JP2009165053A - Communication device, communication control method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively use a band in a redundant system. <P>SOLUTION: The communication device has: an input/output Interfaces(IF) to be communicated with one or more information processors (devices); a Switch(SW) for connecting the output IF to a first transfer passage of a Ring type Network and the input IF from the device or the input IF from a second transfer passage to each other; a means for monitoring the condition of the input IF from the device or of the output IF to the device; a means for notifying another communication device of a monitoring status at a predetermined timing; and an SW control means. The control means controls the SW to connect the output IF to the first transfer passage and the input IF from the second transfer passage to each other, if detecting a failure during a time when the SW connects the output IF to the first transfer passage and the input IF from the device to each other. It controls the SW to connect the output IF to the first transfer passage and the input IF from the device to each other, if it is not notified of the monitoring status for a certain time or longer by another communication device during a time when the SW connects the output IF to the first transfer passage and the input IF from the second transfer passage, to each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a communication device for a ring network, and more particularly to a technique for enabling effective use of a band in a ring network having a redundant configuration.

  In a system that requires high reliability, in addition to a center station that manages normal operation, a backup station that manages operation when a failure occurs in the center station is often provided to provide redundancy. When constructing such a system, a ring network using a transmission path shared by each station may be employed.

  FIG. 1A shows an example of a ring network in which a certain base station, a center station, and a backup station are connected. In such a ring network, when data is transmitted from the base station to the center station, the address of the center station is set in the transmission destination address (for example, the transmission destination address in the IP header), and data is transmitted from the base station to the backup station. When transmitting, it is necessary to set the address of the backup station as the destination address. Therefore, as shown in FIG. 2, when switching from the operation by the center station to the operation by the backup station, the base station must change the transmission destination address. However, since there are many base stations and there are also unmanned base stations, it is difficult to operate each base station to switch the transmission destination when switching the operation station. As a transmission technique for the ring network, there is a technique such as RPR (Resilient Packet Ring).

  On the other hand, there is a case where a dedicated line for communication between the base station and the center station and a dedicated line for communication between the base station and the backup station are separately prepared to construct the system as described above. In this case, for example, as shown in FIG. 1B, a path 102 that connects the base station and the center station in a fixed manner and a path 103 that connects the base station and the backup station in a fixed manner are constructed. For example, when data flows from the base station to the path 102, the path 102 connects the base station and the center station in a fixed manner, so that the data is transmitted to the center station regardless of the setting of the transmission destination address. Therefore, when switching the operation station, it is not necessary to change the transmission destination address in each base station, but it is necessary to switch the path.

  In addition, when individually constructing a communication line, in consideration of reliability, it is possible to occupy a fixed band and occupy dedicated high-speed digital or SONET / SDH instead of a wide area Ethernet (registered trademark) line or the like. A transmission line is often used. Further, as a countermeasure against a transmission path failure or the like, a ring configuration using two cables (for clockwise / counterclockwise) is often employed and a bypass route is often provided.

  For example, FIG. 3 shows a conventional system configuration when a detour route is provided. In the example of FIG. 3, the conventional system includes a center station communication device, a backup station communication device, a base A communication device,... To form a ring network. In each station, a communication device and a terminal device are connected by a primary group interface (for example, an ISDN (Integrated Services Digital Network) line). In the example of FIG. 3, only the communication line related to the base A is illustrated, but the base station other than the base A also has a communication line (normal system and detour route) with the center station and the backup station. Communication lines (normal system and detour route) are individually constructed.

  FIG. 4 shows a data flow in each of the base A, the center station, and the backup station shown in FIG. In the example of FIG. 4, it is assumed that the transmission path IF (R) in the communication apparatus of each station is connected to the clockwise transmission path, and the transmission path IF (L) is connected to the counterclockwise transmission path. Also, arrows 401 and 402 in FIG. 4 represent data flowing through the communication line between the base A and the center station, and arrows 403 and 404 represent data flowing through the communication line between the base A and the backup station.

  When the operation is performed by the center station, the data from the terminal device of the base A is transmitted to the transmission path in both directions via the terminal IF (A) of the base A and the transmission paths IF (R) and (L). The data is output and sent to the terminal device of the center station via the transmission lines IF (R) and (L) of the center station and the terminal IF. On the other hand, the data from the terminal device of the center station is output to the transmission path in both directions via the terminal IF of the center station and the transmission paths IF (R) and (L), and the transmission path IF (R) of the base A And (L) and the terminal IF (A), it is sent to the terminal device at the site A. Further, data transmitted / received between the base A and the center station passes through the communication device of the backup station. Note that when the operation is performed by the center station, the communication line between the base A and the backup station is not used.

  In addition, when the operation is performed by the backup station, the data from the terminal device at the base A is transmitted in both directions via the terminal IF (B) at the base A and the transmission paths IF (R) and (L). To the terminal device of the backup station via the transmission paths IF (R) and (L) of the backup station and the terminal IF. On the other hand, the data from the terminal device of the backup station is output to the transmission path in both directions via the terminal IF of the backup station and the transmission paths IF (R) and (L), and the transmission path IF (R of the base A ) And (L) and the terminal IF (B) to the terminal device at the site A. Further, data transmitted and received between the base A and the backup station passes through the communication device of the center station. Note that the receiving side communication device receives data from the transmission path in both directions, but selects one of the data at the terminal IF (terminal IF (A) and (B) at the base A) of the communication device, and the terminal Output to the device. Note that when the operation is performed by the backup station, the communication line between the base A and the center station is not used.

  As described above, in the conventional system configuration, although the base station uses only one communication line (communication line with the operation station) for communication, the transmission path connecting the stations has 2 It is necessary to secure the bandwidth for the line. For example, when connecting between stations using transmission line equipment owned by a telecommunications carrier, one communication line (communication line with a non-operating station) is not used, but two lines of bandwidth are required. Therefore, it will cost.

For example, Japanese Patent Laid-Open No. 62-258536 discloses a ring network configuration control system. Specifically, a ring abnormality was detected in a ring network system comprising a plurality of concentrators connected by a ring-shaped transmission line and at least one terminal station connected to each concentrator via a branch line. The line concentrator disconnects all branch lines under its jurisdiction from the ring-shaped transmission line, and performs internal diagnosis to identify abnormal locations in a state where other line concentrators can communicate on the ring-shaped transmission line. ing. According to the technique described in the publication, if an abnormality is detected, the terminal is disconnected from the ring-shaped transmission line, so that it may be possible to immediately return to a normal communication state, but the above problem cannot be solved. .
JP-A-62-258536

  As described above, in a system having a redundant configuration, if the communication line with the operation station and the communication line with the non-operation station are individually constructed, each base station can be switched even if the operation station is switched. You do not need to change the destination address. However, in the prior art, it is necessary to secure a bandwidth of a communication line that is not used, and the bandwidth cannot be effectively used.

  Accordingly, an object of the present invention is to provide a technique for enabling effective use of bandwidth in a system having a redundant configuration.

  Furthermore, another object of the present invention is to provide a technique for enabling operation stations to be switched without changing the transmission destination address in each base station in a system having a redundant configuration.

  A communication apparatus according to the present invention is a communication apparatus for a ring network, and includes an input interface and an output interface for communicating with one or more information processing apparatuses, and an output interface to a first transmission path in the ring network. In addition, a switch that selectively connects an input interface from the information processing apparatus or an input interface from a second transmission path different from the first transmission path in the ring network, and an input interface and information from the information processing apparatus Control unit for monitoring whether the state of the output interface to the processing device is normal, state notification unit for notifying other communication devices in complementary relationship of the monitoring status by the monitoring unit at a predetermined timing, and controlling the switch Switch control means. When the switch control means detects an abnormality by the monitoring means while the switch connects the output interface to the first transmission path and the input interface from the information processing apparatus, the switch control means goes to the first transmission path. Means for controlling the switch to connect the input interface from the second transmission line to the output interface of the second transmission line, and the switch connects the output interface to the first transmission line and the input interface from the second transmission line. During this time, if the notification of the monitoring status from another communication device has not been made for a certain period of time, the switch is controlled so that the input interface from the information processing device is connected to the output interface to the first transmission path. Means.

  In this way, for example, by changing the connection in the switch between the operation time and the non-operation time, it becomes possible to construct a system having a redundant configuration with one communication line. That is, since it is not necessary to secure the bandwidth for two lines, the cost can be suppressed. In addition, since the monitoring status is communicated between the communication devices and control is performed to change the connection in the switch when an abnormality is detected, the operation station can be automatically switched.

  In addition, when the status notification unit detects an abnormality by the monitoring unit while the switch connects the output interface to the first transmission path and the input interface from the information processing apparatus, You may make it have a means to notify a communication apparatus. When the switch control means receives a connection switching request from another communication device while the switch connects the output interface to the first transmission path and the input interface from the second transmission path. The switch may further include means for controlling the switch so as to connect the input interface from the information processing apparatus to the output interface to the first transmission path.

  In this way, for example, when an abnormality occurs in the information processing device of the operation station, the communication device of the operation station takes the lead and the operation station can be automatically switched.

  In addition, the input interface from the second transmission path and the output interface to the information processing apparatus may be connected regardless of the connection state of the switch.

  In this way, even if the base station is switched at each base station, it is not necessary to switch the transmission destination address. Note that data from the base station is also transmitted to the information processing apparatus of the non-operation station, but there is no problem.

  According to the present invention, it is possible to effectively use a band in a system having a redundant configuration.

  Further, according to another aspect of the present invention, in a system having a redundant configuration, operation stations can be switched without changing the transmission destination address in each base station.

  FIG. 5 shows a system overview according to an embodiment of the present invention. In the example of FIG. 5, this system has a center station, a backup station, and n base stations (base A,..., Base n in FIG. 5) connected by a transmission line such as an optical fiber. Form a ring network. In the present embodiment, it is assumed that a ring configuration using two optical fiber cables (for clockwise or counterclockwise) is adopted. In each station, the communication device and the terminal device are connected by, for example, a primary group interface (for example, an ISDN line). The number of terminal devices is not limited to one, and a plurality of terminal devices may be connected to the communication device.

  In this embodiment, in the system shown in FIG. 5, a dedicated line for communication between the base station, the center station, and the backup station is prepared for each base station, and the operation is performed as described later. When the station is switched, the connection in the communication apparatus of the center station and the communication apparatus of the backup station is switched. The operation of the communication device of the center station and the communication device of the backup station will be briefly described with reference to FIGS.

  FIG. 6A shows a communication line related to the base A when the center station is operating. At this time, as shown in FIG. 6B, the communication device of the center station outputs the data for the base A received from the terminal device of the center station to the transmission path in both directions. Then, in the communication device at the site A, the same data is received from the transmission lines in both directions, and one data is selected and output to the terminal device at the site A. In FIG. 6B, for communication from the center station to the site A, the one selected as the communication device at the site A is shown as regular and the other is shown as a bypass route.

  Furthermore, when the data for the center station is received from the transmission path in both directions, the center station communication device selects one of the data and outputs it to the terminal device of the center station. In FIG. 6B, for communication from the base A to the center station, the one selected in the communication apparatus of the center station is shown as normal, and the other is shown as a bypass route.

  On the other hand, when the operation is performed by the center station, the communication device of the backup station outputs the data sent from the transmission path on the center station side to the transmission path on the base A side, and from the transmission path on the base A side. The sent data is output to the transmission line on the center station side.

  In addition, FIG. 7A shows a communication line related to the base A when the operation is performed by the backup station. At this time, as shown in FIG. 7B, the backup station communication apparatus outputs the data for the base A received from the backup station terminal apparatus to the transmission lines in both directions. Then, in the communication device at the site A, the same data is received from the transmission lines in both directions, and one data is selected and output to the terminal device at the site A. In FIG. 7B, for the communication from the backup station to the site A, the one selected as the communication device at the site A is shown as regular and the other is shown as a bypass route.

  Further, when the backup station communication device receives the data for the backup station from the two-way transmission path, the backup station communication device selects one of the data and outputs it to the terminal device of the backup station. In FIG. 7B, for communication from the base A to the backup station, the one selected in the communication apparatus of the backup station is shown as regular and the other is shown as a bypass route.

  On the other hand, when the operation is performed by the backup station, the communication device of the center station outputs the data sent from the transmission path on the backup station side to the transmission path on the base A side, and from the transmission path on the base A side. The sent data is output to the transmission path on the backup station side.

  That is, in the communication device of the non-operation station, data from the base station to the operation station and data from the operation station to the base station are allowed to pass through.

  In the system shown in FIG. 5, the data flow in each of the base station, the operation station, and the non-operation station is shown in FIG. In FIG. 8, a station in the operating state among the center station and the backup station is represented as an operating station, and the other station (non-operating state) is represented as a non-operating station. In addition, the communication device of the operation station and the communication device of the non-operation station each have a changeover switch unit, and, as will be described below, switching between when operating as an operation station and when operating as a non-operation station Switch the connection in the switch.

  For example, in the base station, data from the terminal device of the base station is output to the transmission path in both directions via the terminal IF of the base station and the transmission paths IF (R) and (L). Note that, for example, an FCS (Frame Check Sequence) is added to the data from the terminal device of the base station at the terminal IF of the base station. The data from the operation station is sent from the bidirectional transmission path to the base station terminal device via the base station transmission paths IF (R) and (L) and the terminal IF. The terminal IF checks the normality of the data based on the FCS assigned to the data, selects one data, and outputs it to the terminal device. In the base station, the same operation is performed regardless of whether the center station or the backup station is operated.

  In the operation station, the terminal IF and the transmission path IF (R) are connected so that the first changeover switch in the communication apparatus outputs the input from the terminal apparatus to the clockwise transmission path. Further, the terminal IF and the transmission path IF (L) are connected so that the second changeover switch unit in the communication apparatus outputs the input from the terminal apparatus to the counterclockwise transmission path. Therefore, the data from the terminal device of the operation station is transmitted in both directions via the terminal IF of the operation station, the first changeover switch unit and the second changeover switch unit, and the transmission paths IF (R) and (L). Is output to the road. The FCS is added to the data from the terminal of the operation station at the terminal IF of the operation station.

  Further, the transmission paths IF (R) and (L) of the operation station and the terminal IF are connected so that the communication apparatus outputs the input from the transmission path in both directions to the terminal apparatus. Accordingly, data from the base station is sent from the bidirectional transmission path to the terminal apparatus of the operation station via the transmission paths IF (R) and (L) of the operation station and the terminal IF. The terminal IF checks the normality of the data based on the FCS assigned to the data, selects one data, and outputs it to the terminal device.

  On the other hand, in the non-operation station, the input and output of the transmission path IF (R) are connected by the first changeover switch unit in the communication device. Further, the input and output of the transmission path IF (L) are connected at the second changeover switch unit in the communication device. Accordingly, the data from the base station and the data from the operation station are transmitted to the non-operation station transmission paths IF (R) and (L), the first changeover switch section and the second changeover switch section, and the transmission path IF (R). And (L) through the non-operating station. Since the first changeover switch unit and the second changeover switch unit are not connected to output the input from the terminal device to the transmission line, the data from the terminal device of the non-operating station is output to the transmission line. It will never be done.

  Further, the transmission lines IF (R) and (L) of the operation station and the terminal IF are connected so that the input from the transmission line in both directions is output to the terminal device in the communication device. For this reason, data from other stations is sent from the bidirectional transmission path to the non-operating station terminal device via the non-operating station transmission paths IF (R) and (L) and the terminal IF. Since the terminal device is in a non-operating state, no problem occurs.

  Next, a specific configuration in the center station and the backup station is shown in FIG. In the example of FIG. 9, the center station and the backup station communicate with the communication device 11 that performs the main processing in the present invention, the terminal device 13 that transmits and receives data with the terminal device of the base station via the communication device 11, A monitoring control device 15 that monitors and controls the device 11 and a switching control device 17 that instructs the communication device 11 to perform manual switching.

  Further, the communication device 11 includes a first transmission path interface unit 111, a first route setting unit 112, a first changeover switch unit 113, a second transmission path interface unit 114, a second route setting unit 115, It has the 2nd changeover switch part 116, the terminal interface part 117 used as the interface with the terminal device 13, and the monitoring control part 118 which monitors the state of the communication apparatus 11. FIG. The first transmission path interface unit 111 and the second transmission path interface unit 114 are, for example, an optical interface or an electrical interface, and are connected to the transmission path. Further, the first changeover switch unit 113 and the second changeover switch unit 116 have the switch function as described above, and follow the manual switching instruction from the switching control device 17 or the switching instruction from the monitoring control unit 118. Switch connection. Further, the first route setting unit 112 is connected to the first transmission line interface unit 111, the first changeover switch unit 113, and the terminal interface unit 117, and the first transmission is performed on the basis of preset data. The information is output to any one of the road interface unit 111, the first changeover switch unit 113, and the terminal interface unit 117. Similarly, the second path setting unit 115 is connected to the second transmission path interface unit 114, the second changeover switch unit 116, and the terminal interface unit 117, and inputs the input data based on the preset data. The data is output to any one of the transmission path interface unit 114, the second changeover switch unit 116, and the terminal interface unit 117. Further, the first transmission path interface unit 111, the first route setting unit 112, and the first changeover switch unit 113 serve as a data communication path in one direction (clockwise or counterclockwise), and the second transmission path interface unit 114. The second route setting unit 115 and the second changeover switch unit 116 serve as data communication paths in the reverse direction.

  Next, using FIG. 10 and FIG. 11, a state implemented between the communication device 11 of the operation station (hereinafter referred to as communication device 11A) and the communication device 11 of the non-operation station (hereinafter referred to as communication device 11B). The monitoring process will be described. As shown in FIG. 10, apart from data transmitted and received between the operation station and the base station, data for state monitoring is exchanged between the communication device 11A (operation station) and the communication device 11B (non-operation station). . Specifically, the monitoring control unit 118 of the communication device 11A transmits a state confirmation notification for notifying that its own state is normal to the communication device 11B, and resets the state confirmation timer (FIG. 11: Step S1).

  On the other hand, the monitoring control unit 118 of the communication device 11B receives the state confirmation notification from the communication device 11A (step S3). Then, the monitoring control unit 118 of the communication device 11B transmits a state confirmation notification to the communication device 11A, and resets the state confirmation timer (step S5).

  On the other hand, the communication device 11A receives the state confirmation notification from the communication device 11B (step S7). Then, the processing from step S1 to step S7 is repeated. For example, when a state confirmation notification is received from the partner side before the state confirmation timer times out, the partner side state is determined to be normal.

  Next, a process when a failure occurs in the terminal device 13 or the terminal interface unit 117 of the operation station will be described with reference to FIG. First, the monitoring control unit 118 of the communication device 11A detects a failure of the terminal device 13 or the terminal interface unit 117 of the operation station (FIG. 12: step S11). Thereafter, the monitoring control unit 118 of the communication device 11A transmits a switching confirmation notification to the communication device 11B, and starts a switching confirmation timer (step S13). At this time, the monitoring control unit 118 of the communication device 11A may output to the monitoring control device 15 that a failure has been detected.

  On the other hand, the monitoring control unit 118 of the communication device 11B receives the switching confirmation notification from the communication device 11A (step S15). Then, when the terminal device 13 and the terminal interface unit 117 of the non-operation station are operating normally, the monitoring control unit 118 of the communication device 11B transmits a switching confirmation response to the communication terminal 11A (step S17).

  Then, the monitoring control unit 118 of the communication device 11A receives the switching confirmation response from the communication device 11B, and stops the switching confirmation timer (step S19). Thereafter, the monitoring control unit 118 of the communication device 11A outputs a switching instruction to the first changeover switch unit 113 and the second changeover switch unit 116 of the communication device 11A. Then, in response to the switching instruction, the first changeover switch unit 113 and the second changeover switch unit 116 of the communication device 11A perform a switching process (step S21). Specifically, the first changeover switch unit 113 of the communication device 11A receives data input from the transmission line via the first transmission line interface unit 111 and the first route setting unit 112 as a first route setting unit. The connection is switched so as to be output to the first transmission path interface unit 111 via 112. Similarly, the second changeover switch unit 116 of the communication device 11A receives data input from the transmission line via the second transmission line interface unit 114 and the second route setting unit 115, and the second route setting unit 115. The connection is switched so as to be output to the second transmission path interface unit 114 via the network. Then, after performing the connection process, the monitoring control unit 118 of the communication device 11A transmits a switch completion notification to the communication device 11B (step S23).

  Then, the monitoring control unit 118 of the communication device 11B receives the switch completion notification from the communication device 11A (step S25). Thereafter, the monitoring control unit 118 of the communication device 11B outputs a switching instruction to the first changeover switch unit 113 and the second changeover switch unit 116 of the communication device 11B. Then, in response to the switching instruction, the first switching switch unit 113 and the second switching switch unit 116 of the communication device 11B perform switching processing (step S27). Specifically, the first changeover switch unit 113 of the communication device 11B receives data input from the transmission line via the first transmission line interface unit 111 and the first route setting unit 112 as the first route setting unit. The connection is switched so as to be output to the terminal interface unit 117 via 112. Similarly, the second changeover switch unit 116 of the communication device 11B receives data input from the transmission line via the second transmission line interface unit 114 and the second route setting unit 115, and the second route setting unit 115. The connection is switched so as to be output to the terminal interface unit 117 via the terminal.

  By performing the processing as described above, the operation station can be automatically switched when a failure occurs in the terminal device 13 or the terminal interface unit 117 of the operation station.

  Although not shown in the figure, when there is a failure in the terminal device 13 or the terminal interface unit 117 of the non-operating station when the switching confirmation notification is received from the operating station, the non-operating station transmits a switching confirmation response. do not do. For this reason, the operation station detects a timeout of the switching confirmation timer. In this case, if the terminal device 13 or the terminal interface unit 117 of the operation station has been recovered, the operation must be continued and recovered. In this case, the monitoring control device 15 is informed that the operation station cannot be switched.

  Next, processing when a failure occurs in the communication apparatus 11A of the operation station will be described with reference to FIG. As shown in FIG. 11, when the communication device 11A is operating normally, the monitoring control unit 118 of the communication device 11A transmits a state confirmation notification to the communication device 11B and resets the state confirmation timer. (FIG. 13: Step S31). In the present embodiment, it is assumed that a failure occurs in the communication device 11A after transmitting the state confirmation notification (step S33).

  On the other hand, the monitoring control unit 118 of the communication device 11B receives the state confirmation notification from the communication device 11A (step S35). Then, the monitoring control unit 118 of the communication device 11B transmits a state confirmation notification to the communication device 11A, and resets the state confirmation timer (step S37).

  Then, the monitoring control unit 118 of the communication device 11A receives the state confirmation notification from the communication device 11B (step S39). However, since this step may not be processed correctly due to a failure that has occurred in the communication device 11A, it is a dotted block in FIG.

  Thereafter, the monitoring control unit 118 of the communication device 11B detects a timeout of the state confirmation timer (step S41). Then, the monitoring control unit 118 of the communication device 11B determines whether the number of retransmissions of the state confirmation notification has exceeded a predetermined number (step S43). If the number of retransmissions of the status confirmation notification does not exceed the predetermined number of times (step S43: No route), the monitoring control unit 118 of the communication device 11B retransmits the status confirmation notification to the communication device 11A after a predetermined time has elapsed, The timer is reset (step S45).

  Then, the monitoring control unit 118 of the communication device 11A receives the state confirmation notification from the communication device 11B (step S47). However, since this step may not be processed correctly due to a failure that has occurred in the communication device 11A, it is a dotted block in FIG.

  Then, the monitoring control unit 118 of the communication device 11B determines whether or not a state confirmation notification has been received from the communication device 11A before detecting the time-out of the state confirmation timer (step S49). If a status confirmation notification is received from the communication device 11A before detecting the time-out of the status confirmation timer (step S49: Yes route), the monitoring control unit 118 of the communication device 11B resets the number of retransmissions and further checks the status. The timer is reset (step S51). On the other hand, if the status confirmation notification is not received from the communication device 11A before detecting the timeout of the status confirmation timer (step S49: No route), the processing returns to step S41.

  On the other hand, when it is determined in step S43 that the number of retransmissions of the status confirmation notification has exceeded the predetermined number (step S43: Yes route), the monitoring control unit 118 of the communication device 11B indicates that some failure has occurred in the communication device 11A. Judgment is made, and a switching instruction is output to the first changeover switch unit 113 and the second changeover switch unit 116 of the communication device 11B. Then, in response to the switching instruction, the first changeover switch unit 113 and the second changeover switch unit 116 of the communication device 11B perform a switching process (step S53). Note that the switching process is the same as the process of step S27, and thus the description thereof is omitted here.

  By performing the processing as described above, even when a failure occurs in the communication device 11A of the operation station, the operation station can be automatically switched.

  Next, processing when a failure occurs in the communication apparatus 11B of the non-operation station will be described with reference to FIG. It is assumed that the operation station is operating normally. As shown in FIG. 11, when the communication device 11B is operating normally, the monitoring control unit 118 of the communication device 11B transmits a state confirmation notification to the communication device 11A and resets the state confirmation timer. (FIG. 14: Step S61). In this embodiment, it is assumed that a failure occurs in the communication device 11B after transmitting the state confirmation notification (step S63).

  On the other hand, the monitoring control unit 118 of the communication device 11A receives the state confirmation notification from the communication device 11B (step S65). Then, the monitoring control unit 118 of the communication device 11A transmits a state confirmation notification to the communication device 11B and resets the state confirmation timer (step S67).

  Then, the monitoring control unit 118 of the communication device 11B receives the state confirmation notification from the communication device 11A (step S69). However, since this step may not be processed correctly due to a failure that has occurred in the communication device 11B, it is a dotted block in FIG.

  Thereafter, the monitoring control unit 118 of the communication device 11A detects a time-out of the state confirmation timer (step S71). Then, the monitoring control unit 118 of the communication device 11A resends the state confirmation notification to the communication device 11B after a predetermined time has elapsed, and resets the state confirmation timer (step S73).

  Then, the monitoring control unit 118 of the communication device 11B receives the state confirmation notification from the communication device 11A (step S75). However, since this step may not be processed correctly due to a failure that has occurred in the communication device 11B, it is a dotted block in FIG.

  In addition, the monitoring control unit 118 of the communication device 11A repeats the processes of step S71 and step S73. Note that since the communication device 11A operates normally, no problem occurs in the operation of the system.

  In the above, the processing when a failure occurs in the communication device 11 or the terminal device 13 has been described. However, for example, when a failure occurs in the communication line (normal system) between the operation station and the base station, as shown in FIG. In addition, the communication line that was the detour route is used as a regular communication line. In this case, since the operation station is operating normally, the operation station is not switched.

  As described above, according to the present embodiment, the bandwidth can be effectively used in the system having the redundant configuration, and it is not necessary to secure the bandwidth for two lines. That is, since a system can be constructed with a half band compared to the conventional one, the cost for communication can be reduced. Furthermore, the base station can exchange data without being aware of the switching of the operation station.

  Although one embodiment of the present invention has been described above, the present invention is not limited to this. For example, although FIG. 9 illustrates an example in which the monitoring control device 15 and the switching control device 17 are provided separately, they may be integrated.

  Also, for example, depending on the system, there is a case where the operation station does not have to be switched immediately because a failure occurs in the operation station. In this case, the operation is performed after waiting for a manual switching instruction from the user. You may make it switch a station.

(Appendix 1)
A communication device for a ring network,
An input interface and an output interface for communicating with one or more information processing apparatuses;
The input interface from the information processing apparatus to the output interface to the first transmission path in the ring network or the input interface from a second transmission path different from the first transmission path in the ring network A switch to selectively connect,
Monitoring means for monitoring whether the status of the input interface from the information processing apparatus and the output interface to the information processing apparatus is normal;
Status notification means for notifying other communication devices in a complementary relationship of the monitoring status by the monitoring means at a predetermined timing;
Switch control means for controlling the switch;
Have
The switch control means;
When an abnormality is detected by the monitoring means while the switch connects the output interface to the first transmission path and the input interface from the information processing apparatus, the switch to the first transmission path Means for controlling the switch to connect an input interface from the second transmission line to an output interface;
While the switch connects the output interface to the first transmission path and the input interface from the second transmission path, the monitoring status is notified from the other communication device for a predetermined time or more. If not, means for controlling the switch to connect the input interface from the information processing device to an output interface to the first transmission path;
A communication apparatus comprising:

(Appendix 2)
The status notification means
If an abnormality is detected by the monitoring means while the switch connects the output interface to the first transmission path and the input interface from the information processing apparatus, a connection switching request is sent to the other communication. Means for notifying the device,
The switch control means;
When the switch receives the connection switching request from the other communication device while connecting the output interface to the first transmission path and the input interface from the second transmission path, The communication apparatus according to claim 1, further comprising means for controlling the switch so as to connect the input interface from the information processing apparatus to an output interface to the first transmission path.

(Appendix 3)
The communication apparatus according to appendix 1, wherein an input interface from the second transmission path and the output interface to the information processing apparatus are connected regardless of a connection state of the switch.

(Appendix 4)
An input interface and an output interface for communicating with one or more information processing apparatuses, an output interface to a first transmission path in a ring network, and the input interface from the information processing apparatus or the ring network in the ring network. A communication control method executed by a communication device for a ring network having a switch that selectively connects an input interface from a second transmission line different from the first transmission line,
A monitoring step of monitoring whether the state of the input interface from the information processing apparatus and the output interface to the information processing apparatus is normal;
When an abnormality is detected by the monitoring step while the switch connects the output interface to the first transmission path and the input interface from the information processing apparatus, the switch includes the first interface Directing the output interface to the transmission path to connect the input interface from the second transmission path;
While the switch connects the output interface to the first transmission path and the input interface from the second transmission path, the notification of the monitoring status from a complementary communication device for a certain time or more If not, instructing the switch to connect the input interface from the information processing device to an output interface to the first transmission path;
Including a communication control method.

(Appendix 5)
An input interface and an output interface for communicating with one or more information processing apparatuses, an output interface to a first transmission path in a ring network, and the input interface from the information processing apparatus or the ring network in the ring network. A program for causing a communication device for a ring network to execute processing, which includes a switch that selectively connects an input interface from a second transmission line different from one transmission line,
A monitoring step of monitoring whether the state of the input interface from the information processing apparatus and the output interface to the information processing apparatus is normal;
When an abnormality is detected by the monitoring step while the switch connects the output interface to the first transmission path and the input interface from the information processing apparatus, the switch includes the first interface Directing the output interface to the transmission path to connect the input interface from the second transmission path;
While the switch connects the output interface to the first transmission path and the input interface from the second transmission path, the notification of the monitoring status from a complementary communication device for a certain time or more If not, instructing the switch to connect the input interface from the information processing device to an output interface to the first transmission path;
Including a communication control program.

(A) And (b) is a figure for demonstrating the prior art in the case of constructing | assembling the system provided with the redundancy structure. It is a figure for demonstrating switching of the operation station in the conventional system. It is a figure which shows the structural example of the conventional system. It is a figure for demonstrating the flow of the data in the conventional system. It is a system configuration figure concerning an embodiment of the invention. (A) And (b) is a figure for demonstrating the outline | summary of the system which concerns on embodiment of this invention. (A) And (b) is a figure for demonstrating the outline | summary of the system which concerns on embodiment of this invention. It is a figure for demonstrating the flow of the data in the system which concerns on embodiment of this invention. It is a figure which shows the structure of a center station / backup station. It is a figure for demonstrating the exchange between an operation station and a non-operation station. It is a figure for demonstrating the process for confirming a state between communication apparatuses. It is a figure for demonstrating the process when a failure generate | occur | produces in the terminal device or terminal interface part of an operation station. It is a figure for demonstrating the process when a failure generate | occur | produces in the communication apparatus of an operation station. It is a figure for demonstrating the process when a failure generate | occur | produces in the communication apparatus of a non-operation station. It is a figure which shows a regular system and a detour route when a failure occurs in a communication line between a base station and an operation station.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Communication apparatus 13 Terminal apparatus 15 Monitoring control apparatus 17 Switching control apparatus 111 1st transmission path interface part 112 1st path setting part 113 1st changeover switch part 114 2nd transmission path interface part 115 2nd path setting part 116 1st 2 changeover switch unit 117 terminal interface unit 118 monitoring control unit

Claims (5)

A communication device for a ring network,
An input interface and an output interface for communicating with one or more information processing apparatuses;
The input interface from the information processing apparatus to the output interface to the first transmission path in the ring network or the input interface from a second transmission path different from the first transmission path in the ring network A switch to selectively connect,
Monitoring means for monitoring whether the status of the input interface from the information processing apparatus and the output interface to the information processing apparatus is normal;
State notification means for notifying other communication devices in a complementary relationship of the monitoring status by the monitoring means at a predetermined timing;
Switch control means for controlling the switch;
Have
The switch control means;
When an abnormality is detected by the monitoring means while the switch connects the output interface to the first transmission path and the input interface from the information processing apparatus, the switch to the first transmission path Means for controlling the switch to connect an input interface from the second transmission line to an output interface;
While the switch connects the output interface to the first transmission path and the input interface from the second transmission path, the monitoring status is notified from the other communication device for a predetermined time or more. If not, means for controlling the switch to connect the input interface from the information processing device to an output interface to the first transmission path;
A communication apparatus comprising: The status notification means
If an abnormality is detected by the monitoring means while the switch connects the output interface to the first transmission path and the input interface from the information processing apparatus, a connection switching request is sent to the other communication. Means for notifying the device,
The switch control means;
When the switch receives the connection switching request from the other communication device while connecting the output interface to the first transmission path and the input interface from the second transmission path, The communication apparatus according to claim 1, further comprising means for controlling the switch so as to connect the input interface from the information processing apparatus to an output interface to the first transmission path. The communication apparatus according to claim 1, wherein an input interface from the second transmission path and the output interface to the information processing apparatus are connected regardless of a connection state of the switch. An input interface and an output interface for communicating with one or more information processing apparatuses, an output interface to a first transmission path in a ring network, and the input interface from the information processing apparatus or the ring network in the ring network. A communication control method executed by a communication device for a ring network having a switch that selectively connects an input interface from a second transmission line different from the first transmission line,
A monitoring step of monitoring whether the state of the input interface from the information processing apparatus and the output interface to the information processing apparatus is normal;
When an abnormality is detected by the monitoring step while the switch connects the output interface to the first transmission path and the input interface from the information processing apparatus, the switch includes the first interface Directing the output interface to the transmission path to connect the input interface from the second transmission path;
While the switch connects the output interface to the first transmission path and the input interface from the second transmission path, the notification of the monitoring status from another communication device in a complementary relationship is longer than a certain time. If not, instructing the switch to connect the input interface from the information processing device to an output interface to the first transmission path;
Including a communication control method. An input interface and an output interface for communicating with one or more information processing apparatuses, an output interface to a first transmission path in a ring network, and the input interface from the information processing apparatus or the ring network in the ring network. A program for causing a communication device for a ring network to execute processing, which includes a switch that selectively connects an input interface from a second transmission line different from one transmission line,
A monitoring step of monitoring whether the state of the input interface from the information processing apparatus and the output interface to the information processing apparatus is normal;
When an abnormality is detected by the monitoring step while the switch connects the output interface to the first transmission path and the input interface from the information processing apparatus, the switch includes the first interface Directing the output interface to the transmission path to connect the input interface from the second transmission path;
While the switch connects the output interface to the first transmission path and the input interface from the second transmission path, the notification of the monitoring status from a complementary communication device for a certain time or more If not, instructing the switch to connect the input interface from the information processing device to an output interface to the first transmission path;
Including a communication control program.

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