Communication path allocation device, communication path allocation method, and program

Abstract

An aspect of the present invention is a communication route allocation device comprising: a route candidate extraction unit which extracts a connectable candidate route on the basis of utilization condition information about a network among optical path routes that connect a start point to an end point of an optical path that accommodates communication demands in the network; a core selection unit which equalizes wavelength utilization conditions of the entire network and selects a core, a link, and an optical path route that accommodate the optical path on the basis of utilization condition information about multi-core fibers of all links in the network or the candidate route; and a wavelength selection unit which selects wavelengths to be used for the core, the link, and the optical path route selected by the route candidate extraction unit and the core selection unit.

Description

[Technical field]

[0001] The present invention relates to a communication path allocation device, a communication path allocation method, and a program technology. [Background technology]

[0002] In response to the increase in traffic, the use of multicore fibers, multimode fibers, few-mode fibers, and multicore-multimode fibers using spatial division multiplexing (SDM) in optical networks is being considered. For example, in a multicore fiber, data can be distributed to multiple cores and transmitted simultaneously. In a multicore fiber, when optical signals with the same spectrum are transmitted via adjacent cores, these signals are strongly affected by inter-core crosstalk. Taking this effect into account, optical path accommodation design technology, which is one technology for controlling a spatial multiplexing optical network system (SDM-NW), is also an important technology for realizing an SDM-NW. For this reason, a core allocation method that takes crosstalk into account using a crosstalk model has been proposed as an optical path accommodation design technology in a multicore fiber (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Shohei Fujii, Yusuke Hirota, “On-Demand Spectrum and Core Allocation for Multi-Core Fibers in Elastic Optical Network”, Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference (OFC / NFOEC), 10.1364 / OFC.2013.OTh4B.4, 2013 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional technology has a problem in that it does not take into consideration the power consumption of a spatial division multiplexing optical amplifier (multi-core optical amplifier), which is one of the elements constituting a spatial division multiplexing optical network system (SDM-NW). In view of the above circumstances, an object of the present invention is to provide a technique capable of reducing the amount of power consumed by spatial multiplexing optical amplifiers (multi-core optical amplifiers) constituting an SDM-NW across the entire network. [Means for solving the problem]

[0005] One aspect of the present invention is a communication path allocation device that includes a route candidate extraction unit that extracts connectable candidate routes from optical path routes connecting start points and end points of optical paths that accommodate communication demand in a network based on usage information of the network, a core selection unit that selects cores, links, and optical path routes that accommodate optical paths by leveling out wavelength usage throughout the network based on usage information of multi-core fibers of all links in the network or the candidate routes, and a wavelength selection unit that selects wavelengths to be used for the cores, links, and optical path routes selected by the route candidate extraction unit and the core selection unit.

[0006] One aspect of the present invention is a communication path allocation method, which extracts connectable candidate routes from optical path routes connecting start points and end points of optical paths that accommodate communication demand in a network based on usage information of the network, selects cores, links, and optical path routes that accommodate the optical paths by leveling out wavelength usage throughout the network based on usage information of multi-core fibers of all links in the network or the candidate routes, and selects wavelengths to use for the selected cores, links, and optical path routes.

[0007] One aspect of the present invention is a program for causing a computer to function as the above-described communication path allocation device. Effect of the Invention

[0008] According to the present invention, it becomes possible to reduce the amount of power consumed by spatially multiplexed optical amplifiers (multi-core optical amplifiers) constituting a spatially multiplexed optical network system (SDM-NW) throughout the entire network. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing an example of the configuration of an SDM optical network equipped with a communication path allocation device of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating an example of the configuration of a multi-core fiber. [Diagram 3] FIG. 1 illustrates an example of a network configuration. [Figure 4] 1 is a diagram for explaining optical path routes, links, cores, and wavelengths. [Diagram 5] 4 is a flowchart of an example of a processing procedure according to the first embodiment. [Figure 6] FIG. 13 is a diagram showing the number of wavelengths in use and the dispersion value on each link based on the core ID and link ID after the optical path n0 is set. [Figure 7] FIG. 2 is a diagram showing the number of wavelengths used in each link L. [Figure 8] 11 is a diagram showing example candidate routes for the optical path n1. FIG. [Figure 9] FIG. 4 is a diagram showing an example of the process of step S2 according to the first embodiment. [Figure 10] 13 is a diagram showing example candidate routes for optical path n2. FIG. [Figure 11] FIG. 11 is a diagram showing an example of the process of step S3 according to the first embodiment. [Figure 12] 13 is a flowchart of an example of a processing procedure according to the second embodiment. [Figure 13] FIG. 11 is a diagram showing an example of the process of step S2A according to the second embodiment. [Figure 14]FIG. 13 is a diagram showing an example of the process of step S3A according to the third embodiment. [Figure 15] 13 is a flowchart of an example of a processing procedure according to the third embodiment. [Figure 16] FIG. 13 is a diagram showing an example of the process of step S2B according to the third embodiment. [Figure 17] FIG. 13 is a diagram showing an example of the process of step S3B according to the third embodiment. [Figure 18] 13 is a flowchart of an example of a processing procedure according to the fourth embodiment. [Figure 19] FIG. 13 is a diagram showing an example of the process of step S2C according to the fourth embodiment. [Figure 20] FIG. 13 is a diagram showing an example of the process of step S3C according to the fourth embodiment. [Figure 21] 13 is a flowchart of an example of a processing procedure according to the fifth embodiment. [Figure 22] FIG. 13 is a diagram illustrating an example of an average value of wavelengths used in the link direction on each core after the optical path n0 is set according to the fifth embodiment. [Diagram 23] FIG. 13 is a diagram showing an example of the process of step S3D according to the fifth embodiment. [Figure 24] 23 is a flowchart of an example of a processing procedure according to the sixth embodiment. [Diagram 25] FIG. 23 is a diagram illustrating an example of an average value of wavelengths used in the link direction on each core after the optical path n0 is set according to the sixth embodiment. [Figure 26] FIG. 23 is a diagram showing an example of the process of step S3E according to the sixth embodiment. [Figure 27] FIG. 13 is a view for explaining a processing method according to a seventh embodiment. [Figure 28] 23 is a flowchart of an example of a processing procedure according to the seventh embodiment. [Figure 29] FIG. 13 is a view for explaining a processing method according to the eighth embodiment. [Diagram 30] 13 is a flowchart of an example of a processing procedure according to the eighth embodiment. [Diagram 31]13 is a diagram for explaining an example of a process for selecting the smallest combination number among combination numbers that satisfy the wavelength continuity constraint and the core continuity constraint and that have no established optical paths, when there is a core continuity constraint; FIG. [Diagram 32] 13 is a diagram for explaining an example of a process for selecting the next combination number having the maximum set optical path number from among combination numbers that satisfy the wavelength continuity constraint and the core continuity constraint when there is a core continuity constraint; FIG. [Diagram 33] 13 is a diagram for explaining an example of a process for selecting the smallest combination number among combination numbers that satisfy the wavelength continuity constraint and the core continuity constraint and that have no established optical paths, without the core continuity constraint. FIG. [Diagram 34] 13 is a diagram for explaining an example of a process for selecting the next combination number having the maximum set optical path number from among combination numbers that satisfy the wavelength continuity constraint and the core continuity constraint when there is a core continuity constraint; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration example of an SDM optical network including a communication path allocation device of the present invention. As shown in FIG. 1, the SDM optical network 100 includes, for example, a communication path allocation device 1, a network operation device 2, and a NW (network) 4. The communication path allocation device 1 includes, for example, an acquisition unit 11, a path candidate extraction unit 12, a core selection unit 13, a wavelength selection unit 14, a storage unit 15, and an output unit 16. The network operation device 2 includes, for example, a wavelength utilization table creation unit 21. The NW 4 includes, for example, multi-core fibers 5 (5-1, 5-2, 5-3, 5-4, 5-5, 5-6, 5-7, 5-8, ...), optical nodes 41 (41-1, 41-2, 41-3, ...), and an optical repeater 42. The optical node 41 includes, for example, an optical transceiver 411, an OXC / OADM 412, and a spatial multiplexing optical amplifier 413. The optical repeater 42 includes, for example, a spatial multiplexing optical amplifier 421. Note that the configuration of the NW 4 shown in FIG. 1 is an example, and the number of the multi-core fibers 5, the optical nodes 41, etc., and the configuration of the optical nodes 41 are not limited to this. Also, the communication path allocation device 1 may be included in the network operation device 2. Note that the communication path allocation device 1 may include the wavelength usage table creation unit 21.

[0011] In the following description, when one of the optical nodes 41-1, 41-2, 41-3, ... is not specified, it is called an optical node 41. When one of the optical transceivers 411-1, 411-2, 411-3, ... is not specified, it is called an optical transceiver 411. When one of the OXC / OADMs 412-1, 412-2, 412-3, ... is not specified, it is called an OXC / OADM 412. When one of the spatial multiplexing optical amplifiers 413-1, 413-2, 413-3, ... is not specified, it is called a spatial multiplexing optical amplifier 413. When one of the multi-core fibers 5-1, 5-2, 5-3, 5-4, 5-5, 5-6, 5-7, 5-8, ... is not specified, it is called a multi-core fiber 5.

[0012] The network operation equipment 2 manages, monitors, and controls each optical node. The network operation equipment 2 creates and manages a wavelength usage table. The wavelength usage table creation unit 21 creates a wavelength usage table based on a core ID (identification information) and a link ID (identification information). More specifically, the wavelength usage table creation unit 21 stores route information (optical path route, link, and core of multi-core fiber) and wavelength information of the optical path to be set (or set), and creates a wavelength usage table.

[0013] The optical node 41 amplifies and performs predetermined processing on the optical signals it transmits and receives. The optical transceiver 411 transmits and receives optical signals via the multi-core fiber 5 . The OXC / OADM 412 has the functions of an OXC (Optical Cross Connect) and an OADM (Optical Add Drop Multiplex).

[0014] The spatial multiplexing optical amplifier (413 or 421) is a multi-core optical amplifier. The spatial multiplexing optical amplifier (413 or 421) includes a cladding pumping laser that collectively pumps all the cores of the multi-core fiber 5, and may also include both a cladding pumping laser and a core pumping laser that individually pumps each core. The spatial multiplexing optical amplifier (413 or 421) amplifies an optical signal to be transmitted in accordance with the number of wavelengths (number of optical paths) accommodated in each core of the multi-core fiber 5, based on information (optical path route, link, core, wavelength) output by the communication path allocation device 1.

[0015] The communication path allocation device 1 uses the wavelength utilization table created by the network operation device 2, taking into consideration the power saving characteristics of the multi-core optical amplifiers that make up the SDM-NW, and determines the optical path route, link, core, and wavelength in the optical path design when an optical path connection request is made so that the number of wavelengths set in the cores to be used is equalized.

[0016] The acquiring unit 11 acquires a wavelength usage table based on the core ID and the link ID from the network operation device 2, and stores in the storage unit 15 the wavelength usage table based on the acquired core ID and the link ID.

[0017] The route candidate extraction unit 12 extracts connectable route candidates from among optical path routes connecting the start point and the end point of an optical path that accommodates a certain communication demand in the NW (network) 3 based on network usage information. More specifically, the route candidate extraction unit 12 selects an optical path route in which the same wavelength can be used in all links and cores that constitute the route candidate (satisfying the wavelength continuity constraint) from among the candidate routes based on the network usage information by a well-known method. Furthermore, the route candidate extraction unit 12 calculates, as an optical path route, a route in which the same core can be used in all links that constitute the route candidate (satisfying the core continuity constraint) or a route in which the same core is not used in all links that constitute the route candidate (not dependent on the core continuity constraint). When the core continuity constraint is applied, the route candidate extraction unit 12 calculates an optical path route in which the same core can be used in all links that constitute the route candidate, and when the core continuity constraint is not applied, calculates, as an optical path route, a route that is a combination of all links that constitute the route candidate and all of their cores.

[0018] The core selection unit 13 determines the cores and links that accommodate the optical paths so as to level the wavelength usage status of the entire network based on the usage status information of the multi-core fibers 5 of all links in the network or the route candidate, and determines the optical path route. Note that the processing performed by the core selection unit 13 will be described in each embodiment.

[0019] The wavelength selection unit 14 determines the wavelengths to be used for the optical path routes calculated by the route candidate extraction unit 12 and the core selection unit 13. More specifically, the wavelength selection unit 14 selects the wavelengths that maximize the wavelength utilization efficiency of the entire network from among the candidate routes calculated by a well-known method, based on the network usage status information.

[0020] The storage unit 15 stores the information acquired by the acquisition unit 11 and the information extracted, calculated, or selected by each of the route candidate extraction unit 12, the core selection unit 13, and the wavelength selection unit 14. The storage unit 15 stores expressions used by each of the route candidate extraction unit 12, the core selection unit 13, and the wavelength selection unit 14 for extraction, calculation, or selection.

[0021] The output unit 16 outputs information relating to the optical path route, link, and core determined by the core selection unit 13 and the wavelength determined by the wavelength selection unit 14 to the spatial multiplexing optical amplifier (413 or 421) via the network operation equipment 2 and the optical node 41.

[0022] The communication path allocation device 1 is configured using a processor such as a CPU (Central Processing Unit) and a memory. The communication path allocation device 1 functions as, for example, an acquisition unit 11, a path candidate extraction unit 12, a core selection unit 13, a wavelength selection unit 14, and an output unit 16 by the processor executing a program. All or part of the functions of the communication path allocation device 1 may be realized using hardware such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array). The above program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a semiconductor storage device (for example, an SSD: Solid State Drive), or a storage device such as a hard disk or a semiconductor storage device built into a computer system. The above program may be transmitted via an electric communication line or an optical communication line.

[0023] FIG. 2 is a diagram showing a configuration example of a multicore fiber. The multicore fiber 500 shown in FIG. 2 includes seven cores F1 to F7 in one cladding. In FIG. 2, the central core F4 is a first core group, and the other cores F1 to F3 and F5 to F7 are a second core group. The core group is a group of cores having the same transmission quality (see, for example, Japanese Patent No. 6663384). In the following embodiments, the multicore fiber 500 of the configuration example in FIG. 2 will be described as an example, but the number of cores included in the multicore fiber may be six or less, or eight or more. In addition, it is not necessary to group each core of the multicore fiber into a core group. In addition, the multicore fiber may be a transmission line optical fiber capable of spatially separating signals, such as a multimode fiber, a few-mode fiber, or a multicore-multimode fiber.

[0024] FIG. 3 is a diagram showing an example of a network configuration. The network shown in FIG. 3 has a 3×3 lattice configuration. In FIG. 3, links L1 to L12 are edges (branches, sides) of the network in graph theory. Numbers 0 to 8 are nodes (vertices, contact points) of the network in graph theory. In the following embodiments, the network shown in FIG. 3 will be used as an example for explanation, but the network configuration is not limited to this. Furthermore, such a network configuration is created and stored, for example, by network operation device 2.

[0025] Here, the optical path route, the link, the core, and the wavelength in the embodiment will be described with reference to FIG. 4. FIG. 4 is a diagram for explaining the optical path route, the link, the core, and the wavelength. In the example of FIG. 4, among the nodes N1 to N6, the node N1 is the starting point of the optical path that accommodates the communication demand in the network, and the node N6 is the end point of the communication demand in the network. The nodes are connected by a multi-core fiber 5 that connects the nodes. In addition, there may be a plurality of links L that connect the nodes. For example, there is one link (link L1) between the node N1 and the node N2, and there are two links (links L2, L3) between the node N2 and the node N3. In each embodiment, the link L is a multi-core fiber 5. And, the multi-core fiber 5 used for the link L has a plurality of cores F as shown in FIG. 2. Furthermore, there are wavelengths in the cores. For example, in the case of a WDM (Wavelength Division Multiplexing) system, there are a plurality of wavelengths. For this reason, in the embodiment, the optical path route, the link, the core, and the wavelength are selected (determined) in order to set up the optical path.

[0026] In FIG. 4, four candidates for the optical path route (first candidate route to fourth candidate route) are illustrated. The first candidate route is route R1, which is a route from link L1 to link L2 to link L6. The second candidate route is route R1, which is a route from link L1 to link L3 to link L6. Route R1 is a route in the order of nodes N1 to N2 to N3 to N6. The third candidate route is route R2, which is a route from link L4 to link L7 to link L9. The fourth candidate route is route R1, which is a route from link L1 to link L8 to link L9. Route R2 is a route in the order of nodes N1 to N4 to N5 to N6.

[0027] Furthermore, the first to fourth candidate routes are further divided according to the cores and wavelengths used. In each method of the embodiment, under wavelength continuity constraint, if "core continuity constraint is applied", the same core number is used for each link of link xyz, and the empty wavelengths in those cores are candidates. Also, in each method of the embodiment, under wavelength continuity constraint, if "core continuity constraint is not applied", each link of link xyz may have a different core number, and the empty wavelengths in those cores are candidates.

[0028] Here, the space division multiplexing optical amplification technology will be explained (see, for example, Reference 1). Space division multiplexing optical amplification technologies are roughly classified into two types. One is the multi-core erbium-doped fiber amplifier (MC-EDFA), which uses an MCF-type amplification medium with multiple erbium-doped cores in a single optical fiber. The other is the few-mode erbium-doped fiber amplifier (FM-EDFA), which uses a few-mode fiber (FMF)-type amplification medium that limits the higher-order modes excited by a type of multimode fiber.

[0029] Reference 1: Hirotaka Ono, "Space Division Multiplexing Optical Amplification Base Technology", NTT Technical Journal, March 2017, p23-27

[0030] In the following embodiments, the present invention is applied to, for example, an MC-EDFA. The pumping method of the MC-EDFA is classified into core pumping, which pumps each core individually to input pumping light and signal light to the core, and cladding pumping, which pumps all cores at once. The core pumping laser has a characteristic of consuming more power than the cladding pumping laser. In contrast, the MC-EDFA can save power by using both core pumping and cladding pumping (hybrid pumping, etc.). Therefore, in the following embodiments, the number of wavelengths allocated to each core is leveled and the proportion of cladding pumping is increased to increase the power saving effect. From the viewpoint of network design, in order to maximize the advantage of this power saving effect, cooperation with the optical path accommodation design is essential. Therefore, in the following embodiments, the number of wavelengths allocated to each core on the MC-EDFA is leveled by the optical path accommodation design. More specifically, in order to perform wavelength allocation taking into account the power saving effect of the MC-EDFA, in the following embodiments, the dispersion value (or standard deviation value) or average value of the number of wavelengths is used as a metric to level the number of wavelengths used for wavelength allocation.

[0031] First Embodiment In this embodiment, in a spatial multiplexing optical network system, the dispersion value (variation) or standard deviation of the number of wavelengths used for each core of a multicore fiber 5 (MCF) throughout the NW 4 is used as an index to select cores within the same core group (with core continuity constraint (use of the same core) and wavelength continuity constraint). In this embodiment, the metric is calculated for the entire NW (network), the metric is calculated as the dispersion value or standard deviation, and there is a core continuity constraint. In the following explanation, the multicore fiber configuration shown in FIG. 2, the network configuration shown in FIG. 3, and the dispersion value are used for metric calculation as examples.

[0032] FIG. 5 is a flowchart of an example of a processing procedure according to this embodiment. (Step S1) The communication path allocation device 1 calculates the dispersion value V on each link after the optical path n0 is set, using the following formula (1).

[0033]

number

[0034] In formula (1), n ​​is the number of cores, i is the core ID (identification information), and x i is the number of wavelengths used by the core Fi, and x is x i The value calculated by the communication path allocation device 1 is not limited to the variance of the number of wavelengths used, but may be the standard deviation of the number of wavelengths used.

[0035] (Step S2) The communication path allocation device 1 calculates a metric for setting the optical path n1. The process performed in step S2 will be described later.

[0036] (Step S3) The communication path allocation device 1 calculates a metric for setting the optical path n2. The process performed in step S3 will be described later.

[0037] FIG. 6 is a diagram showing the number of wavelengths used and the dispersion value on each link based on the core ID and link ID after the optical path n0 is set. In the following description, the dispersion value of the number of wavelengths used in the links L1 to L12 is V L1 ~V L12 6, the value of each square indicates the number of wavelengths in use, and for example, the number of wavelengths in use of core ID F1 in link L1 is 5. The communication path allocation device 1 obtains or refers to the wavelength usage table excluding the dispersion value from the network operation device 2.

[0038] 7 is a diagram showing an example of the number of wavelengths used in each core in each link L. The numbers of wavelengths used in cores F1 to F7 in the first link (link L1) g101 are 5, 1, 6, 1, 2, 5, and 4. The numbers of wavelengths used in cores F1 to F7 in the second link (link L2) g102 are 6, 2, 4, 1, 3, 0, and 1.

[0039] Next, the process of step S2 for calculating an index (metric) for setting the optical path n1 {(A,Z)=(0,8)} will be described. FIG. 8 is a diagram showing an example of a candidate route for the optical path n1. FIG. 9 is a diagram showing an example of the process of step S2 according to this embodiment. Note that the metric V in FIG. nw,j The reason why core F4 is blank in the table is because core F4 is in the first core group and is not used in the second core group.

[0040] (Step S21) The route candidate extraction unit 12 finds the shortest route by, for example, Dijkstra's algorithm, and calculates and extracts a candidate route for the optical path n1 that satisfies the wavelength continuity constraint. In the following explanation, a case where link L1-link L2-link L5-link L10 is calculated as the candidate route for the optical path n1 as shown in FIG. 8 will be explained.

[0041] (Step S22) The core selection unit 13 sets the optical path n1 to be used for the second core group.

[0042] (Step S23) The core selection unit 13 selects the core F1 and calculates the number of links (L j ) variance value V Lj and metric V nw,j (=1 / j×Σ(V Lj ) (the variance of the entire NW4). Note that the metric V nw,j Then, the sum of the variance values ​​for all links in the network (Σ(V Lj )) is calculated. Therefore, the metric V nw,j The number of j does not change for any candidate route (assuming the total number of links in the network does not change). As a concrete example, the sum of the variance values ​​is Σ(V Lj )=V L1 +V L2 +V L3 +V L4 +V L5 +V L6 +V L7 +V L8 +V L9 +V L10+V L11 +V L12 (j=1 to 12). The core selection unit 13 calculates the dispersion value V Lj and metric V nw,j ("metric calculation F2" in FIG. 9). Next, the core selection unit 13 calculates the dispersion value V Lj and metric V nw,j Next, the core selection unit 13 calculates the dispersion value V Lj and metric V nw,j Next, the core selection unit 13 calculates the dispersion value V Lj and metric V nw,j Next, the core selection unit 13 calculates the dispersion value V Lj and metric V nw,j In this embodiment, since the cores in the same core group are selected as described above, the optical path n1 calculates the metric V nw,j In the following embodiments, the metrics are calculated for the cores in the selected core group in the same manner as in the first embodiment when the first core group is selected.

[0043] (Step S25) The core selection unit 13 selects the metric V nw,j The core F with the smallest is selected as the utilized core for the optical path n1.

[0044] (Step S26) The wavelength selection unit 14 selects a wavelength in the selected core using a wavelength selection algorithm such as the least fragmentation (LF) method (see Reference 2) or the first fit (FF) method (see Reference 3). The LF method and the FF method are wavelength selection algorithms (wavelength selection methods) in optical path accommodation design. When there are multiple wavelengths that can be assigned end-to-end when selecting the wavelength of an optical signal on a communication path, that is, when there are multiple wavelengths that satisfy the wavelength continuity constraint, the LF method is an algorithm that preferentially uses wavelengths that suppress the occurrence of sections in which the wavelength usage status is fragmented for each communication path section by calculating the correlation amount between the wavelength usage status of each link on the communication path and the wavelength usage status of an adjacent link, and the FF method is an algorithm that assigns wavelengths in order from the smallest number to the number given to the wavelengths.

[0045] Reference 2; Yoshiaki Sone, et al., “Efficient Routing and Wavelength Assignment “Algorithm Minimizes Wavelength Fragmentations in WDM Mesh Networks”, OECC2011,p178-p179, 6A1_4, Jul. 2011 Reference 3;HUI Zang, et al., “A Review of Routing and Wavelength Assignment Approaches for Wavelength-Routed Optical WDM Networks”, Optical Network Magazine, Vol.1, pp.47-60, Jan. 2000

[0046] 9, the initial state is (L1, L2, L5, L10) = (5, 6, 7, 2) @ F1, (L1, L2, L5, L10) = (1, 2, 1, 2) @ F2, .... In step S23, the core selection unit 13 calculates the metric F1 by setting (L1, L2, L5, L10) = (6, 7, 8, 3) @ F1, and obtains the metric Vnw,j In addition, the core selection unit 13 calculates the metric V nw,j In step S25, the core selection unit 13 calculates the metric V nw,j Select the core F2, which has the minimum value of 6.071.

[0047] Next, the process of step S3 for calculating an index (metric) for setting the optical path n2 {(A,Z)=(0,7)} will be described. FIG. 10 is a diagram showing an example of a candidate route for the optical path n2. FIG. 11 is a diagram showing an example of the process of step S3 according to this embodiment. Note that the metric V in FIG. nw,j The reason why core F4 is blank in the table is because core F4 is in the first core group and is not used in the second core group.

[0048] (Step S31) The route candidate extraction unit 12 extracts candidate routes for the optical path n2 by, for example, calculating using the Dijkstra algorithm. In the following description, a case will be described in which a first candidate route (link L1-link L4-link L9) and a second candidate route (link L3-link L8-link L11) are calculated as candidate routes for the optical path n2, as shown in FIG. 10.

[0049] (Step S32) The core selection unit 13 sets the optical path n2 to be used for the second core group.

[0050] (Step S33) The core selection unit 13 selects the core F1 and uses a wavelength on the candidate route. j ) variance value V Lj and metric V nw,j (=1 / j×Σ(V Lj The core selection unit 13 calculates the dispersion value V Lj and metric V nw,jNext, the core selection unit 13 calculates the dispersion value V Lj and metric V nw,j Next, the core selection unit 13 calculates the dispersion value V Lj and metric V nw,j Next, the core selection unit 13 calculates the dispersion value V Lj and metric V nw,j Next, the core selection unit 13 calculates the dispersion value V Lj and metric V nw,j is calculated for each candidate route.

[0051] (Step S35) The core selection unit 13 selects the metric V nw,j The candidate route and core F with the smallest are selected as the route, link, and core to be used for the optical path n2.

[0052] (Step S36) The wavelength selection unit 14 selects a wavelength within the selected core by using, for example, the LF method or the FF method.

[0053] 11, the initial state is (L1, L4, L9) = (5, 6, 4) @ F1, (L1, L4, L9) = (1, 2, 8) @ F2, .... In step S33, the core selection unit 13 calculates the metric F1 of the first candidate route as (L1, L4, L9) = (6, 7, 5) @ F1, and obtains the metric V nw In addition, in step S34, the core selection unit 13 calculates the metric F2 of the first candidate route by setting (L1, L4, L9) = . nw Furthermore, the core selection unit 13 performs metric calculation F1 of the second candidate route in step S33, and performs metric calculations F2 to F7 of the second candidate route in step S34. Then, the core selection unit 13 calculates the metric V nw,jSelect the second candidate path and core F1, which has the minimum value of 5.983.

[0054] Through the above process, the core selection unit 13 selects, for example, the route link L1-L2-L5-L10 and the core F2 as the optical path n1, and the route link L3-L8-L11 and the core F1 as the optical path n2.

[0055] As described above, in this embodiment, the number of wavelengths (number of optical paths) accommodated in each core is controlled by extracting and selecting the optical path route, the link, the core, and the wavelength to be used, using the variance value or the standard deviation of the wavelength usage status of the entire NW4 with the core continuity constraint. As a result, according to this embodiment, the power saving characteristics of the multi-core optical amplifier constituting the SDM-NW are taken into consideration, and the number of wavelengths set in the cores to be used can be equalized in the optical path design when an optical path connection is requested. As a result, according to this embodiment, the number of wavelengths used in each core can be equalized, and the effect of reducing the power consumption of the multi-core optical amplifier can be obtained throughout the entire network.

[0056] In the above example, the cores are divided into the first core group and the second core group and then allocated, but this is not limiting. The core selection unit 13 may select all cores in steps S2 and S3.

[0057] Here, a processing example in which all cores are selected will be described. The route candidate extraction unit 12 extracts candidate routes for the optical path n1 by, for example, calculating them using the Dijkstra algorithm (step S21). After the process, the route candidate extraction unit 12 proceeds to the process of step S23.

[0058] The core selection unit 13 selects the cores F1 to F7 and calculates the number of links (L j ) variance value V Lj and metric V nw,j (=1 / j×Σ(V Lj ) (the variance value of the entire NW4) is calculated (step S23).

[0059] The core selection unit 13 selects the metric V nw,j The core F having the smallest λ is selected as the utilized core for the optical path n1 (step S25). The wavelength selection unit 14 selects a wavelength in the selected core by using, for example, the LF method or the FF method (step S26).

[0060] In the example of FIG. 9 where all cores are selected, the core selection unit 13 performs metric calculation F1 as follows in step S23: (L1, L2, L5, L10)=(6, 7, 8, 3)@F1 to obtain the metric V nw,j Calculate the metric F2 as (L1, L2, L5, L10) = (2, 3, 2, 3) @ F2 and calculate the metric V nw,j Calculate the metric F3 as (L1, L2, L5, L10) = (7, 5, 3, 4) @ F3 and calculate the metric V nw,j Calculate the metric F4 as (L1, L2, L5, L10) = (2, 2, 9, 7) @ F4 and calculate the metric V nw,j Then, in step S25, the core selection unit 13 calculates the metric V nw,j Select the core for which is smallest.

[0061] That is, if all cores are selected, the process relating to the core group in step S22 is not performed, and metric calculation is also performed for core F4, which is in the first core group, so that all cores are included. Although the seven-core fiber shown in the example has two core groups, the same process can be applied to a multi-core fiber having more core groups.

[0062] <Second embodiment> In this embodiment, in a spatial multiplexing optical network system, the dispersion value (variation) of the entire NW4 of the number of wavelengths used for each core is used as the metric, and cores in the same core group are selected (conditions without core continuity constraints, in which the same cores do not have to be used, and conditions with wavelength continuity constraints). In this embodiment, the metric is calculated for the entire NW (network), the metric is calculated as the dispersion value or standard deviation, and there is no core continuity constraint. In the following explanation, the multi-core fiber configuration shown in FIG. 2 and the network configuration shown in FIG. 3 are used as examples. In this embodiment, either the dispersion value or the standard deviation may be used for the metric calculation. In the following example, the case where the dispersion value is used is explained.

[0063] FIG. 12 is a flowchart of an example of a processing procedure according to this embodiment. (Step S1) The communication path allocation device 1 calculates the dispersion value V on each link after the optical path n0 is set, using equation (1).

[0064] (Step S2A) The communication path allocation device 1 calculates a metric for setting the optical path n1. The process performed in step S2A will be described later.

[0065] (Step S3A) The communication path allocation device 1 calculates a metric for setting the optical path n2. The process performed in step S3A will be described later.

[0066] Next, the process of step S2A for calculating an index (metric) for setting the optical path n1{(A,Z)=(0,8)} will be described. Fig. 13 is a diagram showing an example of the process of step S2A according to this embodiment.

[0067] (Step S21) The route candidate extraction unit 12 extracts candidate routes for the optical path n1 by calculating, for example, the Dijkstra algorithm. In the following explanation, a case where link L1-link L2-link L5-link L10 is calculated as the candidate route for the optical path n1 as shown in Fig. 8 will be explained. (Step S22) The core selection unit 13 sets the optical path n1 to be used for the second core group.

[0068] (Step S23A) The core selection unit 13 selects the core combination (Fj, Fj, Fj, Fj) of the optical path n1 and calculates the number of links (L j ) variance value V Lj and metric V nw,j (Dispersion value of entire NW4) is calculated. Note that the combination of cores is as shown in FIG. 13: core (F1, F1, F1, F1), core (F1, F2, F1, F1), core (F1, F2, F2, F1), ... core (F7, F7, F7, F7).

[0069] (Step S25) The core selection unit 13 selects the metric V nw,j The core F having the smallest λ is selected as the core to be used for the optical path n1. (Step S26) The wavelength selection unit 14 selects a wavelength in the selected core by using, for example, the LF method or the FF method.

[0070] Next, a process of step S3A for calculating an index (metric) for setting the optical path n2{(A,Z)=(0,7)} will be described. Fig. 14 is a diagram showing an example of the process of step S3A according to this embodiment.

[0071] (Step S31) The route candidate extraction unit 12 extracts candidate routes for the optical path n2 by calculating, for example, the Dijkstra algorithm. In the following explanation, a case will be explained in which a first candidate route (link L1-link L4-link L9) and a second candidate route (link L3-link L8-link L11) are calculated as candidate routes for the optical path n2, as shown in Fig. 10. (Step S32) The core selection unit 13 sets the optical path n2 to be used in the second core group.

[0072] (Step S33A) The core selection unit 13 selects the core combination (Fj, Fj, Fj, Fj) of the optical path n1 and calculates the number of links (L j ) variance value V Lj and metric V nw,j(The variance value of the entire NW4) is calculated for each candidate route. Note that the combination of cores is as shown in FIG. 14: core (F1, F1, F1), core (F1, F2, F1), core (F1, F2, F2), ... core (F7, F7, F7).

[0073] (Step S35) The core selection unit 13 selects the metric V nw,j The candidate route and core F with the smallest φ are selected as the route to be used and the core to be used for the optical path n2. (Step S36) The wavelength selector 14 selects a wavelength in the selected core by using, for example, the LF method or the FF method.

[0074] The difference between the first and second embodiments is that the first embodiment has a core continuity constraint that selects cores with the same core number for each link constituting an optical path route, while the second embodiment has no core continuity constraint. In this embodiment, when there is no core continuity constraint, the condition is that "the same core does not have to be used," so "metric calculation 2; (L1, L2, L5, L10) @ (F1, F2, F1, F1) = (6, 3, 8, 3) in Figure 13 is used to calculate V nw The calculation process that includes different core numbers on the candidate routes after "Calculate L1, L2, L5, L10" differs from the first embodiment. In this embodiment, metrics are calculated for all possible combinations of cores for each link on the route (L1, L2, L5, L10). In contrast, in the first embodiment, metrics are calculated for only combinations of the same core for each link on the route.

[0075] As described above, in this embodiment, the number of wavelengths (number of optical paths) accommodated in each core is controlled by extracting and selecting the optical path route, the cores to be used, and the wavelengths without core continuity constraints, using the variance value or standard deviation of the wavelength usage status of the entire NW4. As a result, according to this embodiment, the number of wavelengths used in each core can be leveled, and the effect of reducing the power consumption of multi-core optical amplifiers can be obtained throughout the entire network.

[0076] In the above example, the core selection unit 13 may select all of the cores in steps S2A and S3A.

[0077] <Third embodiment> In the first and second embodiments, the variance (or standard deviation) of the entire NW4 (V nw,j ) was used, but in this embodiment, the variance (or standard deviation) on the candidate route (V cr,k ) is used (conditions with core continuity constraint of using the same core and with wavelength continuity constraint). In this embodiment, the metric is calculated for candidate routes, the metric is calculated as a dispersion value or standard deviation, and there is a core continuity constraint. In the following explanation, the multi-core fiber configuration shown in FIG. 2 and the network configuration shown in FIG. 3 are used as examples. In this embodiment, either the dispersion value or the standard deviation may be used for the metric calculation. In the following example, a case where the dispersion value is used is explained.

[0078] FIG. 15 is a flowchart of an example of a processing procedure according to this embodiment. (Step S1) The communication path allocation device 1 calculates the dispersion value V on each link after the optical path n0 is set, using equation (1).

[0079] (Step S2B) The communication path allocation device 1 calculates a metric for setting the optical path n1. When setting the optical path n1, the communication path allocation device 1 uses the variance value on the candidate route for metric calculation. The process performed in step S2B will be described later.

[0080] (Step S3B) The communication path allocation device 1 calculates a metric for setting the optical path n2. The process performed in step S3B will be described later.

[0081] Next, the process of step S2B for calculating an index (metric) for setting the optical path n1{(A,Z)=(0,8)} will be described. FIG. 16 is a diagram showing an example of the process of step S2B according to this embodiment. Note that the metric V in FIG. cr,k The reason why core F4 is blank in the table is because core F4 is in the first core group and is not used in the second core group.

[0082] (Step S21) The route candidate extraction unit 12 extracts candidate routes for the optical path n1 by calculating, for example, the Dijkstra algorithm. In the following explanation, a case will be explained in which the candidate route for the optical path n1 is calculated as link L1-link L2-link L5-link L10 as shown in Fig. 8. (Step S22) The core selection unit 13 sets the optical path n1 to be used for the second core group.

[0083] (Step S23B) The core selection unit 13 selects the core F1 and calculates the number of links (L k ) variance value V Lk and metric V cr,k (=1 / k×Σ(V Lk In this way, in this embodiment, the metric V cr,k Calculate the metric V cr,k is the sum of the variances of only the links on the candidate route (Σ(V Lk )) is calculated. Also, the metric V cr,k The number of k changes for each candidate route (depending on the number of links in the candidate route). As a specific example, the sum of the variance values ​​in the case of Figure 8 is Σ(V Lk )=V L1 +V L2 +V L5 +V L10 (k=1, 2, 5, 10). The core selection unit 13 calculates the dispersion value V Lk and metric V cr,k Next, the core selection unit 13 calculates the dispersion value V Lk and metric V cr,k Next, the core selection unit 13 calculates the dispersion value V Lk and metric V cr,k Next, the core selection unit 13 calculates the dispersion value VLk and metric V cr,k Next, the core selection unit 13 calculates the dispersion value V Lk and metric V cr,k Calculate.

[0084] (Step S25) The core selection unit 13 selects the metric V cr,k The core F having the smallest λ is selected as the core to be used for the optical path n1. (Step S26) The wavelength selection unit 14 selects a wavelength in the selected core by using, for example, the LF method or the FF method.

[0085] For example, in the example of FIG. 16, the core selection unit 13 performs the metric calculation F1 in step S23B by setting (L1, L2, L5, L10)=(6, 7, 8, 3)@F1 to obtain the metric V cr,k In addition, the core selection unit 13 calculates the metric V cr,k In step S25, the core selection unit 13 calculates the metric V cr,k Select the core F2 with the minimum value of 4.653.

[0086] Next, the process of step S3B for calculating an index (metric) for setting optical path n2 {(A,Z)=(0,7)} will be described. FIG. 17 is a diagram showing an example of the process of step S3B according to this embodiment. In FIG. 17, table g201 is a wavelength utilization table and dispersion value based on core IDs and link IDs when a first candidate route for optical path n2 is calculated. Table g202 is a wavelength utilization table and dispersion value based on core IDs and link IDs when a second candidate route for optical path n2 is calculated. Note that the metric V in FIG. 17 cr,k The reason why core F4 is blank in the table is because core F4 is in the first core group and is not used in the second core group.

[0087] (Step S31) The route candidate extraction unit 12 extracts candidate routes for the optical path n2 by calculating, for example, the Dijkstra algorithm. In the following explanation, a case will be explained in which a first candidate route (link L1-link L4-link L9) and a second candidate route (link L3-link L8-link L11) are calculated as candidate routes for the optical path n2, as shown in Fig. 10. (Step S32) The core selection unit 13 sets the optical path n2 to be used in the second core group.

[0088] (Step S33B) The core selection unit 13 selects the core F1 and calculates the number of links (L k ) variance value V Lk and metric V cr,k (=1 / k×Σ(V Lk )) is calculated for each candidate route. As a specific example, the sum of the variance values ​​of the first candidate route in FIG. Lk )=V L1 +V L4 +V L9 (k=1,4,9), and the sum of the variance values ​​of the second candidate route is Σ(V Lk )=V L3 +V L8 +V L11 (k=3, 8, 11). The core selection unit 13 calculates the dispersion value V Lk and metric V cr,k Next, the core selection unit 13 calculates the dispersion value V Lk and metric V cr,k Next, the core selection unit 13 calculates the dispersion value V Lk and metric V cr,k Next, the core selection unit 13 calculates the dispersion value V Lk and metric V cr,kNext, the core selection unit 13 calculates the dispersion value V Lk and metric V cr,k is calculated for each candidate route.

[0089] (Step S35B) The core selection unit 13 selects the metric V cr,k The candidate route and core F with the smallest Δt are selected as the optical path route, link to be used, and core to be used for the optical path n2. (Step S36) The wavelength selection unit 14 selects a wavelength within the selected core using, for example, the LF method or the FF method.

[0090] For example, in the example of FIG. 17, the core selection unit 13 selects the metric V cr,k Select the second candidate path and core F1, which has the minimum value of 5.850.

[0091] As described above, in this embodiment, with the core continuity constraint, the number of wavelengths (number of optical paths) accommodated in each core is controlled by extracting and selecting the optical path route, the cores to be used, and the wavelengths using the variance value or standard deviation of the wavelength usage status on the candidate route. As a result, according to this embodiment, the number of wavelengths used in each core can be leveled, and the effect of reducing the power consumption of multi-core optical amplifiers can be obtained throughout the entire network.

[0092] In the above example, the core selection unit 13 may select all of the cores in steps S2B and S3B.

[0093] <Fourth embodiment> In this embodiment, the dispersion value or standard deviation of the wavelength usage status on the candidate route is used (conditions without core continuity constraint, with wavelength continuity constraint). In this embodiment, the metric is calculated for the candidate route, the metric is calculated as the dispersion value or standard deviation, and there is no core continuity constraint. In the following explanation, the multi-core fiber configuration shown in FIG. 2 and the network configuration shown in FIG. 3 are used as examples. In this embodiment, either the dispersion value or the standard deviation may be used for the metric calculation. In the following example, the case where the dispersion value is used is explained.

[0094] FIG. 18 is a flowchart of an example of a processing procedure according to this embodiment. (Step S1) The communication path allocation device 1 calculates the dispersion value V on each link after the optical path n0 is set, using equation (1).

[0095] (Step S2C) The communication path allocation device 1 calculates a metric for setting the optical path n1. When setting the optical path n1, the communication path allocation device 1 uses the variance value on the candidate route for metric calculation. The process performed in step S2C will be described later.

[0096] (Step S3C) The communication path allocation device 1 calculates a metric for setting the optical path n2. Note that the process performed in step S3C will be described later.

[0097] Next, the process of step S2C for calculating an index (metric) for setting optical path n1{(A,Z)=(0,8)} will be described. Fig. 19 is a diagram showing an example of the process of step S2C according to this embodiment. Note that the reason why core F4 is blank in the metric table in Fig. 19 is that core F4 is in the first core group and is not used in the second core group.

[0098] (Step S21) The route candidate extraction unit 12 extracts candidate routes for the optical path n1 by, for example, calculating using the Dijkstra algorithm. In the following explanation, a case where link L1-link L2-link L5-link L10 is calculated as the candidate route for the optical path n1 as shown in Fig. 8 will be explained as an example. (Step S22) The core selection unit 13 sets the optical path n1 to be used for the second core group.

[0099] (Step S23C) The core selection unit 13 selects the core F1 and calculates the number of links (L k ) variance value V Lk The core selection unit 13 calculates the link (L k ) variance value V Lk Next, the core selection unit 13 calculates the link (L k ) variance value V Lk Next, the core selection unit 13 calculates the link (L k ) variance value V Lk Next, the core selection unit 13 calculates the link (L k ) variance value V Lk Next, the core selection unit 13 calculates the link (L k ) variance value V Lk Next, the core selection unit 13 calculates the link (L k ) variance value V Lk Calculate.

[0100] (Step S24C) The core selection unit 13 calculates the variance value V L1,fFor example, the core selection unit 13 calculates the minimum value of the variance value V L1,f Next, the core selection unit 13 calculates the minimum value of the variance value V L1,f Next, the core selection unit 13 calculates the minimum value of the variance value V L1,f Next, the core selection unit 13 calculates the minimum value of the variance value V L1,f Calculate the minimum value of .

[0101] (Step S25C) The core selection unit 13 calculates the average value V cl,q (=1 / q×Σ(V L1,f ;min) is calculated as the metric. Note that when the candidate route is link L1-link L2-link L5-link L10, q is 4.

[0102] (Step S26C) The core selection unit 13 selects the metric V cl,q The core F having the smallest λ is selected as the utilized core for the optical path n1. (Step S27C) The wavelength selection unit 14 selects a wavelength in the selected core by using, for example, the LF method or the FF method.

[0103] As shown in FIG. 19, the initial state of the metric calculation is (F1, F2, ..., F7)@L1=(5, 1, ..., 4), @L2=.... In the first metric calculation, the variance value is calculated as (F1, F2, ..., F7)@L1=(6, 1, ..., 4). In the second metric calculation, the variance value is calculated as (F1, F2, ..., F7)@L1=(5, 2, ..., 4). In the xth metric calculation, the variance value is calculated as (F1, F2, ..., F7)@L1=(5, 1, ..., 5). Then, the core selection unit 13 selects the core with the smallest variance value among the first to xth metric calculations. In the above-mentioned candidate route (L1, L2, L5, L10), the metric is V cl,q = 4.439, and the selected path is (F2, F6, F2, F5), which is the minimum of (L1, L2, L5, L10) respectively, as shown in FIG. 19.

[0104] Next, the process of step S3C for calculating an index (metric) for setting the optical path n2{(A,Z)=(0,7)} will be described. Fig. 20 is a diagram showing an example of the process of step S3C according to this embodiment. Note that the reason why core F4 is blank in the metric table in Fig. 20 is that core F4 is in the first core group and is not used in the second core group.

[0105] (Step S31) The route candidate extraction unit 12 extracts candidate routes for the optical path n2 by calculating, for example, the Dijkstra algorithm. In the following explanation, a case will be explained in which a first candidate route (link L1-link L4-link L9) and a second candidate route (link L3-link L8-link L11) are calculated as candidate routes for the optical path n2, as shown in FIG. 10. (Step S32) The core selection unit 13 sets the optical path n2 to be used in the second core group.

[0106] (Step S33C) The core selection unit 13 selects the core F1 and calculates the number of links (L k ) variance value V Lk The core selection unit 13 calculates the link (L k ) variance value V Lk Next, the core selection unit 13 calculates the link (L k ) variance value V Lk Next, the core selection unit 13 calculates the link (L k ) variance value V Lk Next, the core selection unit 13 calculates the link (L k ) variance value V LkNext, the core selection unit 13 calculates the link (L k ) variance value V Lk Next, the core selection unit 13 calculates the link (L k ) variance value V Lk is calculated for each candidate route.

[0107] (Step S34C) The core selection unit 13 selects the variance value V L1,f For example, in the first candidate route of the optical path n2, the core selection unit 13 calculates the minimum value of the variance value V L1,f Next, the core selection unit 13 calculates the minimum value of the variance value V L1,f Next, the core selection unit 13 calculates the minimum value of the variance value V L1,f Similarly, for the second candidate route of the optical path n2, the core selection unit 13 calculates the minimum value of the variance value V L1,f Next, the core selection unit 13 calculates the minimum value of the variance value V L1,f Next, the core selection unit 13 calculates the minimum value of the variance value V L1,f The minimum value of is calculated for each candidate route.

[0108] (Step S35C) The core selection unit 13 calculates a metric V cl,q (Step S36C) The core selection unit 13 calculates the metric V cl,q Of these, metric V cl,qThe candidate route and core F for which the ratio is smallest are selected as the route to be used and the core to be used for the optical path n2. (Step S37C) The wavelength selector 14 selects a wavelength in the selected core by using, for example, the LF method or the FF method.

[0109] For example, as shown in FIG. 20, the calculation result of the dispersion value of the first candidate route of the lightpath n2 is shown in table g251, and the calculation result of the dispersion value of the second candidate route of the lightpath n2 is shown in table g252. In addition, the metric V cl,q is 5.537, and the metric V cl,q is 5.850. Therefore, the minimum metric is 5.537 for the first candidate route. The route to be selected is (L1, L4, L9) = (F2, F2, F3). Note that, as in table g251, when the variance values ​​are the same, the core selection unit 13 may select either core, and may select, for example, the one with the fewer number of core IDs (for example, F2 of F2 and F5).

[0110] As described above, in this embodiment, the number of wavelengths (number of optical paths) accommodated in each core is controlled by extracting and selecting optical path routes, cores to be used, and wavelengths using the variance value or standard deviation of the wavelength usage status on the candidate routes without any core continuity constraint. As a result, according to this embodiment, the number of wavelengths used in each core can be leveled, and the effect of reducing the power consumption of multi-core optical amplifiers can be obtained throughout the entire network.

[0111] In the above example, the core selection unit 13 may select all cores in steps S2C and S3C.

[0112] <Fifth embodiment> In this embodiment, an example will be described in which the average value of the number of wavelengths used per core in the link direction of the entire NW4 is used as the metric, and cores in the same core group are selected (conditions with core continuity constraints using the same core and wavelength continuity constraints). In this embodiment, the metric is calculated for the entire NW (network), the metric is calculated as an average value, and there is a core continuity constraint. In the following description, the multi-core fiber configuration shown in FIG. 2 and the network configuration shown in FIG. 3 will be used as examples.

[0113] FIG. 21 is a flowchart of an example of a processing procedure according to this embodiment. (Step S1D) The communication path allocation device 1 calculates an average value of wavelengths used in the link direction on each core after the optical path n0 is set. Fig. 22 is a diagram showing an example of an average value of wavelengths used in the link direction on each core after the optical path n0 is set according to this embodiment.

[0114] (Step S2D) The communication path allocation device 1 calculates a metric for setting the optical path n1. Note that the process performed in step S2D will be described later.

[0115] (Step S3D) The communication path allocation device 1 calculates a metric for setting the optical path n2. The process performed in step S3D will be described later.

[0116] Next, the process of step S2D for calculating an index (metric) for setting the optical path n1{(A,Z)=(0,8)} will be described.

[0117] (Step S21) The route candidate extraction unit 12 extracts candidate routes for the optical path n1 by, for example, calculating using the Dijkstra algorithm. In the following explanation, a case where link L1-link L2-link L5-link L10 is calculated as the candidate route for the optical path n1 as shown in Fig. 8 will be explained as an example. (Step S22) The core selection unit 13 sets the optical path n1 to be used for the second core group.

[0118] (Step S23D) The core selection unit 13 selects, as a used core for the optical path n1, a core route in which the average value of used wavelengths in the link direction on each core after the optical path n0 is set is the smallest.

[0119] (Step S26) The wavelength selection unit 14 selects a wavelength within the selected core by using, for example, the LF method or the FF method.

[0120] For example, in the example of FIG. 22, the core selection unit 13 selects the core F2, whose average value of utilized wavelengths is the minimum value 3.00, in step S23D.

[0121] Next, the process of step S3D for calculating an index (metric) for setting the optical path n2{(A,Z)=(0,7)} will be described. Fig. 23 is a diagram showing an example of the process of step S3D according to this embodiment.

[0122] (Step S31) The route candidate extraction unit 12 extracts candidate routes for the optical path n2 by calculating, for example, the Dijkstra algorithm. In the following example, a case will be described in which a first candidate route (link L1-link L4-link L9) and a second candidate route (link L3-link L8-link L11) are calculated as candidate routes for the optical path n2, as shown in Fig. 10. (Step S32) The core selection unit 13 sets the optical path n2 to be used in the second core group.

[0123] (Step S33D) The core selection unit 13 selects, as a used core for the optical path n2, a core route in which the average value of used wavelengths in the link direction on each core after the optical path n1 is set is the smallest.

[0124] (Step S34D) The core selection unit 13 selects, from among multiple candidate routes, a route with the largest minimum number of available wavelengths for each link on the candidate route. In the example of FIG. 22 etc., the maximum number of wavelengths for each link is set to 10. Here, the number of available wavelengths is (maximum number of wavelengths) - (number of wavelengths in use). In addition, when the minimum number of available wavelengths is the same, the core selection unit 13 selects the route with the largest total number of available wavelengths as the optical path route.

[0125] (Step S36) The wavelength selection unit 14 selects a wavelength within the selected core by using, for example, the LF method or the FF method.

[0126] Here, a method for selecting one route from a plurality of candidate routes will be described with reference to FIG. 23, table g301 is an example of a table showing the wavelength setting status after the optical path n1 is set. When table g301 is obtained, the core selection unit 13 first selects the core F2 with the smallest average value. Next, the core selection unit 13 obtains the number of available wavelengths in the core F2 and the minimum number of available wavelengths for the multiple candidate routes. The number of available wavelengths for the first candidate route (L1, L4, L9) is (8 (=10-2), 8 (=10-2), 2 (=10-8)), and the minimum number of available wavelengths is 2. The number of available wavelengths for the second candidate route (L3, L8, L11) is (4 (=10-6), 4 (=10-6), 9 (=10-1)), and the minimum number of available wavelengths is 4. Next, the core selection unit 13 selects, from the two candidate routes, a second candidate route having a larger minimum value of the number of available wavelengths in each link on the candidate route.

[0127] Here, the reason for selecting a route with a large minimum number of available wavelengths in this embodiment will be explained. The reason is to prevent a state (occurrence of wavelength blocking) in which there are no wavelengths and candidate routes that satisfy the wavelength continuity constraint as an optical path corresponding to a communication request when optical paths are set sequentially. The occurrence of wavelength blocking leads to an inability to set a communication path requested by a user, and is a situation that must be avoided by communication carriers that operate optical networks. If a route with few available wavelengths (a route with a small minimum number of available wavelengths) is selected, the number of wavelengths available on that route will be reduced, and the probability of wavelength blocking occurring on that route will increase. For this reason, in this embodiment, a route with as many available wavelengths as possible (a route with a large minimum number of available wavelengths) is selected.

[0128] As described above, in this embodiment, with the core continuity constraint, the number of wavelengths (number of optical paths) accommodated in each core is controlled by extracting and selecting the optical path route, the cores to be used, and the wavelengths using the average value in the link direction of the entire NW4. As a result, according to this embodiment, the number of wavelengths used in each core can be leveled, and the effect of reducing the power consumption of multi-core optical amplifiers can be obtained throughout the entire network.

[0129] In the above example, the core selection unit 13 may select all of the cores in steps S2D and S3D.

[0130] Sixth embodiment In this embodiment, an example is described in which the average value of the number of wavelengths used per core in the link direction on a candidate route is used as the metric, and cores in the same core group are selected (with core continuity constraint (use of the same core), with wavelength continuity constraint). In this embodiment, the metric is calculated for the candidate route, the metric is calculated as an average value, and there is a core continuity constraint. In the following explanation, the multi-core fiber configuration shown in FIG. 2 and the network configuration shown in FIG. 3 are used as examples.

[0131] FIG. 24 is a flowchart of an example of a processing procedure according to this embodiment. (Step S1D) The communication path allocation device 1 calculates an average wavelength usage average in the link direction on each core after the optical path n0 is set. Fig. 25 is a diagram showing an example of an average wavelength usage average in the link direction on each core after the optical path n0 is set according to this embodiment.

[0132] (Step S2E) The communication path allocation device 1 calculates a metric for setting the optical path n1. The process performed in step S2E will be described later.

[0133] (Step S3E) The communication path allocation device 1 calculates a metric for setting the optical path n2. The process performed in step S3E will be described later.

[0134] Next, the process of step S2E for calculating an index (metric) for setting the optical path n1{(A,Z)=(0,8)} will be described.

[0135] (Step S21) The route candidate extraction unit 12 extracts candidate routes for the optical path n1 by, for example, calculating using the Dijkstra algorithm. In the following explanation, a case where link L1-link L2-link L5-link L10 is calculated as the candidate route for the optical path n1 as shown in Fig. 8 will be explained as an example. (Step S22) The core selection unit 13 sets the optical path n1 to be used for the second core group.

[0136] (Step S23E) The core selection unit 13 selects, as a used core for the optical path n1, a core route for which the average value of the number of used wavelengths in the link direction on the candidate route after the optical path n0 is set is the smallest.

[0137] (Step S26) The wavelength selection unit 14 selects a wavelength within the selected core by using, for example, the LF method or the FF method.

[0138] For example, in the example of FIG. 25, the core selection unit 13 selects the core F2 in which the average value of the number of used wavelengths of link L1-link L2-link L5-link L10 on the candidate route is the minimum value 1.50 in step S23E.

[0139] Next, the process of step S3E for calculating an index (metric) for setting the optical path n2{(A,Z)=(0,7)} will be described. Fig. 26 is a diagram showing an example of the process of step S3E according to this embodiment.

[0140] (Step S31) The route candidate extraction unit 12 extracts candidate routes for the optical path n2 by calculating, for example, the Dijkstra algorithm. In the following explanation, a case will be explained in which a first candidate route (link L1-link L4-link L9) and a second candidate route (link L3-link L8-link L11) are calculated as candidate routes for the optical path n2, as shown in FIG. 10. (Step S32) The core selection unit 13 sets the optical path n2 to be used in the second core group.

[0141] (Step S33E) The core selection unit 13 selects, as a used core and candidate route for the optical path n2, a core route for which the average value of used wavelengths in the link direction of each core on each candidate route after the optical path n1 is set is the smallest.

[0142] (Step S36) The wavelength selection unit 14 selects a wavelength within the selected core by using, for example, the LF method or the FF method.

[0143] Here, a method for selecting one route from a plurality of candidate routes will be described with reference to FIG. 26, table g351 is an example of a table showing a wavelength setting status of the first candidate route after the optical path n1 is set, and table g352 is an example of a table showing a wavelength setting status of the second candidate route after the optical path n1 is set. Next, the core selection unit 13 selects the core F1, which has the smallest average value of the number of wavelengths used by each link on the candidate route, from among the two candidate routes, as the second candidate route. Note that, if the average values ​​are the same, the core selection unit 13 selects the route with the largest minimum value of the number of available wavelengths from each candidate route.

[0144] As described above, in this embodiment, with the core continuity constraint, the number of wavelengths (number of optical paths) accommodated in each core is controlled by extracting and selecting the optical path route, the cores to be used, and the wavelengths using the average value of the link directions on the candidate routes. As a result, according to this embodiment, the number of wavelengths used in each core can be leveled, and the effect of reducing the power consumption of multi-core optical amplifiers can be obtained throughout the entire network.

[0145] In the above example, the core selection unit 13 may select all of the cores in steps S2E and S3E.

[0146] Seventh embodiment In this embodiment, an example of randomly selecting cores in the same core group (with or without core continuity constraint, with wavelength continuity constraint) will be described. In this embodiment, the metric is calculated randomly, and there may or may not be a core continuity constraint. In the following description, the network configuration shown in FIG. 3 will be used as an example.

[0147] Fig. 27 is a diagram for explaining a processing method according to this embodiment. In the example shown in Fig. 27, the core of the first core group is core F4, and the cores of the second core group are F1, F2, F3, F5, F6, and F7. The number of wavelengths used is five for core F1, one for core F2, six for core F3, one for core F4, five for core F6, and four for core F7.

[0148] FIG. 28 is a flowchart of an example of a processing procedure according to this embodiment. (Step S71) The route candidate extraction unit 12 extracts candidate routes for the optical path n1 by, for example, calculating using the Dijkstra algorithm. In the following description, a case where link L1-link L2-link L5-link L10 is calculated as a candidate route for the optical path n1 as shown in FIG. 8 will be described as an example.

[0149] (Step S72) The core selection unit 13 sets the optical path n1 to be used for the second core group.

[0150] (Step S73) The core selection unit 13 randomly selects a core from the second core group.

[0151] (Step S74) The wavelength selection unit 14 selects a wavelength within the selected core using, for example, the LF method or the FF method.

[0152] Here, a processing example in the case where there is a core continuity constraint will be described. The communication path allocation device 1 stores information on a previously used combination of a route, link, and core (e.g., combination A) among combinations of routes, links, and cores that satisfy the wavelength continuity and core continuity constraints. Next, when setting a next optical path, the communication path allocation device 1 randomly selects a candidate from among combinations of routes, links, and cores other than combination A as candidates.

[0153] Here, a processing example in the case where there is no core continuity constraint will be described. The communication path allocation device 1 stores information on a previously used combination of a route, link, and core (for example, combination A) among combinations of a route, link, and core that satisfy wavelength continuity. Next, when setting a next optical path, the communication path allocation device 1 randomly selects a candidate from among combinations of a route, link, and core other than combination A as candidates.

[0154] As described above, in this embodiment, the number of wavelengths (number of optical paths) accommodated in each core is controlled by randomly selecting cores in the same core group. As a result, according to this embodiment, the number of wavelengths used in each core can be equalized, and the effect of reducing the power consumption of multi-core optical amplifiers can be obtained throughout the entire network.

[0155] Here, we will explain why the number of wavelengths used by each core can be equalized by randomly selecting cores in the same core group. There is always an upper limit to the number of wavelengths that can be set for each link core. Therefore, according to this embodiment, the wavelength setting is not biased toward a specific core by random selection, so that as the number of set wavelengths increases, the number of wavelengths used by each core will eventually spread out and be leveled out.

[0156] In the above example, the core selection unit 13 may select all the cores in step S72.

[0157] Eighth embodiment In this embodiment, an example will be described in which cores in the same core group are selected in a round robin manner (with or without core continuity constraints and with wavelength continuity constraints). In this embodiment, the metric is calculated in a round robin manner, and there may or may not be a core continuity constraint. In the following description, the network configuration shown in FIG. 3 will be used as an example.

[0158] Fig. 29 is a diagram for explaining a processing method according to this embodiment. As shown in Fig. 29, in this embodiment, a core in the same core group is selected in a round robin manner (the next core ID is selected) regardless of the number of wavelengths used for each core and each link.

[0159] FIG. 30 is a flowchart of an example of a processing procedure according to this embodiment. (Step S81) The route candidate extraction unit 12 extracts candidate routes for the optical path n1 by, for example, calculating using the Dijkstra algorithm. In the following description, a case where link L1-link L2-link L5-link L10 is calculated as a candidate route for the optical path n1 as shown in FIG. 8 will be described as an example.

[0160] (Step S82) The core selection unit 13 sets the optical path n1 to be used for the second core group.

[0161] (Step S83) The core selection unit 13 determines whether or not there are multiple candidate routes. If the core selection unit 13 determines that there are multiple candidate routes (step S83; YES), the process proceeds to step S84. If the core selection unit 13 determines that there are not multiple candidate routes (step S83; NO), the process proceeds to step S85.

[0162] (Step S84) The core selection unit 13 selects a route with the largest minimum number of available wavelengths for each link on the candidate route. If the smallest number of available wavelengths for each link on multiple candidate routes is the same, the core selection unit 13 selects, for example, a route with the largest total number of available wavelengths. After the process, the core selection unit 13 proceeds to the process of step S85.

[0163] (Step S85) The core selection unit 13 selects a core (within the same core group) having the next core ID of the core used in the optical path set in the previous candidate route (for example, link L1-link L2-link L5-link L10).

[0164] (Step S86) The wavelength selection unit 14 selects a wavelength within the selected core using, for example, the LF method or the FF method.

[0165] Here, a processing example in the case where there is a core continuity constraint will be described. The communication path allocation device 1 stores information on a previously used combination of a route, link, and core (for example, combination 1) among combinations of routes, links, and cores that satisfy the wavelength continuity and core continuity constraints, and information on the previous path number (pre-configured path number). Next, when setting the next optical path, if there are any combinations of routes, links, and cores other than combination 1 for which an optical path has not yet been set, the communication path allocation device 1 selects the combination with the smallest combination number among them (FIG. 31), and if there are no combinations for which an optical path has not been set, it selects the combination number next to the combination number with the largest pre-configured path number (FIG. 32).

[0166] 31 is a diagram for explaining a processing example of selecting the smallest combination number among combination numbers that do not have a set optical path among combination numbers that satisfy the wavelength continuity constraint and the core continuity constraint when there is a core continuity constraint. In the case of FIG. 31, the communication path allocation device 1 selects combination number 4, which is the smallest among combination numbers that do not have a set optical path.

[0167] 32 is a diagram for explaining a processing example of selecting the next combination number with the maximum already-set path number from among combination numbers that satisfy the wavelength continuity constraint and the core continuity constraint when there is a core continuity constraint. In the case of FIG. 32, the communication path allocation device 1 selects combination number 5 with the maximum already-set path number, and selects combination number 6 to be used when setting the next optical path. When there are multiple candidate routes, combinations of candidate routes, links, and cores are created in the same manner as above.

[0168] Next, a processing example in the case where there is no core continuity constraint will be described. The communication path allocation device 1 stores information on the previously used combination of route, link, and core (for example, combination 1) among combinations of route, link, and core that satisfy wavelength continuity, and information on the previous path number (pre-configured path number). Next, when setting the next optical path, if there is any combination of route, link, and core other than combination 1 for which an optical path has not yet been set, the communication path allocation device 1 selects the combination with the smallest combination number (FIG. 33), and if there is no combination for which an optical path has not been set, it selects the combination number next to the combination number with the largest pre-configured path number (FIG. 34).

[0169] 33 is a diagram for explaining a processing example of selecting the smallest combination number among combination numbers that do not have a set optical path among combination numbers that satisfy the wavelength continuity constraint and the core continuity constraint when there is a core continuity constraint. In the case of Fig. 33, the communication path allocation device 1 selects combination number 4, which is the smallest among combination numbers that do not have a set optical path.

[0170] 34 is a diagram for explaining a processing example of selecting the next combination number with the maximum already-set path number from among combination numbers that satisfy the wavelength continuity constraint and the core continuity constraint when there is a core continuity constraint. In the case of FIG. 34, the communication path allocation device 1 selects combination number 3 with the maximum already-set path number, and selects combination number 4 to be used when setting the next optical path.

[0171] In addition, when there is no core contiguity constraint, the processing is the same as when there is a core contiguity constraint, except that the combination number is increased. Also, when there are multiple candidate routes, combinations of candidate routes, links, and cores are created in the same manner as above.

[0172] As described above, in this embodiment, the number of wavelengths (number of optical paths) accommodated in each core is controlled by selecting cores in the same core group in a round robin manner. As a result, according to this embodiment, the number of wavelengths used by each core is eventually dispersed and equalized as the number of set wavelengths increases. As a result, according to this embodiment, the number of wavelengths used by each core can be equalized, and the effect of reducing power consumption of multi-core optical amplifiers can be obtained throughout the entire network.

[0173] In the above example, the core selection unit 13 may select all the cores in step S82.

[0174] In the communication path allocation device 1 configured in this way, the number of wavelengths allocated on the MC-EDFA is leveled by the optical path accommodation design, so the ratio of cladding pumping can be increased, and the power saving effect can be improved. Also, in the communication path allocation device 1, cladding pumping and core pumping and cladding pumping are used in combination, so power saving can be reduced compared to core pumping.

[0175] If the above-mentioned embodiments are applied to only core pumping to level out the number of wavelengths used in each core, for example, when 7 wavelengths are accommodated in a 7-core fiber, one wavelength is accommodated in each of cores 1 to 7. In this case, it is necessary to drive the core pumping lasers of all 7 cores, which increases power consumption. In contrast, in the method of each embodiment, if all seven wavelengths are accommodated in core 1, for example, only one core-pumped laser needs to be driven, and power consumption can be reduced compared to the case of core pumping.

[0176] (Modification) In each of the above-described embodiments, the wavelength selection unit 14 may use a method for wavelength selection other than the LF method and the FF method. In each of the above-described embodiments, the route candidate extraction unit 12 may use a method for route search other than the Dijkstra algorithm. In each of the above-described embodiments, the number of core groups is not limited to two, but may be three or more.

[0177] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and designs that do not deviate from the gist of the present invention are also included. [Industrial Applicability]

[0178] The present invention is applicable to an apparatus, method, and program for performing optical path accommodation design in a spatial division multiplexing optical network system (SDM-NW). [Explanation of symbols]

[0179] 100...SDM optical network, 1...communication path allocation device, 2...network operation device, 413, 413-1, 413-2, 423-3, 421...spatial multiplexing optical amplifier, 5, 5-1, 5-2, 5-3, 5-4, 5-5, 5-6, 5-7, 5-8...multicore fiber, 11...acquisition unit, 12...route candidate extraction unit, 13...core selection unit, 14...wavelength selection unit, 15...storage unit, 16...output unit, 21...wavelength utilization table creation unit, 411, 411-1, 411-2, 411-3...optical transceiver, 412, 412-1, 412-2, 412-3...OXC / OADM

Claims

1. a route candidate extraction unit that extracts connectable candidate routes from optical path routes connecting start points and end points of optical paths that accommodate communication demand in a network based on usage status information of the network; a core selection unit that selects a core, a link, and the optical path route that accommodates an optical path by leveling out a wavelength usage status, which is the number of wavelengths allocated to each core in an MC-EDFA (Multi-Core Erbium-Doped Fiber Amplifier) ​​of the entire network, based on usage status information of multi-core fibers of all links in the network or the candidate route; a wavelength selection unit that selects a wavelength to be used for the core, the link, and the optical path route selected by the route candidate extraction unit and the core selection unit; A communication path allocation device comprising:

2. The core selection unit selecting the core, the link, and the optical path route using a dispersion value or a standard deviation of a wavelength usage status, which is the number of wavelengths allocated to each core in the MC-EDFA of the entire network; The communication path allocation device according to claim 1.

3. The core selection unit selecting the core, the link, and the optical path route using a dispersion value or a standard deviation of wavelength usage of the candidate route; The communication path allocation device according to claim 1 .

4. The core selection unit selecting the core, the link, and the optical path route using an average value of wavelength usage in the link direction of the entire network; The communication path allocation device according to claim 1 .

5. The core selection unit selecting the core, the link, and the optical path route using an average value of the wavelength usage status in the link direction of the candidate route; The communication path allocation device according to claim 1 .

6. The core selection unit among the combinations of the optical path route, the link, and the core that satisfy the core continuity constraint and the wavelength continuity using the same core, information on the combination of the optical path route, the link, and the core that was used last time and information on the previously set path number are stored; At the time of the next path setting, if there is a combination in which the optical path is not set among the combinations of the optical path route, the link, and the core other than the combination, select the combination with the smallest combination number among the combinations in which the optical path is not set; If there is no combination in which the optical path is not set, select a combination number next to the combination number having the largest set path number. The communication path allocation device according to claim 1 .

7. extracting connectable candidate routes from optical path routes connecting start points and end points of optical paths that accommodate communication demand in the network based on usage status information of the network; Based on information on the usage status of multi-core fibers of all links in the network or the candidate route, select a core, a link, and an optical path route that accommodate the optical path by leveling out the wavelength usage status, which is the number of wavelengths allocated to each core in an MC-EDFA (Multi-Core Erbium-Doped Fiber Amplifier) ​​in the entire network; selecting wavelengths to use for the selected cores, links, and optical path routes; A communication path allocation method.

8. A program for causing a computer to function as the communication path allocation device according to any one of claims 1 to 6.

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