JP4869983B2 - Optical transmission system and optical transmission device - Google Patents

Description

  The present invention relates to an optical transmission system and an optical transmission apparatus that perform switching of an optical path for a redundantly configured optical path.

  In recent years, with the increase in speed and capacity of an optical communication system, it is desired to quickly restore communication even when a line failure occurs. For this reason, in optical communication systems, redundancy of optical lines and optical paths and redundancy of optical transmission devices have been performed. For example, a plurality of optical cross-connects (PXC) for setting / switching optical paths are introduced in an optical communication system, and setting / switching of optical paths according to traffic demand by PXC, and required optical path reliability. There is a technique for switching transmission lines when a failure occurs according to the characteristics.

  For control of transmission path switching, GMPLS (Generalized Multi Protocol Label Switching) protocol, etc., which is being standardized by IETF (Internet Engineering Task Force), is used. In this GMPLS, for example, the working path is between the first PXC (optical path start point) and the second PXC (optical path end point), and the second PXC passes from the first PXC to the third PXC. The transmission path switching between the working path and the backup path can be performed for a network in which the path up to (the detour path) is a backup path.

  For example, when a failure occurs in the link between the first PXC and the second PXC when the optical path is established between the first PXC and the second PXC, the optical signal is transmitted through the second PXC. A loss of light (LOL) is detected. Then, the second PXC transmits a failure to the first PXC, which is the starting point of the optical path, by a RSVP (Resource reSerVation Protocol) Notify message. The first PXC releases the optical path between the first PXC and the second PXC, which is the working path, by a Path Tear message, and a new optical path route (the third PXC is excluded) from which the failure point has been removed. Bypass path) is calculated, and the bypass path is established by the Path / Resv message.

  In addition, in a core network in which an optical cross connect (PXC) is introduced, high reliability is required, so it is necessary to improve the reliability of the PXC itself. For this reason, in the core network in which PXC is introduced, the optical switch for switching the optical path is set in a redundant configuration to set / switch the optical path. In order to make the optical switch in the PXC redundant, in the PXC, the input signal is branched into two by an optical coupler and distributed to the working optical switch and the spare optical switch. The output 2 × 1 switch selects either the signal from the active optical switch or the signal from the backup optical switch as an output signal. In PXC, an optical monitor is provided on each of the input side and the output side. Based on the combination of the monitor outputs of these two optical monitors, it is determined whether there is a device failure (such as an optical switch failure) or a transmission line failure. Is doing.

  For example, the PXC determines that there is a device failure when the optical monitor on the output side detects a light break and the optical monitor on the input side is normal. The PXC determines that a transmission path failure has occurred when the output side optical monitor detects a light break and the input side optical monitor is abnormal. Then, in PXC, when it is determined that there is a device failure, switching to a spare optical switch is performed by switching the 2 × 1 switch on the output side.

  As a technique for switching an optical line, the optical line switching apparatus described in Patent Document 1 is an optical line switching apparatus that switches a line from one duplexed line to the other, and the input light level is a predetermined value or less. After that, the optical line is switched only when the input light level below the predetermined value continues for a predetermined protection time.

  In addition, the optical transmission device described in Patent Document 2 branches and monitors the input signal, and when an input disconnection is detected at all monitoring points, it is determined as a transmission path failure, and an input disconnection is detected at some monitoring points. A device failure is determined, and the redundant path is switched based on the determination result.

JP 2003-218793 A JP-A-8-84116

  However, the former prior art has a problem in that the optical path switching device itself is not reliable because the optical path cannot be switched in the optical line switching device. In the latter prior art, the transmission paths are not redundantly connected, so that there is a problem that a detour path cannot be established when a failure occurs in the link between the optical transmission apparatuses.

  In addition, when the former prior art and the latter prior art are combined and transmission path switching by GMPLS and intra-device redundancy switching are simultaneously performed, an optical path switching result unintended by the network operator is obtained. That is, when an optical path is established between the starting point side PXC and the ending point side PXC via the bypass path PXC, if the failure of the current optical switch occurs in the bypass path PXC, the bypass path In the path PXC, it is determined that a device failure (failure of the optical path via the current optical switch) has occurred, and switching to the spare optical switch is performed. At this time, the PXC on the end point side determines that a transmission path failure has occurred in the transmission path via the PXC for the bypass path, and starts a transmission path switching operation by GMPLS.

  If the switching operation to the spare optical switch and the transmission path switching operation are performed at the same time, the redundant switching within the device that can be switched in a short time is performed, but the switching time is longer than the redundant switching within the device. The transmission line switching requiring is performed. As a result, switching to a path connecting the PXC on the start point side and the PXC on the end point side (a path that does not pass through the PXC 20 for the detour path) is performed. For this reason, the former and latter prior arts have a problem that failure recovery cannot be performed efficiently and quickly.

  The present invention has been made in view of the above, and an object of the present invention is to obtain an optical transmission system and an optical transmission apparatus that perform efficient and quick failure recovery.

  In order to solve the above-described problems and achieve the object, the present invention provides an optical transmission device on the optical signal start point side, an optical signal end point optical transmission device, the start point optical transmission device, and an end point side. A plurality of optical transmission lines that are redundantly connected to the optical transmission apparatus, and a communication path in the own apparatus is redundantly connected by a plurality of optical switches and is used for a detour path disposed in one of the optical transmission lines. An optical transmission device that transmits an optical signal between the optical transmission device on the start point side and the optical transmission device on the end point side through a predetermined optical path while switching the optical transmission line and the optical switch. In the system, the optical transmission device on the start point side, the optical transmission device on the end point side, and the optical transmission device for the detour path are respectively based on an input signal and an output signal of an optical path passing through the own device, Device failure of own device and transmission on the optical transmission line A failure detection unit that distinguishes and detects a failure; a device failure recovery start time that is a standby time from when the device failure is detected to when an optical switch in the device is switched to start failure recovery; and the transmission path failure A storage unit that stores a transmission line failure recovery start time that is a waiting time from when the optical transmission line is switched to when the failure recovery starts, and when the failure detection unit detects the device failure Control for performing the failure recovery after waiting for the device failure recovery start time, and for performing the failure recovery after waiting for the transmission channel failure recovery start time when the failure detection unit detects the transmission channel failure And the apparatus failure recovery start time and the transmission path failure recovery start time are set to different values according to the type of the optical path, respectively.

  According to the present invention, the standby time from when a device failure is detected until failure recovery is started and the standby time from when a transmission line failure is detected until failure recovery starts depend on the type of optical path. Since the different values are set, there is an effect that the failure recovery can be performed efficiently and quickly.

  Embodiments of an optical transmission system and an optical transmission apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment FIG. 1 is a diagram illustrating an example of a configuration of an optical transmission system according to an embodiment of the present invention. The optical transmission system 100 is a communication system (communication network) that switches an optical path to a redundantly configured optical path (optical communication path), and is a PXC (Photonic Crossconnect) that is an optical cross-connect (optical transmission apparatus). 10, 20, 30 and communication terminals 1, 2.

  The PXC 10 and the PXC 30 are redundantly connected by two transmission paths, a transmission path by direct connection and a transmission path (detour) via the PXC 20. The PXC 10 is connected to the communication terminal 1 and sends an optical signal to the PXC 30 side using the optical signal from the communication terminal 1 as an input signal. The PXC 30 is connected to the communication terminal 2 and transmits an optical signal from the PXC 10 to the communication terminal 2. In the present embodiment, the PXC 20 has an optical path (hereinafter referred to as “rerouting”) defined to establish a bypass path when a transmission path failure occurs as an optical path (optical communication path), a working path and a backup path. An optical path (hereinafter referred to as “1 + 1 protection”) through which an optical signal flows is set.

  In the optical transmission system 100, as switching of the optical communication path, each PXC 10, 20, and 30 sets / switches the optical path according to traffic demand, and transmits when a failure occurs according to the required optical path reliability. Switch the road. For control of transmission path switching in the optical transmission system 100, the GMPLS protocol of IETF is used. In this embodiment, the PXCs 10, 20, and 30 store information (switching protection time setting table 50) related to the time until the in-device redundancy switching operation and the transmission line switching operation are started, and this switching protection time setting is performed. Based on the table 50, the optical communication path is switched.

  Next, the configuration of the PXCs 10, 20, and 30 according to the embodiment will be described. Since the PXCs 10, 20, and 30 have the same configuration, the PXC 20 will be described as an example here.

  FIG. 2 is a diagram illustrating a configuration of the PXC according to the embodiment. The PXC 20 includes input side optical monitors A1 to An (n is a natural number), output side optical monitors D1 to Dn, working optical switch X1, spare optical switch X2, optical couplers B1 to Bn, output side switches C1 to Cn, and a monitoring control unit. 21 is provided. The working optical switch X1 and the standby optical switch X2 correspond to the optical switches described in the claims. The monitoring control unit 21 corresponds to a failure detection unit, a storage unit, and a control unit described in the claims.

  The input side optical monitors A1 to An are input side optical monitors that monitor input signals. The input side optical monitors A1 to An of the PXC 20 monitor input signals transmitted from an optical cross connect such as the PXC 10. In the PXC 20, any of the input side optical monitors A1 to An is connected to the PXC 10. In the following description, a case where the input side optical monitor A1 is connected to the PXC 10 will be described as an example. Each of the input side optical monitors A1 to An is connected to the optical couplers B1 to Bn on a one-to-one basis. Each of the input side optical monitors A1 to An sends an input signal to each of the optical couplers B1 to Bn.

  The optical couplers B1 to Bn are connected to both the working optical switch X1 and the standby optical switch X2, respectively. Each of the optical couplers B1 to Bn splits the input signal from the input side optical monitors A1 to An into two branches and distributes them to the working optical switch X1 and the standby optical switch X2.

  The working optical switch X1 is connected to the output side switches C1 to Cn. The working optical switch X1 is a working optical switch that switches an input signal from an arbitrary input port (optical coupler B1 to Bn side) to an arbitrary output port (output side switch C1 to Cn side).

  The spare optical switch X2 is connected to each of the output side switches C1 to Cn. The spare optical switch X2 is a spare optical switch for switching an input signal from an arbitrary input port (optical coupler B1 to Bn side) to an arbitrary output port (output side switch C1 to Cn side).

  The PXC 20 transmits an optical signal using the working optical switch X1 when performing a normal operation (a state in which no abnormality has occurred), and uses the standby optical switch X2 when the apparatus is abnormal (an abnormality of the PXC 20). Transmit optical signals.

  The output side switches C1 to Cn are 2 × 1 (2-1) switches that select one of the signal from the active optical switch X1 and the signal from the standby optical switch X2 as an output signal. Each of the output side switches C1 to Cn is connected to the output side optical monitors D1 to Dn on a one-to-one basis. Each of the output side switches C1 to Cn sends the selected output signal to the respective output side optical monitors D1 to Dn.

  The output side optical monitors D1 to Dn are output side optical monitors that monitor output signals. The output side optical monitors D1 to Dn of the PXC 20 send output signals to an optical cross connect such as the PXC 30 and monitor output signals sent to the PXC 30. In the PXC 20, any one of the output side optical monitors D1 to Dn is connected to the PXC 30. In the following description, a case where the output side optical monitor D1 is connected to the PXC 30 will be described as an example.

  The monitoring control unit 21 monitors and controls the operation of the PXC 20. The monitoring control unit 21 of the present embodiment stores a switching protection time setting table 50 that is a main feature of the present invention. Based on the switching protection time setting table 50, the supervisory control unit 21 controls switching of optical communication paths (switching of the working optical switch X1 and backup optical switch X2 and switching of transmission paths).

  Here, a connection configuration example in the case where “1 + 1 protection” in which an optical signal is sent to both the working path and the protection path is set as an optical path in the optical transmission system 100 will be described. In the PXC 20, since the input side optical monitor A1 is connected to the PXC10 and the output side optical monitor D1 is connected to the PXC30, an input signal (optical signal) from the PXC10 passes through the input side optical monitor A1 and the optical coupler B1. Are sent to the working optical switch X1 and the standby optical switch X2. Then, the optical signal from the working optical switch X1 or the standby optical switch X2 is sent to the PXC 30 via the output side switch C1 and the output side optical monitor D1.

  When “1 + 1 protection” is set in the optical transmission system 100, the PXC 10 connects, for example, the input side optical monitor A1 of the PXC 10 and the communication terminal 1, and connects the output side optical monitor D1 of the PXC 10 and the PXC 20 to each other. Keep it. In the PXC 30, for example, the input side optical monitor A1 of the PXC 30 and the PXC 20 are connected, and the output side optical monitor D1 of the PXC 30 and the communication terminal 2 are connected in advance. Further, for example, the output side optical monitor D2 of the PXC 10 and the input side optical monitor A2 of the PXC 30 are connected.

  As described above, when “1 + 1 protection” is set in the optical transmission system 100 and the PXCs 10, 20, and 30 are connected, the input signal from the PXC 20 is input to the input optical monitor A1, the optical coupler B1, and the working optical switch. The signal is input to the output side switch C1 via X1. The PXC 30 inputs an input signal from the PXC 10 to the output side switch C1 via the input side optical monitor A2, the optical coupler B2, and the standby optical switch X2. Then, the output side switch C1 sends either the optical signal from the working optical switch X1 (PXC20) or the optical signal from the standby optical switch X2 (PXC10) to the output side optical monitor D1.

  Here, the configuration of the switching protection time setting table 50 will be described. FIG. 3 is a diagram illustrating an example of the configuration of the switching protection time setting table. The switching protection time setting table 50 is information associated with “optical path type”, “apparatus failure switching protection time”, and “transmission path failure switching protection time”, and is used when switching optical communication paths. The “device failure switching protection time” corresponds to the device failure recovery start time described in the claims, and the “transmission channel failure switching protection time” corresponds to the transmission channel failure recovery start time described in the claims.

  “Optical path type” indicates the redundancy type of the optical path realized in the optical transmission system 100. “Rerouting” is an optical path (rerouting optical path) that is defined so that the start node calculates a new detour path and establishes a detour path when a transmission path failure occurs. In addition, “1 + 1 protection” is an optical path (1 + 1 protection optical path) in which optical signals are passed through both the working path and the backup path.

  The “apparatus failure switching protection time” is a time set for each type of optical path, and after the PXC 20 (monitoring control unit 21) determines that there is an apparatus failure, the redundant switching operation (apparatus PXC20) ( This is the time (standby time) until the start of the switching operation of the working optical switch X1 and the standby optical switch X2.

  The “transmission path failure switching protection time” is a time set for each type of optical path, and the transmission path switching operation (PXC10 and PXC30) after the PXC 20 (monitoring control unit 21) determines that there is a transmission path fault. This is the time (standby time) until the start of switching to direct connection or switching to detour connection.

  For example, in a path whose “optical path type” is “rerouting”, “device failure switching protection time” is RT1, and “transmission path failure switching protection time” is RT2. Further, in the path whose “optical path type” is “1 + 1 protection”, the “apparatus failure switching protection time” is PT1, and the “transmission path failure switching protection time” is PT2.

  The switching protection time setting table 50 arbitrarily sets “device failure switching protection time” and “transmission path failure switching protection time” according to the type of optical path according to an instruction from the network operator (instruction information input from the outside). It can be set / changed.

  Next, an operation procedure of the optical transmission system 100 will be described. FIG. 4 is a flowchart showing an operation procedure of the optical transmission system. FIG. 4 shows a processing flow when the monitoring control unit 21 of the PXC 20 detects an abnormality of the output side optical monitor D1.

  The PXC 20 transmits the optical signal from the PXC 10 to the PXC 30 side using the working optical switch X1. In the PXC 20, when an abnormality (light interruption) occurs in the output side optical monitor D1, the monitoring control unit 21 detects an abnormality in the output side optical monitor D1 (step S10).

  The monitoring control unit 21 confirms the output of the input side optical monitor of the optical path (the optical path corresponding to the abnormality) corresponding to the output side optical monitor D1 that detected the abnormality. Since the PXC 20 sends the optical signal from the PXC 10 to the output side optical monitor D1 via the input side optical monitor A1, the monitoring control unit 21 confirms the output of the input side optical monitor A1 (step S20).

  When the input side optical monitor A1 is abnormal (step S30, Yes), the monitoring control unit 21 has a transmission path failure upstream of the optical path (the optical path corresponding to the abnormality) of the output side optical monitor D1 that detected the abnormality. (Step S40). On the other hand, when the input side optical monitor A1 is normal (No at Step S30), the monitoring control unit 21 determines that an apparatus failure (failure of the PXC 20) has occurred (Step S80).

  When the monitoring control unit 21 determines that a transmission path failure has occurred, the monitoring control unit 21 refers to the switching protection time setting table 50 (step S50). Then, the monitoring control unit 21 extracts the “transmission path failure switching protection time” corresponding to the optical path in the abnormal state (“optical path type”) from the switching protection time setting table 50 (step S60).

  The monitoring control unit 21 of the PXC 20 performs a transmission path switching operation corresponding to the optical path corresponding to the abnormality (“optical path type”) after the “transmission path failure switching protection time” extracted from the switching protection time setting table 50 has elapsed. Then, the transmission path is switched (step S70).

  On the other hand, when the monitoring control unit 21 determines that a device failure has occurred (step S80), the monitoring control unit 21 refers to the switching protection time setting table 50 (step S90). Then, the monitoring control unit 21 extracts “apparatus failure switching protection time” corresponding to the optical path in the abnormal state (“optical path type”) from the switching protection time setting table 50 (step S100).

  The monitoring control unit 21 of the PXC 20 switches the output side switch C1 (2 × 1 switch) as a redundant switching operation in the apparatus after the “apparatus failure switching protection time” extracted from the switching protection time setting table 50 has elapsed (step S110). ). Thereby, the supervisory control unit 21 uses the input signal distributed to the standby optical switch X2 as an output signal.

  In FIG. 4, the processing flow when the monitoring control unit 21 of the PXC 20 detects an abnormality of the output side optical monitor D1 has been described. However, when the monitoring control unit 21 of the PXC 30 detects an abnormality of the output side optical monitor D1 This processing flow is the same as the processing flow described in FIG.

  Next, in the optical transmission system 100, an optical communication path switching process when a rerouting optical path is established will be described. FIG. 5 is a diagram for explaining switching processing of an optical communication path when a rerouting optical path is established. In FIG. 5, in the optical transmission system 100, when a rerouting optical path via the PXC 20 is established between the PXC 10 and the PXC 30, processing when the failure of the active optical switch X1 occurs in the PXC 20 will be described.

  In the PXC 20, based on the outputs of the output side optical monitor D1 and the input side optical monitor A1, the monitoring control unit 21 determines that a device failure has occurred in the rerouting optical path. Then, the monitoring control unit 21 of the PXC 20 obtains RT1 of “apparatus failure switching protection time” from “optical path type” (rerouting) of the switching protection time setting table 50. The supervisory control unit 21 of the PXC 20 performs the intra-device redundancy switching operation after the RT1 time obtained using the switching protection time setting table 50 has elapsed.

  In the PXC 30, based on the outputs of the output side optical monitor D1 and the input side optical monitor A1, the monitoring control unit 21 determines that a transmission path failure has occurred in the rerouting optical path. Then, the monitoring control unit 21 of the PXC 30 obtains RT2 of “transmission path failure switching protection time” from “optical path type” (rerouting) of the switching protection time setting table 50. The monitoring control unit 21 of the PXC 30 starts the transmission path switching operation of the rerouting optical path after the time RT2 obtained using the switching protection time setting table 50 has elapsed. Specifically, failure notification is performed from the PXC 30 to the PXC 10 (starting node) using an RSVP Notify message.

  In the present embodiment, the “transmission path failure switching protection time” is set longer than the “device failure switching protection time”. In other words, RT2 is set longer than RT1. For example, RT2 is set longer than the time from when a failure occurs until the PXC 20 completes the intra-device redundancy switching operation. Thereby, before the transmission line switching operation is started in the PXC 30, the intra-device redundancy switching operation is completed in the PXC 20. As a result, failure recovery (recovery) within the optical transmission system 100 can be performed by redundant switching within the apparatus with a short switching time. For this reason, the PXC 30 does not need to actually perform the transmission path switching operation of the rerouting optical path.

  Next, switching processing of the optical communication path when the 1 + 1 protection optical path is established in the optical transmission system 100 will be described. FIG. 6 is a diagram for explaining switching processing of an optical communication path when a 1 + 1 protection optical path is established. In FIG. 6, in the optical transmission system 100, when a 1 + 1 protection optical path (a path in which an optical signal flows through both the working path and the backup path) is established between the PXC 10 and the PXC 30, the working light is transmitted by the PXC 20. Processing when a failure of the switch X1 occurs will be described. The working path is an optical path between PXC 10 and PXC 30 via PXC 20, and the backup path is an optical path that directly connects PXC 10 and PXC 30.

  In the PXC 30, when performing a normal operation (a state in which no abnormality has occurred), the output side switch C1 uses the optical signal from the active optical switch X1 to transmit the optical signal from the PXC 20 to the communication terminal 2 side. .

  In the PXC 20, based on the outputs of the output side optical monitor D1 and the input side optical monitor A1, the monitoring control unit 21 determines that a device failure has occurred in the 1 + 1 protection optical path. Then, the monitoring control unit 21 of the PXC 20 obtains PT1 of “apparatus failure switching protection time” from “optical path type” (1 + 1 protection) of the switching protection time setting table 50. The monitoring control unit 21 of the PXC 20 starts the intra-device redundancy switching operation after the time PT1 obtained using the switching protection time setting table 50 has elapsed.

  In the PXC 30, based on the outputs of the output side optical monitor D1 and the input side optical monitor A1, the monitoring control unit 21 determines that a transmission path failure has occurred in the 1 + 1 protection optical path. Then, the PXC 30 monitoring control unit 21 obtains PT2 of “transmission path failure switching protection time” from “optical path type” (1 + 1 protection) of the switching protection time setting table 50. The monitoring control unit 21 of the PXC 30 starts the transmission line switching operation of the 1 + 1 protection optical path after the time PT2 obtained using the switching protection time setting table 50 has elapsed. Specifically, the monitoring control unit 21 of the PXC 30 executes the switching process of the output side switch C1 (switching from the working path to the protection path). Switching from the working path to the protection path is a switching process between the optical signal from the working optical switch X1 (PXC20) and the optical signal from the protection optical switch X2 (PXC10).

  In the present embodiment, the “device failure switching protection time” is set longer than the “transmission path failure switching protection time”. In other words, PT1 is set longer than PT2. For example, PT1 is set longer than the time from the occurrence of a failure until the transmission line switching operation is completed at the PXC 30. As a result, the transmission path switching operation (switching operation of the output side switch C1) is completed in PXC30 before the in-device redundancy switching operation is started in PXC20. As a result, it is not necessary to wait for the completion of the intra-device redundancy switching operation by the PXC 20, and the failure recovery in the optical transmission system 100 can be performed by the transmission path switching operation in the PXC 30. For this reason, the PXC 20 does not need to actually perform the intra-device redundancy switching operation.

  As described above, in the optical transmission system 100, “device failure switching protection time” and “transmission path failure switching protection time” are provided independently as protection times (waiting time) until failure recovery. Also, since the protection time is set for each type of optical path, failure recovery (intra-device redundancy switching or transmission path switching) is performed as intended by the network operator.

  In the present embodiment, the case where PXC 10 is the PXC on the start point side and PXC 30 is the PXC on the end point side has been described. Good.

  The optical transmission system 100 is not limited to the configuration illustrated in FIG. 1, and another optical transmission device (such as PXC) may be disposed between the PXC 10 and the PXC 20, for example. Further, another optical transmission device may be disposed between PXC 20 and PXC 30 or between PXC 10 and PXC 30.

  As described above, according to the first embodiment, the “device failure switching protection time” used when a failure occurs in the rerouting optical path is set to be sufficiently shorter than the “transmission path failure switching protection time”. When a device failure occurs, the failure recovery can be performed by the in-device redundancy switching operation having a shorter failure recovery time than the transmission line switching operation.

  Further, since the “transmission path failure switching protection time” used when a failure occurs in the 1 + 1 protection optical path is set sufficiently shorter than the “device failure switching protection time”, when a device failure occurs in the 1 + 1 protection optical path Thus, it is possible to perform failure recovery by the transmission path failure switching operation without waiting for completion of the in-device redundancy switching operation. Therefore, it is not necessary to perform unnecessary recovery processing among the recovery processing for the device failure and the recovery processing for the transmission path failure, so that the optical transmission system 100 can efficiently and quickly recover from the failure.

  As described above, the optical transmission system and the optical transmission apparatus according to the present invention are suitable for switching of redundantly configured optical paths.

It is a figure which shows the structure of the optical transmission system which concerns on embodiment of this invention. It is a figure which shows the structure of PXC which concerns on embodiment. It is a figure which shows an example of a structure of a switching protection time setting table. It is a flowchart which shows the operation | movement procedure of an optical transmission system. It is a figure for demonstrating the switching process of the optical communication path | route when the rerouting optical path is established. It is a figure for demonstrating the switching process of the optical communication path | route in case the 1 + 1 protection optical path is established.

Explanation of symbols

1, 2, Communication terminal 10, 20, 30 PXC
21 monitoring control unit 50 switching protection time setting table 100 optical transmission system A1 to An input side optical monitor B1 to Bn optical coupler C1 to Cn output side switch D1 to Dn output side optical monitor X1 working optical switch X2 standby optical switch

Claims (5)

An optical transmission device on the optical signal start point side, an optical signal end device optical transmission device, and a plurality of optical transmission lines that redundantly connect between the optical signal transmission device on the start point side and the optical transmission device on the end point side; The communication path in the own apparatus is redundantly connected by a plurality of optical switches and has an optical transmission device for a detour path disposed in one of the optical transmission paths, and the optical transmission path and the optical switch are switched. In an optical transmission system that transmits an optical signal between the optical transmission device on the start point side and the optical transmission device on the end point side in a predetermined optical path,
The optical transmission device on the start point side, the optical transmission device on the end point side, and the optical transmission device for the bypass path,
Based on the input signal and the output signal of the optical path passing through the own device, a failure detecting unit that distinguishes and detects the device failure of the own device and the transmission path failure on the optical transmission path,
After detecting the device failure recovery start time and the transmission line failure, which is a waiting time from the detection of the device failure to switching the optical switch in the device and starting the failure recovery, the optical transmission line is switched and the failure is detected. A storage unit for storing a transmission path failure recovery start time, which is a waiting time until recovery starts,
When the failure detection unit detects the device failure, the failure detection unit waits for the device failure recovery start time and then performs the failure recovery. When the failure detection unit detects the transmission channel failure, the transmission line failure recovery is performed. A control unit for performing the failure recovery after waiting for a start time;
With
The apparatus failure recovery start time and the transmission path failure recovery start time are set to different values according to the type of the optical path, respectively. The type of the optical path is a rerouting optical path that is set so as to calculate the detour path in which the start-side node avoids the position of the failure when the transmission path failure occurs and to establish the calculated detour path,
The optical transmission system according to claim 1, wherein the device failure recovery start time corresponding to the rerouting optical path is shorter than a transmission path failure recovery start time corresponding to the rerouting optical path. The type of the optical path is a 1 + 1 protection optical path that transmits an optical signal to both an active optical transmission line and a backup optical transmission line among the optical transmission lines,
3. The optical transmission system according to claim 1, wherein the transmission path failure recovery start time corresponding to the 1 + 1 protection is shorter than a device failure recovery start time corresponding to the 1 + 1 protection. The device failure recovery start time and / or the transmission line failure recovery start time is:
The optical transmission system according to any one of claims 1 to 3, wherein the information is set and changed based on an externally input instruction. In a network in which a plurality of optical transmission lines and a plurality of optical switches are redundantly connected, an optical transmission apparatus that transmits an optical signal through a predetermined optical path while switching the optical transmission line and the optical switch,
Based on the input signal and the output signal of the optical path passing through the own device, a failure detecting unit that distinguishes and detects the device failure of the own device and the transmission path failure on the optical transmission path,
After detecting the device failure recovery start time and the transmission line failure, which is a waiting time from the detection of the device failure to switching the optical switch in the device and starting the failure recovery, the optical transmission line is switched and the failure is detected. A storage unit for storing a transmission path failure recovery start time, which is a waiting time until recovery starts,
When the failure detection unit detects the device failure, the failure detection unit waits for the device failure recovery start time and then performs the failure recovery. When the failure detection unit detects the transmission channel failure, the transmission line failure recovery is performed. A control unit for performing the failure recovery after waiting for a start time;
With
The apparatus failure recovery start time and the transmission path failure recovery start time are set to different values according to the type of the optical path, respectively.

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