from which the failure has been recovered is not always optimal.

As shown in FIG. 1C, the transmission device 520
When a fiber failure occurs in the bidirectional fiber 501-3 between the 530s, the fault recovery information exchange sequence shown in FIGS. 2 and 4 and the path switching operation described in the first embodiment are performed in exactly the same procedure. , The working lightwave paths 561-N, 571-N suffering the first stage failure
To the first backup lightwave paths 561-R and 571-R.

Then, as a result of considering the network efficiency, if the first preliminary lightwave paths 561-R and 571-R are not optimal, the second-stage preliminary lightwave path optimization is executed. The optimal backup lightwave path is selected based on the number of hops, efficient use of the network, transmission distance, the number of ET lightwave paths to be disconnected, and the like. The setting and testing of the optimal backup lightwave path in the second stage is executed using the signaling processing function and the path test function.

FIG. 9 and FIG. 11 show the second-stage backup lightwave path optimization information exchange sequence of the wavelength group of wavelength λi and the wavelength group of wavelength λj, respectively. This backup lightwave path optimization information exchange sequence is also executed in parallel for each wavelength group as in the first stage.

Referring to FIGS. 9 and 10, a description will be given of the backup lightwave path optimization information exchange sequence and its operation in the second stage of the wavelength group of wavelength λi. After the first-stage failure recovery is completed at time t0, the transmission devices 510, 5
Numeral 40 determines an optimal backup lightwave path, and at time t1, optimal backup lightwave path setting request information 1 including the optimal backup lightwave path.
Send 310 and 1320 to each other. At time t3, the optimum backup lightwave path setting request information 1320, 1310
The transmission apparatuses 510 and 540 that have received the 設定 設定 設定 設定 設定 設定 設定 設定 設定 、 に お い て に お い て に お い て に お い て に お い て に お い て 時刻 に お い て 時刻 時刻 時刻 時刻 時刻 時刻 時刻.

At time t6, transmission apparatus 510 receiving optimum backup lightwave path setting response information 1340, 1330,
540 transmits and receives test signals to and from each other using the optimal backup lightwave path and performs the test. Transmission devices 510, 540
Notify each other of the test results as backup lightwave path test result information 1350 and 1360 at time t7.

At time t10, the transmission devices 510, 5 having received the preliminary lightwave path test result information 1360, 1350
40 transmits the preliminary lightwave path test result response information 1370 and 1380 to each other at time t11. Transmission device 51
At 0 and 540, if it is determined from the backup lightwave path test result response information 1380 and 1370 received at time t14 that the optimum backup lightwave path is usable, the path is switched from the first backup lightwave path to the optimum backup lightwave path.

Thereafter, the transmission devices 510 and 540 release the first backup lightwave path through the backup lightwave path disconnection request / response. Further, the transmission devices 510 and 540 receive the backup lightwave path test result response information 1370 and 1380, and release the optimum backup lightwave path when the optimum backup lightwave path cannot be used as a result.

FIG. 10 shows a lightwave path network of a wavelength group of wavelength λi. FIG. 10A shows the lightwave path network at the end of the first stage, that is, at time t0, in which a first backup lightwave path 561-R using the bidirectional fiber 502 is set in the ring direction.

FIG. 10B shows a lightwave path network between times t10 and t11, and the first backup lightwave path 561-561.
An optimal backup lightwave path 561-RM is set on the bidirectional fiber 502 in the span direction in addition to R. But,
At this point, the test signal is flowing through the optimal backup lightwave path 561-RM, and the data signal to be transferred is transferred using the first backup lightwave path 561-R.

FIG. 10C shows a lightwave path network after time t14, in which the first backup lightwave path 561-R in the ring direction between the transmission devices 510 and 540 is released, and the optimum backup lightwave path 561- in the span direction. Only RM is set.

The second stage preliminary lightwave path optimization information exchange sequence of the wavelength group of wavelength λj shown in FIG. 11 is the same as the wavelength group of wavelength λi. However, the backup lightwave path optimization information exchange sequence is the transmission device 520,
530.

FIG. 12 shows a lightwave path network of a wavelength group of wavelength λj. FIG. 12A shows the lightwave path network at the end of the first stage, that is, at time t0, in which a first backup lightwave path 571-R using the bidirectional fiber 502 is set in the ring direction.

FIG. 12B is a lightwave path network between times t10 and t11, and includes a first backup lightwave path 571-.
An optimum backup lightwave path 571-RM is set on the bidirectional fiber 502 in the span direction in addition to R. But,
At this point, the test signal is flowing through the optimal backup lightwave path 571-RM, and the data signal to be transferred is transferred using the first backup lightwave path 571-R.

FIG. 12C shows the lightwave path network after time t14, in which the first backup lightwave path 571-R in the ring direction between the transmission devices 520 and 530 is released, and the optimum backup lightwave path 571 in the span direction is released. RM is set.

In this embodiment configured as described above, before setting the optimal backup lightwave path, an ET lightwave path is constructed by using the network resources, and additional or auxiliary signals are transferred. be able to. In setting an optimal backup lightwave path, if some or all of the network resources are used by the ET lightwave path, the optimum backup lightwave path switching request / response information is also notified to the terminal transmission device of the ET lightwave path. . Upon receiving the optimum backup lightwave path switching request information, the ET lightwave path terminal transmission device
Stop using the T lightwave path. Thereafter, when receiving the optimal lightwave path switching request response information and using the optimal backup lightwave path, the setting is performed. On the other hand, when the optimal backup lightwave path is not used, the use of the ET lightwave path can be resumed.

Also, when the first backup lightwave path is released through the backup lightwave path disconnection request / response information,
By notifying such information to the two-end transmission device that has set up the ET lightwave path using a part or all of the network resources at normal times, the use of the ET lightwave path can be resumed.

After the first stage of switching from the working lightwave path to the backup lightwave path that has suffered a failure as described above, the second stage of setting the optimum backup lightwave path and switching to the optimum backup lightwave path through a test is executed. Network-efficient failure recovery can be performed.

FIG. 13 shows transmission apparatuses 510 and 5 for performing the above-described failure recovery in the second embodiment of the present invention.
It is a figure which shows the structure of 20, 530, 540, 550.
It is assumed that the WDM transmission network to which the transmission device in FIG. 13 is applied has four wavelengths. In the transmission device shown in FIG. 13, a signaling channel is multiplexed on a lightwave path together with main signal data.

Since the transmission apparatus shown in FIG. 13 has a configuration in which lightwave path test units 1710 and 1711 are newly added to the transmission apparatus shown in FIG. 6, in the following description, the transmission apparatus shown in FIG. Only the differences are described, and the same functional units are omitted.

The lightwave path test units 1710 and 1711 are arranged in units of wavelength groups, and each lightwave path SW104
0, 1041. Lightwave path test section 171
0, 1711 are signaling processing units 1050, 105
By transmitting and receiving a test signal using the optimal backup lightwave path set by the control of No. 1, the state of the optimal backup lightwave path is verified. Also, the result is notified to the signaling processing units 1050 and 1051. The above-described test of the optimal backup lightwave path is performed by the lightwave path test units 1710 and 1711.

Signaling processing units 1050 and 1051
Is the first stage of the failure recovery information exchange sequence, the second stage of the optimal backup lightwave path setting information exchange sequence processing, and the lightwave paths SW1040, 1041, ADM1020.
〜１０1023 to control the lightwave path switching. Since these sequences are as described in each embodiment, the description is omitted here, and the description will focus on the signaling processing units 1050 and 1051 and the lightwave path test units 1710 and 1711 which are newly added functions. .

Signaling processing units 1050 and 1051
Issues a request to search for the optimal backup lightwave path of the failed lightwave path to the backup lightwave path selection unit 1080 after the first-stage failure recovery is completed.

The backup lightwave path selecting unit 1080 selects a path that can efficiently use the network and notifies the signaling processing units 1050 and 1051. After that, when the first backup lightwave path is not the optimum backup lightwave path, the signaling processing units 1050 and 1051 create optimum backup lightwave path setting request information and transfer the information to the desired signaling demultiplexing units 1070 to 1073. Also, when the optimum standby lightwave path setting request information or the optimum standby lightwave path setting response information is received and the optimum standby lightwave path setting is possible, the lightwave paths SW1040 and 1041 and the ADMs 1020 to 1023 are provided.
To set an optimal standby lightwave path. Also, when receiving the optimal standby lightwave path setting request information, the information processing apparatus transfers the optimal standby lightwave path setting request response information to the desired signaling demultiplexing units 1070 to 1073.

When the connection of the optimal backup lightwave path is completed, the signaling processing units 1050 and 1051 send a path test request to the lightwave path test units 1710 and 1711. The lightwave path test units 1710 and 1711 monitor the path state by transmitting and receiving test signals using the optimal backup lightwave path. Thereafter, the lightwave path test units 1710 and 1711
Determines whether the optimal backup lightwave path can be used, and notifies the signaling processing units 1050 and 1051 of the result. Based on this, the signaling processing units 1050 and 1051 transfer the test result information of the optimal backup lightwave path to the desired signaling demultiplexing units 1070 to 1073.

The signaling processing units 1050, 10
51, the SW controller 1 receives the test result response information of the optimal backup lightwave path and, if the optimal backup lightwave path is available,
030, 1031 via the optical path SW 1040, 10
41, controlling the ADMs 1020 to 1023 to switch the communication path from the first backup lightwave path to the optimum backup lightwave path.

After that, the first backup lightwave path is transmitted to the signaling processing units 1050, 1150 through the path disconnection request / response information.
Reference numeral 051 denotes lightwave paths SW1040 and 1041 and ADMs 1020 to 1023 via SW controllers 1030 and 1031.
To release the path and restore the normal settings.

On the other hand, if the optimal backup lightwave path cannot be used, the signaling processing units 1050 and 1051 release the optimal backup lightwave path in the same manner as when releasing the first backup lightwave path.
Return to normal settings. The use of the stopped ET lightwave path can be resumed by returning the released network resource of the first backup lightwave path or the optimal backup lightwave path to the normal setting.

With the above-described apparatus configuration, two-stage failure recovery in the second embodiment can be realized.

FIG. 14 is a diagram showing another configuration example of the transmission devices 510, 520, 530, 540, and 550 for performing the second embodiment. It is assumed that the WDM transmission network to which the transmission device shown in FIG. 14 is applied has five wavelengths. The transmission device shown in FIG. 14 uses four wavelengths as lightwave paths for data transfer and one wavelength as a lightwave path for signaling path transfer in which a signaling channel is multiplexed. The transmission device shown in FIG. 14 transfers the signaling channel via another lightwave path without multiplexing the signaling channel on the main signal data lightwave path.

The transmission apparatus shown in FIG. 14 is different from the transmission apparatus shown in FIG.
To 1113 and the signaling channel demultiplexer 1120
Are newly added, and the signaling demultiplexing units 1070 to 1
073 is deleted. The operations of the signaling path multiplexing / demultiplexing units 1110 to 1113 and the signaling channel multiplexing / demultiplexing unit 1120 are the same as those shown in FIG. 7, and the operation of the common unit with the transmission apparatus shown in FIG. Is omitted.

In the transmission apparatus shown in FIG. 14, signaling transfer is performed on a lightwave path independent of the lightpath for the data path. In the network shown in FIG. 8A having the same configuration as that of FIG. 1A, lightwave paths 1210 and 1220 of the same wavelength group are respectively provided on the bidirectional fiber 501 between the transmission devices 520 and 530, and the transmission devices 520 and 530.
The transmission device 520 on the bidirectional fiber 502 via
When the distances are set between 530, that is, when the setting sections of the lightwave paths of the same wavelength group partially overlap,
As shown in FIG. 8B, the signaling channel 1230
By setting -1 to 1230-4, the transmission device 5
It becomes possible to exchange path switching information of the wavelength group among 10, 520, 530, and 540.

As a result, when the signaling channel is multiplexed on the lightwave path, the lightwave paths of the same wavelength group can be set only in the same section or completely different sections. However, in the transmission apparatus shown in FIG. Is eliminated and a flexible light wave path can be set.

With the above-described apparatus configuration, two-stage failure recovery, which is the failure recovery method of the second invention, can be realized, and by separating the lightwave path for signaling transfer and the lightwave path for data transfer. The light path setting of the WDM transmission network can be made flexible.

[0117]

Since the present invention is configured as described above, it has the following effects.

Since the failure is detected at the end of the lightwave path and the failure recovery process operates for each wavelength group to which the lightwave path belongs, even if the lightwave path of a specific wavelength suffers a failure, the lightwave path can be quickly restored from the failure. Can be recovered.

In addition, since switching is performed independently at each lightwave path at the end of the lightwave path, the path of the lightwave path after recovery from the failure is shorter than in a system in which the failure location is bypassed, and there is no need to limit the network scale.

Further, since fault detection is performed independently at the light wave path end for each light wave path, it is more accurate than the method of detecting a fault based on the amount of WDM signal light, and signal deterioration can be detected as a fault. Therefore, it is possible to efficiently recover from the failure.

Further, when a certain lightwave path suffers a fault, the path switching information is notified to the transmission device terminating the lightwave path of the same wavelength group through which the backup lightwave path passes. Therefore, when the notification is not received, that is, in a normal state without a failure, the ET can be accommodated using the network resources of the backup lightwave path, and the network can be used efficiently.

The first step of setting up a backup lightwave path using the failure recovery method, and the second step of setting an optimum backup lightwave path in consideration of network efficiency and the like and switching from the first backup lightwave path to the optimum backup lightwave path. In the case of the failure recovery method consisting of a stage process, if the backup lightwave path is not always optimal in terms of network efficiency and the like even if the failure recovery is performed in the first stage, the optimal backup lightwave path is selected. You can switch to it. As a result, for example,
In the first stage of disaster recovery, a backup lightwave path with a high recovery rate is selected to perform high-speed and high-speed failure recovery, and in the second stage, the network can be switched to the optimal backup lightwave path with high network efficiency. And the economics of the network can be compatible.

After setting the optimal backup lightwave path, a test of the optimal backup lightwave path is performed using the test signal, so that it is possible to accurately determine whether or not the optimal backup lightwave path can be used.

Further, by separating the lightwave path for data transfer and the lightwave path for signaling channel transfer,
Even if the setting sections of a plurality of lightwave paths of the same wavelength group partially overlap, information exchange using a signaling channel can be performed, so that the lightwave path setting of the network can be flexibly performed.

Further, by separating the lightwave path for data transfer and the lightwave path for signaling transfer, the bit rate and signal format of the lightwave path of the same wavelength group can be set freely.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating W for explaining a first failure recovery method according to the present invention;
FIG. 2 is a configuration diagram of a physical / lightwave path of a DM transmission network.

FIG. 2 is a failure recovery sequence diagram of a wavelength group of a wavelength λi in the first failure recovery method of the present invention.

FIG. 3 is a lightwave path network diagram of a wavelength group of a wavelength λi when a failure is recovered using the first failure recovery method of the present invention.

FIG. 4 is a failure recovery sequence diagram of a wavelength group of wavelength λj in the first failure recovery method of the present invention.

FIG. 5 is a lightwave path network diagram of a wavelength group of a wavelength λj when a failure is recovered using the first failure recovery method of the present invention.

FIG. 6 is a configuration diagram of a transmission device for describing Embodiment 2 of the present invention.

FIG. 7 is a configuration diagram of a transmission device for describing Embodiment 3 of the present invention.

FIG. 8 is a lightwave path network for data transfer and a lightwave path network for signaling channel or signaling path transfer.

FIG. 9 is a sequence diagram of the optimal standby lightwave path switching of the wavelength group of the wavelength λi in the second stage in the second two-stage failure recovery method of the present invention.

FIG. 10 is a time change of the lightwave path network in the optimum backup lightwave path switching sequence of the wavelength group of the wavelength λi in the second step in the second two-step failure recovery method of the present invention.

FIG. 11 is a sequence diagram of the optimal standby lightwave path switching of the wavelength group of the wavelength λj in the second stage in the second two-stage failure recovery method of the present invention.

FIG. 12 is a time change of the lightwave path network in the optimal backup lightwave path switching sequence of the wavelength group of the wavelength λj in the second step in the second two-step failure recovery method of the present invention.

FIG. 13 is a configuration diagram of a transmission apparatus according to a fifth embodiment of the present invention for realizing the second failure recovery method of the present invention.

FIG. 14 is a configuration diagram of a transmission apparatus according to a sixth embodiment of the present invention for realizing the second failure recovery method of the present invention.

FIG. 15 is a configuration diagram of a conventional transmission device used for a WDM transmission network.

FIG. 16 illustrates a physical / physical system for explaining a conventional failure recovery method.
It is an example of a lightwave path network.

FIG. 17 is a failure recovery sequence for describing a conventional failure recovery method in a WDM transmission network.

FIG. 18 is a diagram showing a fault recovery sequence for explaining a problem of the conventional fault recovery method when two lightwave paths are set in the WDM transmission network, and a lightwave path network after the fault recovery.

[Explanation of symbols]

101, 102, 201-i, 201-i + 1, 202
−i, 202-i + 1, 501-i, 501-i + 1,
502-i, 502-i + 1, 1001-1004
Input / output ports 201-1 to 201-5, 202-1 to 202-5, 5
01-1 to 501-5, 502-1 to 502-5 Bidirectional fiber 110, 111 Line SW 120, 121, 1070 to 1073 Signaling demultiplexing unit 130, 131, 1010 to 1013 Wavelength demultiplexing unit 140, 141 Failure detection Units 150, 1050, 1051 Signaling processing units 160, 1030, 1031 SW control units 210-250, 510-550 Transmission devices 260, 401, 402, 560-N, 561-N, 5
70-N, 571-N, 561-R, 561-RM, 5
71-R, 571-RM, 1210, 1220 Lightwave path 1230-1 to 1230-4 Signaling transfer lightwave path 310-1 to 310-4, 311-1, 320-1, 3
21-1 to 321-4, 410-1, 410-2, 41
1-1, 411-2, 420-1, 421-1, 430
-1,431-1,440-1,441-1,441-
2 Line path switching request information 330-1 to 330-4, 331-1, 340-1, 3
41-1 to 341-4, 450-1, 450-2, 45
1-1, 451-2, 460-1, 460-2, 461
-1, 461-2 Line path switching response information 610, 611, 620, 621 Path switching request information 630, 631, 640, 641 Path switching response information 1020 to 1023 ADM 1040, 1041 Lightwave path SW 1060 to 1063 Lightwave path termination processing Unit 1080 Preliminary lightwave path selection unit 1101 to 1113 Signaling path demultiplexing unit 1120 Signaling channel demultiplexing unit 1310, 1320 Optimal standby lightwave path setting request information 1330, 1340 Optimal standby lightwave path setting response information 1350, 1360 Preliminary lightwave path test result information 1370, 1380 Preliminary lightwave path test result response information 1710, 1711 Lightwave path test section

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04L 12/42

Claims (23)

(57) [Claims] 1. A communication path comprising a plurality of wavelength division multiplex transmission apparatuses (hereinafter referred to as transmission apparatuses) connected in a ring shape and including an arbitrary physical wavelength in an arbitrary section of the plurality of wavelength division multiplex transmission apparatuses. (Hereinafter, lightwave path) can be set bidirectionally, and a lightwave path used as a detour when a failure occurs in the working lightwave path with respect to a lightwave path normally used (hereinafter, working lightwave path) At least one or more backup lightwave paths (hereinafter referred to as “preliminary lightwave paths”) are defined. Normally, the network resources allocated to the backup lightwave paths are lightwave paths (hereinafter referred to as “ET”) for any additional or auxiliary use as necessary. It can be used as a network resource for setting up a lightwave path, and switches path switching control information for switching from the working lightwave path to the backup lightwave path when a failure occurs. In a failure recovery method based on path end switching in a wavelength division multiplexing transmission network in which a signaling channel to be transmitted or a signaling path multiplexing a signaling channel is set between transmission devices, each transmission device terminates a predetermined lightwave path. A lightwave path termination processing function for detecting a failure according to a signal reception state of the lightwave path, a path switching function for switching to the backup lightwave path when a failure of the working lightwave path is detected, and a path switching by the path switching function. Has a signaling processing function of exchanging control information for the signaling channel using the signaling channel, and when a failure occurs in the working lightwave path, detects a failure of the working lightwave path in which the failure has occurred (hereinafter, a failure lightwave path). Terminating transmission equipment (hereinafter referred to as failure detection transmission equipment) is used from multiple standby lightwave paths. Select capacity of one or a plurality of preliminary light wave path, other transmission apparatus serving as a termination point of failure optical path (hereinafter disorders optical path opposing transmission device), stop per use the pre light wave path setting <br/> and available to the transmission device at both ends of the ET light wave path required (hereinafter ET light wave path terminated transmission apparatus)
Notifies the path switching request information including the pre light wave path information selected Te, ET light wave path terminated transmission device stops using the ET light wave path when receiving the path switching request information, the fault light wave path opposing transmission device Receives the path switch request information.
, The selected standby lightwave path is determined as one, and the path is switched.
After executing the determined preliminary light wave path information including path switching
Switching request response information between the ET lightwave path terminal transmission device and the
The ET lightwave path terminating transmission device receives the path switching request response information.
In response to this, refer to the determined preliminary lightwave path information and set
Backup lightwave path and ET lightwave path terminated by the own transmission equipment
If they share network resources,
Work resources are allocated to the determined backup lightwave path and ET light
Restarting the use of the optical path, and receiving the path switching response information, the failure detection transmission device recovers the failure on a lightwave path unit basis by performing path switching to the backup lightwave path described in the path switching response information. Recovery method by switching path ends in a wavelength division multiplexing transmission network. 2. The fault recovery method according to claim 1, wherein all of the working lightwave paths are constituted by a single physical wavelength, and the spare lightwave path corresponding thereto is constituted by a working lightwave path. A wavelength group composed of a single physical wavelength that is the same as or different from the physical wavelength to be formed, and formed by one or more limited physical wavelengths used in the working lightwave path and a plurality of backup lightwave paths corresponding thereto. A fault recovery method by switching path ends in a wavelength division multiplexing transmission network, wherein fault recovery of faulty lightwave paths is executed in parallel by wavelength group units. 3. The failure recovery method according to claim 1, wherein a protection light path is provided to the working lightwave path by a different path from the working lightwave path. A failure recovery method by switching path ends in a wavelength division multiplexing transmission network, wherein a physical wavelength different from that of the working lightwave path is provided, or both are provided according to the situation. 4. The fault recovery system according to claim 1, wherein a plurality of backup lightwave paths for the working lightwave path are provided when a plurality of protection lightwave paths exist for the working lightwave path. In the wavelength division multiplexing transmission network, the selection order is set in advance for the lightwave path, and the fault detection transmission device sequentially selects a backup lightwave path for performing fault recovery of the faulty lightwave path according to the order. Failure recovery method by path end switching. 5. The fault recovery method according to claim 4, wherein the order of selection of the backup lightwave path is set by the number of hops, the transmission distance, the efficiency of the network resources, or the fault recovery probability. A failure recovery method by switching a path end in a wavelength division multiplexing transmission network. 6. A failure recovery method by switching a path end in a wavelength division multiplexing transmission network according to claim 4, wherein a bidirectional failure occurs in a predetermined lightwave path, and a plurality of terminations of the failure lightwave path are generated. If one or a plurality of backup lightwave path information notified from each of the failure detection transmission devices by the path setting request information is different, the transmission device terminating the failure lightwave path is one of the notified backup lightwave path and the selected backup lightwave path. 1. A failure recovery method by switching a path end in a wavelength division multiplexing transmission network, wherein one standby lightwave path is determined based on a predetermined order. 7. The failure recovery system according to claim 4, wherein the network resources allocated to the backup lightwave path of the predetermined working lightwave path are different from those in the wavelength division multiplexing transmission network. The path switching request information and the path switching response information are used as a backup lightwave path of the working lightwave path, and some or all of the network resources of the backup lightwave path used for switching the failed lightwave path are used as the backup lightwave path of the own. The transmission device at both ends of the working lightwave path shared as part or all of the network resources (hereinafter referred to as a backup lightwave path shared transmission device) is also notified, and the backup lightwave path shared transmission device transmits the backup lightwave path to its own transmission device. Characterized in that the active light path is terminated from the backup light path candidate and the order of the backup light path is dynamically changed. Failure recovery method according to the path end switching in division multiplex transmission networks. 8. The fault recovery system according to claim 1, wherein the transmission device that terminates a certain lightwave path detects a lightwave path termination processing function and a fault in the working lightwave path. A plurality of backup lightwave paths of a faulty lightwave path can be set as a path switching function for switching to the backup lightwave path at a time, and a signaling processing function adds control information for path switching and a path for more optimal lightwave path setting. The setting information can be exchanged using a signaling channel, and when a failure of a predetermined working lightwave path is detected, the failure detection transmission device switches from the failed lightwave path to the backup lightwave path, recovers from the failure, and then switches. A standby lightwave path (hereinafter, referred to as a first standby lightwave path) and a standby lightwave path determined to be optimal as a standby lightwave path (hereinafter, referred to as an optimal standby lightpath). When the ET is different from the ET lightwave path terminating transmission device and the opposite lightwave path opposite transmission device that uses a part or all of the network resources of the optimum backup lightwave path, the transmission of the optimum backup lightwave path is requested. The lightwave path terminal transmission device stops using the ET lightwave path when receiving the optimum lightwave path setting request information, and the faulty lightwave path opposite transmission device receives the optimum backup lightwave path setting request information, and After setting the transmission and reception of the path to be possible, the ET lightwave path terminal transmission device and the failure detection transmission device are notified of the optimum protection lightwave path setting request response information including the result of setting the optimum protection lightwave path, and the ET lightwave When the path terminating transmission device receives the optimum path setting request response information, the optimum standby light path is set up with reference to the setting result of the optimum standby light wave path. If it is set, the network resource allocated to the ET lightwave path is allocated to the optimal backup lightwave path. If the optimal backup lightwave path is not set, the use of the ET lightwave path is resumed, When the failure detection transmission device that has received the lightwave path setting request response information has the optimal protection lightwave path set, the failure detection transmission device bidirectionally switches from the first protection lightwave path to the optimum protection lightwave path. A failure recovery method by switching path ends in a wavelength division multiplexing transmission network, wherein a lightwave path opposite transmission device releases a first backup lightwave path. 9. A failure recovery system based on path switching in a wavelength division multiplexing transmission network according to claim 8, wherein when a failure of a predetermined working lightwave path is detected, the failure detection transmission device transmits an optimum protection lightwave path setting request. The ET lightwave path terminating transmission device that has stopped using the ET lightwave path at the time of setting the first spare lightwave path is also notified of the optimal standby lightwave path setting response. A failure recovery method by switching path ends in a wavelength division multiplexing transmission network, which recognizes that a path is released and resumes use of a stopped ET lightwave path. 10. The fault recovery system according to claim 8, wherein the transmission device sets an optimal backup lightwave path and uses the test signal to set the optimal backup lightwave path. The fault detection transmission device and the faulty light path opposing transmission device establish an optimum backup light wave path in both directions, and then transmit the test signal using the optimum backup light wave path. The transmission / reception of each other determines whether the optimal backup lightwave path can be used, and stops the use of the test signal when the failure detection transmission device and the failure lightwave path opposite transmission device both determine that the optimal backup lightwave path can be used. Switching from the first standby lightwave path to the optimum standby lightwave path, Disaster recovery method. 11. The fault recovery system according to claim 8, wherein all of the working lightwave paths are constituted by a single physical wavelength, and a spare for the working lightwave path is provided. The lightwave path is composed of a single physical wavelength that is the same as or different from the physical wavelength that constitutes the working lightwave path, and one or more limited physical resources used in the working lightwave path and a plurality of backup lightwave paths corresponding thereto. A failure recovery method by switching path ends in a wavelength division multiplexing transmission network, wherein failure recovery is performed in parallel for each wavelength group by forming a wavelength group formed by wavelengths. 12. The fault recovery system according to claim 8, wherein the first and second protection lightwave paths are provided for the working lightwave path. A fault recovery method by switching a path end in a wavelength division multiplexing transmission network, wherein the path is provided by a different path from the working lightwave path, by a different physical wavelength from the working lightwave path, or by combining the two depending on the situation. 13. A failure recovery system by path switching in a wavelength division multiplexing transmission network according to any one of claims 8 to 12, wherein, when a plurality of backup lightwave paths of a certain working lightwave path exist, the protection lightpaths are used. 9. The selection order is set in advance for the backup lightwave path, and the fault detection transmission device selects the first backup lightwave path and the optimum backup lightwave path according to claim 8 according to the selection order. Failure recovery method by switching path ends in transmission networks. 14. The fault recovery method according to claim 13, wherein the selection order of the first backup lightwave path and the optimum protection lightwave path is the number of hops, the transmission distance, or the efficiency of network resources. A failure recovery method by switching path ends in a wavelength division multiplexing transmission network, wherein the failure recovery method is set according to use or failure recovery probability. 15. A failure recovery method by switching a path end in a wavelength division multiplexing transmission network according to claim 13 or 14, wherein a bidirectional failure occurs in a certain lightwave path, and a plurality of terminals terminating the failed lightwave path. If one or a plurality of backup lightwave path information notified from each of the failure detection transmission devices by the path setting request information is different, or if the optimum protection lightpath information notified by the optimum protection lightwave path setting request information is different, the backup lightwave path is changed. Information or the optimal backup lightwave path information is transmitted to the transmission device that has been notified of the backup lightwave path information or optimal backup lightwave path information and the predetermined order from the backup lightwave path or optimal backup lightwave path selected by the own transmission device. Path end in a wavelength division multiplexing transmission network characterized in that the path end is determined based on one. Disaster recovery system based on exchange. 16. A failure recovery method by switching a path end in a wavelength division multiplexing transmission network according to any one of claims 13 to 15, wherein a network resource allocated to a protection lightwave path of a certain working lightwave path is another network lightwave. The path switching request information, the path switching response information, the optimum standby light path test result information, and the optimum standby light path test response information that are used as a backup light path of the working light path are used as a spare path used as a detour of the fault light path. The transmission device at both ends of the working lightwave path that shares a part of the lightwave path as a backup lightwave path (hereinafter referred to as a backup lightwave path shared transmission device) is also notified, and the backup lightwave path in which the backup lightwave path shared transmission device is used is notified. It is deleted from the first backup lightwave path candidate and the optimum backup lightwave path candidate of the working lightwave path terminated by the own transmission device, and the order of the backup lightwave path is changed. Failure recovery method according to the path end switching in wavelength division multiplexing transmission network, characterized by dynamically changing the. 17. A transmission apparatus comprising a failure recovery system by switching path ends in a wavelength division multiplexing transmission network according to claim 1 or 8, wherein the wavelength division multiplexing signal is separated into lightwave paths for each wavelength. A wavelength division multiplexing / demultiplexing unit that multiplexes a lightwave path to be transmitted and a lightwave path newly inserted from the own transmission device out of the lightwave paths, and the lightwave path separated by the wavelength division multiplexing / demultiplexing unit is transferred.
The lightwave path terminated by the own transmission device is taken into the own transmission device, the lightwave path not terminated by the own transmission device is transferred to the wavelength division multiplexer, and the lightwave path generated by the own transmission device is subjected to wavelength demultiplexing. An ADM unit for transferring the lightwave path to a unit, a lightwave path switch unit for switching a lightwave path captured and transferred by the ADM unit, or a lightwave path generated by the own transmission device; and a transfer from the lightwave path switch unit. A lightwave path termination processing unit for detecting a failure of the lightwave path terminated by the own transmission device and terminating the lightwave path generated by the own transmission device, and a lightwave path transferred from the lightwave path termination processing unit A signaling multiplexing / demultiplexing unit for multiplexing a signaling channel into a signaling channel or a lightwave path generated by the own transmission apparatus, and fault information from the lightwave path termination processing unit. Receive or
Receives information transferred from another transmission device by a signaling channel separated by the signaling demultiplexing unit, generates information for path switching using a signaling processing function, and sends the information to a signaling demultiplexing unit. A backup lightwave path for a fault lightwave path is transferred to another transmission apparatus through a signaling channel, and the path and wavelength of the lightwave path passing through the own transmission apparatus are changed by controlling the ADM section and the lightwave path switch section. A signaling processing unit that performs switching to the, and when receiving a backup lightwave path selection request from the signaling processing unit, selects one or more backup lightwave path candidates, and also includes a plurality of backup lightwave path information from the signaling processing unit. Upon receiving the backup light path selection decision request, one of the plurality of backup light paths is selected. And a backup lightwave path selecting unit for notifying the signaling processing unit. 18. A transmission apparatus comprising a failure recovery system by path end switching in a wavelength division multiplex transmission network according to claim 1 or 8, wherein signaling is performed from a light wave path transferred from the light wave path termination processing unit. A signaling multiplexing / demultiplexing unit that multiplexes a signaling channel into a channel or a lightwave path generated by its own transmission device; and a lightwave path for signaling path transfer and a lightwave path for data transfer from the input wavelength-division multiplexed signal. Signaling path multiplexing for transferring a lightwave path for data transfer as an input signal to the wavelength division multiplexing / demultiplexing unit, and multiplexing the lightwave path for signaling path generation generated by the own transmission apparatus with the WDM signal transferred from the wavelength division multiplexing / demultiplexing unit A separating unit; and a signaling path transfer transferred from the signaling path demultiplexing unit. Terminates the lightwave path for use, separates the signaling channel to be processed from the signaling path, transmits the signaling channel that is not processed, and remultiplexes these with the signaling channel that has been subjected to signaling processing in its own transmission device to transfer the signaling path. A signaling path terminating unit that generates a lightwave path for use and then transfers to the signaling path demultiplexing unit, and the lightwave path separated by the wavelength demultiplexing unit is transferred,
The lightwave path terminated by the own transmission device is taken into the own transmission device, the lightwave path not terminated by the own transmission device is transferred to the wavelength division multiplexer, and the lightwave path generated by the own transmission device is subjected to wavelength demultiplexing. An ADM unit for transferring the lightwave path to a unit, a lightwave path switch unit for switching a lightwave path captured and transferred by the ADM unit, or a lightwave path generated by the own transmission device; and a transfer from the lightwave path switch unit. A lightwave path termination processing unit that detects a failure of the lightwave path terminated by the own transmission device and terminates the lightwave path generated by the own transmission device, and receives failure information from the lightwave path termination processing unit or ,
Receives information transferred from another transmission device by a signaling channel separated by the signaling termination processing unit, generates information for path switching using a signaling processing function, and sends the information to the signaling termination processing unit. A backup lightwave path for a fault lightwave path is transferred to another transmission apparatus through a signaling channel, and the path and wavelength of the lightwave path passing through the own transmission apparatus are changed by controlling the ADM section and the lightwave path switch section. A signaling processing unit that performs switching to the, and when receiving a backup lightwave path selection request from the signaling processing unit, selects one or more backup lightwave path candidates, and also includes a plurality of backup lightwave path information from the signaling processing unit. Upon receiving the backup light path selection decision request, one of the plurality of backup light paths is selected. And a backup lightwave path selecting unit for notifying the signaling processing unit. 19. The transmission device according to claim 17, wherein the signaling processing unit is arranged for each wavelength group according to claim 2 or 11 and executes a failure recovery for each wavelength group. A transmission device characterized by the above-mentioned. 20. The transmission apparatus according to claim 17, wherein a test signal of the optimal backup lightwave path according to claim 8 is transmitted and received under the control of a signaling processing unit. A transmission apparatus comprising: a lightwave path test unit that performs a test on the signal processing unit and notifies a result of the test to a signaling processing unit. In the transmission apparatus 21. The method of claim 20 wherein the light wave path test unit is arranged for each wavelength group according to claim 2 or claim 11 is terminated at its own transmission equipment, fault recovery for each wavelength group A transmission device characterized by performing: 22. The transmission apparatus according to claim 17, wherein the backup lightwave path selection unit has backup lightwave path information for each wavelength group, and determines a selection order of the backup lightwave paths by the number of hops or the number of hops. It is set in accordance with the transmission distance or the efficient use of network resources or the probability of failure recovery, and notifies one or a plurality of higher-order backup lightwave paths in a higher order in response to a request for selection of a backup lightwave path by the signaling processor. Transmission equipment. 23. The transmission apparatus according to claim 22, wherein the backup lightwave path selection unit responds to the backup lightwave path selection determination request notified from the signaling processing unit based on a predetermined order from a plurality of backup lightwave path candidates. A backup lightwave path determined as one.