JP6514092B2 - Network management device, recovery procedure determination method and program - Google Patents

Description

  The present invention relates to a network management device, recovery procedure determination method and program.

  When a large-scale disaster occurs over a wide area, communication disconnection due to the disconnection of an optical fiber connecting between a node and a communication device occurs over the wide area. As a method for maintaining communication even when such a disaster occurs, protection schemes and restoration schemes for wavelength paths and sub λ paths have been studied (Non-Patent Document 1). If a lot of cutting of the optical fiber occurs so that protection or restoration can not be performed, it is necessary for a worker to rush to the site where the cutting of the optical fiber has occurred to repair or replace the optical fiber.

Yining Cao, Yabin Ye, Hongyi Xie, Xiaoping Zheng, Yanhe Li, Hanyi Zhang, "Collision avoidance wavelength assignment scheme for distributed path restoration in optical networks," Photonic Network Communications, April 2010, Volume 19, Issue 2, p. 155- 160

  However, since the number of workers who can repair or replace the optical fibers connecting between the communication devices is limited, when communication disconnection due to the cutting of the optical fibers occurs in a wide area, the workers rushing to the site are not enough. There is a problem that it takes time to restore communication. Such a problem similarly exists in a transmission line using a transmission medium other than an optical fiber.

  In view of the above-described circumstances, the present invention provides a network management apparatus, recovery procedure determination method, and program capable of reducing the time required for communication recovery when communication disconnection occurs in a wide area due to a failure in a transmission path connecting communication devices. The purpose is to provide.

  One aspect of the present invention is a network management apparatus in a communication network including a plurality of communication devices, a plurality of transmission paths connecting the communication devices, and a network management device, wherein the plurality of communication devices and the plurality of transmissions A network information storage unit storing network information including physical topology information indicating connection with a path, and paths of paths provided between the communication devices and path information indicating presence or absence of a fault; communication in the communication network An update unit that updates the network information in response to a notification of occurrence of disconnection; and a recovery procedure calculation unit that calculates an order of recovering the transmission path in which the communication disconnection has occurred based on the network information; The recovery procedure calculation unit is configured to recover the transmission paths in the descending order of the number of the accommodated paths among the transmission paths in which the communication disconnection occurred. Determining a network management device.

  Further, according to one aspect of the present invention, in the above-described network management device, the recovery procedure calculation unit sets, as a variable, the number of transmission paths to be recovered before communication becomes possible on all paths where communication disconnection occurs. Using mathematical programming with an objective function that is a function and whose value obtained as the variable increases becomes an objective function, the order of recovering the transmission path in which the communication interruption has occurred is calculated.

  Further, according to one aspect of the present invention, in the above-described network management device, the recovery procedure calculation unit searches a path between the communication devices having the highest priority among the communication devices in which the communication interruption has occurred, The transmission paths which are obtained by searching are determined to be recovery targets in order from the transmission path having the largest number of paths accommodated by the transmission path, and the priority assigned between the communication devices, among the communication devices The priority between the communication devices is determined by combining one or more of the traffic volume and the number of paths provided between the communication devices.

  Further, according to one aspect of the present invention, in the above-described network management device, the restoration procedure calculation unit calculates the number of connections, which is the number of the transmission paths connected to each of the communication devices, and the adjacent communication devices The transmission paths between communication devices having a large total value of the number of connections are determined as recovery targets in order.

  Further, according to one aspect of the present invention, in the network management device, the restoration procedure calculation unit calculates a shortest path or a shortest spanning tree between the communication devices in the optical communication network, and the shortest path or the smallest path. The transmission paths included in the spanning tree are determined as recovery targets in preference to the transmission paths not included in the shortest path or the minimum spanning tree.

  Further, according to one aspect of the present invention, in the above-described network management apparatus, the recovery procedure calculation unit is a transmission path including a large number of paths to be accommodated in a state before the communication interruption occurs among the transmission paths where the communication interruption occurs. Decide for recovery in order from.

  Further, according to one aspect of the present invention, there is provided physical topology information indicating connection between a plurality of communication devices, a plurality of transmission paths connecting the communication devices, a plurality of the communication devices and the plurality of transmission paths, And a network management apparatus comprising a network information storage unit storing network information including paths of respective paths provided between the communication apparatuses and path information indicating presence or absence of a failure; a recovery procedure performed by the network management apparatus in the communication network It is a determination method, comprising: an updating step of updating the network information in response to a notification of occurrence of communication disconnection in the communication network; and calculating an order of recovering the transmission path in which the communication disconnection has occurred based on the network information. A recovery procedure calculating step, and in the recovery procedure calculating step, the transmission path in which the communication interruption occurred Among them, the number of accommodated to that path is determined from a larger transmission path in the recovery target sequentially, a recovery procedure determination method.

  Moreover, one aspect of the present invention is a program for causing a computer to function as the above-described network management device.

  According to the present invention, it is possible to reduce the time required for communication recovery when communication disconnection occurs in a wide area due to a failure in a transmission path connecting between communication devices.

FIG. 1 is a block diagram showing a configuration example of a network management device in a first embodiment. 6 is a flowchart showing processing of calculating a recovery procedure by the network management device in the first embodiment. 5 is a flowchart showing a process of calculating a restoration procedure including restoration of a physical link in the first embodiment. A first flowchart showing a process of calculating a restoration procedure including restoration of a physical link by the network management apparatus in the second embodiment. The 2nd flow chart which shows the processing in which the network management device in a 2nd embodiment computes the restoration procedure including restoration of a physical link. The flowchart which shows the process which the network management apparatus in 3rd Embodiment calculates the restoration procedure including the restoration of a physical link. The flowchart which shows the process which the network management apparatus in 4th Embodiment calculates the restoration procedure including restoration of a physical link. The flowchart which shows the process which the network management apparatus in 5th Embodiment calculates the restoration procedure including the restoration of a physical link. The flowchart which shows the process which the network management apparatus in 6th Embodiment calculates the restoration procedure including restoration of a physical link.

  Hereinafter, a network management apparatus, a recovery procedure determination method and a program according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, components given the same reference numerals perform similar operations, and redundant description will be omitted as appropriate.

  The network management apparatus in the embodiment described below has a procedure for restoring communication when a large-scale disaster occurs over a wide area and an optical fiber disconnection occurs so that path protection and restoration can not be performed. decide. By using the network management device, it is possible to reduce the time required for recovery from communication failure over a wide area.

The “sub λ path” in this specification is described in ODU (Optical channel Data Unit) described in Reference 1, SDH (Synchronous Digital Hierarchy) described in Reference 2, and Reference 3 It is a communication path that can perform switching and multiplexing / demultiplexing by performing electrical processing such as MPLS-TP (Multiprotocol Label Switching Transport Profile). Further, the “wavelength path” in the present specification is a communication path which enables switching without changing the light / electricity conversion / electricity / light conversion as it is and does not perform wavelength conversion at the relay node.
[Reference 1] “7. Multiplexing / mapping principles and bit rates,” Recommendation ITU-T G.709 / Y.1331, February 2012
[Reference 2] "6 Basic multiplexing principles," ITU-T Recommendation G.707 / Y.1322, January 2007
[Reference 3] "2. MPLS-TP Packet Encapsulation and Forwarding", IETF RFC 5960, August 2010

First Embodiment
FIG. 1 is a block diagram showing a configuration example of the network management device 1 in the first embodiment. The network management device 1 is provided in an optical communication network. The optical communication network includes a plurality of communication devices (nodes) and a plurality of optical fibers as transmission paths connecting the communication devices. The network management device 1 includes a receiving unit 11, an updating unit 12, a network information storage unit 13, a recovery procedure calculation unit 14, a recovery procedure storage unit 15, and a recovery procedure output unit 16. The receiving unit 11 receives a notification of occurrence of communication disconnection in the optical communication network managed by the network management device 1. The notification of the occurrence of the communication disconnection includes information indicating the communication path of the wavelength path or sub λ path in which the communication disconnection has occurred, and information indicating the start point and the end point of the communication path in which the communication disconnection has occurred. Notification of occurrence of communication disconnection is transmitted from the network monitoring device monitoring the connection status of communication in the optical communication network to the network management device 1.

  The updating unit 12 updates the network information stored in the network information storage unit 13 based on the notification of the occurrence of the communication disconnection received by the receiving unit 11. The network information includes physical topology information, failure information, wavelength path information, free wavelength information, and sub λ path information. The physical topology information is information indicating the physical topology of the communication system monitored by the network monitoring device, and is information indicating the connection between the plurality of communication devices and the plurality of optical fibers. The failure information is information indicating the failed node and the cut optical fiber. The wavelength path information is information indicating the path and wavelength of each of the existing wavelength paths provided in each optical fiber, and the wavelength path in which the communication interruption has occurred. The free wavelength information is information indicating a free wavelength in the optical fiber. The sub λ path information is information existing for each sub λ path, and the wavelength path in which the sub λ path is accommodated, the granularity of the sub λ path, the priority of the sub λ path, and the presence or absence of occurrence of communication disconnection And information indicating Here, the wavelength of the existing wavelength path provided in the optical fiber is shown as a frequency or a wavelength number when the wavelength grid is fixed, and is shown as a center frequency and a frequency width when the wavelength grid is not fixed.

  The update unit 12 updates the failure information, the wavelength path information, and the sub λ path information based on the notification of the occurrence of the communication disconnection. When the operation of the optical communication network is started, the network information storage unit 13 stores the latest network information. Further, the update unit 12 receives, through the reception unit 11, notification of assignment of a new sub λ path, deletion of a sub λ path, and change of physical topology, in addition to notification of occurrence of communication disconnection. When the update unit 12 receives these notifications, it updates the network information based on the received notifications.

  When the reception unit 11 receives the notification of the occurrence of the communication disconnection, the recovery procedure calculation unit 14 calculates the recovery procedure in the optical communication network based on the network information updated by the update unit 12. The recovery procedure calculation unit 14 stores the calculated recovery procedure in the recovery procedure storage unit 15. The recovery procedure storage unit 15 is a storage device that stores the recovery procedure calculated by the recovery procedure calculation unit 14. The recovery procedure storage unit 15 is configured using, for example, a main storage device such as a memory, and a non-volatile non-temporary storage medium such as a hard disk or a flash memory. The recovery procedure output unit 16 outputs the recovery procedure stored in the recovery procedure storage unit 15 to the outside of the network management device 1. The recovery procedure output unit 16 includes, for example, a display device such as a display, and displays characters, graphics, and the like indicating the recovery procedure to notify the administrator of the communication system of the recovery procedure. Further, the recovery procedure output unit 16 may transmit recovery information indicating the recovery procedure to another device or system.

  FIG. 2 is a flowchart showing processing of the network management device 1 according to the first embodiment to calculate a recovery procedure. When the calculation of the restoration procedure is started in the network management device 1, the restoration procedure calculation unit 14 reads out network information from the network information storage unit 13 (step S101). The restoration procedure calculation unit 14 detects a wavelength path in which no communication interruption has occurred among the wavelength paths provided between the start and end nodes of each sub λ path in which the communication interruption has occurred. The restoration procedure calculation unit 14 performs accommodation design in which the sub λ path in which the communication interruption has occurred is allocated to the detected wavelength path (step S102). That is, a sub λ path that enables communication between the start point node and the end point node of the sub λ path where the communication interruption has occurred is newly provided in the communicable wavelength path.

  The restoration procedure calculation unit 14 determines whether or not all the sub λ paths in which the communication interruption has occurred can be accommodated in the wavelength path in which the communication interruption has not occurred by the accommodation design in step S102 (step S103). If it can be accommodated (step S103: YES), the restoration procedure calculation unit 14 stores the accommodation design in which each sub λ path for which the communication interruption has occurred is allocated to the communicable wavelength path in the restoration procedure storage unit 15 as a restoration procedure. (Step S104) The process proceeds to step S105.

  If it can not be accommodated in the determination of step S103 (step S103: NO), the restoration procedure calculation unit 14 allocates between the start and end nodes of each sub λ path that can not be allocated to the communicable wavelength path. The accommodation design is performed in which the wavelength path for accommodating the sub λ path which could not be transmitted is allocated to the optical fiber in which the communication interruption has not occurred (step S111). The restoration procedure calculation unit 14 determines whether the wavelength path can be accommodated in the optical fiber (step S112).

  If the wavelength path can be accommodated in the optical fiber (step S112: YES), the recovery procedure calculation unit 14 generates a communication break in the communicable wavelength path including the wavelength path accommodated in the optical fiber in step S111. The accommodation design which allocates a path is performed (step S113). The restoration procedure calculation unit 14 uses the accommodation design in which the wavelength path is allocated to the optical fiber and the accommodation design in which each sub λ path in which the communication interruption occurred is allocated to the communicable wavelength path to the restoration procedure storage unit 15. It is stored (step S114), and the process proceeds to step S105.

  If it is determined in step S112 that the wavelength path can not be accommodated in the optical fiber (step S112: NO), the restoration procedure calculation unit 14 calculates restoration of all layers (step S121). That is, the restoration procedure calculation unit 14 calculates the order of restoring the optical fiber and the wavelength path, and the accommodation design of the wavelength path and the sub λ path. The restoration procedure calculation unit 14 stores the calculation result as the restoration procedure in the restoration procedure storage unit 15 (step S122), and advances the process to step S105.

  The recovery procedure output unit 16 outputs the recovery procedure stored in the recovery procedure storage unit 15 (step S105), and ends the process of calculating the recovery procedure.

The necessary number of wavelength paths in the process of step S111 is determined by rounding up the value obtained by dividing the physical band value of the wavelength path by the total value of the band values of the same sub λ path by the start and end point nodes. Further, for example, an algorithm of path search with depth priority and an algorithm of path search with breadth priority are used as an algorithm used in accommodation design for assigning wavelength paths to optical fibers. The wavelength assignment algorithm uses, for example, the First Fit algorithm assigned from a small number described in reference 4. The accommodation design of the wavelength path described below is performed in the same procedure.
[Reference 4] Hui Zang, Jason P. Jue, Biswanath Mukherjee, "A review of routing and wavelength assignment approaches for wavelength-routed optical WDM networks," Optical Networks Magazine, January 2000, Volume 1, Number 1, p. 47 -60

  The process in step S121 where a physical link (optical fiber) recovery procedure is required will be described in more detail. FIG. 3 is a flowchart showing a process of calculating a restoration procedure including restoration of a physical link in the first embodiment. The restoration procedure calculation unit 14 uses mathematical programming to calculate the order of restoring the optical fiber and the wavelength path (S201). Since wavelength assignment is not performed in mathematical programming, the restoration procedure calculation unit 14 performs wavelength assignment and accommodation design of a wavelength path using a wavelength assignment algorithm between the start point and end point nodes for recovering the wavelength path (see Step S202). The restoration procedure calculation unit 14 performs accommodation design in which the sub λ path in which the communication interruption has occurred is allocated to the wavelength path to be restored and the communicable wavelength path (step S203), and ends the process of step S121.

The mathematical programming in step S201 can be expressed, for example, by the following formulas (1) to (7).

In the equations (1) to (7), t∈T indicates the order of recovering the optical fiber in the communication system. e (i, j) ∈E indicates a physical link (optical fiber) connecting node (i) and node (j) in the communication system. d (s, d) ∈ D indicates a pair of start point node (s) and end point node (d) of the sub λ path. N _{d (s, d)} indicates the number of sub λ paths in the pair d (s, d) of the start point node (s) and the end point node (d). N _UP indicates the upper limit value of the number of sub λ paths that can be accommodated in the physical link e (i, j) in the restoration order. N _ML indicates the upper limit value of the sub λ path that can be accommodated in the physical link e (i, j).

Further, each of variables n _{d (s, d), t 1} , x _{t, e (i, j)} and p _{e (i, j) t} ^{d (s, d)} in the formulas (1) to (7) is Possible values are expressed by equation (8).

Next, each of Formula (1)-Formula (7) is demonstrated.
Equation (1) is an objective function, and indicates the minimization of the time required to restore the wavelength path.
Equation (2) is a constraint for determining the path of the sub λ path.
Equation (3) is a constraint indicating the total value of wavelength paths between nodes.
Expression (4) is a constraint that allows accommodation of the sub λ path of the section when the physical link e (i, j) is restored.
Expression (5) is a constraint on the upper limit value of the number of wavelength paths that can be accommodated when the physical link e (i, j) is restored.
Expression (6) is a constraint for not deleting the restored physical link e (i, j) at the next restoration.
Expression (7) is a constraint that allows only one physical link to be recovered in one recovery.
In addition, Formula (2) is given by a well-known technique like the flow storage formula of reference 5, for example.
[Reference 5] Keyao Zhu, Biswanath Mukherjee, "Traffic Grooming in an Optical WDM Mesh Network," IEEE Journal on selected areas in communications, January 2002, Volume 20, Issue 1, p. 122-133

From the mathematical programming performed in step S201, x _{t, e (i, j)} and p _{e (i, j) t} ^{d (s, d)} are calculated, and physical links (optical fibers) and wavelength paths are calculated. The order of recovery is obtained. In the first embodiment, a solution satisfying the objective function (minimization of the recovery time of the total wavelength path) using mathematical programming when the sub λ path where the communication interruption has occurred can not be accommodated in the communicable wavelength path. The recovery procedure can be calculated by asking for The objective function is a function having, as a variable, the number of physical links (optical fibers) to be restored before communication becomes possible in all wavelength paths in which the communication interruption occurred, as shown in equation (1). It is a function whose value obtained increases with the increase. By restoring the fiber link consisting of the optical fiber and the communication device according to the calculated restoration procedure and accommodating the wavelength path and the sub λ path, communication interruption due to the failure of the optical fiber connecting between the communication devices occurred in a wide area In this case, the time required for communication recovery can be reduced.

  In the first embodiment, the process of calculating the restoration procedure in consideration of the restoration of both the wavelength path and the sub λ path has been described. However, a recovery procedure not considering the sub λ path may be calculated. That is, steps S102, S103, S104, S111, and S113 in the process shown in FIG. 2 and step S203 in the process shown in FIG. 3 may be omitted. In this case, in step S112, it is determined whether or not all the required number of wavelength paths can be accommodated in the communicable optical fiber, and if all the wavelength paths can be accommodated, the accommodation design is restored to the procedure storage unit The processing is ended by storing the restoration procedure as the restoration procedure 15 and when all the wavelength paths can not be accommodated, the process proceeds to step S121. In step S201, the order of recovering the optical fiber and wavelength path is calculated using mathematical programming, and in step S203, wavelength allocation is performed, and the process is ended.

Second Embodiment
The configuration of the network management device in the second embodiment is the same as the configuration of the network management device 1 in the first embodiment shown in FIG. Further, the process of the network management apparatus in the second embodiment for calculating the restoration procedure is substantially the same as the process shown in FIG. 2, but the process in step S121 is different. Here, the description of the configuration of the network management apparatus is omitted, and step S121 which is different from the first embodiment in the process of calculating the restoration procedure will be described.

  FIG. 4 is a flowchart showing a process (step S121) in which the network management apparatus in the second embodiment calculates a restoration procedure including restoration of physical links. The recovery procedure calculation unit 14 calculates a total value of the number of sub λ paths not included in the recovery target among the sub λ paths in which the communication disconnection has occurred between the start and end nodes (step S301). When the process of step S121 is started, the recovery target is empty (null). The restoration procedure calculation unit 14 executes path search in the optical communication network using the k-shortest path algorithm between the start and end nodes with the highest priority among the start and end nodes not included in the recovery target ( Step S302).

  The restoration procedure calculation unit 14 is a sub λ path in which a communication interruption has occurred among the sub λ paths accommodated for each physical link existing on the route calculated in step S 302 and is not included in the recovery target The total value of the number of sub λ passes is calculated (step S303). The restoration procedure calculation unit 14 is the physical link existing in the route calculated in step S302 and among the physical links not included in the restoration target, the total value of the number of accommodated sub λ paths is the largest. The physical link is added to the recovery target (step S304).

  The restoration procedure calculation unit 14 can perform accommodation design in which the wavelength path between the start point and end point nodes targeted for the route search in step S302 can be allocated to the fiber network including the communicable physical links and the physical links to be restored. It is determined whether or not (step S305). When the wavelength path can not be accommodated (step S305: NO), the restoration procedure calculation unit 14 returns the process to step S304.

  If all the wavelength paths can be accommodated (step S305: YES), the recovery procedure calculation unit 14 becomes a target of route search in step S302 for the fiber network consisting of communicable physical links and physical links to be recovered. The accommodation design is performed to allocate the wavelength path between the start and end nodes, and the accommodation design is performed to allocate all the sub λ paths between the start and end nodes targeted for the route search to the wavelength path in step S302 (step S306). The restoration procedure calculation unit 14 determines whether or not accommodation design is possible in which all sub λ paths between the start and end point nodes targeted for the route search in step S302 can be allocated to wavelength paths (step S307). When all sub λ paths can not be accommodated (step S307: NO), the recovery procedure calculation unit 14 returns the process to step S304.

  If all the sub λ paths can be accommodated (step S307: YES), the recovery procedure calculation unit 14 determines the wavelengths accommodated in the physical links that are communicable or recoverable with respect to all the sub λ paths in which the communication interruption occurred. It is determined whether the storage design to be assigned to the path is completed (step S308). If the storage design has not been completed (step S308: NO), the recovery procedure calculation unit 14 returns the process to step S301. When accommodation design is completed (Step S308: YES), restoration procedure calculation part 14 ends processing of Step S121. The restoration procedure calculated in each process of step S121 is output to the outside in step S105 of FIG.

  Here, the calculation result stored in the restoration procedure storage unit 15 as the restoration procedure includes the physical link to be restored, the restoration order thereof, and the accommodation design of the wavelength path and the sub λ path. The order of recovery may be the order in which the physical links are added to the recovery target, or may be the order in which the movement distance when recovering the physical link and the communication device to be recovered is the shortest.

  In the method of calculating the total value of the number of sub λ paths not included in the recovery target among the sub λ paths in which the communication interruption occurred in step S301 and step S303, the start and end nodes of the sub λ path on the route Even if the pair is included, it is counted. Also, instead of the total value of the number of sub λ paths, the total traffic volume on the physical link or the total value of the priority evaluation values may be used. Here, the priority evaluation value is, for example, a numerical value representing the priority assigned in advance for each sub λ path or wavelength path, or the degree of influence of the communication disconnection. The higher the priority, the higher the priority evaluation value is assigned.

  "Priority" used in step S302 may be determined using either (1) priority evaluation value, (2) total traffic volume, or (3) number of sub λ paths, or two Or you may determine combining three. For example, in the case of determining the priority in the order of the priority evaluation value, the total traffic volume, and the number of sub λ paths, when there are a plurality of pairs of start and end nodes having the same priority evaluation value, the total traffic volume is evaluated When the total traffic volume is the same, the number of sub λ paths is evaluated to determine the final priority.

  In the second embodiment, the process of calculating the restoration procedure in consideration of the restoration of both the wavelength path and the sub λ path has been described. However, a recovery procedure not considering the sub λ path may be calculated. That is, steps S102, S103, S104, S111, and S113 in the process shown in FIG. 2 may be omitted. In this case, in step S112, it is determined whether or not all the required number of wavelength paths can be accommodated in the communicable optical fiber, and if all the wavelength paths can be accommodated, the accommodation design is restored to the procedure storage unit The processing is ended by storing the restoration procedure as the restoration procedure 15 and when all the wavelength paths can not be accommodated, the process proceeds to step S121. The process of step S121 in this case will be described below. FIG. 5 is a flowchart showing a process (step S121 in which the sub λ path is not considered) in which the network management apparatus according to the second embodiment calculates a restoration procedure including restoration of physical links.

The restoration procedure calculation unit 14 calculates a total value of the number of wavelength paths not included in the restoration target among the wavelength paths in which the communication interruption has occurred between the start point and end point nodes (step S351). The restoration procedure calculation unit 14 executes path search in the optical communication network using the k-shortest path algorithm between the start and end nodes with the highest priority among the start and end nodes not included in the recovery target ( Step S352).

  The restoration procedure calculation unit 14 is, for each physical link existing on the route calculated in step S352, a wavelength path among the contained wavelength paths in which a communication interruption has occurred and which is not included in the restoration target The total value of the number of paths is calculated (step S353). Among the physical links existing in the route calculated in step S352 and not included in the recovery target, the recovery procedure calculation unit 14 recovers the physical link having the largest total value calculated in step S353. (Step S354).

  The restoration procedure calculation unit 14 can perform accommodation design in which the wavelength path between the start point and end point nodes targeted for the route search in step S352 can be allocated to the fiber network composed of the communicable physical links and the physical links to be restored. It is determined whether or not (step S355). If the wavelength path can not be accommodated (step S355: NO), the recovery procedure calculation unit 14 returns the process to step S354. When the wavelength path can be accommodated (step S355: YES), the recovery procedure calculation unit 14 is the target of the route search in step S352 for the fiber network composed of the communicable physical links and the recovery target physical links. A storage design is performed to allocate wavelength paths between start and end nodes (step S356).

  The restoration procedure calculation unit 14 determines whether or not all the wavelength paths in which the communication disconnection has occurred are assigned to the fiber network composed of the communicable physical links and the physical links to be recovered (step S357), If there is a wavelength path that has not been received (step S357: NO), the process returns to step S351. If all the wavelength paths have been allocated (step S 357: YES), the process of step S 121 ends. Here, the calculation result stored in the restoration procedure storage unit 15 as the restoration procedure includes the physical link to be restored, the restoration order thereof, and the accommodation design of the wavelength path.

  In the second embodiment, a recovery procedure is calculated by sequentially adding a recovery target to a recovery target in order from the fiber link including the optical fiber having many wavelength paths or sub λ paths to be accommodated and the communication device. By restoring the fiber link consisting of the optical fiber and the communication device according to the calculated restoration procedure and accommodating the wavelength path and the sub λ path, communication interruption due to the failure of the optical fiber connecting between the communication devices occurred in a wide area In this case, the time required for communication recovery can be reduced.

Third Embodiment
The configuration of the network management device in the third embodiment is the same as the configuration of the network management device 1 in the first embodiment shown in FIG. Further, the process of the network management apparatus in the third embodiment calculating the restoration procedure is substantially the same as the process shown in FIG. 2, but the process in step S121 is different. Here, the description of the configuration of the network management apparatus is omitted, and step S121 which is different from the first embodiment in the process of calculating the restoration procedure will be described.

  FIG. 6 is a flowchart showing a process (step S121) in which the network management apparatus in the third embodiment calculates a restoration procedure including restoration of physical links. The restoration procedure calculation unit 14 calculates the number of degrees in each of the communication devices (nodes) in the optical communication network (step S401). Here, the Degree number is the number (the number of connections) of physical links connected to adjacent nodes in a node. The restoration procedure calculation unit 14 sets, as a restoration target, a physical link that connects nodes having the largest sum of the Degrees among the adjacent nodes among the physical links that are communication disconnections and are not included in the restoration target. Add (step S402).

  The restoration procedure calculation unit 14 performs accommodation design for allocating wavelength paths to a fiber network composed of communicable physical links and physical links to be restored, and then performs accommodation design for allocating sub λ paths for wavelength paths. Perform (step S403). The restoration procedure calculation unit 14 determines whether all the sub λ paths can be accommodated in the fiber network including the communicable physical links and the restoration target physical links (step S404). When it can not accommodate (step S404: NO), the recovery procedure calculation unit 14 returns the process to step S402. If it can be accommodated (step S404: YES), the recovery procedure calculation unit 14 ends the process of step S121. The restoration procedure calculated in each process of step S121 is output to the outside in step S105 of FIG.

  In the third embodiment, the processing for calculating the restoration procedure in consideration of the restoration of both the wavelength path and the sub λ path has been described. However, a recovery procedure not considering the sub λ path may be calculated. That is, steps S102, S103, S104, S111, and S113 in the process shown in FIG. 2 may be omitted. In this case, in step S112, it is determined whether or not all the required number of wavelength paths can be accommodated in the communicable optical fiber, and if all the wavelength paths can be accommodated, the accommodation design is restored to the procedure storage unit The processing is ended by storing the restoration procedure as the restoration procedure 15 and when all the wavelength paths can not be accommodated, the process proceeds to step S121. In this case, in the process of step S121, the operation of step S403 replaces the operation of performing accommodation design in which wavelength paths are allocated to a fiber network composed of communicable physical links and physical links to be restored. Also, the determination in step S404 replaces the determination as to whether or not the wavelength path can be accommodated in the fiber network composed of the communicable physical link and the physical link to be restored.

  In the third embodiment, the recovery procedure is calculated by adding to the recovery target in order from the physical link connecting the nodes having a large sum of the degree of Degree among the adjacent nodes. By recovering the fiber link composed of the optical fiber and the communication device according to the calculated recovery procedure, the fiber link where the paths are concentrated is preferentially recovered, and many wavelength paths and sub λ paths can be recovered. As a result, it is possible to reduce the time required for communication recovery when communication disconnection due to a failure of optical fibers connecting between communication devices occurs over a wide area.

Fourth Embodiment
The configuration of the network management device in the fourth embodiment is the same as the configuration of the network management device 1 in the first embodiment shown in FIG. Further, the process in which the network management apparatus in the fourth embodiment calculates the restoration procedure is substantially the same as the process shown in FIG. 2, but the process in step S121 is different. Here, the description of the configuration of the network management apparatus is omitted, and step S121 which is different from the first embodiment in the process of calculating the restoration procedure will be described. In the fourth embodiment, instead of updating the network information, the updating unit 12 creates new network information based on the notification of communication disconnection, stores the new network information in the network information storage unit 13, and performs communication. Network information on the optical communication network before the disconnection occurs is also left in the network information storage unit 13.

  FIG. 7 is a flowchart showing a process (step S121) in which the network management apparatus in the fourth embodiment calculates a restoration procedure including restoration of physical links. The recovery procedure calculation unit 14 is a physical link in which a communication break has occurred, and among the physical links not included in the recovery target, the physical link in which the number of wavelengths accommodated before the communication break occurs is the largest. It is added to the recovery target (step S501). The restoration procedure calculation unit 14 performs accommodation design in which the wavelength path in which the communication break occurs is allocated to the fiber network including the communicable physical link and the physical link to be restored, and further the sub λ path in which the communication break occurs. A storage design is performed to allocate to the wavelength path (step S502).

  The restoration procedure calculation unit 14 determines whether all sub λ paths can be accommodated (step S503). When it can not accommodate (step S503: NO), the restoration procedure calculation unit 14 returns the process to step S501. If it can be accommodated (step S503: YES), the recovery procedure calculation unit 14 ends the process of step S121. The restoration procedure calculated in each process of step S121 is output to the outside in step S105 of FIG.

  In the fourth embodiment, the process of calculating the restoration procedure in consideration of the restoration of both the wavelength path and the sub λ path has been described. However, a recovery procedure not considering the sub λ path may be calculated. That is, steps S102, S103, S104, S111, and S113 in the process shown in FIG. 2 may be omitted. In this case, in step S112, it is determined whether or not all the required number of wavelength paths can be accommodated in the communicable optical fiber, and if all the wavelength paths can be accommodated, the accommodation design is restored to the procedure storage unit The processing is ended by storing the restoration procedure as the restoration procedure 15 and when all the wavelength paths can not be accommodated, the process proceeds to step S121. In this case, in the process of step S121, the operation of step S502 replaces the accommodation design in which the wavelength path is allocated to the fiber network composed of the communicable physical link and the physical link to be restored. In addition, the determination in step S503 replaces the determination as to whether all wavelength paths can be accommodated.

  In the fourth embodiment, the recovery procedure is calculated by adding to the recovery target sequentially from the physical link with the largest number of wavelength paths accommodated in the optical communication network before the occurrence of the communication disconnection. By recovering the fiber link composed of the optical fiber and the communication device according to the calculated recovery procedure, the physical link in which the wavelength path is concentrated is preferentially recovered, and many wavelength paths and sub λ paths can be recovered. As a result, it is possible to reduce the time required for communication recovery when communication disconnection due to a failure of optical fibers connecting between communication devices occurs over a wide area.

Fifth Embodiment
The configuration of the network management device in the fifth embodiment is the same as the configuration of the network management device 1 in the first embodiment shown in FIG. Further, the process of the network management apparatus in the fifth embodiment for calculating the restoration procedure is substantially the same as the process shown in FIG. 2, but the process in step S121 is different. Here, the description of the configuration of the network management apparatus is omitted, and step S121 which is different from the first embodiment in the process of calculating the restoration procedure will be described.

  FIG. 8 is a flowchart showing a process (step S121) in which the network management apparatus in the fifth embodiment calculates a restoration procedure including restoration of physical links. The restoration procedure calculation unit 14 determines the minimum spanning tree for the optical communication network (step S601). The restoration procedure calculation unit 14 calculates the number of degrees in each of the communication devices (nodes) in the optical communication network, and calculates the total value of the number of degrees between adjacent nodes (step S602).

  In the physical links included in the minimum spanning tree, the restoration procedure calculation unit 14 sorts the physical links in which the communication interruption has occurred in the descending order of the total value of the Degree number between adjacent nodes (step S603). In the physical links not included in the minimum spanning tree, the recovery procedure calculation unit 14 sorts the physical links in which the communication interruption has occurred in the descending order of the total value of the degree of degree between adjacent nodes (step S604).

  The restoration procedure calculation unit 14 adds one physical link in which the communication interruption has occurred to the restoration target in accordance with the order sorted in step S603 and step S604 (step S605). The physical link of communication disconnection to be added to the recovery target is preferentially selected from the physical links included in the minimum spanning tree. The restoration procedure calculation unit 14 performs accommodation design in which the wavelength path in which the communication break occurs is allocated to the fiber network including the communicable physical link and the physical link to be restored, and further the sub λ path in which the communication break occurs. A storage design is performed to allocate to the wavelength path (step S606).

  The restoration procedure calculation unit 14 determines whether all sub λ paths can be accommodated (step S607). When it can not accommodate (step S607: NO), the restoration procedure calculation unit 14 returns the process to step S605. If it can be accommodated (step S607: YES), the recovery procedure calculation unit 14 ends the process of step S121. The restoration procedure calculated in each process of step S121 is output to the outside in step S105 of FIG.

Here, the minimum spanning tree determined by the restoration procedure calculation unit 14 in step S601 is the smallest graph among the subgraphs of the tree structure in which all the nodes are connected. For the calculation of the minimum spanning tree, for example, the Kruskal algorithm or prim algorithm described in reference 6 is used.
[Ref. 6] RL Graham, Pavol Hell, "On the History of the Minimum Spanning Tree Problem," IEEE Annals of the History of Computing, January 1985, Volume 7, Issue 1, p. 43-57

  In the fifth embodiment, the process of calculating the restoration procedure in consideration of the restoration of both the wavelength path and the sub λ path has been described. However, a recovery procedure not considering the sub λ path may be calculated. That is, steps S102, S103, S104, S111, and S113 in the process shown in FIG. 2 may be omitted. In this case, in step S112, it is determined whether or not all the required number of wavelength paths can be accommodated in the communicable optical fiber, and if all the wavelength paths can be accommodated, the accommodation design is restored to the procedure storage unit The processing is ended by storing the restoration procedure as the restoration procedure 15 and when all the wavelength paths can not be accommodated, the process proceeds to step S121. In this case, in the process of step S121, the operation of step S606 performs an accommodation design in which a wavelength path in which a communication break occurs is allocated to a fiber network including communicable physical links and physical links to be restored. replace. Also, the determination in step S 607 replaces the determination as to whether all wavelength paths in which the communication interruption has occurred can be accommodated.

  In the fifth embodiment, priority is given to the physical link included in the minimum spanning tree, and the recovery procedure is calculated by adding to the recovery target in order from the physical link connecting the nodes having a large total number of Degree between adjacent nodes. By recovering the fiber link composed of the optical fiber and the communication device according to the calculated recovery procedure, the fiber link where the paths are concentrated is preferentially recovered, and many wavelength paths and sub λ paths can be recovered. As a result, it is possible to reduce the time required for communication recovery when communication disconnection due to a failure of optical fibers connecting between communication devices occurs over a wide area.

Sixth Embodiment
The configuration of the network management device in the sixth embodiment is the same as the configuration of the network management device 1 in the first embodiment shown in FIG. Further, the process in which the network management apparatus in the sixth embodiment calculates the restoration procedure is substantially the same as the process shown in FIG. 2, but the process in step S121 is different. Here, the description of the configuration of the network management apparatus is omitted, and step S121 which is different from the first embodiment in the process of calculating the restoration procedure will be described.

  FIG. 9 is a flowchart showing processing (step S121) in which the network management apparatus according to the sixth embodiment calculates a restoration procedure including restoration of physical links. The restoration procedure calculation unit 14 performs the shortest path search between all the start and end nodes in the optical communication network, and the wavelength paths and subs accommodated in each physical link (optical fiber) included in the searched shortest path. The number of λ passes is calculated (step S701).

  The recovery procedure calculation unit 14 selects one physical link having the largest number of paths accommodated among the physical links which are communication failures and is not included in the recovery target, and the selected physical link Is added to the recovery target (step S702). Here, the physical link to be restored may select the physical link having the largest number of accommodated wavelength paths, or select the physical link having the largest number of contained sub-λ paths. Alternatively, a physical link having the largest sum of the number of wavelength paths accommodated and the number of sub λ paths or the sum of predetermined weighting may be selected.

  The restoration procedure calculation unit 14 performs accommodation design in which the wavelength path in which the communication interruption has occurred is allocated to the fiber network including the communicable physical link and the restoration target physical link, and the communication interruption is further performed. A storage design is performed in which the sub λ path in which the s. The recovery procedure calculation unit 14 determines whether all the sub λ paths for which the communication disconnection has occurred can be accommodated (step S704). When it can not accommodate (step S704: NO), the restoration procedure calculation unit 14 returns the process to step S702. If it can be accommodated (step S704: YES), the recovery procedure calculation unit 14 ends the process of step S121. The restoration procedure calculated in each process of step S121 is output to the outside in step S105 of FIG.

  In the sixth embodiment, the process of calculating the restoration procedure in consideration of the restoration of both the wavelength path and the sub λ path has been described. However, a recovery procedure not considering the sub λ path may be calculated. That is, steps S102, S103, S104, S111, and S113 in the process shown in FIG. 2 may be omitted. In this case, in step S112, it is determined whether or not all the required number of wavelength paths can be accommodated in the communicable optical fiber, and if all the wavelength paths can be accommodated, the accommodation design is restored to the procedure storage unit The processing is ended by storing the restoration procedure as the restoration procedure 15 and when all the wavelength paths can not be accommodated, the process proceeds to step S121. In this case, in the process of step S121, the operation of step S702 replaces the operation of selecting a physical link to be added to the recovery target according to the number of wavelength paths accommodated in the physical link. The operation of step S703 replaces the operation of performing accommodation design in which the wavelength path in which the communication interruption has occurred is allocated to the fiber network including the communicable physical link and the physical link to be restored. In addition, the determination in step S704 replaces the determination as to whether all wavelength paths in which the communication interruption has occurred can be accommodated.

  In the sixth embodiment, among the physical links included in the shortest path between the start point and end point nodes, the restoration procedure is calculated by adding to the restoration target in order from the physical link having the largest number of accommodated paths. By recovering the fiber link composed of the optical fiber and the communication device according to the calculated recovery procedure, the fiber link where the paths are concentrated is preferentially recovered, and many wavelength paths and sub λ paths can be recovered. As a result, it is possible to reduce the time required for communication recovery when communication disconnection due to a failure of optical fibers connecting between communication devices occurs over a wide area.

  In each of the above-described embodiments, the calculation of the restoration procedure in the optical communication network in which the communication devices (nodes) are connected by the optical fiber has been described, but in the communication network in which the transmission medium capable of accommodating a plurality of paths is used for the physical link. A network management device may be used for recovery.

  By using the network management apparatus described in each of the above embodiments, in the case of a wide area disaster, the order of repairing or replacing the communication apparatus and the optical fiber with respect to a large number of communication apparatuses and the optical fiber requiring repair or replacement The recovery procedure shown is obtained. By repairing or replacing the communication device and the optical fiber in accordance with the obtained restoration procedure, it is possible to shorten the time required for the restoration of the optical communication network, and to quickly restore the optical communication network.

  All or part of the network management apparatus in each embodiment described above may be realized by a computer and a program. For example, a program for realizing each of the components included in the network management apparatus is recorded in a computer readable recording medium, and the computer system reads and executes the program recorded in the recording medium, and the program is realized. It is also good. Here, the “computer system” includes an OS and hardware such as peripheral devices. In addition, “computer readable recording medium” means non-temporary portable storage medium such as flexible disk, magneto-optical disc, ROM, CD-ROM, non-temporary such as hard disk built in computer system It refers to a storage device. Furthermore, the "computer-readable recording medium" dynamically holds a program for a short time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. It may also include one that holds a program for a certain period of time, such as volatile memory in a computer system that becomes a server or a client in that case. The program may be provided through a network, and the computer may receive and execute the program. Further, this program may be for realizing a part of the above-mentioned components, and the above-mentioned components can be realized in combination with a program already recorded in a computer system. It may be realized using hardware such as PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array).

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within the scope of the present invention.

  The present invention can also be applied to an application where it is essential to reduce the time required for communication recovery when communication breaks occur in a wide area due to a failure of an optical fiber connecting between communication devices.

  DESCRIPTION OF SYMBOLS 1 ... Network management apparatus, 11 ... Reception part, 12 ... Update part, 13 ... Network information storage part, 14 ... Recovery procedure calculation part, 15 ... Recovery procedure storage part, 16 ... Recovery procedure output part

Claims (7)

A network management apparatus in a communication network, comprising: a plurality of communication devices, a plurality of transmission paths connecting the communication devices, and a network management device.
A network storing network information including physical topology information indicating connection between the plurality of communication devices and the plurality of transmission paths, and path information indicating paths of the respective paths provided between the communication devices and presence or absence of a failure An information storage unit,
An updating unit configured to update the network information according to notification of occurrence of communication disconnection in the communication network;
A recovery procedure calculation unit that calculates an order of recovering the transmission path in which the communication disconnection has occurred based on the network information;
Equipped with
The recovery procedure calculation unit
The number of connections, which is the number of the transmission paths connected to each of the communication devices, is calculated, and among the transmission paths in which the communication interruption occurred, the communication devices having a large total value of the number of connections of the adjacent communication devices Determine the recovery target in order from the transmission path,
Network management device. The recovery procedure calculation unit
In the communication network, wherein the calculating a minimum spanning tree between the communication devices, wherein the transmission path, the recovery in preference to the pre-Symbol the transmission path that is not included in the minimum spanning tree target included before SL minimum spanning tree To decide
The network management device according to claim 1 . A network management apparatus in a communication network, comprising: a plurality of communication devices, a plurality of transmission paths connecting the communication devices, and a network management device.
A network storing network information including physical topology information indicating connection between the plurality of communication devices and the plurality of transmission paths, and path information indicating paths of the respective paths provided between the communication devices and presence or absence of a failure An information storage unit,
An updating unit configured to update the network information according to notification of occurrence of communication disconnection in the communication network;
A recovery procedure calculation unit that calculates an order of recovering the transmission path in which the communication disconnection has occurred based on the network information;
Equipped with
The recovery procedure calculation unit
In the communication network, the shortest path between the communication devices is calculated, and the transmission where the communication interruption has occurred, among the transmission paths included in the shortest path, the transmission having a large number of accommodated paths Determine the recovery targets in order from the road,
Network management device. A plurality of communication devices, wherein a plurality of transmission paths that connect the communication device, the plurality of communication devices and the plurality of transmission lines connecting the shown physical topology information and path of each of provided between the communication device a recovery procedure for determining how network management device performs in a communication network comprising a network management apparatus including a network information storage unit for storing network information including the path information indicating the presence or absence of a path and disorders,
An updating step of updating the network information in response to a notification of occurrence of communication disconnection in the communication network;
A restoration procedure calculation step of calculating an order of restoration of the transmission path in which the communication interruption has occurred based on the network information;
Have
In the recovery procedure calculation step,
The number of connections, which is the number of the transmission paths connected to each of the communication devices, is calculated, and among the transmission paths in which the communication interruption occurred, the communication devices having a large total value of the number of connections of the adjacent communication devices Determine the recovery target in order from the transmission path,
How to determine the recovery procedure. In the recovery procedure calculation step,
A minimum spanning tree between the communication devices in the communication network is calculated, and the transmission paths included in the minimum spanning tree are determined as recovery targets in preference to the transmission paths not included in the minimum spanning tree. ,
The recovery procedure determination method according to claim 4. Physical topology information indicating connection between a plurality of communication devices, a plurality of transmission paths connecting the communication devices, a plurality of the communication devices and the plurality of transmission paths, and a path provided between the communication devices A network management apparatus comprising: a network management apparatus storing a network information storage unit storing network information including a path and path information indicating presence or absence of a failure;
An updating step of updating the network information in response to a notification of occurrence of communication disconnection in the communication network;
A restoration procedure calculation step of calculating an order of restoration of the transmission path in which the communication interruption has occurred based on the network information;
Have
In the recovery procedure calculation step,
In the communication network, the shortest path between the communication devices is calculated, and the transmission where the communication interruption has occurred, among the transmission paths included in the shortest path, the transmission having a large number of accommodated paths Determine the recovery targets in order from the road,
How to determine the recovery procedure. A program for causing a computer to function as the network management device according to any one of claims 1 to 3 .

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