Control device and control method

Abstract

A control device comprising a threshold calculating unit that calculates a signal strength threshold to be set for each port of at least one controlled device, and that instructs the at least one controlled device, which is to be subjected to setting, to set the calculated signal strength threshold, which is calculated on the basis of information that indicates a minimum value of a signal transmission strength for any one of a plurality of terminal devices that perform communication, or information that indicates the signal strength of each port of the at least one controlled device which a signal transmitted between the plurality of terminal devices goes through when the plurality of terminal devices is first connected.　

Description

Control device and control method

[0001] The present invention relates to a control device and a control method.

[0002] Conventionally, a communication system has been proposed that performs path control between terminal devices, as shown in Fig. 22. Fig. 22 is a diagram showing an example of the configuration of a conventional communication system S. The communication system S includes a plurality of terminal devices #1 and #2, a plurality of control target devices #1 to #3, and a control device. The terminal device #1 and the terminal device #2 transmit or receive communication data via any of the control target devices #1 to #3. The control target devices #1 to #3 are installed between the terminal devices #1 and #2, and perform path control of the communication data of the terminal devices #1 and #2 in the communication network.

[0003] For example, the control target devices #1 to #3 each have multiple ports, and change the route by switching the connection path between the ports. The control device controls the route settings of the control target devices #1 to #3. The control device changes the route taken by communication data between terminal devices #1 and #2 by controlling the route settings of one or more of the control target devices #1 to #3. Note that, although one control device controls multiple control target devices #1 to #3 in FIG. 22, a control device may be provided for each of the control target devices #1 to #3.

[0004] T. Suzuki et al., “Automatic fast failure restoration on software-defined optical switch controller with NETCONF / RESTCONF for all-photonics network”, IEICE Communications Express, 2022, Volume 11, Issue 11, Pages 709-714.

[0005] In such a communication system S, the control device constantly monitors the signal strength of each port of the control target devices #1 to #3, and when the signal strength falls below a preset threshold, it recognizes that a failure has occurred in the signal line or the control target devices #1 to #3, and can continue communication by switching the path setting of the control target devices #1 to #3. Figure 22 shows a situation in which terminal device #1 is communicating with terminal device #2 via a signal path that passes through control target devices #1 and #2, and the control device switches to a signal path that passes through control target devices #1 to #3.

[0006] In such a communication system S, it is necessary to manually set the thresholds for each port of the controlled devices #1 to #3 in advance, but if there are a large number of controlled devices or a large number of ports on the controlled devices, the threshold setting process becomes very complicated and takes a huge amount of time.

[0007] In view of the above circumstances, an object of the present invention is to provide a technique that can simplify the threshold setting work and reduce the time required for threshold setting.

[0008] One aspect of the present invention is a control device that includes a threshold calculation unit that calculates a signal strength threshold to be set for each port of at least one of a plurality of controlled devices based on information indicating a lower limit value of the signal transmission strength of one of a plurality of terminal devices that communicate, or information indicating the signal strength of each port of one or more controlled devices through which signals sent and received between the plurality of terminal devices pass at the time of initial connection of the plurality of terminal devices, and instructs the one or more controlled devices that are the setting targets to set the calculated signal strength threshold.

[0009] One aspect of the present invention is a control method that acquires information indicating a lower limit value of the signal transmission strength of one of multiple terminal devices communicating with each other, or information indicating the signal strength of each port of one or more controlled devices through which signals sent and received between the multiple terminal devices at the time of initial connection of the multiple terminal devices, calculates a signal strength threshold to be set for each port of at least the one or more controlled devices based on the acquired information indicating the lower limit value of the signal transmission strength or the information indicating the signal strength, and instructs the one or more controlled devices to set the calculated signal strength threshold.

[0010] According to the present invention, it is possible to simplify the threshold setting work and reduce the time required for threshold setting.

[0011] 1 is a diagram for explaining an overview of a communication system in the present invention. FIG. 1 is a diagram illustrating an example of a configuration of a communication system in a first embodiment. FIG. 2 is a diagram illustrating an example of a configuration of a terminal device, a controlled device, and a control device in the first embodiment. FIG. 3 is a diagram illustrating an example of a device / line management list in the first embodiment. FIG. 4 is a diagram illustrating an example of a connection relationship list in the first embodiment. FIG. 5 is a diagram illustrating an example of threshold calculation in the first embodiment. FIG. 6 is a flowchart illustrating the flow of threshold setting processing performed by the control device in the first embodiment. FIG. 7 is a diagram illustrating an example of a threshold calculation list in the first embodiment. FIG. 8 is a flowchart illustrating the flow of threshold resetting processing performed by the control device in the first embodiment. FIG. 9 is a diagram illustrating an example of a threshold calculation list after path switching in the first embodiment. FIG. 10 is a sequence diagram illustrating the flow of processing performed by a communication system in the first embodiment. FIG. 11 is a diagram illustrating an example of a configuration of a communication system in a second embodiment. FIG. 12 is a diagram illustrating an example of a configuration of a terminal device, a controlled device, and a control device in the second embodiment. FIG. 13 is a diagram illustrating an example of a device / line management list in the second embodiment. FIG. 14 is a diagram illustrating an example of a connection relationship list in the second embodiment. FIG. 15 is a diagram illustrating an example of a threshold calculation list after path switching in the second embodiment. FIG. 16 is a diagram illustrating an example of a device / line management list in a third embodiment. FIG. 17 is a flowchart illustrating the flow of threshold setting processing performed by the control device in the third embodiment. FIG. 18 is a diagram illustrating an example of a threshold calculation list in the third embodiment. Fig. 10 is a diagram illustrating an example of a threshold calculation list after route switching in the third embodiment. Fig. 11 is a diagram illustrating an example of the configuration of a conventional communication system.

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] (Overview) First, an overview of the present invention will be described using Fig. 1. Fig. 1 is a diagram for explaining an overview of a communication system 1000 according to the present invention. In the communication system 1000 according to the present invention, a signal strength threshold is automatically set for each port through which signals communicated between terminal devices pass. This simplifies the threshold setting process and reduces the time required for threshold setting.

[0014] The communication system 1000 includes a plurality of terminal devices 100-1 to 100-2, a plurality of control target devices 200-1 to 200-3, a control device 300, a device / line management DB 410, a topology DB 420, and a higher-level device 430. In the following explanation, an example will be described in which there are two terminal devices 100 and three control target devices 200, but the number of terminal devices 100 and control target devices 200 is not particularly limited as long as there are multiple terminal devices 100 and control target devices 200.

[0015] A plurality of control target devices 200-1 to 200-3 are provided between a plurality of terminal devices 100-1 to 100-2. Each control target device 200 sets a route in response to an instruction from the control device 300, and forwards a signal transmitted from the terminal device 100-1 or 100-2 to the destination. Hereinafter, the route connecting the terminal device 100-1 and the terminal device 100-2 will be referred to as a signal route.

[0016] In each control target device 200, a signal strength threshold is set for each port to detect abnormalities in the lines that make up the signal path. Conventionally, thresholds were set manually, which made the threshold setting process extremely cumbersome and time-consuming when there were a large number of control target devices and a large number of ports in each control target device. In contrast, the present invention automatically calculates and sets the signal strength threshold for at least each port of each control target device 200 using either the first or second method described below.

[0017] (Outline of First Method) In the first method, the control device 300 automatically calculates and sets a signal strength threshold for each port of at least each control target device 200, based on the device / line management list stored in the device / line management DB 410 and the connection relationship list stored in the topology DB 420, using the lower limit value of the signal transmission strength of the terminal device 100 as a reference. Note that the control device 300 may also automatically calculate and set a signal strength threshold for each port of the terminal device 100.

[0018] The connection relationship list is a list in which information regarding the connection relationship for each signal path connecting the terminal devices 100 is registered. As shown in Fig. 1, the signal paths connecting the terminal devices 100 include a signal path that passes through the control target devices 200-1 and 200-2 (for example, terminal device 100-1 ⇒ control target device 200-1 ⇒ control target device 200-2 ⇒ terminal device 100-2) and a signal path that passes through the control target devices 200-1, 200-3, and 200-2 (for example, terminal device 100-1 ⇒ control target device 200-1 ⇒ control target device 200-3 ⇒ control target device 200-2 ⇒ terminal device 100-2). Information regarding the connection relationship for each of these signal paths is registered in the connection relationship list.

[0019] The device / line management list is a list in which information about each line constituting a signal path connecting terminal devices 100 is registered. Each line constituting a signal path represents a section connecting devices in the signal path or a section connecting ports within a device. For example, in the example shown in FIG. 1, the section between terminal device 100-1 and control target device 200-1 is one line, and the section between ports within control target device 200-1 is also one line. Furthermore, information about each line is, for example, loss in the line (e.g., insertion loss, transmission loss), transmission distance, or delay time. Here, loss in a section connecting devices in a signal path is transmission loss, and loss in a section connecting ports within a device is insertion loss.

[0020] The flow of the first method will be described. The explanation is based on the premise that the initial connection between the terminal devices 100 has been completed. (Step 1) The control device 300 acquires the lower limit value of the signal transmission strength of the terminal device 100 notified by the higher-level device 430. (Step 2) The control device 300 refers to the topology DB 420 and identifies ports and lines that can transmit and receive signals between the control target device 200 and the terminal device 100 between the terminal devices 100.

[0021] (Procedure 3) The control device 300 refers to the device / line management DB 410, acquires the transmission loss (or transmission distance, delay time) of each line and the insertion loss of the control target device 200, and automatically calculates the signal strength threshold of each port of the control target device 200 through which signals are transmitted and received, based on the lower limit value of the signal transmission strength of the terminal device 100 acquired in (Procedure 1). (Procedure 4) The control device 300 transmits the threshold calculated in (Procedure 3) to the control target device 200, and causes the control target device 200 to set the signal strength threshold of each port.

[0022] (Summary of the second method) In the second method, the control device 300 automatically calculates and sets the signal strength threshold for each port of at least each controlled device 200 based on the device / line management list stored in the device / line management DB 410 and the connection relationship list stored in the topology DB 420, using the signal strength of each port at the time of initial connection between the terminal devices 100 as a reference value.

[0023] The flow of the second technique will be described. In this description, it is assumed that the initial connection between the terminal devices 100 has been completed. (Step 1) The control device 300 references the device / line management DB 410 and acquires, as a reference value, the signal strength of each port in each control-target device 200 when the terminal devices 100 are initially connected. (Step 2) The control device 300 automatically calculates a threshold value by subtracting an arbitrary value from the reference value. At this time, the arbitrary value may be the same value or may be different for each port. (Step 3) The control device 300 transmits the threshold value calculated in (Step 2) to the control-target device 200, causing the control-target device 200 to set the signal strength threshold value for each port.

[0024] As described above, in the present invention, either the first method or the second method is used to calculate and set the signal strength threshold for at least each port of each control-target device 200. This simplifies the task of setting the threshold for each port and reduces the time required for setting, even when there are a large number of control-target devices 200 or a large number of ports provided in the control-target devices 200. A specific configuration using the above-described methods will be described below.

[0025] 2 is a diagram illustrating an example of the configuration of a communication system 1000 according to the first embodiment. In the communication system 1000 according to the first embodiment, thresholds are automatically set for ports of each control target device 200 through which signals communicated between terminal devices pass, based on a first technique. This simplifies the threshold setting process and reduces the time required for threshold setting.

[0026] The communication system 1000 includes a plurality of terminal devices 100-1 to 100-2, a plurality of control target devices 200-1 to 200-3, a control device 300, a device / line management DB 410, a topology DB 420, and a higher-level device 430. In the following explanation, an example will be described in which there are two terminal devices 100 and three control target devices 200, but the number of terminal devices 100 and control target devices 200 is not particularly limited as long as there are multiple terminal devices 100 and control target devices 200.

[0027] A terminal device 100 transmits or receives communication data to or from other terminal devices 100 via any one of the control target devices 200. In the example shown in Fig. 2, the terminal device 100-1 transmits or receives communication data to or from the terminal device 100-2 via the control target device 200-1 and the control target device 200-2, or via the control target device 200-1, the control target device 200-3, and the control target device 200-2.

[0028] The terminal device 100 has one or more ports. The terminal device 100-1 has, for example, port 1-1. The port 1-1 of the terminal device 100-1 is connected to any of the ports of the control target device 200-1. The terminal device 100-2 has, for example, port 2-1. The port 2-1 of the terminal device 100-2 is connected to any of the ports of the control target device 200-2. The terminal device 100 constantly monitors the signal strength of signals input to the ports. The terminal device 100 notifies the control device 300 of the monitoring results.

[0029] The control target device 200 is installed between a plurality of terminal devices 100 that communicate with each other. In FIG. 2, the control target device 200 is installed between terminal device 100-1 and terminal device 100-2. The control target device 200 has a plurality of ports and performs routing control of communication data of the terminal devices 100. The control target device 200-1 has, for example, N (N is an integer of 2 or more) first ports 11 and N second ports 12. The control target device 200-2 has, for example, N first ports 21 and N second ports 22. The control target device 200-3 has, for example, N first ports 31 and N second ports 32.

[0030] 2 shows a configuration in which all of the control-target devices 200 have the same number of ports, but the number of ports that each control-target device 200 has may be different. Furthermore, the number of first ports and second ports that each control-target device 200 has may also be different.

[0031] Furthermore, the control target device 200 sets a signal strength threshold for each port in response to instructions sent from the control device 300. Furthermore, the control target device 200 constantly monitors the signal strength of signals input to the first port or the second port. The control target device 200 notifies the control device 300 of the monitoring results. Furthermore, the control target device 200 sets a route for transferring the input signal in response to instructions from the control device 300.

[0032] The control device 300 calculates the signal strength threshold of each port of each controlled device 200 based on information indicating the lower limit value of the terminal device 100 notified from the higher-level device 430, the device / line management list stored in the device / line management DB 410, and the connection relationship list stored in the topology DB 420.

[0033] Furthermore, the control device 300 performs route control for each control-target device 200 as necessary. For example, if an abnormality occurs in a section of a signal path, the control device 300 performs route control for the control-target device 200 related to the section where the abnormality occurred. The control device 300 changes the transfer route of communication data between the terminal devices 100 by controlling the route settings of one or more control-target devices 200. This allows the control device 300 to continue communication. Note that while FIG. 2 shows a configuration in which one control device 300 controls multiple control-target devices 200, a control device 300 may be provided for each control-target device 200.

[0034] The equipment / line management DB 410 stores an equipment / line management list. The equipment / line management DB 410 is configured using a storage device such as a magnetic storage device or a semiconductor storage device. In response to a request from the control device 300, the equipment / line management DB 410 provides the stored equipment / line management list to the control device 300.

[0035] The topology DB 420 stores a connection relationship list. The topology DB 420 is configured using a storage device such as a magnetic storage device or a semiconductor storage device. In response to a request from the control device 300, the topology DB 420 provides the stored connection relationship list to the control device 300.

[0036] The higher-level device 430 provides the control device 300 with a lower limit value of the signal transmission strength of the terminal device 100 that is to perform communication.

[0037] The following explanation assumes the state shown in Fig. 2. Note that Fig. 2 shows specific numerical values ​​to clearly explain the contents of the present invention, but these numerical values ​​are merely examples. Port 1-1 of terminal device 100-1 and port 11-1 of control target device 200-1 are connected, the distance of line a connecting port 1-1 and port 11-1 is 10 km, and the transmission loss of line a is 2 dB. Port 2-1 of terminal device 100-2 and port 22-1 of control target device 200-2 are connected, the distance of line e connecting port 2-1 and port 22-1 is 10 km, and the transmission loss of line e is 2 dB.

[0038] Port 12-1 of control target device 200-1 and port 21-1 of control target device 200-2 are connected, the distance of line c connecting port 12-1 and port 21-1 is 10 km, and the transmission loss of line c is 4 dB. Port 12-N of control target device 200-1 and port 31-1 of control target device 200-3 are connected, the distance of line g connecting port 12-N and port 31-1 is 10 km, and the transmission loss of line g is 2 dB. Port 32-1 of control target device 200-3 and port 21-N of control target device 200-2 are connected, the distance of line i connecting port 32-1 and port 21-N is 10 km, and the transmission loss of line a is 2 dB.

[0039] 3 is a diagram showing an example of the configuration of the terminal device 100, the control target device 200, and the control device 300 in the first embodiment. The configurations of the terminal device 100, the control target device 200, and the control device 300 will be described below.

[0040] [Configuration of Terminal Device 100] The terminal device 100 includes a signal strength monitoring unit 110. The signal strength monitoring unit 110 monitors the strength of signals input to ports of the terminal device 100. The signal strength monitoring unit 110 notifies the control device 300 of the monitoring result via interface D. For example, if the signal strength is equal to or greater than a threshold, the signal strength monitoring unit 110 notifies the control device 300 that the communication situation is normal as the monitoring result. On the other hand, if the signal strength is less than the threshold, the signal strength monitoring unit 110 notifies the control device 300 of the occurrence of an abnormality (the signal strength is less than the threshold) and the value of the signal strength as the monitoring result. Note that the signal strength monitoring unit 110 may notify the control device 300 of the monitoring result only if the signal strength falls below the threshold.

[0041] [Configuration of Control Target Device 200] The control target device 200 includes a threshold setting unit 210, a signal strength monitoring unit 220, and a route setting unit 230. The threshold setting unit 210 acquires thresholds related to the signal strength of each port notified by the control device 300. The threshold setting unit 210 sets the acquired thresholds for the corresponding ports. If a threshold has already been set for the port for which the threshold is to be set, the threshold setting unit 210 sets the threshold by overwriting the previously set threshold with the newly acquired threshold.

[0042] The signal strength monitoring unit 220 monitors the strength of signals input to ports of the control target device 200. The signal strength monitoring unit 220 notifies the control device 300 of the monitoring result via interface C. For example, if the signal strength is equal to or greater than a threshold, the signal strength monitoring unit 220 notifies the control device 300 that the communication status is normal as the monitoring result. On the other hand, if the signal strength is less than the threshold, for example, the signal strength monitoring unit 220 notifies the control device 300 of the occurrence of an abnormality (the signal strength is less than the threshold) and the value of the signal strength as the monitoring result. Note that the signal strength monitoring unit 220 may notify the control device 300 of the monitoring result only if the signal strength falls below the threshold.

[0043] The route setting unit 230 sets a route in accordance with an instruction from the control device 300. The route setting unit 230 switches the connection relationship between ports so that a signal can be transferred along the route instructed by the control device 300, for example.

[0044] [Configuration of control device 300] The control device 300 includes a threshold calculation unit 310, an analysis unit 320, and a route control unit 330. The threshold calculation unit 310 calculates the signal strength threshold of each port of each control-target device 200 through which signals communicated between terminal device 100-1 and terminal device 100-2 pass, based on the device / line management list provided by the device / line management DB 410, the connection relationship list provided by the topology DB 420, and the lower limit value of the signal transmission strength of the terminal device 100 notified by the higher-level device 430. The threshold calculation unit 310 notifies each control-target device 200 of the calculated signal strength threshold of each port of each control-target device 200 via interface A.

[0045] As described above, the threshold calculation unit 310 calculates the signal strength threshold of each port of each control target device 200 through which the signal communicated between the terminal device 100-1 and the terminal device 100-2 passes. Therefore, there may be some control target devices 200 for which the signal strength threshold of a port cannot be calculated, depending on the route the signal passes through.

[0046] The analysis unit 320 acquires monitoring results from the terminal device 100 and the control target device 200. Note that the analysis unit 320 in the first embodiment uses the monitoring results acquired from the control target device 200. The analysis unit 320 monitors signals at each port of each control target device 200. The analysis unit 320 determines whether or not it is necessary to change the path setting of the control target device 200 based on the monitoring results notified from each control target device 200. If an abnormality has occurred in some sections of the signal path, the analysis unit 320 determines that it is necessary to change the path setting of the control target device 200. On the other hand, if no abnormality has occurred in any sections of the signal path, the analysis unit 320 determines that it is not necessary to change the path setting of the control target device 200.

[0047] Whether or not an abnormality has occurred can be determined based on the monitoring results notified from each control-target device 200. When it is necessary to change the route setting of the control-target device 200, the analysis unit 320 identifies the route on which the abnormality has occurred (hereinafter referred to as the "abnormal route") based on the monitoring results notified from each control-target device 200. Furthermore, the analysis unit 320 searches for a detour route excluding the abnormal route as a new signal route. Here, the detour route is a route that allows communication between the terminal device 100-1 and the terminal device 100-2 to continue, and is a route excluding the abnormal route. If a new signal route is found, the analysis unit 320 decides to switch to the new signal route. If a new signal route is not found, the analysis unit 320 may stop communication.

[0048] When the analysis unit 320 determines that the path setting of the control-target device 200 needs to be changed, the path control unit 330 instructs the control-target device 200 that needs path setting to change the path setting. Specifically, the path control unit 330 instructs the control-target device 200 that needs path setting to switch the connection relationship between ports via the interface F so as to form the new signal path determined by the analysis unit 320. This enables the path control unit 330 to switch the path for the control-target device 200.

[0049] [Details of the Equipment and Line Management List] Figure 4 is a diagram showing an example of the equipment and line management list in the first embodiment. The equipment and line management list has multiple records representing information about each line that constitutes the signal path connecting the terminal device 100-1 and the terminal device 100-2. Each record has an item number, line, section (start point), section (end point), and loss value. The item number represents an identification number for identifying the record number. The line represents information assigned to uniquely identify the route of a certain section of the signal path. The section (start point) represents the port that is the start point of the line. The section (end point) represents the port that is the end point of the line. The loss represents the loss that occurs on the corresponding line.

[0050] 4, item number "1" has registered therein information indicating "a" as the line, information indicating "1-1" as the section (start point), information indicating "11-1" as the section (end point), and information indicating "2" as the loss. That is, item number "1" indicates that a portion of the signal path connecting terminal device 100-1 and terminal device 100-2 is line "a," line "a" is the path connecting port "1-1" and port "11-1," and a signal loss of "2 dB" occurs.

[0051] Port "1-1" is a port that the terminal device 100-1 has, and port "11-1" is a port that the control target device 200-1 has. In this way, line "a" is a path that connects the terminal device 100-1 and the control target device 200-1.

[0052] 4, item number "2" has registered therein information indicating "b (control target device 200-1)" as the line, information indicating "11-1" as the section (start point), information indicating "12-1" as the section (end point), and information indicating "5" as the loss. That is, item number "2" indicates that a portion of the signal path connecting terminal device 100-1 and terminal device 100-2 is line "b," line "b" is the path connecting port "11-1" and port "12-1," and a signal loss of "5 dB" occurs.

[0053] Port "11-1" is the first port of the control target device 200-1, and port "12-1" is the second port of the control target device 200-1. In this way, line "b" is a path connecting the inside of the control target device 200.

[0054] As described above, the equipment and line management list registers information about each of the sections of the signal path connecting the terminal unit 100-1 and the terminal unit 100-2.

[0055] The transmission distances of each signal line may be listed. In this case, an average transmission loss value per unit length of the signal line, such as 0.2 dB / km, is used, and the list is created by converting the value into the transmission loss for the transmission distance.

[0056] [Details of the Connection Relationship List] Fig. 5 is a diagram showing an example of the connection relationship list in the first embodiment. The connection relationship list has multiple records representing information about the connection relationship for each signal path connecting the terminal device 100-1 and the terminal device 100-2. Depending on the connection relationship, there may be multiple signal paths connecting the terminal device 100-1 and the terminal device 100-2. Therefore, the connection relationship list registers the connection relationships of all possible signal paths.

[0057] Each record has values ​​of an item number, an end point A, a line or a controlled device, and an end point B. The item number represents an identification number for identifying the record number. End point A represents the device that is the starting point of the signal path. The line or controlled device represents the line or the controlled device 200 that is passed through on the way from end point A to end point B. End point B represents the device that is the starting point of the signal path.

[0058] In the example shown in Figure 5, item number "1" has registered therein information indicating "terminal device 100-1 (1-1)" as endpoint A, information indicating "line a, controlled device 200-1 (11-1), line b, controlled device 200-1 (12-1), line c, controlled device 200-2 (21-1), line d, controlled device 200-2 (22-1), line e" as the line or controlled device, and information indicating "terminal device 100-2 (2-1)" as endpoint B. That is, item number "1" indicates that the signal path connecting endpoint A and endpoint B passes through "line a, controlled device 200-1 (11-1), line b, controlled device 200-1 (12-1), line c, controlled device 200-2 (21-1), line d, controlled device 200-2 (22-1), and line e."

[0059] [Details of Threshold Calculation List] Fig. 6 is a diagram showing an example of threshold calculation in the first embodiment. The threshold calculation list has multiple records representing information on the thresholds of each port of each control target device 200 calculated by the threshold calculation unit 310. Each record has an item number, a port, and a threshold value. The item number represents an identification number for identifying the signal path registered in the record. The port represents a port of the control target device 200. The threshold represents the signal strength threshold calculated by the threshold calculation unit 310.

[0060] [Threshold Setting Process] Fig. 7 is a flowchart showing the flow of the threshold setting process performed by the control device 300 in the first embodiment. Note that the process in Fig. 7 will be described taking as an example a case where the signal path is configured with the connection relationship registered in item number "1" in the connection relationship list shown in Fig. 5. That is, the initial connection state in the process in Fig. 7 is assumed to be a state in which the terminal device 100-1 and the terminal device 100-2 are connected by a signal line (for example, line a ⇒ line b ⇒ line c ⇒ line d ⇒ line e) that passes through the control target devices 300-1 and 300-2, as shown in Fig. 2.

[0061] The threshold calculation unit 310 acquires information about the lower limit value (e.g., 0 dBm) of the signal transmission strength of the terminal device 100-1 notified by the higher-level device 430 via interface X (step S101). Note that the terminal device 100-1 and the terminal device 100-2 have the same lower limit value of the signal transmission strength. Therefore, the threshold calculation unit 310 may acquire information about the lower limit value of the signal transmission strength from the terminal device 100-2.

[0062] Furthermore, at least terminal device 100-1 or 100-2 (including both terminal device 100-1 and 100-2) may notify the control device 300 of information on the lower limit value of the signal transmission strength of its own device. Furthermore, the control device 300 may request at least terminal device 100-1 or 100-2 (including both terminal device 100-1 and 100-2) to notify the lower limit value of the signal transmission strength.

[0063] The threshold calculation unit 310 requests the topology DB 420 to provide a connection relationship list relating to signal paths connecting the terminal devices 100 via interface G. In response, the threshold calculation unit 310 acquires the connection relationship list from the topology DB 420 via interface H (step S102). Note that the connection relationship list acquired by the threshold calculation unit 310 here is the record corresponding to item number "1," which is the state at the time of initial connection.

[0064] Next, in order to check the loss of each line and the control target device 200 described in the record corresponding to item number "1" in the acquired connection relationship list, the threshold calculation unit 310 requests the device / line management DB 410 to provide the device / line management list via interface I. For example, the threshold calculation unit 310 may request the provision of the device / line management list by transmitting to the device / line management DB 410 "line a, control target device 200-1 (11-1), line b, control target device 200-1 (12-1), line c, control target device 200-2 (21-1), line d, control target device 200-2 (22-1), line e" described in the line or control target device item of the record corresponding to item number "1".

[0065] As a result, the threshold calculation unit 310 acquires an equipment / line management list from the equipment / line management DB 410 via the interface J (step S103). Note that the equipment / line management list acquired by the threshold calculation unit 310 here is the record corresponding to item numbers "1" to "5". As a result, the threshold calculation unit 310 acquires information on the transmission loss of line a of "2 dB", the loss of line b (equivalent to the insertion loss of the controlled device 200-1) of "5 dB", the transmission loss of line c of "4 dB", the loss of line d (equivalent to the insertion loss of the controlled device 200-2) of "5 dB", and the transmission loss of line e of "2 dB".

[0066] The threshold calculation unit 310 calculates the threshold of each port of each control-target device 200 based on the acquired information (step S104). The threshold calculation unit 310 calculates, for example, the threshold of each of the first port 11-1 of the control-target device 200-1, the second port 12-1 of the control-target device 200-1, the first port 21-1 of the control-target device 200-2, and the second port 22-1 of the control-target device 200-2, which are included in the signal path. The method of calculating the threshold will be described below.

[0067] (Method of calculating threshold for first port 11-1 of controlled device 200-1) The threshold calculation unit 310 subtracts "2 dB", which is the loss (transmission loss) of line a, from the lower limit "0 dBm" of the signal transmission strength of the terminal device 100-1. As a result, the threshold calculation unit 310 calculates 0-2 = -2 dBm as the threshold for the first port 11-1 of the controlled device 200-1. In this way, the threshold calculation unit 310 calculates the threshold by subtracting the loss that occurs from the terminal device 100-1 to the port that is the target of threshold calculation, using the lower limit of the signal transmission strength of the terminal device 100-1 as a reference.

[0068] (Method of calculating threshold value of second port 12-1 of control target device 200-1) The threshold calculation unit 310 subtracts "2 dB" which is the loss (transmission loss) of line a and "5 dB" which is the loss of line b (equivalent to the insertion loss of the control target device 200-1) from the lower limit value "0 dBm" of the signal transmission strength of the terminal device 100-1. As a result, the threshold calculation unit 310 calculates 0 - 2 - 5 = -7 dBm as the threshold value of the second port 12-1 of the control target device 200-1.

[0069] (Method of calculating threshold for first port 21-1 of control target device 200-2) The threshold calculation unit 310 subtracts "2 dB" which is the loss (transmission loss) of line a, "5 dB" which is the loss of line b (equivalent to the insertion loss of the control target device 200-1), and "4 dB" which is the loss (transmission loss) of line c from the lower limit "0 dBm" of the signal transmission strength of the terminal device 100-1. As a result, the threshold calculation unit 310 calculates 0-2-5-4=-11 dBm as the threshold for the first port 21-1 of the control target device 200-2.

[0070] (Method of calculating threshold for second port 22-1 of control target device 200-2) The threshold calculation unit 310 subtracts "2 dB" which is the loss (transmission loss) of line a, "5 dB" which is the loss of line b (equivalent to the insertion loss of control target device 200-1), "4 dB" which is the loss (transmission loss) of line c, and "5 dB" which is the loss of line d (equivalent to the insertion loss of control target device 200-2) from the lower limit "0 dBm" of the signal transmission strength of the terminal device 100-1. As a result, the threshold calculation unit 310 calculates 0-2-5-4-5 = -16 dBm as the threshold for the second port 22-1 of the control target device 200-2.

[0071] The threshold calculation unit 310 saves each calculated threshold as a threshold calculation list as shown in FIG. 8. FIG. 8 is a diagram showing an example of a threshold calculation list. The threshold calculation list has multiple records that represent information about the threshold of each port calculated by the threshold calculation unit 310. Each record has an item number, a port, and a threshold value. The item number represents an identification number for identifying the record number. The port represents the port for which the threshold was calculated. The threshold represents the threshold calculated by the threshold calculation unit 310.

[0072] Thereafter, the threshold calculation unit 310 transmits a setting instruction including each threshold to the control-target device 200 to be set (step S105). The threshold calculation unit 310 transmits a setting instruction including a threshold of "-2 dBm" for the first port 11-1 and a threshold of "-7 dBm" for the second port 12-1 to the control-target device 200-1 via interface A. Furthermore, the threshold calculation unit 310 transmits a setting instruction including a threshold of "-11 dBm" for the first port 21-1 and a threshold of "-16 dBm" for the second port 22-1 to the control-target device 200-2 via interface A. This makes it possible to set thresholds for the control-target device 200 to be set as thresholds.

[0073] [Threshold resetting process] Figure 9 is a flowchart showing the flow of the threshold resetting process performed by the control device 300 in the first embodiment. The process shown in Figure 9 is executed after the threshold setting process shown in Figure 7 has been performed. Therefore, the connection state at the start of the process in Figure 9 is a state in which the terminal device 100a-1 and the terminal device 100a-2 are connected by a signal line that passes through the control target devices 300-1 and 300-2.

[0074] The analysis unit 320 periodically acquires monitoring results from each control target device 200 (step S201). The analysis unit 320 determines whether or not an abnormality has occurred based on the acquired monitoring results of each control target device 200 (step S202). If the analysis unit 320 determines that no abnormality has occurred (step S202-NO), the control device 300 ends the processing of FIG. 9.

[0075] On the other hand, if the analysis unit 320 determines that an abnormality has occurred (step S202-YES), the analysis unit 320 determines a new signal path (step S203). Here, for example, a case will be described in which, for the first port 21-1 (e.g., item 3 in FIG. 8) of the control target device 200-2, for which the threshold value is set to "-11 dBm," normal communication status has been reported up until that point, but at a certain point in time, an abnormality has occurred and a signal strength of "-35 dBm" that is significantly lower than the threshold is reported, resulting in a disconnection of communication between the terminal devices 100.

[0076] Because the analysis unit 320 has been notified by each control-target device 200 that the communication status for ports other than the first port 21-1 is normal, the analysis unit 320 determines that some kind of failure (such as a break in the signal line) has occurred between the second port 12-1 of the control-target device 200-1 and the first port 21-1 of the control-target device 200-2 (line c). If this continues, the communication interruption will continue, so the analysis unit 320 searches for a signal path that can bypass the faulty location (line c).

[0077] Then, it is assumed that the analysis unit 320 finds a new signal path that passes through the control target device 200-3 (item number N in FIG. 5). In this case, the analysis unit 320 decides to switch to the new signal path. The analysis unit 320 instructs the path control unit 330 to switch to the determined new signal path via interface E. In response to the instruction from the analysis unit 320, the path control unit 330 instructs the corresponding control target device 200 to switch paths via interface F (step S204).

[0078] Specifically, the route control unit 330 instructs the control target device 200-1 to switch the connection port of the first port 11-1 from the second port 12-1 to 12-N. The route control unit 330 also instructs the control target device 200-3 to set the connection port of the first port 31-1 to the second port 32-1. Furthermore, the route control unit 330 instructs the control target device 200-2 to switch the connection port of the first port 22-1 from the second port 21-1 to 21-N. Once these route settings are complete, the communication service between the terminal devices 100 can be restored using a new signal path that bypasses the line c where the failure occurred.

[0079] Note that even after the above-mentioned path switching, the control device 300 needs to automatically reset the threshold list in order to monitor the signals at each port. Therefore, in response to the path switching by the path control unit 330, the threshold calculation unit 310 requests the topology DB 420 to provide a connection relationship list related to the signal paths connecting the terminal devices 100 via interface G. In response to this, the threshold calculation unit 310 acquires the connection relationship list from the topology DB 420 via interface H (step S205). Note that the connection relationship list acquired by the threshold calculation unit 310 here is the record corresponding to item number "N," which is the state after the path switching.

[0080] Next, in order to check the losses of each line and the controlled device 200 described in the record corresponding to item number "N" in the acquired connection relationship list, the threshold calculation unit 310 requests the equipment / line management DB 410 to provide the equipment / line management list via interface I. For example, the threshold calculation unit 310 may request the equipment / line management list by sending information described in the line or controlled device item of the record corresponding to item number "N" to the equipment / line management DB 410.

[0081] As a result, the threshold calculation unit 310 acquires an equipment / line management list from the equipment / line management DB 410 via the interface J (step S206). Note that the equipment / line management list acquired by the threshold calculation unit 310 here is the record corresponding to item numbers "1", "5", and "6" to "10". As a result, the threshold calculation unit 310 acquires information on the transmission loss of line a of "2 dB", the loss of line f (equivalent to the insertion loss of the controlled device 200-1) of "5 dB", the transmission loss of line g of "2 dB", the loss of line h (equivalent to the insertion loss of the controlled device 200-3) of "5 dB", the transmission loss of line i of "2 dB", the loss of line j (equivalent to the insertion loss of the controlled device 200-2) of "5 dB", and the transmission loss of line e of "2 dB".

[0082] The threshold calculation unit 310 calculates the threshold of each port of each control-target device 200 based on the acquired information (step S207). The threshold calculation unit 310 calculates the threshold of each of the first port 11-1 of the control-target device 200-1, the second port 12-N of the control-target device 200-1, the first port 31-1 of the control-target device 200-3, the second port 32-1 of the control-target device 200-3, the first port 21-N of the control-target device 200-2, and the second port 22-1 of the control-target device 200-2, which are included in the signal path. The method of calculating the thresholds has been explained in FIG. 7 and will not be explained here.

[0083] The threshold calculation unit 310 updates the threshold calculation list with the calculated thresholds as shown in FIG. 10. FIG. 9 is a diagram showing an example of the threshold calculation list after path switching in the first embodiment. Thereafter, the threshold calculation unit 310 transmits a setting instruction including each threshold to the control-target device 200 to be set (step S208). The threshold calculation unit 310 transmits a setting instruction including a threshold of "-2 dBm" for the first port 11-1 and a threshold of "-7 dBm" for the second port 12-N to the control-target device 200-1. Furthermore, the threshold calculation unit 310 transmits a setting instruction including a threshold of "-9 dBm" for the first port 31-1 and a threshold of "-14 dBm" for the second port 32-1 to the control-target device 200-3. Furthermore, the threshold calculation unit 310 transmits a setting instruction including the threshold value "-16 dBm" for the first port 21-N and the threshold value "-21 dBm" for the second port 22-1 to the controlled device 200-2. This allows a new threshold value to be set for the controlled device 200 for which a threshold value is to be set. After the above-mentioned route switching, signal strength is monitored based on the post-switching threshold calculation list.

[0084] [Processing in Communication System 1000] Figure 11 is a sequence diagram showing the flow of processing performed by the communication system 1000 in the first embodiment. The threshold calculation unit 310 of the control device 300 executes the threshold setting processing shown in Figure 7 (step S301). As a result, the threshold calculation unit 310 transmits a threshold setting instruction to the control target device 200 for which a threshold is to be set. The threshold setting unit 210 of the control target device 200 for which a threshold is to be set receives the setting instruction transmitted from the control device 300. The threshold setting unit 210 sets a threshold for each port in accordance with the received setting instruction (step S302).

[0085] In the example shown in Fig. 7, the controlled device 200-1 obtains thresholds for the first port 11-1 and the second port 12-1. Therefore, the threshold setting unit 210 of the controlled device 200-1 sets thresholds for the first port 11-1 and the second port 12-1. Furthermore, in the example shown in Fig. 7, the controlled device 200-2 obtains thresholds for the first port 21-1 and the second port 22-1. Therefore, the threshold setting unit 210 of the controlled device 200-2 sets thresholds for the first port 21-1 and the second port 22-1.

[0086] Thereafter, the signal strength monitor 220 of each control target device 200 monitors the port (step S303). The signal strength monitor 220 transmits the monitoring result to the control device 300 (step S304). The processes of steps S303 and S304 are executed at a predetermined interval.

[0087] If an abnormality has occurred on any path based on the monitoring results obtained from each control target device 200, the analysis unit 320 of the control device 300 executes the threshold resetting process shown in Fig. 9 (step S305). This determines a new path and calculates a new threshold. The route control unit 330 instructs each control target device 200 to switch to the new path determined by the analysis unit 320. The route setting unit 230 of each control target device 200 switches the connection between ports in response to the instruction from the control device 300.

[0088] The communication system 1000 configured as described above includes a threshold calculation unit 310 that calculates a signal strength threshold to be set for at least each port of the control target device 200 based on the signal transmission strength of any one of the multiple terminal devices 100 that communicate, and instructs the control target device 200 to set the calculated signal strength threshold.

[0089] This allows the control device 300 to automatically calculate a threshold value according to the signal path between the terminal devices 100 and automatically set the calculated threshold value, thereby simplifying the threshold value setting work and reducing the time required for threshold value setting.

[0090] Furthermore, if an abnormality occurs in a section of the signal path, the control device 300 searches for a new path, automatically calculates thresholds for each port of each control-target device 200 that passes through the new path, and can automatically set the calculated thresholds. Therefore, even if an abnormality occurs in a section of the signal path, the threshold setting work can be simplified and the time required for threshold setting can be reduced.

[0091] (Variation of the First Embodiment) In the above-described embodiment, the control device 300 is configured to acquire information indicating the lower limit value of the signal transmission strength of each terminal device 100 from the higher-level device 430. The control device 300 may be configured to acquire information indicating the lower limit value of the signal transmission strength of each terminal device 100 through direct input from an operator.

[0092] (Second embodiment) In the first embodiment, a configuration was shown in which the control device automatically calculates a threshold value for each port of each control target device using the lower limit value of the signal transmission strength of the terminal device notified from the upper device, and instructs each control target device to set a threshold value. In contrast, in the second embodiment, a configuration will be described in which the control device automatically calculates a threshold value for each port of each terminal device and each control target device, and instructs each terminal device and each control target device to set a threshold value.

[0093] 12 is a diagram illustrating an example of the configuration of a communication system 1000a according to the second embodiment. In the communication system 1000a according to the second embodiment, thresholds are automatically set for ports of each terminal device 100 and each control target device 200 through which signals communicated between terminal devices pass, based on the first technique. This simplifies the threshold setting process and reduces the time required for threshold setting.

[0094] The communication system 1000a includes a plurality of terminal devices 100a-1 to 100a-2, a plurality of control target devices 200-1 to 200-3, a control device 300a, a device / line management DB 410, a topology DB 420, and a higher-level device 430. In the following explanation, an example will be described in which there are two terminal devices 100a and three control target devices 200, but the number of terminal devices 100a and control target devices 200 is not particularly limited as long as there are multiple terminal devices 100a and control target devices 200.

[0095] The communication system 1000a differs from the first embodiment in that the control device 300a newly calculates the thresholds of the ports of each terminal device 100. The following description will focus on the differences from the first embodiment.

[0096] The following explanation assumes the state shown in Fig. 12. Note that Fig. 12 shows specific numerical values ​​to clearly explain the contents of the present invention, but these numerical values ​​are merely examples. Port 1-1 of terminal device 100a-1 and port 11-1 of control target device 200-1 are connected, the distance of line a connecting port 1-1 and port 11-1 is 10 km, and the transmission loss of line a is 2 dB. Port 2-1 of terminal device 100a-2 and port 22-1 of control target device 200-2 are connected, the distance of line e connecting port 2-1 and port 22-1 is 10 km, and the transmission loss of line e is 2 dB.

[0097] Port 12-1 of control target device 200-1 and port 21-1 of control target device 200-2 are connected, the distance of line c connecting port 12-1 and port 21-1 is 20 km, and the transmission loss of line c is 4 dB. Port 12-N of control target device 200-1 and port 31-1 of control target device 200-3 are connected, the distance of line g connecting port 12-N and port 31-1 is 15 km, and the transmission loss of line g is 3 dB. Port 32-1 of control target device 200-3 and port 21-N of control target device 200-2 are connected, the distance of line i connecting port 32-1 and port 21-N is 15 km, and the transmission loss of line a is 3 dB.

[0098] As described above, in the second embodiment, the distance of some of the lines connecting the control target devices 200 is longer than in the first embodiment.

[0099] 13 is a diagram showing an example of the configuration of the terminal device 100a, the control target device 200, and the control device 300a in the second embodiment. The configurations of the terminal device 100a and the control device 300a will be described below. Note that the functions of the control target device 200 will not be described because they perform the same processing as in the first embodiment.

[0100] [Configuration of Terminal Device 100a] The terminal device 100a includes a signal strength monitoring unit 110 and a threshold setting unit 120. The terminal device 100a differs in configuration from the terminal device 100 in that it newly includes the threshold setting unit 120. The other configurations of the terminal device 100a are similar to those of the terminal device 100. The following description will focus on the differences from the terminal device 100.

[0101] The threshold setting unit 120 acquires the threshold related to the signal strength of each port notified by the control device 300a. The threshold setting unit 120 sets the acquired threshold for the corresponding port. Note that if a threshold has already been set for the port for which the threshold is to be set, the threshold setting unit 120 sets the threshold by overwriting the existing threshold with the newly acquired threshold.

[0102] [Configuration of control device 300a] The control device 300a includes a threshold calculation unit 310a, an analysis unit 320, and a route control unit 330. The control device 300a differs in configuration from the control device 300 in that the control device 300a includes a threshold calculation unit 310a instead of the threshold calculation unit 310. The other configurations of the control device 300a are similar to those of the control device 300. The following description will focus on the differences from the control device 300.

[0103] The threshold calculation unit 310a calculates the signal strength thresholds for each port of each terminal device 100a and for each port of each control-target device 200 through which signals communicated between the terminal device 100a-1 and the terminal device 100a-2 pass, based on the device / line management list provided by the device / line management DB 410, the connection relationship list provided by the topology DB 420, and the lower limit value of the signal transmission strength of the terminal device 100a notified by the higher-level device 430. The threshold calculation unit 310a notifies each terminal device 100a of the calculated signal strength thresholds for each port of each terminal device 100a via interface B. The threshold calculation unit 310a notifies each control-target device 200 of the calculated signal strength thresholds for each port of each control-target device 200 via interface A.

[0104] As described above, the threshold calculation unit 310a calculates the signal strength threshold of each port of each control target device 200 through which the signal communicated between the terminal device 100a-1 and the terminal device 100a-2 passes. Therefore, there may be some control target devices 200 for which the signal strength threshold of a port cannot be calculated, depending on the route the signal passes through.

[0105] [Details of the Equipment and Line Management List] Figure 14 is a diagram showing an example of the equipment and line management list in the second embodiment. The equipment and line management list has multiple records representing information about each line that constitutes the signal path connecting the terminal device 100a-1 and the terminal device 100a-2. Each record has an item number, line, section (start point), section (end point), and loss value. Note that the item number, line, section (start point), section (end point), and loss have been explained in the first embodiment, so they will not be explained here. In the example shown in Figure 14, the loss values ​​in item numbers "7" and "9" are different, and are the same as those in the first embodiment.

[0106] [Details of the Connection Relationship List] Figure 15 is a diagram showing an example of a connection relationship list in the second embodiment. The connection relationship list has multiple records representing information about the connection relationship for each signal path connecting the terminal device 100a-1 and the terminal device 100a-2. Depending on the connection relationship, there may be multiple signal paths connecting the terminal device 100a-1 and the terminal device 100a-2. Therefore, the connection relationship list registers the connection relationships for each of all possible signal paths. Each record has values ​​for an item number, an endpoint A, a line or a controlled device, and an endpoint B. Note that the item number, endpoint A, a line or a controlled device, and endpoint B have been explained in the first embodiment and will not be explained here.

[0107] [Threshold Setting Process] Next, the threshold setting process performed by the control device 300a in the second embodiment will be described. Note that the threshold setting process performed by the control device 300a in the second embodiment will be described taking as an example a case where the signal path is configured with the connection relationship registered in item number "1" in the connection relationship list shown in Fig. 15. That is, assume that the initial connection state is a state in which the terminal device 100a-1 and the terminal device 100a-2 are connected by a signal line (for example, line a ⇒ line b ⇒ line c ⇒ line d ⇒ line e) that passes through the control target devices 300-1 and 300-2, as shown in Fig. 12.

[0108] The threshold calculation unit 310a acquires information about the lower limit value (e.g., 0 dBm) of the signal transmission strength of the terminal device 100a-1 notified by the higher-level device 430 via interface X. Note that the terminal device 100a-1 and the terminal device 100a-2 have the same lower limit value of the signal transmission strength. Therefore, the threshold calculation unit 310a may acquire information about the lower limit value of the signal transmission strength from the terminal device 100a-2.

[0109] Furthermore, at least the terminal device 100a-1 or 100a-2 (including both the terminal device 100a-1 and 100a-2) may notify the control device 300a of information on the lower limit of the signal transmission strength of the own device. Furthermore, the control device 300a may request at least the terminal device 100a-1 or 100a-2 (including both the terminal device 100a-1 and 100a-2) to notify the lower limit of the signal transmission strength.

[0110] The threshold calculation unit 310a requests the topology DB 420 to provide a connection relationship list relating to signal paths connecting the terminal devices 100a via interface G. In response, the threshold calculation unit 310a obtains the connection relationship list from the topology DB 420 via interface H. Note that the connection relationship list obtained by the threshold calculation unit 310a here is a record corresponding to item number "1," which is the state at the time of initial connection.

[0111] Next, in order to check the loss of each line and the control target device 200 described in the record corresponding to item number "1" in the acquired connection relationship list, the threshold calculation unit 310a requests the device / line management DB 410 to provide the device / line management list via interface I. For example, the threshold calculation unit 310a may request the provision of the device / line management list by transmitting to the device / line management DB 410 "line a, control target device 200-1 (11-1), line b, control target device 200-1 (12-1), line c, control target device 200-2 (21-1), line d, control target device 200-2 (22-1), line e" described in the line or control target device item of the record corresponding to item number "1".

[0112] As a result, the threshold calculation unit 310a acquires an equipment / line management list from the equipment / line management DB 410 via the interface J. Note that the equipment / line management list acquired by the threshold calculation unit 310a here is the record corresponding to item numbers "1" to "5". As a result, the threshold calculation unit 310a acquires information on the transmission loss of line a of "2 dB", the loss of line b (equivalent to the insertion loss of the control target device 200-1) of "5 dB", the transmission loss of line c of "4 dB", the loss of line d (equivalent to the insertion loss of the control target device 200-2) of "5 dB", and the transmission loss of line e of "2 dB".

[0113] Based on the acquired information, the threshold calculation unit 310a calculates the threshold of each port of each terminal device 100a and the threshold of each port of each control target device 200. For example, the threshold calculation unit 310a calculates the threshold of each of the following ports included in the signal path: port 1-1 of the terminal device 100a-1, the first port 11-1 of the control target device 200-1, the second port 12-1 of the control target device 200-1, the first port 21-1 of the control target device 200-2, the second port 22-1 of the control target device 200-2, and port 2-1 of the terminal device 100a-2. Since the calculation of the threshold for the control target device 200 has been explained in the first embodiment, the calculation of the threshold for the terminal device 100a will be explained as an example.

[0114] (Method of calculating the threshold for port 1-1 of terminal device 100a-1) The lower limit of the signal transmission strength of the terminal device 100a-1 is "0 dBm." Therefore, the threshold calculation unit 310a calculates 0 dBm as the threshold for port 1-1 of the terminal device 100a-1. In this way, the threshold calculation unit 310a calculates the threshold by using the lower limit of the signal transmission strength of the terminal device 100-1 as a reference and subtracting the loss that occurs from the terminal device 100a-1 to the port for which the threshold is calculated.

[0115] (Method of Calculating the Threshold of Port 2-1 of Terminal Device 100a-2) The threshold calculation unit 310a subtracts the loss (transmission loss) of line a of 2 dB, the loss of line b of 5 dB (corresponding to the insertion loss of the controlled device 200-1), the loss (transmission loss) of line c of 4 dB, the loss of line d of 5 dB (corresponding to the insertion loss of the controlled device 200-1), and the loss (transmission loss) of line e of 2 dB from the lower limit of the signal transmission strength of the terminal device 100a-1 of 0 dBm. As a result, the threshold calculation unit 310a calculates 0-2-5-4-5-2 = -18 dBm as the threshold of port 2-1 of the terminal device 100a-2.

[0116] The threshold calculation unit 310a saves each calculated threshold as a threshold calculation list as shown in FIG. 16. FIG. 16 is a diagram showing an example of a threshold calculation list in the second embodiment. The threshold calculation list has multiple records that represent information about the threshold of each port calculated by the threshold calculation unit 310a. Each record has an item number, a port, and a threshold value. The item number represents an identification number for identifying the record number. The port represents the port for which the threshold was calculated. The threshold represents the threshold calculated by the threshold calculation unit 310a.

[0117] Thereafter, the threshold calculation unit 310a transmits setting instructions including each threshold to the terminal device 100a and the controlled device 200 that are to be set. The threshold calculation unit 310a transmits a setting instruction including a threshold of "0 dBm" for port 1-1 to the terminal device 100a-1 via interface B. The threshold calculation unit 310a transmits a setting instruction including a threshold of "-2 dBm" for the first port 11-1 and a threshold of "-7 dBm" for the second port 12-1 to the controlled device 200-1 via interface A. Furthermore, the threshold calculation unit 310a transmits a setting instruction including a threshold of "-11 dBm" for the first port 21-1 and a threshold of "-16 dBm" for the second port 22-1 to the controlled device 200-2 via interface A. Furthermore, the threshold calculation unit 310a transmits a setting instruction including the threshold value of "-18 dBm" for port 2-1 to the terminal device 100a-2 via interface B. This makes it possible to set threshold values ​​for the terminal device 100a and the controlled device 200 for which threshold values ​​are to be set.

[0118] For example, the threshold setting unit 120 of the terminal device 100a-1 receives a setting instruction transmitted from the control device 300a. The threshold setting unit 120 sets the threshold "0 dBm" included in the received setting instruction to port 1-1. For example, the threshold setting unit 120 of the terminal device 100a-2 receives a setting instruction transmitted from the control device 300a. The threshold setting unit 120 sets the threshold "-18 dBm" included in the received setting instruction to port 2-1.

[0119] [Threshold Reset Processing] Next, the flow of the threshold reset processing performed by the control device 300a in the second embodiment will be described. Note that this processing is executed after the above-mentioned threshold setting processing has been performed. Therefore, the connection state at the start of this processing is a state in which the terminal device 100a-1 and the terminal device 100a-2 are connected by a signal line that passes through the control target devices 300-1 and 300-2.

[0120] The analysis unit 320 periodically acquires monitoring results from each terminal device 100a and each control target device 200. The analysis unit 320 determines whether or not an abnormality has occurred based on the acquired monitoring results of each terminal device 100a and each control target device 200. If the analysis unit 320 determines that no abnormality has occurred, the control device 300a ends the threshold resetting process.

[0121] On the other hand, if the analysis unit 320 determines that an abnormality has occurred, the analysis unit 320 determines a new signal path. Here, for example, a case will be described in which, for the first port 21-1 (for example, item 3 in FIG. 16 ) of the control target device 200-2, for which the threshold value is set to "-11 dBm," normal communication status has been reported up until that point, but at a certain point in time, an abnormality has occurred and a signal strength of "-35 dBm" that is significantly below the threshold is reported, resulting in a disconnection of communication between the terminal devices 100a.

[0122] The analysis unit 320 has been notified by each terminal device 100a and each control target device 200 that the communication status for ports other than the first port 21-1 is normal, and therefore determines that some kind of failure (such as a break in the signal line) has occurred between the second port 12-1 of the control target device 200-1 and the first port 21-1 of the control target device 200-2 (line c). If this continues, the communication interruption will continue, so the analysis unit 320 searches for a signal path that can bypass the faulty location (line c).

[0123] Then, it is assumed that the analysis unit 320 finds a new signal path that passes through the control-target device 200-3 (item number N in FIG. 15 ). In this case, the analysis unit 320 decides to switch to the new signal path. The analysis unit 320 instructs the path control unit 330 to switch to the determined new signal path via interface E. In response to the instruction from the analysis unit 320, the path control unit 330 instructs the corresponding control-target device 200 to switch paths via interface F.

[0124] Specifically, the route control unit 330 instructs the control target device 200-1 to switch the connection port of the first port 11-1 from the second port 12-1 to 12-N. The route control unit 330 also instructs the control target device 200-3 to set the connection port of the first port 31-1 to the second port 32-1. Furthermore, the route control unit 330 instructs the control target device 200-2 to switch the connection port of the first port 22-1 from the second port 21-1 to 21-N. Once these route settings are complete, the communication service between the terminal devices 100 can be restored using a new signal path that bypasses the line c where the failure occurred.

[0125] Note that even after the above-mentioned path switching, the control device 300a needs to automatically reset the threshold list in order to monitor the signals at each port. Therefore, in response to the path switching by the path control unit 330, the threshold calculation unit 310a requests the topology DB 420 to provide a connection relationship list related to the signal paths connecting the terminal devices 100a via interface G. In response to this, the threshold calculation unit 310a obtains the connection relationship list from the topology DB 420 via interface H. Note that the connection relationship list obtained by the threshold calculation unit 310a here is the record corresponding to item number "N," which is the state after the path switching.

[0126] Next, in order to check the losses of each line and the controlled device 200 described in the record corresponding to item number "N" in the acquired connection relationship list, the threshold calculation unit 310a requests the equipment / line management DB 410 to provide the equipment / line management list via interface I. For example, the threshold calculation unit 310a may request the equipment / line management list by sending information described in the line or controlled device item of the record corresponding to item number "N" to the equipment / line management DB 410.

[0127] As a result, the threshold calculation unit 310a acquires an equipment / line management list from the equipment / line management DB 410 via the interface J. Note that the equipment / line management list acquired by the threshold calculation unit 310a here is the record corresponding to item numbers "1", "5", and "6" to "10". As a result, the threshold calculation unit 310a acquires information on the transmission loss of line a of "2 dB", the loss of line f (equivalent to the insertion loss of the controlled device 200-1) of "5 dB", the transmission loss of line g of "2 dB", the loss of line h (equivalent to the insertion loss of the controlled device 200-3) of "5 dB", the transmission loss of line i of "2 dB", the loss of line j (equivalent to the insertion loss of the controlled device 200-2) of "5 dB", and the transmission loss of line e of "2 dB".

[0128] Based on the acquired information, the threshold calculation unit 310a calculates the threshold of each port of each terminal device 100a and each control target device 200. For example, the threshold calculation unit 310a calculates the threshold of each of the following ports included in the signal path: port 1-1 of the terminal device 100a-1, the first port 11-1 of the control target device 200-1, the second port 12-N of the control target device 200-1, the first port 31-1 of the control target device 200-3, the second port 32-1 of the control target device 200-3, the first port 21-N of the control target device 200-2, the second port 22-1 of the control target device 200-2, and port 2-1 of the terminal device 100a-2. The method of calculating the threshold has been explained in FIG. 7 and will not be explained here.

[0129] The threshold calculation unit 310a updates the threshold calculation list with the calculated thresholds as shown in Fig. 17. Fig. 17 is a diagram showing an example of the threshold calculation list after route switching in the second embodiment. Thereafter, the threshold calculation unit 310a transmits a setting instruction including each threshold to the terminal device 100a and the control target device 200 that are the setting targets. This makes it possible to set new thresholds for the terminal device 100a and the control target device 200 that are the threshold setting targets. After the route switching, signal strength is monitored based on the threshold calculation list after switching.

[0130] According to the communication system 1000a of the second embodiment configured as above, it is possible to obtain the same effects as those of the first embodiment.

[0131] Furthermore, in the communication system 1000a, it is possible to set a signal strength threshold not only for the control target device 200 but also for the ports of the terminal device 100a. This allows the terminal device 100a to set an appropriate threshold according to the signal path. This makes it possible to improve convenience.

[0132] (Variation of the Second Embodiment) In the above-described embodiment, the control device 300a is configured to acquire information indicating the lower limit value of the signal transmission strength of each terminal device 100a from the higher-level device 430. The control device 300a may be configured to acquire information indicating the lower limit value of the signal transmission strength of each terminal device 100a through direct input from an operator.

[0133] (Third embodiment) In the first embodiment, a configuration was shown in which the control device automatically calculates the threshold value of each port of each control target device using the lower limit value of the signal transmission strength of the terminal device notified by the upper device. In the second embodiment, a configuration was shown in which the control device automatically calculates the threshold value of each port of each terminal device and each control target device using the lower limit value of the signal transmission strength of the terminal device notified by the upper device.

[0134] In contrast, in the third embodiment, a configuration is described in which the control device automatically calculates the threshold value of each port of each controlled device using an arbitrary value for calculating the threshold value notified from the higher-level device, and instructs each controlled device to set the threshold value.

[0135] The system configuration of the communication system 1000 in the third embodiment and the configuration of each device (e.g., terminal device 100, control target device 200, and control device 300) are the same as those in the first embodiment. The following description focuses on the differences from the first embodiment. Note that the communication system 1000 in the third embodiment automatically sets thresholds for ports of each control target device 200 through which signals communicated between terminal devices pass, based on the second technique. This simplifies the threshold setting process and reduces the time required for threshold setting.

[0136] In the third embodiment, information indicating the signal strength of each port of each control target device 200 when the terminal devices 100 are initially connected is newly registered in the device / line management list stored in the device / line management DB 410. A specific configuration will be described later.

[0137] The control device 300 in the third embodiment calculates the signal strength threshold of each port of each control-target device 200 based on information indicating an arbitrary value (hereinafter referred to as a "margin value") for calculating the threshold notified from the higher-level device 430, the device / line management list stored in the device / line management DB 410, and the connection relationship list stored in the topology DB 420. For example, the control device 300 automatically calculates the threshold of each port of each control-target device 200 by subtracting the margin value from the signal strength in the initial connection state as the threshold of each port in the connection relationship list. Here, the margin value is described as being the same for each port, but it may be a different value for each port.

[0138] Furthermore, the control device 300 performs route control for each control-target device 200 as necessary. For example, if an abnormality occurs in a section of a signal path, the control device 300 performs route control for the control-target device 200 related to the section where the abnormality occurred. The control device 300 changes the transfer route of communication data between the terminal devices 100 by controlling the route settings of one or more control-target devices 200. This allows the control device 300 to continue communication. Note that, although a configuration in which one control device 300 controls multiple control-target devices 200 is shown here, a control device 300 may be provided for each control-target device 200.

[0139] The upper device 430 provides the control device 300 with margin values ​​for each port provided in each of the terminal device 100 and the control target device 200 .

[0140] [Details of the Equipment and Line Management List] Figure 18 is a diagram showing an example of the equipment and line management list in the third embodiment. The equipment and line management list has multiple records representing information about each line that constitutes the signal path connecting the terminal device 100-1 and the terminal device 100-2. Each record has an item number, line, section (start point), section (end point), and loss value. Here, in the equipment and line management list in the third embodiment, a port and each value of signal strength are registered for each section (start point) and section (end point).

[0141] The port in the section (starting point) represents the port that is the starting point of the line. The signal strength in the section (starting point) represents the signal strength of the port that is the starting point of the line at the time of initial connection between the terminal devices 100-1 and 100-2. The port in the section (ending point) represents the port that is the ending point of the line. The signal strength in the section (ending point) represents the signal strength of the port that is the ending point of the line at the time of initial connection between the terminal devices 100-1 and 100-2.

[0142] 18, item number "1" has registered therein information indicating "a" as the line, information indicating "1-1" as the port of the section (starting point), information indicating "-2" as the signal strength of the section (starting point), information indicating "11-1" as the port of the section (ending point), information indicating "-4" as the signal strength of the section (ending point), and information indicating "2" as the loss. That is, item number "1" indicates that a part of the section of the signal path connecting the terminal device 100-1 and the terminal device 100-2 is the line "a", the line "a" is the path connecting the port "1-1" and the port "11-1", the signal strength of the port "1-1" at the time of initial connection is "-2", the signal strength of the port "11-1" at the time of initial connection is "-4", and a signal loss of "2 dB" occurs.

[0143] As described above, the equipment and line management list registers information about each of the sections of the signal path connecting the terminal unit 100-1 and the terminal unit 100-2.

[0144] [Threshold Setting Process] Fig. 19 is a flowchart showing the flow of the threshold setting process performed by the control device 300 in the third embodiment. Note that the process in Fig. 19 will be described taking as an example a case where the signal path is configured with the connection relationship registered at item number "1" in the connection relationship list. That is, the initial connection state in the process in Fig. 19 is assumed to be a state in which the terminal device 100a-1 and the terminal device 100a-2 are connected by a signal line (for example, line a ⇒ line b ⇒ line c ⇒ line d ⇒ line e) that passes through the control target devices 300-1 and 300-2, as shown in Fig. 12.

[0145] The threshold calculation unit 310 acquires a margin value notified by the higher-level device 430 via interface X (step S401). Here, as an example, the threshold calculation unit 310 acquires a margin value of "2 dB." The threshold calculation unit 310 requests the topology DB 420 to provide a connection relationship list regarding signal paths connecting the terminal devices 100 via interface G. In response, the threshold calculation unit 310 acquires the connection relationship list from the topology DB 420 via interface H (step S402). Note that the connection relationship list acquired by the threshold calculation unit 310 here is a record corresponding to item number "1," which is the state at the time of initial connection.

[0146] Next, in order to check the loss of each line and the control target device 200 described in the record corresponding to item number "1" in the acquired connection relationship list, the threshold calculation unit 310 requests the device / line management DB 410 to provide the device / line management list via interface I. For example, the threshold calculation unit 310 may request the provision of the device / line management list by transmitting to the device / line management DB 410 "line a, control target device 200-1 (11-1), line b, control target device 200-1 (12-1), line c, control target device 200-2 (21-1), line d, control target device 200-2 (22-1), line e" described in the line or control target device item of the record corresponding to item number "1".

[0147] As a result, the threshold calculation unit 310 acquires an equipment / line management list from the equipment / line management DB 410 via the interface J (step S403). Note that the equipment / line management list acquired by the threshold calculation unit 310 here is the record corresponding to item numbers "1" to "5". As a result, the threshold calculation unit 310 acquires information on the transmission loss of line a of "2 dB", the loss of line b (equivalent to the insertion loss of the controlled device 200-1) of "5 dB", the transmission loss of line c of "4 dB", the loss of line d (equivalent to the insertion loss of the controlled device 200-2) of "5 dB", and the transmission loss of line e of "2 dB".

[0148] The threshold calculation unit 310 calculates the threshold of each port of each control-target device 200 based on the acquired information (step S404). The threshold calculation unit 310 calculates the threshold of each of the first port 11-1 of the control-target device 200-1, the second port 12-1 of the control-target device 200-1, the first port 21-1 of the control-target device 200-2, and the second port 22-1 of the control-target device 200-2, which are included in the signal path. The method of calculating the threshold will be described below.

[0149] (Method of calculating threshold for first port 11-1 of controlled device 200-1) As shown in FIG. 18 , the signal strength in the initial connection state of the first port 11-1 of the controlled device 200-1 is "-4 dBm." Therefore, the threshold calculation unit 310 subtracts a margin value of "2 dB" from the signal strength in the initial connection state of the first port 11-1 of "-4 dBm." As a result, the threshold calculation unit 310 calculates -4 - 2 = -6 dBm as the threshold for the first port 11-1 of the controlled device 200-1. In this way, the threshold calculation unit 310 calculates the threshold by subtracting the loss that occurs from the terminal device 100-1 to the port that is the target of threshold calculation, using the value of the signal transmission strength at the time of initial connection between the terminal devices 100 as a reference.

[0150] 18, the signal strength of the second port 12-1 of the control target device 200-1 in the initial connection state is "-9 dBm." Therefore, the threshold calculation unit 310 subtracts a margin value of "2 dB" from the signal strength of the second port 12-1 in the initial connection state of "-9 dBm." As a result, the threshold calculation unit 310 calculates -9 - 2 = -11 dBm as the threshold for the second port 12-1 of the control target device 200-1.

[0151] 18, the signal strength of the first port 21-1 of the control target device 200-2 in the initial connection state is "-13 dBm." Therefore, the threshold calculation unit 310 subtracts a margin value of "2 dB" from the signal strength of the first port 21-1 in the initial connection state of "-13 dBm." As a result, the threshold calculation unit 310 calculates -13-2 = -15 dBm as the threshold for the first port 21-1 of the control target device 200-2.

[0152] 18, the signal strength of the second port 22-1 of the control target device 200-1 in the initial connection state is "-18 dBm." Therefore, the threshold calculation unit 310 subtracts a margin value of "2 dB" from the signal strength of the second port 22-1 in the initial connection state of "-18 dBm." As a result, the threshold calculation unit 310 calculates -18-2 = -20 dBm as the threshold for the second port 22-1 of the control target device 200-2.

[0153] The threshold calculation unit 310 saves the calculated thresholds as a threshold calculation list as shown in FIG. 20 . FIG. 20 is a diagram showing an example of a threshold calculation list in the third embodiment. Thereafter, the threshold calculation unit 310 transmits a setting instruction including each threshold to the controlled device 200 to be set (step S405). The threshold calculation unit 310 transmits a setting instruction including a threshold of "-6 dBm" for the first port 11-1 and a threshold of "-11 dBm" for the second port 12-1 to the controlled device 200-1 via interface A. Furthermore, the threshold calculation unit 310 transmits a setting instruction including a threshold of "-15 dBm" for the first port 21-1 and a threshold of "-20 dBm" for the second port 22-1 to the controlled device 200-2 via interface A. This makes it possible to set thresholds for the controlled device 200 to be set.

[0154] [Threshold Reset Processing] The flow of the threshold reset processing in the third embodiment is the same as that in the first embodiment, except for the difference in the threshold calculation method. The threshold calculation method in the threshold reset processing in the third embodiment is the same as the method described in FIG. 19. The threshold calculation unit 310 saves each threshold calculated by the threshold reset processing as a threshold calculation list as shown in FIG. 21. FIG. 20 is a diagram showing an example of the threshold calculation list after route switching in the third embodiment.

[0155] According to the communication system 1000 of the third embodiment configured as described above, the system is provided with a threshold calculation unit 310 that calculates a signal strength threshold to be set for at least each port of the control target device 200 based on information indicating the signal strength of each port of one or more control target devices through which signals transmitted and received between the multiple terminal devices 100 pass at the time of initial connection of the multiple terminal devices 100, and instructs the control target device 200 to set the calculated signal strength threshold.

[0156] This allows the control device 300 to automatically calculate a threshold value according to the signal path between the terminal devices 100 and automatically set the calculated threshold value, thereby simplifying the threshold value setting work and reducing the time required for threshold value setting.

[0157] Furthermore, if an abnormality occurs in a section of the signal path, the control device 300 searches for a new path, automatically calculates thresholds for each port of each control-target device 200 that passes through the new path, and can automatically set the calculated thresholds. Therefore, even if an abnormality occurs in a section of the signal path, the threshold setting work can be simplified and the time required for threshold setting can be reduced.

[0158] (Variation of the Third Embodiment) In the above-described embodiment, the control device 300 is configured to acquire information indicating a margin value from the higher-level device 430. The control device 300 may be configured to acquire information indicating a margin value through direct input from an operator.

[0159] (Variant example common to the first to third embodiments) In each of the above-described embodiments, the controlled device 200 has been described as an example of a device having a function of setting routes, but the controlled device 200 may also be a device having a signal amplification function or a signal regeneration function.

[0160] The terminal devices 100, 100a, the control target device 200, and the control devices 300, 300a in the above-described embodiments may be partially or entirely implemented by a computer. In this case, a program for implementing the functions may be recorded on a computer-readable recording medium, and the program may be read into and executed by a computer system. Note that the term "computer system" as used herein includes hardware such as an operating system (OS) and peripheral devices.

[0161] Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs (Read Only Memory), and CD-ROMs, as well as storage devices such as hard disks built into computer systems. Furthermore, the term "computer-readable recording medium" may also include devices that dynamically store programs for a short period of time, such as communication lines used when transmitting programs over networks like the Internet or communication lines like telephone lines, and devices that store programs for a fixed period of time, such as volatile memory within the computer systems that serve as servers or clients in such cases. The above programs may also be recorded on computer-readable recording media. Examples of computer-readable recording media include portable media such as flexible disks, magneto-optical disks, ROMs, CD-ROMs, and semiconductor storage devices (e.g., solid-state drives (SSDs)), as well as storage devices such as hard disks and semiconductor storage devices built into computer systems. The above programs may also be transmitted via telecommunications lines.

[0162] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0163] The present invention can be applied to a technique for monitoring communications between terminal devices.

[0164] DESCRIPTION OF SYMBOLS 100, 100a... Terminal device, 110... Signal strength monitoring unit, 120... Threshold setting unit, 200... Control target device, 210... Threshold setting unit, 220... Signal strength monitoring unit, 230... Route setting unit, 300, 300a... Control device, 310, 310a... Threshold calculation unit, 320... Analysis unit, 330... Route control unit, 410... Device / line management DB, 420... Topology DB, 430... Upper device

Claims

a threshold calculation unit that calculates a signal strength threshold to be set for each port of at least one of the one or more control target devices based on information indicating a lower limit value of a signal transmission strength of any of a plurality of terminal devices that communicate, or information indicating the signal strength of each port of one or more control target devices through which signals transmitted and received between the plurality of terminal devices pass at the time of initial connection of the plurality of terminal devices, and instructs the one or more control target devices to set the calculated signal strength threshold; A control device comprising: 　 the threshold calculation unit calculates the signal strength threshold for each port by subtracting a loss occurring from a terminal device that is a signal transmission target to a port that is a target for calculating the threshold, using a lower limit value specified by the information indicating the lower limit value of the signal transmission strength as a reference; The control device according to claim 1 . 　 the threshold calculation unit calculates a signal strength threshold to be set for each port of the one or more control target devices and each port of each of the plurality of terminal devices based on information indicating a lower limit value of the signal transmission strength, and instructs the one or more control target devices and the plurality of terminal devices to set the calculated signal strength thresholds; The control device according to claim 1 . 　 the threshold calculation unit calculates the signal strength threshold for each port by subtracting a value specified by the information indicating the signal strength at each port that is the target of threshold calculation from a terminal device that is the target of signal transmission, using an arbitrary value for calculating the threshold for each port as a reference; The control device according to claim 1 . 　 further comprising an analysis unit that searches for a new path when an abnormality occurs in a section of a signal path connecting the plurality of terminal devices; the threshold calculation unit recalculates the signal strength threshold for each port on the new route; The control device according to any one of claims 1 to 4. 　 Acquire information indicating a lower limit value of the signal transmission strength of one of a plurality of terminal devices that communicate, or information indicating the signal strength of each port of one or more control target devices through which signals transmitted and received between the plurality of terminal devices pass at the time of initial connection of the plurality of terminal devices, calculating a signal strength threshold to be set for each port of at least the one or more control target devices based on the acquired information indicating the lower limit value of the signal transmission strength or the information indicating the signal strength; A control method for instructing the one or more control target devices to set the calculated threshold value of the signal strength.

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