Optical path setting device, optical path setting method, and program

Abstract

An optical path setting device 10 holds: existing order information that includes route information and a service type; and connection information of an optical transmission network. Upon receipt of input for a new order to set up a new optical path in an optical transmission network, the optical path setting device 10: searches for an existing order, of the same service type as the new order, that passes through the start point and the end point of the path of the new order; when the path of the new order is uniquely determined from the search result, determines the path of the new order on the basis of the path of the existing order obtained from the search; and when the path of the new order is not uniquely determined from the search result, determines the path of the new order so that the wavelength utilization rate in the optical transmission network becomes minimum.

Description

Optical path setting device, optical path setting method, and program

[0001] The present disclosure relates to an optical path setting device, an optical path setting method, and a program.

[0002] In optical transmission networks, the number of wavelengths that can be transmitted on a single optical fiber is limited. When allocating new paths, one solution to efficiently accommodate traffic demand under this constraint is to distribute wavelength usage by, for example, prioritizing allocation of paths with more unused wavelengths.

[0003] Regarding path allocation methods, prior art includes a path allocation method (Patent Document 1) that efficiently utilizes a limited number of wavelengths by dividing the time periods in which wavelengths are used and allocating wavelengths accordingly, a control device that allocates paths based on network quality information (Patent Document 2), and a method that allocates the shortest path when communication devices with multiple functions are mixed (Patent Document 3).

[0004] International Publication No. 2022 / 085147 International Publication No. 2021 / 166015 Japanese Patent Application Laid-Open No. 2012-244592

[0005] For the purpose of simplifying network operation and management, it may be better to allocate similar services to the same route rather than distributing wavelength usage. However, conventional technology did not take into account allocating similar services to the same route, which made it difficult to streamline operation and management.

[0006] The present disclosure has been made in view of the above, and aims to realize a method for setting up optical paths that efficiently utilize wavelengths while improving the efficiency of operation and management.

[0007] An optical path setting device of one embodiment of the present disclosure is an optical path setting device that sets an optical path in an optical transmission network, and retains information on existing paths including route information and service types, as well as connection information for the optical transmission network.When it receives an instruction to set a new optical path in the optical transmission network, it searches for an existing path that passes through the start and end points of the optical path and has the same service type as the optical path, and if the search results uniquely determine the optical path, it determines the optical path based on the existing path obtained by the search, and if the search results do not uniquely determine the optical path, it determines the optical path so as to minimize the wavelength utilization rate in the optical transmission network.

[0008] According to the present disclosure, it is possible to realize a method for setting optical paths that efficiently utilizes wavelengths while improving the efficiency of operation and management.

[0009] FIG. 1 is a diagram showing an example of the configuration of an optical path setting device of this embodiment. FIG. 2 is a flowchart showing an example of the process flow for allocating a path to a new order. FIG. 3 is a flowchart showing an example of the process flow for selecting a path for a new order. FIG. 4 is a diagram showing an example of a network configuration of an embodiment. FIG. 5 is a diagram showing an example of a network table. FIG. 6 is a diagram showing an example of an order table. FIG. 7 is a diagram showing an example of a new order. FIG. 8 is a diagram showing an example of the results of comparison between the proposed method and the comparative method. FIG. 9 is a diagram showing an example of the hardware configuration of an optical path setting device.

[0010] [Configuration of Optical Path Setting Device] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0011] 1 is a diagram showing an example of the configuration of an optical path setting device 10 according to the present embodiment. The optical path setting device 10 shown in the figure includes a reception unit 11, a pre-processing unit 12, a route allocation unit 13, a setting input unit 14, and a database (DB) 15.

[0012] The reception unit 11 is an interface for maintenance personnel, and receives the registration of new orders, presents route allocation results for the new orders, and receives approval for the allocation results. A new order is a new traffic demand for the optical transmission network, and includes, for example, the start and end points of a path (also called a route) and a service type. The start and end points are nodes (network devices) on the optical transmission network. The service type is, for example, the purpose of the path and service quality requirements.

[0013] The reception unit 11 receives registration of the network (NW) state in advance and registers the current NW state in the DB 15 .

[0014] The pre-processing unit 12 receives a route allocation instruction for a new order from the reception unit 11, and searches DB 15 for paths of the existing orders that pass through the start point and end point of the new order and have the same service type, thereby narrowing down the candidates for the path for the new order. If there is only one path candidate, the pre-processing unit 12 confirms that candidate as the path for the new order and transmits the route allocation result to the reception unit 11. The route allocation result includes information on the confirmed path.

[0015] The route allocation unit 13 receives a new order for which a path has not been determined from the pre-processing unit 12, searches for a path that minimizes the wavelength utilization rate in each link connecting the start and end nodes of the new order, and transmits the path obtained by the search as a route allocation result to the reception unit 11. The wavelength utilization rate can be calculated by dividing the sum of the number of wavelengths already used and the number of wavelengths to be used in the new order by the total number of wavelengths that can be accommodated.

[0016] The maintenance person can approve or reject the route allocation result. If the maintenance person approves the allocation result, the reception unit 11 issues a setting input instruction to the setting input unit 14 to set the path indicated in the route allocation result.

[0017] The setting input unit 14 receives a setting input instruction from the reception unit 11, inputs settings to each node (e.g., optical switch or terminal node) on the optical transmission network so that a path for a new order is set on the optical transmission network, and registers the set path information in DB 15.

[0018] The DB 15 stores connection information and the current network status including the paths and service types of existing orders. For example, the DB 15 stores a network table including links between nodes and the number of available wavelengths in each link, and an order table including the start points, end points, service types, and routes of existing orders.

[0019] [Optical Path Allocation Processing] Next, an example of optical path allocation processing will be described with reference to the flowchart of FIG.

[0020] In step S11, the reception unit 11 receives an input from a maintenance person.

[0021] In step S12, the reception unit 11 determines the content of the input and issues an instruction to the corresponding processing unit. For example, inputs received by the reception unit 11 include network status registration, new order registration, and approval of allocation results. If the input is new order registration, the reception unit 11 instructs the pre-processing unit 12 to allocate a path for the new order, and if the input is approval of allocation results, the reception unit 11 instructs the setting input unit 14 to input path settings.

[0022] If the input is for registering a network status, in step S21, the reception unit 11 registers the input network status in the DB 15, and ends the process.

[0023] If the input is a new order registration, in step S13, the pre-processing unit 12 determines whether or not to use an existing path of the same service type as the path for the new order. In other words, it determines whether or not to perform processing by the pre-processing unit 12. Whether or not to use a path for the existing order can be selected according to the operation policy of the network. Whether or not to use a path for the existing order may be set in advance in the optical path setting device 10, or whether or not to use a path for the existing order may also be accepted when accepting the registration of a new order.

[0024] If an existing path of the same service type is not to be used, the process of the pre-processing unit 12 is not executed and the process proceeds to step S16.

[0025] If an existing path of the same service type is to be used, in step S14, the pre-processing unit 12 refers to the DB 15 to search for a path that passes through the start point and end point of the new order and has the same service type as the new order. The details of the processing of step S14 will be described later.

[0026] In step S15, the pre-processing unit 12 determines whether the path for the new order is determined based on the search results of step S14. Specifically, if there is only one path among the paths of existing orders that passes through the start point and end point of the new order and has the same service type as the new order, the path for the new order is determined. If there is no existing order that meets the above conditions or if there are multiple existing orders, the path for the new order is not determined.

[0027] If multiple new orders are input, the processes in steps S14 and S15 are performed for each new order.

[0028] In step S16, the pre-processing unit 12 transmits the path of the new order for which the path has been determined to the reception unit 11. The reception unit 11 presents the path of the new order as a route allocation result.

[0029] A new order for which a path has not yet been determined is input to the route allocation unit 13 .

[0030] For a new order for which a path has not been determined, in step S17, the route allocation unit 13 refers to the network status stored in the DB 15 and calculates a path that minimizes the wavelength utilization rate. Minimization of the wavelength utilization rate will be described later.

[0031] If there are multiple existing orders in the search result of step S14, the route allocation unit 13 may determine a path for the new order from among the paths of the multiple existing orders in the search result.

[0032] In step S18, the route allocation unit 13 determines whether the wavelength utilization rate of the path of the new order calculated in step S17 exceeds 100%.

[0033] If the wavelength utilization rate does not exceed 100%, in step S16, the route allocation unit 13 transmits the calculated path of the new order to the reception unit 11. The reception unit 11 presents the path of the new order as a route allocation result.

[0034] If the wavelength utilization rate exceeds 100%, the route allocation unit 13 in step S19 notifies the maintenance person via the reception unit 11 of the lack of paths.

[0035] When the route allocation result is presented, the maintenance person checks the route allocation result for the new order and inputs approval of the allocation result into the reception unit 11 .

[0036] When the reception unit 11 receives an input of approval of the allocation result from the maintenance person in step S11, the reception unit 11 instructs the setting input unit 14 to input the setting of the approved path in step S12.

[0037] In step S31, the setting input unit 14 registers the information of the approved path in the DB 15.

[0038] In step S32, the setting input unit 14 inputs the settings to the devices on all the approved paths.

[0039] Next, an example of a process for searching for a candidate path through which a service of the same type as a new order will pass will be described with reference to the flowchart in Fig. 3. The process in Fig. 3 is executed for all input new orders.

[0040] In step S141, the pre-processing unit 12 reads the network status including the connection information and the information of the existing order from the DB 15.

[0041] In step S142, the pre-processing unit 12 determines whether or not there is an existing order with the same service type as the new order. If there is no existing order with the same service type, the pre-processing unit 12 proceeds to step S146 and marks the new order as an undetermined route.

[0042] In step S143, the pre-processing unit 12 determines whether a path for the new order can be uniquely determined for existing orders of the same service type. Specifically, the pre-processing unit 12 determines whether, among the paths for existing orders of the same service type as the new order, there is only one path that passes through the start point and end point of the new order. If there are multiple paths or no path, the pre-processing unit 12 proceeds to step S146 and marks the new order as having an undetermined path.

[0043] In step S144, the pre-processing unit 12 refers to the network status and determines whether or not there is an available wavelength on the path obtained in step S143. If there is no available wavelength, the pre-processing unit 12 proceeds to step S146 and sets the route of the new order as undetermined.

[0044] If a path for an existing order exists that satisfies all the conditions in steps S142 to S144, in step S145, the pre-processing unit 12 determines that path as a path for the new order and confirms the route for the new order.

[0045] The pre-processing unit 12 repeats the processes of steps S141 to S146 for all new orders and classifies each new order into a route-determined one and a route-undetermined one. The new orders classified as a route-undetermined one are input to the route allocation unit 13.

[0046] [Minimizing Wavelength Utilization Rate] Next, an example of minimizing wavelength utilization rate will be described.

[0047] An existing route wavelength allocation method can be used for minimizing the wavelength utilization rate performed by the route allocation unit 13. An example of minimizing the wavelength utilization rate will be described below.

[0048] The route allocation unit 13 receives a service α x The number of wavelengths required from the start point s to the end point d is O αx sd , Service α for existing orders x The number of wavelengths used from the start point s to the end point d is O αx sd (Bar over O), O αx sd(Bar above O) The number of wavelengths used in link ij is λ ij (bar above λ), and the number of wavelengths available on link ij, P ij In addition, when minimizing the distance of the entire route, the distance d on link ij is input. ij Also enter.

[0049] The route allocation unit 13 finds a route that minimizes the maximum value of the wavelength utilization rate of links, including existing paths, so that the number of wavelengths available on the links between each node is distributed and the following objective function is minimized.

[0050]

[0051] where r max , r min , r is the maximum wavelength utilization rate of each link, and max and min represent the maximum and minimum values ​​that can be taken. length max , length min , length is the maximum total distance of each path, and max and min represent the maximum and minimum possible values. c1 and c2 are coefficients. If the distance of the entire path is not to be minimized, only the first term of the above objective function is minimized.

[0052] When minimizing the objective function, the following constraints are considered:

[0053] At a relay node on a route, the number of outgoing routes is equal to the number of incoming routes.

[0054]

[0055] At the source node on a route, the number of outgoing paths is equal to the number of wavelengths required in the order (and vice versa for the destination node).

[0056]

[0057] At relay nodes on the route, there is no need for multiple nodes to enter or exit, meaning the route does not branch off along the way.

[0058]

[0059] λ (with a hat on top) is a value that takes on the value 0 or 1, indicating whether or not a wavelength is in use on the link.

[0060] At the start node on a path, there are no exits to multiple nodes (and vice versa for the end node).

[0061]

[0062] The number of wavelengths used in link ij is the number of available wavelengths P ij *It will be less than r.

[0063]

[0064] λ never exceeds O. In other words, λ (with a hat) takes a value between 0 and 1.

[0065]

[0066] When minimizing the overall path distance, the following constraints are also taken into account:

[0067] The total distance of the routes of each order is less than or equal to length.

[0068]

[0069] [Example] Next, the effects of this embodiment will be described using an example.

[0070] As shown in Fig. 4, the optical transmission network of the embodiment includes six nodes 1 to 6, and each node is connected by eight links. Specifically, nodes 1 and 2, nodes 1 and 5, nodes 2 and 3, nodes 2 and 5, nodes 3 and 4, nodes 3 and 6, nodes 4 and 6, and nodes 5 and 6 are connected by links 12, 15, 23, 25, 34, 36, 46, and 56, respectively. The wavelength utilization rate of each link in Fig. 4 is shown in parentheses.

[0071] The NW table is shown in Figure 5. The NW table stores the number of wavelengths available for each link. The number of wavelengths available for each link is 10.

[0072] The order table is shown in Figure 6. The order table holds the start point, end point, service type, and route for existing orders. The order table in Figure 6 contains four existing orders 1 to 4.

[0073] The network status including the connection status, the network table, and the order table is stored in the DB 15.

[0074] In the network state shown in Figures 4 to 6, suppose two new orders 1 and 2 shown in Figure 7 are input to the reception unit 11. New order 1 has a start point of node 1, an end point of node 4, and a service type of A. New order 2 has a start point of node 4, an end point of node 2, and a service type of B.

[0075] For new order 1, the pre-processing unit 12 searches the order table for existing orders 1 and 3 with service type A. The path for existing order 1 is 1-2-5, which does not pass through the end point (node ​​4) of new order 1. The path for existing order 3 is 1-2-3-4, which passes through the start point (node ​​1) and end point (node ​​4) of new order 1. The pre-processing unit 12 sets the path for existing order 3 as a candidate path for new order 1. Since the only candidate path for new order 1 is the path for existing order 3, the pre-processing unit 12 determines the path for existing order 3 to be the path for new order 1.

[0076] For new order 2, the pre-processing unit 12 searches the order table for existing orders 2 and 4 with service type B. The path for existing order 2 is 2-5-6, which does not pass through the start point (node ​​4) of new order 2. The path for existing order 4 is 6-5-2-1, which does not pass through the start point (node ​​4) of new order 2. Since none of existing orders 2 and 4 pass through the start point or end point of new order 2, the pre-processing unit 12 classifies new order 2 as having an undetermined route and inputs it to the route assignment unit 13.

[0077] The route allocation unit 13 calculates 4-3-2 for the path of the new order 2, which has the smallest wavelength utilization rate.

[0078] The reception unit 11 receives information on paths to be assigned to new orders 1 and 2 from the pre-processing unit 12 and the route assignment unit 13, respectively, and presents the results of the route assignment to the maintenance person.

[0079] When the maintenance person approves the allocation result, the setting input unit 14 registers the information of new orders 1 and 2 in the order table of DB 15 and inputs the settings to each node 1 to 6 on the optical transmission network to set up paths for new orders 1 and 2.

[0080] 8 shows the results of the proposed method of this embodiment and a comparative method for minimizing wavelength utilization rates. As described above, in the proposed method, the path for new order 1 was calculated as 1-2-3-4, and the path for new order 2 was calculated as 4-3-2. The comparative method is a method for calculating the path with the minimum wavelength utilization rate without performing processing by the pre-processing unit 12. In the comparative method, the path for new order 1 was calculated as 1-5-6-4, and the path for new order 2 was calculated as 4-3-2.

[0081] In an actual operation scenario, the path for new order 1 is designed to be 1-2-3-4, and the path for new order 2 is designed to be 4-6-5-2, so that services of the same type are assigned to the same route as much as possible.

[0082] The proposed method calculated the same path as the actual operation for new order 1, and calculated a path with a difference of three links from the actual operation path for new order 2. The comparison method calculated a path with a difference of three links from the actual operation path for both new orders 1 and 2.

[0083] Furthermore, the maximum wavelength utilization rate of the path calculated by the proposed method was 40%, while the maximum wavelength utilization rate of the path calculated by the comparative method was 30%.

[0084] Although the proposed method increased the maximum wavelength utilization rate compared to the comparison method, it was able to calculate a path with a small difference from the path designed in actual operational scenarios. By using the proposed method, it is expected that operational efficiency will be improved in addition to simply distributing wavelength usage.

[0085] As described above, the optical path setting device 10 of this embodiment holds information on existing orders, including route information and service types, and connection information on the optical transmission network. When a new order for setting a new optical path in the optical transmission network is received, the optical path setting device 10 searches for existing orders of the same service type as the new order, passing through the start and end points of the path of the new order. If the search results uniquely determine a path for the new order, the optical path setting device 10 determines a path for the new order based on the path of the existing order obtained by the search. If the search results do not uniquely determine a path for the new order, the optical path setting device 10 determines a path for the new order so as to minimize the wavelength utilization rate in the optical transmission network. This makes it possible to realize an optical path setting method that efficiently uses wavelengths while improving the efficiency of operation and management.

[0086] The optical path setting device 10 described above can be, for example, a general-purpose computer system including a central processing unit (CPU) 901, a memory 902, a storage 903, a communication device 904, an input device 905, and an output device 906, as shown in Fig. 9. In this computer system, the optical path setting device 10 is realized by the CPU 901 executing a predetermined program loaded onto the memory 902. This program can be recorded on a computer-readable non-transitory recording medium such as a magnetic disk, an optical disk, or a semiconductor memory, or can be distributed via a network.

[0087] 10 Optical path setting device 11 Reception unit 12 Pre-processing unit 13 Route allocation unit 14 Setting input unit 15 Database (DB)

Claims

1. An optical path setting device that sets an optical path in an optical transmission network, which holds information on existing paths including route information and service types, and connection information on the optical transmission network, and when it receives an instruction to set a new optical path in the optical transmission network, it searches for an existing path that passes through the start point and end point of the optical path and has the same service type as the optical path, and if the search result uniquely determines the optical path, it determines the optical path based on the existing path obtained by the search, and if the search result does not uniquely determine the optical path, it determines the optical path so that the wavelength utilization rate in the optical transmission network is minimized.

2. An optical path setting device according to claim 1, wherein, when the search results do not include the existing path and when the search results include multiple existing paths, the optical path is determined so as to minimize wavelength utilization in the optical transmission network.

3. An optical path setting device according to claim 2, wherein, when the search result includes a plurality of the existing paths, the optical path is determined based on one of the plurality of existing paths.

4. An optical path setting device as described in claim 1, wherein, when the determined optical path is approved, the optical path is set in the optical transmission network by inputting settings to a device on the optical transmission network, and information about the optical path is retained as information about the existing path.

5. An optical path setting method by an optical path setting device that sets an optical path in an optical transmission network, comprising: retaining information on existing paths including route information and service types, and connection information of the optical transmission network; upon receiving an instruction to set a new optical path in the optical transmission network, searching for an existing path that passes through the start point and end point of the optical path and has the same service type as the optical path; if the search result uniquely determines the optical path, determining the optical path based on the existing path obtained by the search; if the search result does not uniquely determine the optical path, determining the optical path so as to minimize the wavelength utilization rate in the optical transmission network.

6. A program for causing a computer to operate as the optical path setting device according to any one of claims 1 to 4.

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