JP5011257B2 - Path trace method and node device - Google Patents

Description

  The present invention relates to a path tracing method and a node device, and in particular, which optical signal among transmitted optical signals in a node on a transparent network including a transmission node, a relay node, and a reception node that does not include optical-electrical processing. The present invention relates to a path trace method and a node device for monitoring whether or not a message has arrived.

  Conventionally, in a transparent network as shown in FIG. 6, when transferring data from a certain transmission node to a certain reception node, the transmission node converts an electrical signal including the transfer data into an optical signal and transmits it to the reception node. The optical signal is converted into an electrical signal at. At this time, an optical path is set from the transmission node to the reception node, and an optical signal including transfer data is transferred. Here, the relay node that relays the optical path does not go through OEO (Optical Electrical Optical) processing, that is, from the transmitting node that terminates the optical path to the receiving node, it remains as an optical signal without being converted into an electrical signal. Transferred.

In addition to transfer data, transfer data information and transparent network control management information are added to the information transferred through the optical path, and are standardized by ITU-T (for example, Non-Patent Document 1, Non-Patent Document 1). Reference 2). In this, management information (path trace) indicating an optical path ID is also defined. In addition, it is stipulated in the relay node to determine whether or not an optical signal has arrived depending on whether or not the optical power is at a predetermined level.
ITU-T Recommendations G.707 / Y.1322 (12/2003), Network node interface for the synchronous digital hierarchy (SDH), section 9.3.1.1, etc ITU-T Recommendations G.709 (2003), Interfaces for the optical transport network (OTM)

  However, in the above conventional method, since the relay is performed without going through the OEO, the monitoring function in the relay node is limited to the optical power level. Therefore, in a transparent network, even if a different optical signal arrives due to a switch abnormality or the like in failure analysis when optical path setting fails, it cannot be distinguished from the original optical signal when monitored at the optical power level. If the wrong signal is higher than a predetermined level, it is judged as “normal” and cannot be judged as abnormal.

  The present invention has been made in view of the above points, and it is an object of the present invention to provide a path tracing method and system capable of accurately monitoring which optical signal reaches a relay node in a transparent network. .

The present invention (Claim 1) is information including path trace information for specifying an optical path, which includes a transmission node, a relay node, and a reception node, and is transferred through an optical path connecting the transmission node, the relay node, and the reception node. In a transparent network that does not include optical-electrical processing of information
Transmitting node, relay node, the receiving node both branches the wavelength-multiplexed signal input from another node wavelength-multiplexed signal A including the respective wavelength components, the wavelength-multiplexed signal B including the respective wavelength components, wavelength-multiplexed signal B A drop signal light is selected and output from the optical signal, and is composed of an optical add / drop multiplexer that outputs a signal light obtained by multiplexing the signal light selected from the wavelength multiplexed signal A and the add signal light,
A transparent network that connects the input and output of the sending node, relay node, and receiving node,
At the sending node:
As information identifying the optical path from the transmission transponder of the transmission node, information on the transmission / reception node, information on the external device connected to the transparent network in the transmission / reception node, or a connection location with the external device in the transmission / reception node Insert the path trace information including the information of the port to be identified into the overhead of the optical signal, and send it to the relay node via the add wavelength selective switch.
In the wavelength selection switch for the relay node node drop, select a predetermined optical signal,
In the monitoring transponder of the relay node, the overhead of the optical signal is acquired, and the path trace information inserted in the overhead is monitored to determine which optical signal is passing.

  FIG. 1 is a principle configuration diagram of the present invention.

The present invention (Claim 2 ) is information including path trace information for specifying an optical path in which a plurality of nodes are connected by an optical fiber, and is transferred through an optical path connecting a transmission node, a relay node, and a reception node. In transparent networks that do not involve opto-electrical processing of information,
Branching means 3 for branching a wavelength multiplexed signal input from another node device into a wavelength multiplexed signal A including each wavelength component and a wavelength multiplexed signal B including each wavelength component ;
An add wavelength selective switch 2 that selects a predetermined optical signal A from one of the wavelength multiplexed signals A branched by the branching means 3 in units of wavelengths, and transmits the selected optical signal A to a subsequent node;
Transmission / reception node information, information on external devices connected to the transparent network in the transmission / reception nodes, or path trace information including information on ports that identify connection points with external devices in the transmission / reception nodes are used as optical signal overhead. A transmission transponder 1 that is inserted and transmitted to another node device via the add wavelength selective switch 2;
A drop wavelength selective switch 4 for selecting a predetermined optical signal B in wavelength units from the other wavelength multiplexed signal B branched by the branching means 3;
A monitor transponder 5 which acquires the overhead of the optical signal output from the drop wavelength selective switch 4 and monitors which path trace information is inserted into the overhead to determine which optical signal is passing; Have

Further, the present invention (Claim 3 ) is provided for each input path (1 to N) of an optical signal.
Branching means for branching the wavelength multiplexed signal from the input path;
A drop wavelength selective switch for selecting a predetermined optical signal B in wavelength units from one of the wavelength multiplexed signals B branched by the branching means;
A path switching wavelength selection switch that switches the path of the other wavelength multiplexed signal A branched by the branching means and outputs the path to the add wavelength selection switch for each path;
Wavelength selection switch for add, which is provided in the same number as the path switching wavelength selection switch, selects a predetermined optical signal A from the wavelength multiplexed signal A input from the path switching wavelength selection switch in units of wavelength, and transmits it to the subsequent node When,
Have
Selecting means for selecting either one of the optical signal B on the basis of the wavelength of a plurality of optical signal B input from the N wavelength selective switch no-drop,
A monitor transponder that determines whether an optical signal corresponding to the path trace information passes through the optical signal input from the selection unit.

Further, the present invention (Claim 4 ) is provided for a redundant optical path.
For one optical path, it has a current transmission / reception transponder and a spare transmission / reception transponder,
The standby transmission / reception transponder is caused to function as a monitor transponder for other optical paths while waiting for the occurrence of a failure.

The present invention (Claim 5 ) is information including path trace information for specifying an optical path in which a plurality of nodes are connected by an optical fiber, and is transferred through an optical path connecting a transmission node, a relay node, and a reception node. In transparent networks that do not involve opto-electrical processing of information,
First branching means for branching the optical signal from the input path (1 to N) of the optical signal;
Second branching means for branching the optical signal input from the add port;
A wavelength selecting switch for adding the same number of input paths as the number of input paths for selecting an optical signal for each wavelength unit of the optical signal output from the first branching means and the second branching means,
A wavelength selective switch for selecting a wavelength from an optical signal input from the first branching means;
A wavelength selection switch for drop that selects an optical signal input from the wavelength selection switch in units of wavelengths;
Obtains the overhead of the optical signal output from the wavelength selective switch for dropping, is inserted into the overhead information transmitting and receiving nodes, the information of the external device connected to the transparent network in said transmission receiving node or, the A monitor transponder that monitors path trace information including information of a port that identifies a connection location with an external device in a transmission / reception node and determines which optical signal is passing through.

  According to the present invention, in a transparent network, the path trace information (maintenance signal) is inserted into the overhead of the main signal, and the optical signal is relayed by monitoring the main signal at the transponder by the drop & continue function of the relay node. It is possible to determine whether a node has been passed, and a highly reliable network can be constructed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
The transparent network is the same as in FIG.

  FIG. 2 shows a configuration of each node in the first exemplary embodiment of the present invention.

  The figure shows an example of a transmission node 100, a relay node 200, and a reception node 300 in a transparent network. The transmission node 100 includes an optical coupler 110 that branches an optical fiber signal, a drop WSS (Wavelength Selective Switch) 120 that switches an optical signal in units of wavelengths, an add WSS 130, and a transmission transponder (TPD) 140. In the figure, for the sake of explanation, only the transmission transponder related to the optical path to be monitored is shown, but the reception transponder for other optical paths or the monitor is connected to each port of the output of the drop WSS 120. A transmission transponder for another optical path may be connected to each port of the input transponder (a port to which nothing is connected in the figure).

  Similarly, the relay node 200 also includes an optical coupler 210, a drop WSS 220, an add WSS 230, and a monitor transponder (TPD) 240. Similar to the transmission node 100, an optical path receiving transponder, another optical path transponder, and a monitoring transponder may be connected.

  The reception node 300 also includes an optical coupler 310, a drop WSS 320, an add WSS 330, and a reception transponder (TPD) 340. In the receiving node 300, similarly to the above, an optical path receiving transponder, another optical path transponder, and a monitoring transponder may be connected.

  For the sake of explanation, FIG. 2 shows the configurations of the transmission node 100, the relay node 200, and the reception node 300, but they may all be the same configuration.

  The add WSSs 130, 230, and 330 have a plurality of input ports for inputting wavelength multiplexed signals and one output port for outputting wavelength multiplexed signals, and signals (optical paths) from which input ports for each wavelength. Is a switch that can select whether to connect to the output port.

  The drop WSSs 120, 220, and 320 have one input port for inputting a wavelength multiplexed signal and a plurality of output ports for outputting the wavelength multiplexed signal, and a signal (optical path) input from the input port for each wavelength. ) Is a switch that can select which output port to connect.

  When setting an optical path, at each node that terminates and relays the optical path, which input port and which wavelength corresponds to which WSS 130, 230, 330 for addition from a management control device (not shown) The switch is set in each WSS by specifying whether to connect (switch) the output port.

  The thick line shown in the figure indicates the flow of the main signal. The main signal is transmitted from the transmission TPD 140 of the transmission node 100 to the reception node 300 via the relay node 200.

  The transmission node 100 inserts the path trace information from the transmission TPD 140 into the overhead of the main signal and outputs it to the Add WSS 130. In the path trace information, information that can identify a path, for example, information on a transmission node / reception node, information on an external device connected to a transparent network in a transmission / reception node, or a connection location with an external device in a transmission / reception node Information such as ports is set. The Add WSS 130 outputs the main signal with the path trace information inserted to the relay node 200.

  In the relay node 200, when a main signal is input to the optical coupler 210, the optical coupler 210 branches the signal, one is input to the Drop WSS 220, and the other is input to the Add WSS 230. When the main signal is input to the drop WSS 220, an arbitrary wavelength is selected under the control of a management control function unit (not shown) and input to the monitor TPD 240. The monitor TPD 240 monitors the optical signal output from the port. In a situation where an optical path of a certain wavelength is to be relayed in a certain node, when monitoring whether the corresponding optical path is normally relayed to that wavelength of that node, in the drop WSS 220 of that node, Control is performed from a management control function unit (not shown) so that the corresponding wavelength is output to the output port to which the monitor transponder 240 is connected.

  The corresponding wavelength is transmitted to the drop transponder 240 by the drop WSS 220 and converted to an electric signal by the monitor transponder 240 to extract path trace information.

  If the extracted path trace information matches the path trace information of the corresponding optical path, it is determined as normal, and if it does not match, it is determined as abnormal.

  Note that the reception node 300 can monitor the path trace information of the main signal as in the relay node 200.

  In the present embodiment, by switching the wavelength connected to the monitor transponder 240 in the Drop WSS 220, it becomes possible to detect the path traces of the optical paths of all wavelengths by one monitor transponder 240.

  Since the reception transponder 330 originally has a function of extracting path trace information, the reception transponder 330 may be used as a monitor transponder. This means that, in order to realize the path trace detection function in the relay node 200 of the present invention, the same monitor function as the conventional one can be used while suppressing an increase in cost.

  In addition, when setting an optical path, there is a case where an optical path redundancy function is provided so that data transfer is not interrupted even if a failure occurs. In this case, two transmission / reception transponders are provided for one optical path, one for current use and the other for backup.

  When there is a redundant optical path in this way, the end node of the optical path is in a state of waiting without using the reception transponder prepared for backup until a failure occurs. By using the spare receiving transponder waiting for the occurrence of such a failure as a monitoring transponder for another optical path while waiting for the occurrence of the failure, any optical path can be provided without newly installing a monitoring transponder. Path trace can be detected. The control for receiving the optical path that should originally be repaired at the time of the failure and receiving the optical path to be monitored before the failure occurs is performed from the management control function unit (not shown) to the drop WSS. The switching control is specified so that the desired wavelength is transmitted to the receiving transponder so that the desired optical path can be received by the receiving transponder.

[Second Embodiment]
Next, a case will be described in which the first embodiment is applied to a multidegree configuration (WXC (Wavelength Cross Connect) or inter-ring connection). Here, the multi-degree refers to the number of input (output) power paths (number of input (output) power ports of wavelength multiplexed signals) in one node as the degree number. A degree 3 or higher is called a multi-degree.

  In the case of the ROADM system, it corresponds to degree 2, and inter-ring connection and WXC corresponds to degree 3 or higher.

  FIG. 3 shows the configuration of the relay node in the second exemplary embodiment of the present invention. In the figure, although a transmitting node and a receiving node are not shown, it is assumed that they have the same configuration as that of the relay node.

  The relay node 400 shown in the figure includes optical couplers 410, 411, 412 to which an optical signal is input for each route from an upper node, route switching WSSs 420, 421, 422, WSSs for addition 430, 431, 432, Drop WSSs 440, 441, and 442, a selector 450, and a monitor TPD 460. Although not shown in the figure, it is assumed that each node has a management control function unit for controlling the wavelength selection of the drop WSS, the selection of the selector route, the monitoring TPD, and the like. In the configuration of FIG. 3, an optical coupler may be used instead of the route switching WSS 420, 421, 422.

  As in the first embodiment, when an optical signal in which path trace information is inserted into the overhead of the main signal is input from the route 1 to the relay node 400, the optical coupler 410 transmits the optical signal. Branch and output to the route switching WSS 420 and the drop WSS 440. The route switching WSS 420 switches the optical signal input from the optical coupler 410 in units of wavelengths, and outputs the optical signal to the add WSSs 430, 431, and 432. The drop WSS 440 drops the main signal including the path trace information input from the optical coupler 410 and outputs the dropped main signal to the drop WSS 441.

  Similarly, when an optical signal into which the main signal overhead path trace information is inserted is input from the path 2, the optical coupler 411 branches the optical signal and outputs it to the path switching WSS 421 and the Drop WSS 441. . The path switching WSS 421 switches the optical signal input from the optical coupler 411 in units of wavelength and outputs the optical signal to the add WSSs 430, 431, and 432. The drop WSS 441 drops the main signal including the path trace information input from the optical coupler 411 and outputs the dropped main signal to the drop WSS 442.

  The selector 450 outputs the optical signal from the port designated based on the path trace information input from the drop WSS 442 to the monitor TPD 460.

  Similar to the first embodiment, the monitor TPD 460 determines whether an optical signal is output from the port number specified by the path trace information.

[Third Embodiment]
FIG. 4 shows the configuration of the relay node in the third exemplary embodiment of the present invention.

  The relay node shown in FIG. 1 includes optical couplers 501, 502, 503, and 504, Add WSSs 430, 431, 432, WSS 433, Drop WSS 542, and monitor transponder 560.

  The optical couplers 501, 502, and 503 are used in common with the drop optical couplers 410, 411, and 412 in FIG. 3 by changing the path switching WSSs 420, 421, and 422 in FIG. 3 to optical couplers. The Add port is connected to the WSSs 430, 431, and 432 for Add in each route via the optical coupler 504.

  The WSS 433 selects a wavelength from the optical signals branched from the optical couplers 501, 502, and 503 and outputs the selected wavelength to the drop WSS 542. The wavelength selected by the drop WSS 542 is output to the drop port and the monitor transponder 560. Similarly to the above, the monitor transponder 560 determines whether an optical signal is output from the port number specified by the path trace information.

  With the above configuration, the wavelength multiplexed signal input from each route (route 1 to route 3) and the optical signal input from the Add port of the optical coupler 504 are distributed to each route by each optical coupler. To do. As a result, the transmission node 100 and the relay node 200 can output (broadcast) the optical signal in two directions.

  Further, when switching the optical path to another route, the same signal is distributed to the switching destination route, and the path trace is performed at the relay node of the switching destination route and the monitoring transponder of the receiving node 300 of the switching destination route. Monitor information and BER (bit error rate).

  This makes it possible to check the normality of the switching destination path when switching the optical path to another path when a path failure occurs or during maintenance such as trouble relocation.

  In addition, when a failure occurs, after switching the optical path to another path, the normality of the original path can be confirmed. Specifically, there is a network as shown in FIG. 5, and when setting a route from A to C, the working path is A-B-C, and the restoration path is A-D-E-F- When C is set, the path is switched to the A-D-E-F-C restoration path when a failure occurs in the path ABC. For this reason, in addition to the WSS in the direction of restoration, the WSS in the direction of the original route is also set, and the same signal as the signal of the restoration path can be transmitted to the original route ABC. it can. Further, in the relay node B and the receiving node C on the original route, the normality to the node can be confirmed by receiving the signal branched by the optical coupler by the monitoring transponder.

  Further, the normality confirmation of the route can be monitored in-service and at a digital level.

  The present invention is not limited to the above-described embodiment, and various modifications and applications can be made within the scope of the claims.

  The present invention can be applied to a technique for performing path tracing in a transparent network.

It is a principle block diagram of this invention. It is a block diagram of each node in the 1st Embodiment of this invention. It is a block diagram of the relay node in the 2nd Embodiment of this invention. It is a block diagram of the relay node in the 3rd Embodiment of this invention. It is a figure which shows the normality confirmation operation | movement of the original path | route in the 3rd Embodiment of this invention. It is an example of a transparent network.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmission transponder 2 Add wavelength selection switch 3 Branch means 4 Drop wavelength selection switch 5 Monitor transponder 10 Node device 100 Transmission node 110 branch means, Optical coupler 120 Drop wavelength selection switch 130 Add wavelength selection switch 140 For transmission Transponder 200 Relay node 210 Branch means, optical coupler 220 drop wavelength selection switch 230 add wavelength selection switch 240 monitor transponder 300 reception node 310 optical coupler 320 drop wavelength selection switch 330 reception transponder 340 add wavelength selection switch 400 relay Nodes 410, 411, 412 Optical couplers 420, 421, 422 Path switching wavelength selective switches 430, 431, 432 Add wavelength selective switches 440, 441, 442 Transponder drop wavelength selection switch 450 selector 460 monitors 501, 502, 503, 504 optical coupler 433 wavelength selective switch 542 for dropping wavelength selective switches 560 for monitoring transponder

Claims (5)

Information consisting of a transmission node, a relay node, and a reception node and including path trace information for specifying an optical path, including optical-electrical processing of information transferred on an optical path connecting the transmission node, the relay node, and the reception node Not in a transparent network,
Both the transmitting node, the relay node, and the receiving node branch a wavelength multiplexed signal input from another node into a wavelength multiplexed signal A including each wavelength component and a wavelength multiplexed signal B including each wavelength component, A drop signal light is selected from the wavelength multiplexed signal B and output, and is constituted by an optical add / drop multiplexer for outputting a signal light obtained by multiplexing the signal light selected from the wavelength multiplexed signal A and the add signal light,
A transparent network connecting input and output of the transmitting node, the relay node, and the receiving node,
In the sending node,
As information identifying the optical path from the transmission transponder of the transmission node, information on the transmission / reception node, information on an external device connected to the transparent network in the transmission / reception node, or connection with an external device at the transmission / reception node Inserting the path trace information including the information of the port specifying the location into the overhead of the optical signal, and transmitting it to the relay node via the add wavelength selective switch,
In the wavelength selective switch for the relay node node drop, a predetermined optical signal is selected,
The monitoring transponder of the relay node acquires the optical signal overhead and monitors the path trace information inserted in the overhead to determine which optical signal is passing. Path trace method. Information including path trace information for specifying an optical path in which a plurality of nodes are connected by an optical fiber, and does not include optical-electrical processing of information transferred through an optical path connecting a transmission node, a relay node, and a reception node. In a transparent network,
Branching means for branching a wavelength multiplexed signal input from another node device into a wavelength multiplexed signal A including each wavelength component and a wavelength multiplexed signal B including each wavelength component ;
A wavelength selecting switch for add that selects a predetermined optical signal A from one of the wavelength multiplexed signals A branched by the branching unit in units of wavelength, and transmits the selected signal to a subsequent node;
The path trace information including information on a transmission / reception node, information on an external device connected to a transparent network in the transmission / reception node, or information on a port specifying a connection location with the external device in the transmission / reception node is used as an optical signal overhead. A transmission transponder that transmits to another node device via the add wavelength selective switch;
A wavelength selecting switch for dropping that selects a predetermined optical signal B in wavelength units from the other wavelength multiplexed signal B branched by the branching means;
A monitor transponder that obtains the overhead of the optical signal output from the drop wavelength selective switch and monitors the path trace information inserted in the overhead to determine which optical signal is passing;
A node device comprising: For each input path (1 to N) of the optical signal,
The branching means for branching the wavelength multiplexed signal from the input path;
A drop wavelength selective switch for selecting a predetermined optical signal B in wavelength units from one wavelength multiplexed signal B branched by the branching means;
A path switching wavelength selection switch that switches the path of the other wavelength multiplexed signal A branched by the branching means and outputs the path to the add wavelength selection switch for each path;
Wavelength for adding, provided in the same number as the path switching wavelength selection switch, for selecting a predetermined optical signal A from the wavelength multiplexed signal A input from the path switching wavelength selection switch in units of wavelength and transmitting it to a subsequent node A selection switch;
Have
Selecting means for selecting either one of the optical signal B on the basis of the wavelength from the N plurality of the optical signal B input from the wavelength selective switch for dropping,
A monitor transponder that determines whether the optical signal corresponding to the path trace information passes through the optical signal input from the selection unit;
The node device according to claim 2 . For redundant optical paths,
For one optical path, it has a current transmission / reception transponder and a spare transmission / reception transponder,
4. The node device according to claim 3, wherein the standby transmission / reception transponder is caused to function as a monitoring transponder for another optical path while waiting for occurrence of a failure. Information including path trace information for specifying an optical path in which a plurality of nodes are connected by an optical fiber, and does not include optical-electrical processing of information transferred through an optical path connecting a transmission node, a relay node, and a reception node. In a transparent network,
First branching means for branching the optical signal from the input path (1 to N) of the optical signal;
Second branching means for branching the optical signal input from the add port;
It said first branching means, and said selecting the optical signal into each wavelength of the second optical signal outputted from the branching means and the input side the same number of add-wavelength selective switch and path to be transmitted to the subsequent node ,
A wavelength selective switch for selecting a wavelength from the optical signal input from the first branching unit;
A wavelength selection switch for dropping that selects an optical signal input from the wavelength selective switch in units of wavelengths;
Obtains the overhead of the optical signal output from the wavelength selective switch for dropping, is inserted into the overhead information transmitting and receiving nodes, the information of the external device connected to the transparent network in said transmission receiving node or, A monitor transponder that monitors the path trace information including information of a port that identifies a connection point with an external device in the transmission / reception node and determines which optical signal is passing;
A node device comprising:

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