Plural paths finding method and network device adopting the method

[0001] [Technical field to which the invention belongs] The present invention relates to a route search method, particularly a method for increasing the probability of searching for a plurality of routes that do not pass through the same node, and a network device to which this method is applied. [0002] [Conventional technology] When data communication is performed in a network including a plurality of nodes, for example, in a broadcasting network for transmitting a video (and audio) signal, a plurality of broadcasting stations are connected to a transmission line as a node and via a plurality of nodes. The video signal is sent from one key station to another key station. [0003] Here, in order to improve the reliability of broadcasting, the same video signal is usually transmitted through a plurality of routes as a video signal transmission from a certain station to a receiving station. As a result, the receiving station receives the video signal without causing disturbance of the video by switching to the video signal transmitted through the other route and receiving the obstacle on the route transmitted through one route. Is possible. [0004] In order to secure such an aspect, it is necessary to set a plurality of routes on the network in advance before the start of the operation or after the start of the operation under predetermined conditions. For this purpose, a technique for searching a route to be set from a plurality of routes on the network is required. [0005] The Dijkstra method is known as a conventional technique for finding the shortest route among all the routes connecting a certain starting node to an ending node in a network. This method is, for example, an algorithm in which elements (distance, cost, etc.) are made into a matrix for all routes connecting nodes, and one most advantageous route for the elements is derived by matrix calculation. [0006] FIG. 1 is a diagram for explaining the concept of the Dijkstra method, in which the first shortest path is searched (first shortest path search a) as a procedure for searching a plurality of routes, and then the shortest path is searched. Search for the remaining n routes (nth route search b). [0007] That is, in the Dijkstra method, in FIG. 1, the section between two adjacent nodes is used as an element, and the distance is registered as an attribute for each section. Then, the distance of the section connecting all the adjacent nodes from a certain starting node is calculated, then the distance connecting all the adjacent nodes from each adjacent node is calculated, and by repeating these, to the ending node. It is an algorithm that determines the route with the shortest distance between the connected sections. [0008] When applying such an algorithm, it is possible to provide one shortest path. However, if multiple routes are required, nodes and sections may overlap. As shown in Fig. 2 as an example of a network, if a node or a part of a section is unavailable, multiple routes may be disabled. [0009] That is, in FIG. 2, it is assumed that the network is composed of node A to node I. If the starting node is designated as node A and the ending node is designated as node I and the first route searched by the Dijkstra method is A B E H I, the second route is always the first. It goes through the same node as one route. Therefore, if the common node becomes unusable, neither route becomes unusable. [0010] Also, if you try to find the second and subsequent routes by excluding the first route (do not pass through the same node or the same section), you must use a route other than the shortest route, so the second and subsequent routes There is a possibility that it cannot be used in a plurality of shortest paths because there is no detour route or route. In this way, in the case of the Dijkstra method, the difference in conditions between the first route and the second and subsequent routes becomes large. [0011] [Problems to be Solved by the Invention] Therefore, an object of the present invention is to provide a route search method for increasing the probability of searching for a plurality of optimal routes as much as possible without passing through the same node, and a network device to which the route search method is applied. [0012] Another object of the present invention is to provide a route search method for searching a plurality of highly reliable routes while avoiding the risk of network unavailability due to a failure of a node or a section. [0013] [Means for solving problems] The route search method according to the present invention that achieves the above-mentioned problems is a method of searching a plurality of routes connecting a starting node to an ending node in a network network connecting a plurality of nodes, and is connected to each of the plurality of nodes 2 One direction of the transmission line in the direction is defined as the X direction, the other direction is defined as the Y direction, the starting node and the ending node are specified, and the specified starting node and the ending node are respectively in the X direction. Search for the shortest route to connect with the node connected to the transmission line, and use this as the first route of the X group.<u style="single">Then, the X group</u>Excludes nodes on the first path<u style="single">, Said</u>X direction<u style="single">And Y direction</u>The shortest path is searched for the node connected to the transmission line in the above, and this is set as the second path of the X group, and the specified start node and the end node are connected to the transmission line in the Y direction, respectively. Search for the shortest route to connect with the node, and use this as the first route of the Y group.<u style="single">Then, the Y group</u>Excludes nodes on the first path<u style="single">, Said</u>X direction<u style="single">And Y direction</u>The shortest path is searched for the node connected to the transmission line in, and this is set as the second path of the Y group, and the first path and the second path of the X group are used.<u style="single">Of distance</u>The sum and the Y group 1st and 2nd paths<u style="single">Of distance</u>It is characterized in that the sum is compared and the group having a small sum is determined as the optimum route in the comparison. [0014] Further, a preferred aspect of the route search method according to the present invention that achieves the above-mentioned problems is that the search for each of the X group first route, the X group second route, the Y group first route, and the Y group second route is performed. What is done by Dijkstra's algorithm<u style="single">To</u>It is a feature. [0015] Further, in a preferable aspect of the route search method according to the present invention that achieves the above-mentioned problems, the search for the second route in the X group and the search for the second route in the Y group are each repeated by the Dijkstra method. It is characterized by. [0016] Furthermore, a preferred embodiment of the route search method according to the present invention that achieves the above-mentioned problems is characterized in that the shortest path having the shortest distance is searched by the Dijkstra method. [0017] Further, a preferred aspect of the route search method according to the present invention that achieves the above-mentioned problems is to further group all the sections connected to arbitrary nodes, excluding the sections included in the group, and again the X group. The feature is that each of the first route, the second route of the X group, the first route of the Y group, and the second route of the Y group is searched, and a detour route for the section included in the group is obtained. [0018] Furthermore, a preferred aspect of the route search method according to the present invention that achieves the above-mentioned problems is to attribute the number of times of use or the time of use with respect to the plurality of routes of the searched X group second route and Y group second route, respectively. It is characterized in that it is registered as, and it is determined whether or not the plurality of routes can be selected. The features of the present invention will be further clarified from the embodiments of the invention described below with reference to the drawings. [0019] BEST MODE FOR CARRYING OUT THE INVENTION FIG. 3 is a diagram illustrating a system configuration that realizes the route search method of the present invention. [0020] As a plurality of route search units, it has an X-direction route search module 1, a Y-direction route search module 2, and an optimum route search module 3. Each module can be realized by software processing. [0021] [0021] Now, with reference to a certain node, in the relationship with the node adjacent to it, the section connecting the adjacent node in the clockwise direction is defined as the X direction, and the line connecting in the opposite direction is defined as the Y direction. Then, the X-direction route search module 1 and the Y-direction route search module 2 search for the route separately for each of the X and Y directions. [0022] Further, each of the X-direction route search module 1 and the Y-direction route search module 2 performs the first shortest path search processes 10 and 20 according to the conventional Dijkstra method shown in FIG. 1, and then searches. The remaining n route search processes 11 and 21 other than the shortest route are performed. As a result, the probability that the optimum plurality of routes can be obtained can be increased. [0023] The optimum route module 3 compares the route information (distance, cost, etc.) as essential elements between the route searched by the X-direction route search module 1 and the route searched by the Y-direction route search module 2. It has a function 30 to perform. FIG. 4 is a diagram showing an embodiment when the method of the present invention is applied to a network operation system that controls and monitors a transmission line. [0024] In FIG. 4, a plurality of nodes A to I constituting the network are each connected to one or more transmission lines, and have a function of switching between those transmission lines. Each node A to I is connected to an operation system 40 that controls and monitors the entire network, and each node sets and switches a transmission line according to a command from the operation system 40. [0025] FIG. 5 is a system configuration diagram of the operation system 40 according to the present invention in FIG. [0026] The operation system 40 has a plurality of route search operation systems 400 as a main unit, a recording device 410 that stores various information tables shown in FIGS. 6 to 9, and an external device (GUI) having a GUI (Graphic User Interface) function. Send and receive data to and from 420. The multi-route search operation system 400 is further composed of the following functional processing units. Each functional part can be realized by software as explained in FIG. [0027] (1) O &amp; M control unit 401: Mainly, the part that controls the processing request / network status display by the external device (GUI) 420 receives commands from the system operator. [0028] (2) Route search processing unit 402: The route search processing request from the external device (GUI) 420 is received through the O &amp; M control unit 401, and the terminal data (node attribute data) and transmission path data stored in the storage device 410. It has a function to search for the optimum route based on the above. [0029] The route search processing unit 402 is configured to have the following submodules as shown in FIG. [0030] (a) X-direction route search module 1 (b) Y-direction route search module 2 (c) Optimal route selection module 3 (3) Transmission line setting request processing unit 403: For the route searched by the route search processing unit 402, a transmission line setting request for realizing the searched route is sent to each node constituting the route. Has a function. [0031] Next, the detailed operation of the operation system 400 provided with the present invention will be described below based on the route search processing flow shown in FIG. 10 by taking the network shown in FIG. 4 as an example. [0032] The system operator selects and inputs the start point node A and the end point node I by using the external device (GUI) 420 of the system (processing process P1). The O &amp; M processing unit 401 requests the route search processing unit 402 to perform processing in order to search for the optimum route of node A and node I selected by the system operator. [0033] Therefore, in the route search processing unit 402, the information table data [section information data (FIG. 6), node information data (FIG. 7), and connection group data (FIG. 8) stored in the storage devices 410 illustrated in FIGS. 6 to 9 ), Route information data (Fig. 9)] is acquired (processing step P2), and the search for the optimum route is started. First, the X-direction route search module 1 in the route search processing unit 402 performs the following processing. Here, for example, the following section information data is registered in advance in the section information table 411 shown in FIG. 6 as information for the section between the node AIs shown in FIG. -The direction connecting the two adjacent nodes in the clockwise direction is defined as the X direction (Fig. 11, indicated by the solid arrow), and the direction connecting in the opposite direction is defined as the Y direction (Fig. 11, indicated by the dotted arrow). Figure 6, item 4). -Register the distance (or the delay time corresponding to the distance, etc.) as an attribute in the section information data for each direction (Fig. 6, Item 3). First, the shortest path 1 from the starting node A to the ending node I is searched by the Dijkstra method or an algorithm similar to this, targeting only the elements and attributes in the X direction (processing step P3). This route is called the "X group first route" (see Fig. 12). In FIG. 12, when the first route is obtained only in the X direction (for example, A B), the first route is A B C E F I (indicated by a thick solid line). [0034] Next, the second search targets the elements and attributes in the X and Y directions, and further excludes the elements including the nodes that have passed through the "X group first path". The shortest path from the same starting node A to the same ending node I as the first search is searched by the Dijkstra method or an algorithm similar to this (processing step P4). This route is called the "X group second route" (see Fig. 13). [0035] The second route that does not go through the same node as the first route (shown by the solid line) in Fig. 12 is A D E H I (shown by the dotted line) or A D G H in Fig. 13. Either I (indicated by the alternate long and short dash line) is searched for as "X group second path". [0036] Next, the Y-direction route search module 2 in the route search processing unit 402 performs the following processing. [0037] The first time, only the elements and attributes in the Y direction are targeted, and the shortest path 3 from the same starting node A to the same ending node I is searched by the (Dijkstra) method or an algorithm similar to this (processing process). P5). [0038] This route is called the "Y group first route" (see Fig. 14). When the first route is obtained only in the Y direction (for example, B A), the first route is A D G H I (indicated by a thick solid line). The second time, the elements and attributes in the X and Y directions are targeted, and the elements including the nodes that have passed through the "Y group first route" are excluded. The shortest path from the same starting node A to the same ending node I is searched for by the Dijkstra method or an algorithm similar to this (processing step P6). This route is called the "Y group second route" (see Fig. 15). [0039] The second route that does not go through the same node as the first route (indicated by the thick solid line) in Fig. 14 is either A B E F I (indicated by the dotted line) or A B C F I (one point). Either of (indicated by the chain line) is searched as "Y group second route". [0040] Here, further, the X-direction route search module 1 or the Y-direction route search module 2 in the route search processing unit 402 excludes the elements including the nodes that have passed through the "first route" and the "second route" and processes them. If a different shortest path can be searched by the Dijkstra method or an algorithm similar to this in steps P4 and P6, these processes are repeated so that this path is called the "third path" and the shorter path is searched. It is possible (in FIGS. 13 and 15, two routes are shown as the searched routes after the "second route"). [0041] Then, the optimum route selection module 3 in the route search processing unit 402 performs the following processing. [0042] The total distance x of the "X group 1st route" (Fig. 12) and the "X group 2nd route" (Fig. 13), and the "Y group 1st route" (Fig. 14) and "Y group 2nd route" (Fig. 13). Compare the total y of the distances in Fig. 15) (processing step P7). Then, the group having the shorter total distance is selected and determined (processing step P8). [0043] Further, the system to which the route search method of the present invention is applied selects "X group" or "Y group", prioritizes a plurality of routes included in the group, and provides routes in the order of priority. For example, as shown in FIG. 16, the three clothing routes from node A to node B are prioritized from 1 to 3. [0044] Here, the priority can be specified for the above-mentioned attributes such as distance, number of uses, usage time, usage amount, user name, and usage group name, or an arbitrary priority can be specified for the route. It is possible. Then, a route list is created according to the priority for the optimum plurality of routes (processing step P9). [0045] Then, the optimum route searched by the route search processing unit 402 is registered as the confirmed information in the route information table 414 shown in FIG. Then, the transmission line setting request processing unit 403 transmits to each of the nodes A to I in the network shown in FIG. 4, and makes a corresponding route connection or a detour connection to set the transmission line (processing step P10). Here, the detour connection can be described with reference to FIG. In FIG. 17, when there is an intermediate route failure between node A and node B, another route is set between node a and node b. By the above processing step, it is possible to obtain a system for deploying a function of searching for a plurality of routes having a short distance as much as possible without going through the same node for each group. By such a method, it is possible to search and determine a plurality of routes having a short distance as much as possible without passing through the same node from a certain starting node to the ending node. [0046] For example, in FIG. 11, it is considered that the distances between the nodes have the following relationship. [0047] AB: 1 BC: 1 AD: 1.5 BD: 1.2 CF: 1.5 DE: 1.5 EF: 1.5 DG: 2.5 EH: 2 FI: 2.5 GH: 2 HI: 2 At this time, the distance of the "X group first path" (Fig. 12) is (1 + 1 + 1.5 + 2.5) = 6. Furthermore, the distance of the "X group second path" (Fig. 13) is the dotted line distance = (1.5 + 1.5 + 2 + 2 = 7, and the alternate long and short dash line distance = (1.5 + 2.5 + 2 + 2) = 8. , The sum of these distances x is x = (6 + 7 + 8) = 21. [0048] On the other hand, the distance of the "Y group first route" (Fig. 14) is (1.5 + 2.5 + 2 + 2) = 8. Furthermore, the distance of the "Y group second path" (Fig. 15) is dotted line distance = (1 + 1.2 + 1.5 + 2.5 = 6.2, alternate long and short dash line distance = (1 + 1 + 1.5 + 2.5) = 6. , The sum y of these distances is y = (8 + 6.2 + 6) = 20.2. [0049] As a result, the distance of the Y group becomes shorter. Therefore, in the above-exemplified distance, the necessary routes are selected in order of priority from the plurality of routes (3 routes in the example of FIG. 15) of the group shown in FIG. To. [0050] Here, as an extension of the present invention, various aspects described below can be provided. [0051] That is, in the processing step P10 in the operation flow of FIG. 10, it is possible to specify in advance how many types of routes are desired to be obtained from the external device (GUI) 420. It is preferable to provide a function from the external device (GUI) 420 that can select to search as many routes as possible in the processing steps P4 and P6 if not specified. [0052] If only one route can be searched, a function is provided in the processing process P8 to notify the external device (GUI) 420 or the storage device 410 of a warning, record the warning, and provide one route. If the route cannot be searched at all, a function is provided to notify the external device (GUI) 420 or the storage device 410 that the search is not possible and record it. [0053] In the comparison process in the process step P7, it is also possible to use another registered attribute instead of the above-mentioned distance for the element of the section for each direction. Static attributes other than distance include, for example, target / non-target identifier (Fig. 6, item 5), available time zone (Fig. 6, item 6), user name (Fig. 6, item 7), user group. There is a name (Fig. 6, item 8). These static attributes are generally subject to restrictions on use due to construction work, etc., and are displayed, changed, and recorded from the external device (GUI) 420. [0054] Dynamic attributes other than distance include frequency of use (Fig. 6, item 9), usage time (Fig. 6, item 10), usage (bandwidth) (Fig. 6, item 11), failure information (Fig. 6, item 11). There is item No. 12). [0055] Such dynamic attributes are subject to usage restrictions due to failures, etc., are automatically updated and recorded, and are displayed by the external device (GUI) 420. In addition, the O &amp; M control unit 401 is provided with a function for changing and recording the section information table 411 shown in FIG. [0056] For example, in the processing of the processing steps P3 to P6, a function that enables simultaneous registration of a plurality of types of attributes is provided for the element of the line for each direction in the X direction and the Y direction. As a result, in the processing steps P3 to P6, it is possible to search for a route by comparing with a plurality of types of attributes. [0057] Furthermore, the attribute is registered in the section information table 411 for the element called node (see Fig. 7). For example, the number of times of use is registered as an attribute for an element called a node (Fig. 6, Item 9), and the number of times of use is updated and recorded in the node included in the finally selected route. It is also possible to deploy a function to register a certain attribute instead of the number of times of use. [0058] [0058] Static attributes other than the number of uses include target / non-target identifiers (Fig. 7, item 4), available time zones (Fig. 7, item 5), user names (Fig. 7, item 6), and user groups. There is a name (Fig. 7, item 7). Static attributes are displayed, changed, and recorded and controlled by the external device (GUI) 420. [0059] Dynamic attributes other than the number of uses include usage time (Fig. 7, item 8), usage amount (Fig. 7, item 9), and failure information (Fig. 7, item 10). Dynamic attributes are automatically updated, recorded, and displayed, changed, and recorded by an external device (GUI) 420. [0060] Further, in the processing steps P3 to P6, it has a function of determining static attributes registered for elements such as intervals and nodes and excluding the elements from the target of route search. That is, if it cannot be used due to construction work, etc., it will not be subject to route search. [0061] Furthermore, a function to register warning values will be provided to dynamic attributes for failures registered for elements such as sections and nodes. When the warning value is exceeded, it has a function to warn and record that the warning value has been exceeded. [0062] Deploy a function to register regulation values (criteria that are excluded from route search) to dynamic attributes registered for elements such as sections and nodes (Fig. 6, Item 26). Then, in the processing steps P3 to P6, after the regulation value is exceeded, a function is provided to notify and record that the regulation value has been exceeded, and to exclude the element from the target of the route search. [0063] The detour connection process in the process step P10 is a function of automatically selecting whether to substitute the route when the route becomes unavailable. Alternatively, the route is bypassed when a node or section becomes unavailable after the route has already been provided. [0064] In this case, as an example, when searching for a detour for the node ab in the middle of the route between ABs as shown in FIG. 17, the detour is searched for as the starting node a and the ending node b according to the flow of FIG. 10 described above. Can be done. At this time, in the processing steps P3 to P6, the unusable node or section (dotted path section connecting the node ab in FIG. 17) is excluded from the search target. Then, it is realized by designating the start node a and the end node b of the disabled part in the route as the start node and the end node and searching for the detour route. [0065] At this time, if the detour route cannot be searched, the node before the disabled part (the node between node A and node a in FIG. 17) is set as the starting node, and the disabled part is used. The previous node (the node between node b and node B in FIG. 17) is set as the terminal node, and the detour route is searched again. As a search result, the detour route is displayed and recorded on the external device (GUI) 420. [0066] Further, in the processing step P10, it is possible to select whether or not to change the unusable part to the detour route. Alternatively, it is possible to select whether or not to return the detour route to the original route. [0067] Also, deploy a function to register a node and the line connecting the node as a "connection group" (see connection group table 413 shown in Fig. 8). For example, the connection group is a group in the Kanto area or the like. In this case, if it is desired to exclude the nodes in the connection group as elements, all the sections included in the "connection group" are excluded from the route search. Then, by designating the node from the external device (GUI) 420, it is possible to select whether or not the "connection group" is the target of the route search. Then, when the "connection group" is excluded, a detour for the "connection group" to be excluded can be searched. [0068] (Appendix 1) It is a method of searching for multiple routes connecting the starting node to the ending node in a network connecting multiple nodes. One direction of the two-way transmission line connected to each of the plurality of nodes is defined as the X direction, and the other direction is defined as the Y direction. Identify the starting node and the ending node, The shortest route connecting the specified start node and end node with the node connected to the transmission line in the X direction is searched for, and this is set as the first route of the X group. The shortest path is searched for the nodes connected to the other transmission lines in the X direction, excluding the node in the first path in the X direction, and this is set as the second path in the X group. The shortest route connecting the specified start node and end node with the node connected to the transmission line in the Y direction is searched for, and this is set as the first route of the Y group. The shortest path is searched for the nodes connected to the other transmission lines in the Y direction, excluding the node in the first path in the Y direction, and this is set as the second path in the Y group. Comparing the sum of the first and second paths of the X group with the sum of the first and second paths of the Y group, In the above comparison, the group with a small sum is determined as the optimum path. A multi-route search method characterized by this. [0069] (Appendix 2) In Appendix 1, The search for each of the X group first route, the X group second route, the Y group first route, and the Y group second route is characterized in that it is executed by the Dijkstra method. Multiple route search method. [0070] (Appendix 3) In Appendix 2, Further, a plurality of route search methods, characterized in that the search for the second route in the X group and the search for the second route in the Y group are repeatedly performed by the Dijkstra method, respectively. [0071] (Appendix 4) In Appendix 2, A plurality of route search method characterized in that the shortest route having the shortest distance is searched by the Dijkstra method. [0072] (Appendix 5) In Appendix 1, In addition, group all sections connected to any node and Excluding the section included in the group, the search for each of the X group 1st route, the X group 2nd route, the Y group 1st route, and the Y group 2nd route is performed again, and a detour for the section included in the group is performed. A multi-route search method characterized by finding a route. [0073] (Appendix 6) In Appendix 3, A multi-route search characterized in that the number of times of use or the usage time is registered as an attribute for each of the plurality of routes of the searched X group second route and the Y group second route, and whether or not the plurality of routes can be selected is determined. Method. [0074] (Appendix 7) A network search device that searches for multiple routes connecting the first node to the last node in a network that connects multiple nodes. One direction of the two-way transmission line connected to each of the plurality of nodes is defined as the X direction, the other direction is defined as the Y direction, and the information data of the plurality of nodes and the section connecting the nodes is defined. It has a database to store and a multiple route search operation system, and the multiple route search operation system has a route search processing function as a route search processing function. The starting node and the ending node are specified, the shortest route connecting the specified starting node and the ending node with the node connected to the transmission line in the X direction is searched for, and this is the X group first route. Then, the shortest route is searched for the nodes connected to the other transmission lines in the X direction, excluding the node in the first route in the X direction, and this is used as the second route in the X direction. Module and The shortest route connecting the specified start node and the end node by the node connected to the transmission line in the Y direction is searched for, and this is set as the first route in the Y group, and the first route in the Y direction is used. An X-direction route search module that searches for the shortest route for nodes connected to the other transmission lines in the Y direction, excluding a certain node, and uses this as the second route in the Y group. An optimum route selection module that compares the sum of the first and second paths of the X group with the sum of the first and second paths of the Y group, and determines the group with the smaller sum as the optimum route in the comparison. Have A network search device characterized by this. [0075] (Appendix 8) In Appendix 7, The search for each of the X group first route, the X group second route, the Y group first route, and the Y group second route is characterized in that it is executed by the Dijkstra method. Network search device. [0076] (Appendix 9) In Appendix 8, Further, a network search device characterized in that the search for the second route of the X group and the search for the second route of the Y group are repeatedly performed by the Dijkstra method, respectively. [0077] (Appendix 10) In Appendix 8, A network search device characterized in that the shortest path having the shortest distance is searched by the Dijkstra method. [0078] (Appendix 11) In Appendix 7, In addition, group all sections connected to any node and Excluding the section included in the group, the search for each of the X group 1st route, the X group 2nd route, the Y group 1st route, and the Y group 2nd route is performed again, and a detour for the section included in the group is performed. A network search device characterized by finding a route. [0079] (Appendix 12) In Appendix 9, A network search device characterized in that the number of times of use or the time of use is registered as an attribute for each of the plurality of routes of the searched X group second route and the Y group second route, and whether or not the plurality of routes can be selected is determined. .. [0080] [0080] [Effect of the invention] As described above, as described in the embodiments, the present invention can provide a route search method for increasing the probability of searching for a plurality of optimal routes as much as possible without going through the same node, and a network device to which the route is applied. Is. [Simple explanation of drawings] FIG. 1 is a diagram illustrating the concept of Dijkstra's algorithm. FIG. 2 is a diagram showing an example of a network. FIG. 3 is a diagram illustrating a program configuration that realizes the route search method of the present invention. FIG. 4 is a diagram showing an embodiment when the method of the present invention is applied to a network operation system that controls and monitors a transmission line. 5 is a configuration diagram of an operation system 40 according to the present invention in FIG. 4. FIG. FIG. 6 is a diagram showing a section information table. FIG. 7 is a diagram showing a node information table. FIG. 8 is a diagram showing a connection group table. FIG. 9 is a diagram showing a route information table after confirmation. FIG. 10 is a flow chart showing the operation of the route search unit. FIG. 11 is a diagram illustrating information for a section between node AIs. FIG. 12 is a diagram illustrating a first route of the X group. FIG. 13 is a diagram illustrating a second route of the X group. FIG. 14 is a diagram illustrating a first route of the Y group. FIG. 15 is a diagram illustrating a second route of the Y group. FIG. 16 is a diagram illustrating a wired order of routes. FIG. 17 is a diagram illustrating a detour connection of a route. [Explanation of symbols] 1 X-direction route search module 10 First shortest path search stroke in the X direction 11 Nth shortest path search stroke in the X direction 2 Y direction route search module 20 First shortest path search stroke in the Y direction 21 Nth shortest path search stroke in the Y direction 3 Optimal route search module 30 Route information comparison process 40 Network operating system