JP2016134664A - Optical network controller, optical communication system, and optical path setting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method capable of reducing the processing man-hours required in the relocation of an optical path for enhancing the frequency utilization efficiency, in an elastic optical network.SOLUTION: An optical network controller 100 has relocation optical path extraction means 110 for extracting a relocation object optical path among existing optical paths in an optical network, based on the attributes of a relocation optical path when relocated, and optical path relocation means 120 executing relocation processing for the relocation object optical path.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical network control device, an optical communication system, and an optical path setting method, and more particularly to an optical network control device, an optical communication system, and an optical path setting method using an elastic optical network method.

  The optical network provides a function of communicating the traffic of a client device via an optical fiber communication path that connects bases. Here, the optical network receives a client signal via an interface between the node device and the client device. Then, after multiplexing a plurality of client signals using various multiplexing systems, communication is performed via a larger-capacity optical fiber communication path. The multiplexing scheme includes a wavelength division multiplexing (WDM) scheme, a time division multiplexing (TDM) scheme, and an orthogonal frequency division multiplexing (OFDM) scheme.

  Furthermore, in recent years, a shift to a dynamic optical network in which large-capacity signal light transmitted from a node device is dynamically added, changed, or deleted according to traffic fluctuations of a client device has progressed. In such a dynamic optical network, a fragmented unused region (wavelength fragmentation) occurs in the arrangement of the wavelength slots of the optical fiber communication path as the operation time elapses. In order to realize high-efficiency use of an optical network, a technique for eliminating this wavelength fragmentation is indispensable.

  On the other hand, an elastic optical network system has been proposed in order to effectively use optical frequency resources. According to the elastic optical network method, a minimum frequency band corresponding to the transmission capacity of an optical signal is allocated to a path between nodes transmitting and receiving an optical signal on a network in which a plurality of nodes are connected by optical fibers. It is possible. In the elastic optical network system, the frequency band to be allocated can be flexibly determined according to the number of slots with a predetermined frequency width as one slot unit.

  Thus, according to the elastic optical network system, the required number of wavelength slots of the optical path can be changed according to the required capacity of traffic. As a result, it becomes possible to assign an optical path to surplus wavelength resources that could not be utilized in the conventional fixed grid network. As a result, the utilization efficiency of the optical network can be improved.

  An example of a technique for eliminating wavelength fragmentation in such an elastic optical network is described in Patent Document 1.

  The related optical network control device described in Patent Document 1 uses a basic bandwidth as a slot, and can set wavelength paths of different bandwidths using one slot or a plurality of slots consecutive in wavelength order. Used for networks. A related optical network control device includes holding means, determination means, and control means.

  The holding unit holds information for calculating wavelength path quality information. The determination means determines the state after the defragmentation process that prevents fragmentation of unused slots. Then, the control means transmits a control command for controlling the optical network to the optical network, and when it matches a predetermined condition, causes the determination means to determine the state after the defragmentation process.

  Here, the determining means sets the slot usage order, and moves the wavelength path when it can move to an unused slot that is adjacent to the wavelength path and has a higher usage order than the wavelength path. Further, when the wavelength path to be moved uses a plurality of slots, it is determined whether the number of used slots of the wavelength path can be reduced by changing the modulation format of the wavelength path in the moved slot. To do. The determination is made based on quality information calculated from information held by the holding means. As a result, when the number of used slots of the wavelength path can be reduced, the state after the defragmentation process is determined by reducing the number.

  With such a configuration, it is possible to execute effective defragmentation in an optical network in which wavelength paths with different bandwidths can be set.

JP 2014-155017 A

  In the related optical network control apparatus described above, each node apparatus has an optical link with a node apparatus having a different number. However, in the current optical network, a transition to a physical layer topology in which optical node devices are connected to each other by an optical fiber in a mesh shape is progressing. For mesh physical layer topologies, there are many relocation candidates that can eliminate wavelength fragmentation. In other words, there are many rearrangement candidates for the physical path of the optical path and the wavelength slot arrangement. In addition, in an elastic optical network in which the number of required wavelength slots for an optical path can be selected, the number of wavelength slots can be selected based on the communication path quality of the physical path. Therefore, the selection of the number of wavelength slots is further added as a parameter for searching for rearrangement candidates. As a result, the time required to calculate the optimal wavelength slot assignment increases under sequentially changing path conditions.

  As described above, the elastic optical network has a problem that the number of processing steps required for rearrangement of the optical path for improving the frequency utilization efficiency increases.

  An object of the present invention is an optical network control that solves the above-described problem that, in an elastic optical network, the number of processing steps required for rearrangement of an optical path for improving frequency utilization efficiency increases. An apparatus, an optical communication system, and an optical path setting method are provided.

  The optical network control device according to the present invention uses, as an attribute of a rearrangement optical path when rearrangement is performed, a rearrangement target optical path to be rearranged from existing optical paths that are existing optical paths in the optical network. A rearrangement optical path extraction unit that extracts based on the optical path, and an optical path rearrangement unit that executes rearrangement processing on the rearrangement target optical path.

  According to the optical path setting method of the present invention, the rearrangement target optical path to be rearranged from the existing optical paths that are existing optical paths in the optical network is set as an attribute of the rearrangement optical path when rearrangement is performed. Based on the extraction, the rearrangement process is executed for the rearrangement target optical path.

  According to the optical network control device, the optical communication system, and the optical path setting method of the present invention, even when the elastic optical network method is used, the optical path can be rearranged without increasing the number of processing steps. The frequency utilization efficiency can be improved.

It is a block diagram which shows the structure of the optical network control apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows schematic structure of the optical communication system which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the optical network control apparatus and optical node apparatus which comprise the optical communication system which concerns on the 2nd Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the optical network control apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows schematic structure of the optical network for demonstrating operation | movement of the optical network control apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows typically the use condition of the wavelength slot before the rearrangement process for demonstrating operation | movement of the optical network control apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows typically the use condition of the wavelength slot after the rearrangement process for demonstrating operation | movement of the optical network control apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the optical network control apparatus and optical node apparatus which comprise the optical communication system which concerns on the 3rd Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the optical network control apparatus which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the optical network control apparatus and optical node apparatus which comprise the optical communication system which concerns on the 4th Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the optical network control apparatus which concerns on the 4th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of an optical network control apparatus 100 according to the first embodiment of the present invention. The optical network control apparatus 100 includes a rearrangement optical path extraction unit 110 and an optical path rearrangement unit 120.

  The rearrangement optical path extraction unit 110 sets the rearrangement target optical path to be rearranged as an attribute of the rearrangement optical path when rearrangement is performed from existing optical paths that are existing optical paths in the optical network. Extract based on. The optical path rearrangement unit 120 executes a rearrangement process on the rearrangement target optical path extracted by the rearrangement optical path extraction unit 110.

  With such a configuration, according to the optical network control apparatus 100 of the present embodiment, the number of optical paths for performing the rearrangement process can be reduced. As a result, even when using an elastic optical network method in which the number of wavelength slots is added as an optical path setting parameter, frequency utilization efficiency can be improved by rearranging optical paths without increasing the number of processing steps. Can be planned.

  Here, the physical path of the rearranged optical path can be different from the physical path of the existing optical path.

  Further, the number of wavelength slots to which the rearranged optical path is assigned can be used as the attribute of the rearranged optical path. Here, when the rearranged optical path extraction unit 110 can allocate the rearranged optical path to a smaller number of wavelength slots than the number of wavelength slots to which the existing optical path is allocated, the existing optical path at this time Can be extracted as a rearrangement target optical path.

  In this case, as shown in FIG. 1, the rearranged optical path extraction unit 110 can be configured to include an alternative path search unit 111, a wavelength slot arrangement calculation unit 112, and a wavelength slot number determination unit 113. Further, the optical path rearrangement unit 120 may include an optical path reallocation unit 121 and an optical path allocation control unit 122.

  Here, the alternative route search unit 111 searches for an alternative route that is a physical route different from the physical route of the existing optical path. The wavelength slot arrangement calculation unit 112 calculates the arrangement of alternative wavelength slots that are wavelength slots that can be used in the alternative path. Then, the wavelength slot number determination unit 113 determines whether or not the rearranged optical path can be allocated to a number of alternative wavelength slots smaller than the number of wavelength slots to which the existing optical path is allocated.

  Further, when the wavelength slot number determination unit 113 determines that the rearrangement optical path can be allocated, the optical path reallocation unit 121 sets the existing optical path at this time as the rearrangement target optical path, and the rearrangement target light. Assign paths to alternate wavelength slots. Then, the optical path arrangement control unit 122 notifies the information on the rearrangement target optical path and the alternative wavelength slot to the optical node device configuring the optical network.

  In such a configuration, since the rearrangement process is performed only for the existing optical path in which the number of wavelength slots to be used is reduced by the rearrangement, it is possible to further improve the frequency utilization efficiency.

  Next, the optical path setting method according to the present embodiment will be described. In the optical path setting method according to this embodiment, first, rearrangement light when rearrangement target optical paths to be rearranged are rearranged from existing optical paths that are existing optical paths in the optical network. Extract based on path attributes. Then, a rearrangement process is executed for the rearrangement target optical path.

  Here, the physical path of the rearranged optical path can be different from the physical path of the existing optical path.

  Further, the number of wavelength slots to which the rearranged optical path is assigned can be used as the attribute of the rearranged optical path. Here, when a rearranged optical path can be allocated to a number of wavelength slots smaller than the number of wavelength slots to which an existing optical path is allocated, the existing optical path is extracted as a rearrangement target optical path. be able to.

  In this case, when extracting the rearrangement target optical path, an alternative route that is different from the physical route of the existing optical path is searched, and the arrangement of the alternative wavelength slot that is a wavelength slot that can be used in this alternative route is calculated. To do. And it can be set as the structure which determines whether a rearrangement optical path can be allocated to the number of alternative wavelength slots smaller than the number of the wavelength slots to which the existing optical path is allocated.

  At this time, when executing the rearrangement process for the rearrangement target optical path, when it is determined that the rearrangement optical path can be allocated, the existing optical path is set as the rearrangement target optical path, and the rearrangement target optical path is It can be assigned to an alternative wavelength slot.

  Furthermore, it is good also as a structure which notifies the information regarding a rearrangement object optical path and an alternative wavelength slot to the optical node apparatus which comprises an optical network.

  As described above, according to the optical network control device 100 and the optical path setting method of the present embodiment, even when the elastic optical network method is used, the optical path can be re-established without increasing the number of processing steps. The frequency utilization efficiency can be improved by the arrangement.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 2 shows a schematic configuration of the optical communication system 1000 according to the present embodiment. As shown in the figure, the optical communication system 1000 includes an optical network control device 1100 and an optical node device. FIG. 2 shows an example in which five optical node devices 1201 to 1205 are connected by an optical fiber communication path to constitute an optical network 1300.

  FIG. 3 shows the configurations of the optical network control device 1101 and the optical node device 1201 that constitute the optical communication system 1000 according to the present embodiment.

  The optical network control device 1101 includes a database unit 1110, a wavelength slot fragmentation detection unit 1120, an optical path rearrangement calculation unit 1130, and an optical path allocation control unit 1140.

  The database unit 1110 includes a request traffic DB (database) 1111, a network equipment DB 1112, and an optical path management DB 1113. The optical path rearrangement calculation unit 1130 includes an alternative path search unit 1131, a variable wavelength slot allocation calculation unit 1132, and a wavelength slot number reduction determination unit 1133.

  The optical node device 1201 includes a wavelength setting control unit 1211, a variable optical transponder 1212, a large granularity variable switching device 1213, and a route setting control unit 1214.

  The variable optical transponder 1212 can vary the center frequency and modulation method of the transmitted signal light and the slot width of the optical path.

  The large granularity variable switching device 1213 is connected to the optical fiber communication paths 1301 and 1302 constituting the optical network 1300, and changes the input / output path for each optical path. As the large granularity variable switching device 1213, for example, an optical cross-connect, a band-variable wavelength selective switch, or the like can be used.

  The optical network control device 1101 according to the present embodiment is configured to further include a wavelength slot fragmentation detection unit 1120 as a rearrangement detection unit in addition to the configuration of the optical network control device 100 according to the first embodiment. The rearrangement detection unit monitors the usage status of the wavelength slots in the optical fiber communication path constituting the optical network, and detects an opportunity to rearrange the existing optical path. The rearrangement detection means sends a detection notification to the rearrangement optical path extraction means 110 (see FIG. 1) when this trigger is detected. Then, the rearrangement light path extraction unit 110 performs a process of extracting the rearrangement target optical path when receiving the detection notification. Here, the wavelength slot fragmentation detection unit 1120 of the present embodiment is configured to detect when wavelength fragmentation has occurred as described above.

  The wavelength slot number reduction determination unit 1133 included in the optical network control device 1101 according to the present embodiment corresponds to the wavelength slot number determination unit 113 and the optical path reallocation unit 121 of the optical network control device 100 according to the first embodiment. ing.

  Further, the wavelength setting control unit 1211 and the route setting control unit 1214 included in the optical node device 1201 according to this embodiment operate as an optical node control unit. Here, the optical node control unit receives optical path rearrangement information including information on the rearrangement target optical path from the optical path rearrangement unit 120 (optical path arrangement control unit 1140). Based on the optical path rearrangement information, the variable optical transponder 1212 and the large granularity variable switching device 1213 are controlled.

  Next, the operation of the optical network control apparatus 1101 according to this embodiment will be described. FIG. 4 is a flowchart for explaining the operation of the optical network control apparatus 1101 according to this embodiment.

  In the optical network control device 1101, the wavelength slot fragmentation detection unit 1120 monitors the usage status of the wavelength slot in the optical fiber communication path (step S211). When the wavelength slot fragmentation detection unit 1120 detects that wavelength fragmentation has occurred in the optical fiber communication path 1301 in the optical network (step S212), the wavelength slot number in the wavelength fragmentation region and the optical fiber communication path ID are rearranged in the optical path. The calculation unit 1130 is notified (step S213). Here, the wavelength fragmentation region is determined according to the policy of the communication carrier. Specifically, for example, an area where the number of empty (unused) wavelength slots in the optical fiber communication path is a predetermined value or less, an area where there are no empty wavelength slots over a plurality of hops, and the like can be designated as the wavelength fragmentation area.

  After receiving the notification from the wavelength slot fragmentation detection unit 1120, the optical path rearrangement calculation unit 1130 reads an optical path adjacent to the wavelength fragmentation region from the optical path management DB 1113 (step S214). The alternative route search unit 1131 included in the optical path rearrangement calculation unit 1130 searches for the shortest route connecting the start point optical node and the end point optical node of the optical path as an alternative route (step S215).

  The variable wavelength slot arrangement calculation unit 1132 calculates a wavelength slot arrangement that can be used in the shortest path searched by the alternative path search unit 1131. Specifically, the required number of wavelength slots and the modulation method used at that time are determined (step S216).

  The wavelength slot number reduction determination unit 1133 determines whether or not the required number of wavelength slots of the optical path can be reduced by passing through the alternative path (step S217). At this time, the wavelength slot number reduction determination unit 1133 determines whether or not the modulation method can be changed based on the communication quality of the physical path that can be taken before and after the optical path reallocation. If it is determined that the modulation method can be changed, it is determined that the number of wavelength slots can be reduced (step S217 / YES), and the optical path is assigned to an available empty wavelength slot on the alternative path (step S218). ). When the wavelength slot number reduction determination unit 1133 determines that the number of wavelength slots cannot be reduced (NO in step S217), the variable wavelength slot arrangement calculation unit 1132 uses the current physical path to which the optical path is assigned. The possible wavelength slot arrangement may be calculated.

  The optical path rearrangement calculation unit 1130 determines whether or not there is an unassigned traffic request (step S219). That is, it is determined whether or not there is an unprocessed optical path among the optical paths to be rearranged. When there is an unprocessed optical path (step S219 / YES), the optical path rearrangement calculation unit 1130 repeats the processing from step S214 to step S218.

  The above-described processing is executed for all optical paths adjacent to the wavelength fragmentation region. When there is no unprocessed optical path (step S219 / NO), the optical path placement control unit 1140 notifies each optical node device of the optical path reset result (step S220), and ends the process. .

  Next, the optical path rearrangement result by the optical network control apparatus 1101 described above will be described with reference to FIGS. 5A, 5B, and 5C.

  In the optical network 1300 shown in FIG. 5A, before the relocation process, the physical path from the optical node device 1201 to the optical node device 1205 via the optical node device 1202, the optical node device 1203, and the optical node device 1204 is changed. An optical path P201 is arranged. The use situation of the wavelength slot at this time is shown in FIG. 5B.

  The alternative path search unit 1131 searches for the shortest path connecting the optical node device 1201 that is the start optical node of the optical path P201 and the optical node device 1205 that is the end optical node, and directly connects the optical node device 1201 and the optical node device 1205. A physical route is used as an alternative route.

  If the wavelength slot number reduction determination unit 1133 determines that the required number of wavelength slots can be reduced by passing through this alternative path, the wavelength slot number reduction determination unit 1133 allocates the available free wavelength slot on the alternative path as an optical path P202 as shown in FIG. 5C. . At this time, the wavelength slot number reduction determination unit 1133 performs the rearrangement process only for the optical path in which the number of wavelength slots to be used is reduced by the rearrangement. Can be improved.

  Note that if an available wavelength slot is not found in the shortest path, the alternative path search unit 1131 may search for the kth shortest path using, for example, a kth shortest path search algorithm.

  In some cases, priorities are set for optical paths in an optical network. Since an optical path with a higher priority is highly important, it may be excluded from reassignment in order to avoid communication interruption due to reassignment of the optical path. In that case, only the optical paths whose optical path priority is below a certain value are extracted from the optical path management DB 1113 and are to be rearranged. Here, the fixed value of the priority can be determined by, for example, the communication carrier.

  The optical path arrangement control unit 1140 notifies the wavelength setting control unit 1211 included in the optical node devices 1201 to 1205 included in the optical network 1300 of the wavelength slot number of the optical path to be reset. Further, the route setting control unit 1214 is notified of the route setting information of the large-grain variable switching device 1213 regarding the alternative route. Based on the notification, the wavelength setting control unit 121 controls the center frequency and modulation method of the signal light transmitted from the variable optical transponder 1212, and controls the setting of the wavelength slot that passes through the large-grain variable switching device 1213. On the other hand, the route setting control unit 1214 changes the optical fiber communication path connected to the variable optical transponder 1212 from the optical fiber communication path 1301 used for the current path to the optical fiber communication path 1302 used for the alternative path. The large grain size variable switching device 1213 is controlled. Thereby, it can switch to an alternative path | route.

  Wavelength fragmentation can be eliminated by the operation of the optical network control apparatus 1101 according to this embodiment described above. Furthermore, the wavelength slot number reduction determination unit 1133 performs an operation for eliminating the wavelength fragmentation only for the optical path that can reduce the number of wavelength slots. Therefore, it is possible to reduce work time and work man-hours while minimizing the risk of communication interruption during work. That is, it is possible to improve the network usage efficiency at high speed without impairing the reliability of the network.

  As described above, according to the optical network control apparatus 1101 and the optical communication system of the present embodiment, even when the elastic optical network method is used, the optical path is rearranged without increasing the number of processing steps. Thus, the frequency utilization efficiency can be improved.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. FIG. 6 shows the configuration of the optical network control device 1102 and the optical node device 1201 constituting the optical communication system according to the present embodiment.

    The optical network control apparatus 1102 includes a database unit 1110, a wavelength slot fragmentation detection unit 1120, an optical path rearrangement calculation unit 1130, and an optical path allocation control unit 1140.

  The database unit 1110 is configured to include a rearranged optical path management DB 1114 in addition to the request traffic DB 1111, the network equipment DB 1112, and the optical path management DB 1113. The optical path rearrangement calculation unit 1130 includes an optical path rearrangement order calculation unit 1134 in addition to the alternative path search unit 1131, the variable wavelength slot arrangement calculation unit 1132, and the wavelength slot number reduction determination unit 1133. did.

  Here, the rearrangement optical path management DB 1114 corresponds to the rearrangement optical path storage unit, and stores information on a plurality of rearrangement target optical paths. The optical path rearrangement order calculation unit 1134 corresponds to the rearrangement order determination unit, and determines the order in which the rearrangement process is executed for a plurality of rearrangement target optical paths based on the attributes of the rearrangement target optical paths. The optical path rearrangement calculation unit 1130 is configured to execute the rearrangement process based on this order. The attribute of the rearrangement target optical path can be any of the number of wavelength slots to which the rearrangement target optical path is allocated, the physical path length of the rearrangement target optical path, and the number of hops of the rearrangement target optical path. .

  Next, the operation of the optical network control apparatus 1102 according to the present embodiment will be described. FIG. 7 is a flowchart for explaining the operation of the optical network control apparatus 1102 according to the present embodiment.

  In the optical network control apparatus 1102, the wavelength slot fragmentation detection unit 1120 monitors the usage status of the wavelength slot in the optical fiber communication path (step S211). When the wavelength slot fragmentation detection unit 1120 detects that wavelength fragmentation has occurred in the optical fiber communication path 1301 in the optical network (step S212), the wavelength slot number in the wavelength fragmentation region and the optical fiber communication path ID are rearranged in the optical path. The calculation unit 1130 is notified (step S213).

  After receiving the notification from the wavelength slot fragmentation detection unit 1120, the optical path rearrangement calculation unit 1130 reads an optical path adjacent to the wavelength fragmentation region from the optical path management DB 1113 (step S214). The alternative route search unit 1131 included in the optical path rearrangement calculation unit 1130 searches for the shortest route connecting the start point optical node and the end point optical node of the optical path as an alternative route (step S215).

  The variable wavelength slot arrangement calculation unit 1132 calculates a wavelength slot arrangement that can be used in the shortest path searched by the alternative path search unit 1131. Specifically, the required number of wavelength slots and the modulation method used at that time are determined (step S216).

  The wavelength slot number reduction determination unit 1133 determines whether or not the required number of wavelength slots of the optical path can be reduced by passing through the alternative path (step S217). When it is determined that the number of wavelength slots can be reduced (step S217 / YES), wavelength allocation information such as the physical path of the optical path and the required number of wavelength slots is stored in the rearranged optical path management DB 1114 (step S311).

  The optical path rearrangement calculation unit 1130 determines whether or not there is an unassigned traffic request (step S219). That is, it is determined whether or not there is an unprocessed optical path among the optical paths to be rearranged. When there is an unprocessed optical path (step S219 / YES), the optical path rearrangement calculation unit 1130 repeats the processing from step S214 to step S311.

  The above-described processing is executed for all optical paths adjacent to the wavelength fragmentation region. When there is no unprocessed optical path (step S219 / NO), the optical path rearrangement order calculation unit 1134 rearranges the wavelength allocation order of the optical paths stored in the rearrangement optical path management DB 1114 (step S219). S312). Then, the optical paths are assigned to available empty wavelength slots on the alternative route in the rearranged order (step S313).

  Thereafter, the optical path arrangement control unit 1140 notifies each optical node device of the result of resetting the optical path (step S220), and the process ends.

  The wavelength allocation order described above is, for example, the shortest path order of the shortest path length of the optical path, the ascending order of the number of hops of the optical path, or the order in which the operator of the communication carrier can easily change the setting. Is possible. In this way, by adopting the processing for rearranging the wavelength allocation order of the optical paths, it is possible to relocate from the optical path with a large reduction in the number of required wavelength slots, so that highly efficient optical path accommodation is possible. Become.

  Note that if an available wavelength slot is not found in the shortest path, the alternative path search unit 1131 may search for the kth shortest path using, for example, a kth shortest path search algorithm.

  The optical path arrangement control unit 1140 notifies the wavelength setting control unit 1211 included in the optical node devices 1201 to 1205 included in the optical network 1300 of the wavelength slot number of the optical path to be reset. Further, the route setting control unit 1214 is notified of the route setting information of the large-grain variable switching device 1213 regarding the alternative route. Based on the notification, the wavelength setting control unit 1211 controls the center frequency and modulation method of the signal light transmitted from the variable optical transponder 1212, and controls the setting of the wavelength slot that passes through the large-grain variable switching device 1213. On the other hand, the route setting control unit 1214 changes the optical fiber communication path connected to the variable optical transponder 1212 from the optical fiber communication path 1301 used for the current path to the optical fiber communication path 1302 used for the alternative path. The large grain size variable switching device 1213 is controlled. Thereby, it can switch to an alternative path | route.

  Wavelength fragmentation can be eliminated by the operation of the optical network control apparatus 1102 according to the present embodiment described above. Furthermore, the wavelength slot number reduction determination unit 1133 performs an operation for eliminating the wavelength fragmentation only for the optical path that can reduce the number of wavelength slots. Therefore, it is possible to reduce work time and work man-hours while minimizing the risk of communication interruption during work. That is, it is possible to improve the network usage efficiency at high speed without impairing the reliability of the network.

  As described above, according to the optical network control device 1102 and the optical communication system of the present embodiment, even when the elastic optical network method is used, the optical path is rearranged without increasing the number of processing steps. Thus, the frequency utilization efficiency can be improved.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. FIG. 8 shows the configuration of the optical network control device 1103 and the optical node device 1201 constituting the optical communication system according to the present embodiment.

    The optical network control apparatus 1103 includes a database unit 1110, an optical fiber communication path congestion detection unit 1150, an optical path rearrangement calculation unit 1130, and an optical path allocation control unit 1140. The optical network control device 1103 according to the present embodiment has a configuration including an optical fiber communication path congestion detection unit 1150 instead of the wavelength slot fragmentation detection unit 1120 provided in the optical network control device 1101 according to the second embodiment. Other configurations are the same as the configuration of the optical network control apparatus 1101 according to the second embodiment, and thus description thereof is omitted.

  Next, the operation of the optical network control apparatus 1103 according to this embodiment will be described. FIG. 9 is a flowchart for explaining the operation of the optical network control apparatus 1103 according to this embodiment.

  In the optical network control apparatus 1103, the optical fiber communication path congestion detection unit 1150 monitors the usage status of the wavelength slots in the optical fiber communication path (step S411).

  When the optical fiber communication path congestion detection unit 1150 detects an opportunity to rearrange the optical path, the optical path rearrangement calculation unit 1130 performs an optical path rearrangement process. The optical fiber communication path congestion detection unit 1150 can be triggered when either the number of unused wavelength slots falls below a predetermined number or when the number of used wavelength slots exceeds a predetermined number. Here, when the optical fiber communication path congestion detection unit 1150 detects that the number of used wavelength slots of the optical fiber communication path exceeds the threshold (step S412), the optical path communication path ID is changed to the optical path rearrangement calculation unit. 1130 is notified (step S413). It is also possible to specify an optical fiber communication path in which the number of free wavelength slots falls below the threshold, or an optical fiber communication path in which the total number of free wavelength slots over a plurality of hops falls below the threshold.

  After receiving the notification from the optical fiber communication path congestion detection unit 1150, the optical path rearrangement calculation unit 1130 reads, from the optical path management DB 1113, an optical path that passes through the optical fiber communication path in which the congestion state occurs (step S414). . The alternative route search unit 1131 included in the optical path rearrangement calculation unit 1130 searches for the shortest route connecting the start point optical node and the end point optical node of the optical path as an alternative route (step S415).

  The variable wavelength slot arrangement calculation unit 1132 determines the required number of wavelength slots in the shortest path and the modulation method used at that time (step S416).

  The wavelength slot number reduction determination unit 1133 determines whether or not the required number of wavelength slots of the optical path increases by passing through the alternative path (step S417). If it is determined that the number of wavelength slots increases (step S417 / YES), the optical path setting is not changed.

  When the wavelength slot number reduction determination unit 1133 determines that the required number of wavelength slots decreases or does not change by passing through the alternative path (step S417 / NO), there is an available wavelength slot on the alternative path. If it exists (step S418 / YES), a wavelength path is assigned to an empty wavelength slot (step S419). If there is no available wavelength slot on the alternative path (step S418 / NO), the alternative path at this time is excluded from the path candidates (step S420).

  The optical path rearrangement calculation unit 1130 determines whether or not there is an unassigned traffic request (step S421). That is, it is determined whether or not there is an unprocessed optical path among the optical paths to be rearranged. When there is an unprocessed optical path (step S421 / YES), the optical path rearrangement calculation unit 1130 repeats the processing from step S414 to step S420.

  The above-described processing is executed for all optical paths that pass through the optical fiber communication path in which the congestion state occurs. When there is no unprocessed optical path (step S421 / NO), the optical path placement control unit 1140 notifies each optical node device of the optical path reset result (step S422), and the process ends. .

  Note that if an available wavelength slot is not found in the shortest path, the alternative path search unit 1131 may search for the kth shortest path using, for example, a kth shortest path search algorithm.

  The optical network control apparatus 1102 according to the third embodiment may further include a rearrangement optical path management DB 1114 and an optical path rearrangement order calculation unit 1134 to rearrange the wavelength allocation order of the optical paths.

  The optical path arrangement control unit 1140 notifies the wavelength setting control unit 1211 included in the optical node devices 1201 to 1205 included in the optical network 1300 of the wavelength slot number of the optical path to be reset. Further, the route setting control unit 1214 is notified of the route setting information of the large-grain variable switching device 1213 regarding the alternative route. Based on the notification, the wavelength setting control unit 1211 controls the center frequency and modulation method of the signal light transmitted from the variable optical transponder 1212, and controls the setting of the wavelength slot that passes through the large-grain variable switching device 1213. On the other hand, the route setting control unit 1214 changes the optical fiber communication path connected to the variable optical transponder 1212 from the optical fiber communication path 1301 used for the current path to the optical fiber communication path 1302 used for the alternative path. The large grain size variable switching device 1213 is controlled. Thereby, it can switch to an alternative path | route.

  By the operation of the optical network control apparatus 1103 according to the present embodiment described above, it is possible to efficiently eliminate the congestion state in the optical fiber communication path. Furthermore, since the wavelength slot number reduction determination unit 1133 is configured to exclude the optical path in which the number of wavelength slots increases from the object of reoptimization, it is possible to reduce the work time and work man-hours. That is, it is possible to improve the network usage efficiency at high speed without impairing the reliability of the network.

  As described above, according to the optical network control apparatus 1103 and the optical communication system of the present embodiment, even when the elastic optical network method is used, the optical path is rearranged without increasing the number of processing steps. Thus, the frequency utilization efficiency can be improved.

  In each of the embodiments described above, detection of wavelength fragmentation or detection of a congestion state in an optical fiber communication path is triggered, but the present invention is not limited to this. For example, when newly establishing communication between bases in an optical communication system, the re-optimization process may be executed in response to the occurrence of a new optical path setting request (interrupt request). Specifically, in setting a new optical path, there are limitations on the number of wavelength slots in the optical fiber communication path, and the number of wavelength slots for new communication may be insufficient. At this time, according to the optical network control device of each of the above-described embodiments, wavelength resources can be re-optimized for the existing operational optical path, so that assignable wavelength slots can be created. become.

  The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the invention described in the claims, and it is also included within the scope of the present invention. Not too long.

100, 1100, 1101, 1102, 1103 Optical network control device 110 Relocation optical path extraction means 111 Alternative path search means 112 Wavelength slot allocation calculation means 113 Wavelength slot number determination means 120 Optical path relocation means 121 Optical path reassignment means 122 Optical path arrangement control means 1000 Optical communication system 1110 Database unit 1111 Request traffic DB
1112 Network equipment DB
1113 Optical path management DB
1114 Rearrangement optical path management DB
DESCRIPTION OF SYMBOLS 1120 Wavelength slot fragmentation detection part 1130 Optical path rearrangement calculation part 1131 Alternative path search part 1132 Variable wavelength slot arrangement | positioning calculation part 1133 Wavelength slot number reduction determination part 1134 Optical path rearrangement order calculation part 1140 Optical path arrangement | positioning control part 1150 Optical fiber Communication path congestion detection unit 1201, 1202, 1203, 1204, 1205 optical node device 1211 wavelength setting control unit 1212 variable optical transponder 1213 large granularity variable switching device 1214 route setting control unit 1300 optical network

Claims (17)

Relocation optical path extraction that extracts the relocation target optical path to be relocated from the existing optical paths that are existing optical paths in the optical network based on the attributes of the relocation optical path when relocation is performed. Means,
An optical network control device comprising: an optical path rearrangement unit that executes rearrangement processing on the rearrangement target optical path. The optical network control device according to claim 1, wherein a physical path of the rearranged optical path is different from a physical path of the existing optical path. The attribute of the rearrangement optical path is the number of wavelength slots to which the rearrangement optical path is allocated,
The rearrangement optical path extraction means reallocates the existing optical path when the rearrangement optical path can be allocated to a number of wavelength slots smaller than the number of wavelength slots to which the existing optical path is allocated. The optical network control device according to claim 1, wherein the optical network control device is extracted as an arrangement target optical path. The rearrangement optical path extraction means includes an alternative path search means, a wavelength slot arrangement calculation means, and a wavelength slot number determination means,
The optical path relocation means comprises an optical path reallocation means and an optical path allocation control means,
The alternative route search means searches for an alternative route that is a physical route different from the physical route of the existing optical path,
The wavelength slot arrangement calculating means calculates an arrangement of alternative wavelength slots that are wavelength slots available in the alternative path,
The wavelength slot number determination means determines whether the rearranged optical path can be allocated to a number of the alternative wavelength slots smaller than the number of wavelength slots to which the existing optical path is allocated,
When the wavelength slot number determination unit determines that the relocation optical path can be allocated, the optical path reassignment unit sets the existing optical path as the relocation target optical path, and sets the relocation target optical path as Assign to said alternative wavelength slot;
The optical network according to any one of claims 1 to 3, wherein the optical path arrangement control unit notifies the optical node device configuring the optical network of information related to the rearrangement target optical path and the alternative wavelength slot. Control device. Relocation detection means for monitoring the usage status of the wavelength slots in the optical fiber communication path constituting the optical network and detecting an opportunity to relocate the existing optical path;
The rearrangement detection means sends a detection notification to the rearrangement optical path extraction means when the trigger is detected,
The optical network control device according to any one of claims 1 to 4, wherein the rearrangement optical path extraction unit performs a process of extracting the rearrangement target optical path when the detection notification is received. The rearrangement detection means is triggered by any of the following: when wavelength fragmentation occurs, when the number of unused wavelength slots falls below a predetermined number, and when the number of used wavelength slots exceeds a predetermined number The optical network control device according to claim 5. Relocation optical path storage means for storing information on a plurality of relocation target optical paths;
A rearrangement order determining means for determining an order of executing the rearrangement process for the plurality of rearrangement target optical paths based on attributes of the rearrangement target optical paths;
Further comprising
The optical network control device according to any one of claims 1 to 6, wherein the optical path relocation unit executes the relocation processing based on the order. The attribute of the relocation target optical path is one of the number of wavelength slots to which the relocation target optical path is allocated, the physical path length of the relocation target optical path, and the number of hops of the relocation target optical path. The optical network control device according to claim 7. An optical network control device according to any one of claims 1 to 8 and an optical node device,
The optical node device is:
A variable optical transponder capable of varying the center frequency and modulation method of the transmitted signal light and the slot width of the optical path;
A large-grain variable switching device connected to an optical fiber communication path constituting the optical network and changing an input / output path in units of optical paths;
An optical node that receives optical path rearrangement information including information related to the rearrangement target optical path from the optical path rearrangement unit, and controls the variable optical transponder and the large-grain variable switching device based on the optical path rearrangement information An optical communication system comprising: control means. From the existing optical path that is an existing optical path in the optical network, the rearrangement target optical path to be rearranged is extracted based on the attribute of the rearrangement optical path when rearranged.
An optical path setting method for executing rearrangement processing on the rearrangement target optical path. The optical path setting method according to claim 10, wherein a physical path of the rearranged optical path is different from a physical path of the existing optical path. The attribute of the rearrangement optical path is the number of wavelength slots to which the rearrangement optical path is allocated,
The existing optical path is extracted as the rearrangement target optical path when the rearrangement optical path can be allocated to a smaller number of wavelength slots than the number of wavelength slots to which the existing optical path is allocated. 10. The optical path setting method described in 10 or 11. When extracting the rearrangement target optical path,
Search for an alternative route that is a physical route different from the physical route of the existing optical path,
Calculating an arrangement of alternative wavelength slots that are available in the alternative path;
Determining whether the rearranged optical path can be allocated to a number of the alternative wavelength slots smaller than the number of wavelength slots to which the existing optical path is allocated;
When performing the rearrangement process for the rearrangement target optical path,
When it is determined that the rearranged optical path can be assigned, the existing optical path is used as the rearrangement target optical path, and the rearrangement target optical path is assigned to the alternative wavelength slot;
The optical path setting method according to any one of claims 10 to 12, wherein information on the relocation target optical path and the alternative wavelength slot is notified to an optical node device configuring the optical network. Monitoring the use status of the wavelength slots in the optical fiber communication path constituting the optical network, and further detecting a trigger for rearranging the existing optical path;
The optical path setting method according to claim 10, wherein when the trigger is detected, a process of extracting the rearrangement target optical path is performed. When detecting an opportunity to rearrange the existing optical path,
The optical system according to claim 14, wherein wavelength triggering occurs, the number of unused wavelength slots falls below a predetermined number, or the number of used wavelength slots exceeds a predetermined number. Path setting method. Storing information on a plurality of relocation target optical paths;
Determining the order in which the rearrangement processing is performed for the plurality of rearrangement target optical paths based on attributes of the rearrangement target optical paths;
The optical path setting method according to any one of claims 10 to 15, wherein the rearrangement process is executed based on the order. The attribute of the relocation target optical path is one of the number of wavelength slots to which the relocation target optical path is allocated, the physical path length of the relocation target optical path, and the number of hops of the relocation target optical path. The optical path setting method according to claim 16.

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