JP2003046456A - Optical transmission network system and fault monitor method for the optical transmission network system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical multiplex transmission system that can monitor a transmission line fault at an optical level. SOLUTION: In the optical transmission network where a plurality of optical transmitters being optical ADM devices are interconnected by service use (active) and protection purpose (standby) optical transmission lines and data subjected to wavelength multiplexing of optical signals with particular wavelengths are transmitted among devices at ends contained in the optical transmitters, the optical transmitter is provided with an optical monitor channel optical signal generating means 27 that generates an optical signal with an optical monitor channel by an optical signal with a wavelength different from that of the optical signal used for wavelength multiplexing, a synthesis means 23 that adds an optical signal from the optical monitor channel optical signal generating means to the optical signal subjected to wavelength multiplex light and transmits the sum to the transmission line, an optical branching device 21 that extracts an optical signal with the optical monitor channel among the optical signals sent via the transmission line, and a monitor means 22 that monitors a fault in the transmission line from the optical signal of the optical monitor channel branched by the optical branching device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of optical ADM devices, which are connected by service (current) and protection (spare) optical transmission lines to connect terminal devices accommodated in the optical ADM device. The present invention relates to an optical transmission network system for transmitting an optical signal having a unique wavelength, and more particularly to an optical transmission network system capable of monitoring a transmission line fault at an optical signal level and a fault monitoring method for the optical transmission network system.

[0002]

2. Description of the Related Art With the widespread use of high-speed Internet and broadband multimedia services, there is an urgent need to increase the capacity of transmission lines of information and communication networks and improve their economic efficiency. Among them, optical fiber communication technology is one of the important network construction technologies.

In an optical fiber transmission system, Time Division Multiplexing (TDM: Time Division Multiplexing) has been used so far to increase the speed of a signal transmitted in one optical fiber on a time axis.
ltiplexing) method to increase capacity.

However, due to the explosive increase in traffic in recent years, there is an urgent need to further increase the transmission capacity.

On the other hand, an optical fiber amplifier which was put into practical use in the 1990s enabled amplification without converting an optical signal transmitted through the optical fiber into an electric signal.
In the optical fiber amplifier, since it is possible to multiplex optical signals of different wavelengths in one optical fiber and to amplify and relay the optical signals collectively in multiple wavelengths, the wavelength multiplexing (WD
M: Wavelength Division Multiplexing (M) method is being studied, and the dramatic increase in transmission capacity and long-distance transmission have become a reality.

In addition, in a transmission system using such a WDM system, in order to avoid an increase in scale proportional to the number of wavelengths to be multiplexed in this way, Add / Drop is performed in wavelength units for wavelength-multiplexed transmission. Optical ADM (Optic based on
Application of al Add / Drop Multiplexer (OADM) technology is being studied.

The optical ADM processes only the wavelength to be accessed among a plurality of wavelength-multiplexed wavelengths as an Add / Drop channel, and ultimately, an all optical network (All Optical Network) ) Can be said to be aimed at.

A conventional optical transmission device used in a wavelength multiplexing ring network using the optical ADM technology will be described. Here, a so-called F is used to form a ring network with a transmission line fiber for the active system and a transmission line fiber for the standby system.
Consider, for example, an optical transmission device having an FRN (Four Fiber Ring Network) configuration. The concept of this type of device is described in the following references, for example. Rainer Iraschko et.al “An Optical 4-Fiber bi-direc
The optical transmission equipment uses an optical signal that has been wavelength-multiplexed and transmitted through a transmission line fiber by an optical wavelength demultiplexing function unit (WDM-R) for each wavelength. , λn are once separated.
The separated optical signals of respective wavelengths λ1, λ2, ..., λn are input to an optical matrix functional unit such as an optical cross connect.

The optical matrix functional unit extracts optical signals of wavelengths λi, λj, and λk of preset specific channels to the low-order group side (Drop), and passes optical signals of other wavelengths (Through). Output to the adjacent station. In addition, the optical matrix function unit has the dropped wavelengths λi, λj, and λ.
The signal at the local station is added to the channel of k and output as an optical signal for transmission at the adjacent station. Then, this optical signal to be transmitted to the adjacent station is transmitted to the optical wavelength multiplexing function unit (WDM-
In T), the wavelengths are multiplexed and transmitted through the output side transmission line fiber.

[0010]

By the way, an optical AD which multiplexes a plurality of optical signals and performs Add / Drop for each wavelength.
Multiple M devices, service line (SRV (active line) transmission line) and protection line (PRT (standby line)
When a network connection is made using the transmission line (1), the network line connection is a ring connection, and a failure occurs in the service line between the optical ADM devices,
A so-called APS (Automatic Pr) that autonomously switches to a protection line to protect the line
In order to have an otection switching function, it is necessary for each optical ADM device to notify each other of the switching state.

However, since the optical ADM apparatus cannot recognize the information content of the optical signal, when the APS function is realized by the optical ADM apparatus, the above notification must rely on the electric signal.

Therefore, even though it is an optical network system, it is necessary to separately prepare a line for exchanging electric signals. The switching state notification signal is sent and received as an electric signal, and the control signal is also sent and received at the electric signal level.

Therefore, in spite of using the optical ADM apparatus which tries to do all at the optical signal level, the line for transmitting and receiving the electric signal is indispensable for controlling the line protection. Will end up.

By the way, in the fault monitoring at the electric signal level, generally, an AIS (Alarm Indication Signa) which is an alarm signal for notifying that the faulty section is in progress.
l) A signal and a signal called FERF (Far End Receive Failure) are used.

That is, when data is transmitted by electric signals via a network, for example, in a point-to-point system, when a failure occurs in a transmission line, the failure occurrence section is bypassed or disconnected. It is necessary to control the transmission line switching of the above so that the failure can be minimized. Therefore, these AIS signal and FERF signal are used as a mechanism for notifying the upstream node and the downstream node of the failure from the detected node.

A brief explanation of this mechanism is as follows:
In a ring network system that performs digital signal processing such as SDH and a system that performs network protection, an AIS signal is used for a downstream node and a FERF signal is used for an upstream side.

That is, by transmitting an AIS signal, which is a signal of a certain pattern, to the downstream node,
By receiving this signal, the node on the downstream side recognizes that a failure has occurred on the upstream side. This is AI
This is a mechanism for informing downstream using S.

The other is a mechanism for notifying the upstream side, and returns a FERF signal to the upstream side in order to notify the node on the upstream side adjacent to itself that the transmission from the upstream side has a failure. To do so. This FERF uses a sync signal for frame synchronization, which is added to a part of this overhead and is sent, although other information is sent by adding overhead to the original data signal to be sent, and this cannot be detected. Detect anomalies from symptoms.

In this way, by notifying the adjacent node of the occurrence of the failure by the signal of AIS or FERF from the node which has detected the failure, each node knows the occurrence of the failure,
By specifying the faulty section and then controlling the circuit switching such as bypassing the faulty section or looping back before the faulty section, the influence of the faulty section is minimized and data transmission is continued. I am able to

On the other hand, in recent years, in order to further increase the transmission capacity and increase the transmission speed, attention has been paid to a system in which an optical signal is transmitted on an optical network. However, even if optical transmission is carried out, the merit is halved in a system configuration that needs to be converted into an electric signal for fault monitoring.

That is, in order to realize the network protection system by the optical ADM, in the case of the conventional technique, the line failure cannot be detected at the optical level. Therefore, the optical signal is once converted into the electric signal, and this electric signal is converted. By monitoring, the occurrence of a line failure is inevitably monitored, and control signals must be exchanged at the electrical signal level.

For that purpose, photoelectric conversion at each interface in each optical ADM apparatus is required, which leads to a significant increase in signal processing time and circuit scale, which is the greatest merit of transmission by an optical signal. It is a hindrance to a certain increase in transmission capacity and increase in transmission speed. Therefore, there is an urgent need to quickly establish a technique for monitoring an optical signal as it is.

Therefore, the object of the present invention is to
An optical multiplex transmission system capable of monitoring a transmission line fault at an optical level in an optical multiplex transmission system in which an optical signal of a specific wavelength is used for each destination and an optical signal of each wavelength is multiplexed and transmitted. An object of the present invention is to provide a fault monitoring method for an optical multiplex transmission system.

[0024]

In order to achieve the above object, the present invention is configured as follows. That is, optical ADM
A plurality of optical transmission devices are connected by a service (current) and protection (spare) optical transmission line, and the end devices accommodated in the optical transmission device have wavelengths with optical signals of unique wavelengths. In an optical transmission network that multiplexes and transmits data, [1] Firstly, in the optical transmission device, an optical signal of an optical supervisory channel is generated by an optical signal of a wavelength different from an optical signal used for wavelength multiplexing. The optical supervisory channel optical signal generating means, the multiplexing means for adding the optical signal from the optical supervisory channel optical signal generating means to the wavelength-multiplexed optical signal and sending the optical signal to the transmission line, and the optical signal are transmitted through the transmission line. An optical branching device for extracting the optical signal of the optical monitoring channel from the optical signals, and a monitoring means for monitoring the transmission line fault from the optical signal of the optical monitoring channel branched by the optical branching device. To Characterize.

[2] Secondly, in the optical transmission device, an optical signal of an optical supervisory channel is generated by an optical signal of a wavelength different from the optical signal used for wavelength division multiplexing, and at the time of line failure, AIS Optical supervisory channel optical signal generating means for generating an optical signal of the optical supervisory channel to which a signal is added, and an optical signal from the optical supervisory channel optical signal generating means is added to the wavelength-multiplexed optical signal to a transmission line. A multiplexing means for sending out, an optical branching device for extracting the optical signal of the optical monitoring channel from the optical signals transmitted through the transmission path, and an optical signal of the optical monitoring channel branched by the optical branching device. And a monitoring means for detecting a transmission line fault.

[3] Thirdly, in the optical transmission device, an optical signal of an optical supervisory channel is generated by an optical signal of a wavelength different from the optical signal used for wavelength division multiplexing, and when the line fails, the AIS is used. Optical supervisory channel optical signal generating means for generating an optical signal of the optical supervisory channel to which a signal is added, and an optical signal from the optical supervisory channel optical signal generating means is added to the wavelength-multiplexed optical signal to a transmission line. A multiplexing means for sending out, an optical branching device for extracting the optical signal of the optical monitoring channel from the optical signals transmitted through the transmission path, and an optical signal of the optical monitoring channel branched by the optical branching device. And a means for transmitting an AIS signal in place of data to the terminal side which the self accommodates when the monitoring means detects a transmission path failure. .

In the above configuration [1], from the optical transmission apparatus on the upstream side of the optical transmission apparatus, the optical signal of the optical supervisory channel by the optical signal of the wavelength different from the optical signal used for wavelength multiplexing is transmitted. A signal is generated and transmitted to the transmission line, and at the downstream side, the transmitted optical signal of the optical monitoring channel is extracted and the transmission line fault is monitored from the state of the extracted optical signal.

As described above, according to the invention [1],
If a failure occurs in the transmission line, the optical signal of the optical monitoring channel will be cut off.Therefore, if the optical signal state of the optical monitoring channel is monitored, the optical path of the optical signal will not be converted into an electrical signal and the transmission line failure will remain. Will be able to monitor.

Further, in the above configuration [2], the optical transmission device on the upstream side of the optical transmission devices transmits the light of the optical supervisory channel by the optical signal of the wavelength different from the optical signal used for wavelength multiplexing. A signal is generated, and at the time of a line failure, an optical signal of an optical monitoring channel to which an AIS signal is added is generated and transmitted to the transmission path, and on the downstream side, the optical signal of the transmitted optical monitoring channel is extracted, The transmission line fault is monitored from the state of the extracted optical signal.

As described above, according to the invention [2],
When a failure occurs in the transmission line, the optical signal of the optical supervisory channel is cut off, and line failure (transmission path failure) occurs on the upstream side.
In the case of detecting, the AIS signal is added to the optical signal of the optical supervisory channel from the upstream side, so that it becomes possible to know the occurrence of the failure. Therefore, if the state of the optical signal of the optical monitoring channel is monitored, it becomes possible to monitor the transmission line failure without changing the state of the optical signal without converting it into an electric signal.

Further, in the above-mentioned constitution [3], from the optical transmission apparatus on the upstream side of the optical transmission apparatus, the optical signal of the optical supervisory channel by the optical signal of the wavelength different from the optical signal used for wavelength multiplexing is transmitted. A signal is generated, and at the time of a line failure, an optical signal of the optical monitoring channel to which an AIS signal is added is generated and transmitted to the transmission line, and on the downstream side, the optical signal of the transmitted optical monitoring channel is extracted. The transmission line fault is monitored from the state of the extracted optical signal. Then, when a transmission line failure is detected,
An AIS signal is sent instead of data.

As described above, according to the invention [3],
When a failure occurs in the transmission line, the optical signal of the optical supervisory channel is cut off, and line failure (transmission path failure) occurs on the upstream side.
In the case of detecting, the AIS signal is added to the optical signal of the optical supervisory channel from the upstream side, so that it becomes possible to know the occurrence of the failure. Therefore, if the state of the optical signal of the optical monitoring channel is monitored, it becomes possible to monitor the transmission line failure without changing the state of the optical signal without converting it into an electric signal. When a transmission line failure is detected, the AIS signal is sent to the terminal side that it is accommodating instead of the data, so that the transmission line failure remains as an optical signal without conversion to an electrical signal. I will be able to inform you.

[0033]

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

The present invention is a supervisory channel (OSC: Opti) using a specific wavelength different from the wavelength of the optical signal for data transmission.
cal supervisory channel) so that AIS can be added to the frame of this monitoring channel when a failure is detected, and the optical signal of this monitoring channel is multiplexed with the multiplexed optical signal for data transmission. Transmission, and the monitoring channels are separated and monitored on the downstream side of the transmission line so that the disconnection of the transmission line (path) can be detected at the optical level. When the transmission line disconnection is detected, the tributary side An optical signal having an AIS pattern is sent instead of the Drop-connected signal, and the AIS is inserted into the optical signal of the supervisory channel on the downstream side of the transmission line to be sent, so that line failures occur one after another on the downstream side of the transmission line. The technique will be described in detail below.

First, an optical ADM to which the technique of the present invention is applied
The network system will be described.

In the functional block diagram of this specification, for convenience of explanation, the left side of the optical transmission device is referred to as WEST and the right side thereof is referred to as EAST. Also, in the figure, the notation SRV means the active system (Service), and PRT is this SR.
It means a protection system for V.

<System Configuration> FIG. 1 is a diagram showing an example of an optical ADM network to which the present invention is applied. This optical ADM network is composed of a plurality of nodes (optical transmission devices) 1 to 4 using optical ADM devices, a fiber pair (optical fiber pair) as a working transmission line, and a fiber pair as a standby transmission line. In addition, an optical fiber transmission line for connecting the nodes 1 to 4 in a ring shape by using the fiber pair of the working system and the protection system is provided.

Although the figure shows a case where two bidirectional pairs are connected by a total of four optical fibers, the present invention is limited in its application to a transmission system by a network in which nodes are connected by four fibers. However, it is also applicable to a system connected by two fibers or a system connected by four or more fibers.

Further, FIG. 1 shows a ring network in which nodes are connected in a ring shape.
It is not necessarily limited to the ring form, for example,
It is also applicable to a linear system in which some of the nodes in FIG. 1 are not connected. Further, the present invention also includes in its application range a WDM (Wavelength Division Multiplexing) transmission system that multiplexes and transmits a plurality of optical signals of different wavelengths on one transmission line fiber.

Each of the nodes 1 to 4 using the optical ADM device is
All signals that are input to and output from each of these nodes, that is, optical signals on the optical fiber transmission line and tributary (Tributary)
ary) has a function of setting the connection relationship between signals according to the situation. Here, the tributary signal is a signal input to each node from outside the ring network,
It means the signal output from each node to the outside of the ring network, and the tributary signal input to a certain node is
It is finally output as a tributary signal output of another node via the ring network.

Further, in the figure, both Tributary 1 and Tributary 2 indicate the tributary side, and these tributary sides Tributary 1 and Tributary 2 both send out a signal input to the node from the outside of the network to the network, A device for outputting a tributary signal transmitted through a network from a node to the outside of the network, and a device for adding / dropping an optical signal and transmitting / receiving the signal.

In the figure, the tributary signal is shown to be input and output for each of the two channels at each node.
In the present invention, the number of tributary signal channels input to and output from each node is not limited to two.

Hereinafter, for convenience, in the text, one of the transmission lines connected to the node is WEST and the other is EAS.
Notated as T (east). In addition, the West side active transmission line is set to West Service (West Service; West
SRV), the protection transmission line is West Protection (West Protection; West PRT), and the active transmission line on the EAST side is East Service (East service; E).
ast SRV), the protection transmission line East Protection
(East protection; East PRT). Also, in the network as shown in FIG. 1, an information transmission path between a tributary of a node and a tributary of another node is described as a path, and information transmitted via the path is described as traffic.

Next, the optical signal which is mounted on each of the nodes 1 to 4 is added / dropped or added.
/ T which connects to the transmission line without dropping / dropping
The optical switch device (hereinafter referred to as a line switch unit) that optically realizes the function of switching and setting the connection relationship between signals such as a “through” connection, and the configuration of each node 1 to 4 will be described in detail. Explained.

<Node Configuration to which the Present Invention is Applied> The nodes (optical transmission devices) 1 to 4 on which the line switch section according to the present invention is mounted are configured, for example, as shown in FIG.

Here, the character SRV is used for the active system, that is, the service system, and P for the standby system, that is, the protection system.
Displayed with the letters RT.

The node of FIG. 2 is composed of an optical transmission device 100 composed of an optical ADM device having a line switch device. The optical transmission device 100 includes wavelength demultiplexing units 1-1 to 1-4 for performing a plurality of wavelength demultiplexing processes and line interface units 2-1-1 to 2-1 for interfacing with lines in both directions for each wavelength. -4 and the line switch section SRV system 3-1 that has a function to add / drop / through connect signals of each wavelength and bridge the signals.
-1 to 3-1-2 and the tributary interface section 6-1 for interfacing with the tributary side
1-6-1-3, optical cross-connect units 4-1 and 4-2 for arbitrarily setting connection between the tributary interface channel and wavelength channel, and tributary interface units 6-1-1-6 -1-3 Tributary switch section SRV system for performing redundant switching of signals accommodated 5-
1-1 to 5-1-2.

The above line interface section 2-1-1
To 2-1-4 and the line switch units 3-1-1 to 3-1
-2 constitutes the optical ADM unit 20.

In FIG. 2, the line interface unit 2
-1-1 to 2-1-4 and line switch SRV system 3-
The functional blocks including 1-1 to 1-3-2 and the control unit 50 are provided for each optical signal of each wavelength, and therefore the number thereof increases as the wavelength multiplicity increases. In the figure, in order to distinguish individual wavelengths, an index of 1 to s is given, and the functional blocks are given symbols of # 1 to #s.

In FIG. 2, the functional block provided with the tributary switch section SRV systems 5-1-1 to 5-1-2 and the tributary interface sections 6-1-1 to 6-1-3 are as follows. It is provided for each channel on the tributary side (low speed side), and therefore the number changes according to the increase or decrease in the number (t) of low speed side channels. Below,
The low speed side channels are distinguished by adding the symbols ch 1 to ch t.

In particular, the tributary interface section 6-
Some of the traffic related to 1-3 is called part-time traffic. Here, part-time traffic uses a tributary line part-time system that is different from the tributary line service system and tributary line protection system when the node protection system functional block is not used to transmit service traffic. Traffic that has been transmitted in the order of priority and has lower priority than the service traffic.

Further, in the present invention, in order to be able to detect all the line faults in the optical transmission line at the optical level, an optical supervisory channel (OSC: Optical Sup) using a dedicated wavelength is used.
ervisory Channel) is prepared, and the optical signal of the optical supervisory channel is multiplexed with the optical signal of the data to be optically multiplexed and transmitted. Therefore, the optical transmission device 100
Is equipped with an optical monitoring channel light source 27 which is a light source therefor.

The optical supervisory channel light source 27 is different from the wavelengths λ0 to λn for signal transmission of each channel to be transmitted, and the wavelength range is λos which is separated to such an extent that it can be easily separated.
c is a light source that generates light of a specific wavelength component, has a predetermined frame structure, and is an optical signal generation source that can send an AIS flag for each wavelength λ0 to λn for signal transmission of each channel. There is. The optical monitoring channel light source 27 is W
It is possible to output as separate optical supervisory channel optical signals for the EST side and the EAST side.
The T-side optical supervisory channel optical signal is provided to the WEST-side wavelength demultiplexing unit, and the EAST-side optical supervisory channel optical signal is provided to the EAST-side wavelength demultiplexing unit. is there.

As is well known, the AIS is an alarm signal for notifying that a faulty section exists when a fault occurs on the transmission path.

As the AIS flag added to the optical supervisory channel optical signal, for example, "0" is used when normal and "1" is used when abnormal, and the wavelength λosc having a predetermined transmission frame is used.
In this format, the AIS flag is inserted in the optical signal. A predetermined transmission frame including this AIS flag is set to W
The control for generating an optical signal for each of the EST side and the EAST side is performed by the monitoring control unit 30 provided in the optical transmission device 100.

The monitoring control unit 30 receives an alarm from the OSC monitoring unit 22 via the tributary interface units 6-1-1 to 6-1-3 when a transmission failure is detected, or
When the AIS signal from the tributary side when a transmission failure is detected or when the error detection signal from the tributary side is received, the optical monitoring channel optical signal λosc in which the AIS flag “1” at the time of abnormality is inserted in the transmission frame Is generated by the optical supervisory channel light source 27, the optical supervisory channel optical signal λosc in which the AIS flag “0” in the normal state is inserted in the transmission frame is used in other cases.
Is generated, the optical monitoring channel light source 27 is controlled.

Further, the optical transmission device 100 transmits the wavelengths λ0 to λn for signal transmission of each channel, and branches the light having a specific wavelength component λosc,
Optical supervisory channel light source 2 for optical signals transmitted after being multiplexed
7, an optical multiplexer 23 for multiplexing an optical signal λosc from the optical signal λosc, and an optical signal λosc for the optical supervisory channel branched by the optical splitter 21.
And an OSC monitoring unit 22 for generating an alarm signal for switching the optical switch when the optical signal is interrupted, and the tributary interface units 6-1-1 to 6-1.
-3, an optical switch 25 for path switching by an alarm signal from the OSC monitoring unit 22, and an AIS
AIS pattern optical signal source 2 for generating a pattern optical signal
6 is provided.

The optical switch 25 is provided in the tributary interface units 6-1-1 to 6-1-3,
Normally, the tributary switch unit 5 located on the upstream side 5-
Although the route is held so that the optical signals from 1-, 5-1-2 are sent to the tributary side through the tributary interface I / F, the route is switched by the alarm signal from the OSC monitoring unit 22. When performed, the switch switches the path to the AIS pattern optical signal source 26 side, and functions as a flow of the AIS pattern optical signal from the AIS pattern optical signal source 26 to the tributary side via the tributary interface.

Tributary interface section 6-1-1
In this way, normally, 6-1-3 function so as to flow the optical signal of each transmission channel from the upstream side to the tributary side, and the optical signal of each transmission channel is sent by the alarm signal from the OSC monitoring unit 22. Instead of the signal, the AIS pattern optical signal functions to flow to the tributary side, and the optical signal transmitted from the tributary side functions to flow to the upstream side.

As described above, in this embodiment,
Since a 4-fiber-optical ring system is assumed, the optical transmission device 100 has a service fiber pair that is a current optical transmission line and a protection fiber pair that is a standby optical transmission line. There is an input side and an output side. Therefore, of the service fiber pairs,
It is assumed that the clockwise fiber is 10-1, the counterclockwise fiber is 10-2, and the clockwise fiber is 10-3 and the counterclockwise fiber is 10-4 in the protection fiber pair. , Each has an input side and an output side. Therefore, in the optical transmission device 100, the optical branching device 21 is arranged in the front side of the wavelength demultiplexing unit located on the input side of each fiber, and the optical multiplexer is provided in the rear stage side of the wavelength demultiplexing unit located on the output side. The container 23 is provided.

Specifically, the WEST of the fiber 10-1
From the SRV side into the wavelength demultiplexing unit 1-1, along the transmission line from the EAST SRV side of the fiber 10-2 into the wavelength demultiplexing unit 1-3, and from the WEST PRT side of the fiber 10-4 to the wavelength. Demultiplexer 1-
2 on the way to the transmission line and fiber 10-3 EASTP
In the middle of the transmission line entering the wavelength demultiplexing unit 1-4 from the RT side,
An optical branching device 21 is provided for each of the wavelength division multiplexers 1-1.
From the fiber 10-1 to the WEST SRV side of the transmission path and from the wavelength demultiplexing unit 1-3 to the fiber 10-
2 in the transmission path entering the EASTSRV side, and from the wavelength demultiplexing unit 1-2 to the WEST P of the fiber 10-4.
An optical multiplexer 23 is arranged in the transmission path entering the RT side and in the transmission path entering the EAST PRT side of the fiber 10-3 from the wavelength demultiplexing unit 1-4.

Next, the operation of the present system having such a configuration will be described. First, the switching function of the optical transmission device configured as shown in FIG. 2 will be described. The optical transmission device according to the present embodiment has a switchable redundant system inside the device, an optical cross-connect unit that performs wavelength assignment between the line side and the tributary side, and is used in a four-fiber transmission system.

<Case where there is no fault on the network> The optical transmission device of FIG. 2 sends service traffic (traffic in the service system) to the Add / Drop direction in the WEST direction.
(The signal flow from the tributary side to the line side is "Ad
"D direction", the signal flow from the line side to the tributary side is referred to as "Drop direction"), and in a normal state where there is no fault on the network, "A"
In the “dd direction”, the service traffic accommodated in the SRV (service) tributary interface unit 6-1-1 is subjected to signal format conversion, signal monitoring, or termination processing as necessary, and then the SRV tributary interface. Switch unit 5-1-1 and tributary switch unit PRT
The output is branched to the system 5-1-2. In the tributary switch section 5-1-1, when the tributary interface side is normal, the tributary interface section 6-1-1.
Select the signal from the SRV optical cross-connect unit 4
Output to -1.

The optical cross-connect unit 4-1 connects the service traffic in the Add direction selected by the tributary switch unit 5-1-1 to the wavelength channel according to the connection setting, and the SRV line switch unit 3-1-1. Output to. The SRV system line switch unit 3-1-1 connects the Add direction service traffic from the optical cross connect unit 4-1 to the WEST service direction (WEST SRV) line interface unit 2-1-1 and outputs it.

In the West SRV system line interface unit 2-1-1, the line switch unit 3-1-1, the optical cross connect unit 4-1 and the tributary switch unit 5 are provided.
-1-1 If all are normal, line switch unit 3-1
-1 output, and PRT (protection) when a failure is detected in any of the above functional blocks
System line switch unit 3-1-2 is selected, line overhead signal insertion processing is performed as necessary, and WES
The signal is output to the T SRV wavelength division multiplexer 1-1.

WEST SRV wavelength division multiplexer 1-
In 1, the WEST SRV system line interface unit 2-1-1 is wavelength-multiplexed with the signals from the other wavelength line interface units in the WEST SRV system, and the WEST SRV system service line (transmission line;
Fiber).

The "Drop direction" is as follows. The wavelength-multiplexed line signal accommodated by the WEST SRV wavelength division multiplexer 1-1 is wavelength-demultiplexed and
EST SRV system line interface unit 2-1-1
Is output to. The line interface 2-1-1 performs termination processing of the line signal as necessary, and the SRV
The output is branched to the system line switch unit 3-1-1 and the PRT system line switch unit 3-1-2.

The line switch unit 3-1-1 selects the signal from the line interface unit 2-1-1 of the West SRV system when there is no fault on the network,
It is output to the SRV optical cross-connect unit 4-1 as Drop-direction service traffic.

In the optical cross connect section 4-1, the Drop direction service traffic from the line switch section 3-1-1 is connected to the tributary channel according to the connection setting, and the SRV system tributary switch section 5-1-1 is connected. Output to.

In the tributary switch section 5-1-1,
The Drop-direction service traffic from the optical cross-connect unit 4-1 is branched and output to the SRV system tributary interface unit 6-1-1 and the PRT system tributary interface unit 6-1-2.

In the SRV system tributary interface section 6-1-1, the SRV system line switch section 3-1 is provided.
1. If all of the SRV optical cross-connect unit 4-1 and the SRV tributary switch unit 5-1-1 are normal, the output from the tributary switch unit 5-1-1 is When a failure is detected in any of the functional blocks, the PRT tributary switch unit 5-1
-2 is selected, the tributary overhead signal is inserted as necessary, and the tributary signal is output.

Next, a case where a failure occurs on the network will be described. In this case, only the part where the flow of service traffic changes will be explained. Regarding “Add direction”,
In the SRV system line switch unit 3-1-1, the Add direction service traffic from the SRV system optical cross-connect unit 4-1 is added to the West SRV direction line interface unit 2-1-1 and the West PRT direction line interface unit. The output is branched to 2-1-2.

Line interface section WEST SRV
The operations of the system 2-1-1 and the wavelength demultiplexing unit WEST SRV system are the same as in the normal state.

Line interface part West PRT
In the system 2-1-2, the SRV system line switch unit 3-1
The output from -1 is selected, a line overhead signal is inserted if necessary, and output to the wavelength demultiplexing unit 1-1 of the WEST PRT system.

In the wavelength demultiplexing section 1-1, the WEST P
The signal from the RT system line interface unit 2-1-2 is wavelength-multiplexed with the signal from the other wavelength line interface unit of the WEST PRT system and is output to the WEST PRT system line (transmission line; fiber).

The SRV line switch section 3-1 is used.
-1 bridges the optical signal provided via the SRV optical cross-connect unit 4-1. The signal branching output (bridge) to this line allows the node facing on the WEST side to receive service traffic through the protection line (transmission line of the backup system), and before switching to the protection line. While confirming the normality of the reception line signal,
The interruption time at the time of switching can be minimized.

Regarding the "Drop direction", the flow of service traffic and the flow of service traffic are the same.

In this way, when an optical transmission line (path) constituting an optical ADM network has a fault, the optical transmission device (node) having the configuration of FIG. 2 detours the faulty optical transmission line. Therefore, it is possible to realize a configuration capable of continuing optical transmission.

The problem here is how to detect the occurrence of a failure in the optical transmission line, and how to know the location of the failure and bypass it. It is very difficult to detect the faulty bus as it is because the other party is an optical signal.

According to the present invention, in the optical ADM network having the above-mentioned mechanism, the occurrence of a failure on a certain path (optical transmission fiber) is detected by the adjacent optical ADM device, and further downstream is notified, and the failure location is detected. As a method for making a detour, the optical signal λosc for the optical supervisory channel is used.
I am trying to use.

That is, in the case of performing network protection for a 4-fiber-optical ring network system having two lines for service and two lines for protection, an electrical signal is generated in a node of the network to indicate a failure in a fiber as an optical transmission line. It is possible to monitor at the optical signal level without converting to the level.

That is, in the present embodiment, therefore, in addition to the use wavelengths λ0 to λn of the multiplexed optical signal Σλ of the transmission target data to be optically multiplexed and transmitted, other wavelengths far apart from these wavelengths are used. The optical signal λosc is sent from the node to the optical transmission line as an optical signal for monitoring, and is used for monitoring at the downstream node.

That is, it is the optical supervisory channel light source 27 of the optical transmission device 100 that constitutes a node that generates this supervisory signal, and the optical supervisory channel optical signal λosc generated from this optical supervisory channel light source 27 is It is given to the multiplexer 23 of the optical transmission device 100 at that node.

Now, if the service line in the network is normal, the service fibers 10-1 and 10
-2 only the multiplexed optical signal Σλ of the data to be transmitted
Is transmitted. Therefore, in this state, WEST
The multiplexed optical signal Σλ is sent to the fiber 10-2 on the SRV side via the wavelength demultiplexing unit 1-1 and to the fiber 10-1 on the EAST SRV side via the wavelength demultiplexing unit 1-3. Will be.

The multiplexed optical signal Σλ is WES
On the T SRV side, when it is output from the wavelength demultiplexing unit 1-1, it enters the optical multiplexer 23 on the WEST SRV side, where it is multiplexed with the optical signal for optical monitoring channel λosc from the optical monitoring channel light source 27. . Then, the multiplexed optical signal is sent to the downstream node via the fiber 10-2. Similarly, the wavelength demultiplexing unit 1-3 is also provided.
On the EAST SRV side, the multiplexed optical signal from EAST SV is output from the wavelength demultiplexing unit 1-3.
The light enters the optical multiplexer 23 on the RV side, and is multiplexed there with the optical signal for optical monitoring channel .lambda.osc from the optical monitoring channel light source 27. Then, the multiplexed optical signal is sent to the downstream node via the fiber 10-1.

In this way, the optical signal for optical supervisory channel λosc from the optical supervisory channel light source 27 is multiplexed (Σλ + λosc) with the multiplexed optical signal Σλ as the main signal to be transmitted and transmitted to the downstream side node. It In the optical transmission device 100 of the downstream side node, this combined optical signal (Σλ + λosc) is transmitted via the fiber 10-2 on the EASTSRV side.
However, there is an optical branching device 21 at the entrance, and at the stage of passing therethrough, the optical signal for optical monitoring channel λos
c is branched, the optical signal for optical supervisory channel λosc is sent to the OSC monitoring unit 22, and the remaining unmultiplexed multiplexed optical signal Σλ (main signal) is sent to the wavelength demultiplexing unit 1-3. To be

On the WEST SRV side, the combined optical signal (Σ) from the upstream side is transmitted via the fiber 10-1.
λ + λosc), but an optical branching device 21 is provided at the entrance, and the optical supervisory channel optical signal λosc is branched at the stage of passing therethrough, and the optical supervisory channel optical signal λo
sc is sent to the OSC monitoring unit 22, and the remaining multiplexed optical signal Σλ (main signal) that has not been branched is sent to the wavelength demultiplexing unit 1-1.

The OSC monitor 22 monitors the optical signal λosc for the optical supervisory channel, and does not issue an alarm if it is received normally. However, the optical supervisory channel optical signal λosc is "disconnected" or the optical supervisory channel optical signal λosc
If the AIS flag included in is abnormal ("1"), an alarm is output. This alarm is an optical branching device 21 to be monitored, where the optical signal on the optical monitoring channel is on the WEST side.
If it is from, it will be an alarm of the West side abnormality,
Further, if the optical supervisory channel optical signal to be monitored is from the optical branching device 21 on the EAST side, the tributary interface units 6-1-1 and 6-1-1-3 are distinguished as an ESAT side abnormal alarm. Given to.

Accordingly, the tributary interface units 6-1-1 and 6-1-1-3 which have received this give it to the optical switch 25 of their own.

Then, the optical switch 25 performs a switching operation by this alarm, and instead of the optical signals from the tributary switch units 5-1-1 to 5-1-2 located on the upstream side, the AIS pattern optical signal source 26 Switch to the signal path from the side. By this switching, the AIS pattern optical signal source 2
The optical signal of the AIS pattern from 6 flows to the tributary side (that is, the SDH (Synchronous Digital Hierarchy) device side) through the tributary interface I / F.

Therefore, this AIS is set on the tributary side.
It is possible to know from the optical signal of the pattern that a failure has occurred in the upstream line.

As described above, the above-mentioned alarm is an alarm of an abnormality in the WEST side if the optical signal of the optical supervisory channel to be monitored is from the optical branching device 21 on the WEST side. If the signal is from the optical branching device 21 on the EAST side, the tributary interface unit 6 distinguishes it as an alarm of an abnormality on the ESAT side.
-1-1 to 6-1-3, the tributary interface section 6-1-1 to 6-1 receives this.
-1-3, if it is an alarm from the WEST side, WE
The drop connection from the ST side is replaced with the optical signal of the AIS pattern, and in the case of an alarm from the EAST side, the drop connection from the EAST side is controlled to be replaced with the optical signal of the AIS pattern while controlling the optical signal. The switch 25 will be switched.

As a result, when a failure occurs in the line, the abnormality on the failure occurrence side can be detected on the tributary side by the AIS pattern.

On the other hand, the tributary interface units 6-1-1 and 6-1-3 to which the alarm is given also give this alarm to the monitor control unit 30. for that reason,
The supervisory control unit 30 controls the optical supervisory channel light source 27 to generate the optical supervisory channel optical signal λosc in which the AIS flag “1” at the time of abnormality is inserted in the transmission frame.

As a result, the optical supervisory channel light source 27 generates the optical supervisory channel optical signal λosc in which the AIS flag "1" at the time of abnormality is inserted into the transmission frame, and outputs it to the optical multiplexer 23 on the EAST side and the optical multiplexer on the WEST side. Give to the wave instrument 23.

Therefore, the optical multiplexer 23 adds the optical supervisory channel optical signal λosc having the AIS flag "1" to the wavelength multiplexed optical signals output from the wavelength demultiplexing units 1-1 and 1-3, respectively. Corresponding fiber 10
Send it to -1, 10-2.

In the downstream node receiving this, the optical supervisory channel optical signal λosc is branched by the optical branching device 21 of the optical transmission device 100 constituting the node and given to the OSC monitoring section 22 of its own.

The OSC monitoring unit 22 monitors the optical signal for optical monitoring channel λosc. Therefore, the optical signal for optical monitoring channel λosc becomes “off”, or the AIS flag included in the optical signal for optical monitoring channel λosc is detected. If it is abnormal (“1”), an alarm is output.

In this case, the AIS flag included in the optical supervisory channel optical signal λosc from the upstream is abnormal ("1"). Therefore, the OSC monitoring unit 22 issues an alarm.

This alarm is an alarm of an abnormality on the WEST side if the optical signal of the optical monitoring channel to be monitored is from the optical branching device 21 on the WEST side, and the optical signal of the optical monitoring channel to be monitored is on the EAST side. Optical splitter 21
If it is from, it is an ESAT side abnormal alarm,
Differently, the tributary interface unit 6-1-1, ...
6-1-3.

Accordingly, the tributary interface sections 6-1-1 to 6-1-3 which receive this give it to the own optical switch 25.

Then, the optical switch 25 performs the switching operation corresponding to the ESAT side and the west side by this alarm, and the tributary switch units 5-1-1 to 5--5 located on the upstream side.
Instead of the optical signal from 1-2, the signal path from the AIS pattern optical signal source 26 side is switched. By this switching, the AIS pattern optical signal from the AIS pattern optical signal source 26 flows to the tributary side via the tributary interface I / F.

Therefore, this AIS is set on the tributary side.
It is possible to know from the optical signal of the pattern that a failure has occurred in the upstream line.

Therefore, as shown in FIG. 4, for example, Sta
counterclockwise service fiber 10 from the terminal accommodated in the node at position A to the terminal accommodated at the node at station C by optical multiplexing.
When data is transmitted at -1, Stati
If a failure of the transmission path occurs in the service fiber 10-1 between the node at the position A on A and the node at the position E, the optical supervisory channel optical signal λosc will be interrupted. Station
It will be detected by the physical phenomenon called λosc optical signal disconnection at the node at position E, and the optical supervisory channel optical signal λosc having the AIS flag indicating the abnormality (“1”) will be generated downstream from here. By doing so, the node at the position of Station D can know that a transmission path failure has occurred upstream, and the node at the position of Station D is abnormal (“1”) downstream. By transmitting the optical supervisory channel optical signal λosc having the AIS flag indicating that
At the node at the position of ation C, a transmission line failure (line failure) has occurred in the service fiber 10-1 from the optical supervisory channel optical signal λosc having the AIS flag indicating the abnormality (“1”). You can know. Moreover, during that time, the optical signal can be directly monitored as it is without being converted into an electrical signal, and a mechanism for detecting and transmitting the occurrence of a failure without an optical-electrical conversion will be established. .

It should be noted that, for example, an SDH device is connected as a tributary side to the optical transmission device 100 in each node, and when the SDH devices in each of these nodes are normal, a fiber on the service side is used to specify each. Data is transmitted and received as an optical signal with the wavelength λ. The SDH device performs a digital transmission multiplexing process, processes a tributary signal handled on the tributary side, and transmits / receives transmission data by an optical signal of a specific wavelength λ. Further, when a failure is detected (when an error in transmission data is detected), an error detection signal is sent to the optical transmission apparatus 100 accommodated in the SDH apparatus, which is not shown. Have the function to Therefore, the monitoring controller 30 of the optical transmission device 100
Is an AIS pattern generated by the tributary interface units 6-1, 6-1-2, and 6-1-3 housed in the own optical transmission device 100, an alarm given from the OSC monitoring unit 22, or A error detection above. By receiving the signal, the generation of the AIS signal of "1" of the optical monitoring channel light source 27 can be controlled.

As described above, in the alarm generated by the OSC monitoring unit 22, the optical monitoring channel optical signal to be monitored is the W signal.
If it is from the optical branching device 21 on the EST side, it is an alarm of an abnormality on the WEST side, and if the optical supervisory channel optical signal to be monitored is from the optical branching device 21 on the EAST side, it is an alarm of an abnormal condition on the ESAT side. Are separately provided to the tributary interface units 6-1-1 to 6-1-3. Therefore, the tributary interface units 6-1-1 to 6-1-3 which receive the tributary interface units 6-1-1 to 6-1-3 receive the WEST side. If the alarm is from, the drop connection from the WEST side should be replaced with the optical signal of the AIS pattern, and if the alarm from the EAST side, the drop connection from the EAST side should be replaced with the optical signal of the AIS pattern. The optical switch 25 is switched while controlling. This allows the tributary side to detect the occurrence of a line failure by the AIS pattern.

On the other hand, the tributary interface units 6-1-1 and 6-1-3 to which the alarm is given also give this alarm to the monitor control unit 30. for that reason,
The supervisory control unit 30 controls the optical supervisory channel light source 27 to generate the optical supervisory channel optical signal λosc in which the AIS flag “1” at the time of abnormality is inserted in the transmission frame.

As a result, the optical supervisory channel light source 27 generates the optical supervisory channel optical signal λosc in which the AIS flag "1" at the time of abnormality is inserted into the transmission frame, and outputs it to the optical multiplexer 23 on the EAST side and the optical multiplexer on the WEST side. Give to the wave instrument 23.

Therefore, these multiplexers 23 add the optical supervisory channel optical signal λosc having the AIS flag "1" to the wavelength division multiplexed optical signals output from the wavelength division multiplexers 1-1 and 1-3, respectively. Corresponding fiber 10-
Send to 1, 10-2.

In this manner, the occurrence of a line failure is transmitted to the nodes downstream of the network one after another. Since the transmission lines are prepared for the clockwise direction and the counterclockwise direction respectively, it is possible to notify the occurrence of the line failure to all the nodes including the nodes on both sides of the transmission line where the line is disconnected.

At the node immediately downstream of the line disconnection position, the OSC monitor 22 detects that the optical supervisory channel optical signal λosc from the adjacent upstream node is disconnected. , It is also possible to notify the line disconnection by using the reverse line (fiber), and by controlling the switching to the detour between the adjacent nodes sandwiching the faulty section, it is possible to perform the optical signal transmission while avoiding the fault. .
When the transmission line cannot be secured by the service fiber pair, the protection fiber pair 10-
The optical signal is transmitted by switching to 3 and 10-4. Even for protection, since it has the same functional elements as above, it is possible to monitor the line failure at the optical level, detect the line failure occurrence, transmit it to the downstream side, and perform the optical transmission by bypassing the failure point. What can be done is the same as described above.

As described above in detail, the present invention enables the protection control only by the optical level in the optical transmission technique using the optical wavelength division multiplexing technique (ADM). An optical transmission device using an ADM allocates an SDH (Synchronous Digital Hierarchy) signal from the tributary side to an optical wavelength channel, performs optical multiplexing, and performs optical transmission, and is attracting attention as a high-speed and large-capacity communication technology. .

The optical signal of the data transmitted and received between the terminals is not processed by an electric signal but is processed in the unit of wavelength path as the optical signal. As a result, in the case of electric signal processing, high-speed processing, which becomes difficult, becomes possible, and the transmission speed can be improved. However, the end-to-to
-Because it is transmitted by End, even if the optical signal is interrupted due to a transmission path failure in the middle segment, the noise component optical signal obtained by amplifying the noise component with the optical amplifier is sent to the downstream side, and Since an optical signal is being sent to the device, the failure cannot be detected and the AIS of the SDH signal cannot be sent to the lower tributary side.

In order to solve this problem, the present invention is configured so that an OSC (optical supervisory channel) frame used for ring protection control includes an AIS flag for each wavelength and transmits an optical signal of this optical supervisory channel. The light having a wavelength different from that of the optical multiplexed signal of data is transmitted from each node to the downstream side of the transmission line, and each node branches the optical signal of this optical monitoring channel from the optical multiplexed signal and monitors it. For the upstream transmission line disconnection failure, the optical signal is cut off to the tributary side and the AIS pattern is given instead to notify the line failure, and the optical monitoring channel is provided to the downstream side of the transmission line. The optical signal with the AIS flag set is transmitted, and in the downstream side node, a line failure occurs on the upstream side of the transmission line due to the AIS flag of the optical signal of the optical monitoring channel. It was to be able to know that.

Particularly in the present invention, the optical monitoring channel (OS
C) is used, and the optical signal of this optical supervisory channel whose wavelength is different from that of the main signal for easy separation is multiplexed with the main signal for transmission, and the state of the optical signal of this optical supervisory channel is used. I was able to know the state of the line from. The optical signal of the optical monitoring channel is prepared for directly monitoring the signal disconnection and the signal deterioration at the optical level. Since there is a monitoring channel called OSC, the AIS signal (for example, The abnormality detection signal by AIS is made to be a continuous signal of "1") so that the failure occurrence can be transmitted. Moreover, the OSC signal, which is a monitoring signal, is assigned a completely different wavelength from that for the main signal, and by transmitting the signal of the specific pattern as the optical signal of the specific wavelength, the signal is transmitted on the downstream side of the transmission line. It is possible to monitor the deterioration and the signal disconnection from the signal state of the pattern. Therefore, if a transmission line failure occurs and an optical signal is interrupted, this can be immediately detected, and reliable high-speed transmission that enables continuous transmission using a detour for a line failure is realized. A possible optical transmission system can be provided.

The present invention is not limited to the examples shown in the above-described embodiments, but can be modified in various ways. Further, in the present invention, the embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some of the constituent elements are deleted from all the constituent elements shown in the embodiment, at least one of the problems described in the section of the problem to be solved by the invention can be solved and described in the section of the effect of the invention. When at least one of the effects described above is obtained, a configuration in which this constituent element is deleted can be extracted as an invention.

[0117]

As described above, the present invention provides a plurality of optical ADM devices,
In an optical transmission network in which service (current) and protection (spare) optical transmission lines are connected, and terminal devices accommodated in an optical ADM device are transmitted by optical signals of unique wavelengths. When a failure occurs in the device, it can be detected at the optical level, the failure can be transmitted to the downstream side at the optical level, and the AIS signal can be given to the terminal device. It is possible to provide a network technology that enables monitoring and transmission of a failure occurrence at the optical level and can back up the advantages of the large-capacity high-speed transmission of the optical multiplexing technology.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a network system configuration example to which the present invention is applied.

FIG. 2 is a block diagram showing an example of a node mounting an optical transmission device according to the present invention.

FIG. 3 is a block diagram showing a main configuration of the optical transmission device of FIG.

FIG. 4 is a diagram for explaining the present invention.

[Explanation of symbols]

1-1 ... Wavelength demultiplexing unit (WEST service system) 1-2 ... Wavelength demultiplexing unit (WEST protection system) 1-3 ... Wavelength demultiplexing unit (EAST service system) 1-4 ... Wavelength demultiplexing unit (EAST protection system) System) 2-1-1 ... Line interface unit (WEST service system) 2-1-2 ... Line interface unit (WEST protection system) 2-1-3 ... Line interface unit (EAST service system) 2-1-4. Line interface unit (EAST protection system) 3-1-1 ... Line switch unit (service system) 3-1-2 ... Line switch unit (protection system) 4-1 ... Optical cross-connect unit (service system) 4-2 ... Optical cross-connect unit (protection system) 5-1-1 ... Tributary switch unit (service system) 5-1-2 ... Tributary switch unit (protection system) 6-1-1 ... Tributary interface unit (service system) 6-1-2 ... Tributary interface unit (protection system) 6-1-3 ... Tributary interface unit (part-time system) 10 ... Optical fiber (optical transmission Path 10-1 ... Service (current) fiber (optical transmission path) 10-2 ... Protection (spare) fiber (optical transmission path) 20 ... Optical ADM section 21 ... Optical brancher 22 ... OSC monitoring section 23 ... Combiner 25 ... Optical switch 26 ... AIS pattern optical signal source 27 ... Optical monitoring channel light source 30 ... Monitoring control unit 100 ... Optical transmission device (optical ADM device) .lambda.osc ... Optical monitoring channel optical signal.

Claims (6)

[Claims] 1. A plurality of optical transmission devices using an optical ADM device,
An optical transmission network for connecting data through service (current) and protection (spare) optical transmission lines, and performing wavelength-multiplexed data transmission between end devices accommodated in an optical transmission device by optical signals of unique wavelengths. In the optical transmission device in, the optical supervisory channel optical signal generating means for generating an optical signal of the optical supervisory channel by the optical signal of a wavelength different from the optical signal used for wavelength multiplexing, and the optical from the optical supervisory channel optical signal generating means Of the optical signals transmitted through the transmission line, and a multiplexing unit that adds a signal to the wavelength-multiplexed optical signal and sends the signal to the transmission line,
An optical device comprising: an optical branching device for extracting an optical signal of the optical monitoring channel; and monitoring means for monitoring a transmission line fault from the optical signal of the optical monitoring channel branched by the optical branching device. Optical transmission equipment for transmission network systems. 2. A plurality of optical transmission devices using an optical ADM device,
An optical transmission network for connecting data through service (current) and protection (spare) optical transmission lines, and performing wavelength-multiplexed data transmission between end devices accommodated in an optical transmission device by optical signals of unique wavelengths. In the optical transmission device according to the present invention, the optical transmission device generates an optical signal of an optical monitoring channel by an optical signal having a wavelength different from that of an optical signal used for wavelength multiplexing, and an AIS signal is added when a line failure occurs. An optical supervisory channel optical signal generating means for generating an optical signal of the channel; a multiplexing means for adding the optical signal from the optical supervisory channel optical signal generating means to the wavelength-multiplexed optical signal and sending it to a transmission line; Of the optical signals transmitted through the transmission line,
An optical device comprising: an optical branching device for extracting an optical signal of the optical monitoring channel; and monitoring means for detecting a transmission line fault from the optical signal of the optical monitoring channel branched by the optical branching device. Optical transmission equipment for transmission network systems. 3. A plurality of optical transmission devices using an optical ADM device,
An optical transmission network for connecting data through service (current) and protection (spare) optical transmission lines, and performing wavelength-multiplexed data transmission between end devices accommodated in an optical transmission device by optical signals of unique wavelengths. In the optical transmission device according to the present invention, the optical transmission device generates an optical signal of an optical monitoring channel by an optical signal having a wavelength different from that of an optical signal used for wavelength multiplexing, and an AIS signal is added when a line failure occurs. An optical supervisory channel optical signal generating means for generating an optical signal of the channel; a multiplexing means for adding the optical signal from the optical supervisory channel optical signal generating means to the wavelength-multiplexed optical signal and sending it to a transmission line; Of the optical signals transmitted through the transmission line,
An optical branching device for extracting an optical signal of the optical monitoring channel, a monitoring unit for detecting a transmission line fault from the optical signal of the optical monitoring channel branched by the optical branching unit, and the monitoring unit for detecting a transmission line fault Then, the optical transmission device of the optical transmission network system, comprising: means for transmitting an AIS signal in place of data, to the terminal side accommodated in itself. 4. A plurality of optical transmission devices using an optical ADM device,
An optical transmission network for connecting data through service (current) and protection (spare) optical transmission lines, and performing wavelength-multiplexed data transmission between end devices accommodated in an optical transmission device by optical signals of unique wavelengths. In the transmission path failure monitoring method in the above, from the optical transmission apparatus on the upstream side of the optical transmission apparatus, an optical signal of an optical monitoring channel is generated by an optical signal having a wavelength different from an optical signal used for wavelength multiplexing, Transmission of an optical transmission network system characterized by transmitting to the transmission line, extracting the optical signal of the transmitted optical monitoring channel on the downstream side, and monitoring the transmission line failure from the state of the extracted optical signal Road obstacle monitoring method. 5. A plurality of optical transmission devices using an optical ADM device,
An optical transmission network for connecting data through service (current) and protection (spare) optical transmission lines, and performing wavelength-multiplexed data transmission between end devices accommodated in an optical transmission device by optical signals of unique wavelengths. In the transmission path failure monitoring method in, in the optical transmission device, from the upstream optical transmission device, while generating an optical signal of an optical monitoring channel by an optical signal of a wavelength different from the optical signal used for wavelength multiplexing, At the time of line failure, an optical signal of the optical monitoring channel to which the AIS signal is added is generated and transmitted to the transmission path, and the optical signal of the transmitted optical monitoring channel is extracted on the downstream side. A transmission line fault monitoring method for an optical transmission network system, which comprises monitoring a transmission line fault from a status. 6. A plurality of optical transmission devices using an optical ADM device,
An optical transmission network for connecting data through service (current) and protection (spare) optical transmission lines, and performing wavelength-multiplexed data transmission between end devices accommodated in an optical transmission device by optical signals of unique wavelengths. In the transmission path failure monitoring method in, in the optical transmission device, from the upstream optical transmission device, while generating an optical signal of an optical monitoring channel by an optical signal of a wavelength different from the optical signal used for wavelength multiplexing, When a line failure occurs, an optical signal of the optical monitoring channel to which an AIS signal is added is generated and transmitted to the transmission line, and the optical signal of the transmitted optical monitoring channel is extracted on the downstream side, and the extracted optical signal is extracted. The optical transmission network is characterized in that the transmission line fault is monitored from the above state, and when the transmission line fault is detected, the AIS signal is sent to the terminal side that accommodates itself in place of the data. Network system failure monitoring method.