JPH08125636A - Method for wavelength multiplex protection and its transmitter - Google Patents

Abstract

PURPOSE: To obtain a method of quick and sure protection in a wavelength multiplex transmission line by transferring signals of all wavelengths including signals of other wavelength sent through an active transmission line through wavelength multiplex to a standby transmission line when an error is detected in the signal. CONSTITUTION: When a fault takes place in an E/O converter, a monitor circuit 21-1 informs occurrence of fault to a control circuit 25-1. The control circuit 25-1 controls a selector 23-1 and selects an output of an ODE converter 31-1-2 in place of an output of an O/E converter 31-1-1. Furthermore, the control circuit 25-1 gives a changeover instruction to other control circuits 25-2, 25-3. The control circuits 25-2, 25-3 receiving the changeover instruction select the reception of the signal from a standby transmission line 12. Through the operation above, even when an error is detected from a signal of a single wavelength only in the active wavelength multiplex transmission line 10, or an error takes place simultaneously in signals of one wavelength or over, the reception of signals of all wavelengths from the standby transmission line 12 is easily selected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission line protection method and a transmission device used for wavelength division multiplexing transmission.

[0002]

2. Description of the Related Art In a conventional transmission line, a single transmission line uses only one wavelength to transmit a signal. Then, transmission lines are doubled, one is used as a working side and the other is used as a spare, and transmission and reception are normally performed using the working transmission line. In addition, such a network has a function of recovering from a failure that has occurred by switching to the backup transmission path when a failure occurs in the working transmission path. This operation is called a protection operation.

For example, in the 1 + 1 protection system, as shown in FIG. 2, a working transmission line 10 and a backup transmission line 1 are provided.
A pair of two are provided, the transmitting side node 1 transmits the same signal as the working side and the spare side (bridge), and the two-input / one-output selector 23 provided at the receiving side node 2 selects one of the working highway 12-4 and the spare highway 12-5. Select one.

The above selection method will be described below. The receiving side node 2 is provided with monitoring circuits 21-1 and 22-2 for detecting a failure in the working transmission path and the protection transmission path, and the presence or absence of a failure in each transmission path is determined based on the result of monitoring by the monitoring circuit. For example, when the monitoring circuit 21-1 detects a failure in the working transmission line 10, the monitoring circuit 21-1 notifies the control circuit 25 that the failure is detected. Based on this, the control circuit 25
Controls the selector 23 to select the spare highway 12-5 instead of the active highway 12-4 to recover from the failure.

Further, in the 1: N protection system (N is a natural number), N working transmission lines 10-1 to 10-1 are provided as shown in FIG.
10-N shares one spare transmission line 10-0. In this method, the receiving side of each transmission line monitors the state of the transmission line,
When a failure is detected in one working transmission line, the signal transmitted using the working transmission line is transferred to the protection transmission line. Further, when a failure is detected in a plurality of working transmission lines, the signals transmitted to the working transmission lines with higher priority are moved to the backup transmission lines according to the priorities assigned to the N working transmission lines in advance.

The 1: N protection operation is realized by the nodes 1-1 and 1-2 at both ends of the transmission line exchanging control signals. 1: Outline of N protection operation
The monitoring circuit 22-1 of the node 1-2 is the working transmission line 10-1.
The case where the occurrence of a failure is detected will be described as an example.

First, in the initial state, all N working transmission lines are normal, and each of the selectors 23-1 to 23-N, 2 is
It is assumed that the current transmission lines are selected in 4-1 to 24-N.

Next, it is assumed that the monitoring circuit 22-1 of the node 1-2 detects a failure in the working transmission line 10-1. The monitoring circuit 22-1 transmits the failure detection to the control circuit 25-2.
Since the fact that a failure has occurred in the working transmission line 10-1 is transmitted to the opposite node 1-1 by a control signal, the control circuit 25-
2 instructs the control signal insertion circuit 34-2 to generate a control signal for transmitting the failure occurrence. For the control signal transmission, the overhead portion of the signal transmitted on the backup transmission lines 10-0 and 11-0 may be used.

The monitoring circuit 21-0 of the node 1-1 receives the control signal and transmits it to the control circuit 25-1. The control circuit 25-1 controls the selector 23-0 and transmits the signal of the highway 13-1, which has been transmitted using the working transmission path 10-1 until now, using the backup transmission path 10-0. In addition, the control signal insertion circuit 34-1 is instructed to output a control signal that notifies the node 1-2 that the active transmission path 10-1 has been switched to the backup transmission path 10-0.

The monitoring circuit 22-0 of the node 1-2 receives the control signal and transmits it to the control circuit 25-2. The control circuit 25-2 controls the selector 24-1 to switch the signal previously received from the working transmission line 10-1 to be received from the backup transmission line 10-0. Further, the selector 24-0 is controlled so that the signal of the highway 16-1 which has been transmitted using the working transmission path 11-1 up to now is transmitted using the protection transmission path 11-0. In addition, the control signal insertion circuit 34-2 is instructed to output a control signal that notifies the node 1-1 that the active transmission path 11-1 has been switched to the backup transmission path 11-0.

The monitoring circuit 21-0 of the node 1-1 receives the control signal and transmits it to the control circuit 25-1. The control circuit 25-1 controls the selector 23-1 to switch the signal which has been received from the working transmission path 11-1 up to now to the protection transmission path 11-0.

The switching process is completed as described above.

The configurations when the 1 + 1 and 1: N protection methods are applied to the wavelength division multiplexing transmission line are as shown in FIGS. 4 and 5, the number of wavelengths to be multiplexed and transmitted is 3 (λ1 to λ3). For wavelength division multiplex transmission, each node converts the electrical signal into an optical signal having a wavelength of λ1 to λ3, and E / O converters 30-1 to 30-3,
And O / E converters 31-1 to 31-31 that perform the inverse conversion thereof
-3 is used. The optical output signals of the E / O converters 30-1 to 30-3 are multiplexed by the wavelength multiplexer 32 and output to the transmission line.

The protection operation can be realized by the same processing as in the case of a single wavelength. That is, the monitoring circuit 21 is provided for each wavelength to detect a failure for each wavelength. Then, the signal of the wavelength at which the failure is detected is transferred to the backup transmission line.

For example, when the wavelength division multiplex transmission line 10 is disconnected in FIG. 4, the signals of all the wavelengths transmitted to the transmission line are damaged, so that the signals of all the wavelengths should be transferred to the backup transmission line. Become. Further, when a failure occurs only in a single wavelength of one working transmission line (when a transmission circuit fails, etc.), only the signal of that wavelength is transferred to the backup transmission line.

The same process is performed when the 1: N protection method is used for the wavelength division multiplexing transmission line (FIG. 5).
In FIG. 5, only the direction from the nodes 1-1 to 1-2 is shown. Also, the control signal insertion circuit shown in the 1: N protection method (FIG. 3) is omitted. Space switches 35 and 36 are used instead of the selectors.

In FIG. 5, when the working transmission line 10-1 is disconnected, the monitoring circuits 22-1-1, 22-2-1 and 22--22.
3-1 detects the occurrence of a failure and notifies the control circuit 25-1-
2, 25-2-2, 25-3-2. Less than,
The control circuit 25-1-2, 25-2-2, 25-3- is operated in the same procedure as the 1: N protection method (FIG. 4).
2 is a space switch 36-1-2, 36-2-2, 36-
3-2 are respectively controlled to control circuits 25-1-1 and 25-2.
-1,25-3-1 are space switches 35-1-1,35
2-1 and 35-3-1 are controlled respectively, and the working transmission line 10
The signal transmitted using -1 is switched to the backup transmission line 10-0.

Further, when a failure occurs only in a signal of a single wavelength, only the failed signal occurs in the backup transmission line 10-
Use 0 to transmit.

That is, in the conventional example, a monitoring circuit, a control circuit, and a space switch are provided for each wavelength, and 1: N is provided for each wavelength.
Apply protection method to recover from failure.

Hereinafter, for convenience, the protection method used for the wavelength division multiplexing transmission line is referred to as a wavelength division multiplexing protection method. Further, the (1 + 1) protection method used for the wavelength multiplexing transmission line is called a wavelength multiplexing (1 + 1) protection method. Further, the 1: N protection method used for the wavelength multiplexing transmission line is referred to as the wavelength multiplexing 1: N protection method.

[0021]

(1 + 1) Consider a case where a repeater using an optical fiber amplifier (hereinafter referred to as a 1R repeater) is used in a protection wavelength division multiplex transmission line. The structure of the transmission line in this case is shown in FIG. The 1R repeater 37 can simultaneously amplify input signals of a plurality of wavelengths.

When a failure occurs in the O / E converter 30-1 having the wavelength λ1 in the transmission line (three-wavelength multiplexing) having the configuration shown in FIG. 6A, only the signal having the wavelength λ1 is used as the backup transmission line 10-. Will be moved to zero.

However, in this case, since the signal of the wavelength λ1 is disturbed, the signal power of the wavelength λ1 input to the 1R repeater 37-1 changes. At this time, changes in the signal power of the wavelength λ1 input to the 1R repeater 37-1 also affect other wavelengths (λ2, λ3).
That is, the balance of the input signal power of the 1R repeater is lost, so that the output signal power of the 1R repeater 37-1 changes. As a result, a change occurs in the received signal power of the wavelengths λ2 and λ3 at the receiving node (1-2),
It is known that reception becomes impossible.

That is, as the total input power of the 1R repeater changes, the operating point of the 1R repeater changes. 1
When the operating point of the R repeater changes, at least the following two effects are given to the transmission characteristics. First of all, the wavelengths λ2 and λ3
, The gain changes, and the output of each wavelength of the 1R repeater changes. In a transmission line in which 1R repeaters are connected in multiple stages, this is accumulated, and the signal powers of the wavelengths λ2 and λ3 in the vicinity of the receiving side node deviate greatly from the normal state. As a result,
The influence of non-linear effects (self-phase modulation effect and cross-phase modulation effect) in the optical fiber changes, and the received waveform distortion increases. This causes an increase in bit error rate. In the worst case, LOF (Loss of Frame) may occur.

The second effect is A generated from the 1R repeater.
This is because the spectrum of SE (Amplified Spontaneous Emission) noise light changes, and the reception SN ratio of signals of wavelengths λ2 and λ3 changes in multistage relay transmission. This change also causes deterioration of the code error rate.

That is, in the wavelength division multiplexing transmission line using the 1R repeater, even if a failure occurs in a signal of one wavelength among the signals of a plurality of wavelengths that are wavelength-multiplexed, as a result, signals of all wavelengths are Transmission becomes impossible.

In order to prevent such a situation, a method of providing a 1R repeater for each wavelength can be considered (FIG. 6).
(B)). However, this system has a drawback that the cost becomes high because it is necessary to provide a 1R repeater for each wavelength.

When the protection operation is performed independently for each wavelength, the signal of the wavelength (referred to as λ1) in which the fault occurs in the working transmission line 10 is first transferred to the backup transmission line 12,
After that, the 1R repeater affects the signals of other wavelengths,
The monitoring circuit 21-1 of the receiving side node 2 detects this and switches to the backup transmission line for each wavelength. However, in the 1R repeater, the unstable state continues in the transmission system while the reception side node 2 detects that one wavelength has affected another wavelength. Moreover, it is impossible to realize a quick recovery process by the method.

Alternatively, it is possible that a wavelength multiplexer for wavelength-multiplexing a plurality of wavelength signals or a wavelength separator for separating a wavelength-multiplexed signal into wavelength units is broken by one wavelength. In this case, in order to repair or replace the failed wavelength multiplexer or wavelength demultiplexer, it is necessary to move all wavelength-multiplexed signals to the backup transmission line.

Therefore, it is necessary to transfer not only the signal of the wavelength in which the failure has occurred but also the signals of all the wavelengths wavelength-multiplexed in the transmission line to the backup transmission line all at once.

In addition to the problems, there are the following problems. Wavelength multiplex 1: N in case of N protection system, N
The number of wavelengths used for the current transmission line of a book is not always the same. Therefore, when the 1R repeater is used for the working transmission line and the protection transmission line which implement the wavelength division multiplexing 1: N protection method, the 1R repeater of the protection transmission line is used for the working transmission line using the protection transmission line for the reason described above. It is necessary to adjust according to the number of wavelengths. Therefore, also in this case, an object of the present invention, which leads to an increase in cost and an increase in recovery time, is to provide a rapid and reliable protection method in a wavelength division multiplexing transmission line.

[0032]

The object is realized by means for detecting a failure for each signal of each wavelength and means for simultaneously switching a signal wavelength-multiplexed and transmitted on one working transmission line to a backup transmission line. It

For the unused signal of the wavelength-multiplexed signals, signal generating means having a specific pattern for transmitting the fact that the signal is unused to the receiving side node is used.

[0034]

In the present invention, the failure detecting means is provided for each wavelength.
First, in the case of wavelength division multiplexing (1 + 1) protection system,
In the receiving side node, when the failure detecting means detects a failure in a signal of a certain wavelength of one working transmission path, by moving signals of all wavelengths sharing the working transmission path to the backup transmission path,
Switching to the backup transmission line can be completed. Even if a signal of one wavelength fails, signals of all wavelengths are transferred to the backup transmission line, so that a quick protection operation can be realized.

Further, in the case of the wavelength division multiplexing 1: N protection system, if the failure detecting means detects a failure in a signal of a certain wavelength of one working transmission line at the receiving side node, all wavelengths sharing the working transmission line are detected. By switching the signal of 1 to the backup transmission line, the switching to the backup transmission line can be completed quickly.

Next, in the case of the wavelength division multiplexing 1: N protection system, the processing method when the number of wavelengths used in the working transmission line is smaller than the number of wavelengths of other working transmission lines will be described below.

That is, the number of wavelengths used in advance in the backup transmission line is the same as the number of wavelengths used in the active transmission line having the largest number of used wavelengths (k: k is a natural number) among the active transmission lines sharing the backup transmission line. Leave. When a signal on the working transmission line with a small number of wavelengths is transferred to the backup transmission line, for wavelengths larger than the number of wavelengths (j: j is a natural number, j <k) of the working transmission line transferred to the backup transmission line, , (K−j) signal generators are connected.

The number of wavelengths of the spare transmission line can be made constant regardless of the number of wavelengths of the working transmission line using the spare transmission line by the signal and the signal generating means using the working transmission line. There is no need to adjust the 1R repeater. Therefore, a quick protection operation becomes possible.

Alternatively, if the number of wavelengths used in the backup transmission line and the N active transmission lines is always the same (k) and only j (j <k) wavelengths are used in the active transmission line, It is also possible to connect a signal generating means to the remaining wavelengths (k-j). When the signal of the transmission line is transferred to the backup transmission line, the signal generated by the signal generating means is also transferred to the backup transmission line together with j signals.

In this case, if a specific pattern is inserted into the signal generated by the signal generating means, the receiving side can judge that the signal having the above pattern is unused and can be easily discarded.

[0041]

EXAMPLE A first example of the present invention is a wavelength division multiplexing (1+
1) Regarding protection method. The target network configuration of this embodiment is shown in FIG. In the wavelength division multiplexing transmission line shown in FIG. 6A, three wavelengths λ1, λ2, and λ3 are used, and signals are transmitted by the wavelength division multiplexing method. In addition, between the node 1 and the node 2, 1R relays 37-1, 37-
2 is connected.

The structure of the transmitting side node 1 used in such a network is shown in FIG. 6 (a). The node 1 is an E / O converter 30-1-1 for converting an input electric signal into an optical signal,
30-1-2 (wavelength λ1), E / O converter 30-2-
1, 30-2-2 (wavelength λ2), E / O converter 30-3-
1, 30-3-2 (wavelength λ3), a wavelength multiplexer 32-for wavelength-multiplexing the optical output (wavelengths λ1 to λ3) of each E / O converter.
1, a wavelength multiplexer 32-2.

Next, FIG. 1 shows the configuration of the receiving side node 2 used in this embodiment. The node 2 is a wavelength demultiplexer 33-1 that demultiplexes the wavelength-multiplexed input optical signal into wavelength units, a wavelength demultiplexer 33-2, and O / that converts the input optical signal into an electrical signal.
E converters 31-1-1, 31-1-2 (wavelength λ1), O
/ E converter 31-2-1, 31-2-2 (wavelength λ2), O
/ E converters 31-3-1 and 31-3-2 (wavelength λ3),
Monitoring circuits 21-1 to 21 for detecting a failure state of a received signal
-3, the monitoring circuits 22-1 to 22-3, and the control circuit 25 that determines whether to select one of the signal received from the working transmission line 10 and the signal received from the standby transmission line 12 according to the information from each monitoring circuit. 1 to 25-3, and selectors 23-1 to 23-3 which select and output one of the input signals of the two systems according to the instruction of each control circuit. Control circuit 25
-1 to 25-3 are connected by a bus 17.

As an initial state in this configuration, the selectors 23-1 to 23-3 of the receiving-side node 2 have the working transmission line 1
It is assumed that the signal received from 0 is selected. That is, each of the control circuits 25-1 to 25-3 includes the selector 23.
It instructs -1 to 23-3 to select the signal arriving from the working transmission line 12.

With this configuration, the E / O converter 30 of the node 1
The processing when a failure occurs at 1-1 (wavelength λ1) is shown below. When a failure occurs in the E / O converter 30-1-1, the monitoring circuit 21-1 of the node 2 eventually detects the failure. The monitoring circuit 21-1 notifies the control circuit 25-1 that a failure has occurred. The control circuit 25-1 recognizes that a failure has occurred in the signal of the wavelength λ1 on the working transmission line 10,
The selector 23-1 is controlled to control the O / E converter 31-1-1.
The output of the O / E converter 31-1-2 is selected instead of the output of.

The control circuit 25-1 is the other control circuit 2
A switching command is issued to 5-2 and 25-3. The switching command is transmitted on the bus 17 and arrives at the control circuits 25-2 and 25-3. Control circuits 25-2 and 25 that have received the switching command
-3 switches to select a signal to be received from the backup transmission line 12 by controlling the selectors 23-2 and 23-3, respectively.

By this operation, the current wavelength division multiplexing transmission line 1
At 0, even if a failure is detected only in a signal of a single wavelength, switching is performed so that signals of all wavelengths are received from the backup transmission line 12. Similarly, even if a failure occurs simultaneously in one or more wavelength signals wavelength-multiplexed on the working transmission line 10, it is possible to easily switch to receive all wavelength signals from the backup transmission line 12.

The control method in this embodiment can be applied to the case shown in FIG. In FIG. 7, optical signal outputs of three different transmission devices 3-1 to 3-3 (wavelengths λ1, λ2, λ, respectively) are shown.
3) is input to the wavelength multiplexers 32-1 and 32-2. The outputs of the respective wavelength multiplexers 32-1 and 32-2 pass through the working transmission line 10 and the backup transmission line 12, respectively, and the 1R repeater 37-
1, 37-2, and wavelength separators 33-1 and 33-2
Respectively. The wavelength demultiplexers 33-1 and 33-2 distribute the optical signal for each wavelength and output the optical signals to the transmission devices 2-1 to 2-3. The configurations of the transmission devices 2-1 to 2-3 are the same as the configuration of the node 2 in FIG. In FIG. 7, each transmission device 2-1 to 2-1
The 2-3 control circuits 25-1 to 25-3 are connected by a bus 17. Even when one control circuit detects a failure in the signal arriving from the working transmission line, the control circuit sends the control signal to the control circuit of another transmitting device by using the bus 17, so that all the transmitting devices are in the working transmission line. 10 to backup transmission line 12
Switch to.

In this embodiment, each control circuit exchanges control signals, so that even if a fault is detected in a single wavelength signal among a plurality of wavelength-multiplexed wavelength signals, all wavelength signals are currently used. The transmission line 10 was switched to the backup transmission line 12. This operation can also be realized by a method of transmitting the output of each monitoring circuit to all control circuits. That is,
In FIG. 1, each monitoring circuit 21-1 to 21-3, 22-1 to 2
By connecting the output of 2-3 to all the control circuits 25-1 to 25-3, the control circuits 25-1 to 25-3 can know the monitoring results of all the monitoring circuits.

In this case, the processing when the monitoring circuit 21-1 detects the occurrence of a failure will be described below. Monitoring circuit 21-1
After detecting the failure, notifies all the control circuits of the failure occurrence. The control circuits 25-1, 25-2, 25-3 control the selectors 23-1, 23-2, 23-3, respectively, and switch from the working transmission line 10 to the backup transmission line 12. This recovers from the failure.

Alternatively, it can be easily realized by providing only one control circuit and controlling the switching of signals of all wavelengths.

Further, in the embodiment, a mode in which the protection operation is independently executed for each wavelength (a mode in which only the wavelength in which a failure is detected is switched from the active mode to the standby mode) and a mode in which the protection operation is collectively performed for all wavelengths (single wavelength It is also possible to operate a wavelength division multiplexing network by providing two modes (switching all wavelengths from active to standby even when a failure is detected) and setting from the outside to select one of the two modes. It is easily possible. For example, when the 1R repeater is used, the protection operation is performed collectively for all wavelengths, and when the 1R repeater is not used, the protection operation is independently performed for each wavelength.

If the total number of wavelengths in the transmission path is not required, the transmitting node inserts a specific pattern into an unused signal, and the receiving node detects the specific pattern, so that the signal is not used. It is possible to easily realize an operation mode in which the signal is recognized and the signal is discarded.

Next, a second embodiment of the present invention will be described. The second embodiment of the present invention relates to a wavelength division multiplexing 1: N protection system.

FIG. 8 shows a network configuration which is a target of this embodiment. In the wavelength division multiplexing transmission line shown in FIG.
Signals are transmitted by the wavelength multiplexing method using three wavelengths of 2 and λ3. Further, between the node 1-1 and the node 1-2,
The 1R repeaters 37-0 to 37-N and 38-0 to 38-N are connected. There are N active transmission lines for each direction, and the N active transmission lines share one backup transmission line 10-0 and 11-0.

Node 1 used in such a network
The configurations of -1 and 1-2 are shown in FIG. Node 1-1,
1-2 are transmission processing units 5-1 to 5-3 and a reception processing unit 6
-1 to 6-3, and control circuits 25-1 to 25-3 for making a decision to move the signal on the working transmission path to the backup transmission path according to the information from each monitoring circuit in the reception processing section, and the optical output of each transmission processing section Wavelength multiplexer 32-0 that wavelength-multiplexes (wavelengths λ1 to λ3)
~ 32-N, wavelength-multiplexed input optical signal (wavelength λ1
.About..lamda.3) are separated in wavelength units.
It consists of 3-N. The control circuits 25-1 to 25-3 are connected by a bus 17. Control circuits 25-1, 25
2, 25-3 are transmission processing units 5-1 and 5-2, respectively.
Control 5-3. Further, the control circuits 25-1, 25-
2, 25-3 are reception processing units 6-1, 6-2,
6-3 is controlled.

FIG. 10 shows the configuration of the transmission processing section 5-1.
The transmission processing unit 5-1 includes E / O converters 30-1-0 to 30-1-N (wavelength λ that converts an input electric signal into an optical signal).
1), control signal insertion circuit 34-1, input highway 40
-1-1 to 40-1-N is output Highway 41-1-0
41-1-N, the space switch 35-1-1 is connected to one of them. The transmission processing units 5-2 and 5-3 also have the same configuration as the transmission processing unit 5-1, but the wavelengths assigned to the respective transmission optical signals are different. Transmission processing unit 5-
2 is assigned the wavelength λ2, and the transmission processing unit 5-3 is assigned the wavelength λ3.

Next, FIG. 11 shows the configuration of the reception processing unit 6-1. The reception processing unit 6-1 includes O / E converters 31-1-0 to 31-1-N (wavelength λ that converts an input optical signal into an electric signal).
1), a monitoring circuit 21-0 to 21-N which detects a fault condition of a received signal and detects a control signal from within the received signal,
Input highway 43-1− according to the instruction of the control circuit
0-43-1-N is output Highway 44-1-1 to 44-44
It consists of a space switch 36-1-2 connected to -1-N. The reception processing units 6-2 and 6-3 have the same configuration as the reception processing unit 6-1, but the wavelengths assigned to the respective reception optical signals are different. The wavelength λ2 is assigned to the reception processing unit 6-2, and the wavelength λ3 is assigned to the reception processing unit 6-3.

The following is a description of the processing when a failure occurs in the E / O converter 30-1-1 of the transmission processing section 5-1 of the node 1-1 with the above configuration.

First, in the initial state, all N active transmission lines are normal, and the space switches 35-1-1 and the reception processing units 6-1 to 6- of the respective transmission processing units 5-1 to 5-3. Three
It is assumed that the space switch 36-1-2 selects the working transmission path.

E / O of the transmission processing section 5-1 of the node 1-1
When a failure occurs in the converter 30-1-1, the monitoring circuit 22-1-1 of the reception processing unit 6-1 of the node 1-2 will eventually occur.
Detects the occurrence of a failure. The monitoring circuit 22-1-1 notifies the control circuit 25-1 of the occurrence of a failure. Control circuit 25-1
Recognizes that a failure has occurred in the signal of wavelength λ1 on the working transmission line 10-1. The control circuit 25-1 of the node 1-2 inserts the control signal of the transmission processing unit 5-1 in order to notify the opposite node 1-1 of the occurrence of a failure in the working transmission line 10-1 by the control signal. The circuit is instructed to 34-1 to generate a control signal that conveys the occurrence of a fault. For the control signal transmission, the overhead portion of the signal transmitted on the backup transmission lines 10-0 and 11-0 may be used. Further, the control circuit 25-1 is connected to the other control circuits 25-2 and 25-3 by the bus 1
The failure detection is notified through 7.

The monitoring circuit 22-1-0 of the reception processing section 6-1 of the node 1-1 receives the control signal and transfers it to the control circuit 25-1. The control circuit 25-1 controls the space switch 35-1-1 of the transmission processing unit 5-1 and the highway 4 that has been transmitting using the working transmission line 10-1 until now.
The signal 0-1-1 is switched to be transmitted using the backup transmission line 10-0. Next, the control circuit 25-1 commands the other control circuits 25-2 and 25-3 to execute the switching operation. Control circuits 25-2, 25- which have received this command
3 is similar to the above processing, the transmission processing units 5-2, 5-3.
The space switch 35-1-1 is controlled.
By this processing, all the signals transmitted using the working transmission line 10-1 are moved to the backup transmission line 10-0.

Next, the control circuit 25-1 includes the transmission processing unit 5
-1 control signal insertion circuit 34-1 to instruct the active transmission line 1
A control signal for notifying the node 1-2 that 0-1 has been switched to the backup transmission line 10-0 is output.

The monitoring circuit 22-1-0 of the reception processing section 6-1 of the node 1-2 receives the control signal and transfers it to the control circuit 25-1. Control circuit 25-1 for node 1-2
Controls the spatial switch 36-1-2 of the reception processing unit 6-1 to switch so that the signal which has been received from the working transmission path 10-1 until now is received from the protection transmission path 10-0.
Further, the control circuit 1-2 of the node 1-2 has the transmission processing unit 5
The highway 40 which controls the space switch 35-1-1 of -1 and has transmitted using the working transmission path 11-1 until now.
The 1-1 signal is switched to be transmitted using the backup transmission line 11-0.

Next, the control circuit 25-1 of the node 1-2
The other control circuits 25-2 and 25-3 are also instructed to execute the switching operation. Control circuit 25-which received this command
2, 25-3 are similar to the above-mentioned processing, and the reception processing unit 6-
The control of the space switches 36-1-2 of 2 and 6-3 is executed. By this processing, all the signals received from the working transmission line 10-1 are switched to be received from the protection transmission line 10-0. Further, it controls the space switch 35-1-1 of the transmission processing units 5-2 and 5-3. By this processing, all the signals transmitted to the working transmission line 11-1 are moved to the backup transmission line 11-0.

Next, the control circuit 25-1 of the node 1-2
The control signal insertion circuit 34-1 of the transmission processing unit 5-1 is instructed,
A control signal for notifying the opposite node 1-1 that the working transmission path 11-1 has been switched to the protection transmission path 11-0 is output.

The monitoring circuit 22-1-0 of the reception processing section 6-1 of the node 1-1 receives the control signal and transfers it to the control circuit 25-1. Control circuit 25-1 of node 1-1
Controls the spatial switch 36-1-2 of the reception processing unit 6-1 to switch the signal previously received from the working transmission line 11-1 to the protection transmission line 11-0.

Next, the control circuit 25-1 of the node 1-1
The other control circuits 25-2 and 25-3 are also instructed to execute the switching operation. The control circuits 25-2 and 25-3 of the node 1-1 which received this command execute the control of the space switch 36-1-2 of the reception processing units 6-2 and 6-3 in the same manner as the above-mentioned processing. To do. By this process, all the signals received from the working transmission path 11-1 are switched to be received from the protection transmission path 11-0.

With the above, the switching process is completed. The sequence of the switching process is shown in FIG.

As a result of the operation, even if a fault is detected in the signal of a single wavelength in the current wavelength multiplexing transmission line, the signals of all wavelengths are moved to the backup transmission line. Further, even if a failure is detected in the signals of some wavelengths in the current wavelength multiplexing transmission line, it is possible to easily transfer the signals of all wavelengths to the backup transmission line.

In the embodiment, of the plurality of control circuits provided for each wavelength, one control circuit commands another control circuit to transmit a signal of a plurality of wavelengths wavelength-multiplexed on the working transmission line. Moved all together to the backup transmission line. In the protection operation, the control circuit that receives the failure detection from one monitoring circuit transmits the occurrence of the failure to the other control circuits, so that all the control circuits operate independently and the control circuit and the control circuit of the opposite node are controlled. It can also be easily realized by exchanging signals. Further, by notifying all the control circuits of the monitoring result of each monitoring circuit, all the control circuits operate independently, and it can be easily realized by exchanging the control signal with the control circuit of the opposite node. . Alternatively,
It can be easily realized by providing only one control circuit and controlling the signals of all wavelengths by the control circuit.

Further, in the embodiment, a mode in which the protection operation is independently performed for each wavelength (a mode in which only the wavelength in which a failure is detected is switched from the active mode to the standby mode) and a mode in which the protection operation is collectively performed for all wavelengths (single wavelength It is also easy to operate a wavelength division multiplexing network by providing two modes (switching all wavelengths from working to standby even when a failure is detected) and selecting one of the two modes by setting from the outside. Is possible. For example, when the 1R repeater is used, the protection operation is performed collectively for all wavelengths, and when the 1R repeater is not used, the protection operation is independently performed for each wavelength.

Next, a third embodiment of the present invention will be described. The third embodiment of the present invention relates to a wavelength division multiplexing 1: N protection system. FIG. 13 shows the network configuration that is the target of this embodiment.

In the wavelength division multiplexing transmission line shown in FIG. 13, λ1,
A signal is transmitted by a wavelength multiplexing method using three wavelengths of λ2 and λ3. However, only the transmission lines 10-1 and 11-1 have λ
Only two wavelengths of 1 and λ2 are used. Other working transmission lines 1
The number of wavelengths used in 0-2 to 10-N and 11-2 to 11-N is three. The number of wavelengths multiplexed on the backup transmission lines 10-0 and 11-0 is equal to the number of wavelengths of the transmission lines sharing the backup transmission lines 10-0 and 11-0 having the largest number of multiplexed wavelengths. (3 in the case of this example).

Between the node 1-1 and the node 1-2, 1
Connect the R repeater. There are N active transmission lines for each direction, and the N active transmission lines share one backup transmission line.
The node configuration is almost the same as in the second embodiment (FIG. 9).

In the network shown in FIG. 13, when a failure occurs in the working transmission line 10-0, the switching operation is executed by almost the same procedure as in the second embodiment. However, since the working transmission line 10-1 uses only two wavelengths of λ1 and λ2, one of the three wavelengths of the backup transmission lines 10-0 and 11-0 is used.
The wavelength (λ3 in this example) is unused. Therefore, the signal generation circuit 7 is connected to the transmission processing unit 5-3 for the wavelength λ3 of each node (FIG. 14). The output signal of the signal generation circuit 7 has a specific signal pattern indicating that the signal is unused. Based on this specific pattern, the receiving side recognizes that the signal transmitted at the wavelength of λ3 is unused and ignores it. The monitoring circuit is in charge of detecting the specific pattern. Switching can be performed by processing.

Alternatively, in the processing, the number of used wavelengths of the working transmission line and the protection transmission line is all set to be the same, and the working transmission line that does not require all the wavelengths (the working transmission lines 10-1 and 10-1 of the third embodiment).
Even in 1-1), by controlling the space switch of the transmission processing unit for unused wavelengths and connecting the signal generation circuit 7 to the O / E converter (a method similar to the method shown in FIG. 14), all wavelengths are changed. It can also be realized in a form in which it is used. In this case, the working transmission line that does not require all wavelengths (the working transmission line 10 of the third embodiment
When a failure occurs in -1, 11-1), switching is realized by moving signals of all wavelengths to the backup transmission line.

Even in this case, the output signal of the signal generating circuit 7 has a specific signal pattern indicating that the signal is unused. With this specific pattern, the receiving side recognizes that the signal transmitted at the wavelength of λ3 is unused and ignores it. Switching can be performed by processing.

[0079]

EFFECT OF THE INVENTION It is possible to provide a quick and reliable protection system for a wavelength division multiplexing transmission line.

[Brief description of drawings]

FIG. 1 is a block diagram of a node configuration according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional (1 + 1) protection system.

FIG. 3 is a block diagram of a 1: N protection method of a conventional example.

FIG. 4 is a block diagram of a conventional wavelength division multiplexing (1 + 1) protection system.

FIG. 5 is a block diagram of a conventional wavelength division multiplexing 1: N protection system.

FIG. 6 is a block diagram of a wavelength division multiplexing (1 + 1) protection network using a 1R repeater.

FIG. 7 is a block diagram of a system configuration when the outputs of a plurality of transmission devices are transmitted by wavelength division multiplexing.

FIG. 8 is a block diagram of a wavelength division multiplexing 1: N protection network according to a second embodiment.

FIG. 9 is a block diagram of a node configuration using the wavelength division multiplexing 1: N protection system according to the second embodiment.

FIG. 10 is a block diagram of a configuration of a transmission processing unit in the second embodiment.

FIG. 11 is a block diagram of a configuration of a reception processing unit in the second embodiment.

FIG. 12 is a switching control sequence diagram according to the second embodiment.

FIG. 13 is a block diagram of a wavelength division multiplexing 1: N protection network according to a third embodiment.

FIG. 14 is a block diagram of a transmission processing unit according to the third embodiment.

[Explanation of symbols]

10 ... Transmission path, 12 ... Transmission path, 17 ... Bus, 21-0
21-N ... Monitoring circuit, 22-0-22-N ... Monitoring circuit,
23-0 to 23-N ... selector, 25-1 to 25-3 ...
Control circuit, 31-1-0 to 31-1-N ... O / E converter (wavelength λ1), 31-2-0 to 31-2-N ... O / E converter (wavelength λ2), 31-3 -0 to 31-3-N ... O /
E converter (wavelength λ3).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H04B 10/08 H04J 1/16 H04B 9/00 K

Claims (23)

[Claims] 1. A transmission in which one or more working transmission lines and one or more protection transmission lines are duplexed, and a plurality of signals are multiplexed and transmitted on the working transmission line and the protection transmission line by a wavelength multiplexing method. In the system, when a failure is detected in one or more signals of the signals of the plurality of wavelengths that are wavelength-multiplexed and transmitted to the working transmission line, another wavelength that is wavelength-multiplexed and transmitted to the working transmission line. A method of wavelength multiplexing protection, characterized in that signals of all wavelengths including the above signal are transferred to the backup transmission line. 2. The same signal is transmitted to two different transmission lines,
In a transmission system in which a 1 + 1 protection method for selecting one side on the receiving side is used and a plurality of signals are multiplexed and transmitted on each transmission path by a wavelength division multiplexing method, the signals are wavelength-multiplexed and transmitted on the selected transmission path. If a failure is detected in one or more of the plurality of signals, the wavelength-multiplexed signal is transmitted to the non-selected side transmission line instead of all the signals that are wavelength-multiplexed and transmitted on the selected transmission line. A wavelength division multiplex protection method characterized in that all transmitted signals are selected. 3. A protection system in which the same signal is transmitted to N transmission lines and a signal arrived from one of the N transmission lines is selected on the receiving side by using a protection system, Is a transmission system in which a plurality of signals are multiplexed and transmitted by a wavelength multiplexing method, and when a failure is detected in one or more signals among the plurality of signals transmitted by wavelength multiplexing in the selected transmission path, Instead of all the signals that are wavelength-multiplexed and transmitted on the selected transmission path, the non-selected (N
-1) A wavelength multiplexing protection method characterized in that all signals that are wavelength-multiplexed and transmitted on one of the transmission lines are selected. 4. The wavelength multiplexing protection according to claim 2 or 3, wherein a specific pattern is inserted on the transmitting side for a signal not used for transmission of significant data among a plurality of signals wavelength-multiplexed on the transmission line. Method. 5. A 1: N protection system is used in which N working transmission lines share one protection transmission line, and a plurality of signals are multiplexed and transmitted by a wavelength multiplexing system on each working transmission line. In the transmission system, when a failure is detected in one or more signals among a plurality of signals wavelength-multiplexed and transmitted in one of the N working transmission lines,
A wavelength multiplexing protection method, characterized in that all signals wavelength-multiplexed and transmitted on the working transmission line are transferred to the backup transmission line. 6. A 1: N protection system is used in which N working transmission lines share one protection transmission line, and a plurality of signals are multiplexed by a wavelength multiplexing method on each of the working transmission lines and the protection transmission lines. In the transmission system in which the number of signals wavelength-multiplexed in each of the working transmission lines is not the same, the number of signals wavelength-multiplexed in the backup transmission line is wavelength-multiplexed in each of the N working transmission lines. When the number of signals to be wavelength-multiplexed on the working transmission line is equal to the largest number of signals and the signal of one working transmission line of the plurality of working transmission lines is transferred to the protection transmission line, If the number of signals wavelength-multiplexed on the transmission line is less than the number of signals wavelength-multiplexed on the backup transmission line, the dummy signal is subtracted from the number of signals wavelength-multiplexed on the backup transmission line on the transmission side. Generate,
The wavelength multiplexing protection method, wherein the effective signal and the dummy signal are wavelength-multiplexed and transferred to the backup transmission line. 7. A transmission system using a 1: N protection system in which N working transmission lines share one protection transmission line, and a plurality of signals are multiplexed on the working transmission line by a wavelength multiplexing method. , The number of signals multiplexed on each of the working transmission lines and the number of signals wavelength-multiplexed on the protection transmission lines are the same (value k: k is a natural number), and the effective number to be used for each of the N working transmission lines When the number of signals is less than k, the transmitting side uses j pieces (j is a natural number:
In addition to j <k) effective signals, (k−j) signals (dummy signals) are generated, the effective signals and the dummy signals are wavelength-multiplexed and transmitted, and the effective signals among the N active transmission lines are generated. When the signal of the working transmission line whose number is less than k is transferred to the backup transmission line, the effective signal and the dummy signal are wavelength-multiplexed,
A wavelength division multiplex protection method, characterized in that it is transferred to the backup transmission line. 8. A transmission system using a 1: N protection system in which N working transmission lines share one protection transmission line, and a plurality of signals are multiplexed on the working transmission line by a wavelength multiplexing method. , The number of signals multiplexed in the working transmission line and the number of signals wavelength-multiplexed in the protection transmission line are the same (value k: k is a natural number), and an effective signal to be used in each of the N working transmission lines When the number of is less than k, the transmitting side uses j pieces (j is a natural number: j
In addition to the effective signal of <k), (k−j) dummy signals are generated, the effective signal and the dummy signal are wavelength-multiplexed and transmitted, and the signal transmitted to the working transmission line is spared. When transferring to the transmission line, the data is transmitted to the working transmission line j.
A method of wavelength multiplexing protection, wherein the number of effective signals and the number of newly generated (k−j) dummy signals are wavelength-multiplexed and transferred to the backup transmission line. 9. The WDM protection method according to claim 6, wherein the dummy signal has a specific pattern indicating that the dummy signal is not the valid signal. 10. A switching processing mode for collectively performing protection processing on signals wavelength-multiplexed on the transmission path in a wavelength-multiplexed transmission path for inter-station transmission, and a plurality of signals wavelength-multiplexed on the transmission path. A wavelength division multiplex protection method having a switching processing mode for performing individual protection processing, and selecting and operating one of the two types of modes. 11. A 1 + 1 protection system in which the same signal is transmitted to two different transmission lines and one is selected on the receiving side, and L (L is a natural number) optical signals are wavelength-multiplexed on each transmission line. A transmission device for use in a transmission system that is multiplexed and transmitted by a method, comprising: separating means for separating wavelength-multiplexed optical signals received from the two transmission paths into wavelength units; It has opto-electric conversion means for converting each of the optical signals into an electric signal, and monitoring means for monitoring whether or not each of the electric signals is normally received, and for outputting an abnormality detection signal when an abnormality is detected. , Of the 2L signals converted into the electrical signals,
Selection for selecting two signals that transmit the same content (a signal received from one of the two transmission paths and a signal received from the other transmission path) and selecting one of the two signals If there are L units, and one or more of the L selecting units detects a failure in the signal being selected by the output from the monitoring unit, the selection unit is currently selected. A transmission device comprising: control means for issuing an instruction to select a non-selected signal in place of a signal and for issuing an instruction to select a currently non-selected signal to other selection means. 12. A 1 + 1 protection system in which the same signal is transmitted to two different transmission lines and one is selected on the receiving side, and L (L is a natural number) optical signals are wavelength-multiplexed on each transmission line. A transmission device for use in a transmission system that is multiplexed and transmitted by a method, comprising: separating means for separating wavelength-multiplexed optical signals received from the two transmission paths into wavelength units; It has an opto-electric conversion means for converting each of the optical signals into an electric signal and a monitoring means for monitoring whether or not each of the electric signals is normally received and outputting an abnormality detection signal when an abnormality is detected. Then, from the 2L signals converted into the electric signals,
L select means for selecting two signals transmitting the same content and selecting one of the two signals,
When the selection means is controlled and one or more selection means of the L selection means detects a failure in the signal being selected by the output from the monitoring means, the selection means is currently selected. A transmission device having L control means for issuing a command for selecting a non-selected signal instead of a signal and for issuing a command for selecting a non-selected signal to other control means. . 13. A 1 + 1 protection system in which the same signal is transmitted to two different transmission lines and one of them is selected on the receiving side, and L optical signals are multiplexed on each transmission line by a wavelength multiplexing method. A transmission device used in a transmission system for transmitting, wherein each of the wavelength-multiplexed optical signal received from the two transmission lines is separated by wavelength unit, and each of the optical signals separated by wavelength unit is separated. Opto-electric conversion means for converting to an electric signal, and having a monitoring means for monitoring whether each of the electric signals are normally received, and outputs an abnormality detection signal when an abnormality is detected, the electric signal to From the converted 2L signals, two signals that transmit the same content are selected, and L selection means for selecting one of the two signals are provided, and the selection means is controlled. The monitoring means When one or more of the L selecting means detects a failure in the signal being selected by the output of the above, the L selecting means are not selected instead of the currently selected signal. A transmission device having L control means for issuing an instruction to select the signal of. 14. A 1 + 1 protection system is used in which the same signal is transmitted to two different transmission lines and one of them is selected on the receiving side, and L optical signals are multiplexed by a wavelength multiplexing system on each transmission line. A transmission device used in a transmission system for transmitting, wherein each of the wavelength-multiplexed optical signal received from the two transmission lines is separated by wavelength unit, and each of the optical signals separated by wavelength unit is separated. The photoelectric conversion means for converting into an electrical signal, and a monitoring means for monitoring whether each of the electrical signals are normally received, and outputs an abnormality detection signal when an abnormality is detected, the electrical signal From the 2L number of signals converted to, two signals that transmit the same content are selected, and there are L selection means for selecting one of the two signals and controlling the selection means. , The monitoring hand When one or more of the L selecting means detects a failure in the signal being selected by the output from the above, the L selecting means are not selected instead of the currently selected signal. 2. A transmission device comprising a control means for issuing a command to select the signal. 15. A (1 + 1) protection system in which the same signal is transmitted to two different transmission lines and one of them is selected on the receiving side, and a plurality of optical signals are multiplexed on each transmission line by a wavelength multiplexing method. A transmission device for use in a transmission system for transmitting by means of separating means for separating wavelength-multiplexed optical signals received from the two transmission lines into wavelength units, and each of the optical signals separated into wavelength units. Is converted into an electric signal, a monitoring means for monitoring whether or not each of the electric signals is normally received, and an abnormality detection signal is output when an abnormality is detected, and a conversion means for converting the electric signal From the signal group received from one of the two transmission paths of the plurality of signals and the signal group received from the other transmission path, a selection means for selecting one by a command from the control means, and the monitoring means. When the selecting means detects a failure in one or more signals of the selected signal group by the output, the selecting means is instructed to select the non-selected signal group in place of the currently selected signal group. A transmission device comprising a control means for outputting. 16. A (1 + 1) protection system in which the same signal is transmitted to two different transmission lines and one of them is selected on the receiving side, and a plurality of signals are multiplexed on each transmission line by a wavelength multiplexing method. A transmission device used in a transmission system for transmitting, of a plurality of signals wavelength-multiplexed on the transmission path, for a signal not used for transmission of significant data, a specific pattern should be inserted on the transmission side. A characteristic wavelength multiplexing protection method. 17. A 1: N protection system in which N (N is a natural number) working transmission lines share one backup transmission line is used, and a plurality of signals are multiplexed on the transmission line by a wavelength multiplexing method. A transmission device used in a transmission system by bidirectional full-duplex communication, having a scale of at least N inputs (N + 1) outputs, where the 1st to Nth outputs are N of the 2N working transmission lines. Connected to the current transmission line of
The (N + 1) th output is a first one connected to one of the two backup transmission paths (the backup backup transmission path).
Control signal having switching control information for the output connected to the transmission side backup transmission line among the outputs of the k number of the first space switching means. And the i-th (i is a natural number: 1 ≦ i ≦ of the k first space switching means.
(N + 1) output is an optical signal of different wavelength (wavelength λ
1 to λk) having (N + 1) electro-optical converting means for wavelength-multiplexing the k optical signals of different wavelengths and outputting the wavelength-multiplexed optical signals to the transmission-side working transmission line and the transmission-side standby transmission line. And (N + 1) means for wavelength-multiplexed signals to be received from N working transmission lines (reception side working transmission lines) other than the transmission side working transmission line among the 2N working transmission lines, It has (N + 1) wavelength demultiplexing means for demultiplexing the wavelength-multiplexed signal received from a standby transmission line (reception side standby transmission line) other than the transmission side standby transmission line among the two backup transmission lines into wavelength units. , (N + 1) photoelectric conversion means for converting output optical signals (wavelengths λ1 to λk) of different wavelengths of the wavelength separation means into electric signals, and normality for each output electric signal of the photoelectric conversion Monitor and detect any abnormalities It has a monitoring means for outputting a signal and a control signal extracting means for extracting the control signal from the signal received from the reception side auxiliary transmission line, and selectively controls the output of the photoelectric conversion means, and at least (N + 1) inputs. It is a scale of N outputs, and the first to Nth inputs are connected to the receiving side working transmission line, and the (N + 1) th input has a second space switch means connected to the receiving side standby transmission line. However, when a failure is detected in any of the signals passing through the 2N working transmission lines, judging from the output of the monitoring result of the monitoring control means and the output of the control signal extracting means, the k first Space switch means, or the k second
By controlling the space switch means, all the signals passing through the working transmission line through which the signal in which the fault is detected pass are moved to the backup transmission line in the same direction as the working transmission line, or the fault is detected. All the signals passing through the working transmission line forming a two-way full-duplex communication path in combination with the working transmission line through which the transmitted signal is transferred to the backup transmission line in the same direction as the working transmission line, or A transmission device comprising: control means for issuing a command to the control signal insertion means to output the control signal. 18. A signal according to claim 17, wherein only j (j is a natural number: j <k) wavelength signals are used among k (k is a natural number) wavelength signals to be wavelength-multiplexed on each of the working transmission lines. Otherwise, one or more signal generating means are connected to the input of the first space switching means, and the control means uses the signal generating means and the k first space switching means,
When the signal generating means is connected to the electro-optical converting means for the (k−j) unused wavelength signals and the signal on the working transmission path is transferred to the backup transmission path, the output of the signal generating means is simultaneously output. A transmission device characterized by being transferred to a backup transmission line. 19. A 1: N protection system in which N (N is a natural number) working transmission lines share one protection transmission line, and a plurality of signals are multiplexed on the transmission line by a wavelength multiplexing method. A transmission device used in a transmission system by bidirectional full-duplex communication, wherein a plurality of input signals are input to the (2N +
2) Third spatial switch means for allocating to any one of (N + 1) transmission paths among the two transmission paths, and preliminary transmission of the transmission side transmission path out of the output of the third spatial switch means. A control signal inserting means for inserting a control signal into an output connected to the path, and transmitting one of the (N + 1) transmitting side transmission paths among the outputs of the third space switching means. (N + 1) electro-optical conversion means for converting a plurality of signals connected to the side transmission line into optical signals of different wavelengths (maximum k: wavelengths λ1 to λk), and the k optical signals of different wavelengths. (N + 1) wavelength multiplexing means for wavelength-multiplexing and outputting the wavelengths to the transmission line, and wavelengths received from (N + 1) transmission lines other than the transmission side transmission line among the (2N + 2) transmission lines Multiplexed optical signal (N + 1)
Opto-electric conversion means for converting (N + 1) number of wavelength separation means for separating the individual pieces into wavelength units and converting output optical signals (maximum k pieces: wavelengths λ1 to λk) of different wavelengths of the wavelength separation means into electric signals. (N + 1) are provided, the normality of each of the output electrical signals of the photoelectric conversion is monitored, and when an abnormality is detected, a monitoring unit that outputs an abnormality detection signal, and a signal received from the backup transmission line Control signal extraction means for extracting the control signal, and fourth spatial switch means for selectively controlling the output of the photoelectric conversion means are provided. From the monitoring result output of the monitoring control means and the output of the control signal extraction means. If a failure is detected in any of the signals passing through the 2N working transmission lines by judging, by controlling the third space switching means and the fourth space switching means,
Move all the signals passing through the working transmission line through which the fault is detected to the backup transmission line in the same direction as the working transmission line, or combine with the working transmission line through which the fault is detected. Move all signals passing through the working transmission line forming a bidirectional full-duplex communication path to the backup transmission line in the same direction as the working transmission line, or output a control signal to the control signal inserting means. A transmission device comprising control means for issuing a command to cause a transmission. 20. The number of signals wavelength-multiplexed on the backup transmission line is k (k is a natural number), and the number of signals wavelength-multiplexed on each of the working transmission lines is j. (J
Is a natural number: j <k) When transferring the signal of the working transmission line to the backup transmission line, one or more signal generating means are provided,
The signal generating means is connected to the input of the third space switching means, and the control means is wavelength-multiplexed to the working transmission line by the signal generating means and the third space switching means. A transmission device, wherein a signal and an output signal of the signal generating means are connected to the electro-optical converting means, wavelength-multiplexed, and transferred to a backup transmission line. 21. In claim 19, the numbers of signals wavelength-multiplexed on the working transmission line and the protection transmission line are all the same (value k:
k is a natural number), and if only j (j is a natural number: j <k) wavelength signals are used among the k (k is a natural number) wavelength-multiplexed wavelength signals in each working transmission line, One or a plurality of signal generating means is connected to an input of the third space switch means, and the control means uses the signal generating means and the third space switch means, and (kj)
When the signal generating means is connected to the electro-optical converting means for signals of unused wavelengths and the signal of the working transmission path is transferred to the backup transmission path, the output of the signal generating means is simultaneously transferred to the backup transmission path. apparatus. 22. The method according to claim 18, 20 or 21,
The signal generated by the signal generating means includes a specific pattern. 23. A transmission device used for a wavelength division multiplex transmission line for inter-station transmission, comprising a switching processing operation mode for collectively protecting signals wavelength-multiplexed on the transmission line, and a wavelength for the transmission line. A transmission apparatus having a switching processing operation mode for individually performing protection processing on a plurality of multiplexed signals, and operating by selecting one of the two types of modes.