Communication Systems

Abstract

To perform communication.SOLUTION: A communication system includes a node 101 for storing upper path setting information, a node 102 that is a lower node of the node 101 and stores lower path setting information, and a management device 200 for instructing change of a logical line L11 constructed on a communication path 1 between the node 101 and the node 102. The node 101 changes the logical line L11 of the upper path setting information indicating the correspondence relationship between the communication path 1 and the logical line L11 to a logical line L12 according to an instruction of the management device 200, and transmits the upper path setting information to the node 102. After an abnormality occurs in the communication system and the abnormality is resolved, the node 102 detects that the logical line L12 indicated by the upper path setting information is not coincident with the logical line L11 of the lower path setting information indicating the correspondence relationship between the communication path 1 and the logical line L11, and performs communication with the node 101 via the logical line L12 based on the upper path setting information.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to communication systems. [Background technology]

[0002] 2. Description of the Related Art There are known devices for monitoring a network. For example, a technology for monitoring a network has been proposed (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-91953 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, there are cases where a management device manages a plurality of nodes. The management device manages the plurality of nodes via one of the plurality of nodes. The plurality of nodes are connected via a communication line. A communication path is set on the communication line. The plurality of nodes communicate with each other via the communication path. In addition, a logical line is constructed on the communication line. Therefore, the plurality of nodes communicate via the logical line on the communication path.

[0005] The settings of a logical line on a communication path may be changed at the instruction of a management device. When changing the settings of a logical line, information stored in each node is changed. For example, the information of a higher-level node, which is one of the multiple nodes, and the information of a lower-level node, which is one of the multiple nodes, are changed. This completes the setting change. The lower-level node communicates with the higher-level node based on the information.

[0006] Here, some abnormality may occur after the information in the higher-level node is changed and before the information in the lower-level node is changed. If an abnormality occurs, the lower-level node cannot communicate with the higher-level node because the information in the lower-level node has not been changed.

[0007] The purpose of this disclosure is to communicate. [Means for solving the problem]

[0008] A communication system according to an embodiment of the present disclosure is provided. The communication system includes an upper node that stores upper-level path setting information, a lower node that is a lower node of the upper node and stores lower-level path setting information, and a management device that instructs a change of a first logical line built on a communication path between the upper node and the lower node. The upper node changes the first logical line of the upper node path setting information indicating the correspondence between the communication path and the first logical line to a second logical line in response to an instruction from the management device, and transmits the upper node path setting information to the lower node. After an abnormality occurs in the communication system and the abnormality is resolved, the lower node detects that the second logical line indicated by the upper node path setting information does not match the first logical line of the lower path setting information indicating the correspondence between the communication path and the first logical line, and communicates with the upper node via the second logical line based on the upper node path setting information. Effect of the Invention

[0009] According to the present disclosure, communication can be performed. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 illustrates a communication system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating hardware included in a node according to the first embodiment. [Diagram 3] FIG. 2 is a block diagram showing the functions of a node in the first embodiment. [Figure 4]FIG. 4 is a diagram illustrating an example of path information according to the first embodiment. [Diagram 5] FIG. 4 is a diagram illustrating an example of path setting information according to the first embodiment. [Figure 6] FIG. 11 is a diagram (part 1) showing an example of path setting status information according to the first embodiment. [Figure 7] 4 is a flowchart showing an example of processing executed by a control unit in the first embodiment. [Figure 8] 13 is a flowchart showing an example of a selection process of a logical line according to the first embodiment. [Figure 9] FIG. 4 is a diagram showing a specific example of a setting change in the first embodiment. [Figure 10] 1 is a sequence diagram (part 1) illustrating an example of processing executed in the communication system of the first embodiment. [Figure 11] FIG. 2 is a sequence diagram (part 2) illustrating an example of processing executed in the communication system of the first embodiment. [Figure 12] 13A and 13B are diagrams illustrating an example of changing path setting information in the first embodiment. [Figure 13] FIG. 2 is a diagram (part 2) showing an example of path setting status information according to the first embodiment; [Figure 14] FIG. 3 is a sequence diagram (part 3) illustrating an example of processing executed in the communication system of the first embodiment. [Figure 15] FIG. 11 is a block diagram showing the functions of a node according to a second embodiment. [Figure 16] FIG. 11 is a diagram illustrating an example of a process executed by an allocation unit according to the second embodiment. [Figure 17] 11 is a flowchart showing an example of processing executed by a control unit in the second embodiment. [Figure 18] 11 is a sequence diagram (part 1) illustrating an example of processing executed in a communication system according to a second embodiment. FIG. [Figure 19] FIG. 11 is a sequence diagram (part 2) illustrating an example of processing executed in the communication system according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment will be described with reference to the drawings. The following embodiment is merely an example, and various modifications are possible within the scope of the present disclosure.

[0012] Embodiment 1 1 is a diagram showing a communication system according to a first embodiment. The communication system includes nodes 100, 101, and 102, a management device 200, and terminal devices 300 and 301. The nodes 100, 101, and 102, the management device 200, and the terminal devices 300 and 301 are connected via a communication line. The communication line is a wired line. Alternatively, the communication line may be a wireless line.

[0013] The nodes 100, 101, and 102 have similar functions. Therefore, the nodes will be described mainly using the node 100. The terminal devices 300 and 301 have similar functions. Therefore, the terminal devices will be described mainly using the terminal device 300.

[0014] The node 100 has one or more line ports, one or more terminal ports, and a management port. The node 100 connects to other nodes (e.g., node 101) via the line ports. The node 100 connects to terminal devices (e.g., terminal device 300) via the terminal ports. The node 100 connects to the management device 200 via the management port. The node 100 can multiplex multiple main signals and transmit the multiplexed signal. Here, a main signal is a signal transmitted and received between terminal devices.

[0015] The management device 200 is connected to the node 100 via a communication line. The management device 200 monitors the nodes 100, 101, and 102. The management device 200 manages information related to communication paths. The communication paths will be described later.

[0016] The management device 200 transmits a control signal. The node 100 that is directly connected to the management device 200 via a communication line is called a master station. The nodes 101 and 102 that are not directly connected to the management device 200 via a communication line are called slave stations. The node that receives the control signal can transmit the control signal to an adjacent node (hereinafter, adjacent node). The terminal device 300 transmits and receives main signals via the nodes 100-102.

[0017] Here, a logical line is constructed for the communication line between the nodes. For example, a logical line is constructed for the communication line between node 100 and node 101. Also, for example, a logical line is constructed for the communication line between node 101 and node 102. The construction of a logical line may be considered as follows. For example, when node 100 and node 101 are connected via a wired line, a logical line is constructed on the physical line which is the wired line.

[0018] Moreover, a communication path is represented by a node (also called a relay path, for example), a port, and a logical line. For example, a communication path between terminal device 300 and terminal device 301 is represented by nodes 100, 101, and 102, line ports of node 100 and node 101, a logical line between node 100 and node 101, line ports of node 101 and node 102, a logical line between node 101 and node 102, and terminal ports of node 100 and node 102. In a communication path, a master station is set at the top. The side of the master station is called a master station. The side opposite the master station is called a lower station. For example, when node 101 is a master node, node 102 is a lower node of the master node, and is therefore also called a lower station.

[0019] Next, the hardware of the node 100 will be described. 2 is a diagram showing hardware included in the node of embodiment 1. The node 100 includes a processor 100a, a volatile storage device 100b, and a non-volatile storage device 100c.

[0020] The processor 100a controls the entire node 100. For example, the processor 100a is a central processing unit (CPU) or a field programmable gate array (FPGA). The processor 100a may be a multiprocessor. The node 100 may also have a processing circuit. The processing circuit may be a single circuit or a composite circuit.

[0021] The volatile memory device 100b is a main memory device of the node 100. For example, the volatile memory device 100b is a random access memory (RAM). The non-volatile memory device 100c is an auxiliary memory device of the node 100. For example, the non-volatile memory device 100c is a hard disk drive (HDD) or a solid state drive (SSD).

[0022] Next, the functions of the node 100 will be described. 3 is a block diagram showing functions of a node according to embodiment 1. The node 100 includes circuit IF (Interface) units 120a and 120b, terminal IF units 130a and 130b, a multiplexing unit 140, a path processing unit 150, a generating unit 160, an analyzing unit 170, a management IF unit 180, a control unit 190, and a selecting unit 191.

[0023] Here, the line IF unit 120a and the line IF unit 120b are collectively referred to as the line IF unit 120. Moreover, the terminal IF unit 130a and the terminal IF unit 130b are collectively referred to as the terminal IF unit 130.

[0024] The storage unit 110 may be realized as a storage area secured in the volatile storage device 100b or the non-volatile storage device 100c. A part or all of the line IF unit 120, the terminal IF unit 130, the multiplexing unit 140, the path processing unit 150, the generation unit 160, the analysis unit 170, the management IF unit 180, the control unit 190, and the selection unit 191 may be realized by a processing circuit. Also, a part or all of the line IF unit 120, the terminal IF unit 130, the multiplexing unit 140, the path processing unit 150, the generation unit 160, the analysis unit 170, the management IF unit 180, the control unit 190, and the selection unit 191 may be realized as a module of a program executed by the processor 100a.

[0025] The storage unit 110 stores the path information. An example of the path information is shown below. 4 is a diagram showing an example of path information according to the embodiment 1. Path information 111 is stored in the storage unit 110. The path information 111 is information relating to a path of the node itself on a communication route.

[0026] The path information 111 includes the following items: communication path, upper line port, upper logical line, lower line port, lower logical line, and terminal port. The communication path item indicates a communication path. The upper line port item indicates a line port on the upper side. The upper logical line item indicates an upper logical line. The lower line port item indicates a lower line port. The lower logical line item indicates a lower logical line. The terminal port item indicates a terminal port.

[0027] A line port is represented by a combination of a line port name and a line port number (i.e., a number). For example, a line port is represented by C1. A terminal port is represented by a combination of a terminal port name and a terminal port number (i.e., a number). For example, a terminal port is represented by T1. A logical line is represented by a combination of a logical line name and a logical line number (i.e., a number). For example, a logical line is represented by L1.

[0028] For example, the path information 111 in Fig. 4 indicates that the node 100 exists on the communication path 1. The path information 111 in Fig. 4 indicates that the node 100 is connected to the node 101 via the lower line port C1. The path information 111 in Fig. 4 also indicates that the logical line between the node 100 and the node 101 is L1. The path information 111 in Fig. 4 also indicates that the node 100 is connected to the terminal device 300 via the terminal port T1.

[0029] Returning to FIG. 3, the line IF unit 120 will be described. The line IF unit 120 is an interface for communicating with adjacent nodes. The terminal IF unit 130 is an interface for communicating with the terminal device 300 .

[0030] The multiplexing unit 140 multiplexes a plurality of main signals and a plurality of control signals. The multiplexing unit 140 also multiplexes the main signals and the control signals. When the node 100 receives a multiplexed main signal, the multiplexer 140 separates the multiplexed main signal into multiple main signals. When the node 100 receives a multiplexed control signal, the multiplexer 140 separates the multiplexed control signal into multiple control signals. When the node 100 receives a multiplexed signal, the multiplexer 140 separates the multiplexed signal into a main signal and a control signal.

[0031] The multiplexing unit 140 can receive a control signal including the path information 111 via the line IF unit 120 . The path processing unit 150 determines the output destination of the main signal, the control signal, etc. based on the path information 111. The generating unit 160 can generate a control signal according to an instruction from the control unit 190 .

[0032] The analysis unit 170 analyzes the control signal. The analysis contents include a type indicating a setting request, a response, or a notification, the contents of the setting request, the contents of the response, the contents of the notification, etc. The analysis contents are output to the control unit 190.

[0033] The management IF unit 180 generates a control signal according to an instruction from the control unit 190, and transmits the generated control signal to the management device 200. The management IF unit 180 also receives a control signal from the management device 200. The management IF unit 180 analyzes the received control signal. The analyzed content includes a type indicating a setting request, the content of the setting request, and the like. The analyzed content is output to the control unit 190.

[0034] The management IF unit 180 can receive a control signal including the path information 111. In addition, the management IF unit 180 transmits and receives to and from the management device 200 information such as a type indicating a setting request, a response, or a notification, the contents of the setting request, the contents of the response, and the contents of the notification.

[0035] The control unit 190 receives the path information 111 from the management IF unit 180. In addition, the control unit 190 receives the path information 111 from the multiplexing unit 140 via the analysis unit 170. The control unit 190 stores the received path information 111 in the storage unit 110. In addition, the control unit 190 can transmit the path information 111 to the path processing unit 150. The control unit 190 instructs the line IF unit 120 to transmit the path setting information to the adjacent node via the generation unit 160 and the multiplexing unit 140. An example of the path setting information will now be given.

[0036] 5 is a diagram showing an example of path setting information according to the embodiment 1. The path setting information 112 is stored in the storage unit 110. The path setting information 112 has items of line port, logical line, path, and communication route.

[0037] The line port item indicates the line port. The logical line item indicates the logical line. The path item indicates whether a path is set or not. For example, "path present" indicates that a path is set and therefore signals can be sent and received. "path absent" indicates that a path is not set and therefore signals cannot be sent and received. The communication path item indicates the communication path.

[0038] For example, the path setting information 112 in Fig. 4 indicates that a line port C1 exists on the communication path 1. The path setting information 112 in Fig. 4 also indicates that the nodes 100 and 101 can communicate with each other via the line port C1 and the logical line L1 (i.e., there is a path).

[0039] Furthermore, the control unit 190 receives path setting information 112 from the adjacent node via the line IF unit 120. The control unit 190 creates path setting status information based on the path setting information 112 of its own node and the path setting information 112 of the adjacent node. The control unit 190 also creates path setting status information using path information 111. An example of the path setting status information is given below.

[0040] Fig. 6 is a diagram (part 1) showing an example of path setting status information in the first embodiment. On the left side of Fig. 6, path setting information 112 of the own node (i.e., node 100) is depicted. On the right side of Fig. 6, path setting information 112 of the adjacent node (i.e., node 101) is depicted. The path setting status information 113 has the items of circuit port, logical line, direction, communication path, and matching status.

[0041] The information in the items of circuit port, logical line, and communication path is information in the path setting information 112 of the own node. The information in the item of direction is specified using the path information 111. For example, using the path information 111, it is specified whether the line port C1 is a lower line port or not. The information in the matching status item is created based on the local node's path setting information 112 and the adjacent node's path setting information 112. The information in the matching status item will be explained below.

[0042] An explanation will be given for "Path Exists, Match" in the record of logical line L1 in path setting status information 113. "Path Exists" indicates that "Path Exists" is registered in the path item of path setting information 112 of the own node. "Match" indicates that the path settings match because the path item of path setting information 112 of the own node is "Path Exists" and the path item of path setting information 112 of the adjacent node is "Path Exists".

[0043] An explanation will be given of "Path Existing, Mismatch" in the record of logical line L2 in path setting status information 113. "Path Existing" indicates that "Path Existing" is registered in the path item of path setting information 112 of the own node. "Mismatch" indicates that the path setting does not match because the path item of path setting information 112 of the own node is "Path Existing" and the path item of path setting information 112 of the adjacent node is "No Path".

[0044] An explanation will be given for "no path, match" in the record of logical line L3 in path setting status information 113. "No path" indicates that "no path" is registered in the path item of path setting information 112 of the own node. "Match" indicates that the path item of path setting information 112 of the own node is "no path" and the path item of path setting information 112 of the adjacent node is "no path", so that there is a match in that no path is set.

[0045] Next, the process executed by the control unit 190 will be described with reference to a flowchart. FIG. 7 is a flowchart illustrating an example of a process executed by the control unit according to the first embodiment. (Step S11) The control unit 190 determines whether or not the control signal to be transmitted is a response to a request for setting, acquiring, etc. If the control signal is the response, the process proceeds to step S12. If the control signal is the request, the process proceeds to step S13.

[0046] (Step S12) The control unit 190 selects the logical line used when the control signal indicating the request was received. The fact that the control signal indicating the request is received means that the logical line used when the control signal indicating the request was received is available. (Step S13) The control unit 190 judges whether or not the destination is a lower level. If the destination is a lower level, the process proceeds to step S14. If the destination is a higher level, the process proceeds to step S15.

[0047] (Step S14) The control unit 190 selects a lower logical line based on the path information 111. (Step S15) The control unit 190 instructs the selection unit 191 to select a logical line. The selection unit 191 selects a logical line in accordance with the instruction. The selection process of a logical line will be described with reference to a flowchart.

[0048] FIG. 8 is a flowchart illustrating an example of a selection process of a logical line according to the first embodiment. (Step S21) The selection unit 191 refers to the matching status of the path setting status information 113. The selection unit 191 judges whether or not "path exists, matching" exists. If "path exists, matching" exists, the process proceeds to step S22. If "path exists, matching" does not exist, the process proceeds to step S23.

[0049] (Step S22) The selection unit 191 selects one of the upper logical lines from the records of the path setting status information 113 that indicate "path exists, match." (Step S23) The selection unit 191 determines whether or not "path exists, mismatch" exists. If "path exists, mismatch" exists, the process proceeds to step S24. If "path exists, mismatch" does not exist, the process proceeds to step S25.

[0050] (Step S24) The selection unit 191 selects a logical line with a "path present" from the path setting information 112 of the adjacent node. (Step S25) The selection unit 191 determines that it is not possible to select a logical line. After the control unit 190 or the selection unit 191 selects a logical line, the control unit 190 instructs the generation unit 160 to generate a control signal for transmission via the selected logical line.

[0051] Next, the setting change will be specifically described. Fig. 9 is a diagram showing a specific example of a setting change in the first embodiment. A communication path 1 is set on the nodes 100 to 102 in Fig. 9. It is assumed that no other communication paths are set on the nodes 100 to 102. The setting change is performed in response to an instruction from the management device 200.

[0052] Fig. 9 shows that the logical line L11 corresponding to the line port C3 of the node 101 is changed to the logical line L12. More specifically, the logical line L11 of the path information 111 of the node 101 is changed to the logical line L12. Fig. 9 also shows that the logical line L11 corresponding to the line port C4 of the node 102 is changed to the logical line L12. More specifically, the logical line L11 of the path information 111 of the node 102 is changed to the logical line L12.

[0053] Here, for example, the setting change is completed in the node 101, but the setting change is not completed in the node 102, and some abnormality occurs. For example, the abnormality is a failure of the nodes 100, 101, and 102, a failure of the communication line between the node 100 and the node 101, or a failure of the communication line between the node 101 and the node 102. In this way, when an abnormality occurs, the node 102 cannot communicate with the node 101. The reason for the inability to communicate will be explained in detail. The logical line corresponding to the communication path 1 of the path information 111 of the node 102 is the logical line L11. Therefore, the node 102 communicates via the logical line L11. For example, the node 102 transmits a main signal via the logical line L11. However, the logical line corresponding to the communication path 1 of the path information 111 of the node 101 is the logical line L12. Therefore, the main signal does not reach the node 101. Furthermore, even if the main signal reaches node 101, node 101 discards the main signal because the communication is not via logical line L12. Thus, node 102 cannot communicate with node 101. Furthermore, if node 101 and node 102 cannot communicate with each other, management device 200 cannot detect that the setting change in node 102 is incomplete. Therefore, hereinafter, a case where node 101 and node 102 can communicate with each other will be described.

[0054] FIG. 10 is a sequence diagram (part 1) illustrating an example of processing executed in the communication system according to the first embodiment. (Step ST101) The management device 200 transmits a control signal including change path information to the node 100. The change path information 111 is information for changing the path information 111 of the node 101. The change path information 111 is called change path information. The change path information indicates a communication path "1", an upper line port "C2", an upper logical line "L1", a lower line port "C3", and a lower logical line "L12".

[0055] In this way, the management device 200 transmits a control signal including the path information 111 for change to the node 100. In other words, the management device 200 instructs to change the logical line L11 established on the communication path between the node 101 and the node 102. Here, the logical line L11 is also called a first logical line. The logical line L12 is also called a second logical line.

[0056] The control unit 190 of the node 100 receives the control signal via the management IF unit 180 .

[0057] (Step ST102) The control unit 190 refers to the path information 111 and selects the logical line L1, which is a lower logical line. The control unit 190 instructs the generation unit 160 to generate a control signal to be transmitted to the logical line L1. The control signal is a control signal for a setting request. The control signal includes path information for change.

[0058] The generating unit 160 generates a control signal for the setting request. The multiplexing unit 140 multiplexes the control signal. The multiplexing unit 140 instructs the lower line port C1 to transmit the multiplexed data (hereinafter, multiplexed data).

[0059] (Step ST103) The line port C1 transmits the multiplexed data to the node 101 via the logical line L1.

[0060] (Step ST104) The multiplexing unit of the node 101 receives the multiplexed data via the upper line port C2. The multiplexing unit separates the setting request control signal from the multiplexed data. The analysis unit of the node 101 analyzes the setting request control signal. The analysis unit analyzes that the control signal is a setting request control signal of the path information 111 stored in the node 101.

[0061] The control unit of the node 101 changes the path information 111 stored in the node 101 based on the change path information included in the control signal. As a result, the lower logical line "L11" in the path information 111 stored in the node 101 is changed to the lower logical line "L12."

[0062] (Step ST105) The control unit of the node 101 selects the higher-level logical line (that is, the logical line L1) that was used when the control signal (more specifically, the multiplexed data) was received. The control unit of the node 101 instructs the generation unit of the node 101 to generate a response control signal. The control signal includes information indicating that the setting change has been successful (hereinafter, setting change success information).

[0063] A generating unit of the node 101 generates the control signal. A multiplexing unit of the node 101 multiplexes the control signal. The multiplexing unit instructs the upper line port C2 to transmit the multiplexed data.

[0064] (Step ST106) The line port C2 transmits the multiplexed data to the node 100 via the logical line L1.

[0065] (Step ST107) The multiplexing unit 140 receives the multiplexed data via the lower line port C1. The multiplexing unit 140 separates the response control signal from the multiplexed data. The analysis unit 170 analyzes the response control signal. The analysis unit 170 analyzes that the control signal includes setting change success information. The control unit 190 instructs the management IF unit 180 to transmit the setting change success information included in the control signal. The management IF unit 180 transmits the setting change success information to the management device 200.

[0066] FIG. 11 is a sequence diagram (part 2) illustrating an example of the process executed in the communication system according to the first embodiment. (Step ST111) The control unit of the node 101 starts control based on the path information 111 stored in the node 101. That is, the control unit of the node 101 starts control based on the path information 111 changed in step ST104.

[0067] (Step ST112) The control unit of the node 101 refers to the changed path information 111 and selects the logical line L12, which is a lower logical line. The control unit of the node 101 changes the path setting information 112 stored in the storage unit of the node 101. Here, an example of changing the path setting information 112 will be described.

[0068] 12(A) and (B) are diagrams showing an example of changing path setting information according to the embodiment 1. In the path information 111 in FIG. 12(A) and (B), the item of the terminal port is omitted. Path information 111 in Fig. 12(A) is the pre-change path information 111. Path setting information 112 in Fig. 12(A) is the pre-change path setting information 112. For example, the path setting information 112 indicates the correspondence relationship between the communication path 1 and the logical line L11.

[0069] The path information 111 before the change is changed to the path information 111 in Fig. 12(B) by being changed in step ST104. The control unit of the node 101 changes the path setting information 112 in Fig. 12(A) based on the changed path information 111. In other words, the control unit of the node 101 changes the logical line L11 corresponding to the communication route 1 in the path setting information 112 to the logical line L12 in response to an instruction from the management device 200. As a result, the path setting information 112 in Fig. 12(A) is changed to the path setting information 112 in Fig. 12(B).

[0070] Returning to FIG. 11, the process will be described. Since the path information 111 of the node 102 is the same as before the change, the control unit of the node 101 refers to the path information 111 before the change (that is, the path information 111 in FIG. 12(A)) and selects the logical line L11, which is the lower logical line.

[0071] The control unit of the node 101 instructs the generation unit of the node 101 to generate a control signal to be transmitted to the logical line L11. The control signal includes the changed path setting information 112 (i.e., the path setting information 112 in FIG. 12(B)). The generating unit generates the control signal. The multiplexing unit of the node 101 multiplexes the control signal. The multiplexing unit instructs the lower line port C3 to transmit multiplexed data.

[0072] (Step ST113) The line port C3 transmits the multiplexed data to the node 102 through the logical line L11. As a result, the changed path setting information 112 is transmitted to the node 102.

[0073] (Step ST114) The multiplexing unit of the node 102 receives the multiplexed data via the upper line port C4. The multiplexing unit separates the control signal from the multiplexed data. The analysis unit of the node 102 analyzes the control signal. The analysis unit analyzes that the control signal includes the path setting information 112.

[0074] The control unit of the node 102 creates path setting status information 113 based on the path setting information 112 of the node itself (i.e., the path setting information 112 stored in the storage unit of the node 102) and the path setting information 112 of the adjacent node (i.e., the path setting information 112 included in the control signal). An example of the created path setting status information 113 is shown below.

[0075] Fig. 13 is a diagram (part 2) showing an example of path setting status information in the first embodiment. On the left side of Fig. 13, path setting information 112 of the own node (i.e., node 102) is depicted. Here, the path setting information 112 of node 102 is also referred to as lower-level path setting information. The path setting information 112 of node 102 indicates the correspondence relationship between the communication route 1 and the logical line L11.

[0076] 13, the path setting information 112 of the adjacent node (that is, the node 101) is depicted on the right side. Here, the path setting information 112 of the node 101 is also referred to as higher-level path setting information. The control unit of the node 102 creates path setting status information 113 based on the two pieces of path setting information 112 .

[0077] Returning to FIG. 11, the process will be described. (Step ST115) The selection unit of node 102 refers to the matching status item of path setting status information 113 and identifies that communication route 1 is "path exists, mismatch". The selection unit of node 102 selects a logical line L12 (i.e., a higher-level logical line) on which a path is set based on path setting information 112 of an adjacent node. The selection unit notifies the control unit of node 102 of information on the selected logical line L12.

[0078] (Step ST116) Due to some abnormality, the setting change process managed by the management device 200 is interrupted. In other words, it is assumed that an abnormality has occurred in the communication system. After the interruption, it is assumed that the abnormality is resolved. For example, when a failure occurs in the node 100, it is assumed that the node 100 has recovered.

[0079] FIG. 14 is a sequence diagram (part 3) illustrating an example of the process executed in the communication system according to the first embodiment. (Step ST121) The control unit of node 102 refers to the matching status item of path setting status information 113 and determines that communication path 1 is "path exists, mismatch". That is, the control unit detects that the logical line L12 indicated by path setting information 112 of node 101 does not match the logical line L11 of path setting information 112 of node 102. In other words, the control unit detects that the logical lines in communication path 1 do not match. Since it is "mismatch", the control unit determines that communication path 1 is abnormal.

[0080] (Step ST122) The control unit of the node 102 instructs the generation unit of the node 102 to generate a notification control signal. The control signal is a control signal addressed to the node 100. The control signal is a signal including the path setting status information 113. Here, the path setting status information 113 may not have a direction item. The path setting status information 113 included in the control signal may not include information of "no communication path". For example, the record of the logical line L13 in the path setting status information 113 of FIG. 13 may not be included in the path setting status information 113 included in the control signal. The path setting status information 113 may be expressed as follows. The path setting status information 113 is information indicating that the path has not been changed in the node 102, information indicating that the logical line used when the node 102 communicates with the node 101 has not been changed, or information indicating that the logical line on the communication path managed by the node 102 has not been changed.

[0081] The generating unit generates the control signal. The multiplexing unit of the node 102 multiplexes the control signal. The multiplexing unit instructs the upper line port C4 to transmit the multiplexed data via the logical line L12 selected in step ST115. The multiplexing unit may specify the logical line L12 again based on the path setting information 112 of the node 101, and then instruct the line port C4 to transmit. The line port C4 transmits the multiplexed data to the node 100 via the logical line L12, the node 101, and the logical line L1.

[0082] In this way, after the abnormality is resolved, the node 102 communicates with the node 101 via the logical line L12 based on the path setting information 112 of the node 101.

[0083] (Step ST123) The management IF unit 180 separates the notification control signal from the multiplexed data. The management IF unit 180 transmits the path setting status information 113 included in the control signal to the management device 200. This enables the management device 200 to detect that the setting change in the node 102 is incomplete.

[0084] (Step ST124) The management device 200 displays the path setting status information 113 on the display. This allows the user to recognize by looking at the display that the setting change has not been completed in the node 102. After this, for example, the user manually changes the setting of the node 102.

[0085] Also, in step ST113, it has been explained that the path setting information 112 is transmitted when the path information 111 is changed. The path setting information 112 may be transmitted periodically. It has been explained that the path setting information 112 is transmitted to the lower node in step ST113. The path setting information 112 may also be transmitted to the upper node. In step ST122, a case has been described in which a control signal including the path setting status information 113 is transmitted. The control signal may include information other than the path setting status information 113.

[0086] As described above, according to the first embodiment, the node 102 can communicate with the node 101. In addition, since the nodes 101 and 102 can communicate with each other, the management device 200 can detect, via the nodes 100 and 101, that the setting change in the node 102 is incomplete.

[0087] Embodiment 2 Next, a description will be given of embodiment 2. In embodiment 2, differences from embodiment 1 will be mainly described. In embodiment 2, descriptions of matters common to embodiment 1 will be omitted.

[0088] Fig. 15 is a block diagram showing the functions of a node according to the embodiment 2. The components in Fig. 15 that are the same as those in Fig. 3 are given the same reference numerals as those in Fig. 3. The node 100 further includes an allocation unit 192. A part or the whole of the allocation unit 192 may be realized by a processing circuit. Also, a part or the whole of the allocation unit 192 may be realized as a module of a program executed by the processor 100a.

[0089] The allocation unit 192 identifies a logical line based on the path setting status information 113. Furthermore, the allocation unit 192 transmits a transmission instruction for the multiplexed data to the line IF unit 120. Furthermore, the allocation unit 192 transmits a stop instruction for the multiplexed data to the line IF unit 120. Note that the transmission instruction and the stop instruction include information indicating the identified logical line.

[0090] When the line IF unit 120 receives a transmission instruction, it starts transmitting the multiplexed data via the logical line instructed by the allocation unit 192. When the line IF unit 120 receives a stop instruction, it stops transmitting the multiplexed data via the logical line instructed by the allocation unit 192.

[0091] Next, the process of identifying a logical line, issuing a transmission instruction, and issuing a stop instruction by the allocation unit 192 will be described with reference to a flowchart. FIG. 16 is a diagram showing an example of processing executed by the allocation unit of the second embodiment. Here, the minimum logical line will be explained. The minimum logical line is a logical line that is used even when the number of logical lines established on the communication path is one. In other words, the minimum logical line is a logical line that is always established on the communication path. The minimum logical line is a preset logical line. In the following explanation, the minimum logical line is assumed to be logical line L1.

[0092] (Step S31) The allocation unit 192 identifies a logical line with a path based on the path setting status information 113. That is, the allocation unit 192 identifies a logical line with a path in the node 100. The allocation unit 192 determines whether the identified logical line with a path is the logical line L1 (that is, the minimum logical line). If the logical line L1 has a path, the process proceeds to step S32. If the logical line L1 does not have a path, the process proceeds to step S33.

[0093] (Step S32) The allocation unit 192 transmits a transmission instruction for the multiplexed data to the line IF unit 120 via the logical line L1. (Step S33) The allocation unit 192 judges whether the path identified in step S31 is a lower logical line. If the path is a lower logical line, the process proceeds to step S34. If the path is a higher logical line, the process proceeds to step S35.

[0094] (Step S34) The allocation unit 192 transmits a transmission instruction for the multiplexed data to the line IF unit 120 via the lower logical line. (Step S35) The allocation unit 192 determines whether the matching status corresponding to the path existence identified in step S31 is a match, based on the path setting status information 113. If the matching status is a match, the process proceeds to step 36. If the matching status is a mismatch, the process proceeds to step 37.

[0095] (Step S36) The allocation unit 192 transmits to the line IF unit 120 a transmission instruction for the multiplexed data via the higher-level logical line having the path identified in step S31. (Step S37) The allocation unit 192 determines whether or not there is a "path present, mismatch" based on the path setting status information 113. If there is a "path present, mismatch", the process proceeds to step S38. If there is no "path present, mismatch", the process proceeds to step S39.

[0096] (Step S38) The allocation unit 192 selects a logical line with a path from the path setting information 112 of the adjacent node. The allocation unit 192 transmits an instruction to the line IF unit 120 to transmit the multiplexed data via the selected logical line. (Step S39) The allocation unit 192 transmits an instruction to the line IF unit 120 to stop the multiplexed data.

[0097] Next, the process executed by the control unit 190 will be described with reference to a flowchart. Fig. 17 is a flowchart showing an example of processing executed by a control unit in embodiment 2. The processing in Fig. 17 differs from the processing in Fig. 7 in that steps S12a and 12b are executed. Therefore, steps S12a and 12b will be described in Fig. 17. Descriptions of processing other than steps S12a and 12b will be omitted.

[0098] (Step S12a) The control unit 190 judges whether or not the control signal that was the subject of judgment in step S11 is a control signal to be transmitted to an adjacent node. If the condition is satisfied, the process proceeds to step S12b. If the condition is not satisfied, the process proceeds to step S13. (Step S12b) The control unit 190 selects the minimum logical interface.

[0099] Next, the process executed in the communication system will be described with reference to a sequence diagram. In the following process, the description of the process common to Figs. 10, 11, and 14 will be omitted. FIG. 18 is a sequence diagram (part 1) illustrating an example of processing executed in the communication system according to the second embodiment. (Step ST112a) The control unit of the node 101 refers to the changed path information 111 and selects the logical line L12, which is a lower logical line. The control unit of the node 101 changes the path setting information 112 stored in the storage unit of the node 101. The allocation unit of the node 101 transmits a transmission instruction for the multiplexed data via the logical line L12 to the circuit IF unit of the node 101. The circuit IF unit 120 starts transmitting the multiplexed data via the logical line L12.

[0100] (Step ST112b) The control unit of the node 101 selects the logical line L11, which is the minimum logical line. The control unit of the node 101 instructs the generation unit of the node 101 to generate a control signal to be transmitted to the logical line L11. The control signal includes the changed path setting information 112 (i.e., the path setting information 112 in FIG. 12(B)). The generating unit generates the control signal. The multiplexing unit of the node 101 multiplexes the control signal. The multiplexing unit instructs the lower line port C3 to transmit multiplexed data.

[0101] FIG. 19 is a sequence diagram (part 2) illustrating an example of the process executed in the communication system according to the second embodiment. (Step ST121a) The allocation unit of the node 102 identifies the logical line L12 with a path based on the path setting information 112 (i.e., the path setting information 112 in FIG. 12(B)) of the adjacent node (i.e., the node 101). The allocation unit of the node 102 transmits an instruction to transmit the multiplexed data via the logical line L12 to the circuit IF unit of the node 102. The circuit IF unit starts transmitting the multiplexed data via the logical line L12.

[0102] For example, node 102 detects a matching state of logical lines on a communication path based on path setting information 112 of node 101 and path setting information 112 of node 102. Based on the matching state, node 102 performs transmission control to transmit a signal to node 101 and stop control of a signal being transmitted to node 101. In detail, the line IF unit of node 102 transmits multiplexed data in response to a transmission instruction and stops transmitting the multiplexed data in response to a stop instruction. According to the second embodiment, the node can control transmission and stop of multiplexed data in accordance with the path setting state.

[0103] The features of each of the embodiments described above can be combined with each other as appropriate. [Explanation of symbols]

[0104] 100, 101, 102 nodes, 100a processor, 100b volatile storage device, 100c non-volatile storage device, 110 storage unit, 111 path information, 112 path setting information, 113 path setting status information, 120, 120a, 120b line IF unit, 130, 130a, 130b terminal IF unit, 140 multiplexing unit, 150 path processing unit, 160 generation unit, 170 analysis unit, 180 management IF unit, 190 control unit, 191 selection unit, 192 allocation unit, 200 management device, 300, 301 terminal devices.

Claims

1. 1. A communication system comprising: an upper node that stores upper path setting information; a lower node which is a lower node of the upper node and stores lower path setting information; a management device that instructs a change of a first logical line established on a communication path between the upper node and the lower node; Including, The upper node is changing the first logical line in the higher-level path setting information indicating a correspondence between the communication path and the first logical line to a second logical line in response to an instruction from the management device; Transmitting the upper level path setting information to the lower level node; The lower node is detecting, after an abnormality occurs in the communication system and the abnormality is resolved, that the second logical line indicated by the higher-level path setting information does not match the first logical line of the lower-level path setting information indicating a correspondence relationship between the communication path and the first logical line; performing communication with the upper node via the second logical line based on the upper path setting information; Communication systems.

2. one or more nodes including the upper node, The management device is connected to any one of the one or more nodes, the lower node transmits, via the one or more nodes, information indicating that the path has not been changed at the lower node to the management device; The communication system according to claim 1 .

3. the lower node detects a matching state of logical lines on the communication path based on the upper path setting information and the lower path setting information, and performs a transmission control for transmitting a signal to the upper node and a stop control for the signal being transmitted to the upper node based on the matching state.

3. A communication system according to claim 1 or 2.

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