Route search device, route search method, and program

Abstract

This route search device comprises: a plurality of nodes; an area dividing unit that divides a communication network including edges connecting between the nodes into a plurality of areas on the basis of information on the nodes and that creates a first network graph representing the connection relationship between the areas; a first route search unit that uses the first network graph to search for one or more first routes from a start-point area including a start-point node to an end-point area including an end-point node; and a second route search unit that uses a second network graph representing the connection relationship between the nodes and the edges in the areas included in the first route to search for one or more second routes from the start-point node to the end-point node.

Description

[Technical field]

[0001] The present invention relates to a route search device, a route search method, and a program. [Background technology]

[0002] 2. Description of the Related Art In a communication network including a plurality of nodes and edges connecting the nodes, a technique for searching for an appropriate path between a start node and an end node is known.

[0003] Also, a route calculation device is known that divides a communication network into a plurality of meshes (rectangular regions), calculates partial routes, and calculates a route from a start node to an end node by joining the partial routes (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-137718 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional technology disclosed in Patent Document 1, the area is divided into a plurality of meshes based on geographical information such as a hazard map, map information, etc., and the division method is limited to rectangular regions. Therefore, when calculating a partial route with the conventional technology, the route that is actually desired to be created may not be found, and many similar routes are found, which results in a problem of requiring a long calculation time.

[0006] The embodiments of the present invention have been made in consideration of the above problems, and make it possible to efficiently search for an appropriate route in a communication network that includes a plurality of nodes and edges connecting the nodes. [Means for solving the problem]

[0007] In order to solve the above problem, a route search device according to an embodiment of the present invention provides a communication network including a plurality of nodes and edges connecting the nodes, the communication network including a plurality of nodes and edges connecting the nodes, the Shows communication demand an area division unit that divides an area into a plurality of areas based on information and creates a first network graph that represents the connection relationships of the areas; a first route search unit that uses the first network graph to search for one or more first routes from a start area including a start node to an end area including an end node; and a second route search unit that uses a second network graph that represents the connection relationships between the nodes and the edges in the areas included in the first routes to search for one or more second routes from the start node to the end node. The area division unit then classifies, among the nodes not belonging to the area, nodes within a predetermined range from the node with the greatest communication demand into one area. Effect of the Invention

[0008] According to an embodiment of the present invention, it becomes possible to efficiently search for an appropriate route in a communication network including a plurality of nodes and edges connecting the nodes. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an example of the configuration of a route search system according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram illustrating an example of the configuration of a route search device according to an embodiment of the present invention. [Diagram 3] 1 is a diagram illustrating an example of the configuration of an optical transmission network according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram showing an example of a network graph for macro search according to the present embodiment; [Figure 5A] FIG. 1 is a diagram showing an example of a topology information DB according to the present embodiment. [Figure 5B] FIG. 2 is a diagram showing an example of a topology information DB according to the embodiment. [Figure 6] FIG. 4 is a diagram illustrating an example of an area division information DB according to the embodiment. [Figure 7]4 is a flowchart showing an example of a route search process according to the first embodiment. [Figure 8] FIG. 4 is a diagram for explaining a macro search according to the first embodiment. [Figure 9] FIG. 11 is a diagram illustrating an example of a result of a macro search according to the first embodiment. [Figure 10A] FIG. 1 is a diagram (1) showing an example of a network graph for micro search according to the first embodiment. [Figure 10B] FIG. 2 is a diagram showing an example of a network graph for micro search according to the first embodiment. [Figure 11] FIG. 11 is a diagram showing an example of a result of a micro search according to the first embodiment. [Figure 12] 13 is a flowchart illustrating an example of a process for determining a divided area according to the second embodiment. [Figure 13] FIG. 2 illustrates an example of a hardware configuration of a computer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0011] <System configuration> 1 is a diagram showing an example of the configuration of a route search system according to the present embodiment. The route search system 1 includes a route search device 100, which is a computer that searches for an appropriate route from a start node to a finish node in an optical transmission network 10.

[0012] The optical transmission network (communication network) 10 is a backbone network such as an IP (Internet Protocol) communication network that realizes communication by optical signals. The optical transmission network 10 is an example of a communication network including a plurality of nodes and edges connecting the nodes. Here, the nodes include, for example, communication devices or communication buildings that configure the optical transmission network 10. The edges include transmission paths such as optical fibers. The edges may also be called links.

[0013] <Configuration of the route search device> 2 is a diagram showing an example of the configuration of a route search device according to this embodiment. The route search device 100 executes a predetermined program to realize, for example, an area division unit 201, a first route search unit 202, a second route search unit 203, a route determination unit 204, an interface unit 205, and a storage unit 206. Note that each of the above functional configurations may be distributed and arranged in a plurality of computers. Also, at least a part of each of the above functional configurations may be realized by hardware.

[0014] The area division unit 201 divides the optical transmission network 10, which includes a plurality of nodes and edges connecting the nodes, into a plurality of areas based on node information, and creates a network graph for macro search that shows the connection relationships of the divided areas.

[0015] Fig. 3 is a diagram showing a configuration example of an optical transmission network according to the present embodiment. In Fig. 3, an optical transmission network (communication network) 10 includes a plurality of nodes (N1 to N19) and edges connecting the nodes. The optical transmission network 10 is an example of a communication network.

[0016] 3, for example, into a plurality of areas (AN1 to AN7) indicated by dashed lines based on node information. Here, the node information may include various information such as coordinate information (location information) indicating the node's location, information indicating the node's communication demand, or distance from the node (for example, the distance that light can reach from the node without amplification). The area dividing unit 201 also creates a network graph for macro search indicating the connection relationships of the divided areas (AN1 to AN7).

[0017] 4 is a diagram showing an example of a network graph for macro search according to this embodiment. The network graph for macro search (first network graph) 400 is an undirected graph in which a plurality of divided areas (AN1 to AN7) are used as nodes and the areas are connected by edges. The network graph for macro search 400 is an example of the first network graph.

[0018] 2, the functional configuration of the route search device 100 will be further described. The first route search unit 202 uses the created network graph 400 for macro search to search for one or more routes (hereinafter referred to as macro search) from an area including a start node (hereinafter referred to as start area) to an area including an end node (hereinafter referred to as end area).

[0019] For example, the first route search unit 202 searches for one or more routes (hereinafter referred to as first routes) from a start area to an end area using a network graph 400 for macro search as shown in Fig. 4, using a known Dijkstra algorithm or the like. The Dijkstra algorithm is a method of determining a route with the smallest weight by setting weights indicating the cost (e.g., distance) of passing through the nodes and edges constituting a communication network. Note that the first route search unit 202 is not limited to using the Dijkstra algorithm, and may search for the first route using other methods.

[0020] The second route search unit 203 creates a network graph (second network graph) for micro search that indicates the connection relationships between nodes and edges in the area included in the first route searched by the first route search unit 202. In addition, the second route search unit 203 uses the created network graph for micro search to search for one or more routes from a start node to an end node (hereinafter referred to as micro search). Note that the network graph for micro search is an example of a second network graph.

[0021] For example, the second path search unit 203 uses a network graph for micro search to search for one or more paths from a start node to an end node (hereinafter, referred to as second paths) using a known Dijkstra algorithm, etc. Note that the second path search unit 203 is not limited to using the Dijkstra algorithm, and may search for the second path using other methods.

[0022] The route determination unit 204 determines, from the one or more second routes searched by the second route search unit 203, one or more second routes that satisfy the requirements.

[0023] The interface unit 205 is a user interface (UI) for a user to use a route search function provided by the route search device 100, or an application programming interface (API) for a user to use a route determination function provided by the route search device 100 from another device, etc. For example, a user (or another device, etc.) can use the interface unit 205 to set search conditions for a start node, an end node, etc. in the optical transmission network 10. In addition, a user (or another device, etc.) can use the interface unit 205 to obtain a result of a route determination process performed by the route search device 100, etc.

[0024] The storage unit 206 stores various information and data including a topology information DB (Database) 211, an area division information DB 212, and a route information DB 213, for example.

[0025] (Topology information DB) 5A and 5B are diagrams showing an example of a topology information DB according to this embodiment. The topology information DB 211 stores, for example, topology information 501 as shown in Fig. 5A and topology information 502 as shown in Fig. 5B.

[0026] Fig. 5A shows an example of topology information 501 indicating the connection relationship between nodes and edges included in the optical transmission network 10 as shown in Fig. 3. In the example of Fig. 5A, the topology information 501 includes information such as "node A", "node Z", "distance", and "edge number" as items.

[0027] "Node A" includes information on the "number" and "node type" of the node (node ​​A) connected to one side of the edge. "Number" is an identifier that identifies node A. "Node type" is attribute information of node A when there are multiple types of nodes. Here, it is assumed that there are three attributes of a node: OXC (Optical Cross Connect), REP (Repeater), and Thru (Through).

[0028] Here, OXC is an optical cross connect that switches wavelength-multiplexed signals on a wavelength-by-wavelength basis in the optical transmission network 10. REP is an optical repeater that relays optical signals. Thur is a connection point of optical fibers, for example, by fusion splicing or the like.

[0029] "Node Z" includes information on the "number" and "node type" of the node (node ​​Z) connected to the other side of the edge. "Number" is an identifier that identifies node Z. "Node type" is attribute information of node Z when there are multiple types of nodes. For example, Figure 5A shows that the edge with edge number "1001" is connected between a node with node number "N1" (node ​​N1) and a node with node number "N2" (node ​​N2).

[0030] The "distance" is information indicating the distance of the edge (the length of the transmission path between node A and node Z). The "edge number" is an identifier that identifies the edge.

[0031] Fig. 5B shows an example of topology information 502 indicating the connection relationships with nodes included in network graph 400 for macro search as shown in Fig. 4. In the example of Fig. 5B, topology information 502 includes information on "node A" and "node Z" as items, and indicates that "node A" and "node Z" are connected by an edge. For example, the example of Fig. 5B indicates that node "AN1" and node "AN2", node "AN2" and node "AN3", and node "AN6" and node "AN7" are each connected by an edge.

[0032] (Area division information DB) Fig. 6 is a diagram showing an example of an area division information DB according to the present embodiment. The area division information DB 212 stores in advance information used for dividing the optical transmission network 10 into a plurality of areas. In the example of Fig. 6, the area division information DB 212 stores coordinate information indicating the position of each node included in the optical transmission network 10. Note that, in the example of Fig. 6, the coordinate information is represented by x coordinates and y coordinates, but the coordinate information may be latitude, longitude, etc.

[0033] As an example, the area dividing unit 201 may divide the optical transmission network 10 into a plurality of areas based on the coordinate information of each node and geographical information such as prefectures. As another example, the area dividing unit 201 may use the interface unit 205 to display a plurality of nodes on a map based on the coordinate information of each node, and divide the optical transmission network 10 into a plurality of areas according to a setting operation by a user. In this case, the route searching device 100 may store the map information 214 in the storage unit 206, or may acquire the map information 214 from an external server or the like.

[0034] 6 is an example. For example, the area division information DB 212 may store information indicating the communication demand of the node in advance in addition to the coordinate information of the node. Here, the communication demand is, for example, information such as the communication bandwidth required for the node (the number of wavelength paths when the node is an OXC). In this case, the area division unit 201 may divide the optical transmission network 10 into a plurality of areas based on the communication demand of the node. Also, the route search device 100 may divide the optical transmission network 10 into a plurality of areas based on the distance r that light can reach from the node without amplification.

[0035] 2 is an example of a functional configuration of the route search device 100. For example, the first route search unit 202 and the second route search unit 203 included in the route search device 100 may be a single route search unit. Also, the storage unit 206 may be a storage device (e.g., a storage server, etc.) external to the route search device 100.

[0036] <Processing flow> Next, the process flow of the route search method according to this embodiment will be described.

[0037] [Example 1] Fig. 7 is a flowchart showing an example of a route search process according to the first embodiment. This process shows an example of a route search process in which the route search device 100 searches for a route from a start node to an end node in the optical transmission network 10 shown in Fig. 3, for example. In the actual path design of the optical transmission network 10, it is common to secure two or more routes for the purpose of improving reliability, etc., so here, an example of a process in which two routes that do not overlap with nodes and edges will be described.

[0038] In step S701, the area dividing unit 201 acquires topology information 501 of the optical transmission network 10, for example, as shown in Fig. 5A, from the topology information DB 211. This allows the area dividing unit 201 to grasp the configuration of the optical transmission network 10, for example, as shown in Fig. 3.

[0039] In step S702, the area dividing unit 201 determines divided areas for dividing the optical transmission network 10 into a plurality of areas. In the first embodiment, the area dividing unit 201 divides the optical transmission network 10 into a plurality of areas as shown by the dashed lines in FIG. 3 based on the coordinate information of the nodes stored in the area division information DB 212 and the area information such as prefectures included in the map information 214.

[0040] In step S703, the area dividing unit 201 creates a network graph (first network graph) 400 for macro search, for example as shown in FIG. 4, which represents the connection relationships among the divided areas (AN1 to AN7).

[0041] For example, the area division unit 201 defines each of the divided areas (AN1 to AN7) as a node. In the following description, the areas (AN1 to AN7) defined as nodes are called "area nodes" to distinguish them from the nodes (N1 to N19). Next, when a node included in one area node is connected to a node included in another area node, the area division unit 201 determines that the one area node and the other area node are in a connection relationship, and connects the one area node and the other area node with an edge. The area division unit 201 performs the same process for all area nodes, and creates a network graph 400 for macro search, for example, as shown in FIG. 4. The area division unit 201 connects edges so that multiple edges do not exist in the same section.

[0042] In step S704, the first route searching unit 202 determines route search conditions. For example, the first route searching unit 202 uses the interface unit 205 to set the start node and end node, etc., received from the user (or other device, etc.) as route search conditions. Here, as an example for explanation, the following explanation will be given assuming that the node "N2" is determined as the start node and the node "N8" is determined as the end node in the optical transmission network 10 as shown in FIG. 3.

[0043] In step S705, the first route search unit 202 uses the network graph 400 for macro search created by the area division unit 201 to search for one or more first routes from an area node including a start node (hereinafter referred to as a start area) to an area node including an end node (hereinafter referred to as an end area).

[0044] Fig. 8 is a diagram for explaining a macro search according to the first embodiment. In Fig. 8, an area node "AN1" is a start area 801 including a node "N2" that is a start node, and an area node "AN3" is an end area 802 including a node "N8" that is an end node.

[0045] First, the first route searching unit 202 performs an exhaustive search for a first first route (one first route) from the start area 801 to the end area 802. Next, the first route searching unit 202 searches for a second first route (another first route) for each of the exhaustively searched first first routes in turn. Note that in this embodiment, as an example, two first routes (a first first route and a second first route) are searched for, but this is not limiting, and the number of first routes searched by the first route searching unit 202 may be one or more other numbers.

[0046] Preferably, when searching for another first route, the first route searching unit 202 searches for a second first route by excluding nodes (area nodes) and edges (edges between area nodes) included in one first route from the macro search network graph 400. This allows a backup to be provided by another first route when, for example, a failure occurs in one first route.

[0047] When the first route searching unit 202 searches for the first route, the nodes (area nodes), edges, etc. of the network graph 400 for macro search may be weighted by, for example, distance, number of hops, etc. to search for the shortest route.

[0048] Fig. 9 is a diagram showing an example of a result of a macro search according to the first embodiment. In a result 900 of a macro search shown in Fig. 9, "area route information 1" corresponds to a first first route (one first route), and "area route information 2" corresponds to a second first route (another first route). In this way, by the macro search in step S705, a plurality of candidates for a combination of the first first route and the second first route can be obtained.

[0049] In step S706, the second route searching unit 203 creates a network graph (second network graph) for micro search indicating the connection relationships between the nodes and edges in the area included in the first route searched by the first route searching unit 202.

[0050] 10A and 10B are diagrams illustrating an example of a network graph for micro search according to the first embodiment. Fig. 10A illustrates an example of a network graph 1000a for micro search corresponding to area route information 1 "AN1-AN2-AN3" in the result 900 of the macro search illustrated in Fig. 9. In this case, the second route search unit 203 creates a network graph 1000a for micro search by excluding areas "AN4" to "AN7" other than areas "AN1", "AN2", and "AN3" included in the first route from the optical transmission network 10 illustrated in Fig. 3.

[0051] Fig. 10B shows an example of a network graph 1000b for micro search corresponding to area route information 2 "AN1-AN4-AN3" in the macro search result 900 shown in Fig. 9. In this case, the second route search unit 203 creates a network graph 1000a for micro search by excluding areas "AN2", "AN5" to "AN7" other than areas "AN1", "AN4", and "AN3" included in the second route from the optical transmission network 10 shown in Fig. 3. The second route search unit 203 creates the network graphs 1000a and 1000b for micro search for each candidate included in the macro search result 900 as shown in Fig. 9.

[0052] In step S707, the second path search unit 203 searches for one or more second paths from the start node to the end node using the created network graph for micro search. For example, the second path search unit 203 searches for a first second path (one second path) from the node "N2" which is the start node 1001 to the node "N8" which is the end node 1002 using a network graph 1000a for micro search as shown in Fig. 10A. In addition, the second path search unit 203 searches for a second second path (another second path) from the node "N2" which is the start node 1001 to the node "N8" which is the end node 1002 using a network graph 1000b for micro search as shown in Fig. 10B.

[0053] At this time, there is a possibility that edges or nodes may overlap between the two second routes in the area "AN1" which is the start point area and the area "AN3" which is the end point area. Therefore, after searching for the first second route, the second route search unit 203 searches for the second second route so that edges and nodes do not overlap with the first second route.

[0054] The second route search unit 203 performs a micro search on each candidate included in the macro search result 900 as shown in Fig. 9, and finds a first second route and a second second route. In addition, the second route search unit 203 stores the results of the micro search in a route information DB 213 as shown in Fig. 11, for example.

[0055] Fig. 11 is a diagram showing an example of a result of a micro search according to the first embodiment. This diagram shows an image of an example of a route information DB 213 that stores the result of a micro search by the second route search unit 203. In the example of Fig. 11, the route information DB 213 includes items such as "route 1", "route 2", "sum of distance", and "sum of number of OXCs". Furthermore, "route 1" and "route 2" each include items such as "route information", "total distance", and "number of OXCs".

[0056] The "route information" of "route 1" is information indicating the first second route searched by the second route searching unit 203. The "total distance" of "route 1" is the total distance of the first second route, and is calculated by the second route searching unit 203, etc., using, for example, the "distance" information in the topology information 501 of the optical transmission network 10 as shown in FIG. 5A. The "number of OXCs" of "route 1" is the number of OXCs through which the first second route passes, and is calculated by the second route searching unit 203, etc., based on, for example, the "node type" information in the topology information 501 of the optical transmission network 10.

[0057] The "route information" of "route 2" is information indicating the second second route searched by second route search unit 203. The "total distance" of "route 2" is the total distance of the second second route. The "number of OXCs" of "route 2" is the number of OXCs that the second second route passes through. The "sum of distances" is the sum of the "total distance" of "route 1" and the "total distance" of "route 2". The "sum of OXC numbers" is the sum of the "number of OXCs" of "route 1" and the "number of OXCs" of "route 2".

[0058] In step S708, the route determination unit 204 determines, as two routes, combinations of second routes that meet the requirements from among the combinations of second routes searched by the second route search unit 203. For example, when creating two second routes that have the smallest "sum of distances", the route determination unit 204 determines, from the route information DB 213 as shown in FIG. 11, the second routes "N2-N5-N7-N8" and "N2-N4-N9-N11-N10-N8" that have the smallest "sum of distances" as the two second routes.

[0059] Through the above processes, the route search device 100 becomes able to efficiently search for an appropriate route in an optical transmission network (communication network) 10 that includes a plurality of nodes and edges that connect the nodes.

[0060] [Example 2] 12 is a flowchart illustrating an example of a process of determining divided areas according to the embodiment 2. This process illustrates another example of the process of determining divided areas executed by the area dividing unit 201 in step S702 in FIG.

[0061] In step S1201, the area division unit 201 rearranges a plurality of nodes included in the optical transport network 10 in descending order of communication demand.

[0062] In the second embodiment, the route search device 100 stores information indicating the magnitude of communication demand of each node in addition to coordinate information in the area division information DB 212 as shown in Fig. 6. For example, the route search device 100 stores, in the area division information DB 212, the communication bandwidth required for each node as information indicating the magnitude of communication demand of each node, or, if the node is the number of OXCs, the number of wavelength paths, etc. as information indicating the magnitude of communication demand. This allows the area division unit 201 to refer to the area division information DB 212 and rearrange the multiple nodes included in the optical transmission network 10 in descending order of communication demand. The area division information DB 212 is an example of node information.

[0063] In step S1202, the area dividing section 201 sets the variable i to 1, and executes the processes of steps S1203 to S1206.

[0064] In step S1203, the area division unit 201 judges whether or not the i-th node already belongs to an area. If the i-th node does not belong to an area, the area division unit 201 shifts the process to step S1204. On the other hand, if the i-th node already belongs to any area, the area division unit 201 stops the process of step S1204 and shifts the process to step S1205.

[0065] When the process proceeds to step S1204, the area division unit 201 sets, for example, the nodes within a range of a radius r centered on the i-th node as one area. For example, the area division unit 201 sets the distance that light can reach without amplification as the radius r. However, the method of determining the radius r is not limited to this.

[0066] As another example, the area dividing unit 201 may set, as one area, nodes whose edge distance from the i-th node is within a predetermined range, instead of the radius r.

[0067] In step S1205, the area dividing unit 201 adds 1 to the variable i. Also, in step S1206, the area dividing unit 201 judges whether the value of the variable i is equal to or greater than the number N of nodes included in the optical transmission network 10. If the value of the variable i is equal to or greater than N, the area dividing unit 201 judges that the processing has been completed for all nodes included in the optical transmission network 10, and ends the processing of Fig. 12. On the other hand, if the value of the variable i is less than N, the area dividing unit 201 judges that the processing has not been completed for all nodes included in the optical transmission network 10, and returns the processing to step S1203.

[0068] Through the above processing, the area dividing unit 201 can divide the optical transmission network 10 into a plurality of areas based on the communication demand of each node included in the optical transmission network 10.

[0069] [Variations] 12, the area dividing unit 201 may rearrange the multiple nodes included in the optical transmission network 10 by a method other than communication demand. For example, the area dividing unit 201 may assign numbers to each node in order starting from an arbitrary node at the most terminal point. Thereby, for example, as shown in FIG. 3, numbers N1 to N19 can be set to each node included in the optical transmission network 10.

[0070] In this case, the area dividing unit 201 may execute the process of step S1203 in FIG. 12 for Ni (N1, N2, . . . N19).

[0071] <Hardware configuration example> The route search device 100 according to this embodiment can be realized, for example, by causing a computer to execute a program in which the processing contents described in this embodiment are written.

[0072] The above program can be recorded on a computer-readable recording medium (such as a portable memory) and can be stored or distributed. The above program can also be provided via a network such as the Internet or e-mail.

[0073] 13 is a diagram showing an example of the hardware configuration of a computer. In the example of FIG. 13, a computer 1300 includes a drive device 1301, an auxiliary storage device 1303, a memory device 1304, and a CPU (Central Processing Unit) 1305, all of which are connected to each other via a bus B. 05, an interface device 1306, a display device 1307, an input device 1308, and an output device 1309.

[0074] A program for implementing processing in computer 1300 is provided by a recording medium 1302 such as a CD-ROM or a memory card. When recording medium 1302 storing the program is set in drive device 1301, the program is installed from recording medium 1302 via drive device 1301 into auxiliary storage device 1303. However, the program does not necessarily have to be installed from recording medium 1302, and may be downloaded from another computer via a network. Auxiliary storage device 1303 stores the installed program as well as necessary files, data, and the like.

[0075] The memory device 1304 reads out and stores the program from the auxiliary storage device 1303 when an instruction to start the program is received. The CPU 1305 realizes the functions related to each unit described in this embodiment according to the program stored in the memory device 1304. The interface device 1306 is used as an interface for connecting to a network. The display device 1307 displays a GUI (Graphic User Interface) or the like according to a program. The input device 1308 includes a keyboard and mouse, buttons, a touch panel, or the like, and is used to input various operation instructions. The output device 1309 outputs the calculation results. Note that the route search device 100 may not include either or both of the display device 1307 and the input device 1308.

[0076] <Effects of the embodiment> In the route search system 1 of this embodiment, the optical transmission network 10 to be the subject of route search is divided into multiple areas based on node information, and a network graph 400 for macro search is created with each divided area as a node and the settings between the areas as edges.

[0077] In addition, the route search system 1 performs a macro search using the network graph 400 for macro search to identify the areas passed through on the way from the start node to the end node, and performs a micro search for a route from the start node to the end node within the range of that area.

[0078] As a result, the route search system 1 according to this embodiment can reduce the ratio of similar routes searched for and can search for a route that meets the requirements. Also, the route search system 1 can effectively search for route candidates that meet the route determination requirements by excluding unnecessary route candidates from a large number of existing route candidates, thereby reducing the calculation time for route search.

[0079] Furthermore, the route search process according to this embodiment makes it easy to efficiently determine redundant routes in order to improve reliability.

[0080] As described above, according to this embodiment, it becomes possible to efficiently search for an appropriate route in a communication network including a plurality of nodes and edges connecting the nodes.

[0081] <Summary of the embodiment> This specification discloses at least the following route search device, route determination method, and program. (Section 1) an area division unit that divides a communication network including a plurality of nodes and edges connecting the nodes into a plurality of areas based on information of the nodes, and creates a first network graph that represents the connection relationships of the areas; a first route search unit that searches for one or more first routes from a start area including a start node to an end area including an end node by using the first network graph; a second route search unit that searches for one or more second routes from the start node to the end node by using a second network graph that represents a connection relationship between the nodes and the edges in an area included in the first route; A route search device having the above configuration. (Section 2) 2. The route search device according to claim 1, wherein the area dividing unit divides the communication network into the plurality of areas based on coordinate information indicating positions of the nodes. (Section 3) the communication network is an optical transmission network; the area division unit divides the communication network into the plurality of areas based on a distance that light can travel from the node without amplification; 3. A route search device according to claim 1 or 2. (Section 4) 4. The route search device according to any one of claims 1 to 3, wherein the area division unit divides the communication network into the plurality of areas based on communication demands of the nodes. (Section 5) The first route search unit is Searching for a first route using the first network graph; excluding the node and the edge included in the one first route from the first network graph and searching for another first route; 5. A route search device according to any one of claims 1 to 4. (Section 6) The second route search unit, searching for a second route from the start node to the end node using a second network graph limited to the nodes and edges in an area included in the first route; searching for another second route from the start node to the end node by using another second network graph limited to the nodes and edges in an area included in the another first route; 6. A route search device according to claim 5. (Section 7) A process of dividing a communication network including a plurality of nodes and edges connecting the nodes into a plurality of areas based on information of the nodes, and creating a first network graph representing the connection relationships of the areas; A process of searching for one or more first routes from a start area including a start node to an end area including an end node using the first network graph; A process of searching for one or more second routes from the start node to the end node using a second network graph representing a connection relationship between the nodes and the edges in an area included in the first route; The route search method is executed by a computer. (Section 8) A process of dividing a communication network including a plurality of nodes and edges connecting the nodes into a plurality of areas based on information of the nodes, and creating a first network graph representing the connection relationships of the areas; A process of searching for one or more first routes from a start area including a start node to an end area including an end node using the first network graph; A process of searching for one or more second routes from the start node to the end node using a second network graph representing a connection relationship between the nodes and the edges in an area included in the first route; A program that causes a computer to execute the following.

[0082] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0083] 1. Route Search System 10 Optical transmission network (communication network) 201 Area division section 202 First Route Search Department 203 Second Route Search Unit 204 Route Determination Unit 212 Area division information DB (an example of node information) 400 Network graph for macro exploration (first network graph) 801 Starting Area 802 Destination Area 1000a, 1000b Network graph for micro search (second network graph)

Claims

1. an area division unit that divides a communication network including a plurality of nodes and edges connecting the nodes into a plurality of areas based on information indicating communication demands of the nodes, and creates a first network graph that represents connection relationships of the areas; a first route search unit that searches for one or more first routes from a start area including a start node to an end area including an end node by using the first network graph; a second route search unit that searches for one or more second routes from the start node to the end node by using a second network graph that represents a connection relationship between the nodes and the edges in an area included in the first route; having The area division unit is a route search device that divides the nodes that do not belong to the area into one area, starting from the node with the highest communication demand, and divides the nodes that are within a predetermined range from the node into one area.

2. The route search device according to claim 1 , wherein the area dividing unit divides the communication network into the plurality of areas based on coordinate information indicating positions of the nodes.

3. the communication network is an optical transmission network; the area division unit divides the communication network into the plurality of areas based on a distance that light can travel from the node without amplification; 3. A route search device according to claim 1 or 2.

4. The first route search unit, Searching for a first path using the first network graph; excluding the node and the edge included in the one first route from the first network graph to search for another first route; The route search device according to any one of claims 1 to 3.

5. The second route search unit, searching for a second route from the start node to the end node using a second network graph limited to the nodes and edges in an area included in the first route; searching for another second route from the start node to the end node by using another second network graph limited to the nodes and the edges in an area included in the another first route; The route search device according to claim 4.

6. an area division process for dividing a communication network including a plurality of nodes and edges connecting the nodes into a plurality of areas based on information indicating communication demands of the nodes, and creating a first network graph representing the connection relationships of the areas; A process of searching for one or more first routes from a start area including a start node to an end area including an end node using the first network graph; a process of searching for one or more second routes from the start node to the end node using a second network graph representing a connection relationship between the nodes and the edges in an area included in the first route; The computer executes The area division process is a route search method in which, among the nodes not belonging to the area, nodes within a predetermined range from the node with the highest communication demand are classified into one area.

7. an area division process for dividing a communication network including a plurality of nodes and edges connecting the nodes into a plurality of areas based on information indicating communication demands of the nodes, and creating a first network graph representing the connection relationships of the areas; A process of searching for one or more first routes from a start area including a start node to an end area including an end node using the first network graph; a process of searching for one or more second routes from the start node to the end node using a second network graph representing a connection relationship between the nodes and the edges in an area included in the first route; Run the following on your computer: The area division process is a program for dividing the nodes not belonging to the area into one area, in descending order of the node with the highest communication demand, and dividing the nodes within a predetermined range from the node into one area.

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