Distributed system and method for creating communication path in distributed system

Abstract

To make it possible to create communication paths in a distributed system with a simpler configuration.SOLUTION: In order to solve the above problem, the present invention is, in distributed systems each consisting of a plurality of distributed devices such as a communication master station and a plurality of communication slave stations, a distributed system that dynamically updates a communication port with the upstream side according to an amount of passage of a communication path through which routing packets are communicated, creates a communication route based on this, and, if a communication failure has occurred in the distributed system, creates a detour route to bypass the communication failure as a communication route.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a technique for generating a communication path that bypasses a failure such as a failure occurring in a network. Note that the failure of the present invention includes various abnormalities in communication such as failures.

Background Art

[0002] Currently, various communication technologies using a network are being used. As an application example of this communication technology, industrial devices can be cited. In industrial devices such as biochemical and immunoassay devices, it is common to use an electronic system having an analog transmission path from a plurality of centrally managed control boards to control devices such as sensors and motors mounted on the device.

[0003] In recent years, for the purpose of improving the efficiency of device design, manufacturing, and maintenance, a distributed control system has been applied to reduce the amount of analog transmission paths and improve the control performance of the device by modularizing and dispersing the control boards. In a distributed system including such a distributed control system, in order to reduce the downtime of the devices (distributed control devices, distributed devices) constituting the system, a redundant network having a plurality of communication paths may be used so that control communication can be continued even when a part of the device fails. In such a redundant network, it is possible to take a plurality of communication paths between the boards connected to the network. Therefore, if an appropriate communication path is not generated, it may cause malfunction. In addition, when a problem such as a failure occurs, it is necessary to generate a bypass path that can bypass the failure location and continue communication by using the remaining redundant paths, and to identify the failure location for prompt repair.

[0004] As a means to solve these problems, when a failure occurs in a redundant network, a communication master station generates a detour route from network configuration information and scans whether it is possible to communicate with each communication slave station via the detour route to identify the failure location. Such a technique is generally known, and for example, Patent Document 1 has been proposed. In Patent Document 1, among the communication routes from the aggregation device to the terminal device that has become incommunicable when a communication failure occurs, the relay device closest to the terminal device side that is communicable is specified as the target device, and the aggregation device generates a detour route from the network configuration information to the target device, and identifies the section between the relay device closest to the target device side that can communicate via the detour route as the failure location.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the technique described in Patent Document 1, the relay device is a device having a routing function such as a so-called router, and in a general routing function protocol, the relay device needs to store route information to other relay devices. Therefore, it is difficult to ensure the real-time performance of control communication due to the compression of the communication bandwidth, and the relay device must be provided with a storage capacity corresponding to the scale of the distributed system such as a distributed control system. Therefore, an object of the present invention is to realize the creation of a communication route in a distributed system with a simpler configuration.

Means for Solving the Problems

[0007] In order to solve the above problems, in the present invention, in a distributed system composed of a plurality of distributed devices such as a communication master station and a plurality of communication slave stations, the communication port with the upstream side is dynamically updated according to the throughput of the communication route through which the routing packet is communicated, and based on this, a communication route is created.

[0008] An example of a more specific configuration is a distributed system composed of a communication master station and a plurality of communication slave stations connected in the downstream direction of communication with respect to the communication master station. Each of the communication master station and the plurality of communication slave stations is connected to each other via a communication path. Each of the plurality of communication slave stations has a plurality of communication ports for communication, stores any one of the plurality of communication ports as an upstream port for communicating in the upstream direction, transmits a routing packet from the communication master station to each of the plurality of communication slave stations, and in each of the plurality of communication slave stations, identifies a first throughput indicating the throughput of the routing packet from the communication master station, and compares the first throughput with a second throughput identified before the identification the second throughput last received by each of the plurality of communication slave stations with the smallest throughput to determine whether the first throughput is small and in each of the plurality of communication slave stations, identifies a first communication port that has received the routing packet, and in each of the plurality of communication slave stations, the first throughput is small if so, updates the first communication port as the upstream port. in each of the plurality of communication slave stations, the first throughput is increased and transferred for the routing packet from a communication port provided by the communication slave station itself other than the received communication port The communication master station is a distributed system that creates a communication path from the communication master station in the distributed system by combining each upstream port in the plurality of communication slave stations and the communication path connected to the upstream port. The present invention also includes a method for creating a communication path in this distributed system.

Advantages of the Invention

[0009] According to the present invention, in the present invention, it is possible to realize the creation of a communication path in a distributed system with a simpler configuration. In addition, problems, configurations, and effects other than the above are clarified by the following embodiments and the description of each example.

Brief Description of the Drawings

[0010]

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Mode for Carrying Out the Invention

[0011] Hereinafter, an embodiment of the present invention will be described. In this embodiment, as an example of a distributed system, a distributed control system for controlling a control target including itself will be taken as an example. FIG. 1 is a diagram showing a configuration example of the distributed control system 01 in this embodiment. In FIG. 1, the distributed control system 01 includes a communication master station 011 and a plurality of communication slave stations 012. Here, the communication master station 011 and the communication slave stations 012 correspond to the distributed devices of the present invention. Also, the direction of communication facing upward on the drawing, that is, the direction of communication toward the communication master station 011, is defined as the upstream direction. Also, the opposite direction is defined as the downstream direction.

[0012] In this embodiment, in the distributed control system 01 composed of the communication master station 011 and a plurality of communication slave stations 012, the upstream port, which is the communication port with the upstream side, is dynamically updated according to the throughput of the communication path through which the routing packet is communicated. Then, based on this, a communication path is created. An example of a more specific configuration is in the distributed control system 01 composed of the communication master station 011 and a plurality of communication slave stations 012 connected to the communication master station 011 in the downstream direction of communication. Each of the communication master station 011 and the plurality of communication slave stations 012 is connected to each other via a communication path (such as the normal communication path 0130 and the degenerate communication path 0131). Each of the plurality of communication slave stations 012 has a plurality of communication ports 0120 for communication, stores any one of the plurality of communication ports 0120 as the upstream port, transmits a routing packet from the communication master station 011 to each of the plurality of communication slave stations 012, and in each of the plurality of communication slave stations 012, identifies a first throughput indicating the throughput of the routing packet from the communication master station 011, compares the first throughput with a second throughput identified before the identification, determines whether a predetermined condition is satisfied, in each of the plurality of communication slave stations 012, identifies the first communication port that has received the routing packet, and in each of the plurality of communication slave stations 012, when the predetermined condition is satisfied, updates the first communication port as the upstream port. The communication master station 011 combines each upstream port in the plurality of communication slave stations 012 and the communication path connected to the upstream port to create a communication path from the communication master station 011 in the distributed control system 01, which is the distributed control system 01.

[0013] The description of this embodiment ends here. Next, each example showing a more specific configuration and processing content will be described.

Example

[0014] As shown in FIG. 1, the distributed control system 01 in this embodiment includes a communication master station 011 and a plurality of communication slave stations 012. The communication master station 011 forms a network connected to the plurality of communication slave stations 012 via communication paths (such as a normal communication path 0130 and a degenerate communication path 0131), and transmits control commands of the distributed control system 01 to the communication slave stations. The communication slave station 012 is connected to the communication master station 011 and other communication slave stations 012 through the network, and transmits input information from the control device to the communication master station 011.

[0015] Next, the configuration of each device will be described. The communication slave station 012 includes a plurality of communication ports 0120. Among these, the communication port 0120 used for transmitting its own input information and transferring input information from the control devices of other communication slave stations 012 is defined as an upstream port. Also, the communication port 0120 used for transferring control commands from the communication master station 011 to other communication slave stations 012 is defined as a downstream port.

[0016] In addition, the communication master station 011 includes a communication port 0110, an upstream port storage unit 0111, a communication path storage unit 0112, a fault location identification unit 0113, and a communication path creation unit 0114. The upstream port storage unit 0111 stores the upstream ports of the communication slave stations 012 themselves. The communication path storage unit 0112 stores the created communication paths. The fault location identification unit 0113 identifies the fault location. The communication path creation unit 0114 creates a communication path according to the passing amount of routing packets.

[0017] Furthermore, the distributed control system 01 has a normal communication path 0130 and a degraded communication path 0131. The normal communication path 0130 connects between the communication port 0110 and the communication port 0120, or between the communication ports 0120, such that the communication path used by each communication sub-station 012 and the communication master station 011 during normal times has the minimum number of routing times through the smallest communication sub-station 012. The degraded communication path 0131 connects between the communication ports 0120. In this connection, for each communication sub-station 012, the communication path used for communication with the communication master station 011 when any one of the other communication sub-stations 012 or the normal communication path 0130 fails is configured by a combination of communication paths with a number of routing times through the communication sub-station 012 that allows communication within a predetermined communication delay time.

[0018] Next, a method for generating a communication path in the distributed control system 01 will be described. First, the communication path creation unit 0114 of the communication master station 011 transmits the routing packet 02 to the communication slave station 012 via the communication path connected to the communication master station 011 itself. Here, the transmission timing of the routing packet 02 includes the timing at the startup of the distributed control system 01 or the communication master station 011, the occurrence of a failure in the distributed control system 01, a predetermined period, or a regular timing. FIG. 2 is a diagram showing how the routing packet 02 is transferred in the distributed control system 01 in this embodiment. In FIG. 2, the routing packet 02 accumulates the number of times it passes through the communication path. For this purpose, the routing packet 02 is transferred via the communication slave station 012, and each communication slave station 012 receives the routing packet 02. The communication slave station 012 that has received the routing packet updates it by adding 1 to the number of times the communication path included in the routing packet 02 has passed. In this way, each of the communication slave stations 012 counts up the number of times the routing packet 02 has passed and records it in the routing packet 02. In this embodiment, the number of times the communication path has passed is used, but any passing amount in the passing path may be used. As the passing amount, any one of the number of times the communication slave station 012 through which the routing packet 02 has passed from the communication master station 011, the time taken for the routing packet 02 to pass from the communication master station 011, and the physical length through which the routing packet 02 has passed from the communication master station 011 is used. More preferably, it is desirable to use the above-described number of times the communication path has passed and / or the number of times the communication slave station 012 has passed. For example, the sum of the number of times the communication path has passed and the number of times the communication slave station 012 has passed may be used.

[0019] Here, in this embodiment, when the number of times a communication path is passed satisfies a predetermined condition, the passing path is dynamically created and updated. More specifically, when the number of times passed stored in each communication sub-station 012 is less than the specified number of times passed, a passing path is created. Hereinafter, the comparison of the number of times passed will be described. FIG. 3 is a flowchart showing the comparison process of the routing packet 02 by the communication sub-station 012 in this embodiment. This flowchart is executed when the communication sub-station 012 updates, for example, receives the routing packet 02. Note that when the processing subject of this flowchart is described as the communication sub-station 012, unless otherwise specified, each communication sub-station 012 constituting the distributed control system 01 is the processing subject. This is the same for other flowcharts.

[0020] First, in step S30, the communication sub-station 012 determines whether it stores the previous routing packet 02. As a result, if it is positive (YES), the process proceeds to step S31. If it is negative (NO), the process proceeds to step S32.

[0021] Also, in step S31, the communication sub-station 012 determines whether the number of times the communication path of the updated routing packet 02 is less than the number of times the communication path of the routing packet 02 it stores. As a result, if it is positive (YES), the process proceeds to step S32. If the determination is negative (NO), the process ends and returns to the start state. In this step, the number of times the passing path of the updated routing packet 02, which is an example of the first passing amount, is compared with the number of times the passing path of the stored routing packet 02, which is an example of the second passing amount specified before that.

[0022] Also, in step S32, the communication sub-station 012 identifies the updated routing packet 02 and the communication port 0120 through which the routing packet 02 is received. Also, the communication sub-station 012 stores the identified content and preferably transfers it from the remaining communication ports 0120 it has other than the communication port 0120 through which the routing packet 02 is received. Thus, the process ends and returns to the start state.

[0023] Note that, among the number of passes of the previous routing packet 02 in the communication slave station 012, the one with the smallest number of communication path passes is the routing packet 02 that the communication slave station 012 last received or stored (updated). Therefore, the number of passes of the routing packet 02 to be compared in step S31 only needs to be that of the routing packet 02 that the communication slave station 012 last stored. In this embodiment, it is described assuming that the communication slave station 012 stores the previous routing packet 02, but the number of its passes may be stored and used. Note that this also applies to the subsequent descriptions.

[0024] Also, when the communication slave station 012 stores the routing packet 02 and the received communication port 0120 in step S33, it may delete the storage of the previous routing packet 02 and the communication port 0120. Furthermore, the communication slave station 012 only needs to have a storage capacity capable of storing one set of the routing packet 02 and the communication port 0120. Also, when the communication slave station 012 increases the number of communication path passes of the routing packet 02 and transfers it, it will eventually stop being transferred within the distributed control system 01.

[0025] In this embodiment, according to the result of the comparison in FIG. 3, the upstream port is selected and updated from the communication port 0120. This upstream port will constitute the communication path to be created in this embodiment. FIG. 4 is a flowchart showing the selection process of the upstream port of the communication slave station 012 in this embodiment. This process is preferably executed in parallel with the process of the flowchart shown in FIG. 3, but it may also be performed separately.

[0026] In step S40 of FIG. 4, the communication slave station 012 continues to wait for this process until it newly stores or receives the routing packet 02. That is, the communication slave station 012 transitions to step S32 of FIG. 3. When it newly stores or receives the routing packet 02 (YES), it transitions to step S41. When it does not store or receive (NO), it continues step S40.

[0027] Also, in step S41, communication slave station 012 waits for a predetermined communication completion waiting time until the transfer of routing packet 02 in distributed control system 01 is completed. Then, after the waiting, in step S42, communication slave station 012 selects its own last memorized or received communication port 0120 (the first communication port) as the upstream port. At this time, if another communication port 0120 (the second communication port) has been memorized as the upstream port in the past, communication slave station 012 updates this as the communication port selected in this step.

[0028] Also, in step S43, communication slave station 012 transmits an upstream port notification 050 including the upstream port information of the upstream port selected and updated in step S42 from the selected upstream port to the upstream side. Further, in step S44, communication slave station 012 deletes the memorization of routing packet 02 it has memorized and the communication port 0120 where the routing packet 02 was received. With the above, the processing of this flowchart ends and returns to the start state.

[0029] Here, the situation of the transmission and reception (communication) of the upstream port notification 050 transmitted in step S43 in distributed control system 01 will be described. FIG. 5 is a diagram showing the transfer of the upstream port notification 050 of distributed control system 01 in this embodiment. In FIG. 5, the upstream port notification 050 is transferred by other communication slave stations 012 from the transmitting communication slave station 012 to the communication master station 011. That is, the upstream port notification 050 is transferred in the upstream direction. In FIG. 5, communication slave station 012 transmits the upstream port notification 050 from its own upstream port 051. Also, when communication slave station 012 receives the upstream port notification 050 from another communication slave station 012, the processing shown in FIG. 4 ends. Also, when communication slave station 012 returns to the state of waiting for the memorization of a new routing packet 02 in step S40, it transfers the received upstream port notification 050. Otherwise, communication slave station 012 holds the upstream port notification 050 and transfers the trusted upstream port notification 050 after the processing in FIG. 4 ends.

[0030] Also, when performing this transfer, the communication slave station 012 selects its own communication port 0120 that has received the upstream port notification 050 as the downstream port 052. Further, the communication path creation unit 0114 of the communication master station 011 stores the upstream port notifications 050 of the respective communication slave stations 012 received by itself in the upstream port storage unit 0111. Furthermore, the communication path creation unit 0114 of the communication master station 011 creates a communication path with the communication slave station 012 by combining the communication paths to which the upstream ports are connected based on the upstream port information indicated by the stored upstream port notifications 050. Then, the communication path creation unit 0114 stores this in the communication path storage unit 0112.

[0031] According to this embodiment, it is possible to suppress the repeated communication between the communication master station 011 and each communication slave station 012 for creating the communication path between the communication master station 011 and each communication slave station 012 in the distributed control system 01. Also, the communication path between the communication master station 011 and each communication slave station 012 in the distributed control system 01 is constituted by the communication path through which the routing packet 02 is actually transferred. For this reason, for example, even when a communication abnormality due to an initial defect or the like has occurred in the distributed control system 01, the communication path is constituted by the communication path that has avoided the failure.

Example

[0032] Next, Example 2 shows the processing when a failure occurs in the distributed control system 01 as a failure. FIG. 6 is a diagram showing the transfer of the routing packet 02 when the communication slave station 012 has failed in Example 2. In FIG. 6, K1 of the communication slave station 012 of the distributed control system 01 has failed. K1 of the failed communication slave station 012 cannot perform the transfer process of the routing packet 02. For this reason, some of the routing packets 02 shown in FIG. 2 are not transferred. Therefore, in FIG. 6, the routing packet 02 that has passed through K6 of the communication slave station 012 is transferred to K2 to K5.

[0033] Further, FIG. 7 is a diagram showing the transfer of the upstream port notification 050 when the communication slave station 012 in this embodiment fails. By using this upstream port notification 050, the communication path creation unit 0114 will create the communication paths from the communication slave station 012 to K2 to K5 as detour paths including the degenerate communication path 0131 as the communication paths. For example, the communication path of K3 of the communication slave station 012 will be a detour path via K6, K7, K8, and K5 from the communication master station 011. Here, creating such a detour path to avoid the failure leads to identifying the failure location. Therefore, the identification of the failure location in this embodiment will be described.

[0034] FIG. 8 is a flowchart showing the specific process of identifying the failure location of the communication master station 011 in this embodiment. First, the communication master station 011 waits until it receives a new upstream port notification 050 from the communication slave station 012. Then, in step S80, the communication master station 011 determines whether it has received the upstream port notification 050 from the communication slave station 012, that is, whether it has arrived. As a result, if it has arrived (YES), it transitions to step S81. If it has not arrived (NO), step S80 is continued.

[0035] Also, in step S81, the communication master station 011 waits until a predetermined time has elapsed until it finishes receiving the upstream port notification 050 from the communication slave station 012. Then, in step S82, the failure location identification unit 0113 determines whether the upstream port notification 050 has arrived at the communication master station 011 from each communication slave station 012. As a result, if it is positive (YES), it transitions to step S83. If the determination is negative (NO), it transitions to step S84.

[0036] Also, in step S84, the failure location identification unit 0113 identifies the failure location as the communication sub-station 012 where the upstream port notification 050 has not been received. Then, the process ends and returns to the start state. Also, in step S83, the failure location identification unit 0113 determines whether there is a change in the upstream port based on the notified upstream port notification. As a result, if the determination is positive (YES), the process transitions to step S85. Also, if the determination is negative (NO), the process transitions to step S86.

[0037] Also, in step S85, the failure location identification unit 0113 identifies the failure location as the communication path that is closest to the communication master station 011 among the communication paths that have become unused in the communication path. Then, the process ends and returns to the start state. Also, in step S86, the failure location identification unit 0113 determines that there is no failure location, ends the process, and returns to the start state. In this way, when the failure location identification unit 0113 determines that there is no failure location when a communication failure occurs in the distributed control system 01, it can be estimated as a temporary communication abnormality. Also, in this embodiment, since the communication master station 011 does not receive the notification from K1 of the communication sub-station 012, the determination in step S82 becomes negative (NO), and it can be identified as a failure of K1 of the communication sub-station 012 without notification. That is, in steps S84 to S85, the cause of the communication failure occurring in the distributed control system 01 is identified.

[0038] As described above, according to this embodiment, by performing the same processes as those described in the first embodiment, information such as whether each communication sub-station 012 can communicate with the communication master station 011 and which communication path is used if communication is possible is aggregated at the communication master station 011. Therefore, it is possible to identify the failure location, and it is also possible to generate a detour route to the communication sub-station 012 in the distributed control system 01 where a failure has occurred. In addition, the effects when the distributed control system 01 is applied are the same as those in the first embodiment.

Example

[0039] Next, Example 3 adds a display function to Examples 1 and 2. FIG. 9 is a diagram showing a configuration example of the distributed control system 01 in this embodiment. FIG. 9 shows an example after the change process of the upstream port 051 when the normal communication path 0130 between K1 and K2 of the communication slave station 012 is faulty. Here, the communication port of K2 of the communication slave station 012 that is connected to K4 via the fallback communication path 0131 is selected for the upstream port 051. The display device 900 is connected to the communication master station 011 and acquires the communication path information of the distributed control system 01 from the communication master station 011. Here, the display device 900 can be realized by a computer such as a PC or a tablet. Further, the display device 900 may be provided with a control function for controlling the distributed control system 01. Next, the display content on this display device 900 will be described.

[0040] FIG. 10 is a diagram showing a display example on the display device 900 in this embodiment. In FIG. 10, the display screen 1000 of the display device 900 includes a system state display window 1001, a communication path window 1002, and a log monitoring window 1003. Note that these windows are an example of the display area and may be displayed in other modes. Among these windows, the system state display window 1001 displays the network configuration of the distributed control system 01, the failure states of the communication slave station 012 and the communication path. Also, the system state display window 1001 is used for the user to intuitively recognize the failure location and communication path of the distributed control system 01.

[0041] Also, the communication path window 1002 has a function of displaying the connection state of each communication slave station 012, the presence or absence of change in the upstream port, communication path information, etc. Further, the communication path window 1002 is used for the user to analyze the communication slave station 012 affected by the failure that occurred in the distributed control system 01 by displaying the communication paths of each communication slave station 012. The log monitoring window 1003 has a function of displaying the execution time, the communication abnormality detected in the distributed control system 01 which is the reason for execution, and the specified failure location when the communication path generation is executed.

[0042] According to the above-described present embodiment, the distributed control system 01 can notify the user of the failure location, and it is possible to reduce the downtime of the distributed control system 01 and improve the efficiency of maintenance.

[0043] Note that the present invention is not limited to the above-described embodiments, and various modifications and application examples are included. Here, one application example of the present invention will be described. FIG. 11 is a diagram showing an application example of each embodiment. In this application example, the server device 9000 enables management of a plurality of distributed control systems 01. The server device 9000 is connected to the network 9001 and the display device 900. The display device 900 inputs various instructions to the server device 9000 and outputs the processing results of the server device 9000. This output includes the display example of Embodiment 3. Also, the server device 9000 can be realized by a so-called computer and can be referred to as a cloud system. Further, the server device 9000 and the display device 900 may be realized by one device.

[0044] In addition, the server device 9000 is connected to a plurality of distributed control systems 01 via a network 9001 such as the Internet. As a result, the server device 9000 can receive the communication paths created by each distributed control system 01. Note that at least a part of the communication master station 011 in each Embodiment 1 may be executed by the server device 9000. In particular, the creation of the communication path can be executed by the server device 9000. This concludes the description of the application example.

[0045] Each of the above embodiments has been described in detail for easy understanding of the present invention, and is not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, for a part of the configuration of each embodiment, addition, deletion, or replacement with other configurations is possible.

[0046] In addition, each of the above-described configurations, functions, processing units, processing means, etc. may be realized in hardware by designing a part or all of them, for example, in an integrated circuit. Further, each of the above-described configurations, functions, etc. may be realized in software by a processor interpreting and executing a program for realizing each function. Information such as a program, table, file, etc. for realizing each function can be stored in a recording device such as a memory, hard disk, SSD (Solid State Drive), or a recording medium such as an IC card, SD card, DVD. Also, the communication paths are shown as those considered necessary for explanation, and not all communication paths are necessarily shown on the product to which the distributed control system 01 is applied.

[0047] In each of the above embodiments, the communication path of the distributed control system 01 and the detour path in the event of a failure can be generated by the same procedure, and the failure location can be specified. Also, periodic communication for creating the communication path can be suppressed. For this reason, since the communication bandwidth is not compressed, the real-time performance of the control communication can be ensured. Also, since the communication slave station 012 does not need to store the communication path information of communication slave stations other than itself, the storage capacity according to the scale of the distributed control system 01 can be suppressed. Furthermore, in each embodiment, it is not always necessary to perform periodic communication for creating the communication path.

Explanation of Reference Numerals

[0048] 01 Distributed control system 011 Communication master station 0110 Communication port of the communication master station 0111 Upstream port storage unit 0112 Communication path storage unit 0113 Failure location specifying unit 012 Communication slave station 0120 Communication port of the communication slave station 0130 Normal communication path 0131 Degraded communication path 02 Routing packet 050 Upstream port notification 051 Upstream port 052 Downstream port Failure of the 060 Communication Sub-station 900 Display Device 901 Communication Line Failure 1000 Display Screen 1001 System Status Display Window 1002 Communication Route Window 1003 Log Monitoring Window

Claims

1. In a distributed system composed of a communication master station and a plurality of communication slave stations connected in the downstream direction of communication with respect to the communication master station, each of the communication master station and the plurality of communication slave stations is connected to each other via a communication path, each of the plurality of communication slave stations has a plurality of communication ports for performing communication, stores any one of the plurality of communication ports as an upstream port for communicating in the upstream direction, transmits a routing packet from the communication master station to each of the plurality of communication slave stations, in each of the plurality of communication slave stations, identifies a first throughput indicating the throughput of the routing packet from the communication master station, compares the first throughput with a second throughput identified before the identification, which is the second throughput last received by each of the plurality of communication slave stations with the smallest throughput, and determines whether the first throughput is small, in each of the plurality of communication slave stations, identifies a first communication port that has received the routing packet, in each of the plurality of communication slave stations, when the first throughput is small, updates the first communication port as the upstream port, in each of the plurality of communication slave stations, increases the first throughput of the routing packet and transfers it from a communication port provided by the communication slave station itself other than the received communication port, The communication master station creates a communication path from the communication master station in the distributed system by combining each upstream port in the plurality of communication slave stations and the communication path connected to the upstream port. A distributed system.

2. In the distributed system according to claim 1, As the throughput, any one of the number of passes of the communication path through which the routing packet passes, the number of passes of the communication slave station through which the routing packet has passed from the communication master station, the time taken for the routing packet to pass from the communication master station, and the physical length through which the routing packet has passed from the communication master station is used. A distributed system.

3. In the distributed system according to claim 1, in each of the plurality of communication slave stations, when the upstream port is updated to the first communication port, transmits an upstream port notification indicating that the updated first communication port has been selected as the upstream port to the communication master station, The communication master station is a distributed system that generates the communication path using the upstream port notification.

4. In the distributed system according to claim 3, A distributed system in which, when a communication failure occurs in the distributed system, the communication master station transmits the routing packet.

5. In the distributed system according to claim 4, When a communication failure occurs in the distributed system, A distributed system in which the communication master station determines that the cause of the communication failure has occurred in the corresponding communication slave station when there is no upstream port notification for a predetermined period.

6. In the distributed system according to claim 5, A distributed system in which the communication master station receives the upstream port notifications from each of the plurality of communication slave stations, and when the communication path is changed, determines that the cause of the communication failure has occurred in the uppermost communication path among the communication paths before the change.

7. In the distributed system according to claim 5 or 6, A distributed system in which the communication master station creates a detour route that avoids the cause of the communication failure as the communication path.

8. In the distributed system according to claim 3, A distributed system in which each of the plurality of communication slave stations transfers an upstream port notification transmitted from its downstream direction in the upstream direction.

9. In the distributed system according to claim 1, A distributed system in which the communication master station periodically transmits the routing packet.

10. In a communication path creation method in a distributed system including a communication master station and a plurality of communication slave stations connected in a downstream direction of communication with respect to the communication master station, The communication master station and each of the plurality of communication slave stations are connected to each other via a communication path, Each of the plurality of communication slave stations has a plurality of communication ports for performing communication, Any one of the plurality of communication ports is stored as an upstream port for communicating in the upstream direction, The communication master station transmits a routing packet to each of the plurality of communication slave stations, In each of the plurality of communication slave stations, a first throughput indicating the throughput of the routing packet from the communication master station is specified, The first throughput is compared with a second throughput specified before the specification, which is the second throughput last received by each of the plurality of communication slave stations with the smallest throughput, to determine whether the first throughput is small, In each of the plurality of communication slave stations, a first communication port that has received the routing packet is specified, In each of the plurality of communication slave stations, when the first throughput is small, update the first communication port as the upstream port. In each of the plurality of communication slave stations, transfer the routing packet by increasing the first throughput from the communication ports provided in the communication slave station itself other than the received communication port. The communication master station creates a communication path from the communication master station in the distributed system by combining each upstream port in the plurality of communication slave stations and the communication path connected to the upstream port. A communication path creation method in a distributed system.

11. In the communication path creation method in the distributed system according to claim 10, As the throughput, any one of the number of passes of the communication path through which the routing packet passes, the number of passes of the communication slave station through which the routing packet has passed from the communication master station, the time taken for the routing packet to pass from the communication master station, and the physical length through which the routing packet has passed from the communication master station is used. A communication path creation method in a distributed system.

12. In the communication path creation method in the distributed system according to claim 10, In each of the plurality of communication slave stations, when the upstream port is updated to the first communication port, transmit an upstream port notification indicating that the updated first communication port has been selected as the upstream port to the communication master station. A communication path creation method in a distributed system in which the communication master station generates the communication path using the upstream port notification.

13. In the communication path creation method in the distributed system according to claim 12, A communication path creation method in a distributed system in which when a communication failure occurs in the distributed system, the communication master station transmits the routing packet.

14. In the communication path creation method in the distributed system according to claim 13, When a communication failure occurs in the distributed system, The communication master station determines that the cause of the communication failure has occurred in the corresponding communication slave station when the upstream port notification is not received within a predetermined period. A communication path creation method in a distributed system.

15. In the communication path creation method in the distributed system according to claim 14, In a communication path creation method in a distributed system, the communication master station receives the upstream port notifications from each of the plurality of communication slave stations, and when the communication path is changed, determines that the cause of the communication failure has occurred in the uppermost communication path among the communication paths before the change.

16. In the communication path creation method in the distributed system according to claim 14 or 15, In a communication path creation method in a distributed system, the communication master station creates a detour path that avoids the cause of the communication failure as the communication path.

17. In the communication path creation method in the distributed system according to claim 12, In a communication path creation method in a distributed system, at each of the plurality of communication slave stations, an upstream port notification transmitted from its downstream direction is transferred in the upstream direction.

18. In the communication path creation method in the distributed system according to claim 10, In a communication path creation method in a distributed system, the communication master station periodically transmits the routing packet.

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