Optical network management device

Abstract

In order to shorten the time required for opening an optical path in an optical network that includes a plurality of domains and devices, this optical network management device comprises: an optical path evaluation unit that, when deleting a first optical path between transponders that are end points of an optical path, suspends deletion of one or more optical paths having a high probability of reuse among the first optical paths; and an optical path setting unit that, when opening a second optical path between the transponders, if a reusable optical path the deletion of which has been suspended is present on the path of the second optical path, opens the second optical path using the reusable optical path.

Description

Optical Network Management Device

[0001] The present invention relates to an optical network management device.

[0002] In an optical network, providing an end-to-end optical path requires control such as setting up all the devices and sections through which the optical path passes by issuing an activation order, which takes time to provide an end-to-end optical path.

[0003] Conventionally, as a method for speeding up order processing, a technique is known in which commands that can be issued in parallel are defined to shorten the command processing time until a path is opened (see, for example, Patent Document 1).

[0004] JP 2012-253582 A

[0005] However, in an optical network that includes multiple domains and devices, each domain or device may have a different equipment vendor, design policy, configuration procedure, etc., which means that commands cannot necessarily be issued in parallel, making it impossible to shorten the time it takes to open an optical path.

[0006] The embodiments of the present invention have been made in view of the above-mentioned problems, and reduce the time required to open an optical path in an optical network including a plurality of domains and devices.

[0007] In order to solve the above problems, an optical network management device according to an embodiment of the present invention includes an optical path evaluation unit that, when deleting a first optical path between transponders that are end points of the optical paths, postpones the deletion of one or more optical paths among the first optical paths that have a high probability of being reused, and an optical path setting unit that, when opening a second optical path between transponders, opens the second optical path using an optical path whose deletion has been postponed if that optical path is on the route of the second optical path.

[0008] According to an embodiment of the present invention, it is possible to reduce the time required to open an optical path in an optical network including a plurality of domains and devices.

[0009] FIG. 1 is a diagram illustrating an example of the configuration of an optical network management system according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the opening of an optical path according to a conventional example. FIG. 3 is a diagram illustrating the opening of an optical path according to an embodiment of the present invention. FIG. 4 is a diagram illustrating an example of the functional configuration of an optical network management device according to an embodiment of the present invention. FIG. 5 is a flowchart illustrating an example of an update process of an optical path evaluation DB according to an embodiment of the present invention. FIG. 6 is a diagram illustrating the update process of an optical path evaluation DB according to an embodiment of the present invention. FIG. 7 is a flowchart illustrating an example of a process when an optical path is deleted according to an embodiment of the present invention. FIG. 8 is a flowchart illustrating an example of a process when an optical path is opened according to an embodiment of the present invention. FIG. 9 is a diagram illustrating a setting process within a local domain according to an embodiment of the present invention. FIG. 10 is a flowchart illustrating an example of a process when optical resources are congested according to an embodiment of the present invention. FIG. 11 is a diagram illustrating an example of a process when a deletion order is made according to an embodiment of the present invention. FIG. 12 is a diagram illustrating an example of a process when an opening order is made according to an embodiment of the present invention.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0011] <System Configuration> Fig. 1 is a diagram showing an example of the configuration of an optical network control system according to this embodiment. The optical network management system 1 is a system that manages the provision of end-to-end optical paths that pass through multiple domains or EMSs (Equipment Management Systems) in an optical network.

[0012] In the example of FIG. 1, the optical network management system 1 includes EMSs 12a to 12e, reconfigurable optical add-drop multiplexers (ROADMs) 13a to 13i, transponders 20a to 20d, an optical network management device 10, and the like.

[0013] In the following description, "EMS 12" will be used to refer to any of the multiple EMSs 12a to 12e. Furthermore, "ROADM 13" will be used to refer to any of the multiple ROADMs 13a to 13i. Furthermore, "transponder 20" will be used to refer to any of the transponders 20a to 20d.

[0014] The EMS 12 is provided in each of the multiple domains 11a to 11e and is a management device that manages devices such as the ROADM 13 and transponder 20 within each domain. The ROADM 13 is a reconfigurable transmission device that achieves high-capacity transmission by wavelength multiplexing optical paths. The transponder 20 is a relay device that performs bidirectional conversion between optical signals and electrical signals at the end points of end-to-end optical paths. Here, an optical path is a route for an optical signal that occupies one wavelength.

[0015] The optical network management device 10 is a device or system that is communicatively connected to a plurality of EMSs 12 and is capable of transmitting control signals to each EMS 12 and acquiring information (device information, path information, etc.) from each EMS 12. The optical network management device 10 is realized, for example, by a service order system that manages service orders (SOs) such as optical path opening orders, change orders, and / or deletion orders. However, the optical network management device 10 is not limited to this, and may also be realized by another device (for example, a network orchestrator) that can similarly control the EMSs 12.

[0016] Each of the multiple domains 11a to 11e includes an EMS 12 and one or more ROADMs 13. In the following description, when referring to any of the multiple domains 11a to 11e, the term "domain 11" is used. Furthermore, Core, Metro, and Local of the multiple domains 11 indicate the hierarchical type of each domain 11.

[0017] 2 is a diagram illustrating the establishment of a conventional optical path. In the conventional technology, for example, when an end-to-end optical path 201 from transponder 20a to transponder 20d is opened, it is necessary to control EMSs 12a to 12d in all domains through which the path passes. This control includes, for example, route design, setting input to devices, and waiting time for the optical output level of the devices to stabilize. Because these controls must be performed on EMSs 12a to 12d in all domains through which the optical path requested by the opening order passes, it takes time to open the end-to-end optical path 201.

[0018] As a method for speeding up order processing, a technique has been proposed in which commands that can be issued in parallel are defined to shorten the command processing time until the path is opened (see, for example, Patent Document 1). However, parallelization is not easy for orders to open optical paths that pass through multiple domains due to the following reasons.

[0019] For example, each domain 11, EMS 12, and ROADM 13 may have different device vendors, design policies, configuration procedures, etc., and may also have different command functions and functional granularity for operating each device. Therefore, it is difficult to centrally control these devices using commands, and in some cases it is not possible to define commands that can be issued in parallel. Furthermore, if a system were to be built that takes these issues into consideration, significant development costs would be required, and operational costs would also be high because the system would need to be changed every time the network configuration or the controlled device is updated.

[0020] Therefore, the optical network management device 10 according to this embodiment has a function of suspending the deletion of one or more optical paths among the first optical paths that have a high probability of being reused when deleting a first optical path between transponders 20 that are the end points of the optical paths. Furthermore, when opening a second optical path between transponders 20, if there is an optical path on the route of the second optical path whose deletion has been suspended, the optical network management device 10 has a function of opening the second optical path using that optical path.

[0021] 3 is a diagram for explaining the opening of an optical path according to this embodiment. When deleting a first optical path (e.g., the optical path 201 in FIG. 2 ), the optical network management device 10 suspends the deletion of an optical path that is highly likely to be reused (e.g., the optical path 301 from the ROADM 13 a to the ROADM 13 i in FIG. 3 ) based on the history of past opening orders.

[0022] Furthermore, when opening a second optical path (for example, the optical path from transponder 20a to transponder 20c in FIG. 3), the optical network management device 10 opens the second optical path by utilizing the optical path 301 on the route whose deletion has been suspended. This allows the optical network management device 10 to only reset the optical path 302 in domain 11a and the optical path 303 in domain 11b, thereby reducing the time required to open an optical path.

[0023] In this way, the optical network management system 1 according to this embodiment can reduce the time required to open an optical path in an optical network including a plurality of domains 11 and devices.

[0024] <Functional Configuration of Optical Network Management Device> Fig. 4 is a diagram showing an example of the functional configuration of an optical network management device according to this embodiment. The optical network management device 10 is an information processing device having a computer configuration, or a system including multiple computers. The optical network management device 10 realizes, for example, each functional configuration shown in Fig. 4 by executing a predetermined program on the computer included in the optical network management device 10. In the example of Fig. 4, the optical network management device 10 includes an optical path evaluation unit 401, an optical path setting unit 402, a service order management unit 403, an SO history database (DB) 404, and an optical path evaluation DB 405. Note that at least a portion of each of the above functional configurations may be realized by hardware.

[0025] When deleting a first optical path between transponders 20, the optical path evaluation unit 401 executes an optical path evaluation process to reserve deletion of one or more optical paths among the first optical paths that have a high probability of being reused.

[0026] For example, the optical path evaluation unit 401 refers to the SO history DB 404, calculates the probability of opening each optical path based on the frequency of past opening orders, etc., and stores the calculation results in the optical path evaluation DB 405, etc. The SO history DB 404 holds the history of service orders (SO), such as opening orders, change orders, and deletion orders. The service order history also includes information such as the implementation time of past service orders, the order type, and end-to-end route information of the optical path.

[0027] Furthermore, when an optical path deletion order is placed, the optical path evaluation unit 401 refers to the optical path evaluation DB 405 and reserves the deletion of optical paths that have a high probability of being reused among the first optical paths to be deleted. Note that the specific processing content of the optical path evaluation unit 401 will be described later.

[0028] When opening a second optical path between transponders 20, if there is an optical path pending deletion on the route of the second optical path, the optical path setting unit 402 executes an optical path setting process to open the second optical path using that optical path. Note that the specific processing content of the optical path setting unit 402 will be described later.

[0029] The service order management unit 403 executes service order management processing for managing service orders such as activation orders, change orders, and deletion orders. For example, the service order management unit 403 receives a service order and notifies the optical path evaluation unit 401, the optical path setting unit 402, and the like of the received service order. Furthermore, the service order management unit 403 transmits control commands related to the activation, change, and deletion of optical paths to each EMS 12 in accordance with control from the optical path setting unit 402. Each EMS 12 controls the ROADM 13, the transponder 20, and the like based on the control commands received from the service order management unit 403.

[0030] 4 is an example of the functional configuration of the optical network management device 10. For example, the functional configuration of the optical network management device 10 shown in FIG. 4 may be distributed across multiple devices.

[0031] <Processing Flow> Next, the processing flow of optical network management according to this embodiment will be described.

[0032] 5 is a flowchart showing an example of an update process of the optical path evaluation DB according to the embodiment 1. This process shows an example of a process in which the optical path evaluation unit 401 refers to the SO history DB 404, calculates the opening probability of each optical path based on the frequency of past opening orders, etc., and updates the path evaluation DB 405 based on the calculation result.

[0033] In step S501, the optical path evaluation unit 401 acquires a log for a predetermined period of time in the past from the SO history DB 404. For example, the optical path evaluation unit 401 acquires a log 600 of an opening order from the SO history DB as shown in FIG.

[0034] In the example of FIG. 6 , the activation order log 600 includes, as items, information such as an “order number,” a “domain (m)” of point A, a “TRPN number (i)” of point A, a “domain (n)” of point Z, and a “TRPN number (j)” of point Z. The order number is a number, identification information, or the like, that identifies the activation order. The “domain (m)” is a name, identification information, or the like, that identifies the local domain that accommodates the transponder 20 at point A, which is one end point of the optical path that has been activated by the activation order. The “TRPN number (i)” is a name, identification information, or the like, that identifies the transponder 20 at point A. The “domain (n)” is a name, identification information, or the like, that identifies the local domain that accommodates the transponder 20 at point Z, which is the other end point of the optical path that has been activated by the activation order. The “TRPN number (j)” is a name, identification information, or the like, that identifies the transponder 20 at point Z.

[0035] In step S502, the optical path evaluation unit 401 calculates the path opening probability between each transponder 20 from the acquired log. For example, if the number of times a path is opened between transponders (i, j) is n ｉｊ Let N be the total number of path openings in the log, then the path opening probability p ｉｊ can be calculated using the following formula (1).

[0036] In step S503, the optical path evaluation unit 401 updates the data of the path opening probability between the transponders 20 in the optical path evaluation DB 405 based on the calculation result. For example, the optical path evaluation unit 401 updates the data of the path opening probability between the transponders 20 in the optical path evaluation DB 405 based on the calculation result. ｉｊ ) 601 and stores it in the optical path evaluation DB 405 .

[0037] In the example of FIG. 6, the inter-TRPN path opening probability (p ｉｊ ) 601 is in an adjacency matrix format, with the TRPN numbers of the transponders 20 at the end points of the optical paths as rows / columns, and the elements representing the optical path opening probability. However, this is a convenient representation for explaining the embodiment, and the matrix format is not necessarily required.

[0038] In step S504, the optical path evaluation unit 401 calculates the path establishment probability between the local domains from the acquired log. For example, if the number of times a path is established between the local domains (m, n) is n, ｍｎ Let N be the total number of path openings in the log, then the path opening probability p ｍｎ can be calculated by the following equation (2).

[0039] Here, m is the local domain of point A and n is the local domain of point Z.

[0040] In step S505, the optical path evaluation unit 401 updates the data of the path establishment probability between the local domains in the optical path evaluation DB 405 based on the calculation result. For example, the optical path evaluation unit 401 updates the data of the path establishment probability between the local domains (p ｍｎ ) 602 and stores it in the optical path evaluation DB 405 .

[0041] In the example of FIG. 6, the inter-local domain path opening probability (p ｍｎ ) 602 is in the form of an adjacency matrix in which the local domains of the end points of the optical paths are represented as rows / columns and the elements represent the optical path opening probability. However, this is a convenient representation for explaining the embodiment, and the matrix format is not necessarily required.

[0042] In this way, the optical path evaluation unit 401 extracts the log of past path opening orders, calculates the opening frequency of paths (between transponders 20) on the same route as the path being evaluated, and calculates and predicts the reuse probability of the path from the opening frequency of the paths for all orders.

[0043] However, in a large-scale optical network, it is expected that the frequency of path opening orders for the same route will be low, and a sufficient number of samples for prediction will not be collected. To address this issue, in the example of Figure 5, the optical path evaluation unit 401 calculates the opening frequency between local domains to which the transponder 20 belongs, assuming that partial optical path opening orders are feasible, and similarly calculates the path reuse probability. However, this processing is not essential. For example, the optical path evaluation unit 401 may calculate either the opening probability between transponders 20 or the opening probability between local domains, and update the optical path evaluation DB 405.

[0044] The path opening probability can also be calculated for each order. However, since each order does not have a significant effect, the optical path evaluation unit 401 may execute the process of FIG. 5 periodically (for example, once every half day or once a day) in order to shorten the calculation time.

[0045] 7 is a flowchart illustrating an example of processing when deleting an optical path according to the embodiment 1. This processing illustrates an example of processing that the optical path evaluation unit 401 executes when deleting an optical path in response to, for example, an optical path deletion order.

[0046] In step S701, the optical path evaluation unit 401 searches the optical path evaluation DB 405 using the transponder 20 at the end point of the optical path to be deleted as a key, and acquires the path opening probability A between the transponders 20.

[0047] In step S702, the optical path evaluation unit 401 determines whether the acquired path opening probability A is equal to or greater than a threshold P_tran (first threshold). Here, the threshold P_tran is a predetermined value for determining whether to suspend the deletion of the optical path between the transponders 20.

[0048] If the path establishment probability A is equal to or greater than the threshold P_tran, the optical path evaluation unit 401 shifts the process to step S703. On the other hand, if the path establishment probability A is not equal to or greater than the threshold P_tran, the optical path evaluation unit 401 shifts the process to step S705.

[0049] When the process proceeds from step S702 to step S703, the optical path evaluation unit 401 suspends deletion of the optical path (the optical path whose path opening probability A is equal to or greater than the threshold value P_tran). In step S704, the optical path evaluation unit 401 updates the data of the optical path suspended for deletion in the optical path evaluation DB 405.

[0050] On the other hand, when the process proceeds from step S702 to step S705, the optical path evaluation unit 401 searches the optical path evaluation DB 405 using the domain of the endpoint of the optical path to be deleted as a key, and acquires the path opening probability B between the local domains.

[0051] In step S706, the optical path evaluation unit 401 determines whether the acquired path opening probability B is equal to or greater than a threshold P_domain (second threshold). Here, the threshold P_domain is a predetermined value for determining whether to suspend the deletion of optical paths between local domains.

[0052] If the path opening probability B is equal to or greater than the threshold P_domain, the optical path evaluation unit 401 shifts the process to step S707. On the other hand, if the path opening probability B is not equal to or greater than the threshold P_domain, the optical path evaluation unit 401 shifts the process to step S708.

[0053] When the process proceeds from step S706 to step S707, the optical path evaluation unit 401 suspends deletion of the optical path (the optical path whose path opening probability B is equal to or greater than the threshold P_domain). Also, in step S704, the optical path evaluation unit 401 updates the data of the optical path suspended for deletion in the optical path evaluation DB 405.

[0054] When the process proceeds from step S706 to step S708, the optical path evaluation unit 401 deletes the optical path (the optical path to be deleted). In this case, the optical network management device 10 executes normal deletion order processing.

[0055] 7, when deleting a first optical path, if the probability of reusing the first optical path is equal to or greater than a first threshold, the optical path evaluation unit 401 can suspend the deletion of the first optical path. Also, when deleting the first optical path, if the probability of reusing an optical path between local domains that accommodates a transponder that is an endpoint of the first optical path is equal to or greater than a second threshold, the optical path evaluation unit 401 can suspend the deletion of an optical path between local domains.

[0056] The reason for determining whether to suspend deletion based on the transponder opening probability before the domain is that if there is a path opening order that matches the transponders at point A and / or point Z, there will be no need to reconnect the optical path in the local domain to which the matching endpoints belong.

[0057] One operational use case is when a user subscribes to multiple optical paths connecting point A and point Z, and when demand for the service is low, the number of optical paths is reduced, and when demand for the service increases, the number of the same optical paths is increased. Since transponders are generally tied to the bases owned by the user, it is thought that in many cases, when the same user changes their optical path contract (addition / deletion), the transponder is not changed. Another use case is a service format in which multiple users share a transponder, which can be considered as a case in which the probability of a path being opened between transponders is high.

[0058] The reason for determining whether to postpone deletion after a transponder is based on the domain's establishment probability is that the probability of establishing a path that matches the transponders is not expected to be that high, except for the use cases mentioned above. Therefore, by assuming the replacement of optical paths within a local domain, the path establishment probability can be increased by relaxing the conditions for reuse.

[0059] As an operational use case, for example, assume that local domains are defined in Tokyo and Sapporo, respectively, and that there is high demand for optical paths between Tokyo and Sapporo. Furthermore, since the transponder locations in Tokyo (e.g., data centers owned by users at locations in Otemachi, Akasaka, and Shinagawa) are expected to vary depending on the user's activation order, the probability of transponder path activation is not expected to be high. On the other hand, when considering the entire local domains in Tokyo and Sapporo, since many users' path activation orders occur between local domains, the probability of path activation between domains is expected to increase. In this case, the route from northern Kanto to Tohoku to southern Hokkaido (Hokkaido) becomes a core domain or metro domain, and optical paths in this section do not need to be set up in activation orders, thereby shortening the optical path activation time.

[0060] (Optical Path Evaluation DB Update Process) Fig. 8 is a flowchart showing an example of an optical path evaluation DB update process according to the first embodiment. It is desirable that the optical path evaluation unit 401 periodically executes the process shown in Fig. 8 to delete deletion-pending optical paths (optical paths for which deletion has been suspended) that have not been reused for a predetermined period of time, thereby releasing resources. Note that the following description will be given assuming that a deletion-pending flag is set for the deletion-pending optical paths in the optical path evaluation DB 405.

[0061] In step S801, the optical path evaluation unit 401 acquires optical paths for which a deletion pending flag has been set and whose deletion pending time has exceeded a threshold value T_del from the optical path evaluation DB 405. Here, the threshold value T_del is assumed to be a predetermined value for determining whether or not to delete a deletion pending optical path that has not been reused.

[0062] In step S802, the optical path evaluation unit 401 determines whether or not an optical path for which a deletion suspension flag is set and whose deletion suspension time exceeds the threshold T_del has been acquired. If an optical path has been acquired, the optical path evaluation unit 401 proceeds to step S803. On the other hand, if an optical path has not been acquired, the optical path evaluation unit 401 ends the processing of FIG. 8.

[0063] In step S803, the optical path evaluation unit 401 deletes the optical path (the optical path acquired in step S801).

[0064] In step S804, the optical path evaluation unit 401 updates the optical path evaluation DB 405. For example, the optical path evaluation unit 401 cancels the deletion pending flag setting in the optical path evaluation DB 405 for the optical path deleted in step S803.

[0065] By the process of FIG. 8, the optical path evaluation unit 401 can delete the deletion pending optical paths that have not been reused for a predetermined period of time, thereby freeing up resources.

[0066] 9 is a flowchart illustrating an example of processing when an optical path is opened according to the embodiment 1. This processing illustrates an example of processing that the optical path setting unit 402 executes when opening an optical path in response to an optical path opening order, for example.

[0067] In step S901, the optical path setting unit 402 searches the optical path evaluation DB 405 using the transponder 20 that is the end point of the optical path to be opened as a key.

[0068] In step S902, the optical path setting unit 402 determines whether there is a deletion pending path whose route matches the optical path to be opened. If there is a deletion pending path whose route matches, the optical path setting unit 402 shifts the process to step S903. On the other hand, if there is no deletion pending path whose route matches, the optical path setting unit 402 shifts the process to step S904.

[0069] When the process proceeds from step S902 to step S903, the optical path setting unit 402 provides the optical path (a deletion-pending path whose route matches the optical path to be opened) to the user, and the process proceeds to step S911.

[0070] When the process proceeds from step S902 to step S904, the optical path setting unit 402 searches the optical path evaluation DB 405 using as a key the domain that accommodates the transponder 20 that is the end point of the optical path to be opened.

[0071] In step S905, the optical path setting unit 402 determines whether there is a deletion pending path whose route matches the optical path between domains accommodating the transponder 20 that is the endpoint of the optical path to be opened. If there is no deletion pending path whose route matches, the optical path setting unit 402 shifts the process to step S906. On the other hand, if there is a deletion pending path whose route matches, the optical path setting unit 402 shifts the process to step S907.

[0072] When the process proceeds from step S905 to step S906, the optical path setting unit 402 sets a new optical path by a conventional method. For example, the optical path setting unit 402 executes processes such as route design, setting input to devices, and waiting for stabilization of the optical output level of the devices for the EMSs 12 of all domains through which the optical path to be opened passes.

[0073] When the process proceeds from step S905 to step S907, the optical path setting unit 402 determines whether the optical path to be opened and the optical path whose route between local domains matches are the same within the local domain on the point A side, which is one end point of the optical path to be opened. If the optical paths are not the same within the local domain on the point A side, the optical path setting unit 402 proceeds to step S908. On the other hand, if the optical paths are the same within the local domain on the point A side, the optical path setting unit 402 proceeds to step S909.

[0074] When the process proceeds from step S907 to step S908, the optical path setting unit 402 sets a new optical path within the local domain of point A.

[0075] 10 is a diagram illustrating an example of a setting process within a local domain according to the first embodiment. For example, the optical path setting unit 402 sets a new optical path from the ROADM 13x to the transponder 20x, which is point A, within the local domain 11x (step S1). The optical path setting unit 402 also switches the connection to the transponder 20x at the ROADM 23x, which is the connection point with the upper domain 11y (step S2). Furthermore, the optical path setting unit 402 deletes the deletion-pending optical path 1001, which is an unnecessary section within the local domain at point A (step S3). The process of step S3 may be performed later.

[0076] There are two methods for switching optical paths in a ROADM 13 in a local domain, depending on whether the ROADM 13 has a cross-connect function for optical connections (a function for switching to another port without terminating an existing optical path).

[0077] Method 1) If the ROADM 13 has a cross-connect function, the ROADM 13 can change the output destination of the optical path without changing the wavelength by using the cross-connect function.

[0078] Method 2) If ROADM 13 does not have a cross-connect function, ROADM 13 temporarily terminates the optical path (converts the optical signal to an electrical signal) and opens a new optical path within the local domain, thereby changing the output destination of the optical path.

[0079] In this embodiment, the output destination of the optical path can be switched using either method 1 or method 2. However, in method 2, an optical signal is converted to an electrical signal midway, which increases delays and the like compared to method 1.

[0080] 9, the explanation of the flowchart will be continued. In step S909, the optical path setting unit 402 determines whether the optical path to be opened and the optical path whose route between local domains matches are the same within the local domain on the Z point side, which is the other end point of the optical path to be opened. If the optical paths are not the same within the local domain on the Z point side, the optical path setting unit 402 shifts the processing to step S910. On the other hand, if the optical paths are the same within the local domain on the Z point side, the optical path setting unit 402 shifts the processing to step S911.

[0081] When the process proceeds from step S909 to step S910, the optical path setting unit 402 sets a new optical path within the local domain of point Z, for example, in the same manner as in the process of step S908.

[0082] When the process proceeds to step S911, the optical path setting unit 402 updates the optical path evaluation DB 405. For example, the optical path setting unit 402 deletes, from the optical path evaluation DB 405, information about the deletion pending path used to open the new optical path (for example, the deletion pending flag, the deletion pending time, and the path opening probability).

[0083] 9, when opening a second optical path, if the optical paths pending deletion include an optical path between transponders that are endpoints of the second optical path, the optical path setting unit 402 can open the optical path as the second optical path. Furthermore, when opening a second optical path, if the optical paths pending deletion include an optical path between local domains that accommodate transponders that are endpoints of the second optical path, the optical path setting unit 402 can open the second optical path using the optical path.

[0084] (Processing when optical resources are scarce) An optical path that the optical path evaluation unit 401 has reserved for deletion cannot be used for other path opening orders until it is either deleted due to a timeout by the processing in Figure 8 or reused by the optical path setting unit 402.

[0085] On the other hand, in actual operation, it is necessary to deal with an increase in the number of accommodated users or an increase in the number of optical paths with limited facilities (ROADM, optical fiber, number of optical wavelengths, etc.). Therefore, when the number of accommodated users or the number of optical paths increases, it is expected that a new optical path cannot be established and an activation order cannot be processed unless a route with a deletion pending flag is used.

[0086] In such a case, it is desirable that the optical path evaluation unit 401 releases the optical path that has been put on hold for deletion, for example, by the process of FIG. 11, and operates so as to give priority to the optical path for which a new opening order has been placed.

[0087] 11 is a flowchart illustrating an example of processing when optical resources are tight according to the embodiment 1. This processing illustrates an example of processing when optical resources are tight, which is executed by the optical path evaluation unit 401, for example, when it is determined that there is a shortage of optical wavelengths for an opening order.

[0088] In step S1101, the optical path evaluation unit 401 checks whether the optical path of the opening order can be established by using the optical wavelength of the optical path route for which the deletion flag is set.

[0089] In step S1102, the optical path evaluation unit 401 determines, based on the check result of step S1101, whether the optical path of the activation order can be opened by using a part of the optical path with the deletion flag. If the optical path of the activation order can be opened by using a part of the optical path with the deletion flag, the optical path evaluation unit 401 proceeds to step S1103. On the other hand, if the optical path of the activation order cannot be opened even by using a part of the optical path with the deletion flag, the optical path evaluation unit 401 ends the processing of FIG. 11.

[0090] In step S1103, the optical path evaluation unit 401 deletes optical paths that are necessary to open the optical path in the opening order from among the optical paths with the deletion flag.

[0091] In step S1104, the optical path evaluation unit 401 updates the optical path evaluation DB 405. For example, the optical path evaluation unit 401 deletes from the optical path evaluation DB 405 information such as the deletion suspension flag and the deletion suspension time related to the deleted optical path.

[0092] 11, the optical network management device 10 can effectively utilize the optical paths that are pending deletion when optical resources become tight. For example, after completing the processing of FIG. 11, the optical path setting unit 402 executes the processing for opening an optical path described in FIG. 9.

[0093] Second Embodiment In the first embodiment, an example has been described in which an optical path between transponders 20 or an optical path between local domains is reused, but the optical path to be reused is not limited to this.

[0094] 12 is a diagram illustrating an example of processing when an optical path deletion order is made according to the second embodiment. For example, when deleting a first optical path between the transponder 20a at point A and the transponder 20c at point Z, the optical path evaluation unit 401 reserves the deletion of one or more optical paths 1201 among the first optical paths that have a high probability of opening (high probability of reuse). On the other hand, the optical path evaluation unit 401 deletes an optical path 1202 among the first optical paths that has a low probability of opening (low probability of reuse).

[0095] For example, the optical path evaluation unit 401 can calculate the probability of opening an optical path between ROADMs 13 in the same manner as in Example 1 by setting the ID (row / column item) of each node in the adjacency matrix of the path opening probability described in Figure 6 to the ID of ROADM 13.

[0096] 13 is a diagram for explaining processing at the time of an optical path opening order according to the second embodiment. For example, in FIG. 12, after deferring the deletion of one or more optical paths 1201 with a high probability of reuse, a second optical path between transponder 20e at point A and transponder 20d at point Z is opened as shown in FIG. 13. At this time, if an optical path 1301 whose deletion has been deferred exists on the route of the second optical path, the optical path setting unit 402 opens the second optical path using the optical path 1301. This allows the optical path setting unit 402 to omit setting the optical path 1301 whose deletion has been deferred.

[0097] In addition, in Example 2, when the number of ROADM13 devices is large, the size of the adjacency matrix increases to N^2, so it is desirable to consider the possibility that it may take time to calculate the optical path opening probability and to perform optical path calculation (based on an algorithm) that makes the most of partial optical paths.

[0098] In addition, in Example 2, in cases where optical paths can be reused only for a small portion of the sections between point A and point Z that are opened by an opening order, it is desirable to consider the possibility that the effect of shortening the optical path opening time may be reduced compared to setting up new optical paths for the entire section.

[0099] As described above, the present embodiment can be applied to and modified in various ways. For example, in the above embodiments, the optical network management device 10 has been described as reusing optical paths, but the scope of reuse is not limited to optical paths and may be expanded to include, for example, the settings of each optical fiber, the settings of optical cores, or the settings of interfaces in a ROADM.

[0100] In this case, for example, in Example 2, implementation is possible by assigning an ID to each of the interfaces of the optical fiber, the optical core, and the ROADM, and using this as an adjacency matrix. In this case, it is preferable to make it possible to acquire information that can identify the optical fiber, the optical core, and the ROADM from a log, a DB, or the like.

[0101] <Hardware Configuration> The optical network management device 10 according to this embodiment has, for example, the hardware configuration of a computer 1400 as shown in Fig. 14. Alternatively, the optical network management device 10 is realized by a plurality of computers 1400.

[0102] Fig. 14 is a diagram showing an example of the hardware configuration of a computer. In the example of Fig. 14, a computer 1400 includes a processor 1401, a memory 1402, a storage device 1403, a communication device 1404, an input device 1405, an output device 1406, a bus B, etc.

[0103] The processor 1401 is, for example, an arithmetic unit such as a CPU (Central Processing Unit) that executes predetermined programs to realize various functions. The memory 1402 is a storage medium readable by the computer 1400, and includes, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory). The storage device 1403 is a computer-readable storage medium, and may include, for example, a HDD (Hard Disk Drive), an SSD (Solid State Drive), various optical disks, and magneto-optical disks.

[0104] The communication device 1404 includes one or more pieces of hardware (transmitting / receiving devices) for communicating with other devices via a wireless or wired network. The input device 1405 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts input from the outside. The output device 1406 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside.

[0105] The bus B is commonly connected to the above components and transmits, for example, address signals, data signals, and various control signals. The processor 1401 may include, in addition to (or instead of) a CPU, for example, a DSP (Digital Signal Processor), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0106] The above program may be for realizing some of the above-described functions, or may be capable of realizing the above-described functions in combination with a program already stored in the computer 1400. Furthermore, some or all of the functions of the optical network management system 1 may be realized using hardware such as a programmable logic device (PLD) or a field programmable gate array (FPGA).

[0107] According to the present embodiment, it is possible to reduce the time required to open an optical path in an optical network including multiple domains and devices. For example, in the present embodiment, the number of domains controlled when providing an optical path and the number of associated devices such as EMS 12 and ROADM 13 are reduced, so that the number of work steps for opening an optical path is reduced, and the time required to open an optical path can be reduced.

[0108] Summary of Embodiments This specification discloses at least the optical network management device of the following paragraphs: (Item 1) An optical network management device comprising: an optical path evaluation unit that, when deleting a first optical path between transponders that are endpoints of an optical path, suspends deletion of one or more optical paths among the first optical paths that have a high probability of being reused; and an optical path setting unit that, when opening a second optical path between transponders, opens the second optical path using an optical path whose deletion has been suspended if the optical path is on the route of the second optical path. (Item 2) The optical path evaluation unit suspends deletion of the first optical path when deleting the first optical path if the probability of reusing the first optical path is equal to or greater than a first threshold; and the optical path setting unit, when opening the second optical path, opens the optical path as the second optical path if the optical paths whose deletion has been suspended include an optical path between transponders that are endpoints of the second optical path. 3. The optical network management device according to claim 1, wherein the optical path evaluation unit suspends the deletion of the optical path between the local domains if a probability of reusing an optical path between the local domains accommodating a transponder that is an endpoint of the first optical path is equal to or greater than a second threshold when deleting the first optical path, and the optical path setting unit opens the second optical path by reconfiguring an optical path within the local domain using an optical path that is among the optical paths suspended for deletion, if such an optical path is between the local domains accommodating a transponder that is an endpoint of the second optical path when opening the second optical path. 4. The optical network management device according to any of claims 1 to 3, wherein the optical path evaluation unit calculates the probability of reuse based on a history of past optical path openings, and deletes optical paths with a low probability of reuse and optical paths for which a predetermined time has elapsed since deletion was suspended.

[0109] (Clause 5) An optical network management method in which a computer executes the following steps: an optical path evaluation process that, when deleting a first optical path between transponders that are end points of the optical paths, postpones the deletion of one or more optical paths among the first optical paths that have a high probability of being reused; and an optical path setting process that, when opening a second optical path between transponders, opens the second optical path using an optical path that has been postponed for deletion if that optical path is on the route of the second optical path.

[0110] (Clause 6) A program, or a storage medium having a program stored thereon, that causes a computer to execute the following steps: an optical path evaluation process that, when deleting a first optical path between transponders that are the end points of an optical path, postpones the deletion of one or more optical paths among the first optical paths that have a high probability of being reused; and an optical path setting process that, when opening a second optical path between transponders, opens the second optical path using an optical path that has been postponed for deletion if that optical path is on the route of the second optical path.

[0111] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0112] REFERENCE SIGNS LIST 1 Optical network management system 10 Optical network management device 11, 11a to 11e Domain 12, 12a to 12e EMS 13, 13a to 13i ROADM 20, 20a to 20e Transponder 401 Optical path evaluation unit 402 Optical path setting unit 404 SO history DB 405 Optical path evaluation DB 1400 Computer

Claims

1. When deleting a first optical path between transponders that are endpoints of an optical path, an optical path evaluation unit that holds off on deleting one or more optical paths in the first optical path that have a high probability of being reused; and when establishing a second optical path between transponders, an optical path setting unit that, if there is an optical path for which deletion has been held off on the path of the second optical path, uses that optical path to establish the second optical path. An optical network management device having these components.

2. When deleting the first optical path, the optical path evaluation unit holds off on deleting the first optical path if the probability of reusing the first optical path is equal to or greater than a first threshold value. When establishing the second optical path, the optical path setting unit, if there is an optical path between transponders that are endpoints of the second optical path among the optical paths for which deletion has been held off, uses that optical path to establish the second optical path. The optical network management device according to claim 1.

3. When deleting the first optical path, the optical path evaluation unit holds off on deleting the optical path between local domains that contain the transponders that are endpoints of the first optical path if the probability of reusing the optical path between local domains is equal to or greater than a second threshold value. When establishing the second optical path, the optical path setting unit, if there is an optical path between local domains that contain the transponders that are endpoints of the second optical path among the optical paths for which deletion has been held off, uses that optical path to reconfigure the optical path within the local domain, thereby establishing the second optical path. The optical network management device according to claim 1 or 2.

4. The optical path evaluation unit calculates the probability of reuse based on the history of optical path establishment in the past, and deletes optical paths with a low probability of reuse and optical paths for which a predetermined amount of time has elapsed after holding off on deletion. The optical network management device according to claim 1.

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