JP4983679B2 - Wavelength path route determination device, wavelength path route determination method and program - Google Patents

Description

  The present invention relates to an optical network control technique for setting a wavelength path, and more particularly to an apparatus for determining a path of a wavelength path to be set between two optical nodes.

  Non-patent document 1 is cited as a method for determining the path of a wavelength path set between two optical nodes. Here, a network is described in which a cross-connect device is used to set a path in units of VC (Virtual Container) 4 or their concatenation. In this method, when it is necessary to set a VC4 path between two nodes, the network control apparatus extracts a link having a free capacity of VC4 and connects the two nodes by the extracted link. To determine the path of the set path.

  In the method described in Non-Patent Document 1, when it is necessary to set a VC4 path between two nodes, the network control apparatus extracts a link having a free capacity of VC4, and uses the extracted link to perform the 2 The route of the set path is determined by obtaining the route connecting the nodes.

  As the required transmission band is further increased in capacity, an optical communication system is being studied in which the wavelength in a wavelength division multiplexing system is used as a unit of path and a wavelength path is set as necessary. In such an optical communication system, it is assumed that the method described in Non-Patent Document 1 is applied to route determination when setting a wavelength path. In this case, the path determination device extracts an unused wavelength in the wavelength multiplexing link, and uses only the same wavelength among the unused wavelengths to connect the two nodes serving as wavelength path termination points. Will be asked.

  However, unlike the network configuration in Non-Patent Document 1, in a network in which a wavelength path is set, a cross-connect is performed at the wavelength level, and optical-electrical-optical conversion is not performed for each link. May not be able to withstand actual use, ie, very high errors may be observed at the receiving end.

  In order to solve such a problem, in a full transparent network where there is no 3R at an intermediate node, the degree of quality degradation that the optical signal undergoes over the entire path based on quality determination information that indicates the degree of quality degradation that the optical signal that passes through And a technology for linking a wavelength path calculation device that determines a route from a quality degradation degree less than a predetermined value and an NMS (operation management system) has been proposed.

A. D'Alessandro et al, “ASON implementation in Telecom Italy backbone network”, [online], October 16, 2006, Telecom Italy, [March 04, 2008 search], Internet <URL: http: // www . oiforum. com / public / documents / 061016-Telecom% 20 Italy. pdf>

  The current wavelength service is provided through a procedure in which an optical network is designed off-line, materials are procured from vendors, and construction and opening tests are performed. Therefore, the time required for providing the service is very long. In order to provide services such as future time lending, it is impractical to perform the above procedures, and it is necessary to improve these procedures and reduce the time until service provision. On the other hand, in current optical networks, surplus 3Rs (regenerators) and transponders are often mounted on nodes without being used for demand estimation and maintenance.

  It is possible to improve the line quality by utilizing this surplus 3R. However, in the cooperation technology between the NMS and the wavelength path calculation device related to the above-mentioned full transparent network, the surplus 3R is not utilized.

  Accordingly, the present invention provides a wavelength path route determination device that determines a wavelength path route that ensures the quality while efficiently utilizing the existing 3R in an optical network in which 3R is pre-arranged in anticipation of demand, An object of the present invention is to provide a wavelength path route determination method and program.

According to the wavelength path route determination device of the present invention,
The topology information indicating each wavelength multiplexing link in the network and the optical nodes at both ends thereof, the wavelength state information indicating the use state of the wavelength included in each wavelength multiplexing link, and each wavelength multiplexing link and each optical node are passed. A wavelength path route determination device that determines a wavelength path route to be set by quality determination information indicating a degree of quality degradation of an optical signal and node attribute information indicating presence / absence of a regenerative repeater in each optical node, Based on the topology information and the wavelength state information, based on the topology information, the quality determination information, and the node attribute information, a means for determining whether or not the path connecting the two optical nodes can be connected with the same unused wavelength, For the path connecting the two optical nodes, quality degradation occurs when the regenerative repeater is not used and when it is used. A means for determining the degree and determining whether the degree of quality degradation is less than a predetermined threshold and the optical nodes at both ends of the wavelength path to be set can be connected with the same unused wavelength, and regenerative relaying is possible. There is a first selection means for selecting a wavelength path path to be set from paths whose quality degradation is less than a predetermined threshold without using an apparatus, and a wavelength path path selected by the first selection means. If not, from the path that can be connected between the optical nodes at both ends of the wavelength path to be set with the same unused wavelength, and the degree of quality degradation is less than a predetermined threshold using the regenerative repeater, Second selection means for selecting the path of the wavelength path to be set.

According to another embodiment of the wavelength path routing device of the present invention,
The second selection means is also preferably means for selecting a route that uses the least number of regenerative repeaters.

According to the wavelength path route determination method of the present invention,
The topology information indicating each wavelength multiplexing link in the network and the optical nodes at both ends thereof, the wavelength state information indicating the use state of the wavelength included in each wavelength multiplexing link, and each wavelength multiplexing link and each optical node are passed. A wavelength path route determination method for determining a wavelength path route to be set by quality determination information indicating a degree of quality degradation of an optical signal and node attribute information indicating presence / absence of a regenerative repeater in each optical node, Based on the topology information and the wavelength state information, a step of determining whether or not the path connecting the two optical nodes can be connected with the same unused wavelength, and based on the topology information, the quality determination information, and the node attribute information, When the regenerative repeater is not used for the path connecting the two optical nodes, the degree of quality degradation is obtained and The first determination step for determining whether or not the degree is less than a predetermined threshold and the optical nodes at both ends of the wavelength path to be set can be connected with the same unused wavelength, and the regenerative repeater is used. First, the first selection step for selecting the path of the wavelength path to be set from the paths whose quality degradation is less than the predetermined threshold, and the topology selected in the first selection step does not exist Based on the information, the quality determination information, and the node attribute information, the degree of the quality degradation is less than a predetermined threshold when the regenerative repeater is used for the path connecting the two optical nodes. The second determination step for determining whether or not and the optical nodes at both ends of the wavelength path to be set can be connected by the same unused wavelength, and the degree of quality degradation using the regenerative repeater From the path it is less than a predetermined threshold value, and a second selection step of selecting a path of a wavelength path to be set.

  According to the program of the present invention, a computer is caused to function as the wavelength path route determination device.

  In a wide-area translucent network configured by ROADM or WXC, when providing a time lending wavelength service or the like, it is possible to calculate a path including 3R that is currently available. For this reason, it is possible to select a route whose quality degradation is less than a predetermined value, and it is possible to quickly provide a data transfer service in which signal quality is ensured.

  The best mode for carrying out the present invention will be described in detail below with reference to the drawings.

  FIG. 1 shows an outline of the configuration of a network system according to the present invention. This system includes an operation management system 1, a wavelength path route determination device 2, and a translucent network 3 controlled by GMPLS.

  The network 3 includes a plurality of optical nodes 4, and the optical nodes 4 are connected to each other by one or more wavelength division multiplexing (WDM) links. In addition, compared to the conventional opaque network (where all switching nodes have OEO), the network 3 can reduce the number of OEO by placing 3Rs (regenerators) at the right place, making it cost effective and wide area deployment. It is also a possible optical network. The optical node 4 has a function of cross-connecting each wavelength in each WDM link to be connected. Under the control from the operation management system 1, the optical node 4 has a function in two designated WDM links. Connect or disconnect the specified wavelength. Although not shown, 3R is mounted on some optical nodes 4. 3R is a kind of regenerative repeater, and enables optical signals to be transmitted with high quality by amplifying, regenerating, and retiming optical signals. For example, light is converted into an electric signal, amplified and shaped, and then converted into light again.

  The operation management system 1 is a device that receives a wavelength path setting request from an operator who requests a network path (1: path setting request) and sets a wavelength path. The operation management system 1 includes a network database, and this network database holds link information, topology information, quality determination information, and node attribute information for the network 3. Here, the link information is attribute information (for example, wavelength state information, link OSNR, link PMD, link NLPS, etc.) between the optical nodes 4 in the network 3. The wavelength state information will be described later. The topology information is information for specifying how a plurality of optical nodes 4 in the network 3 are connected. For each WDM link, the included wavelengths, the optical nodes 4 and interfaces at both ends, and the like. It contains information that identifies The quality determination information is information indicating the degree of quality degradation of an optical signal passing through each WDM link and each optical node 4 in the network. In this embodiment, optical signal-to-noise ratio information (OSNR), It includes polarization mode dispersion information (PMD), amount of nonlinear degradation, and chromatic dispersion as necessary. When chromatic dispersion compensation is performed in the network 3, it is not necessary to include chromatic dispersion information in the quality determination information. However, when chromatic dispersion compensation is not performed in the network 3, the chromatic dispersion information is also determined in quality. It is preferably used as information. Furthermore, other quality parameters can be used as quality determination information. The node attribute information is information relating to the optical node 4 in the network 3, and in this embodiment is information indicating whether or not the optical node 4 has 3R.

  When the operation management system 1 receives the path setting request, in addition to the requested path condition (designation of the optical node 4 at both ends of the wavelength path, etc.), link information, topology information, quality determination information in the network database, The node attribute information is notified to the wavelength path route determination device 2 (2: notification of link information, topology information, etc.).

  When setting a new wavelength path, the wavelength path route determination device 2 determines an optimal wavelength path route based on the above information. The determination of this wavelength path will be described in detail later. The determined optimum wavelength path is notified to the operation management system 1 (3: path calculation result notification).

  The operation management system 1 returns the path calculation result to the operator (4: return path calculation result), issues a path setting request to the initiator node (5: provisioning), and controls the setting of the wavelength path of the notified wavelength.

  FIG. 2 shows a functional block diagram of the wavelength path route determination device 2 according to the present invention. According to FIG. 2, the wavelength path route determination device 2 includes a wavelength continuity determination unit 21, a quality determination unit 22, a selection unit 23, and a communication unit 24 that performs communication processing with the operation management system 1. .

  Based on the topology information and link information, the wavelength continuity determination unit 21 determines whether or not a path connecting two given optical nodes can be connected with the same unused wavelength.

  FIG. 4 is a diagram showing wavelength state information for the simplified network 3 shown in FIG. The wavelength state information is information for specifying a wavelength that can be used for a new wavelength path among wavelengths in each WDM link. In FIG. 4, CH (channels) 1 and 3 of the WDM link 41 are new. It can be used for the wavelength path, and it is shown that CH2 and CH3 of the WDM link 42 can be used for the new wavelength path. Note that each CH corresponds to a predetermined wavelength, and channels with the same number correspond to the same wavelength.

  For example, in the state where the topology information corresponding to the configuration of FIG. 3 and the wavelength state information shown in FIG. 4 are stored in the network database, the path from the optical node 31 to the optical node 33 via the optical node 32 is When given to the wavelength continuity determination unit 21, since CH3 of the WDM link 41 and the WDM link 42 are both unused, the wavelength continuity determination unit 21 determines that connection is possible using the same unused wavelength.

  Based on the topology information, quality determination information, and node attribute information, the quality determination unit 22 first determines the degree of quality degradation in an environment without 3R (full transparency) for a path connecting two given optical nodes. It is determined whether or not the route satisfies the constraint condition, that is, whether or not the degree of quality degradation of the route is less than a predetermined threshold value, and is stored as a route candidate. If this route candidate does not exist, the degree of quality degradation is obtained for the above route in an environment with 3R, and it is determined whether or not the route satisfies the constraint condition, and is stored as a route candidate.

  Here, obtaining the degree of quality degradation in an environment with 3R means obtaining the degree of quality degradation for all nodes with 3R, with or without 3R. To do. For example, if node A and node B have 3R, node A uses 3R, node B does not use 3R, node A does not use 3R, node B uses 3R, A is that 3R is used, and the node B also obtains the degree of quality deterioration with respect to three patterns that use 3R.

  When there are a plurality of pieces of quality determination information to be used, the quality determination unit 22 performs determination based on each threshold for all information. As the quality determination information, it is preferable to use all of OSNR information, PMD information, nonlinear deterioration amount, and chromatic dispersion, as described in the present embodiment, but only OSNR information, OSNR information, and PMD information, Combinations of these may be used.

  When the operation management system 1 receives the designation of optical nodes that are both ends of the wavelength path to be set, the selection unit 23 is configured to receive both ends of the wavelength path to be set based on the determination by the wavelength continuity determination unit 21 and the quality determination unit 22. Are identified by a path that can be connected with the same wavelength that is not used, and the degree of quality degradation is less than a preset threshold value. From these paths, a path to be used for the wavelength path to be set is 1 Select one. In addition, when there are a plurality of pieces of quality determination information to be used, a route whose quality degradation level is less than a preset threshold value is that the route quality degradation values required for each information are all less than the respective threshold values. Means a route that is In addition, when there are a plurality of routes that satisfy the condition in an environment without 3R, it is desirable to select a route with the smallest number of optical nodes that pass through. On the other hand, if there are multiple paths that satisfy the conditions in an environment with 3R, 1) a path with a smaller number of 3Rs, 2) a path with a smaller link wavelength usage rate, and 3) a digital section (transponder-3R) The route is narrowed down in the order of the route having the largest OSNR. That is, first, narrowing is performed with a route satisfying 1), and if there are still a plurality of routes, narrowing is performed with a route satisfying 2). If there are still a plurality of routes, narrowing down is performed with a route satisfying 3). If there are still a plurality of paths, the path with the smallest wavelength used is selected.

  As the number of 3Rs increases, the quality of the route improves. However, if a large amount of 3R is used for one route, 3R will be insufficient when the next route is calculated. Therefore, the number of 3Rs to be used is reduced as much as possible. In terms of cost, it is better to reduce the number of 3Rs. That is, a route including the minimum 3R necessary for maintaining quality is selected.

  FIG. 5 is a flowchart of the wavelength path route determination method in the wavelength path route determination device 2. First, the selection unit 23 uses the wavelength continuity determination unit 21 to search for all paths that connect with unused unused wavelengths between optical nodes that terminate a new wavelength path (S51). Subsequently, one route that has not been subjected to the processing of S53 is selected from the routes searched in S51 (S52), and the quality determination unit 22 is used to check whether the selected route satisfies the constraint condition in an environment where there is no 3R. It is determined whether or not the quality degradation degree of the selected route is less than a predetermined threshold (S53). Here, when the constraint condition is satisfied, that is, when it is less than the threshold value, the selected route is added to the route candidate (S54), and the constraint condition is determined for all the routes searched in S51 (S55). Confirms whether there is a route candidate (S56). If it exists, the route to be actually used is determined from the route candidates (S57), and the determined route and wavelength are notified to the operation management system 1 (S58). On the other hand, if it does not exist, all the search results are changed to unprocessed in order to search again (S59), and then one route that has not been processed in S61 is selected from the routes searched in S51. (S60) and using the quality determination unit 22, whether or not the selected route satisfies the constraint condition in an environment with 3R, that is, whether or not the quality degradation degree of the selected route is less than a predetermined threshold. Is determined (S61). Here, when the constraint condition is satisfied, that is, when the value is less than the threshold, the selected route is added to the route candidate (S62), and the constraint condition is determined for all the routes searched in S51 (S63). Determines a path to be actually used from the path candidates (S64), and notifies the operation management system 1 of the determined path and wavelength (S58). The operation management system 1 controls the setting of the wavelength path of the notified wavelength with respect to the initiator node on the notified path.

  In the flow chart described above, first, a route is searched for the same wavelength that can be used, and it is determined whether the searched route satisfies the quality. First, a route that satisfies the quality is searched, It may be determined whether or not the searched route can be connected with the same available wavelength.

  The wavelength path route determination device 2 according to the present invention can be realized by a computer program that causes a computer to function as each unit in FIG. This computer program is stored in a computer-readable storage medium or can be distributed via a network. Furthermore, the present invention can be realized not only by hardware and software but also by a combination thereof.

  Moreover, all the embodiments described above are illustrative of the present invention and are not intended to limit the present invention, and the present invention can be implemented in other various modifications and changes. Therefore, the scope of the present invention is defined only by the claims and their equivalents.

1 shows a schematic configuration of a network system according to the present invention. 1 shows a functional block diagram of a wavelength path route determination device according to the present invention. FIG. A simplified network is shown. Wavelength state information is shown. The flowchart of the route determination method of the wavelength path in a wavelength path route determination apparatus is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Operation management system 2 Wavelength path route determination apparatus 3 Network 21 Wavelength continuity determination part 22 Quality determination part 23 Selection part 24 Communication part 4, 31, 32, 33 Optical node 41, 42 WDM link

Claims (4)

The topology information indicating each wavelength multiplexing link in the network and the optical nodes at both ends thereof, the wavelength state information indicating the use state of the wavelength included in each wavelength multiplexing link, and each wavelength multiplexing link and each optical node are passed. A wavelength path route determination device that determines a wavelength path route to be set by quality determination information indicating a degree of quality degradation of an optical signal and node attribute information indicating presence / absence of a regenerative repeater in each optical node,
Means for determining whether or not connection is possible using the same unused wavelength for a path connecting two optical nodes based on topology information and wavelength state information;
Based on topology information, quality determination information, and node attribute information, each of a case where a regenerative repeater is not used and a case where a regenerative repeater is not used for a path connecting two optical nodes Means for determining the degree of quality degradation and determining whether the degree of quality degradation is less than a predetermined threshold;
From the path where the optical nodes at both ends of the wavelength path to be set can be connected by the same unused wavelength, and the degree of quality degradation is less than the predetermined threshold without using the regenerative repeater, the wavelength path to be set A first selection means for selecting a route;
When the path of the wavelength path selected by the first selection means does not exist, the optical nodes at both ends of the wavelength path to be set can be connected by the same unused wavelength, and a regenerative repeater is used. Second selecting means for selecting a path of a wavelength path to be set from paths whose quality degradation is less than a predetermined threshold;
A wavelength path routing device comprising:   The wavelength path route determination device according to claim 1, wherein the second selection unit is a unit that selects a route that uses the least number of regenerative repeaters. The topology information indicating each wavelength multiplexing link in the network and the optical nodes at both ends thereof, the wavelength state information indicating the use state of the wavelength included in each wavelength multiplexing link, and each wavelength multiplexing link and each optical node are passed. A wavelength path route determination method for determining a wavelength path route to be set by quality determination information indicating a degree of quality degradation of an optical signal and node attribute information indicating presence / absence of a regenerative repeater in each optical node,
Determining whether or not connection is possible using the same unused wavelength for a path connecting two optical nodes based on topology information and wavelength state information;
Based on topology information, quality determination information, and node attribute information, each of a case where a regenerative repeater is not used and a case where a regenerative repeater is not used for a path connecting two optical nodes A first determination step for determining a degree of quality deterioration and determining whether the degree of quality deterioration is less than a predetermined threshold;
From the path where the optical nodes at both ends of the wavelength path to be set can be connected by the same unused wavelength, and the degree of quality degradation is less than the predetermined threshold without using the regenerative repeater, the wavelength path to be set A first selection step of selecting a route;
When the route selected in the first selection step does not exist, based on the topology information, the quality determination information, and the node attribute information, when the regenerative repeater is used for the route connecting the two optical nodes, A second determination step of determining a degree of quality deterioration and determining whether the degree of quality deterioration is less than a predetermined threshold;
From the path where the optical nodes at both ends of the wavelength path to be set can be connected by the same unused wavelength and the degree of quality degradation is less than a predetermined threshold using the regenerative repeater, the wavelength path to be set A second selection step for selecting a route;
A wavelength path route determination method comprising:   A program that causes a computer to function as the wavelength path route determination device according to claim 1.

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