JPWO2015008512A1 - Transmission apparatus, transmission system, and path switching method - Google Patents

Abstract

Provided is a transmission device capable of solving the problem that the scale and cost of a communication device increase. The optical monitoring units 331A and 331B are provided corresponding to each of a plurality of paths for transmitting a wavelength multiplexed signal in which a plurality of optical wavelength signals having different wavelengths are combined, and the wavelength multiplexed signals transmitted through the corresponding path Alternatively, the optical level of the optical wavelength signal included in the wavelength multiplexed signal is detected. The switching unit 332 selects any one of a plurality of paths, and outputs a wavelength multiplexed signal transmitted through the selected path or an optical wavelength signal included in the wavelength multiplexed signal as an optical signal. The signal processing unit 333 detects a failure occurring in each path based on the light level detected by the light monitoring units 331A and 331B and the optical signal output from the switching unit 332, and according to the detection result. The path selected by the switching unit 332 is switched.

Description

  The present invention relates to a transmission apparatus that performs transmission of an optical signal, and more particularly to a wavelength division multiplexing transmission apparatus that supports a line redundancy system capable of switching paths in order to avoid a failure.

  In the field of optical communication, a line redundancy method is known as a method for improving the reliability related to transmission of a WDM (Wavelength Division Multiplexing) signal so as to avoid a failure by switching a route for transmitting the WDM signal. Yes.

  In the line redundancy system, a wavelength multiplexing transmission apparatus serving as a receiving end that receives a WDM signal usually detects a path failure. Specifically, a wavelength division multiplex transmission apparatus at a receiving end that receives a WDM signal monitors each input optical level of an optical wavelength signal in a WDM signal input from each of a plurality of paths using an optical monitoring apparatus. Based on the monitoring result, it is detected whether or not the optical wavelength signal is blocked. When the optical wavelength signal in the WDM signal input from the currently used operation path is interrupted, the wavelength division multiplexing transmission apparatus determines that a failure has occurred in the operation path, and transmits the WDM signal. The transmission route is switched from the active route to the standby route.

  However, the above line redundancy method only detects a failure based on the input light level, so it cannot monitor the frame error or bit error of the optical signal, and cannot accurately detect the failure. There's a problem.

  On the other hand, Patent Document 1 discloses a communication device that can detect a frame error and a bit error of an optical signal. The communication apparatus includes a plurality of optical couplers provided corresponding to each of a plurality of paths, and a plurality of monitoring devices provided corresponding to each of the plurality of paths. The one optical signal is branched, one is output to a predetermined route, and the other is input to the monitoring device corresponding to its own route. Each monitoring device analyzes the input optical signal and detects a frame error or a bit error.

JP 2000-151607 A

  However, the communication device described in Patent Document 1 has a problem that the scale and cost of the communication device increase because a monitoring device for analyzing an optical signal must be provided for each path.

  Note that in a general line redundancy system, a relay optical wavelength converter that performs regenerative relay processing on a WDM signal may be provided on the path. When a failure occurs in the path on the input side of the optical wavelength conversion unit, the optical wavelength conversion unit that performs regenerative repeat processing in the optical wavelength conversion device for relay correctly corrects the failure with the optical wavelength multiplexing transmission device at the receiving end. In order to be able to detect, it is necessary to block the WDM signal transmitted through the path in which the failure has occurred and lower the input light level detected by the optical monitoring unit of the optical wavelength division multiplex transmission apparatus at the receiving end. However, when the WDM signal is cut off, a plurality of optical wavelength signals included in the WDM signal are cut off at the same time, so that the input optical level of the WDM signal input to the optical wavelength multiplexing transmission device at the receiving end changes rapidly. There was a concern of affecting WDM signals transmitted through other routes.

  In addition, a general wavelength multiplexing transmission apparatus extracts an optical wavelength signal that needs to be converted from a WDM signal, and outputs it to an optical wavelength conversion unit that converts the wavelength of the extracted optical wavelength signal. In recent years, there has been proposed a wavelength division multiplexing transmission apparatus that outputs a WDM signal as it is to an optical wavelength converter. In this case, the WDM signal is input as it is to the optical monitoring device that monitors the optical level, and even when a specific optical wavelength signal is blocked, the blockage is detected due to the influence of other optical wavelength signals. There are concerns that cannot be made.

  The communication device described in Patent Document 1 does not consider these concerns.

  An object of the present invention is to provide a transmission apparatus, a transmission system, and a path switching method that can solve at least the problem that the scale and cost of the communication apparatus increase.

  A transmission apparatus according to the present invention is provided with a plurality of paths corresponding to a plurality of paths for transmitting wavelength multiplexed signals in which a plurality of optical wavelength signals having different wavelengths are combined, and the wavelength multiplexed signals transmitted through the corresponding paths. Alternatively, an optical monitoring unit that detects an optical level of an optical wavelength signal included in the wavelength multiplexed signal, and any one of the plurality of paths is selected, and the wavelength multiplexed signal or the wavelength multiplexed signal transmitted through the selected path is selected. Based on the switching unit that outputs the included optical wavelength signal as an optical signal, the light level detected by the optical monitoring unit, and the optical signal output from the switching unit, a fault that has occurred in each path is detected. A signal processing unit that switches a path selected by the switching unit according to the detection result.

  The transmission system according to the present invention is provided with a plurality of paths corresponding to each of a plurality of paths for transmitting wavelength multiplexed signals in which a plurality of optical wavelength signals having different wavelengths are combined, and the wavelength multiplexed signals transmitted through the corresponding paths. Alternatively, an optical monitoring unit that detects an optical level of an optical wavelength signal included in the wavelength multiplexed signal, and any one of the plurality of paths is selected, and the wavelength multiplexed signal or the wavelength multiplexed signal transmitted through the selected path is selected. Based on the monitoring result of the optical level by the optical monitoring unit and the optical signal output from the switching unit, a failure occurring in each path is detected based on the switching unit that outputs the included optical wavelength signal as an optical signal. A signal processing unit that switches a route selected by the switching unit according to the detection result, and a plurality of relay transmission devices belonging to each of the plurality of routes It has a.

  The path switching method according to the present invention detects the optical level of a wavelength multiplexed signal in which a plurality of optical wavelength signals having different wavelengths transmitted through each of a plurality of paths are combined or an optical wavelength signal included in the wavelength multiplexed signal. Selecting one of the plurality of paths, outputting a wavelength multiplexed signal transmitted through the selected path or an optical wavelength signal included in the wavelength multiplexed signal as an optical signal, and detecting the detected optical level; Based on the output optical signal, a failure occurring in each path is detected, and the selected path is switched according to the detection result.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to suppress the increase in the scale and cost of a communication apparatus.

It is a figure which shows the wavelength division multiplexing transmission system of one Embodiment of this invention. It is a figure for demonstrating an example of operation | movement of the wavelength division multiplexing transmission system of one Embodiment of this invention. It is a figure for demonstrating the other example of operation | movement of the wavelength division multiplexing transmission system of one Embodiment of this invention. It is a figure for demonstrating the other example of operation | movement of the wavelength division multiplexing transmission system of one Embodiment of this invention. It is a figure for demonstrating the other example of operation | movement of the wavelength division multiplexing transmission system of one Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, components having the same function may be denoted by the same reference numerals and description thereof may be omitted.

  FIG. 1 is a diagram showing a wavelength division multiplexing transmission system according to an embodiment of the present invention. The wavelength multiplexing transmission system shown in FIG. 1 is a transmission system that transmits WDM signals, and includes wavelength multiplexing transmission apparatuses 1 to 4. In FIG. 1, the WDM signal is transmitted from the wavelength division multiplexing transmission apparatus 1 to the wavelength division multiplexing transmission apparatus 3. The path from the wavelength division multiplexing transmission apparatus 1 to the wavelength division multiplexing transmission apparatus 3 includes a path A where the wavelength division multiplexing transmission apparatus 2 is interposed and a path B where the wavelength division multiplexing transmission apparatus 4 is interposed.

  The wavelength division multiplexing transmission apparatus 1 is a transmission apparatus serving as a transmission end that transmits a WDM signal. The wavelength multiplexing transmission apparatus 1 includes a plurality of optical wavelength conversion units 11, optical wavelength multiplexing units 12A and 12B, wavelength monitoring units 13A and 13B, a monitoring control unit 14, and optical monitoring control units 15A and 15B.

  The plurality of optical wavelength conversion units 11 and the monitoring control unit 14 have a configuration common to the paths A and B, and the optical wavelength multiplexing unit 12A, the wavelength monitoring unit 13A, and the optical monitoring control unit 15A correspond to the path A. The optical wavelength multiplexing unit 12B, the wavelength monitoring unit 13B, and the optical monitoring control unit 15B are configurations corresponding to the path B.

  Each optical wavelength converter 11 receives a client signal that is an optical signal having a specific wavelength from a client device (not shown) such as a router. Each optical wavelength converter 11 converts the wavelength of the inputted client signal into a wavelength for WDM signal, and outputs the client signal obtained by converting the wavelength as an optical wavelength signal. In addition, the wavelength of the optical wavelength signal which each optical wavelength conversion part 11 outputs differs from each other.

  Specifically, each optical wavelength conversion unit 11 includes a signal processing unit 111 and a coupler unit 112.

  A client signal is input to the signal processing unit 111. The signal processing unit 111 converts the wavelength of the input client signal into a wavelength for the WDM signal, and outputs the client signal obtained by converting the wavelength as an optical wavelength signal.

  The coupler unit 112 branches the optical wavelength signal output from the signal processing unit 111 into two, outputs one optical wavelength signal to the optical wavelength multiplexing unit 12A of the path A, and transmits the other optical wavelength signal of the path B. It outputs to the optical wavelength multiplexing part 12B.

  The optical wavelength multiplexer 12A multiplexes the optical wavelength signals output from the optical wavelength converters 11 to generate a WDM signal obtained by multiplexing the optical wavelength signals, and outputs the generated WDM signal. .

  The wavelength monitoring unit 13A detects each wavelength of the optical wavelength signal included in the WDM signal generated by the optical wavelength multiplexing unit 12A, and notifies the optical monitoring control unit 15A of the wavelength via the monitoring control unit 14. Specifically, the wavelength monitoring unit 13A, for each wavelength of all the optical wavelength signals that can be included in the WDM signal, has its wavelength included in the WDM signal generated by the optical wavelength multiplexing unit 12A. Whether the wavelength actually exists is detected.

  The monitoring control unit 14 detects a failure that occurs in each optical wavelength conversion unit 11, and notifies the failure to the optical monitoring control units 15A and 15B.

  The optical supervisory control unit 15A generates an optical supervisory signal indicating the wavelength and the failure notified from each of the wavelength supervisory part 13A and the supervisory controller 14, and the optical supervisory signal is output from the optical wavelength multiplexer 12A. Are combined and output.

  The optical wavelength multiplexing unit 12B, the wavelength monitoring unit 13B, and the optical monitoring control unit 15B have the same functions as the optical wavelength multiplexing unit 12A, the wavelength monitoring unit 13A, and the optical monitoring control unit 15A. The same processing as that performed by the optical wavelength multiplexing unit 12A, the wavelength monitoring unit 13A, and the optical monitoring control unit 15A is performed on the WDM signal output to.

  The wavelength division multiplexing transmission device 2 is a relay transmission device that relays WDM signals. The wavelength multiplexing transmission apparatus 2 includes a wavelength monitoring unit 21, an optical wavelength separation unit 22, a plurality of optical wavelength conversion units 23, an optical wavelength multiplexing unit 24, a wavelength monitoring unit 25, a monitoring control unit 26, and an optical monitoring. And a control unit 27.

  The wavelength monitoring unit 21 detects each wavelength of the optical wavelength signal included in the WDM signal output from the wavelength multiplexing transmission apparatus 1 and notifies the optical monitoring control unit 27 of the wavelength via the monitoring control unit 26. Specifically, for each wavelength of all optical wavelength signals that can be included in the optical wavelength multiplexed signal, the wavelength monitoring unit 21 includes the wavelength in the WDM signal output from the wavelength multiplexing transmission device 1. It is detected whether it actually exists as the wavelength of the optical wavelength signal.

  The optical wavelength demultiplexing unit 22 demultiplexes the WDM signal output from the wavelength division multiplex transmission device 1 into an optical wavelength signal and an optical monitoring signal included in the WDM signal and outputs the demultiplexed signals. At this time, the optical wavelength separation unit 22 outputs the optical monitoring signal to the monitoring control unit 26 and outputs each of the optical wavelength signals to each optical wavelength conversion unit 23.

  Each optical wavelength converter 23 may be called a regenerative repeater. Each optical wavelength converter 23 corresponds to each wavelength of the optical wavelength signal, performs regenerative relay processing on the optical wavelength signal having the corresponding wavelength, and outputs the optical wavelength signal subjected to the regenerative relay processing. The regenerative relay process is, for example, a 3R relay process. Note that the 3R relay processing includes equalization (Reshaping) processing, retiming processing, and identification regeneration (Regenerating) processing.

  In addition, each optical wavelength conversion unit 23 performs a detection process for detecting a failure that has occurred in the path A based on an optical wavelength signal having a corresponding wavelength.

  When a failure is detected in the detection process, each optical wavelength conversion unit 23 outputs an alarm signal indicating the failure as an optical wavelength signal, or the optical monitoring control unit 26 detects the failure via the monitoring control unit 26. Notification processing to notify 27 is performed. More specifically, in each optical wavelength converter 23, the path A to which the wavelength division multiplexing transmission device 2 belongs is an active path that is currently used for transmission of WDM signals, or a fault occurs in the active path. A route flag indicating whether the route is a standby route to be switched when an error occurs is set. Each optical wavelength conversion unit 23 performs output processing when the route flag indicates an active route, and performs notification processing when the route flag indicates a standby route. The alarm signal output in the output process is an AIS (alarm indication signal) signal or a signal corresponding thereto, and is preferably a signal having a wavelength corresponding to the optical wavelength converter 23.

  The optical wavelength multiplexer 24 multiplexes the optical wavelength signals output from the optical wavelength converters 23 to generate a WDM signal obtained by multiplexing the optical wavelength signals, and outputs the generated WDM signal. .

  The wavelength monitoring unit 25 detects each wavelength of the optical wavelength signal included in the WDM signal generated by the optical wavelength multiplexing unit 24 and notifies the optical monitoring control unit 27 of the wavelength via the monitoring control unit 26. Specifically, for each wavelength of all optical wavelength signals that can be included in the WDM signal, the wavelength monitoring unit 25 has an optical wavelength signal whose wavelength is included in the WDM signal generated by the optical wavelength multiplexing unit 12A. It is detected whether or not it exists as a wavelength.

  Based on the optical monitoring signal from the optical wavelength demultiplexing unit 22, the monitoring control unit 26 detects a failure that has occurred in the wavelength multiplexing transmission apparatus 1 and notifies the optical monitoring control unit 27 of the failure. Also, the supervisory control unit 26 receives setting information indicating whether the path A is the active system from the wavelength division multiplex transmission apparatus 3, and changes the path flag set in each optical wavelength conversion unit 23 based on the information. To do.

  The optical monitoring control unit 27 generates an optical monitoring signal indicating a failure and a wavelength notified from each of the optical wavelength conversion units 23, the wavelength monitoring unit 25, and the monitoring control unit 26, and the optical monitoring signal is transmitted to the optical wavelength multiplexing unit. The signal is combined with the WDM signal output from 12A and output.

  The wavelength division multiplexing transmission device 4 is a relay transmission device that relays WDM signals. The wavelength multiplexing transmission device 4 includes a wavelength monitoring unit 41, an optical wavelength separation unit 42, a plurality of optical wavelength conversion units 43, an optical wavelength multiplexing unit 44, a wavelength monitoring unit 45, a monitoring control unit 46, and an optical monitoring control. Part 47. Each part of the wavelength division multiplexing transmission device 4 has the same function as that of the configuration of the same name of the wavelength division multiplexing transmission device 2, and performs the same processing as the configuration of the same name on the WDM signal transmitted through the path B. Do.

  The wavelength division multiplex transmission device 3 is a transmission device serving as a receiving end of the WDM signal. The wavelength multiplexing transmission apparatus 3 includes optical monitoring control units 31A and 31B, optical wavelength separation units 32A and 32B, a plurality of optical wavelength conversion units 33, and a monitoring control unit 34.

  The optical monitoring control unit 31A and the optical wavelength separation unit 32A have a configuration corresponding to the path A, and the optical monitoring control unit 31B and the optical wavelength separation unit 32B have a configuration corresponding to the path B. The control unit 34 has a configuration common to the routes A and B.

  The optical supervisory control unit 31A is an acquisition unit that acquires an optical supervisory signal from the WDM signal output from the wavelength division multiplex transmission apparatus 2. The optical monitoring control unit 31A notifies the optical wavelength conversion unit 33 of the failure and wavelength indicated by the acquired optical monitoring signal via the monitoring control unit 34.

  The optical wavelength demultiplexing unit 32A demultiplexes the WDM signal output from the wavelength division multiplex transmission device 2 into an optical wavelength signal and an optical monitoring signal included in the WDM signal, and each of the demultiplexed optical wavelength signals. Output to the optical wavelength converter 33.

  The optical supervisory control unit 31B and the optical wavelength demultiplexing unit 32B have the same functions as the optical supervisory control unit 31A and the optical wavelength demultiplexing unit 32B, and for the WDM signal that transmits the path B output from the wavelength division multiplexing transmission device 2 Then, the same processing as that of the optical monitoring control unit 31B and the optical wavelength separation unit 32B is performed.

  Each optical wavelength converter 33 corresponds to each of the wavelengths of the optical wavelength signal, and receives the optical wavelength signal having the corresponding wavelength from both the optical wavelength separators 32A and 32B. Each optical wavelength converter 33 selects one of paths A and B, and an optical wavelength signal demultiplexed from the WDM signal transmitted through the selected path, that is, optical wavelength separation corresponding to the selected path. The optical wavelength signal received from the unit 32A or 32B is output as a client signal to a client device (not shown).

  Specifically, each optical wavelength conversion unit 33 includes optical monitoring units 331A and 331B, a switching unit 332, and a signal processing unit 333. The optical monitoring unit 331A has a configuration corresponding to the path A, and the optical monitoring unit 331B has a configuration corresponding to the path B.

  The optical monitoring unit 331A detects the optical level of the optical wavelength signal received from the optical wavelength separation unit 32A, and outputs the optical level to each signal processing unit 333 via the monitoring control unit 34.

  The optical monitoring unit 331B detects the optical level of the optical wavelength signal received from the optical wavelength separation unit 32B, and outputs the optical level to each signal processing unit 333 via the monitoring control unit 34.

  The switching unit 332 selects one of the paths A and B, and outputs an optical wavelength signal demultiplexed from the wavelength multiplexed signal transmitted through the selected path.

  The signal processing unit 333 converts the wavelength of the optical wavelength signal output from the switching unit 332 into a wavelength for the client device, and outputs the converted optical wavelength signal to the client device. Since the optical wavelength signal in the wavelength multiplexed signal transmitted through the path selected by the switching unit 332 is output to the client device, the path selected by the switching unit 332 is the active system path. Become.

  Further, the signal processing unit 333 is based on the failure and wavelength notified from the optical monitoring control units 31A and 31B, the optical level notified from the optical monitoring units 331A and 331B, and the optical wavelength signal output from the switching unit 332. Thus, the failure occurring in each of the routes A and B is detected, and the route selected by the switching unit 332 is switched based on the detection result. At this time, the signal processing unit 333 sets the route selected by the switching unit 332 as an active route, sets the route not selected by the switching unit 332 as a standby route, and indicates the setting. The setting information is notified to the monitoring control unit 34.

  Specifically, the signal processing unit 333 detects a failure that has occurred in the operation system path based on the optical wavelength signal output from the switching unit 332. At this time, the signal processing unit 333 determines whether or not the optical wavelength signal is an alarm signal. If the optical wavelength signal is an alarm signal, the signal processing unit 333 determines that a failure has occurred in the operation path. If the optical wavelength signal is not an alarm signal, the optical wavelength signal is analyzed to detect whether the optical wavelength signal has an error (for example, at least one of a frame error and a bit error). It is determined that a failure has occurred on the active route. Note that the signal processing unit 333 may use not only the optical wavelength signal but also the information notified from the optical monitoring control unit and the optical monitoring unit corresponding to the path of the active system for detection of the failure.

  On the other hand, since the standby path is not connected to the standby path to each signal processing unit 333, it is different from the failure detection by the active path A.

  Specifically, the signal processing unit 333 determines the light level notified from the optical monitoring unit corresponding to the standby path and the failure and wavelength notified from the optical monitoring control unit 31A corresponding to the standby path. Based on this, a failure in the backup path is detected. For example, when the light level falls below a predetermined threshold, when a failure is notified from the light monitoring control unit 31A, or when the wavelength notified from the light monitoring control unit 31A no longer exists, the path of the standby system Detect faults.

  The monitoring control unit 34 notifies the setting information from each signal processing unit 333 to the monitoring control units 26 and 46 of the wavelength division multiplexing transmission apparatuses 2 and 4.

  In the present embodiment described above, the coupler unit 112 and the switching unit 332 are described as being provided inside the optical wavelength conversion units 11 and 33, but may be provided outside them. Further, in the present embodiment, the coupler unit that combines the WDM signal and the optical monitoring signal is described as being provided in the optical monitoring control units 15A, 15B, 27, and 47. However, the coupler unit may be provided outside them. Good.

  In addition, although only one optical wavelength conversion unit 23 and 43 is provided for each optical wavelength signal, it may not be provided or may be provided in multiple stages. Each of the wavelength division multiplexing transmission apparatuses 2 and 4 may be provided in multiple stages.

  Further, although the optical wavelength demultiplexing units 22, 42, 32A, and 32B output the WDM signal after separating it into the optical wavelength signal, the WDM signal may be output as it is. In this case, the switching unit 332 outputs the wavelength multiplexed signal transmitted through the selected path as it is. Therefore, the switching unit 332 selects any one of a plurality of paths, and outputs the wavelength multiplexed signal transmitted through the selected path or the optical wavelength signal included in the wavelength multiplexed signal as an optical signal.

  In the wavelength division multiplexing transmission system shown in FIG. 1, the WDM signal is transmitted in one direction from the wavelength division multiplexing transmission apparatus 1 to the wavelength division multiplexing transmission apparatus 3 in order to simplify the description. It is desirable that the WDM signal be configured to be bidirectional so that the WDM signal is transmitted from the wavelength division multiplexing transmission apparatus 3 to the wavelength division multiplexing transmission apparatus 1 as well.

  Next, the operation of the wavelength division multiplexing transmission system will be described.

  2 to 5 are diagrams for explaining the operation of the wavelength division multiplexing transmission system. In the following description, it is assumed that the route A is used as an active route and the route B is used as a standby route.

  In the above situation, when the path A is disconnected between the wavelength division multiplexing transmission apparatuses 1 and 2 as shown in FIG. 2, each optical wavelength conversion unit 23 of the wavelength division multiplexing transmission apparatus 2 generates an alarm signal to generate an optical signal. It outputs to the optical wavelength multiplexing part 24 as a wavelength signal. In this case, each signal processing unit 333 of the wavelength division multiplexing apparatus 3 detects that a failure has occurred in the path A because the optical wavelength signal is an alarm signal. In the example of FIG. 2, since no failure has occurred in the route B, each signal processing unit 333 switches the route selected by each switching unit 332 from the route A to the route B. As a result, it is possible to avoid a failure that has occurred in the route A.

  Next, the operation in the case where a failure has occurred in the backup path B will be described with reference to FIGS.

  In the example of FIG. 3, it is assumed that the path B is disconnected between the wavelength multiplexing transmission apparatuses 4 and 3, and then the path A is disconnected between the wavelength multiplexing transmission apparatuses 1 and 2 as in the example of FIG.

  In this case, first, when the path B is disconnected, the WDM signal transmitted through the path B is cut off, so that each optical monitoring unit 331B in the wavelength division multiplexing transmission device 3 performs each wavelength of the optical wavelength signal in the WDM signal. Is not detected, and this is notified to each signal processing unit 333 via the monitoring control unit 34. Each signal processing unit 333 recognizes that a failure has occurred in the path B based on the notified detection result. After that, when the route A is disconnected as described above, each signal processing unit 333 detects that a failure has occurred in the route A, as in the example of FIG. In this case, since a failure has occurred in the route B, each signal processing unit 333 does not switch the route selected by the switching unit 332.

  It is a general switching method in the line redundancy method that when a failure occurs in the standby route, even if a failure occurs in the active route, the route is not switched.

  In the example of FIG. 4, a failure occurs in the output unit of the optical wavelength conversion unit 43 of the wavelength division multiplex transmission apparatus 4, and thereafter, the path A is connected between the wavelength division multiplexing transmission apparatuses 1 and 2 as in the example of FIG. 2. It is said to have been disconnected.

  In this case, first, when a failure occurs in the output unit of the optical wavelength conversion unit 43 of the wavelength division multiplexing transmission device 4, the wavelength monitoring unit 45 in the wavelength division multiplexing transmission device 4 causes the optical wavelength conversion unit 43 in which the failure occurs in the output unit. The corresponding wavelength is not detected, and this is reflected in the optical monitoring signal output from the optical monitoring control unit 47. Thereby, the failure in the output unit of the optical wavelength conversion unit 43 is notified to the signal processing unit 333 of the optical wavelength conversion unit 33 via the optical monitoring control unit 31B and the monitoring control unit 34 in the wavelength multiplexing transmission device 3. It is recognized that a failure has occurred in path B.

  Further, the optical monitoring unit 331B of the optical wavelength conversion unit 33 corresponding to the wavelength corresponding to the optical wavelength conversion unit 43 in which the failure has occurred in the output unit also detects that the optical level of the optical wavelength signal having the wavelength has decreased. Therefore, the signal processing unit 333 also detects a failure by using the light level notified from the light monitoring unit 331B.

  After that, when the route A is disconnected as described above, each signal processing unit 333 detects that a failure has occurred in the route A, as in the example of FIG. In this case, since a failure has occurred in the route B, each signal processing unit 333 does not switch the route selected by the switching unit 332.

  If the optical wavelength demultiplexing units 32A and 32B output the WDM signal as it is, it may be difficult for the optical monitoring units 331A and 331B to detect a decrease in the optical level. For this reason, since the failure cannot be accurately detected only by the light monitoring units 331A and 331B, in this embodiment, not only the light monitoring units 331A and 331B but also the light monitoring control units 31A and 31B are used for detecting the failure. Yes.

  In the example of FIG. 5, it is assumed that the path B is disconnected between the wavelength division multiplexing transmission apparatuses 1 and 4, and then the path A is disconnected between the wavelength division multiplexing transmission apparatuses 1 and 2 as in the example of FIG. Yes.

  In this case, first, when the path B is disconnected between the wavelength division multiplexing transmission apparatuses 1 and 4, the optical wavelength conversion unit 43 in the wavelength division multiplexing transmission apparatus 4 detects a failure, and an optical monitoring signal indicating the failure is an optical signal. The monitoring control unit 47 transmits the signal to the optical monitoring control unit 31B in the downstream wavelength division multiplex transmission apparatus 3, and the failure is notified to each signal processing unit 333 via the monitoring control unit 34, and the failure occurs in the path B. It is recognized.

  After that, when the route A is disconnected as described above, each signal processing unit 333 detects that a failure has occurred in the route A, as in the example of FIG. In this case, since a failure has occurred in the route B, each signal processing unit 333 does not switch the route selected by the switching unit 332.

  As described above, according to this embodiment, the wavelength multiplexed signal transmitted through the selected path or the optical wavelength signal included in the wavelength multiplexed signal, and the wavelength multiplexed signal transmitted through each path or the wavelength multiplexed signal are transmitted. Since the failure is detected based on the optical wavelength signal included in the signal, it is not necessary to provide a signal processing unit for analyzing the wavelength multiplexed signal or the optical wavelength signal for each path, thereby increasing the scale and cost of the communication device. It becomes possible to suppress. It is also possible to detect a frame error, a bit error, etc. of the wavelength multiplexed signal transmitted through the operational transmission line.

  Further, in this embodiment, since the optical monitoring signal indicating the failure is combined with the WDM signal and notified from the upstream to the downstream, the configuration in which the WDM signal is output to the optical wavelength conversion unit as it is is based on the optical monitoring signal. It becomes possible to detect the failure.

  In the present embodiment, when the wavelength converters 2 and 4 for relay detect a failure that has occurred on the operational path, an alarm signal indicating the failure is output as a wavelength optical signal. Since the wavelength optical signal does not need to be blocked, it is possible to suppress the optical level of the WDM signal from changing suddenly and affecting the WDM signal transmitted through another path.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

  For example, although there are only two paths for transmitting a WDM signal, there may actually be a plurality of paths. When there are three or more routes, one route becomes an active route, and the other route becomes a standby route.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2013-147536 for which it applied on July 16, 2013, and takes in those the indications of all here.

1 to 4 Wavelength multiplexing transmission apparatus 11, 23, 33, 43 Optical wavelength conversion unit 12A, 12B, 24, 44 Optical wavelength multiplexing unit 13A, 13B, 21, 41 Wavelength monitoring unit 14, 26, 34, 46 Monitoring control unit 15A , 15B, 25, 45, 47, 31A, 31B Optical monitoring control unit 22, 42, 32A, 32B Optical wavelength separation unit 111, 333 Signal processing unit 112 Coupler unit 331A, 331B Optical monitoring unit 332 Switching unit

Claims (9)

A plurality of wavelengths are provided corresponding to each of a plurality of paths for transmitting a wavelength multiplexed signal in which a plurality of optical wavelength signals having different wavelengths are combined, and included in the wavelength multiplexed signal or the wavelength multiplexed signal transmitted through the corresponding path. An optical monitoring unit for detecting the optical level of the optical wavelength signal to be transmitted;
A switching unit that selects any one of the plurality of paths, and outputs a wavelength multiplexed signal transmitted through the selected path or an optical wavelength signal included in the wavelength multiplexed signal as an optical signal;
Based on the light level detected by the light monitoring unit and the optical signal output from the switching unit, a failure occurring in each path is detected, and the switching unit is selected according to the detection result. And a signal processing unit for switching a route to be transmitted.   2. The signal processing unit according to claim 1, wherein the signal processing unit analyzes the optical signal and detects a failure in a path selected by the switching unit when the optical signal includes at least one of a bit error and a frame error. Transmission equipment. The wavelength multiplexed signal is combined with an optical monitoring signal indicating each of the wavelengths of the plurality of optical wavelength signals included in the wavelength multiplexed signal,
A plurality of acquisition units that are provided corresponding to each of the plurality of paths, and that acquire the optical monitoring signal from the wavelength multiplexed signal that has transmitted the corresponding path;
The transmission apparatus according to claim 1, wherein the signal processing unit detects the failure based further on an optical monitoring signal acquired by the acquisition unit.   The transmission apparatus according to claim 3, wherein when the wavelength indicated by the optical monitoring signal no longer exists, the signal processing unit detects a failure in a path through which the wavelength multiplexed signal including the optical monitoring signal is transmitted. The wavelength multiplexed signal transmitted through the path selected by the switching unit includes a signal indicating a failure occurring in the path as the optical wavelength signal.
The wavelength division multiplexed signal transmitted through a route other than the route selected by the switching unit is combined with the optical monitoring signal further indicating a failure that has occurred in the route. Transmission equipment. A plurality of wavelengths are provided corresponding to each of a plurality of paths for transmitting a wavelength multiplexed signal in which a plurality of optical wavelength signals having different wavelengths are combined, and included in the wavelength multiplexed signal or the wavelength multiplexed signal transmitted through the corresponding path. An optical monitoring unit for detecting the optical level of the optical wavelength signal to be transmitted;
A switching unit that selects any one of the plurality of paths, and outputs a wavelength multiplexed signal transmitted through the selected path or an optical wavelength signal included in the wavelength multiplexed signal as an optical signal;
Based on the monitoring result of the light level by the light monitoring unit and the optical signal output from the switching unit, a failure occurring in each path is detected, and the switching unit is selected according to the detection result. A transmission device having a signal processing unit for switching a route to be transmitted;
And a plurality of relay transmission devices belonging to each of the plurality of paths. Each relay transmission device
A wavelength monitoring unit that detects each of the wavelengths of a plurality of optical wavelength signals included in the wavelength multiplexed signal;
An optical monitoring control unit that multiplexes and outputs an optical monitoring signal indicating each of the wavelengths detected by the wavelength monitoring unit to the wavelength multiplexed signal;
The transmission device is
A plurality of acquisition units that are provided corresponding to each of the plurality of paths, and that acquire the optical monitoring signal from the wavelength multiplexed signal that has transmitted the corresponding path;
The transmission system according to claim 6, wherein the signal processing unit detects the failure based further on an optical monitoring signal acquired by the acquisition unit. Each relay transmission device
A demultiplexer that demultiplexes the wavelength-multiplexed signal into optical wavelength signals included in the wavelength-multiplexed signal and outputs the demultiplexed signals;
Regeneration relay processing is performed on each optical wavelength signal output from the demultiplexing unit, and detection processing is performed to detect a failure that occurs in the path to which the relay transmission device belongs based on each optical wavelength signal, and the regeneration A regenerative repeater that outputs the optical wavelength signal subjected to the relay process;
A multiplexing unit that multiplexes and outputs the optical wavelength signals that have undergone the regenerative repeater processing in each regenerative repeater unit, and
When the regeneration relay unit of the relay transmission device belonging to the route selected by the switching unit detects the failure, it outputs an alarm signal indicating the failure as the optical wavelength signal,
When the regenerative repeater of the relay transmission device belonging to a path other than the path selected by the switching unit detects the failure, the optical supervisory control unit transmits an optical monitoring signal further indicating the failure to the wavelength multiplexed signal. The transmission system according to claim 7, wherein the transmission system is combined and output. Detecting the optical level of the wavelength multiplexed signal in which a plurality of optical wavelength signals having different wavelengths transmitted through each of the plurality of paths are combined or the optical wavelength signal included in the wavelength multiplexed signal,
Select one of the plurality of paths, and output the wavelength multiplexed signal transmitted through the selected path or the optical wavelength signal included in the wavelength multiplexed signal as an optical signal,
A path switching method that detects a failure that has occurred in each path based on the detected light level and the output optical signal, and switches the selected path according to the detection result.

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