JP2012222555A - Optical transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continue signal transmission by executing protection changeover even when a signal fault occurs between an optical transmission device and a subordinate device.SOLUTION: The optical transmission device includes: a coupler 111 for branching signals from a subordinate device 103 into plural ones; optical transmission/reception parts 112 and 114 for transmitting the plurality of signals of the same contents branched by the coupler 111 to another optical transmission device 102, receiving the plurality of signals of the same contents from the other optical transmission device 102, and transmitting one of the signals to the side of the subordinate device 103; and optical reception parts 116 and 117 for detecting a signal fault between the optical transmission/reception parts 112 and 114 and the subordinate device 103. When the signal fault is detected, the optical reception parts 116 and 117 instruct the optical transmission/reception parts 112 and 114 to transmit, instead of the signal pertinent to the signal fault, another signal of the same contents as the signal to the side of the subordinate device 103.

Description

  The present invention relates to an optical transmission apparatus having a redundant configuration of a signal to be transmitted / received to / from another optical transmission apparatus and having a function of detecting a signal failure between the own apparatus and a lower apparatus. Is.

  In an optical transmission system, a protection method such as OUPSR (Optical Unidirectional Path Switch Ring) or OSPPR (Optical Shared Path Protection Ring) is often used as a redundant configuration of signals (see, for example, Patent Document 1).

  For example, in an OUPSR optical transmission system, normally, the optical transceiver of the first optical transmission apparatus divides the signal from the corresponding subordinate apparatus into an active system signal and a standby system signal, and outputs the second optical signal. Sending to the transmission device. In the second optical transmission device, the working optical signal is received by the working optical transceiver, and the standby signal is received by the standby optical transceiver. Then, the working side optical transceiver transmits the received working system signal to the lower device. On the other hand, the backup side optical transceiver stops the received backup system signal without transmitting it to the lower level device. The signal transmission from the second optical transmission apparatus to the first optical transmission apparatus also operates in the same manner.

  Here, when a failure occurs in the active signal between the first optical transmission device and the second optical transmission device, the active optical transmitter / receiver causes a failure in the active signal in the second optical transmission device. Is detected and signal transmission to the lower-level device is stopped. Further, the backup side optical transceiver transmits the received backup system signal to the lower level apparatus. As a result, even when a failure occurs in the working system signal between the first optical transmission apparatus and the second optical transmission apparatus, signal transmission can be performed by using the standby system signal instead of the working system signal. It is possible to continue. In this way, when a signal failure occurs, the operation of switching the transmission signal to the lower device is called protection switching.

JP 2006-191212 A

  In a conventional optical transmission system, protection switching is performed against signal failure between optical transmission apparatuses. However, when a signal failure occurs between the optical transmission device and the lower device, there is a problem that protection switching cannot be performed because there is no means for detecting the failure occurrence on the optical transmission device side. Therefore, when a failure occurs in the working signal between the optical transmission device and the lower device, the signal cannot be switched to the protection signal and the signal transmission cannot be continued.

  The present invention has been made to solve the above-described problems. Protection switching can be performed even when a signal failure occurs between an optical transmission apparatus and a lower-level apparatus, and signal transmission is continued. An object of the present invention is to provide an optical transmission device capable of performing the above.

  An optical transmission device according to the present invention transmits a coupler that branches a signal from a lower-level device into a plurality of signals, and a plurality of signals having the same contents branched by the coupler to another optical transmission device, and from the other optical transmission devices. An optical transmission / reception unit that receives a plurality of signals having the same content and transmits one of the signals to the lower-level device side, and an optical reception unit that detects a signal failure between the optical transmission / reception unit and the lower-level device. The optical receiver, when detecting a signal failure, transmits another signal having the same content as the signal to the lower-level device instead of the signal corresponding to the signal failure. It is an instruction.

  According to the present invention, since it is configured as described above, protection switching can be performed even when a signal failure occurs between the optical transmission apparatus and the lower-level apparatus, and signal transmission can be continued. High quality service can be provided.

It is a figure which shows the structure of the optical transmission system which concerns on Embodiment 1 of this invention (normal time). It is a flowchart which shows the operation | movement by the optical transmission system which concerns on Embodiment 1 of this invention (normal time). It is a figure which shows the structure of the optical transmission system which concerns on Embodiment 1 of this invention (at the time of a failure of an active system signal). It is a flowchart which shows the operation | movement by the optical transmission system concerning Embodiment 1 of this invention (at the time of failure occurrence). It is a figure which shows the structure of the optical transmission system which concerns on Embodiment 2 of this invention (normal time). It is a figure which shows the structure of the optical transmission system which concerns on Embodiment 2 of this invention (at the time of a failure of an active system signal). It is a figure which shows the structure of the optical transmission system which concerns on Embodiment 3 of this invention (normal time). It is a figure which shows the structure of the optical transmission system which concerns on Embodiment 3 of this invention (at the time of a failure of an active system signal). It is a flowchart which shows the operation | movement by the optical transmission system which concerns on Embodiment 3 of this invention (at the time of failure occurrence). It is a figure which shows the structure of the optical transmission system which concerns on Embodiment 3 of this invention (at the time of a failure of a 1st backup system signal).

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
1 is a diagram showing a configuration of an optical transmission system according to Embodiment 1 of the present invention.
As shown in FIG. 1, the optical transmission system includes optical transmission apparatuses 101 and 102 that transmit and receive signals to each other, a lower-level apparatus 103 that transmits and receives signals to and from the optical transmission apparatus 101, and an optical transmission apparatus 102. It is comprised from the low-order apparatus 104 which transmits / receives a signal between. In addition, since the optical transmission apparatuses 101 and 102 have a redundant signal configuration, the signals from the lower-level apparatuses 103 and 104 are branched into two, and transmitted and received as active system signals 141 and 142 and standby system signals 143 and 144. Yes.

  The optical transmission apparatus 101 includes couplers 111, 113, 115, 118, optical transceivers 112, 114, and optical receivers 116, 117. In normal times, it is assumed that the optical transceiver 112, the optical coupler 113, and the optical receiver 116 are active function units that receive and process the active signal 142, and the optical transceiver 114, the optical coupler 115, and the optical receiver. The operation content at that time will be described assuming that 117 is a standby function unit that receives and processes the standby signal 144.

The coupler 111 divides the signal 131 transmitted from the lower apparatus 103 into two, transmits one signal to the optical transceiver 112, and transmits the other signal to the optical transceiver 114.
The optical transmitter / receiver 112 transmits the signal from the coupler 111 to the optical transmitter / receiver 122 of the optical transmission apparatus 102 as the active system signal 141, and receives the active system signal 142 from the optical transmitter / receiver 122 and transmits it to the coupler 113. To do.
Further, the optical transceiver 112 monitors the received active signal 142 to detect whether a signal failure has occurred between itself and the optical transceiver 122. Here, when the optical transceiver 112 detects a signal failure between itself and the optical transceiver 122, the optical transceiver 112 stops signal transmission to the lower device 103 side by itself and Thus, it instructs to start signal transmission to the lower device 103 side. Further, when a signal failure is detected by the optical receiver 116, the optical transmitter / receiver 112 stops signal transmission to the lower device 103 side by the own apparatus according to an instruction from the optical receiver 116.
The coupler 113 branches the working signal 142 from the optical transceiver 112 into two, transmits one signal to the coupler 118, and transmits the other signal to the optical receiver 116.

The optical transmitter / receiver 114 transmits a signal from the coupler 111 to the optical transmitter / receiver 124 of the optical transmission apparatus 102 as a standby system signal 143, and receives the standby system signal 144 from the optical transmitter / receiver 124. Then, the optical transceiver 114 stops the received standby system signal 144 without transmitting it to the coupler 115 during normal times (when no signal failure is detected by the optical transceiver 112 or the optical receiver 116). On the other hand, when a failure occurs in the working system signal 142 (when a signal failure is detected by the optical transceiver 112 or the optical receiver 116), the received standby system is received in accordance with an instruction from the optical transceiver 112 or the optical receiver 116. Signal 144 is transmitted to coupler 115.
The coupler 115 branches the standby system signal 144 from the optical transceiver 114 into two, transmits one signal to the coupler 118, and transmits the other signal to the optical receiver 117.

The optical receiver (optical receiver) 116 monitors the signal from the coupler 113 and detects whether a signal failure has occurred between the optical transceiver 112 and the coupler 113. Here, when the optical receiver 116 detects a signal failure between the optical transmitter / receiver 112 and the coupler 113, the optical receiver 116 stops signal transmission to the lower device 103 side with respect to the optical transmitter / receiver 112. And instruct the optical transceiver 114 to start signal transmission to the lower device 103 side.
The optical receiver (optical receiver) 117 monitors the signal from the coupler 115 and detects whether a signal failure has occurred between the optical transceiver 114 and the coupler 115. While functioning as a functional unit, no signal flows and does not operate.
The coupler (second coupler) 118 collects signal lines for transmitting signals from the optical transceivers 112 and 114 to the lower device 103 side into a single signal line, and signals from the coupler 113 or the coupler 115. Is transmitted to the lower apparatus 103.

  The optical transceivers 112 and 114 transmit a plurality of signals having the same contents branched by the coupler 111 to the optical transmission apparatus 102 and receive a plurality of signals having the same contents from the optical transmission apparatus 102, It functions as an optical transmission / reception unit that transmits one signal to the lower apparatus 103 side.

In addition, when a failure occurs in the active system signal 142 and protection switching is performed (when the standby system signal 144 is switched to the active system), the standby system function section is connected to the above-described active system function section. The same operation is performed.
Also, the optical transmission apparatus 102 has the same configuration as that of the optical transmission apparatus 101, and description of the operation of each unit is omitted. In normal times, it is assumed that the optical transceiver 122, the optical coupler 123, and the optical receiver 126 are active function units that receive and process the active signal 141, and the optical transceiver 124, the optical coupler 125, and the optical receiver. It is assumed that 127 is a standby function unit that receives and processes the standby signal 143.

Next, the operation of the optical transmission system configured as described above will be described.
First, an operation at the time of signal transmission from the optical transmission apparatus 101 to the optical transmission apparatus 102 at the normal time will be described. FIG. 2 is a flowchart showing an operation (normal time) by the optical transmission system according to the first embodiment of the present invention.
In the normal operation by the optical transmission system, as shown in FIG. 2, first, the coupler 111 splits the signal 131 from the lower apparatus 103 into two, transmits one signal to the optical transceiver 112, and transmits the other signal. The signal is transmitted to the optical transceiver 114 (step ST21).

  Next, the optical transceiver 112 transmits the signal from the coupler 111 to the optical transceiver 122 as the active system signal 141, and the optical transceiver 114 transmits the signal from the coupler 111 to the optical transceiver 124 as the standby system signal 143. (Step ST22).

  Next, the optical transceiver 122 receives the working system signal 141 from the optical transceiver 112, and the optical transceiver 124 receives the standby system signal 143 from the optical transceiver 114 (step ST23). Then, the optical transceiver 122 transmits the working system signal 141 to the coupler 123. On the other hand, the optical transmitter / receiver 124 transmits this standby system signal 143 to the lower level device 104 side (coupler 125) during normal times (when no signal failure is detected by the optical transmitter / receiver 122 or the optical receiver 126). do not do. The optical transmitter / receiver 122 monitors the received active signal 141 and detects a signal failure between itself and the optical transmitter / receiver 112.

Next, the coupler 123 splits the working system signal 141 from the optical transceiver 122 into two, transmits one signal to the subordinate device 104 via the coupler 128, and transmits the other signal to the optical receiver 126 (step). ST24). Then, the optical receiver 126 monitors a signal from the coupler 123 and detects a signal failure between the optical transceiver 122 and the coupler 123.
As a result, in the normal time, the standby signal 143 is not transmitted to the lower-level device 104, and only the active signal 141 is transmitted.

Next, as shown in FIG. 3, the operation in the case where a signal failure occurs between the optical transceiver 122 and the coupler 123 (portion A) will be described. FIG. 4 is a flowchart showing the operation (when a failure occurs) by the optical transmission system according to Embodiment 1 of the present invention.
In the operation at the time of failure of the working signal 141 by the optical transmission system, as shown in FIG. 4, the optical receiver 126 detects a signal failure between the optical transceiver 122 and the coupler 123 (step ST41). 'YES'), the optical transceiver 122 is instructed to stop signal transmission to the lower device 104 side, and the optical transceiver 124 is started to transmit signal to the lower device 104 side. An instruction is given (step ST42). As a result, the optical transceiver 122 stops signal transmission to the lower device 104 side.
Next, the optical transceiver 124 transmits the received standby signal 143 to the coupler 125 according to the instruction from the optical receiver 126 (step ST43).

  Next, the coupler 125 divides the standby system signal 143 from the optical transceiver 124 into two branches, transmits one signal to the subordinate device 104 via the coupler 128, and transmits the other signal to the optical receiver 127 (step). ST44). The optical receiver 127 monitors the signal from the coupler 125 and detects a signal failure between the optical transceiver 124 and the coupler 125.

By operating in this way, even when a signal failure occurs between the optical transceiver 122 and the lower level device 104 (between the optical transceiver 122 and the coupler 123), this signal failure can be detected. The active system signal 141 can be switched to the standby system signal 143.
Note that a signal failure between the optical transmission apparatuses 101 and 102 (between the optical transmitter / receiver 112 and the optical transmitter / receiver 122) can be switched by detecting the optical transmitter / receiver 122 as usual. Is possible.

  In the above description, the signal transmission from the optical transmission apparatus 101 to the optical transmission apparatus 102 has been described. However, the same applies to the case of signal transmission from the optical transmission apparatus 102 to the optical transmission apparatus 101.

  As described above, according to the first embodiment, the signal flowing through each signal line between the optical transceivers 112, 114 (122, 124) and the coupler 118 (128) is monitored to detect a signal failure. Since the optical receivers 116 and 117 (126 and 127) are provided, protection switching is performed even when a signal failure occurs between the optical transmission apparatus 101 (102) and the lower apparatus 103 (104). Since signal transmission can be continued, a high-quality service can be provided.

Embodiment 2. FIG.
In the first embodiment, for example, in the optical transmission apparatus 101, the case where each signal transmitted between each of the optical transceivers 112 and 114 and the coupler 118 is monitored has been described. A case where a single signal transmitted in the subsequent stage is monitored will be described.
FIG. 5 is a diagram showing a configuration of an optical transmission system according to Embodiment 2 of the present invention.
As shown in FIG. 5, the optical transmission system includes optical transmission devices 201 and 202 that transmit and receive signals to each other, a lower-level device 203 that transmits and receives signals to and from the optical transmission device 201, and an optical transmission device 202. It is comprised from the low-order apparatus 204 which transmits / receives a signal between. Further, since the transmission apparatuses 201 and 202 have a redundant signal configuration, the signals from the lower-level apparatuses 203 and 204 are branched into two, and are transmitted and received as working system signals 241 and 242 and standby system signals 243 and 244. .

  The optical transmission apparatus 201 includes optical couplers 211, 214, 215, optical transceivers 212, 213, and an optical receiver 216. In normal times, the optical transceiver 212 is an active function unit that receives and processes the active signal 242, and the optical transceiver 213 is an auxiliary function unit that receives and processes the standby signal 244. The operation contents at that time will be described.

The coupler 211 splits the signal 231 transmitted from the lower level device 203 into two, transmits one signal to the optical transceiver 212, and transmits the other signal to the optical transceiver 213.
The optical transceiver 212 transmits the signal from the coupler 211 to the optical transceiver 222 of the optical transmission apparatus 202 as the active system signal 241, and receives the active system signal 242 from the optical transceiver 222 and transmits it to the coupler 214. To do.
Further, the optical transceiver 212 monitors the received active signal 242 to detect whether a signal failure has occurred between itself and the optical transceiver 222. If the optical transceiver 212 detects a signal failure between itself and the optical transceiver 222, the optical transceiver 212 stops signal transmission to the lower device 203 side by itself and Thus, it instructs to start signal transmission to the lower device 203 side. In addition, when a signal failure is detected by the optical receiver 216, the optical transceiver 212 stops signal transmission by the own device to the lower device 203 side in accordance with an instruction from the optical receiver 216.

  The optical transmitter / receiver 213 transmits the signal from the coupler 211 as the standby system signal 243 to the optical transmitter / receiver 223 of the optical transmission apparatus 202, and receives the standby system signal 244 from the optical transmitter / receiver 223. Then, the optical transceiver 213 stops the received standby system signal 244 without transmitting it to the coupler 214 during normal times (when no signal failure is detected by the optical transceiver 212 or the optical receiver 216). On the other hand, when a failure of the active system signal 242 occurs (when a signal failure is detected by the optical transceiver 212 or the optical receiver 216), the received standby system is received in accordance with an instruction from the optical transceiver 212 or the optical receiver 216. Signal 244 is transmitted to coupler 214.

The coupler (second coupler) 214 collects signal lines for transmitting signals from the optical transceivers 212 and 213 to the lower device 203 side into a single signal line. The optical transceiver 212 or the optical transceiver A signal from 213 is transmitted to the coupler 215.
The coupler 215 splits the signal from the coupler 214 into two, transmits one signal to the lower order device 203, and transmits the other signal to the optical receiver 216.

  The optical receiver (optical receiver) 216 monitors the signal from the coupler 215 to detect whether a signal failure has occurred between the optical transmitter / receiver 212 and the coupler 215 in a normal state, and after switching the protection. (After the standby system signal 244 is switched to the active system) is for detecting whether a signal failure has occurred between the optical transceiver 213 and the coupler 215. Here, when the optical receiver 216 detects a signal failure between the optical transmitter / receiver 212 and the coupler 215, the optical receiver 216 stops signal transmission to the lower device 203 side with respect to the optical transmitter / receiver 212. And instruct the optical transceiver 213 to start signal transmission to the lower device 203 side. In addition, when a signal failure is detected between the optical transceiver 213 and the coupler 215 after protection switching, the optical transceiver 213 is instructed to stop signal transmission to the lower level device 203 side. .

  The optical transceivers 212 and 213 transmit a plurality of signals having the same content branched by the coupler 211 to the optical transmission device 202, and receive a plurality of signals having the same content from the optical transmission device 202. It functions as an optical transmission / reception unit that transmits one signal to the lower apparatus 203 side.

Further, when a failure occurs in the active system signal 242 and protection switching is performed, the standby system function unit performs the same operation as the above-described active system function unit.
Also, the optical transmission apparatus 202 has the same configuration as that of the optical transmission apparatus 201, and the description of the operation of each unit is omitted. In the following description, it is assumed that the optical transceiver 222 is an active function unit that receives and processes the active signal 241, and the optical transceiver 223 is an auxiliary function unit that receives and processes the standby signal 243. .

Next, the operation of the optical transmission system configured as described above will be described.
First, an operation at the time of signal transmission from the optical transmission apparatus 201 to the optical transmission apparatus 202 at the normal time will be described. The normal operation outline of the optical transmission system according to the second embodiment is the same as the normal operation outline of the optical transmission system according to the first embodiment shown in FIG. 2 and will be described with reference to FIG. .
In normal operation by the optical transmission system, as shown in FIG. 2, first, the coupler 211 branches the signal 231 from the lower device 203 into two, transmits one signal to the optical transceiver 212, The signal is transmitted to the optical transceiver 213 (step ST21).

  Next, the optical transceiver 212 transmits the signal from the coupler 211 to the optical transceiver 222 as the active signal 241, and the optical transceiver 213 transmits the signal from the coupler 211 to the optical transceiver 223 as the standby signal 243. (Step ST22).

  Next, the optical transceiver 222 receives the active system signal 241 from the optical transceiver 212, and the optical transceiver 223 receives the standby system signal 243 from the optical transceiver 213 (step ST23). Then, the optical transceiver 222 transmits the working system signal 241 to the coupler 225 via the coupler 224. On the other hand, the optical transmitter / receiver 223 transmits the standby signal 243 to the lower level device 204 side (coupler 224) during normal times (when no signal failure is detected by the optical transmitter / receiver 222 or the optical receiver 226). do not do. Further, the optical transceiver 222 monitors the received active signal 241 and detects a signal failure between itself and the optical transceiver 212.

Next, the coupler 225 splits the working system signal 241 from the optical transceiver 222 into two, transmits one signal to the lower order device 204, and transmits the other signal to the optical receiver 226 (step ST24). Then, the optical receiver 226 monitors a signal from the coupler 225 and detects a signal failure between the optical transceiver 222 and the coupler 225.
As a result, in the normal time, the standby signal 243 is not transmitted to the lower-level device 204, and only the active signal 241 is transmitted.

Next, as shown in FIG. 6, the operation in the case where a signal failure occurs between the optical transceiver 222 and the coupler 224 (the part denoted by reference symbol B) will be described. The operation outline when a failure occurs in the optical transmission system according to the second embodiment is the same as the operation outline when a failure occurs in the optical transmission system according to the first embodiment shown in FIG. 4, and will be described with reference to FIG. I do.
In the operation at the time of failure of the working signal 241 by the optical transmission system, as shown in FIG. 4, the optical receiver 226 detects a signal failure between the optical transceiver 222 and the coupler 225 (step ST41). 'YES'), the optical transceiver 222 is instructed to stop signal transmission to the lower device 204 side, and the optical transceiver 223 is started to transmit signal to the lower device 204 side. An instruction is given (step ST42). As a result, the optical transceiver 222 stops signal transmission to the lower device 204 side.
Next, in accordance with an instruction from the optical receiver 226, the optical transceiver 223 transmits the received standby signal 243 to the coupler 225 via the coupler 224 (step ST43).

  Next, the coupler 225 splits the standby system signal 243 from the optical transceiver 223 into two, transmits one signal to the lower order device 204, and transmits the other signal to the optical receiver 226 (step ST44). Then, the optical receiver 226 monitors the signal from the coupler 225 and performs signal failure detection between the optical transceiver 223 and the coupler 225.

By operating in this way, even when a signal failure occurs between the optical transceiver 222 and the lower level device 204 (between the optical transceiver 222 and the coupler 225), this signal failure can be detected. The active system signal 241 can be switched to the standby system signal 243.
It should be noted that protection switching can be performed by detecting a signal failure between the optical transmission apparatuses 201 and 202 (between the optical transmitter / receiver 212 and the optical transmitter / receiver 222) by the optical transmitter / receiver 222 as in the past. Is possible.

  In the above description, the signal transmission from the optical transmission apparatus 201 to the optical transmission apparatus 202 has been described. However, the same applies to the case where signal transmission from the optical transmission apparatus 202 to the optical transmission apparatus 201 is performed.

  As described above, according to the second embodiment, an optical receiver 216 (monitoring a signal failure by monitoring a signal flowing through a signal line between the coupler 214 (224) and the lower device 203 (204). 226) is provided, it is not necessary to provide a plurality of optical receivers. In addition to the effects of the first embodiment, the number of parts can be reduced, and the cost can be reduced.

Embodiment 3 FIG.
In the first and second embodiments, the case where one set of the active system signal and the standby system signal is provided is shown, but in the third embodiment, the case where the active system signal and a plurality of standby system signals are provided is shown.
FIG. 7 is a diagram showing a configuration of an optical transmission system according to Embodiment 3 of the present invention.
As shown in FIG. 7, the optical transmission system includes optical transmission devices 301 and 302 that transmit and receive signals to each other, a lower-level device 303 that transmits and receives signals to and from the optical transmission device 301, and an optical transmission device 302. And a lower-level device 304 that transmits and receives signals between them. Further, since the transmission apparatuses 301 and 302 have a redundant signal configuration, the signals from the lower-level apparatuses 303 and 304 are branched into three, and the active system signals 341 and 342, the first standby system signals 343 and 344, and the second Are transmitted and received as standby system signals 345 and 346. It is assumed that the priorities of the respective signals are in the order of the active system signals 341 and 342, the first standby system signals 343 and 344, and the second standby system signals 345 and 346.

  The optical transmission device 301 includes optical couplers 311, 315, 316, optical transceivers 312 to 314 and an optical receiver 317. In a normal state, the optical transceiver 312 is an active function unit that receives and processes the active signal 342, and the optical transmitter and receiver 313 receives and processes the first standby signal 344. The operation contents at that time will be described assuming that the optical transmitter / receiver 314 is a second standby system functional unit that receives and processes the second standby system signal 346.

The coupler 311 branches the signal 331 transmitted from the lower-level device 303 into three branches and transmits them to the optical transceivers 312 to 314, respectively.
The optical transmitter / receiver 312 transmits the signal from the coupler 311 to the optical transmitter / receiver 322 of the optical transmission apparatus 302 as the active system signal 341, and receives the active system signal 342 from the optical transmitter / receiver 322 and transmits it to the coupler 315. To do.
Further, the optical transceiver 312 monitors the received active signal 342 and detects whether a signal failure has occurred between itself and the optical transceiver 322. Here, when the optical transceiver 312 detects a signal failure between itself and the optical transceiver 322, the optical transceiver 312 stops signal transmission to the lower device 303 side by itself and follows the active system signal 342. To the optical transceiver 313 that receives the signal having the higher priority (first standby signal 344), the signal transmission to the subordinate device 303 is started. Further, when a signal failure is detected by the optical receiver 317, the optical transmitter / receiver 312 stops signal transmission by the own device to the lower device 303 side in accordance with an instruction from the optical receiver 317.

  The optical transceiver 313 transmits the signal from the coupler 311 as the first standby system signal 343 to the optical transceiver 323 of the optical transmission device 302 and receives the first standby system signal 344 from the optical transceiver 323. Is. Then, the optical transceiver 313 does not transmit the received first standby signal 344 to the coupler 315 during normal times (when no signal failure is detected by the optical transceiver 312 or the optical receiver 317). Stop. On the other hand, when the failure of the active signal 342 occurs (when a signal failure is detected by the optical transceiver 312 or the optical receiver 317), the received first signal 342 is received in accordance with an instruction from the optical transceiver 312 or the optical receiver 317. The standby system signal 344 is transmitted to the coupler 315.

  The optical transmitter / receiver 314 transmits the signal from the coupler 311 to the optical transmitter / receiver 324 of the optical transmission apparatus 302 as the second standby system signal 345, and receives the second standby system signal 346 from the optical transmitter / receiver 324. Is. Then, the optical transceiver 314 stops the received second backup signal 346 without transmitting it to the coupler 316 at the normal time or when the failure of the active signal 342 occurs. On the other hand, when a failure occurs in the first standby system signal 344 (when a signal failure is detected by the optical transceiver 313 or the optical receiver 317), reception is performed according to an instruction from the optical transceiver 313 or the optical receiver 317. The second standby system signal 346 is transmitted to the coupler 316.

The coupler 315 transmits a signal from the optical transceiver 312 or the optical transceiver 313 to the coupler 316.
The coupler 316 divides the signal from the coupler 315 or the optical transceiver 314 into two, transmits one signal to the subordinate device 303, and transmits the other signal to the optical receiver 317.
The couplers 315 and 316 function as second couplers that combine signal lines that transmit signals from the optical transceivers 312 to 314 to the lower-level device 303 side into a single signal line.

  The optical receiver (optical receiving unit) 317 monitors the signal from the coupler 316 and detects whether or not a signal failure has occurred between the optical transceiver 312 and the coupler 316 in the normal state. After protection switching (after the first standby system signal 344 is switched to the active system), it is detected whether a signal failure has occurred between the optical transceiver 313 and the coupler 316, and the second protection switching is performed. After that (when the second standby system signal 346 is switched to the active system), it is detected whether a signal failure has occurred between the optical transceiver 314 and the coupler 316. Here, when the optical receiver 317 detects a signal failure between the optical transmitter / receiver 312 and the coupler 316, the optical receiver 317 stops signal transmission to the lower device 303 side with respect to the optical transmitter / receiver 312. To the optical transceiver 313 that receives the signal having the second highest priority (the first standby signal 344) after the active signal 342, to start signal transmission to the lower device 303 side. To do. In addition, when a signal failure is detected between the optical transceiver 313 and the coupler 316 after the first protection switching, the signal transmission to the lower device 303 side is stopped with respect to the optical transceiver 313. To the optical transceiver 314 that receives the signal with the second highest priority (the second standby signal 346) after the first standby signal 344, starts signal transmission to the lower-level device 303 side. To instruct. In addition, when a signal failure is detected between the optical transceiver 314 and the coupler 316 after the second protection switching, the signal transmission to the lower level device 303 side is stopped with respect to the optical transceiver 314. Instruct.

  The optical transceivers 312 to 314 transmit a plurality of signals having the same content branched by the coupler 311 to the optical transmission device 302 and receive a plurality of signals having the same content from the optical transmission device 302. It functions as an optical transmitter / receiver that transmits one signal to the lower apparatus 303 side.

Further, when a failure occurs in the working system signal 342 and the first protection switching is performed, the first standby function unit performs the same operation as the above working function unit. Further, when a failure occurs in the first standby system signal 344 and the second protection switching is performed, the second standby system function unit performs the same operation as the above-described active system function unit. .
The optical transmission apparatus 302 has the same configuration as that of the optical transmission apparatus 301, and the description of the operation of each unit is omitted. In a normal state, it is assumed that the optical transceiver 322 is an active function unit that receives and processes the active signal 341, and the optical transceiver 323 receives and processes the first standby signal 343. It is assumed that the optical transmission / reception device 324 is a second standby system functional unit that receives and processes the second standby system signal 345.

Next, the operation of the optical transmission system configured as described above will be described.
First, an operation when signal transmission is performed from the optical transmission apparatus 301 to the optical transmission apparatus 302 in the normal state will be described. The normal operation outline of the optical transmission system according to the third embodiment is the same as the normal operation outline of the optical transmission system according to the first embodiment shown in FIG. 2, and will be described with reference to FIG. .
In the normal operation by the optical transmission system, as shown in FIG. 2, first, the coupler 311 branches the signal 331 from the lower apparatus 303 into three branches and transmits them to the optical transceivers 313 to 314, respectively (step ST21). .

  Next, the optical transmitter / receiver 312 transmits the signal from the coupler 311 to the optical transmitter / receiver 322 as the active signal 341, and the optical transmitter / receiver 313 receives the signal from the coupler 311 as the first standby signal 343. The optical transceiver 314 transmits the signal from the coupler 311 to the optical transceiver 324 as the second standby signal 345 (step ST22).

  Next, the optical transceiver 322 receives the working system signal 341 from the optical transceiver 312, the optical transceiver 323 receives the first standby system signal 343 from the optical transceiver 313, and the optical transceiver 324 Then, the second standby system signal 345 is received from the optical transceiver 314 (step ST23). Then, the optical transceiver 322 transmits the working system signal 341 to the coupler 326 via the coupler 325. On the other hand, the optical transceivers 323 and 324 normally use the first and second standby signals 343 and 345 as lower-level devices when no signal failure is detected by the optical transceiver 322 or the optical receiver 327. No transmission is made to the 304 side (couplers 325 and 326). Further, the optical transceiver 322 monitors the received active signal 341 and detects a signal failure between itself and the optical transceiver 312.

Next, the coupler 326 splits the working system signal 341 from the optical transceiver 322 into two, transmits one signal to the subordinate device 304, and transmits the other signal to the optical receiver 327 (step ST24). The optical receiver 327 monitors a signal from the coupler 326 and detects a signal failure between the optical transceiver 322 and the coupler 326.
As a result, in the normal time, the first and second standby signals 343 and 345 are not transmitted to the lower-level device 304, and only the active signal 341 is transmitted.

Next, as shown in FIG. 8, the operation in the case where a signal failure occurs between the optical transceiver 322 and the coupler 325 (portion C) will be described. FIG. 9 is a flowchart showing an operation (when a failure occurs) by the optical transmission system according to Embodiment 3 of the present invention.
In the operation when the failure of the active signal 341 by the optical transmission system occurs, as shown in FIG. 9, the optical receiver 327 detects a signal failure between the optical transceiver 322 and the coupler 326 (step ST91). 'YES'), the optical transceiver 322 is instructed to stop signal transmission to the lower-level device 304 side, and the signal having the next highest priority after the active system signal 341 (first standby system signal 343) Is transmitted to the lower level apparatus 304 side (step ST92). As a result, the optical transceiver 322 stops signal transmission to the lower device 304 side.
Next, the optical transceiver 323 transmits the received first standby system signal 343 to the coupler 326 via the coupler 325 in accordance with the instruction from the optical receiver 327 (step ST93).

  Next, the coupler 326 splits the first standby signal 343 from the optical transceiver 323 into two branches, transmits one signal to the subordinate device 304, and transmits the other signal to the optical receiver 327 (step ST94). . The optical receiver 327 monitors a signal from the coupler 326 and detects a signal failure between the optical transceiver 323 and the coupler 326. Note that the optical transceiver 324 continues the transmission stop state of the received second standby signal 345.

By operating in this way, even when a signal failure occurs between the optical transceiver 322 and the lower level device 304 (between the optical transceiver 322 and the coupler 326), this signal failure can be detected. The active system signal 341 can be switched to the first standby system signal 343 having the next highest priority.
Note that a signal failure between the optical transmission devices 301 and 302 (between the optical transceiver 312 and the optical transceiver 322) can be switched by detecting the optical transceiver 322 as usual. Is possible.

Next, as shown in FIG. 10, the operation when a signal failure occurs between the optical transceiver 323 and the coupler 325 after the first protection switching (part D) will be described. The operation outline when the failure of the first standby signal 343 by the optical transmission system according to the third embodiment is the same as the operation outline when the failure of the active signal 341 shown in FIG. The explanation will be given.
In the operation at the time of the failure of the first standby signal 343 by the optical transmission system, the optical receiver 327 detects a signal failure between the optical transceiver 323 and the coupler 326 as shown in FIG. (Step ST91 'YES'), the optical transceiver 323 is instructed to stop signal transmission to the low-level device 304 side, and the signal with the second highest priority (second signal) Of the standby system signal 345), the optical transceiver 324 is instructed to start signal transmission to the lower-level device 304 side (step ST92). As a result, the optical transceiver 323 stops signal transmission to the lower device 304 side.
Next, the optical transceiver 324 transmits the received second standby signal 345 to the coupler 326 in accordance with the instruction from the optical receiver 327 (step ST93).

  Next, the coupler 326 splits the second standby signal 345 from the optical transceiver 324 into two, transmits one signal to the lower order device 304, and transmits the other signal to the optical receiver 327 (step ST94). . The optical receiver 327 monitors a signal from the coupler 326 and detects a signal failure between the optical transceiver 324 and the coupler 326.

By operating in this way, even if a signal failure occurs between the optical transceiver 323 and the lower level device 304 (between the optical transceiver 323 and the coupler 326) after the first protection switching, A signal failure can be detected, and the first standby signal 343 can be switched to the second standby signal 345 having the next highest priority.
Note that a signal failure between the optical transmission devices 301 and 302 (between the optical transmitter / receiver 313 and the optical transmitter / receiver 323) can be switched by detecting the optical transmitter / receiver 323 as usual. Is possible.

  In the above description, the signal transmission is performed from the optical transmission apparatus 301 to the optical transmission apparatus 302. However, the same applies to the case where signal transmission is performed from the optical transmission apparatus 302 to the optical transmission apparatus 301.

  As described above, according to the third embodiment, an active system signal and a plurality of standby system signals are provided, and priorities for transmission to the lower devices 303 and 304 are added to the respective signals. Since the protection switching is performed according to the priority order, in addition to the effects in the first embodiment, the second protection switching is performed when a signal failure further occurs after the first protection switching. Can respond flexibly.

In the third embodiment, the case where one working system signal 341 and 342 and two standby system signals 343 to 346 are used has been described. However, the present invention is not limited to this, and three or more standby system signals are used. May be.
Further, in the third embodiment, the optical receivers are arranged downstream of the couplers 325 and 326 that combine the signal lines through which the working signals 341 and 342 and the first and second standby signals 343 to 346 pass into a single signal line. As shown in the first embodiment, the optical receiver 327 may be provided before the couplers 325 and 326 as in the first embodiment.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  101, 102 Optical transmission device, 103, 104 Subordinate device, 111, 113, 115, 118 Coupler, 112, 114 Optical transceiver, 116, 117 Optical receiver, 121, 123, 125, 128 Coupler, 122, 124 Optical transmission / reception 126, 127 optical receiver, 131-134 signal, 141, 142 active system signal, 143, 144 standby system signal, 201, 202 optical transmission device, 203, 204 subordinate device, 211, 214, 215 coupler, 212, 213 optical transceiver, 216 optical receiver, 221, 224, 225 coupler, 222, 223 optical transceiver, 226 optical receiver, 231 to 234 signal, 241, 242 active system signal, 243, 244 standby system signal, 301, 302 Optical transmission device, 303, 304 Subordinate device, 311, 315, 31 Couplers, 312-314 Optical transceivers, 317 Optical receivers, 321, 325, 326 Couplers, 322-314 Optical transceivers, 327 Optical receivers, 331-334 signals, 341, 342 Working system signals, 343, 344 First , 345, 346 Second standby signal.

Claims (4)

In an optical transmission device having a redundant configuration of signals to be transmitted and received with other optical transmission devices,
A coupler for branching a signal from a subordinate device into a plurality,
A plurality of signals having the same contents branched by the coupler are transmitted to the other optical transmission apparatus, a plurality of signals having the same contents from the other optical transmission apparatuses are received, and one of the signals is sent to the lower order An optical transceiver for transmitting to the device side;
An optical receiver that detects a signal failure between the optical transceiver and the lower-level device;
When the optical receiving unit detects a signal failure, the optical receiving unit transmits another signal having the same content as the signal to the lower-level device instead of the signal corresponding to the signal failure. An optical transmission device characterized in that The optical transceiver includes a plurality of optical transceivers that receive different predetermined signals from among a plurality of signals having the same contents from the other optical transmission devices,
A second coupler that combines the signal lines for transmitting the signals from the optical transceivers to the lower device side into a single signal line;
The optical transmission device according to claim 1, wherein the optical receiver monitors signals transmitted through the signal lines. The optical transceiver includes a plurality of optical transceivers that receive different predetermined signals from among a plurality of signals having the same contents from the other optical transmission devices,
A second coupler that combines the signal lines for transmitting the signals from the optical transceivers to the lower device side into a single signal line;
The optical transmission apparatus according to claim 1, wherein the optical receiving unit monitors a signal transmitted through the single signal line. Each signal is given a priority when transmitting to the lower-level device,
When the optical reception unit detects a signal failure, the optical transmission / reception unit outputs a signal having the next highest priority to the signal among the other signals having the same content as the signal corresponding to the signal failure. The optical transmission apparatus according to claim 1, wherein an instruction to transmit to a lower apparatus side is given.

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