WO2012117564A1

WO2012117564A1 - A wavelength path control system, a wavelength path controlling method, and a storage medium for storing a wavelength path controlling program

Info

Publication number: WO2012117564A1
Application number: PCT/JP2011/055158
Authority: WO
Inventors: Shaowei HUANG; Itaru Nishioka; Akio Tajima
Original assignee: Nec Corporation
Priority date: 2011-02-28
Filing date: 2011-02-28
Publication date: 2012-09-07
Also published as: JP5796634B2; JP2014508429A

Abstract

[Technical Problem] With an increase of network traffic, it is desirable to increase the wavelength path availability instead of placing more wavelengths into a fiber. [Solution to Problem] A wavelength path control system according to an exemplary aspect of the invention includes: a path computation means for computing which existing wavelength path is needed to be monitored when receiving a request for setting a new wavelength path or a request for configuring a wavelength path from a node; a monitoring means for monitoring signal quality of the existing wavelength path needed to be monitored and the new wavelength path; and a wavelength path control means for controlling to continue or stop setting the new wavelength path or configuring the wavelength path, based on the signal quality monitored by the monitoring management means.

Description

DESCRIPTION

Title of Invention

A wavelength path control system, a wavelength path controlling method, and a storage medium for storing a wavelength path controlling program

Technical Field

The present invention relates generally to a wavelength path control system, a wavelength path controlling method, and a storage medium for storing a wavelength path controlling program, which are used for Wavelength Division Multiplexing (WDM) network.

Background Art

WDM technology enables optical signals carried by different wavelengths to be multiplexed on a single fiber, in which each wavelength is treated as an individual path. To deal with network upgrade due to future revenue growth of Internet traffic or service recovery upon network failures, dynamic wavelength path control is needed to set up or tear down wavelength path or reroute the wavelength path suffering failures. Network elements (NE) with reconfiguration capability, such as wavelength cross-connects (WXC) or re-configurable optical add/drop multiplexers (ROADM), etc., can be deployed to realize dynamically switching a wavelength path from one output port to another.

However, in WDM networks signal quality of the wavelength path is degraded by linear and non-linear optical impairments. For example, to wavelength paths traversing the same fiber, they interfere with each other by non-linear effects such as four-wave mixing (FWM) and cross-phase modulation (XPM); to wavelength paths being switched at an optical node, they interfere with each other by linear effects such as intra-/inter-channel cross-talks occurring at optical switches, wavelength de-multiplexer and multiplexer.

Generally, the degradation level relates to the number of multiplexed wavelength paths and their optical power level and phase. In other words, dynamically setting up/tearing down a wavelength path or changing optical features of a wavelength path has impact on the signal quality of other wavelength paths. Deployment of regenerators using optical-electrical-optical (OEO) conversion at every node can help to eliminate this impact, but results in network capital expenditure (CAPEX) increase and loss of the transparency of all-optical switching, e.g., signal format transparency, protocol transparency. In WDM networks without OEO regeneration capability, besides the signal quality of the dynamically configured wavelength path, it is also necessary to take into consideration the signal quality degradation of other existing wavelength paths that are influenced by the dynamic configuration.

One example of technique considering the signal qualities of both the dynamically configured wavelength path and the influenced wavelength paths is disclosed in Patent Literature 1 , in which two threshold values are defined to help making a decision to continue or stop the dynamic configuration. One of the threshold values represents the signal quality level desired by the dynamically configured wavelength path. Another threshold value represents the signal quality level not causing the influenced wavelength paths to suffer errors. An approximate optical signal to noise ratio (OSNR) computation model taking into account amplification spontaneous emission (ASE) noise is defined and used to calculate the OSNR hop by hop along the new wavelength path. At each hop, the calculated OSNR level is compared to the two threshold values. Only when the calculated OSNR is larger than the two threshold values, the new wavelength path is allowed to be established. By this technique, the existing wavelength paths can be protected from suffering errors due to the new wavelength path setup.

[Citation List]

[Patent Literature]

[Patent Literature 1] Japanese Patent Application Laid-Open No. 2010-062647 Summary of Invention

[Technical Problem]

However, as described above, signal quality of a wavelength path is also degraded by cross-talks, FWM and XPM, etc. Absence of taking such impairments into consideration leads to signal quality over-estimation. To avoid causing errors to the existing wavelength paths based on the over-estimated signal quality, the two threshold values are set large enough with considering the maximum degradation effect caused by cross-talks, FWM and XPM. High threshold values can guarantee to make an accurate decision, but the major disadvantage is to increase the rejections of dynamic wavelength path configuration request. This consequently limits the total number of wavelength paths that can be established in the network and decreases the wavelength resource utilization efficiency. With the drastic increase of Internet traffic, it would be desirable to increase the wavelength path availability instead of placing more wavelengths into a fiber.

The present invention is conceived in consideration of the above mentioned circumstances, and an object of the present invention is to provide a wavelength path control system, a wavelength path controlling method, and a storage medium for storing a wavelength path controlling program.

[Solution to Problem] ,

A wavelength path control system according to an exemplary aspect of the invention includes: a path computation means for computing which existing wavelength path is needed to be monitored when receiving a request for setting a new wavelength path or a request for configuring a wavelength path from a node; a monitoring means for monitoring signal quality of the existing wavelength path needed to be monitored and the new wavelength path; and a wavelength path control means for controlling to continue or stop setting the new wavelength path or configuring the wavelength path, based on the signal quality monitored by the monitoring management means.

A wavelength path control method according to an exemplary aspect of the invention includes: computing which existing wavelength path is needed to be monitored when receiving a request for setting a new wavelength path or a request for configuring a wavelength path from a node; monitoring signal quality of the existing wavelength path needed to be monitored and the new wavelength path; and controlling to continue or stop setting the new wavelength path or configuring the wavelength path, based on the signal quality monitored. A storage medium for storing a wavelength path control program according to an exemplary aspect of the invention includes: a computing process computing which existing wavelength path is needed to be monitored when receiving a request for setting a new wavelength path or a request for configuring a wavelength path from a node; a monitoring process monitoring signal quality of the existing wavelength path needed to be monitored and the new wavelength path; and a controlling process to continue or stop setting the new wavelength path or configuring the wavelength path, based on the signal quality monitored.

[Advantageous Effects of Invention]

According to the present invention, it is possible to control wavelength path without causing potential errors to wavelength paths in a network, even if the traffic in the network increases.

Brief Description of Drawings

[FIG. 1 ] is a block diagram showing a configuration of a network apparatus according to a first exemplary embodiment of the present invention.

[FIG. 2] is a flow chart showing an operation according to a first exemplary embodiment of the present invention.

[FIG. 3] is a block diagram showing a configuration of an optical network according to a second exemplary embodiment of the present invention.

[FIG. 4] is a block diagram showing a configuration of a node according to a second exemplary embodiment of the present invention.

[FIG. 5] is a block diagram showing a configuration of a transponder according to a second exemplary embodiment of the present invention.

[FIG. 6] is a block diagram showing a configuration of a monitoring management unit according to a second exemplary embodiment of the present invention.

[FIG. 7] is a block diagram showing a configuration of a nodal control unit according to a second exemplary embodiment of the present invention.

[FIG. 8] is a flow chart showing an operation according to a second exemplary embodiment of the present invention.

[FIG. 9] is a sequence diagram showing an operation according to a second exemplary embodiment of the present invention.

[FIG. 10] is a sequence diagram showing an operation according to a second exemplary embodiment of the present invention.

[FIG. 11] is a sequence diagram showing an operation according to a second exemplary embodiment of the present invention.

Description of Embodiments

Hereinafter, the exemplary embodiments of the present invention are described in detail with reference to accompanying drawings.

(First exemplary embodiment)

FIG. 1 shows a configuration of a wavelength path control system 1000 according to a first exemplary embodiment of the present invention.

According to FIG. 1 , the wavelength path controlling system 1000 includes a path computation unit 1001 , a monitoring unit 1002, and a wavelength path control unit 1003.

FIG. 2 shows an operation carried out by the wavelength path controlling system 1000. The operation carried out by the wavelength path controlling system 1000 and each of the elements in the wavelength path controlling system 1000 will be described in the following.

First, the path computation unit 1001 receives the request of setting a new wavelength path or configuring a wavelength path from a network element, which is not shown in FIG. 1. Then, the path computation unit 1001 computes which existing wavelength path is needed to be monitored in step S I 001.

After step S I 001 , the monitoring unit 1002 monitors signal quality of the existing wavelength path needed to be monitored and the new wavelength path which are computed in the step S I 001 (step S I 002).

Once the monitoring in step S I 002 started, the wavelength path control unit 1003 controls to continue or stop the new wavelength path setup or the wavelength path configuration (step S 1003). The control in step S I 003 is carried out based on the signal quality monitored in step S I 002. (Advantageous effect of the first exemplary embodiment)

According to the first exemplary embodiment described above, it is possible to control wavelength path without degradation in signal quality, even if the traffic in a network increases. This is because the monitoring unit 1002 monitors both of the new wavelength path and the existing path which is needed to be monitored computed by the path computation unit 1001.

(Second exemplary embodiment)

FIG. 3 shows a block diagram of a configuration of an optical network according to a second exemplary embodiment.

According to FIG. 3, an optical network includes nodes 100 to 105, a network management system (NMS) 300, a monitoring point computation unit 400, a wavelength path (WP) control unit 500, and a wavelength path database (WP DB) 600.

The NMS 300 manages the optical network. The monitoring point computation unit 400 computes monitoring point in wavelength paths. The WP control unit 500 controls wavelength paths. The details of the nodes 100 to 105 and the units above will be described later.

The nodes 101 to 105 are connected by bi-directional linked optical fibers, in which optical signals are transmitted in opposite directions. Optical signals transmitted in the same direction are carried by different wavelengths. Each of the nodes 100 to 105 is a type of network elements (NEs) which is capable of switching wavelength paths.

A wavelength path in the optical network is referred to a wavelength carrying optical signal transmitted at one of the nodes 100 to 105 and received at another node 101 to 105. A wavelength path may traverse more than one of the nodes 100 to 105 along the optical fibers, but it can only occupy one wavelength in every optical fiber. For example, as shown in FIG. 3, a wavelength path WP-A between the node 100 and the node 105 is configured. In general, it is a bi-directional wavelength path, but only one direction is drawn in FIG. 3 for simplicity. Along the path WP-A, the nodes 100, 101 , 102 and 105 are passed, and optical fibers between node pairs (100, 101 ), (101 , 102) and (102, 105) are traversed. A wavelength path WP-B is also shown in FIG. 3. Along the path WP-B, the nodes 104, 101 , and 102 are passed, and optical fibers between node pairs (104, 101), ( 101 , 102) are traversed.

The combination of the nodes 100 to 105 and optical fibers taking responsibility of optical signal transmission is referred to data plane. On the other hand, NMS 300, Monitoring point computation unit 400, WP control unit 500, and WP DB 600 taking responsibility of performing wavelength path control, management and status record. The combination of these units is referred to management and control plane.

A structure of the node 100 is shown in FIG. 4. According to FIG. 4, the node 100 includes optical amplifiers 1 10, a wavelength de-multiplexer/multiplexer

(DEMUX/MUX) and switching unit 120, transponders 130, a monitoring management unit 140, and a nodal control unit 150. The node 100 is connected to the other nodes via optical fibers 200. The other nodes 101 to 105 have the same structure to the node 100.

A wavelength path can be switched at the node 100 from one input optical fiber 200 to another output optical fiber 200, or added/dropped from/to the transponder 130.

As shown in FIG. 4, optical signals experiencing long distance transmission along optical fibers 200 are amplified first by the input optical amplifier 1 10 before the processing at the wavelength DEMUX/MUX and switching unit 120. After being processed by the wavelength DEMUX/MUX and switching unit 120, the optical signals are amplified by the output optical amplifier 1 10 for the next transmission. For the optical amplifiers 110, erbium-doped fiber amplifier (EDFA) can be used, for example.

At the wavelength DEMUX/MUX and switching unit 120 optical signals after the input optical amplifier 1 10 are first de-multiplexed into individual wavelengths. The optical signals of these de-multiplexed wavelengths can be forwarded to specified wavelength ports mapped to different output optical fibers 200 or transponders 130. The optical signals forwarded to optical fiber 200 are multiplexed again by the wavelength DEMUX/MUX and switching unit 120 before the optical signals are amplified by the output optical amplifier 110. The wavelength de-multiplexing and multiplexing process can be performed by passive wavelength device, e.g. array waveguide grating (AWG).

The nodal control unit 150 is deployed to control the optical amplifier 1 10 and the wavelength DEMUX/MUX and switching unit 120, which receives/sends the request/response from/to the management and control plane mentioned in FIG. 3. The monitoring management unit 140 is deployed to manage and record the signal quality values for different wavelength paths terminated at the node. If the monitoring management unit 140 detects the signal quality value lower than the preset threshold indicating a risk of experiencing errors, it generates an alarm to the nodal control unit 150 and the nodal control unit 150 sends an alarm notification to the WP control unit 500.

A structure of the transponder 130 is shown in FIG. 5. The transponder 130 is used to transmit and receive optical signal for a wavelength path. According to FIG. 5, the transponder 130 includes a WDM transmitter 131 , a WDM receiver 132, a signal quality monitoring unit 133, a local signal receiver 134, and a local signal transmitter 135.

WDM signals are received in the WDM receiver 132, and are transmitted in the WDM transmitter 131. Input client signals are received in the local signal receiver 134, and are transmitted by the local signal transmitter 135. The format of the client signal can be Giga-bit Ethernet (GbE), 10 GbE, STM (Synchronous Transport Module) -4/16/64 or OC (Optical Carrier) - 12/48/192, etc.

In signal quality monitoring unit 133 the signal quality can be evaluated by using optical signal-to-noise ratio (OSNR), bit error rate (BER) or the number of corrected bits by forward error correction (FEC), etc. In the second exemplary embodiment, the method of counting the bits corrected by FEC is deployed. The monitoring results will be sent to the monitoring management unit 140. To realize dynamic wavelength path configuration, e.g., transmitter output power adjustment, the WDM signal transmitter 131 and receiver 132 can be controlled by the nodal control unit 150. FIG. 6 shows a structure of the monitoring management unit 140. According to FIG. 6, the monitoring management unit 140 includes a signal quality database 141 and an alarm decision unit 142. The signal quality database 141 records the signal quality value obtained from the signal quality monitoring unit 133 and updates the records periodically. The alarm decision unit 142 decides whether the alarm decision unit 142 should generate an alarm to the nodal control unit 150 based upon the signal quality database 141.

The alarm decision unit 142 may use any algorithms to decide whether the alarm decision unit 142 should generate an alarm or not. The algorithm may be using a threshold value of signal quality or the time to receive signals. For example, a threshold value X is set in the alarm decision unit 142 and Y is set as the computed value based upon the database 141. If Y > X, the monitoring management unit 140 generates an alarm to the nodal control unit 150, which indicates that an error occurs during the dynamic wavelength path configuration procedures. The value Y can be computed by using the following formula, Y=Bc/Br. In the formula above, Br denotes the total data bits received by the transponder 130 and Be denotes the corrected bits by FEC during a given period. A higher Y value means a worse transmission condition which the wavelength path experiences.

FIG. 7 shows a structure of the nodal control unit 150. According to FIG. 7, the nodal control unit 150 includes a signal quality alarm control unit 151 and a wavelength management unit 152. The signal quality alarm control unit 151 sends a notify message to the WP control unit 500 when it receives an alarm from the monitoring management unit 140.

From the following description, how the dynamic wavelength path control operated is to be explained, by referring to FIG. 8, FIG. 9, FIG. 10, and FIG. 11. First, FIG. 8 shows the flowchart of how a dynamic wavelength path configuration request is processed.

In the following description, let the wavelength path WP-B be an existing path, and the wavelength path WP-A be a new wavelength path to be set.

In step S700, a dynamic wavelength path configuration request is generated at the sender node. The dynamic wavelength path configuration request ("the request") can be a request for new wavelength path establishment or transmission power adjustment. In the following description, the node 100 is set as the "sender node" and the request is for new wavelength path (WP-A) establishment.

The node 100 sends the request to the NMS 300 and receives a response from the NMS 300. The request includes the information of a wavelength path ID, and the source and destination node IDs.

Upon receiving the request from the node 100, the NMS 300 checks the request type based on the WP DB 600 in step S701. If the requested wavelength path ID is not included in the WP DB 600, it is regarded as a new wavelength path setup request. If it is a request for new wavelength path setup, the NMS 300 performs routing and wavelength assignment for this request first in step S702 and then forwards the route information to the monitoring point computation unit 400. Here, any algorithms can be used for routing and wavelength assignment. An example for routing algorithms is OSPF (Open Shortest Path First) algorithm. On the other hand, if the request is not for new wavelength path setup, then the step S702 is skipped.

In step S703, the computation of which existing wavelength paths are influenced by the requesting dynamic configuration is performed. If an existing wavelength path traverses an optical fiber which the wavelength path requesting dynamic

configuration does, it is regarded as an influenced wavelength path. The number of the influenced path can be more than one. In this computation, the monitoring point computation unit 400 retrieves the wavelength path information from the WP DB 600. In the case of FIG. 3, the existing path WP-B is an influenced path, since WP-B traverses the optical fiber (101 , 102), which is also traversed by the new path WP-A.

After the computation in step S703, the monitoring point computation unit 400 forwards the information including wavelength path ID, source and destination node IDs of each influenced wavelength path to the WP control unit 500.

In step S704, the WP control unit 500 sends requests to the receiver node of the influenced wavelength paths and the new wavelength path, requesting to start the monitoring process for the signal quality of the influenced wavelength paths and the new wavelength path. In the case of FIG. 3, the WP control unit 500 sends a request to the receiver node of WP-A and the receiver node of WP-B, which are the node 105 and the node 102, respectively.

If the WP control unit 500 confirms that the monitoring management unit 140 in the receiver node 105 and 102 gets ready for monitoring process in step S705, the sender node 100 starts the dynamic configuration process in step S706. In step S706, the sender node 100 sends training data bits instead of the real traffic from the application before it is informed to do that. The training data pattern can be arbitrary unless it is different from the real traffic.

During the training data transmission, if there is any alarm detected from the influenced wavelength paths or the new wavelength path in step S707, the WP control unit 500 stops the dynamic wavelength path configuration. At the same time, the WP control unit 500 sends a notice of failure to the sender node 100 that there is a risk of causing the existing wavelength path to suffer errors in step S708. Then the monitoring processes run for the influenced wavelength paths are stopped in step S709. Otherwise, if there is not any alarm during a certain amount of time, the monitoring management unit 140 checks whether it achieves a satisfying signal quality with the current configuration in step S710. For example, the certain amount of time may be the time until the wavelength path configuration ends. If a satisfying signal quality is achieved, the sender node 100 receives a notice of success of dynamic configuration in step S712 and the monitoring processes run for the influenced wavelength paths are stopped in step S713. Otherwise, if a satisfying signal quality is not achieved, the dynamic configuration is continued in step S711. Only when the sender node 100 receives a notice of success of dynamic configuration, the real traffic from the application can be sent along the wavelength path in step S714.

FIG. 9 shows a signaling sequence used to start the multi-point monitoring process upon a dynamic wavelength path configuration request. The sender node 100 sends a dynamic wavelength path configuration request message 800 to the NMS 300 in step S700. Then the NMS 300 sends a request message 801 to the monitoring point computation unit 400 after steps S701 and S702 shown in FIG. 8 are executed. In the case of new wavelength path setup, the request message 801 includes the ID and route information of the new wavelength path. In the case of dynamic optical parameter adjustment, e.g., transmitter output power adjustment, only the wavelength path ID is included in the request.

After the computation of influenced wavelength paths is done in step S703, the monitoring point computation unit 400 sends a message 802 to the WP control unit 500. The message 802 includes a list of influenced wavelength paths identified by wavelength path ID, source and destination node IDs.

For each influenced wavelength path listed, the WP control unit 500 sends massages 803 to the nodal control unit 150 of the source node and to the destination node of the influenced wavelength paths. The messages 803 are sent after step S704 is done. The messages 803 include the wavelength path ID information and the node ID information.

The nodal control unit 150 then sends a request message 804 to the monitoring management unit 140 requesting to start the signal quality monitoring process. Once the monitoring management unit 140 gets ready for the tracing process, it returns a response message 805 to the nodal control unit 150.

A message 806 is sent back to the WP control unit 500 by the nodal control unit 150. The message 806 includes the information indicating that the monitoring management unit 140 gets ready and an ID of the WP control unit 500, such as an IP (Internet Protocol) address.

When the WP control 500 receives the message 806 from all influenced wavelength paths, the WP control unit 500 directly informs NMS 300 by a message 807 that the sender node 100 can start the dynamic configuration procedures. The message 807 includes the information of an ID of NMS 300 such as an IP address, the wavelength path ID and state of indicating that all monitoring management units 140 get ready for monitoring the signal quality variation upon the dynamic wavelength path configuration.

The sender node 100 starts the dynamic configuration when the sender node 100 receives a message 808 from the NMS 300. The message 808 includes the information of the wavelength path ID, source and destination node IDs, and state of indicating that the sender node 100 is allowed to start the dynamic configuration procedures.

FIG. 10 shows a signal sequence when the dynamic wavelength path configuration causes the influenced wavelength paths to suffer potential errors. That is, the sequence shown in FIG. 10 corresponds to the steps S707 (yes) to S709 in FIG. 8. If the condition which is set in the monitoring management unit (Y>X, for example) is satisfied by the computation in the monitoring management unit 140, the monitoring unit 140 generates an alarm message 809 to the nodal control unit 150 to inform a risk of suffering errors. The nodal control unit 150 then notifies the WP control unit 500 that errors occur during the dynamic wavelength path configuration by a message 810. The message 810 includes an error code identifying the error type and an ID of the WP control unit 500, such as an IP address.

Since the WP control unit 500 receives an error message 810, the WP control unit 500 signals the nodal control units 150 in all influenced wavelength paths to terminate the signal quality variation tracing process by a message 811. The message 811 includes the wavelength path ID, source and destination node ID information for each influenced wavelength path. On receiving the message 811 , the nodal control unit 150 requests the monitoring management unit 140 to terminate the monitoring process by a message 812.

At the same time, the WP control unit 500 also sends a message 813 to the NMS 300 to inform an error during the dynamic configuration procedures. The message 813 includes the information of an ID of NMS 300 such as an IP address, the wavelength path ID and an error code indicating a failure due to cause the influenced wavelength paths to suffer errors.

Then the NMS 300 sends a message 814 informing to stop the dynamic

configuration process. The message 814 includes the information of the wavelength path ID, source and destination node IDs and an error code indicating a failure due to cause the influenced wavelength paths to suffer errors.

At last, FIG. 11 shows a signaling sequence when the dynamic wavelength path configuration is successful. That is, the sequence shown in FIG. 11 corresponds to the steps S710 (yes) to S714. After the steps S710 to S713 are executed, the WP control unit 500 sends a message 815 to the nodal control unit 150 to terminate the signal quality monitoring process. The WP control unit 500 also sends a message 816 to the NMS 300 to inform a success in dynamic configuration.

The NMS 300 sends a message 817 notifying a completion of dynamic

configuration preparation. Then the sender node 100 starts to send the real traffic from the application.

(Advantageous effect of the second exemplary embodiment)

According to the second exemplary embodiment described above, it is possible to control wavelength path without degradation in signal quality, even if the traffic in the optical network increases. It also causes an increase in the wavelength resource utilization efficiency. This is because both of the signal quality of the new wavelength path and the existing path are monitored.

Moreover, according to the second exemplary embodiment, it is possible to deal with not only a new wavelength path setup, but also a dynamic path configuration. This is because both of the signal quality of the new wavelength path and the existing path are monitored.

While the invention has been particularly shown and described with reference to exemplary embodiments thereof, the invention is not limited to these embodiments. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the claims.

For example, the operation in each exemplary embodiment mentioned above (operation shown in the flowchart and each sequence chart) can be carried out by hardware, software or a combined configuration of the software and the hardware.

In the case of carrying out a process by software, it may be possible that a program, which records sequence of the processes, is installed in a memory of a computer mounted on dedicated hardware and then, is executed. It may be also possible that the program is installed and executed in a general-purpose computer which can carry out various processes. For example, it is possible that the program is recorded in advance in a hard disk and ROM (Read Only Memory) as a storage medium. It is also possible that the program is stored (recorded) temporarily or permanently in a removable storage medium such as CD-ROM (Compact Disc Read Only Memory), a MO (Magneto optical) disk, DVD (Digital Versatile Disc), a magnetic disk, a semiconductor memory or the like. It is possible to provide such removable storage medium as so-called packaged software.

Further, it may be possible that the program is installed through being read from the removable storage medium as mentioned above and it may be also possible that the program is transferred by radio from a download site to the computer as other method. It may be also possible that the program is transferred by a wire to the computer via a network such as LAN (Local Area Network) and the internet. It is possible that the computer receives the transferred program, and installs the program in a storage medium such as a built-in hard disk or the like.

Moreover, it is also possible that the system, which has been described in the exemplary embodiment mentioned above, has structure of a logical combination of plural apparatuses, and has a configuration in which functions of each apparatus are intermingled.

The whole or part of the exemplary embodiments disclosed above can be described as, but not limited to, the following supplementary notes.

(Supplementary note 1 )

A wavelength path control system comprising:

a path computation means for computing which existing wavelength path is needed to be monitored when receiving a request for setting a new wavelength path or a request for configuring a wavelength path from a node;

a monitoring means for monitoring signal quality of the existing wavelength path needed to be monitored and the new wavelength path; and

a wavelength path control means for controlling to continue or stop setting the new wavelength path or configuring the wavelength path, based on the signal quality monitored by the monitoring management means. (Supplementary note 2)

The wavelength path control system according to supplementary note 1 , wherein the existing wavelength path needed to be monitored is an influenced existing wavelength path which is influenced by setting the new wavelength path or configuring the wavelength path.

(Supplementary note 3)

The wavelength path control system according to supplementary note 1 or 2, wherein the monitoring means for monitoring the signal quality at a receiver node of the existing wavelength path and the new wavelength path.

(Supplementary note 4)

The wavelength path control system according to any one of supplementary notes 1 to 3 ,

wherein the monitoring means for sending an alarm to the wavelength path control means when the monitoring means detecting degradation of signal quality.

(Supplementary note 5)

The wavelength path control system according to any one of supplementary notes 1 to 4,

wherein the monitoring means for detecting degradation of signal quality when a ratio of corrected bits during a given period to total data bits received during a given period is more than a threshold value.

(Supplementary note 6)

The wavelength path control system according to any one of supplementary notes 1 to 5,

wherein the monitoring means for detecting the ratio of corrected bits during a given period to total data bits received during a given period is equal or less than the threshold value.

(Supplementary note 7)

The wavelength path control system according to supplementary note 5 or 6, wherein the corrected bits are corrected by FEC (Forward Error Correction).

(Supplementary note 8) A wavelength path control method comprising:

computing which existing wavelength path is needed to be monitored when receiving a request for setting a new wavelength path or a request for configuring a wavelength path from a node;

monitoring signal quality of the existing wavelength path needed to be monitored and the new wavelength path; and

controlling to continue or stop setting the new wavelength path or configuring the wavelength path, based on the signal quality monitored.

(Supplementary note 9)

The wavelength path control method according to supplementary note 8, further comprising: .

wherein the existing wavelength path needed to be monitored is an influenced existing wavelength path which is influenced by setting the new wavelength path or configuring the wavelength path.

(Supplementary note 10)

The wavelength path control method according to supplementary note 8 or 9, further comprising:

monitoring the signal quality at a receiver node of the existing wavelength path and the new wavelength path.

(Supplementary note 11 )

The wavelength path control method according to any one of supplementary notes 8 to 10, further comprising:

sending an alarm when the monitoring unit detecting degradation of signal quality.

(Supplementary note 12)

The wavelength path control method according to any one of supplementary notes 8 to 11 , further comprising:

detecting degradation of signal quality when a ratio of corrected bits during a given period to total data bits received during a given period is more than a threshold value.

(Supplementary note 13) The wavelength path control method according to any one of supplementary notes 8 to 12, further comprising:

detecting the ratio of corrected bits during a given period to total data bits received during a given period is equal or less than the threshold value.

(Supplementary note 14)

The wavelength path control method according to supplementary note 12 or 13, wherein the corrected bits are corrected by FEC (Forward Error Correction).

(Supplementary note 15)

A storage medium for storing a wavelength path control program comprising: a computing process computing which existing wavelength path is needed to be monitored when receiving a request for setting a new wavelength path or a request for configuring a wavelength path from a node;

a monitoring process monitoring signal quality of the existing wavelength path needed to be monitored and the new wavelength path; and

a controlling process to continue or stop setting the new wavelength path or configuring the wavelength path, based on the signal quality monitored.

(Supplementary note 16)

The storage medium for storing the wavelength path control program according to supplementary note 15, further comprising:

(Supplementary note 17)

The storage medium for storing the wavelength path control program according to supplementary note 15 or 16, further comprising:

a monitoring process monitoring the signal quality at a receiver node of the existing wavelength path and the new wavelength path.

(Supplementary note 18)

The storage medium for storing the wavelength path control program according to any one of supplementary notes 15 to 17, further comprising: a sending process sending an alarm when the monitoring unit detecting degradation of signal quality.

(Supplementary note 19)

The storage medium for storing the wavelength path control program according to any one of supplementary notes 15 to 18, further comprising:

a detecting process detecting degradation of signal quality when a ratio of corrected bits during a given period to total data bits received during a given period is more than a threshold value.

(Supplementary note 20)

The storage medium for storing the wavelength path control program according to any one of supplementary notes 15 to 19, further comprising:

a detecting process detecting the ratio of corrected bits during a given period to total data bits received during a given period is equal or less than the threshold value.

(Supplementary note 21 )

The storage medium for storing the wavelength path control process according to supplementary note 19 or 20,

wherein the corrected bits are corrected by FEC (Forward Error Correction).

(Supplementary note 22)

A wavelength path control program comprising:

a computing process computing which existing wavelength path is needed to be monitored when receiving a request for setting a new wavelength path or a request for configuring a wavelength path from a node;

a controlling process controlling to continue or stop setting the new wavelength path or configuring the wavelength path, based on the signal quality monitored. (Supplementary note 23)

The wavelength path control program according to supplementary note 22, further comprising:

(Supplementary note 24)

The wavelength path control program according to supplementary note 22 or 23, further comprising:

(Supplementary note 25)

The wavelength path control program according to any one of supplementary notes 22 to 24, further comprising:

a sending process sending an alarm when the monitoring unit detecting degradation of signal quality.

(Supplementary note 26)

The wavelength path control program according to any one of supplementary notes 22 to 25, further comprising:

(Supplementary note 27)

The wavelength path control process according to any one of supplementary notes 22 to 26, further comprising:

(Supplementary note 28)

The wavelength path control program according to supplementary note 26 or 27, wherein the corrected bits are corrected by FEC (Forward Error Correction).

Reference Signs List

100 Node

110 Optical amplifier

120 Wavelength DEMUX/MUX and switching unit 130 Transponder

131 WDM transmitter

132 WDM receiver

133 Signal quality monitoring unit

134 Local signal receiver

135 Local signal transmitter

140 Monitoring management unit

141 Signal quality database

142 Alarm decision unit

150 Nodal control unit

151 Signal quality alarm control unit

152 Wavelength management unit

00 Optical fiber

00 NMS

00 Monitoring point computation unit

500, 1003 Wavelength path (WP) control unit

00 Wavelength path database (WPDB)

800, 801 , 802, 803, 804, 805, 806, 807, 808, 809, 810, 811 , 812, 813, 814, 815, 816,7 Message

1000 Wavelength path control system

1001 Path computation unit

1002 Monitoring unit

Claims

[Claim 1 ]

A wavelength path control system comprising:

a wavelength path control means for controlling to continue or stop setting the new wavelength path or configuring the wavelength path, based on the signal quality monitored by the monitoring management unit.

[Claim 2]

The wavelength path control system according to claim 1 ,

[Claim 3]

The wavelength path control system according to claim 1 or 2,

wherein the monitoring means for monitoring the signal quality at a receiver node of the existing wavelength path and the new wavelength path.

[Claim 4]

The wavelength path control system according to any one of claims 1 to 3, wherein the monitoring means for sending an alarm to the wavelength path control unit when the monitoring unit detecting degradation of signal quality.

[Claim 5]

The wavelength path control system according to any one of claims 1 to 4, wherein the monitoring means for detecting degradation of signal quality when a ratio of corrected bits during a given period to total data bits received during a given period is more than a threshold value.

[Claim 6] The wavelength path control system according to any one of claims 1 to 5, wherein the monitoring means for detecting the ratio of corrected bits during a given period to total data bits received during a given period is equal or less than the threshold value.

[Claim 7]

The wavelength path control system according to claim 5 or 6,

wherein the corrected bits are corrected by FEC (Forward Error Correction).

[Claim 8]

A wavelength path control method comprising:

[Claim 9]

The wavelength path control method according to claim 8, further comprising: wherein the existing wavelength path needed to be monitored is an influenced existing wavelength path which is influenced by setting the new wavelength path or configuring the wavelength path.

[Claim 10]

The wavelength path control method according to claim 8 or 9, further comprising: monitoring the signal quality at a receiver node of the existing wavelength path and the new wavelength path.

[Claim 11 ]

The wavelength path control method according to any one of claims 8 to 10, further comprising:

[Claim 12] The wavelength path control method according to any one of claims 8 to 1 1 , further comprising:

[Claim 13]

The wavelength path control method according to any one of claims 8 to 12, further comprising:

[Claim 14]

The wavelength path control method according to claim 12 or 13,

wherein the corrected bits are corrected by FEC (Forward Error Correction).

[Claim 15]

[Claim 16]

The storage medium for storing the wavelength path control program according to claim 15, further comprising:

[Claim 17]

The storage medium for storing the wavelength path control program according to claim 15 or 16, further comprising:

[Claim 18]

The storage medium for storing the wavelength path control program according to any one of claims 15 to 17, further comprising:

[Claim 19]

The storage medium for storing the wavelength path control program according to any one of claims 15 to 18, further comprising:

[Claim 20]

The storage medium for storing the wavelength path control program according to any one of claims 15 to 19, further comprising:

a detecting process detecting the ratio of corrected bits during a given period to total data bits received during a given period is equal or less than the threshold value. [Claim 21]

The storage medium for storing the wavelength path control process according to claim 19 or 20,

wherein the corrected bits are corrected by FEC (Forward Error Correction).