Terminal equipment and switching control method

Abstract

In the present invention, in a first communication device: a first terminal device terminates a signal between the same and a first lower level device; a first transmission / reception unit transmits / receives a main signal of a second lower level device to / from a second communication device; and a first control unit performs first switching control to switch to a spare first terminal device if an abnormality has occurred in the first terminal device. In the second communication device: a second terminal device terminates a signal between the same and the second lower level device; a second transmission / reception unit transmits, through the second terminal device, a main signal received from the first transmission / reception unit and transmits a main signal received by the second terminal device to the first communication device; and a second control unit performs switching to a spare second terminal device if an abnormality has occurred in the second terminal device in operation. The first control unit performs second switching control if a second monitoring control unit of the second communication device issues notification that an abnormality has occurred in the second control unit and the second terminal device, and the second control unit performs the first switching control if a first monitoring control unit of the first communication device issues notification that an abnormality has occurred in the first control unit and the first terminal device.

Description

[Technical Field]

[0001] The present invention relates to a terminal device reference and a switching control method. [Background technology]

[0002] PON protection is a technology to improve the reliability of PON (Passive Optical Network), which provides redundancy to the devices that make up the PON.

[0003] Figure 8 shows an example of PON protection. The OLT (Optical Line Terminal) shown in Figure 8 has N+1 OSUs (Optical Subscriber Units) inside. Each of the N OSUs is connected to an ONU (Optical Network Unit) via a different PON line. The OSU terminates the optical signal between the ONU and the ONU. If an OSU currently connected to an ONU stops working due to a failure or other reason, the ONU's connection can be switched to a spare OSU via an N × (N + 1) optical switch. Switching to the spare OSU allows communication to continue without interrupting the service provided to the ONU. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-121038 Summary of the Invention [Problem to be solved by the invention]

[0005] In rural areas, an OLT or OSU is often deployed. However, the above-mentioned conventional technology applies to a configuration in which the OLT and ONU are directly connected. Furthermore, the above-mentioned conventional technology does not specify how to control PON protection for the OLT or OSU at the deployment destination.

[0006] In view of the above circumstances, the present invention provides a terminal device capable of providing redundancy to devices used for transmitting and receiving signals in a terminal device with an extended configuration. reference The present invention aims to provide a switching control method. [Means for solving the problem]

[0007] One aspect of the present invention is an end station device comprising a first communication device and a second communication device, wherein the first communication device comprises a redundant first terminal device that terminates signals between a first lower-level device and the second lower-level device, a first transceiver unit that transmits and receives a main signal of a source or destination to and from the second communication device, a first control unit that performs first switching control to switch the first terminal device in operation where an abnormality has occurred to a spare first terminal device when an abnormality has occurred in the first terminal device, and a first monitoring control unit that monitors the state of the first control unit, and the second communication device comprises a redundant second terminal device that terminates signals between the second lower-level device and the second lower-level device, and a process of transmitting the main signal received from the first transceiver unit to the second lower-level device via the second terminal device. and a second transceiver that performs processing for transmitting a main signal received by the second terminal device from the second lower-level device to the first communication device; a second control unit that performs second switching control to switch the second terminal device in which an abnormality has occurred to a spare second terminal device when an abnormality occurs in the second terminal device during operation; and a second monitoring control unit that monitors the status of the second control unit, wherein the first control unit performs the second switching control when notified by the second monitoring control unit of the occurrence of an abnormality in the second control unit and the occurrence of an abnormality in the second terminal device during operation, and the second control unit performs the first switching control when notified by the first monitoring control unit of the occurrence of an abnormality in the first control unit and the occurrence of an abnormality in the first terminal device during operation.

[0008] A communication device according to one embodiment of the present invention comprises a redundant termination device that terminates signals between lower-level devices, a relay unit that relays main signals whose source or destination is a lower-level device subordinate to another communication device, a control unit that performs switching control to switch the abnormal termination device to a spare termination device when an abnormality occurs in the termination device during operation, and a monitoring control unit that outputs a notification when an abnormality occurs in the control unit and when an abnormality occurs in the termination device during operation, and receives the switching control from another communication device that has received the notification of the abnormality in the control unit and the notification of the abnormality in the termination device during operation.

[0009] A switching control method according to one aspect of the present invention is a switching control method in an end station device having a first communication device and a second communication device, the method including: a first transmission / reception step in which a first terminal device in operation among redundant first terminal devices of the first communication device transmits and receives a signal to and from a first lower-level device; a second transmission / reception step in which a first transmission / reception unit of the first communication device transmits and receives a main signal having a second lower-level device as a source or destination to and from the second communication device; a first switching step in which a first control unit of the first communication device performs first switching control in the event of an abnormality occurring in the first terminal device in operation, to switch the abnormal first terminal device to a spare first terminal device; a third transmission / reception step in which a second terminal device in operation among redundant second terminal devices of the second communication device transmits and receives a signal to and from the second lower-level device; a process in which a second transmission / reception unit of the second communication device receives the main signal transmitted in the second transmission / reception step and transmits the received main signal to the second lower-level device via the second terminal device; a fourth transmitting / receiving step of performing a process of transmitting the abnormality to the second terminal device; a second switching step of performing a second switching control by a second control unit of the second communication device when an abnormality occurs in the second terminal device during operation, to switch the second terminal device in which an abnormality has occurred to the spare second terminal device; a first notification step of a first monitoring and control unit of the first communication device when an abnormality occurs in the first control unit and when an abnormality occurs in the first terminal device during operation, to notify the second communication device of the occurrence of an abnormality; a third switching step of performing the first switching control by the second control unit of the second communication device when the notification of the occurrence of an abnormality in the first control unit and when an abnormality occurs in the first terminal device during operation; a second notification step of a second monitoring and control unit of the second communication device when an abnormality occurs in the second control unit and when an abnormality occurs in the second terminal device during operation, to notify the first communication device of the occurrence of an abnormality; [Effects of the Invention]

[0010] According to the present invention, it is possible to provide redundancy to devices used for transmitting and receiving signals in a terminal device with a remote configuration. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a configuration diagram of a terminal device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a configuration diagram of a master station and an optical selector according to the embodiment. [Figure 3] FIG. 2 is a diagram illustrating the configuration of a slave station according to the embodiment. [Figure 4] FIG. 2 is a block diagram showing functions of a master station and a slave station according to the embodiment. [Figure 5] FIG. 10 is a flowchart showing the processing of the terminal device according to the embodiment. [Figure 6] FIG. 2 is a diagram illustrating the operation of the terminal device according to the embodiment. [Figure 7] FIG. 2 is a diagram illustrating the operation of the terminal device according to the embodiment. [Figure 8] FIG. 1 illustrates conventional PON protection. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the same parts in the multiple drawings are given the same reference numerals and the description thereof will be omitted.

[0013] The terminal device of this embodiment has a configuration in which multiple OLTs or OSUs, which are partial functions of the OLTs, are hierarchically connected. The hierarchically connected OLTs have a relationship of master station and slave station. The OLT of the master station (hereinafter referred to as master station) and the OLT of the slave station (hereinafter referred to as slave station) are equipped with a control panel and a transfer PKG (package). The transfer PKG transfers main signals between the master station and the slave station. The transfer PKG also has a control unit and has the function of sending and receiving control signals used by the control unit. This allows the master station and the slave station to mutually utilize the control panels and control units in the transfer PKGs installed in each station, as well as the systems that control and monitor the master station and the slave station, to switch to a redundant PON-PKG in the event of a malfunction in the PON-PKG equipped with the PON interface of the OSU. Furthermore, control signals are sent and received between the master station and the slave station using the same transmission path as the main signal.

[0014] According to this embodiment, PON protection with improved fault tolerance is possible even in an OLT with a remote configuration used in rural areas. Therefore, when a fault occurs in an OLT, the workload of field workers who deal with the fault can be reduced.

[0015] FIG. 1 is a diagram showing an example of the configuration of a terminal device 1 of this embodiment. The terminal device 1 is an OLT with a remote configuration. The terminal device 1 has a master station 100, an optical selector 200, and a slave station 300. The master station 100 may be provided with the optical selector 200. The master station 100 and the optical selector 200 are examples of a first communication device, and the slave station 300 is an example of a second communication device. The slave station 300 may be connected to a lower slave station 300. The terminal device 1 is connected to a monitoring and control system 5. The monitoring and control system 5 monitors and controls the terminal device 1. In FIG. 1, solid lines between functional units represent main signal lines, and dashed lines between functional units represent control lines. The same applies to FIGS. 2 to 4, 6, and 7, which will be described later.

[0016] The master station 100 is connected to a lower-level device 7-1 via an optical transmission path 6-1, and the slave station 300 is connected to a lower-level device 7-2 via an optical transmission path 6-2. The lower-level devices 7-1 and 7-2 are collectively referred to as lower-level devices 7. The lower-level devices 7 are, for example, ONUs. The master station 100 is also connected to a higher-level device 8. The terminal device 1 converts optical signals transmitted from the lower-level device 7 into electrical signals and forwards them to the higher-level device 8, and converts electrical signals transmitted from the higher-level device 8 into optical signals and forwards them to the lower-level device 7. The direction from the lower-level device 7 to the higher-level device 8 is referred to as upstream, and the direction from the higher-level device 8 to the lower-level device 7 is referred to as downstream.

[0017] The master station 100 is equipped with a control PKG 110, a PON-PKG 120, a redundancy PKG 130, and a transfer PKG 140. The slave station 300 is equipped with a control PKG 310, a PON-PKG 320, a redundancy PKG 330, and a transfer PKG 340. During normal operation, the lower-level device 7-1 is connected to the PON-PKG 120 of the master station 100, and the lower-level device 7-2 is connected to the PON-PKG 320 of the slave station 300. The transfer PKG 140 and the transfer PKG 340 transfer main signals between the lower-level device 7-2 and the upper-level device 8 via a main signal line 250. The main signal line 250 is, for example, an optical transmission path such as an optical fiber.

[0018] The control PKG 110 of the master station 100 performs PON protection processing to switch the connection destination of the lower device 7-1 to the redundant PKG 130 when a malfunction occurs in the PON-PKG 120. Similarly, the control PKG 310 of the slave station 300 performs PON protection processing to switch the connection destination of the lower device 7-2 to the redundant PKG 330 when a malfunction occurs in the PON-PKG 320.

[0019] The transfer PKG 140 has a control unit 141, and the transfer PKG 340 has a control unit 341. When an abnormality occurs in the control PKG 110 of the master station 100, the command system of the master station 100 switches to the control unit 141 of the transfer PKG 140 and the control PKG 310 of the slave station 300. The transfer PKG 140 transmits and receives control signals to and from the control PKG 310 of the slave station 300, thereby achieving PON protection in the master station 100. Similarly, when an abnormality occurs in the control PKG 310 of the slave station 300, the command system of the slave station 300 switches to the control unit 341 of the transfer PKG 340 and the control PKG 110 of the master station 100. The transfer PKG 340 transmits and receives control signals to and from the control PKG 110 of the master station 100, thereby achieving PON protection in the slave station 300. The main signal line 250 is used to transmit the control signal, just as is the case for transmitting a main signal between the master station 100 and the slave station 300. It should be noted that a control line different from the main signal line 250 may be used to transmit the control signal.

[0020] The master station 100 may be connected to a plurality of slave stations 300. For example, the master station 100 may include a plurality of transfer PKGs 140, each connected to a different slave station 300. A slave station 300 may be connected to another slave station 300. When the terminal device 1 includes a plurality of slave stations 300, the master station 100 may not include the PON-PKG 120 and the redundant PKG 130.

[0021] FIG. 2 is a diagram showing an example of the configuration of the master station 100 and the optical selector 200. The master station 100 includes a control PKG 110, N (N is an integer equal to or greater than 1) PON-PKGs 120, M (M is an integer equal to or greater than 1) redundant PKGs 130, a transfer PKG 140, and a switch (SW) 150. The N PON-PKGs 120 are referred to as PON-PKGs 120-1 to 120-N. FIG. 2 shows an example where M=1. The control PKG 110 and the transfer PKG 140 are connected to the PON-PKGs 120, the redundant PKGs 130, and the optical selector 200 by control lines. The master station 100 and the slave stations 300 are connected by a main signal line 250 via the optical selector 200. In a normal state, the PON-PKG 120 is the active PKG, and the redundant PKG 130 is the standby PKG.

[0022] The control PKG 110 is a control panel. The control PKG 110 is equipped with a control unit 111. The control unit 111 controls each unit in the master station 100. The control unit 111 also monitors the status of each PKG of the master station. If the control unit 111 detects an abnormality in a PKG, it notifies the monitoring and control system 5 and performs PON protection. For example, if the control unit 111 detects an abnormality in a PON-PKG 120-n (n is an integer between 1 and N), it performs control to switch the connection destination of the lower-level device 7-1 connected to the PON-PKG 120-n to the redundant PKG 130. If the control unit 111 is notified by the slave station 300 of an abnormality in the control unit 311 of the slave station 300 and an abnormality in the PON-PKG 320, the control unit 111 performs PON protection for the slave station 300 that sent the notification.

[0023] The PON-PKG 120 terminates optical signals between the lower device 7-1. For example, the PON-PKG 120 is equipped with a PON interface of an OSU. The PON-PKG 120 converts upstream optical signals received from the lower device 7-1 via the optical transmission path 6-1 into electrical signals and outputs the signals to the SW 150. The PON-PKG 120 also converts downstream electrical signals received from the upper device 8 via the SW 150 into optical signals and transmits the optical signals to the lower device 7-1 via the optical transmission path 6-1.

[0024] The redundant PKG 130 has the same functions as the PON-PKG 120. For example, the redundant PKG 130 is equipped with an OSU PON interface. In a normal state where no abnormality occurs in any of the PON-PKGs 120, the redundant PKG 130 is not connected to the lower-level device 7-1. If an abnormality is detected in the PON-PKG 120-n, the redundant PKG 130 terminates the optical signal between the lower-level device 7-1 and the redundant PKG 130 instead of the PON-PKG 120-n.

[0025] The transfer PKG 140 connects its own station with other stations. The transfer PKG 140 includes a control unit 141 and a transfer processing unit 142. The control unit 141 is independent of the control unit 111 in the control PKG 110. The control unit 141 monitors the status of the control unit 111 in its own station. If the control unit 141 detects an abnormality in the control unit 111 in the control PKG 110, it switches the chain of command from the control unit 111 to the control unit 141 and transmits a notification to the slave station 300 via the main signal line 250 that the chain of command has been switched to the control unit 141. The notification that the chain of command has been switched to the control unit 141 corresponds to a notification that an abnormality in the control unit 111 has been detected. If the control unit 141 detects an abnormality in the operating PKG in the master station 100 while an abnormality is occurring in the control unit 111, it notifies the slave station 300 via the main signal line 250 that an abnormality in the operating PKG of the master station 100 has been detected. The control unit 141 outputs a control signal related to PON protection transmitted from the slave station 300 in response to this notification to the PON-PKG 120, the redundant PKG 130, and the optical selector 200. Furthermore, when the control unit 141 detects that the control unit 111 has recovered from the abnormal state, the control unit 141 transmits a notification to the slave station 300 via the main signal line 250 that the recovery of the control unit 111 has been detected.

[0026] The transfer processing unit 142 receives an upstream optical signal output by the slave station 300 from the optical selector 200, converts the received optical signal into an electrical signal, and outputs the electrical signal to the SW 150. The transfer processing unit 142 also converts a downstream electrical signal input from the SW 150 into an optical signal, and outputs the optical signal to the optical selector 200. The transfer processing unit 142 also transmits and receives control signals between the master station 100 and the slave station 300.

[0027] The SW150 is connected to the PON-PKG 120, the redundant PKG 130, the transfer PKG 140, and the higher-level device 8. The SW150 outputs upstream electrical signals input from the PON-PKG 120, the redundant PKG 130, and the transfer PKG 140 to the higher-level device 8. The SW150 also distributes downstream electrical signals received from the higher-level device 8 to the PON-PKG 120, the redundant PKG 130, and the transfer PKG 140 according to the destination, and outputs the signals.

[0028] The optical selector 200 includes a control unit 201 and an optical SW 210. The control unit 201 sets the line in the optical SW 210. The optical SW 210 has a plurality of first ports and a plurality of second ports (not shown). The main signal line 250 and the optical transmission path 6-1 are each connected to the first port. The PON-PKG 120, the redundant PKG 130, and the transfer PKG 140 are each connected to the second port. The optical SW 210 outputs an upstream optical signal input from the first port to the second port and outputs a downstream optical signal input from the second port to the first port in accordance with the correspondence between the first port and the second port indicated by the line set by the control unit 201.

[0029] The optical selector 200 may include a 2×2 coupler corresponding to each PON-PKG 120. The 2×2 coupler has two ports on each side, one on the primary side and one on the secondary side. A signal input to the primary side is output from each of the two ports on the secondary side, and a signal input to the secondary side is output from each of the two ports on the primary side. The first port on the secondary side of the 2×2 coupler is connected to the PON-PKG 120, and a lower-level device 7-1 is connected to the first port on the primary side, so that the PON-PKG 120 can be connected to the lower-level device 7-1 without using the optical SW 210. Another lower-level device 7-1 may be connected to the second port on the primary side of the 2×2 coupler. The second ports on the secondary sides of each 2×2 coupler are all connected to the first port of the optical SW 210. The redundant PKG 130 is then connected to the second port of the optical SW 210. This configuration enables communication without using the optical SW 210 during normal operation when the redundant PKG 130 is not operating.

[0030] FIG. 3 is a diagram showing an example of the configuration of a slave station 300. The slave station 300 has a control PKG 310, P (P is an integer equal to or greater than 1) PON-PKGs 320, Q (Q is an integer equal to or greater than 1) redundancy PKGs 330, a transfer PKG 340, and an optical selector 400. The P PON-PKGs 320 are referred to as PON-PKGs 320-1 to 320-P. FIG. 3 also shows an example where Q=1. The control PKG 310 and the transfer PKG 340 are connected to the PON-PKG 320, the redundancy PKG 330, and the optical selector 400 via control lines. In a normal state, the PON-PKG 320 is an active PKG, and the redundancy PKG 330 is a standby PKG.

[0031] The control PKG 310 is a control panel. The control PKG 310 is equipped with a control unit 311. The control unit 311 controls each unit in the slave station 300. The control unit 311 also monitors the status of each PKG of the slave station 300. If the control unit 311 detects an abnormality in a PKG, it notifies the monitoring and control system 5 and performs PON protection. For example, if the control unit 311 detects an abnormality in a PON-PKG 320-p (p is an integer between 1 and P), it performs control to switch the connection destination of the lower-level device 7-2 connected to the PON-PKG 320-p to the redundant PKG 330. If the control unit 311 is notified by the master station 100 of an abnormality in the control unit 111 of the master station 100 and an abnormality in the PON-PKG 120, the control unit 311 performs PON protection for the master station 100.

[0032] The PON-PKG 320 terminates optical signals between the lower device 7-2. For example, the PON-PKG 320 is equipped with a PON interface of an OSU. The PON-PKG 320 may have the same functions as the PON-PKG 120 of the master station 100. The PON-PKG 320 converts upstream optical signals received from the lower device 7-2 via the optical transmission path 6-2 into electrical signals and outputs the signals to the transfer PKG 340. The PON-PKG 320 also converts downstream electrical signals input from the transfer PKG 340 into optical signals and transmits the optical signals to the lower device 7-2 via the optical transmission path 6-2.

[0033] The redundant PKG 330 has the same functions as the PON-PKG 320. For example, the redundant PKG 330 is equipped with an OSU PON interface. In a normal state where no abnormality occurs in any of the PON-PKGs 320, the redundant PKG 330 is not connected to the lower-level device 7-2. If an abnormality is detected in the PON-PKG 320-p, the redundant PKG 330 terminates the optical signal between the lower-level device 7-2 in place of the PON-PKG 320-p.

[0034] The transfer PKG 340 connects its own station with other stations. The transfer PKG 340 includes a control unit 341 and a transfer processing unit 342. The control unit 341 is independent of the control unit 311 in the control PKG 310. The control unit 341 monitors the status of the control unit 311 in its own station. If the control unit 341 detects an abnormality in the control unit 311 in the control PKG 310, it switches the chain of command from the control unit 311 to the control unit 341 and transmits a notification to the master station 100 via the main signal line 250 that the chain of command has been switched to the control unit 311. The notification that the chain of command has been switched to the control unit 311 corresponds to a notification that an abnormality in the control unit 311 has been detected. If the control unit 341 detects an abnormality in the operating PKG in the slave station 300 while an abnormality is occurring in the control unit 311, it notifies the master station 100 via the main signal line 250 that an abnormality in the operating PKG of the slave station 300 has been detected. The control unit 341 outputs a control signal related to PON protection transmitted from the master station 100 in response to this notification to the PON-PKG 320, the redundant PKG 330, and the optical selector 400. Furthermore, when the control unit 341 detects that the control unit 311 has recovered from the abnormal state, the control unit 341 transmits a notification to the master station 100 via the main signal line 250 that the recovery of the control unit 311 has been detected.

[0035] The transfer processing unit 342 receives upstream electrical signals from the PON-PKG 320 and the redundant PKG 330, converts the received electrical signals into optical signals, and outputs the optical signals to the transfer PKG 340. The transfer processing unit 342 also converts downstream electrical signals received from the main signal line 250 into optical signals and outputs the optical signals to the optical selector 400. The transfer processing unit 342 also transmits and receives control signals between the slave stations 300 and the master station 100.

[0036] The optical selector 400 includes a control unit 401 and an optical SW 410. The control unit 401 sets a line in the optical SW 410. The optical SW 410 has a plurality of first ports and a plurality of second ports (not shown). The optical transmission lines 6-2 are each connected to the first port. The PON-PKG 320 and the redundant PKG 330 are each connected to the second port. The optical SW 410 outputs an upstream optical signal input from the first port to the second port and outputs a downstream optical signal input from the second port to the first port in accordance with the correspondence between the first port and the second port indicated by the line set by the control unit 401.

[0037] The optical selector 400 may include a 2×2 coupler corresponding to each PON-PKG 320. The first port on the secondary side of the 2×2 coupler is connected to the PON-PKG 320, and the lower-level device 7-2 is connected to the first port on the primary side, so that the PON-PKG 320 may be connected to the lower-level device 7-2 without going through the optical SW 410. Another lower-level device 7-2 may be connected to the second port on the primary side of the 2×2 coupler. The second ports on the secondary sides of all 2×2 couplers are connected to the first port of the optical SW 410. The redundant PKG 330 is then connected to the second port of the optical SW 410. With this configuration, communication is possible without using the optical SW 410 during normal operation when the redundant PKG 330 is not operating.

[0038] FIG. 4 is a block diagram showing functions related to PON protection in the master station 100 and the slave station 300. The communication station 10 corresponds to the master station 100 and the slave station 300. The communication station 10 has a control unit 11, an operation PKG 12, a backup PKG 13, and a transfer PKG 14. The transfer PKG 14 has a control unit 15. The control unit 11 corresponds to the control unit 111 and the control unit 311, the operation PKG 12 corresponds to the PON-PKG 120 and the PON-PKG 320, the backup PKG 13 corresponds to the redundancy PKG 130 and the redundancy PKG 330, the transfer PKG 14 corresponds to the transfer PKG 140 and the transfer PKG 340, and the control unit 15 corresponds to the control unit 141 and the control unit 341. The communication station 10 is connected to another station or a lower-level device 7 via an optical selector unit 20. The optical selector unit 20 corresponds to the optical selector 200 and the optical selector 400.

[0039] The control unit 11 controls the entire communication station 10. When the control unit 11 detects an abnormality in the PKG of its own device, it notifies the monitoring and control system 5 and performs PON protection. For example, when the control unit 11 detects an abnormality in the operating PKG 12, it controls the connection of the lower-level device 7 connected to the operating PKG 12 to be switched to the backup PKG 13. Furthermore, when the control unit 11 is notified of an abnormality in the control unit 11 of another station and an abnormality in the backup PKG 13, it performs PON protection for the other station that sent the notification via the main signal line and the control unit 15 provided in the transfer PKG 14.

[0040] The operation PKG 12 terminates optical signals between the operation PKG 12 and the lower-level device 7. The backup PKG 13 has the same functions as the operation PKG 12, but is not connected to the lower-level device 7 in the normal state.

[0041] The transfer PKG 14 connects the local station with other stations. The transfer PKG 14 relays main signals whose source or destination is a subordinate device 7 under the control of another communication device. The control unit 15 provided in the transfer PKG 14 is independent of the control unit 11. If the control unit 15 detects an abnormality in the control unit 11 of the local station, it switches the chain of command from the control unit 11 to the control unit 15 and transmits a notification of the command switch to the other station via the main signal line. If the control unit 15 detects an abnormality in the operating PKG 12 of the local device while an abnormality is occurring in the control unit 11, it notifies the other station via the main signal line that it has detected an abnormality in the operating PKG. The control unit 15 executes PON protection for the local station based on a control signal related to PON protection transmitted from the other station in response to this notification.

[0042] 5 is a flow diagram showing the processing of the terminal device 1. After the master station 100 is started up, the control unit 141 of the transfer PKG 140 starts monitoring the control unit 111 of the control PKG 110. After the slave station 300 is started up, the control unit 341 of the transfer PKG 340 starts monitoring the control unit 311 of the control PKG 310.

[0043] In the master station 100, the control unit 141 of the transfer PKG 140 determines whether or not an abnormality has been detected in the control unit 111 mounted on the control PKG 110 (step S1). If the control unit 141 of the transfer PKG 140 detects an abnormality in the control unit 111 (step S1: YES), it switches the chain of command from the control unit 111 to the control unit 141 (step S2). The control unit 141 of the transfer PKG 140 notifies the slave station 300 that the chain of command has been switched to the slave station 300 by transmitting a chain of command switching notification to the slave station 300 (step S3). That is, the control unit 141 outputs the chain of command switching notification to the transfer processing unit 142. The transfer processing unit 142 outputs the chain of command switching notification to the optical selector 200 by a downstream optical signal. The optical selector 200 outputs the chain of command switching notification input from the transfer PKG 140 of the master station 100 to the main signal line 250. Transmission of control signals such as notifications between the master station 100 and the slave station 300 is performed in-channel between the transfer PKG 140 and the transfer PKG 340, using a control VLAN (Virtual Local Area Network) or the like.

[0044] The transfer processing unit 342 included in the transfer PKG 340 of the slave station 300 receives an optical signal from the master station 100. The control unit 311 of the control PKG 310 acquires a command system switching notification from the optical signal received by the transfer PKG 340. The control unit 311 of the control PKG 310 notifies the monitoring control system 5 that the command system of the master station 100 has been switched to the slave station 300 (step S4). This notification corresponds to a notification of an abnormality in the control unit 111 in the control PKG 110 included in the master station 100.

[0045] In the master station 100, the control unit 141 of the transfer PKG 140 determines whether or not recovery of the control unit 111 mounted on the control PKG 110 has been detected (step S5). If the control unit 141 of the transfer PKG 140 does not detect recovery (step S5: NO), it repeats the processing of step S5.

[0046] When the control unit 141 of the transfer PKG 140 detects the recovery of the control unit 111 (step S5: YES), it transmits a recovery notification to the slave station 300 to notify the slave station 300 that the control unit 111 of the master station 100 has recovered. The recovery notification is transmitted by the same process as the transmission of the command system switching notification in step S3. The control unit 141 of the transfer PKG 140 switches the command system back to the control unit 111 of the master station 100 (step S6). When the control unit 311 in the control PKG 310 of the slave station 300 acquires the recovery notification from the optical signal received by the transfer PKG 340, it returns the command system of the master station 100 to the master station 100. The control unit 111 in the control PKG 110 of the master station 100 notifies the monitoring control system 5 that the command system has been restored (step S7). This notification corresponds to a notification that the control unit 111 of the master station 100 has recovered from the failure. The terminal device 1 repeats the process from step S1.

[0047] In the master station 100, if the control unit 141 of the transfer PKG 140 has not detected an abnormality in the control unit 111 mounted on the control PKG 110 (step S1: NO), in the slave station 300, the control unit 341 of the transfer PKG 340 determines whether or not an abnormality in the control unit 311 mounted on the control PKG 310 has been detected (step S8). If the control unit 341 of the transfer PKG 340 has not detected an abnormality in the control unit 311 (step S8: NO), the terminal device 1 repeats the processing from step S1.

[0048] On the other hand, if the control unit 341 of the transfer PKG 340 detects an abnormality in the control unit 311 (step S8: YES), it switches the chain of command from the control unit 311 to the control unit 341 (step S9). The control unit 341 of the transfer PKG 340 notifies the master station 100 that the chain of command has been switched to the master station 100 by transmitting a chain of command switching notification to the master station 100 (step S10). That is, the control unit 341 outputs the chain of command switching notification to the transfer processing unit 342. The transfer processing unit 342 transmits the chain of command switching notification to the master station 100 by an upstream optical signal. Note that this transmission is performed in-channel between the transfer PKG 140 and the transfer PKG 340, and a control VLAN or the like is used.

[0049] The optical selector 200 receives an optical signal transmitted from the slave station 300 and outputs it to the transfer PKG 140 of the master station 100. The transfer processing unit 142 included in the transfer PKG 140 of the master station 100 receives the optical signal from the optical selector 200. The control unit 111 of the control PKG 110 acquires a command system switching notification from the optical signal received by the transfer PKG 140. The control unit 111 of the control PKG 110 notifies the monitoring control system 5 that the command system of the slave station 300 has been switched to the master station 100 (step S11). This notification corresponds to a notification of an abnormality in the control unit 311 in the control PKG 310 of the slave station 300.

[0050] In the slave station 300, the control unit 341 of the transfer PKG 340 determines whether or not recovery of the control unit 311 mounted on the control PKG 310 has been detected (step S12). If the control unit 341 of the transfer PKG 340 does not detect recovery (step S12: NO), it repeats the processing of step S12.

[0051] When the control unit 341 of the transfer PKG 340 detects the recovery of the control unit 311 (step S12: YES), it transmits a recovery notification to the master station 100 to notify the master station 100 that the control unit 311 of the slave station 300 has recovered. The recovery notification is transmitted by the same process as the transmission of the command system switching notification in step S10. The control unit 341 of the transfer PKG 340 switches the command system back to the control unit 311 of the slave station 300 (step S13). When the control unit 111 in the control PKG 110 possessed by the master station 100 acquires the recovery notification from the optical signal received by the transfer PKG 140, it returns the command system of the slave station 300 to the slave station 300. The control unit 311 in the control PKG 310 possessed by the slave station 300 notifies the monitoring and control system 5 that the command system has been restored (step S14). This notification corresponds to a notification that the control unit 311 of the slave station 300 has recovered from the failure. The terminal device 1 repeats the process from step S1.

[0052] Next, the operation of PON protection in the terminal device 1 will be described. Fig. 6 is a diagram showing an example of the operation of PON protection in the terminal device 1. Fig. 6 shows the operation of PON protection when an abnormality occurs in the control PKG 110 and PON-PKG 120 of the master station 100. Before explaining Fig. 6, we will first explain the operation when an abnormality occurs in the PON-PKG 120 of the master station 100 when the control PKG 110 of the master station 100 is normal and PON protection is performed.

[0053] First, the relay processing of the terminal device 1 under normal circumstances when no abnormality occurs in the PON-PKG 120 will be described using as an example the lower device 7a, which is the lower device 7-1 connected to the PON-PKG 120-1.

[0054] The optical SW210 of the optical selector 200 receives an upstream optical signal transmitted from the lower-level device 7a via the optical transmission path 6-1, and outputs the signal to the PON-PKG 120-1, which is the output destination corresponding to the first port through which the optical signal was received. The PON-PKG 120-1 converts the received optical signal into an electrical signal and outputs it to the SW150. The SW150 transfers the upstream electrical signal received from the PON-PKG 120-1 to the upper-level device 8.

[0055] Furthermore, the upper device 8 transmits a downstream signal addressed to the lower device 7a. The SW150 outputs the downstream signal to the PON-PKG 120-1 according to the destination. The PON-PKG 120-1 converts the electrical optical signal into an optical signal and outputs it to the optical selector 200. The optical SW210 of the optical selector 200 inputs the optical signal from the PON-PKG 120-1 and outputs it to the optical transmission path 6-1, which is the output destination according to the second port from which the optical signal was input. The lower device 7a receives the optical signal transmitted through the optical transmission path 6-1.

[0056] When the optical selector 200 is equipped with a 2x2 coupler corresponding to each PON-PKG 120, the 2x2 coupler of the optical selector 200 inputs the upstream optical signal transmitted by the lower-level device 7a from the optical transmission path 6-1 and outputs it to the PON-PKG 120-1, and outputs the downstream optical signal transmitted from the PON-PKG 120-1 to the optical transmission path 6-1 and transmits it to the lower-level device 7a.

[0057] When the control unit 111 of the control PKG 110 detects an abnormality in the PON-PKG 120-1, it performs PON protection processing. The control unit 111 instructs the redundant PKG 130 to take over the settings of the PON-PKG 120-1. Furthermore, the control unit 111 instructs the control unit 201 of the optical selector 200 to change the line so that the second port connected to the redundant PKG 130 is used instead of the second port of the optical SW 210 connected to the PON-PKG 120-1. Furthermore, the control unit 111 instructs the SW 150 to change the line so that the SW 150 is connected to the redundant PKG 130 instead of the PON-PKG 120-1.

[0058] When the optical selector 200 is equipped with a 2x2 coupler corresponding to each PON-PKG 120, the control unit 111 instructs the control unit 201 of the optical selector 200 to set up in the optical SW 210 a line between the first port connected to the 2x2 coupler corresponding to the PON-PKG 120-1 and the second port connected to the redundant PKG 130.

[0059] After the PON protection process, the parent station 100 of the terminal device 1 performs relay processing as follows. That is, the optical SW210 of the optical selector 200 receives the optical signal transmitted from the lower-level device 7a via the optical transmission path 6-1 and outputs it to the redundant PKG 130, which is the output destination corresponding to the first port through which the optical signal was received. The redundant PKG 130 converts the received optical signal into an electrical signal and outputs it to the SW150. The SW150 transfers the upstream electrical signal received from the redundant PKG 130 to the upper-level device 8.

[0060] Furthermore, the upper device 8 transmits a downstream signal addressed to the lower device 7a. The SW150 outputs the downstream signal to the redundant PKG 130 according to the destination. The redundant PKG 130 converts the electrical optical signal into an optical signal and outputs it to the optical selector 200. The optical SW210 of the optical selector 200 inputs the optical signal from the redundant PKG 130 and outputs it to the optical transmission path 6-1, which is the output destination according to the second port from which the optical signal was input. The lower device 7a receives the optical signal transmitted through the optical transmission path 6-1.

[0061] In addition, if the PON protection setting set in the parent station 100 and the monitoring control system 5 is manual, the control unit 111 in the control PKG 110 of the parent station 100, which receives instructions from the monitoring control system 5 through operator operation, performs the above-mentioned PON protection processing.

[0062] Next, with reference to FIG. 6, an operation will be described in which an abnormality occurs in the control PKG 110 of the master station 100, control of the master station 100 is switched to the slave station 300, and then an abnormality occurs in the PON-PKG 120-1 of the master station 100, causing PON protection.

[0063] The terminal device 1 is performing the relay processing before the abnormality occurred in the PON-PKG 120 described above. When an abnormality occurs in the control PKG 110 of the master station 100, the control unit 141 of the transfer PKG 140 detects it (step S21). The control unit 141 switches the chain of command from the control unit 111 of the control PKG 110 to the control unit 141 (step S22). The control unit 141 transmits a chain of command switching notification to the slave station 300 (step S23). Upon receiving the chain of command switching notification, the control unit 311 of the control PKG 310 included in the slave station 300 starts controlling the master station 100. The control unit 311 of the control PKG 310 notifies the monitoring and control system 5 that the chain of command of the master station 100 has been shifted to the slave station 300 (step S24).

[0064] Next, the control unit 141 in the transfer PKG 140 of the master station 100 detects an abnormality in the PON-PKG 120-1 (step S25). The control unit 141 transmits a PKG abnormality detection notification to the slave station 300 notifying that an abnormality in the PON-PKG 120-1 has been detected (step S26). If the PON protection setting is automatic, the control unit 311 of the control PKG 310 included in the slave station 300 performs the same processing as the control unit 111 of the master station 100 described above, and switches the PON-PKG 120-1 of the master station 100 to the redundant PKG 130.

[0065] That is, the control unit 311 instructs the redundant PKG 130 to take over the settings of the PON-PKG 120-1. Furthermore, the control unit 311 instructs the control unit 201 of the optical selector 200 to change the line so that the second port connected to the redundant PKG 130 is used instead of the second port of the optical SW 210 connected to the PON-PKG 120-1. Furthermore, the control unit 311 instructs the SW 150 to change the line so that the connection with the PON-PKG 120-1 is changed to a connection with the redundant PKG 130. Note that these instructions from the control unit 311 are transmitted from the transfer PKG 340 to the transfer PKG 140 by optical signals. The control unit 141 of the transfer PKG 140 acquires these instructions and outputs them to each unit.

[0066] When the optical selector 200 is equipped with a 2x2 coupler corresponding to each PON-PKG 120, the control unit 311 instructs the control unit 201 of the optical selector 200 to set up in the optical SW 210 a line between the first port connected to the 2x2 coupler corresponding to the PON-PKG 120-1 and the second port connected to the redundant PKG 130.

[0067] As a result, the master station 100 of the terminal device 1 performs the relay process after the PON protection process described above.

[0068] In addition, if the PON protection setting in the slave station 300 and the monitoring control system 5 is manual, the control unit 311 of the slave station 300, which receives instructions from the monitoring control system 5 through operator operation, performs the above-mentioned PON protection processing.

[0069] Fig. 7 is a diagram showing an example of the PON protection operation of the terminal device 1 when an abnormality occurs in the control PKG 310 and PON-PKG 320 of the slave station 300. Before explaining Fig. 7, we will explain the operation when an abnormality occurs in the PON-PKG 320 of the slave station 300 and PON protection is performed when the control PKG 310 of the slave station 300 is normal.

[0070] First, the relay processing of the terminal device 1 under normal conditions when no abnormality occurs in the PON-PKG 320 will be described using the example of the lower device 7b, which is the lower device 7-2 connected to the PON-PKG 320-1. The optical SW 410 of the optical selector 400 receives an upstream optical signal transmitted from the lower device 7b via the optical transmission path 6-2 and outputs it to the PON-PKG 320-1, which is the output destination corresponding to the first port through which the optical signal was received. The PON-PKG 320-1 converts the received optical signal into an electrical signal and outputs it to the transfer PKG 340. The transfer PKG 340 converts the electrical signal output from the PON-PKG 320 into an optical signal and transmits the optical signal to the master station 100 via the main signal line 250. The optical SW 210 of the optical selector 200 outputs the optical signal received from the main signal line 250 to the transfer PKG 140 of the master station 100. The transfer PKG 140 converts the input upstream signal into an electrical signal and outputs it to the SW 150. The SW 150 transfers the upstream electrical signal to the upper device 8.

[0071] Furthermore, the upper device 8 transmits a downstream signal addressed to the lower device 7b. The SW150 outputs the downstream signal to the transfer PKG 140 according to the destination. The transfer PKG 140 converts the electrical optical signal into an optical signal and outputs it to the optical selector 200. The optical SW210 of the optical selector 200 transmits the optical signal input from the transfer PKG 140 to the slave station 300 via the main signal line 250. The transfer processing unit 342 of the transfer PKG 340 provided in the slave station 300 converts the downstream optical signal transmitted through the main signal line 250 into an electrical signal and outputs it to the PON-PKG 320-1 according to the destination. The PON-PKG 320-1 converts the input electrical signal into an optical signal and outputs it to the optical selector 400. The optical SW410 of the optical selector 400 inputs the optical signal from the PON-PKG 320-1 and outputs it to the optical transmission path 6-2, the output destination according to the second port from which the optical signal was input. The lower-level device 7b receives the optical signal transmitted through the optical transmission line 6-2.

[0072] When the optical selector 400 is equipped with a 2x2 coupler corresponding to each PON-PKG 320, the 2x2 coupler of the optical selector 400 inputs the upstream optical signal transmitted by the lower-level device 7b from the optical transmission path 6-2 and outputs it to the PON-PKG 320-1, and outputs the downstream optical signal transmitted from the PON-PKG 320-1 to the optical transmission path 6-2 and transmits it to the lower-level device 7b.

[0073] When the control unit 311 of the control PKG 310 detects an abnormality in the PON-PKG 320-1, it performs PON protection processing. The control unit 311 instructs the redundant PKG 330 to take over the settings of the PON-PKG 320-1. Furthermore, the control unit 311 instructs the control unit 401 of the optical selector 400 to change the line so that the second port connected to the redundant PKG 330 is used instead of the second port connected to the PON-PKG 320-1. Furthermore, the control unit 311 instructs the transfer PKG 340 to change the input / output destination of the optical signal so that the transfer PKG 340 is connected to the redundant PKG 330 instead of the PON-PKG 320-1.

[0074] When the optical selector 400 is equipped with a 2x2 coupler corresponding to each PON-PKG320, the control unit 311 instructs the control unit 401 of the optical selector 400 to set up in the optical SW410 a line between the first port connected to the 2x2 coupler corresponding to the PON-PKG320-1 and the second port connected to the redundant PKG330.

[0075] After the PON protection process, the master station 100 of the terminal device 1 performs relay processing as follows. That is, the optical SW 410 of the optical selector 400 receives an optical signal transmitted from the lower device 7b via the optical transmission path 6-2, and outputs the optical signal to the redundant PKG 330, which is the output destination corresponding to the first port through which the optical signal was received. The redundant PKG 330 converts the received optical signal into an electrical signal and outputs it to the transfer PKG 340. The transfer PKG 340 converts the electrical signals received from the PON-PKGs 320-2 to 320-P and the redundant PKG 330 into optical signals, and transmits them to the slave station 300 via the main signal line 250. The optical selector 200 and the master station 100 operate in the same manner as described above.

[0076] Furthermore, when the master station 100 receives a downstream signal addressed to the lower device 7b from the upper device 8, the master station 100 and the optical selector 200 operate in the same manner as described above. The transfer processing unit 342 of the transfer PKG 340 provided in the slave station 300 converts the downstream optical signal transmitted on the main signal line 250 into an electrical signal and outputs it to the redundant PKG 330 corresponding to the destination. The redundant PKG 330 converts the input electrical signal into an optical signal and outputs it to the optical selector 400. The optical SW 410 of the optical selector 400 inputs the optical signal from the redundant PKG 330 and outputs it to the optical transmission path 6-2, which is the output destination corresponding to the second port through which the optical signal was input. The lower device 7b receives the optical signal transmitted on the optical transmission path 6-2.

[0077] In addition, if the PON protection setting set in the slave station 300 and the monitoring control system 5 is manual, the control unit 311 in the control PKG 310 of the slave station 300, which receives instructions from the monitoring control system 5 through operator operation, performs the above-mentioned PON protection processing.

[0078] Next, with reference to FIG. 7, an operation will be described in which an abnormality occurs in the control PKG 310 of the slave station 300, control of the slave station 300 is switched to the master station 100, and then an abnormality occurs in the PON-PKG 320 of the slave station 300, causing PON protection.

[0079] The terminal device 1 is performing the relay processing before the abnormality occurred in the PON-PKG 320 described above. When an abnormality occurs in the control PKG 310 of the slave station 300, the control unit 341 of the transfer PKG 340 detects it (step S31). The control unit 341 switches the chain of command from the control unit 311 of the control PKG 310 to the control unit 341 (step S32). The control unit 341 transmits a chain of command switching notification to the master station 100 (step S33). Upon receiving the chain of command switching notification, the control unit 111 of the control PKG 110 provided in the master station 100 starts controlling the slave station 300. The control unit 111 of the control PKG 110 notifies the monitoring and control system 5 that the chain of command of the slave station 300 has been shifted to the master station 100 (step S34).

[0080] Next, the control unit 341 in the transfer PKG 340 of the slave station 300 detects an abnormality in the PON-PKG 320-1 (step S35). The control unit 341 transmits a PKG abnormality detection notification to the master station 100 notifying that an abnormality in the PON-PKG 320-1 has been detected (step S36). When the PON protection setting is automatic, the control unit 111 of the control PKG 110 provided in the master station 100 performs the same processing as the control unit 311 of the slave station 300 described above, and switches the PON-PKG 320-1 of the slave station 300 to the redundant PKG 330.

[0081] That is, the control unit 111 instructs the redundant PKG 330 to take over the settings of the PON-PKG 320-1. Furthermore, the control unit 111 instructs the control unit 401 of the optical selector 400 to change the line so that the second port connected to the redundant PKG 330 is used instead of the second port of the optical SW 410 connected to the PON-PKG 320-1. Furthermore, the control unit 111 instructs the transfer PKG 340 to change the line so that the connection with the PON-PKG 320-1 is changed to a connection with the redundant PKG 330. Note that these instructions from the control unit 111 are transmitted from the transfer PKG 140 to the transfer PKG 340 by optical signals. The control unit 341 of the transfer PKG 340 acquires these instructions and outputs them to each unit.

[0082] When the optical selector 400 is equipped with a 2x2 coupler corresponding to each PON-PKG320, the control unit 111 instructs the control unit 401 of the optical selector 400 to set up in the optical SW410 a line between the first port connected to the 2x2 coupler corresponding to the PON-PKG320-1 and the second port connected to the redundant PKG330.

[0083] As a result, the slave station 300 of the terminal device 1 performs the relay process after the PON protection process described above.

[0084] In addition, if the PON protection settings set in the master station 100 and the monitoring control system 5 are manual, the control unit 111 of the master station 100, which receives instructions from the monitoring control system 5 through operator operation, performs the above-mentioned PON protection processing.

[0085] In the above, an example has been described in which the main signal and the control signal are transmitted and received between the master station 100 and the slave station 300 by optical signals, but this is not limiting and, for example, they may be transmitted and received by electrical signals. In this case, an electrical signal transfer device transfers the main signal and the control signal instead of the optical selector 200. The transfer device transfers the electrical main signal and the control signal between the master station 100 and the slave station 300 in the same way as the optical selector 200. The transfer processing unit 142 of the transfer PKG 140 and the transfer processing unit 342 of the PKG 340 transmit and receive the main signal and the control signal as electrical signals without converting them to optical signals.

[0086] In the above, the case where electrical signals are transmitted and received between the PON-PKG 120 and the redundant PKG 130 and the SW 150, and between the PON-PKG 320 and the redundant PKG 330 and the transfer PKG 340 has been described, but optical signals may also be transmitted and received. In this case, the transfer PKG 140 and the transfer PKG 340 transfer the optical signals without converting them into electrical signals.

[0087] In the above description, the lower-level devices 7-1 and 7-2 connected to the terminal device 1 transmit and receive optical signals, but this is not limiting. That is, the lower-level devices 7-1 and 7-2 may transmit and receive electrical signals, wireless signals, etc. In this case, instead of the PON-PKG 120, the redundant PKG 130, the PON-PKG 320, and the redundant PKG 330, a termination device that terminates signals between the lower-level devices is used. And instead of the optical selectors 200 and 400, a transfer device that transfers signals between the lower-level devices and the termination device is used. The signals between the termination device and the transfer PKG 140 and between the termination device and the SW 150 are, for example, electrical signals, but this is not limiting.

[0088] Although the above describes an example in which the host device 8 and the master station 100 transmit and receive electrical signals, the present invention is not limited to this. For example, the host device 8 and the master station 100 may transmit and receive optical signals. When the host device 8 and the master station 100 transmit and receive optical signals, the PON-PKG 120, the redundant PKG 130, and the transfer PKG 140 output upstream main signals to the SW 150 as optical signals and receive downstream main signals from the SW 150 as optical signals. The PON-PKG 120, the redundant PKG 130, and the transfer PKG 140 do not need to convert between optical signals and electrical signals. Alternatively, the SW 150 may transmit and receive optical signals to and from the optical selector 200 without going through the PON-PKG 120 and the redundant PKG 130.

[0089] The above-described control units 111, 131, 311, and 331 may each include a processor, memory, auxiliary storage device, and the like, all connected via a bus, and the processor may execute a program to realize the above functions. The processor may be, for example, a central processing unit (CPU) or a graphics processing unit (GPU). Note that all or part of the functions of the control units 111, 131, 311, and 331 may be realized using hardware such as an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a field-programmable gate array (FPGA). The programs for the control units 111, 131, 311, and 331 may be recorded on a computer-readable recording medium. Examples of computer-readable recording media include portable media such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and storage devices such as a hard disk built into a computer system. The programs for the control units 111, 131, 311, and 331 may be transmitted via a telecommunications line.

[0090] According to the above-described embodiment, the terminal device includes a first communication device and a second communication device. For example, the terminal device corresponds to the terminal device 1 of the embodiment, the first communication device corresponds to the master station 100 of the embodiment, and the second communication device corresponds to the slave station 300 of the embodiment.

[0091] The first communication device includes a redundant first terminal device, a first transceiver, a first control unit, and a first monitoring control unit. For example, the first terminal device corresponds to the PON-PKG 120 and the redundant PKG 130 of the embodiment, the first transceiver corresponds to the transfer PKG 140 of the embodiment, the first control unit corresponds to the control unit 111 of the embodiment, and the first monitoring control unit corresponds to the control unit 141 of the embodiment. The first terminal device terminates signals between the first lower device and the first lower device. The first lower device corresponds to, for example, the lower device 7-1 of the embodiment. The first transceiver transmits and receives main signals whose source or destination is the second lower device with the second communication device. The second lower device corresponds to, for example, the lower device 7-2 of the embodiment. When an abnormality occurs in the first terminal device currently in operation, the first control unit performs first switching control to switch the abnormal first terminal device to a spare first terminal device. The first monitoring control unit monitors the status of the first control unit.

[0092] The second communication device includes a redundant second termination device, a second transceiver, a second control unit, and a second monitoring and control unit. For example, the second termination device corresponds to the PON-PKG 320 and the redundant PKG 330 of the embodiment, the second transceiver corresponds to the transfer PKG 340 of the embodiment, the second control unit corresponds to the control unit 311 of the embodiment, and the second monitoring and control unit corresponds to the control unit 341 of the embodiment. The second termination device terminates signals between the second lower device and the second lower device. The second transceiver performs a process of transmitting a main signal received from the first transceiver to the second lower device via the second termination device and a process of transmitting a main signal received from the second lower device by the second termination device to the first communication device. When an abnormality occurs in the second termination device currently in operation, the second control unit performs second switching control to switch the second termination device in which the abnormality has occurred to a spare second termination device. The second monitoring and control unit monitors the status of the second control unit. The first control unit performs second switching control when the second monitoring and control unit notifies the first control unit of the occurrence of an abnormality in the second control unit and the occurrence of an abnormality in the second termination device currently in operation. The second control unit performs first switching control when notified by the first monitoring control unit that an abnormality has occurred in the first control unit and that an abnormality has occurred in the first terminal device during operation.

[0093] The second monitoring control unit may transmit a notification of an abnormality in the second control unit and a notification of an abnormality in the second terminating device during operation using a main signal line that transmits a main signal between the first transceiver unit and the second transceiver unit. The first monitoring control unit may transmit a notification of an abnormality in the first control unit and a notification of an abnormality in the first terminating device during operation using the main signal line.

[0094] The main signal line may be an optical transmission line, in which case the first transceiver and the second transceiver transmit an optical main signal.

[0095] The first control unit may perform a process of notifying an external system of the occurrence of an abnormality in the second control unit when the second monitoring control unit is notified of the occurrence of an abnormality in the second control unit, and a process of notifying the external system of the recovery of the first control unit when the first control unit has recovered from a failure.The second control unit may perform a process of notifying the external system of the occurrence of an abnormality in the first control unit when the first monitoring control unit is notified of the occurrence of an abnormality in the first control unit, and a process of notifying the external system of the recovery of the second control unit when the second control unit has recovered from a failure.The external system is, for example, the monitoring and control system of an embodiment.

[0096] The first transmitter / receiver and the first monitoring control unit may be mounted in the same package, and the second transmitter / receiver and the second monitoring control unit may be mounted in the same package.

[0097] The communication device also includes redundant terminating devices, a relay unit, a control unit, and a monitoring and control unit. For example, the terminating devices correspond to the operation PKG 12 and the backup PKG 13 of the embodiment, the relay unit corresponds to the relay PKG 14 of the embodiment, the control unit corresponds to the control unit 11 of the embodiment, and the management and control unit corresponds to the control unit 15 of the embodiment. The terminating devices terminate signals between lower-level devices. The relay unit relays main signals whose source or destination is a subordinate device under another communication device. When an abnormality occurs in an operating terminating device, the control unit performs switching control to switch the terminating device in which the abnormality has occurred to a backup terminating device. The monitoring and control unit outputs a notification when an abnormality occurs in the control unit and when an abnormality occurs in an operating terminating device. The communication device receives switching control from another communication device that has received a notification of the occurrence of the abnormality in the control unit and a notification of the occurrence of the abnormality in an operating terminating device.

[0098] The first termination device may terminate optical signals to and from a first lower-level device, and the second termination device may terminate optical signals to and from a second lower-level device.

[0099] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention. [Explanation of symbols]

[0100] 1 Terminal equipment 5. Monitoring and Control System 6-1, 6-2 Optical transmission line 7-1, 7-2, 7a, 7b Lower device 8 Upper device 10 Communications Bureau 11 Control section 12 Operational PKG 13 Spare PKG 14 Transfer PKG 15 Control Unit 100 Master station 110 Control Package 111 Control Unit 120, 120-1 to 120-N PON-PKG 130 Redundant PKG 140 Transfer PKG 141 Control Unit 142 Transfer Processing Unit 200 Optical Selector 201 Control Unit 210 Optical Switch 300 slave stations 310 Control Package 320, 320-1 to 320-P PON-PKG 330 Redundant PKG 340 Transfer PKG 400 Optical Selector 401 Control Unit 410 Optical SW

Claims

1. A terminal device including a first communication device and a second communication device, The first communication device a redundant first termination device that terminates signals between the first lower-level device and the first lower-level device; a first transceiver for transmitting and receiving a source or destination main signal from a second lower-level device to and from the second communication device; a first control unit that performs first switching control to switch the first terminal device in operation where an abnormality has occurred to a standby first terminal device when an abnormality has occurred in the first terminal device in operation; a first monitoring control unit that monitors a state of the first control unit; The second communication device a redundant second termination device that terminates signals between the second lower-level device and the second lower-level device; a second transceiver that performs a process of transmitting the main signal received from the first transceiver to the second lower-level device via the second terminal device, and a process of transmitting the main signal received by the second terminal device from the second lower-level device to the first communication device; a second control unit that performs second switching control to switch the second terminal device in operation where an abnormality occurs to a standby second terminal device when an abnormality occurs in the second terminal device in operation; a second monitoring control unit that monitors the state of the second control unit; the first control unit performs the second switching control when notified by the second monitoring control unit of the occurrence of an abnormality in the second control unit and the occurrence of an abnormality in the second termination device during operation; the second control unit performs the first switching control when the first monitoring control unit notifies the second control unit of an occurrence of an abnormality in the first control unit and an occurrence of an abnormality in the first terminal device in operation. Terminal equipment.

2. the second monitoring control unit transmits a notification of an abnormality occurring in the second control unit and a notification of an abnormality occurring in the second termination device during operation using a main signal line that transmits a main signal between the first transceiver unit and the second transceiver unit; the first monitoring control unit transmits, via the main signal line, a notification of an occurrence of an abnormality in the first control unit and a notification of an occurrence of an abnormality in the first termination device during operation; 2. The terminal device according to claim 1.

3. the main signal line is an optical transmission line, the first transceiver and the second transceiver transmit the main signal of an optical signal; 3. The terminal device according to claim 2.

4. the first control unit performs a process of notifying an external system of the occurrence of an abnormality in the second control unit when the first control unit is notified by the second monitoring control unit of the occurrence of an abnormality in the second control unit, and a process of notifying the external system of the recovery of the first control unit when the first control unit itself has recovered from a failure; The second control unit performs a process of notifying the external system of the occurrence of an abnormality in the first control unit when the occurrence of an abnormality in the first control unit is notified from the first monitoring control unit, and a process of notifying the external system of the recovery of the second control unit when the second control unit itself recovers from a failure.

2. The terminal device according to claim 1.

5. the first transmitting / receiving unit and the first monitoring control unit are mounted in the same package, the second transmitter / receiver and the second monitoring control unit are mounted in the same package; The terminal device according to any one of claims 1 to 4.

6. the first terminal device terminates an optical signal between the first terminal device and the first downstream device; the second termination device terminates an optical signal between the second downstream device and the second downstream device; 2. The terminal device according to claim 1.

7. A switching control method in an end station device including a first communication device and a second communication device, a first transmitting / receiving step in which the first terminal device in operation among the redundant first terminal devices of the first communication device transmits and receives signals to and from a first lower-level device; a second transmitting / receiving step in which a first transmitting / receiving unit of the first communication device transmits and receives a main signal, the main signal being a source or destination of which is a second lower-level device, to and from the second communication device; a first switching step in which a first control unit of the first communication device performs first switching control to switch the first terminal device in operation where an abnormality has occurred to a standby first terminal device when an abnormality has occurred in the first terminal device in operation; a third transmitting / receiving step in which the second terminal device in operation among the redundant second terminal devices of the second communication device transmits and receives signals to and from the second lower-level device; a fourth transmission / reception step in which a second transmission / reception unit of the second communication device receives the main signal transmitted in the second transmission / reception step, and transmits the received main signal to the second lower-level device via the second termination device, and transmits the main signal received from the second lower-level device in the third transmission / reception step to the first communication device; a second switching step in which a second control unit of the second communication device performs second switching control to switch the second terminal device in operation where an abnormality has occurred to the second terminal device in operation to a standby second terminal device when an abnormality has occurred in the second terminal device in operation; a first notification step in which a first monitoring control unit of the first communication device notifies the second communication device of the occurrence of an abnormality when an abnormality occurs in the first control unit and an abnormality occurs in the first terminal device during operation; a third switching step of performing the first switching control when the second control unit of the second communication device receives the notification of the occurrence of an abnormality in the first control unit and the occurrence of an abnormality in the first terminal device in operation; a second notification step in which a second monitoring control unit of the second communication device notifies the first communication device of the occurrence of an abnormality when an abnormality occurs in the second control unit and an abnormality occurs in the second terminal device during operation; a fourth switching step of performing the second switching control when the first control unit of the first communication device receives the notification of the occurrence of an abnormality in the second control unit and the occurrence of an abnormality in the second terminal device that is currently in operation; A switching control method comprising:

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