Communication management device, communication management method, and program

Abstract

To provide a communication management device which can suppress a communication amount when acquiring a connection state in a network.SOLUTION: A communication management device connected to a network 100 in which a plurality of nodes 2 are connected to each other, comprises: a storage unit 18 which holds a route table 5 formed on the basis of a communication hop number to each of a plurality of nodes 2 for a route 4 to each node 2 in the network 100; and a control unit 10 which refers to the route table 5 when an abnormality is detected in any node 2, and executes communication for acquiring the state for the node 2 that has notified of the occurrence of the abnormality in the route 4 to which the node 2 that has notified of the occurrence of the abnormality belongs and the node 2 located on the downstream side on the route 4 from the node 2.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Multi-hop networks have traditionally been used as communication systems. Multi-hop networks are configured, for example, by connecting multiple nodes in a mesh configuration. In multi-hop communication, a route with the minimum number of forwarding passes is selected as the communication path to each node, and a route with a large number of forwarding passes is not selected. When one of the nodes constituting a multi-hop network becomes unable to communicate, communication is maintained by autonomous route switching. When a node constituting a multi-hop network detects a change in its status, such as a link down or link up, it notifies a management server. For example, a link down state is detected when a port or connector inside the node cannot connect to another node and communication is disabled. For example, a link up state is detected when a new node is added to the network. The management server monitors the multi-hop network, identifies the location of the failure, and is used for repair and maintenance. For example, Patent Document 1 describes a technology related to changing monitoring path settings when a node that cannot communicate is detected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4447429 Summary of the Invention [Problem to be solved by the invention]

[0004] In order for the management server that manages the network to detect node or link failures in a mesh network, it needs to obtain the connection status of each node. However, if the management server were to obtain information from all nodes configured in a mesh connection, the acquisition time and communication volume would increase linearly as the number of nodes in the network increases. In other words, since the acquisition time and communication volume increase linearly with the number of nodes, there was a problem of straining communication within the network.

[0005] An object of the present invention is to provide a communication management device, a communication management method, and a program that make it possible to reduce the amount of communication when acquiring the connection status in a multi-hop network. [Means for solving the problem]

[0006] (1) The communication management device is a communication management device connected to a network in which multiple nodes are interconnected, and is equipped with a memory unit that holds a route table formed based on the number of communication hops to each of the multiple nodes for the route to each node in the network, and a control unit that, when an abnormality is detected at any node, refers to the route table and, on the route to which the node that notified the occurrence of the abnormality belongs, performs communication to obtain status with the node that notified the occurrence of the abnormality and with nodes located downstream on the route from the node that notified the occurrence of the abnormality.

[0007] (2) In the communication management device of (1), the control unit identifies the location of the abnormality in the network based on which node has notified the occurrence of the abnormality.

[0008] (3) In the communication management device of (2), the control unit acquires the route created after the occurrence of the abnormality based on the acquired location of the abnormality.

[0009] (4) In the communication management device of (1) to (3), the control unit acquires the routing table of the node that notified the occurrence of the abnormality and the node connected downstream of the node.

[0010] (5) A communication management method is a communication management method in a network in which multiple nodes are interconnected, in which a communication management device connected to the network holds a route to each node in the network as a route table formed based on the number of communication hops to each of the multiple nodes, and when an abnormality is detected at any node, the communication management device performs communication to obtain status with the node that notified the occurrence of the abnormality and with nodes connected downstream from the node on the route to which the node that notified the occurrence of the abnormality belongs.

[0011] (6) The program causes a communication management device connected to a network in which multiple nodes are interconnected to retain routes to each node in the network as a route table formed based on the number of communication hops to each of the multiple nodes, and when an abnormality is detected at any node, causes the program to execute communication to obtain status on the route to which the node that notified the occurrence of the abnormality belongs, to communicate with the node that notified the occurrence of the abnormality and with nodes connected downstream from that node. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a communication management device, a communication management method, and a program that enable the amount of communication traffic to be reduced when the management server acquires the connection status within a network. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram illustrating a multi-hop network according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram illustrating a hardware configuration of a management server according to an embodiment of the present invention. [Figure 3] FIG. 2 is a block diagram illustrating a functional configuration of a management server according to an embodiment of the present invention. [Figure 4] FIG. 1 is a schematic diagram illustrating a normal initial state of a multi-hop network according to an embodiment of the present invention. [Figure 5] 1 is a schematic diagram illustrating a case where an abnormality occurs in a multi-hop network according to an embodiment of the present invention. [Figure 6] 1 is a schematic diagram showing a case where an abnormality occurs in a link in a multi-hop network according to an embodiment of the present invention and a route is changed. [Figure 7] 1 is a schematic diagram showing a routing table and routes in a normal initial state of a multi-hop network according to an embodiment of the present invention; [Figure 8] 1 is a schematic diagram showing a routing table and a route when an abnormality occurs in a link in a multi-hop network according to an embodiment of the present invention and the route is changed; DETAILED DESCRIPTION OF THE INVENTION

[0014] A multi-hop network communication management method according to an embodiment of the present invention will be described below with reference to the drawings. In each drawing, identical components are assigned the same reference numerals. Furthermore, if components have similar functions and no particular distinction is required, they are not distinguished by reference numerals. If components have similar functions but require special distinction, the components are distinguished from one another by adding an additional lowercase alphabet to the reference numeral.

[0015] (First embodiment) FIG. 1 illustrates a multi-hop network 100 according to a first embodiment of the present invention. A management server 1, which serves as a communication management device, is connected to the multi-hop network 100 via a higher-level node and manages communications within the network. The multi-hop network 100 is a mesh network including nodes 2, which are relay devices with relay capabilities, and links 3 connecting the nodes 2. In FIG. 1, the nodes 2 are represented by circles, and the links 3 connecting the nodes 2 are represented by lines connecting the nodes 2. A mesh network is a type of communication network configuration in which multiple nodes 2 form a mesh-like transmission path on an equal footing to transfer data. A mesh network forms a network of any shape by connecting adjacent nodes 2. In this embodiment, the nodes 2 are communication units, such as optical communication units or wireless communication units, and communication between the nodes 2 is performed using optical signals or wireless radio signals. In FIG. 1, nodes 2c and 2d communicate, for example, using optical signals or wireless radio signals. In FIG. 1, the link 3 through which this signal communication is possible is indicated by "3c." Also, in Fig. 1, nodes 2g and 2l communicate with node 2h, for example, using optical signals or radio wave signals. In Fig. 1, links 3 capable of communicating, for example, optical signals or radio wave signals are indicated by "3j" and "3n." Also, in Fig. 1, nodes 2d and 2h communicate with, for example, optical signals or radio wave signals. In Fig. 1, link 3 capable of communicating, for example, optical signals or radio wave signals is indicated by "3g."

[0016] In the example shown in FIG. 1 , data output from the management server 1 to node 2p or data input from node 2p to the management server 1 is transferred via path 4 (nodes 2a, 2e, 2i, 2m, 2n, 2o, and 2p) indicated by a thick line. This path 4 is autonomously configured by each node 2 in the multi-hop network 100 based on the communication status with other nodes 2, etc. The management server 1 acquires and manages the data transfer path within the multi-hop network 100 based on information received from each node 2. This allows the management server 1 according to this embodiment to efficiently grasp the status of the multi-hop network 100 when a malfunction or abnormality occurs in node 2 or link 3. A communication management method executed by the management server 1 will be described below with reference to FIGS. 2 to 7.

[0017] Fig. 2 is a block diagram showing the hardware configuration of the management server 1. As shown in Fig. 2, the management server 1 includes a control unit 10, an input / output unit 16, a communication unit 17, and a storage unit 18. The control unit 10 includes a processor 11, a read-only memory (ROM) 12, a random access memory (RAM) 13, a bus 14, and an input / output interface 15. The management server 1 may be a general-purpose personal computer capable of executing various functions by installing various programs thereon, or may be a computer incorporated into dedicated hardware.

[0018] The processor 11 performs various calculations and processes. The processor 11 is, for example, a central processing unit (CPU), a micro processing unit (MPU), a system on a chip (SoC), a digital signal processor (DSP), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field-programmable gate array (FPGA). Alternatively, the processor 11 is a combination of two or more of these. The processor 11 may also be a combination of these with a hardware accelerator or the like.

[0019] The processor 11, ROM 12, and RAM 13 are connected to one another via a bus 14. The processor 11 executes various processes in accordance with a program recorded in the ROM 12 or a program loaded into the RAM 13. A part or all of the program may be incorporated into the circuitry of the processor 11.

[0020] The bus 14 is also connected to an input / output interface 15. To the input / output interface 15, an input / output unit 16, a communication means 17, and a storage unit 18 are connected.

[0021] The input / output unit 16 is electrically connected to the input / output interface 15 via a wired or wireless connection. The input / output unit 16 is composed of an input unit such as a keyboard and a mouse, and an output unit such as a display for displaying captured images and a speaker for amplifying audio. The input / output unit 16 may be configured such that the display function and the input function are integrated, such as a touch panel.

[0022] The communication means 17 is a device that allows the processor 11 to communicate with other devices, particularly with each node 2, via the multi-hop network 100. The storage unit 18 is a storage device such as a hard disk drive (HDD) or a solid state drive (SSD) that stores node information and link information, etc., which will be described later.

[0023] The hardware configuration shown in Fig. 2 is merely an example and is not limited to this configuration. In addition to configurations consisting of various processing units such as single processors, multiprocessors, and multicore processors, combinations of these processing units with processing circuits such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field-Programmable Gate Arrays) may also be used to realize the functional configuration of a processor. Instead of the management server 1 having the memory unit 18, a configuration in which the memory unit 18 is provided separately may also be used.

[0024] Also, for example, the management server 1 may be remotely controlled by a device not shown in FIG. 1 through the multi-hop network 100 based on the communication means 17 .

[0025] FIG. 3 is a block diagram showing the functional configuration of the management server 1 according to this embodiment. As shown in FIG. 3, the management server 1 has, as its functional configuration, a node status acquisition means 101, a path acquisition means 102, and a state change acquisition means 103, which are realized by the processor 11 shown in FIG. 2 and the like. The node status acquisition means 101 acquires the state of each node 2. Specifically, the node status acquisition means 101 receives, from each node 2, a path table 5 and the like, which is information indicating the connection relationship with other nodes 2 regarding data transfer, via the communication means 17. An example of the structure of the path table 5 created in each node 2 will be described later. The path acquisition means 102 acquires, from the path table 5 received by the node status acquisition means 101, a tree-shaped path indicating the communication path between the management server 1 and each node 2. The state change acquisition means 103 acquires changes in the communication state of the node 2 based on information received from each node 2. As will be described in detail later, the state change acquisition means 103 has a function of identifying the location of the abnormality when it is determined that an abnormality has occurred on the network 100. In the management server 1, based on the state change related to the node 2 obtained by the state change obtaining means 103, the node state obtaining means 101 obtains the state of the node 2 (for example, node 2m in the example shown in FIG. 1) located downstream on the path 4 including the node 2 whose state has changed as seen from the management server 1 (for example, in the example shown in FIG. 1, an abnormality is detected in node 2i). When an abnormality is detected in any node 2, the management server 1 executes communication for obtaining the state of the node 2 (for example, node 2i in the example shown in FIG. 1) that notified the occurrence of the abnormality and all nodes 2 located downstream of the node 2 (for example, nodes 2m, 2n, 2o, and 2p in the example shown in FIG. 1) that notified the occurrence of the abnormality on the path 4 to which the node 2 that notified the occurrence of the abnormality belongs.

[0026] Hereinafter, details will be described based on an example of a multi-hop network 100 shown in FIGS.

[0027] Fig. 4 is a diagram more schematically illustrating the multi-hop network 100 shown in Fig. 1. The nodes 2 include nodes 2a to 2p, which are connected by a link 3. Fig. 4 shows a normal state.

[0028] A management server 1 connected to a multi-hop network 100 maintains a route 4 to each node 2 in the multi-hop network 100 as a tree-structured route 4 having multiple branches formed based on the number of communication hops to each of the plurality of nodes 2. The route 4 in the multi-hop network 100 is determined by the minimum number of hops, and is therefore the shortest route 4. The route 4 from the root node 2 to each node 2 forms a tree structure. In the example of FIG. 4 , the route 4 is represented by a thick line, and with node 2a as the root node, route 4a connecting nodes 2a, 2e, 2i, 2m, 2n, 2o, and 2p; route 4b connecting nodes 2a, 2b, 2f, and 2j; route 4c connecting nodes 2a, 2b, 2c, 2g, and 2k; and route 4d connecting nodes 2a, 2b, 2c, 2d, 2h, and 2l are formed. These routes 4a to 4d form multiple branches, forming a tree structure. These routes 4 are connected to the management server 1. This means that any change that occurs in any link on the tree or in node 2 affects the state of node 2 and route 4 connected to the end of that branch.

[0029] Although the multi-hop network 100 has a mesh structure, the communication connections between the nodes take the form of a tree structure as described above. In the example of Figure 4, a mesh is configured, but links 3 that are not incorporated into route 4 include, for example, links 3h, 3i, 3j, 3o, 3p, 3q, 3s, 3t, and 3u. Although these links 3 are physically connected, they are not selected as route 4 and are not used for communication. The mesh structure provides redundancy to route 4.

[0030] The lines that make up link 3 are always connected in a state where communication is possible while the multi-hop network 100 is in operation. The lines between nodes 2 are mesh-like and complex, but when a route 4 is determined, only one route 4 is determined from each node 2 to the management server 1. The route 4 is determined based on the shortest number of hops from the node 2 to the management server 1. If there are multiple routes 4 with the same number of hops, the route 4 that was established first is adopted, and multiple routes 4 are not adopted for one node 2. The route table 5 held by each node 2 is set so that routes 4 from the management server 1 are formed as a specific single route without crossing each other. The route 4 is tree-shaped.

[0031] FIG. 5 shows an example of a failure occurring in the multi-hop network 100. In the multi-hop network 100, connections can be interrupted. This can be caused, for example, by an optical line break, an optical port failure, or deterioration of radio wave conditions due to weather or the presence of an obstacle. In the example shown in FIG. 5, a failure occurs in link 3k connecting node 2e and node 2i. At this time, nodes 2 (e.g., nodes 2i, 2m, 2n, 2o, and 2p in the example shown in FIG. 5) that have the failed link 3k on their route 4a lose their route 4 to the management server 1. Here, in FIG. 5, node 2e loses signals from node 2i listed in the route table 5, and is in an abnormal state. Then, due to the abnormal link 3, in path 4 (for example, in the example shown in FIG. 5, path 4a shown in FIG. 4), which is a branch of the tree structure to which node 2 in which the abnormality occurred (for example, nodes 2i, 2m, 2n, 2o, and 2p in the example shown in FIG. 5) belongs, node 2 that is farther away from management server 1 than link 3k in which the abnormality occurred, in other words, node 2 connected downstream in path 4a, becomes unable to communicate with management server 1 via path 4. That is, in the example shown in FIG. 5, nodes 2i, 2m, 2n, 2o, and 2p cannot communicate with management server 1 via path 4.

[0032] FIG. 6 shows the state after node 2 constructs new route 4 after an abnormality occurs in link 3k. The new route 4 is not established by the management server 1; the management server 1 simply monitors the status of the multi-hop network 100. Route 4 to the management server 1 is determined by node 2. As described with reference to FIG. 4, node 2 finds route 4 by itself based on the minimum number of hops. In the example of FIG. 6, for nodes 2i, 2m, 2n, 2o, and 2p that can no longer communicate with the management server 1 via route 4a, new route 4 is constructed for node 2i via links 3a, 3e, 3l, and 3o; for node 2m via links 3a, 3e, 3l, 3s, and 3v; for node 2n via links 3a, 3e, 3l, and 3s; for node 2o via links 3a, 3e, 3l, and 3s; and for node 2p via links 3a, 3e, 3l, 3s, and 3w. For nodes 2b, 2c, 2f, 2g, 2j, 2k, 2d, 2h, and 2l, there is no change to route 4.

[0033] 6, in a situation where link 3k goes down, node 2 whose connection status has changed transmits a link down signal indicating link down detection to management server 1. The link down signal is transmitted by node 2 (for example, nodes 2e and 2i in the example shown in FIG. 5) that detects that the connection of link 3 has been cut off.

[0034] The operation of node 2e will be described in detail. Node 2e detects that link 3k has gone down. Because link 3 to the downstream side of route 4a has become invalid, node 2e sends a notification of a route abnormality on the downstream side (2i, 2m, 2n, 2o, 2p) to the adjacent nodes 2 (2a, 2f) that are valid. Because the selected route to management server 1 is valid in node 2e, a link down signal is sent to management server 1 via node 2a.

[0035] Next, the operation of node 2i will be described in detail. Node 2i detects that link 3k has gone down. Because route 4 to the upstream side of route 4a has become invalid, node 2i sends a route abnormality on the upstream side (2a, 2e) to the valid adjacent nodes 2 (2m, 2j). Node 2i then sends a route request to management server 1 to the valid adjacent nodes 2 (2m, 2j). In this case, for example, a link down signal is sent to management server 1 via node 2j.

[0036] The management server 1 receives a link down signal from the node 2e and the node 2i, which is a notification that a link down has occurred on the link 3k.

[0037] 7 and 8, a description will be given of changes in the routing table 5 in the multi-hop network 100 before an abnormality occurs (see FIG. 7) and after an abnormality occurs (see FIG. 8). FIGS. 7 and 8 show the network portion enclosed by the dashed line in the upper left of FIG. 4, rotated 90 degrees to the left. The management server 1 stores the routing table 5 of each node 2 shown in FIG. 7 in the storage unit 18. The route acquisition means 102 derives and acquires the route 4 based on the routing table 5. In the example shown in FIG. 7, routes 4a and 4b, which are also shown in FIG. 4, are listed.

[0038] As shown in FIG. 7, each node 2 has a routing table 5. The routing table 5 of node 2a is assigned a symbol such as 5a, and the routing table 5 of node 2b is assigned a symbol such as 5b. The routing table 5 of each node 2 is identified by the address assigned to the node 2 having the routing table 5. For example, according to the routing table 5e corresponding to node 2e, the address of node 2e is 192.168.0.2. However, the addresses shown in FIGS. 7 and 8 are merely examples for the purpose of explaining this embodiment and are not intended to limit the present invention or this embodiment. The routing table 5 specifies the final destination and the next forwarding node 2. Referring to the routing table 5i of node 2i, the address 10.0.0.5 of the management server 1, which is the final destination, is registered, and the forwarding destination to reach the management server 1 is 192.168.0.1, the address of the root node 2a. This address 192.168.0.1 does not exist among the nodes 2 to which node 2i can directly forward. For this reason, in the routing table 5i, the address 192.168.0.1 is further registered as the destination, and the address 192.168.0.2 of the node 2e, which is a destination that can be directly forwarded from the node 2i, is recorded as the forwarding destination to reach the root node 2a.

[0039] 8 illustrates a state in which, as in FIG. 5, an abnormality has occurred in which link 3k connecting node 2e and node 2i is disconnected. At this time, in multi-hop network 100, node 2 autonomously constructs a route to management server 1. As shown in FIG. 8, for example, route 4 is changed so that node 2i is connected to management server 1 via node 2j. Node 2i's routing table 5i is rewritten to reflect this change. The rewritten portion in the figure is indicated by a dashed line. The forwarding destination corresponding to destination 10.0.0.5 of management server 1 remains unchanged at 192.168.0.1, the address of root node 2a. However, the forwarding destination corresponding to destination address 192.168.0.1 of root node 2a has been updated to 192.168.0.4, the address of node 2j. As a result, information from node 2i is now sent to management server 1 via node 2j.

[0040] The operation of constructing a route within the multi-hop network 100 described above is executed autonomously by the node 2. The operation of the management server 1 that grasps this situation will now be described. The node status acquisition means 101 of the management server 1 acquires the route table 5 from the node 2 as appropriate and stores it in the storage unit 18. The route acquisition means 102 derives and acquires the tree-structured route 4 based on the list of the route table 5. When the status change acquisition means 103 acquires a notification of a change in the node 2 or the link 3 (for example, a notification due to a link up / link down / bypass occurrence and resolution), the node status acquisition means 101 executes re-acquisition of the route table. In other words, the notification of a change in the node 2 or the link 3 triggers re-acquisition of the route table.

[0041] The status change acquisition means 103 receives notification of a unique address from a node 2 that has detected an abnormality and identifies the location on the multi-hop network 100 based on this unique address. More specifically, the process is as follows: The management server 1 stores the routing table 5 of each node 2 in the storage unit 18. When each node 2 notifies the management server 1 of information, it also notifies its own address at the same time. The status change acquisition means 103 of the management server 1 uses this unique address to identify the location on the multi-hop network 100 of the node 2 that notified the information. When the status change acquisition means 103 detects that two adjacent nodes 2 have issued a link-down signal indicating the occurrence of an abnormality, it determines that an abnormality has occurred and identifies the link 3 between those nodes 2 as the link 3 whose connection status has changed as the location of the abnormality. For example, FIG. 8 shows a case where nodes 2e and 2i are issuing link-down signals. In node 2i, the routing table 5 has been updated based on the change in the connection status. Link 3k, which is located between node 2e and node 2i and is connected to node 2i and located upstream on path 4 to which node 2i belongs, is identified as the link 3 whose connection state has changed. Based on the path table 5 of the changed node 2i, the path acquisition means 102 of the management server 1 updates path 4 to reflect the changes.

[0042] The management server 1 that receives the notification acquires status and routing table 5 information from the node 2 that sent the notification and from nodes 2 that are farther away from this node 2, in other words, downstream. In other words, the management server 1 updates the route 4 based on the acquired routing table 5. At this time, the management server 1 may diagnose a fault based on the acquired status information. The management server 1 holds tree structure information based on connections, and reacquires information and routing table 5 from the node 2 that sent the link-down signal and from nodes 2 that are farther away from the node 2 that sent the change notification, in other words, downstream.

[0043] The method of determining a multi-hop network route executed by the management server 1 will be described in more detail with reference to FIGS.

[0044] As shown in FIG. 4, multi-hop network 100 has nodes 2 and links 3, and information about each node 2 is transferred to management server 1 via path 4, which has a tree structure. Management server 1 determines path 4 based on a path table 5 held by each node 2 and stores it in storage unit 18. A case where link 3k is down or disconnected as shown in FIG. 5 will be described. Nodes 2e and 2i, which are in a link-down state, transmit link-down signals to management server 1. In management server 1, status change acquisition means 103 receives this link-down signal, which triggers node status acquisition means 101 to acquire path table 5 from the corresponding node 2. Here, node 2i detects link-down, but because link 3k is unavailable, it cannot transmit a link-down signal to management server 1 via path 4a at this point.

[0045] As shown in Figure 6, node 2 autonomously constructs route 4 to management server 1. At this point, route 4 from node 2i to management server 1 has also been reconstructed, and the status change acquisition means 103 of management server 1 receives link down signals from nodes 2e and 2i. If the status change acquisition means 103 determines that an abnormality has occurred based on the received link down signal, it identifies the location where the abnormality has occurred as link 3k. Because a link down signal indicates a link break, in this case, management server 1 can determine that link 3k is broken.

[0046] The node status acquisition means 101 acquires the status of the node 2 that issued the link down signal and the node 2 that exists downstream of link 3k as viewed from the management server 1, on the path 4a to which link 3k belongs. In Fig. 5, the node status acquisition means 101 acquires the status of nodes 2e, 2i, 2m, 2n, 2o, and 2p, specifically, the path tables 5 that these nodes 2 have. The nodes 2 whose statuses are acquired are surrounded by dashed lines in Fig. 5. The path acquisition means 102 of the management server 1 acquires a new path 4 shown in Fig. 6 based on the path tables 5 of these nodes 2e, 2i, 2m, 2n, 2o, and 2p.

[0047] 7 and 8 show changes in route 4 and route table 5 for the area indicated by the dashed line in FIG. 4 before and after the occurrence of the above-mentioned abnormality. The route acquisition means 102 of the management server 1 recognizes routes 4a and 4b based on the route table 5 shown in FIG. 7. When an abnormality occurs in link 3k, the route table 5 changes as shown in FIG. 8. The node status acquisition means 101 acquires the route table 5i of node 2i, which is on route 4a and located downstream from the management server 1 of the failed link 3k, and the route table 5e of node 2e, which has become linked down. Based on the route table 5i of node 2i, the route acquisition means 102 recognizes that a new route 4 shown in FIG. 8 has been constructed.

[0048] Returning to FIG. 5, the node status acquisition means 101 of the management server 1 acquires a routing table 5 similar to the routing table 5 shown in FIG. 8 from each node 2 (e.g., nodes 2e, 2i, 2m, 2n, 2o, and 2p) in the area surrounded by the dashed line in FIG. 5. Then, the route acquisition means 102 acquires a route 4 based on the newly acquired routing table 5. Then, the route acquisition means 102 grasps the entire newly constructed route 4 shown in FIG. 6. The management server 1 can grasp the routes 4 for the entire multi-hop network 100 simply by acquiring the status or routing tables 5 of the six nodes 2 (nodes 2e, 2i, 2m, 2n, 2o, and 2p) within the dotted line shown in FIG. 5 out of the total 16 nodes 2 shown in FIG. 6.

[0049] (Variation 1) The above explanation shows a case where a problem occurs on link 3. The same applies when node 2 is unable to respond. A bypass mode is adopted, which bypasses node 2 where the problem is occurring. Node 2 where the problem is occurring is broken, so it cannot notify management server 1 of the fact that it is broken. Nodes 2 before and after node 2 on route 4 and adjacent node 2 to node 2 where the problem is occurring notify management server 1 that the adjacent node 2 has changed. Management server 1 is notified that a problem is occurring with node 2 in question. Status change acquisition means 103 of management server 1 (1) determines that something seems to be happening, (2) checks both before and after, and (3) determines that a failure has occurred.

[0050] (Variation 2) This disclosure has been limited to mesh networks. However, the communication management method according to this disclosure can also be applied to a daisy-chain network when a bypass connection is made. Bypass connection refers to connecting a node 2 by skipping the failed point, i.e., bypassing the failed point, when one of the nodes 2 or links 3 in the daisy chain fails. In this case, the status of the node 2 adjacent to the failed point and the node 2 farther from the failed point, or in other words, downstream in the daisy chain, is acquired.

[0051] (Variation 3) The above explanation mainly focuses on a multi-hop network communication management method. However, it is also possible to realize the multi-hop network communication management by using a communication management device and a program that causes a computer to execute the functions of the communication management device.

[0052] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. Furthermore, the above-described embodiments are intended to illustrate the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of the disclosure equivalent thereto are considered to be within the scope of the present invention.

[0053] The multi-hop network communication management method according to the embodiment described above provides the following advantages.

[0054] (1) The communication management device is a communication management device connected to a network 100 in which a plurality of nodes 2 are interconnected, and is equipped with a memory unit 18 that holds a route table 5 formed based on the number of communication hops to each of the plurality of nodes 2 for a route 4 to each node 2 in the network 100, and a control unit 10 that, when an abnormality is detected at any node 2, refers to the route table 5 and performs communication to acquire status with the node 2 that notified the occurrence of the abnormality and with a node 2 located downstream on the route 4 to which the node 2 that notified the occurrence of the abnormality belongs.

[0055] This means that the management server 1, which is a communication management device, does not need to re-acquire information about all nodes 2. By reducing the number of nodes 2 whose status needs to be acquired to update the mesh network, the required time and communication volume can be reduced. This makes it possible to reduce the communication volume when the management server 1 acquires the connection status within the network.

[0056] (2) In the communication management device of (1), the control unit 10 identifies the location of the abnormality in the network 100 based on which node 2 has notified the occurrence of the abnormality.

[0057] As a result, the notification of the occurrence of an abnormality triggers the operation of the management server 1. Based on the information from the node 2 that notifies the occurrence of an abnormality, the state of the entire network can be grasped.

[0058] (3) In the communication management device of (2), the control unit 10 acquires the route 4 created after the occurrence of the abnormality based on the acquired abnormality location.

[0059] As a result, when the next abnormality occurs, the management server 1 can grasp the route 4 to which the link 3 in which the abnormality occurs belongs.

[0060] (4) In the communication management device of (1) to (3), the control unit 10 acquires the routing table 5 of the node 2 that notified the occurrence of the abnormality and the node 2 connected downstream of the node 2 that notified the occurrence of the abnormality.

[0061] As a result, the management server 1 can grasp the connection state between the nodes 2 based on the acquired routing table 5, and can grasp the entire network 100.

[0062] (5) The communication management method is a communication management method in a network 100 in which a plurality of nodes 2 are interconnected, in which a communication management device connected to the network holds a route 4 to each node 2 in the network 100 as a route table 5 formed based on the number of communication hops to each of the plurality of nodes 2, and when an abnormality is detected in any node 2, communication for obtaining status is performed on the route 4 to which the node 2 that notified the occurrence of the abnormality belongs, to the node 2 that notified the occurrence of the abnormality and to a node 2 located downstream on the route from the node 2 that notified the occurrence of the abnormality.

[0063] This means that the management server 1, which is a communication management device, does not need to re-acquire information about all nodes 2. By reducing the number of nodes 2 whose status needs to be acquired to update the mesh network, the required time and communication volume can be reduced. This makes it possible to reduce the communication volume when the management server 1 acquires the connection status within the network.

[0064] (6) The program causes a communication management device connected to a network in which multiple nodes 2 are interconnected to retain a route 4 to each node 2 in the network as a route table 5 formed based on the number of communication hops to each of the multiple nodes 2, and when an abnormality is detected in any node 2, causes the program to execute communication to obtain status on the route 4 to which the node 2 that notified the occurrence of the abnormality belongs, to the node 2 that notified the occurrence of the abnormality and to a node 2 located downstream on the route from the node 2 that notified the occurrence of the abnormality.

[0065] This means that the management server 1, which is a communication management device, does not need to re-acquire information about all nodes 2. By reducing the number of nodes 2 whose status needs to be acquired to update the mesh network, the required time and communication volume can be reduced. This makes it possible to reduce the communication volume when the management server 1 acquires the connection status within the network. [Explanation of symbols]

[0066] 1 Management Server 2 nodes 3. Links 4 Routes 5 Routing Table 10 Control Unit 11 processors 12 ROM 13 RAM 14 Bus 15 Input / Output Interface 16 Input / output section 17. Means of communication 18 Memory section 100 Multi-hop Networks 101 Node status acquisition means 102 Route acquisition method 103 Status change acquisition means

Claims

1. A communication management device connected to a network in which a plurality of nodes are interconnected, a storage unit that holds a routing table formed based on the number of communication hops to each of the plurality of nodes for a route to each of the nodes in the network; a control unit that, when an abnormality is detected in any of the nodes, refers to the routing table and executes communication for acquiring status with the node that notified the occurrence of the abnormality and with nodes located downstream of the node that notified the occurrence of the abnormality on the route to which the node belongs; Equipped with When an abnormality occurs in any of the nodes, the control unit acquires from the other node the routing table created by the other node adjacent to the node in which the abnormality occurs, regarding a route that bypasses the node in which the abnormality occurs. Communication management device.

2. The communication management device according to claim 1 , wherein the control unit identifies a location in the network where the abnormality has occurred based on which of the nodes has notified the occurrence of the abnormality.

3. The communication management device according to claim 2 , wherein the control unit acquires the route created after the occurrence of the abnormality based on the acquired location of the abnormality.

4. 3. The communication management device according to claim 1, wherein the control unit acquires the routing tables of the node that notified the occurrence of the abnormality and the nodes that are connected downstream of the notified node.

5. A communication management method in a network in which a plurality of nodes are interconnected, comprising: a communication management device connected to the network, a route table is maintained that contains a route to each of the nodes in the network, the route table being formed based on the number of communication hops to each of the plurality of nodes; When an abnormality is detected in any of the nodes, the communication management device executes communication for acquiring status to the node that notified the occurrence of the abnormality and to a node located downstream on the path to which the node that notified the occurrence of the abnormality belongs, When an abnormality occurs in any of the nodes, the routing table for a route that bypasses the node where the abnormality occurs, which is created by another node adjacent to the node where the abnormality occurs, is acquired from the other node. Communication management methods.

6. A communication management device connected to a network in which a plurality of nodes are interconnected, maintaining a route to each of the nodes in the network as a route table formed based on the number of communication hops to each of the plurality of nodes; When an abnormality is detected in any of the nodes, the node that notified the occurrence of the abnormality executes communication for acquiring a status on the path to which the node that notified the occurrence of the abnormality belongs, to the node that notified the occurrence of the abnormality and to the node that is located downstream on the path from the node that notified the occurrence of the abnormality; When an abnormality occurs in any of the nodes, the routing table for a route that bypasses the node where the abnormality occurs, which is created by another node adjacent to the node where the abnormality occurs, is acquired from the other node. program.

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