Optical communication system, SNCP switching method and related equipment

Abstract

The invention provides an optical communication system which is applied to the field of optical communication. The optical communication system comprises a first CPE, a first node, a second node and a second CPE. The first CPE is used for transmitting the first service signal to the first node. The first node is used for transmitting the first service signal to the second node through the first main service channel and the first standby service channel. The first main service channel is carried by the first service channel. The first standby service channel is carried by the second service channel. The first service channel and the second service channel are corresponding SNCP protection groups. And the second CPE and the second node are connected through the second main service channel and the second standby service channel. And if the PM fault is detected, the second CPE is used for switching, and the first service signal is received through the second standby service channel. In the scheme, the second node establishes the protection group of the high-order channel, and the switching corresponding to the alarm of the low-order channel is allocated to the second CPE, so that the switching frequency of the second node can be reduced, and the switching efficiency is improved.

Description

Technical Field

[0001] The present application relates to the field of optical communications, and in particular to an optical communication system, a subnetwork connection protection (SNCP) switching method, and related equipment. Background Art

[0002] In the SNCP protection mechanism, the transmission path for service signals is divided into a working path and a protection path. The source end transmits service signals through the working path and protection path respectively. The sink end selects and receives service signals. When the working path is fault-free, the sink end selects to receive service signals from the working path. When the working path is interrupted or the transmitted service signal degrades to a certain extent, the sink end switches the receiving path and receives service signals through the protection path. In a network where a high-order channel carries a low-order channel, an SNCP protection group corresponding to the low-order channel can be established. For example, in a network where an optical data unit (ODU) channel carries an OSU channel, a protection group can be established at the source end for each OSU channel in the ODU channel. A protection group consists of a working path and a protection path. An ODU2 channel may include 4000 optical service unit (OSU) channels. 4000 OSU channels correspond to 4000 protection groups. When an ODU2 channel fails, all 4000 protection groups will be switched simultaneously, reducing switching efficiency. Summary of the Invention

[0003] The present application provides an optical communication system, an SNCP switching method and related equipment, which can reduce the number of times the second node needs to switch and improve the switching efficiency by allocating the switching corresponding to the alarm of the low-order channel to the edge node.

[0004] The first aspect of the present application provides an optical communication system. The optical communication system includes a first customer premises equipment (CPE), a first node, a second node, and a second CPE. The first CPE, the first node, the second node, and the second CPE may be optical transport network (OTN) devices or metro transport network (MTN) devices, etc. The first CPE is used to transmit a first service signal to the first node. The first node is used to transmit the first service signal to the second node through a first primary service channel and a first standby service channel respectively. The first primary service channel is carried on a first service channel. The first standby service channel is carried on a second service channel. The service channel is a high-order channel and is used to carry the service channel. For example, the service channel may be an ODU channel, an optical transport unit (OTU) channel, an optical payload unit (OPU) channel, a flexible OTN channel, a virtual container (VC) 4 channel, or an MTN channel, etc. The service channel may be a low-order channel such as an OSU channel or a VC12 channel relative to the high-order channel. For example, the service channel is an ODU channel and the service channel is an OSU channel. Another example is that the service channel is a VC4 channel and the service channel is a VC12 channel. The first service channel and the second service channel are corresponding SNCP protection groups. The second node is used to receive the first service signal through the first service channel. When the first service channel fails, the second node is used to receive the first service signal through the second service channel. The second node and the second CPE are connected through a second primary service channel and a second standby service channel. The second node is used to transmit the first service signal to the second CPE through the second primary service channel and the second standby service channel. The second primary service channel and the second standby service channel are corresponding SNCP protection groups. Under normal circumstances, the second CPE is used to receive the first service signal from the second node through the second primary service channel. If the first condition is met, the second CPE is used to perform a switchover and receive the first service signal through the second standby service channel. The first condition includes that the second CPE detects a path monitoring (PM) failure.

[0005] In this application, the first node and the second node may also be referred to as intermediate nodes, and the first CPE and the second CPE may also be referred to as edge nodes. A failure in the first main service channel can be transmitted to the second CPE via a PM failure. The second CPE performs switching based on the PM failure, thereby ensuring normal transmission of service signals. Therefore, the intermediate node does not need to perform switching based on the failure of the first main service channel. By allocating the switching corresponding to alarms on low-order channels to the edge nodes, the number of switching required by the intermediate node can be reduced, improving switching efficiency. In addition, the first service channel and the second service channel form corresponding SNCP protection groups. When the first service channel fails, the second node can transmit the first service signal via the second service channel. The service channel includes multiple service channels. Switching multiple service channels by switching the service channel can improve switching efficiency.

[0006] In an optional manner of the first aspect, the second backup service channel is connected to the first backup service channel. By connecting the second backup service channel to the first backup service channel, the number of backup service channels can be reduced, thereby saving transmission resources.

[0007] In an optional manner of the first aspect, the first node is also used to transmit the first service signal to the second node through the third main service channel in the third service channel and the third backup service channel in the fourth service channel, respectively. The third service channel and the fourth service channel are connected to the second backup service channel and the third main service channel of the corresponding SNCP protection group. In the present application, two pairs of protection groups are established between the first node and the second node, and the two pairs of protection groups correspond one-to-one to the two service channels of the next-level node (the second main service channel and the second backup service channel). When the first service channel and the second service channel fail, the first node can transmit the first service signal to the second node through the third service channel and the fourth service channel. Therefore, the present application can improve the anti-interference capability of the transmission service.

[0008] In an optional manner of the first aspect, the first condition also includes: after a PM fault is detected, the PM fault is not eliminated after a first defect confirmation time has passed. In actual applications, a high-order channel fault may also be transmitted to the second CPE through a PM fault. The central node can perform switching through a TCM fault, thereby eliminating the high-order channel fault. After the central node eliminates the high-order channel fault, the PM fault will also be eliminated. Therefore, the present application can reduce the probability of repeated switching between the central node and the edge node due to a single fault. Repeated switching not only consumes processing resources, but may also increase the duration of service interruption, thereby affecting user experience. Therefore, the present application can save processing resources and improve user experience.

[0009] In an alternative embodiment of the first aspect, the duration for the second node to switch the channel for receiving the first service signal from the first service channel to the second service channel is the first switching duration. The first defect confirmation time is greater than the first switching duration. By controlling the duration of the first defect confirmation time, the probability of repeated switching by the central node and the edge node due to a single fault can be reduced. Repeated switching not only consumes processing resources but also may increase the duration of service interruption, thus affecting the user experience. Therefore, the present application can save processing resources and improve the user experience.

[0010] In an alternative embodiment of the first aspect, a < T ≤ b - a. Wherein, T is the first defect confirmation time. a is the first switching duration, and the value range of b is between 40 milliseconds and 60 milliseconds. b ≥ 2a. By controlling the value of b, it is possible to prevent the first defect confirmation time from being too large, thereby affecting the duration of service interruption. Therefore, the present application can improve the user experience.

[0011] In an alternative embodiment of the first aspect, if the second CPE detects a tandem connection monitoring (TCM) fault, the second CPE is used to receive the first service signal through the second standby service channel. If the second CPE detects a TCM fault in the second standby service channel, it indicates that the second CPE may not be able to receive the first service signal through the second standby service channel. Through switching, the present application can increase the probability of normally receiving the service signal, thereby improving the user experience.

[0012] In an alternative embodiment of the first aspect, there is no corresponding defect confirmation time for the TCM fault, that is, the defect confirmation time corresponding to the TCM fault is 0. By immediately performing switching after detecting the TCM fault, the duration of service interruption can be reduced, thereby improving the user experience.

[0013] In an alternative embodiment of the first aspect, the second CPE is further used to receive a first automatic protection switching (APS) message from the second node. The first APS message includes information about the TCM fault. The second CPE is further used to receive a second APS message from the first CPE. The second APS message includes information about the PM fault. In practical applications, communication is two-way. By synchronizing the fault detected in one transmission direction to the communication node in the other transmission direction through the APS message, the efficiency of fault determination can be improved, thereby reducing the duration of service interruption and improving the user experience.

[0014] In an alternative manner of the first aspect, the second node is a core node, the first node is a first aggregation node, and the communication system further includes a first central office, a second central office, and a second aggregation node. The first CPE is configured to transmit a first service signal to the second CPE sequentially through the first central office, the first aggregation node, the core node, the second aggregation node, and the second central office.

[0015] A second aspect of the present application provides an SNCP switching method. The SNCP switching method is applied to a central node, such as the second node. The SNCP switching method includes the following steps: The second node receives a first service signal from the first node through a first primary service channel. The first primary service channel is carried on a first service channel. The first service channel and the second service channel form a corresponding SNCP protection group. The second node and the second CPE are connected through a second primary service channel and a second standby service channel. The second node does not perform switching based on the fault information of the first primary service channel. The second node transmits the first service signal to the second CPE through the second primary service channel and the second standby service channel respectively. The second CPE is configured to switch the channel for receiving the first service signal according to the PM fault.

[0016] In an alternative manner of the second aspect, the SNCP switching method further includes the following steps: The second node sends a first APS message to the second CPE. The first APS message includes information about the TCM fault. The information about the TCM fault is used for the second CPE to switch the channel for receiving the first service signal according to the TCM fault.

[0017] A third aspect of the present application provides an SNCP switching method. The SNCP switching method is applied to an edge node, such as the second CPE. The SNCP switching method includes the following steps: The second CPE receives a first service signal from the second node through a second primary service channel. The second node is configured to receive the first service signal from the first node through a first primary service channel. The first primary service channel is carried on a first service channel. The first service channel and the second service channel form a corresponding SNCP protection group. If a first condition is satisfied, the second CPE performs switching and receives the first service signal through the second standby service channel. The first condition includes that the second CPE detects a PM fault.

[0018] In an alternative manner of the third aspect, the second standby service channel is connected to the first standby service channel.

[0019] In an alternative manner of the third aspect, the first node is configured to transmit the first service signal to the second node through a third primary service channel in a third service channel and a third standby service channel in a fourth service channel respectively. The third primary service channel and the third standby service channel form a corresponding SNCP protection group. The second standby service channel is connected to the third primary service channel.

[0020] In an alternative manner of the third aspect, the first condition further includes: after detecting a PM fault and after a first defect confirmation time, the PM fault has not been eliminated.

[0021] In an alternative manner of the third aspect, the SNCP switching method further includes the following steps: If the second CPE detects a TCM fault, the second CPE receives the first service signal through the second primary service channel.

[0022] In an alternative manner of the third aspect, there is no corresponding defect confirmation time for a TCM fault.

[0023] In an alternative manner of the third aspect, the SNCP switching method further includes the following steps: The second CPE receives a first APS message from the second node. The first APS message includes information about the TCM fault. The second CPE receives a second APS message from the first CPE. The second APS message includes information about the PM fault.

[0024] A second node is provided in the fourth aspect of the present application. The second node includes a receiving unit and a transmitting unit. The receiving unit is configured to receive the service signal of the first customer premise equipment (CPE) from the first node through the first primary service channel. The first primary service channel is carried on the first service channel. The first service channel and the second service channel form a corresponding SNCP protection group. The second node does not perform switching based on the fault information of the first primary service channel. The transmitting unit is configured to transmit the first service signal to the second CPE through the second primary service channel and the second standby service channel respectively. The second CPE is configured to switch the channel for receiving the first service signal according to the PM fault.

[0025] A second CPE is provided in the fifth aspect of the present application. The second CPE includes a receiving unit and a processing unit. The receiving unit is configured to receive the first service signal from the second node through the second primary service channel. The second node is configured to receive the first service signal from the first node through the first primary service channel. The first primary service channel is carried on the first service channel. The first service channel and the second service channel form a corresponding SNCP protection group. The processing unit is configured to determine whether a PM fault is detected. If the first condition is satisfied, the receiving unit is configured to perform switching and receive the first service signal through the second standby service channel. The first condition includes that the processing unit detects a PM fault.

[0026] The sixth aspect of the present application provides a second node. The second node includes a receiver and a transmitter. The receiver is configured to receive the service signal of the first customer premise equipment (CPE) from the first node through a first primary service channel. The first primary service channel is carried on a first service channel. The first service channel and the second service channel form a corresponding SNCP protection group. The second node does not perform switching based on the fault information of the first primary service channel. The transmitter transmits the first service signal to the second CPE through a second primary service channel and a second standby service channel respectively. The second CPE is configured to switch the channel for receiving the first service signal according to the PM fault.

[0027] The seventh aspect of the present application provides a second CPE. The second CPE includes a receiver and a processor. The receiver is configured to receive the first service signal from the second node through a second primary service channel. The second node is configured to receive the first service signal from the first node through a first primary service channel. The first primary service channel is carried on a first service channel. The first service channel and the second service channel form a corresponding SNCP protection group. The processor is configured to determine whether a PM fault is detected. If a first condition is satisfied, the transmitter is configured to perform switching and receive the first service signal through a second standby service channel. The first condition includes that the processor detects a PM fault.

[0028] It should be understood that there are similarities between the SNCP switching method described in the second aspect or any optional manner of the second aspect, the second node described in the fourth aspect or the sixth aspect, and the optical communication system described in the first aspect or any optional manner of the first aspect. Therefore, regarding the SNCP switching method described in the second aspect or any optional manner of the second aspect, and the second node described in the fourth aspect or the sixth aspect, reference can be made to the optical communication system described in the first aspect or any optional manner of the first aspect. Similarly, there are similarities between the SNCP switching method described in the third aspect or any optional manner of the third aspect, the second CPE described in the fifth aspect or the seventh aspect, and the optical communication system described in the first aspect or any optional manner of the first aspect. Therefore, regarding the SNCP switching method described in the third aspect or any optional manner of the third aspect, and the second CPE described in the fifth aspect or the seventh aspect, reference can be made to the optical communication system described in the first aspect or any optional manner of the first aspect.

[0029] The eighth aspect of the present application provides a processing chip. The processing chip includes a processing circuit, and the processing circuit is configured to execute the SNCP switching method described in the second aspect, any optional manner of the second aspect, the third aspect, or any optional manner of the third aspect.

[0030] The ninth aspect of the present application provides a computer-readable storage medium storing instructions, which, when executed by a computer, implement the SNCP switching method described in the foregoing second aspect, any optional manner of the second aspect, the third aspect, or any optional manner of the third aspect.

[0031] The tenth aspect of the present application provides a computer program product including instructions, which, when running on a computer, cause the computer to execute the SNCP switching method described in the foregoing second aspect, any optional manner of the second aspect, the third aspect, or any optional manner of the third aspect.

[0032] Among them, the technical effects brought by any optional manner in the second aspect to the tenth aspect can be referred to the technical effects brought by the foregoing first aspect and different optional manners in the first aspect, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1a It is the first structural schematic diagram of the optical communication system provided by the embodiment of the present application;

[0034] Figure 1b It is the second structural schematic diagram of the optical communication system provided by the embodiment of the present application;

[0035] Figure 2 It is the third structural schematic diagram of the optical communication system provided by the embodiment of the present application;

[0036] Figure 3 It is the fourth structural schematic diagram of the optical communication system provided by the embodiment of the present application;

[0037] Figure 4 It is the fifth structural schematic diagram of the optical communication system provided by the embodiment of the present application;

[0038] Figure 5 It is the sixth structural schematic diagram of the optical communication system provided by the embodiment of the present application;

[0039] Figure 6 It is the seventh structural schematic diagram of the optical communication system provided by the embodiment of the present application;

[0040] Figure 7 It is the first flow schematic diagram of the SNCP switching method provided by the embodiment of the present application;

[0041] Figure 8 It is the second flow schematic diagram of the SNCP switching method provided by the embodiment of the present application;

[0042] Figure 9 It is the first structural schematic diagram of the second node provided by the embodiment of the present application;

[0043] Figure 10 A first structural diagram of the second CPE provided in an embodiment of the present application;

[0044] Figure 11 A second structural diagram of the second node provided in an embodiment of the present application;

[0045] Figure 12 This is a second structural diagram of the second CPE provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] The present application provides an optical communication system, an SNCP switching method, and related equipment. By allocating the switching corresponding to the alarm of the low-order channel to the edge node, the number of times the second node needs to switch can be reduced, thereby improving the efficiency of the switching. It should be understood that the "first", "second", etc. used in this application are only used for the purpose of distinguishing the description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying the order. In addition, for the sake of simplicity and clarity, reference numbers and / or letters are repeated in multiple figures of this application. Repetition does not indicate a strict limit relationship between various embodiments and / or configurations.

[0047] The technical solutions in this application will be described below in conjunction with the accompanying drawings. Based on this application, all other solutions obtained by those skilled in the art without creative work are within the scope of protection of this application. First, some of the terms in this application are explained to facilitate understanding by those skilled in the art.

[0048] 1. Subnetwork Connection Protection (SNCP): A service transmission protection method that establishes an SNCP protection group between two communication nodes. The SNCP protection group consists of a corresponding working path and a protection path. The source end of each communication node transmits service signals over the working path and the protection path, respectively. When the working path is normal, the sink end receives service signals over the working path. If the working path is interrupted or the transmitted service signal degrades to a certain extent, the sink end switches to receiving the service signal over the protection path.

[0049] 2. Tandem Connection Monitoring (TCM) Overhead: It is part of the general overhead and is used to record the monitoring information of the TCM layer for a segment of the entire path. The TCM overhead includes one or more sub-TCMs. For example, multiple sub-TCMs include TCM1 and TCM2. TCM1 is used for transmission channel error monitoring and frame synchronization signals. TCM2 is used for transmitting partial cross-overhead and section monitoring port information. A communication node can determine whether there is a TCM fault between it and the upper-level communication node through the TCM overhead. For a TCM fault caused by a working path, the communication node can eliminate the TCM fault by switching the receiving path. Each time a communication node is passed through, the communication node generates new TCM layer monitoring information. Therefore, the next-level communication node of a communication node will not perceive whether a TCM fault has occurred between the communication node and its upper-level communication node.

[0050] 3. Path Monitoring (PM) Overhead: It is part of the general overhead and is used to record the monitoring information of the PM layer for the entire path. A communication node can determine whether a PM fault has occurred in the transmission path before the communication node through the PM overhead. The communication node will pass the PM layer monitoring information to the next-level communication node. Therefore, when the entire transmission path includes multiple segments of transmission paths, the PM overhead is used to monitor the fault information of the entire transmission path, and the TCM overhead is used to monitor the fault information of a certain segment of the transmission path.

[0051] Embodiments of this application are applicable to optical networks such as optical transport networks or metropolitan area transport networks. The optical transport network includes OTN or flexible ethernet (FlexE). In the subsequent description of this application, OTN will be used as an example for description. An OTN usually consists of multiple OTN devices connected by optical fibers and can be configured into different topological types such as linear, ring, and mesh according to specific needs. According to actual requirements, an OTN device may have different functions. Generally, OTN devices are divided into optical layer devices, electrical layer devices, and optoelectronic hybrid devices. Optical layer devices refer to devices that can process optical layer signals, such as optical amplifiers (OAs) and optical add-drop multiplexers (OADMs). The OA is mainly used to amplify optical signals to support longer-distance transmission while ensuring specific performance of the optical signals. The OADM is used to perform spatial transformation on optical signals so that they can be output from different output ports (also known as directions). Electrical layer devices refer to devices that can process electrical layer signals, such as devices that can process OTN signals. Optoelectronic hybrid devices refer to devices that have the ability to process both optical layer signals and electrical layer signals. It should be noted that according to specific integration requirements, an OTN device can integrate multiple different functions. The technical solution provided in this application is applicable to OTN devices with electrical layer functions in different forms and integration levels.

[0052] It should be noted that the data frame structure used by the OTN device in the embodiments of this application can be an OTN frame, which is used to carry various service data and provide rich management and monitoring functions. The OTN frame can be an optical payload unit (OPU), an optical data unit (ODU), an optical transport unit (OTU), a Flexible OTN (FlexO) frame, etc. The OPU includes OPUk, OPUCn, and OPUflex, the ODU includes ODUk, ODUCn, and ODUflex, and the OTU includes OTUk and OTUCn. Among them, the OTU frame includes the ODU frame and OTU overhead, and the ODU frame includes the OPU frame and ODU overhead. k represents different rate levels. For example, k = 1 represents 2.5 Gbps, and k = 4 represents 100 Gbps. Cn represents a variable rate, specifically a rate that is a positive integer multiple of 100 Gbps. Flex means flexible. It should also be pointed out that with the development of optical transport network technology, new types of OTN frames may be defined and are also applicable to this application. For example, the OTN frame can also include an fgOTN frame (including fgODUflex and fgOPUflex) or an optical service unit (OSU) frame. In addition, the method disclosed in this application can also be applicable to other optical transport network frames such as FlexE frames. In practical applications, multiple lower-order channels can be carried between two communication nodes through a higher-order channel. For example, an OSU channel is carried through an ODU channel. The higher-order channel is also called a service channel, and the lower-order channel is also called a traffic channel. The object of the SNCP protection group can be a higher-order channel or a lower-order channel. Descriptions will be given separately below.

[0053] When the object of the SNCP protection group is a higher-order channel, if the working path of the higher-order channel fails, the communication node will switch the working path of the higher-order channel to the protection path of the higher-order channel. At this time, when a certain lower-order channel fails, the communication node cannot be triggered to switch, resulting in service interruption and reducing the impact on users.

[0054] When the object of the SNCP protection group is a low-order channel, if the working path of the low-order channel fails, the communication node will switch the working path of the low-order channel to the protection path of the low-order channel. In practical applications, there may be a huge number of low-order channels between two communication nodes. For example, one ODU2 channel may include 4000 OSU channels. 4000 OSU channels correspond to 4000 protection groups. A failure of a high-order channel will cause a failure of the low-order channel. Therefore, when the ODU2 channel fails, all 4000 OSU channels will fail. At this time, the communication node needs to perform switching on 4000 protection groups, thereby reducing the switching efficiency.

[0055] To this end, the present application provides an optical communication system. Figure 1a FIG. is a first structural schematic diagram of the optical communication system provided by the embodiment of the present application. As Figure 1a shown, the optical communication system includes 4 communication nodes. The communication node can be an OTN device or a metro transport network (MTN) device, etc. The 4 communication nodes include a first CPE 101, a first node 102, a second node 103, and a second CPE 104. In the optical communication system, the node located at the edge position of the transmission path is also called an edge node, and the node located at the non-edge position of the transmission path is also called a central node. In Figure 1a the example, the first CPE 101 and the second CPE 104 are edge nodes, and the first node 102 and the second node 103 are central nodes.

[0056] It should be understood that in Figure 1a the example, the optical communication system includes 4 series-connected communication nodes. In practical applications, the optical communication system may include more series-connected communication nodes. Similarly, in Figure 1a the example, one central node is connected to one edge node. In practical applications, one central node can be connected to multiple edge nodes. Similarly, in Figure 1a the example, one central node is connected to one central node. In practical applications, one central node can be connected to multiple central nodes. To sum up, Figure 1a this is only an example of the optical communication system provided by the embodiment of the present application. In practical applications, those skilled in the art can network multiple communication nodes according to requirements to obtain an optical communication system with different topological structures.

[0057] In Figure 1a the example, the first CPE 101 is used to send a first service signal to the second CPE 104 through the first node 102 and the second node 103. The process of the optical communication system transmitting the first service signal will be described below.

[0058] A first SNCP protection group is established between the first CPE 101 and the first node 102. The working path of the first SNCP protection group is A1, and the protection path of the first SNCP protection group is A2. The object of the first SNCP protection group is a low-order channel. To avoid the failure of a high-order channel causing the simultaneous failure of the working path and the protection path, A1 and A2 can belong to different high-order channels. The first CPE 101 transmits the first service signal to the first node 102 through the working path and the protection path respectively. The first service signal is an optical signal. The transmission path between the first CPE 101 and the first node 102 is called the first transmission path. The first CPE 101 is used to send TCM overhead and PM overhead to the first node 102. The TCM overhead is used to monitor whether there is a fault in the first transmission path. The PM overhead is used to monitor whether there is a fault in the transmission path before the first node 102.

[0059] The first node 102 determines whether there is a fault in the working path of the first SNCP protection group. For example, the first node 102 determines whether there is a fault in the working path through the TCM overhead. When the first node 102 determines that A1 is free of faults through determination, the first node 102 receives the first service signal through A1. When the first node 102 determines that A1 has a fault through determination, the first node 102 receives the first service signal through A2. For example, the first node 102 includes a controller 1 and a controller 2. The first node 102 is used to transmit the first service signal to the controller 1 and the controller 2 respectively. The controller 1 and the controller 2 can be an optical switch, an electrical switch, a service cross-connect chip, etc. It should be understood that a communication node can perform optoelectronic conversion on the received optical signal to obtain an electrical signal, and then convert the electrical signal into an optical signal. The present application does not elaborate on the specific processing process of the communication node for the first service signal. When the working path of the first SNCP protection group is free of faults, the controller 1 and the controller 2 select to receive the first service signal from A1. When the working path of the first SNCP protection group fails, the controller 1 and the controller 2 switch the receiving path and select to receive the first service signal from A2. The controller 1 is connected to B1. The controller 2 is connected to B2. The controller 1 and the controller 2 are used to output the first service signal respectively. It should be understood that an intermediate node can modify the received first service signal, such as replacing the TCM overhead, etc. Therefore, the first service signal received by the first node 102 and the first service signal output by the first node 102 may be different.

[0060] A second SNCP protection group is established between the first node 102 and the second node 103. The working path of the second SNCP protection group is the first service channel, and the protection path of the second SNCP protection group is the second service channel. The object of the second SNCP protection group is the high-order channel. The first node 102 is used to transmit the first service signal to the second node 103 through the first primary service channel (B1) and the first standby service channel (B2) respectively. The first primary service channel is carried on the first service channel. The first standby service channel is carried on the second service channel. The first node 102 sends TCM overhead and PM overhead to the second node 103. The transmission path between the first node 102 and the second node 103 is called the second transmission path. The TCM overhead is used to monitor whether there is a fault in the second transmission path. The PM overhead is used to monitor whether there is a fault in the transmission path before the second node 103.

[0061] The second node 103 determines whether there is a fault in the working path of the second SNCP protection group. When the second node 103 determines that the first service channel is fault-free, the second node 103 does not perform a switchover and receives the first service signal through the first service channel. When the second node 103 determines that the first service channel has a fault, the second node 103 switches the receiving path and receives the first service signal through the second service channel. For example, the second node 103 includes a controller 3 and a controller 4. The second node 103 is used to transmit the first service signal to the controller 3 and the controller 4 respectively. The controller 3 and the controller 4 are used to select and receive the first service signal from B1 or B2. When the first service channel is fault-free, the controller 3 receives the first service signal through B1, and the controller 4 receives the first service signal through B2. When the first service channel fails, the controller 3 switches the receiving path, the controller 3 receives the first service signal through B2, and the controller 4 receives the first service signal through B2. The controller 3 is connected to C1. The controller 4 is connected to C2. The controller 3 and the controller 4 are used to output the first service signal respectively.

[0062] In Figure 1a the example, a high-order SNCP protection group of the first service channel and the second service channel is established between the second node 103 and the first node 102. In practical applications, the first service channel may include multiple low-order channels. The multiple low-order channels in the first service channel and the multiple low-order channels in the second service channel are in one-to-one correspondence. A low-order SNCP protection group can be established for two corresponding low-order channels. The multiple low-order channels and the multiple low-order SNCP protection groups are in one-to-one correspondence. When the first service channel fails, the first service channel is switched to the second service channel. Therefore, by switching the service channel, multiple service channels can be switched, which can improve the switching efficiency.

[0063] A third SNCP protection group is established between the second node 103 and the second CPE 104. The working path of the third SNCP protection group is C1, and the protection path of the third SNCP protection group is C2. The object of the third SNCP protection group is the low-order channel. To avoid the failure of a high-order channel causing the simultaneous failure of the working path and the protection path, C1 and C2 can belong to different high-order channels. The second node 103 transmits the first service signal to the second CPE 104 through C1 and C2 respectively. The transmission path between the second node 103 and the second CPE 104 is called the third transmission path. The second node 103 sends TCM overhead and PM overhead to the second CPE 104. The TCM overhead is used to monitor whether there is a failure in the third transmission path. The PM overhead is used to monitor whether there is a failure in the transmission path before the second CPE 104.

[0064] The second CPE 104 determines whether there is a failure in the transmission path before the second CPE 104. For example, when a B1 transmission failure occurs, the second node 103 will write the failure information into the PM overhead. When the second CPE 104 determines through the PM overhead that there is no failure in the transmission path before the second CPE 104, the second CPE 104 receives the first service signal through C1. When the first condition is met, the second CPE 104 switches the receiving path and receives the first service signal through C2. The first condition includes: the second CPE 104 determines that there is a failure in the transmission path before the second CPE 104 (i.e., the second CPE 104 detects a PM failure). For example, the second CPE 104 includes a controller 21. When the second CPE 104 determines through the PM overhead that there is no failure in the transmission path before the second CPE 104, the controller 21 selects to receive the first service signal from C1. When the second CPE 104 determines through the PM overhead that there is a failure in the transmission path before the second CPE 104, the controller 21 switches the receiving path and selects to receive the first service signal from C2. According to the foregoing description, C2 is connected to the controller 4. The controller 4 is used to receive the first service signal from B2. Therefore, by switching the third SNCP protection group, the impact caused by the B1 failure can be eliminated.

[0065] In the embodiment of the present application, the central node does not perform switching according to the failure of the low-order channel. The central node transfers the failure of the low-order channel to the edge node through the PM overhead. For example, in Figure 1aIn the example, when B1 fails, the second node 103 does not switch according to the fault information of B1, but transmits the fault information to the second CPE 104 through the PM overhead. The edge node switches according to the fault information of the PM overhead. After the second CPE 104 switches, C2 connected to other service channels, such as the first backup service channel. Therefore, in the embodiment of the present application, the central node can reduce the number of times the intermediate nodes need to switch by allocating the switching corresponding to the alarm of the low-order channel to the edge node, thereby improving the switching efficiency. In addition, the first service channel and the second service channel are corresponding SNCP protection groups. Therefore, when the first service channel fails, the second node can transmit the first service signal through the second service channel. The service channel includes multiple service channels. Switching multiple service channels by switching the service channel can improve the switching efficiency.

[0066] exist Figure 1a In the example, the second CPE 104 can also determine whether there is a fault in the third transmission path. For example, the second CPE 104 receives the first service signal through C1. The second CPE 104 determines whether there is a fault in C1 based on the TCM overhead. When the second CPE 104 determines that there is no fault in C1, the second CPE 104 receives the first service signal through C1. When the second CPE 104 determines that there is a fault in C1 (i.e., when the second CPE 104 detects a TCM fault), the second CPE 104 switches and receives the first service signal through C2. For another example, the second CPE 104 receives the first service signal through C2. The second CPE 104 determines whether there is a fault in C2. When the second CPE 104 determines that there is no fault in C2, the second CPE 104 receives the first service signal through C2. When the second CPE 104 determines that there is a fault in C2, the second CPE 104 switches and receives the first service signal through C1.

[0067] according to Figure 1a As can be seen from the description, when the first condition is met, the second CPE 104 switches the receiving path and receives the first service signal through C2. In actual applications, if the first service channel fails, the second node 103 may also transmit the fault information through the PM overhead. Figure 1a As can be seen from the description, if a fault occurs in the first service channel, second node 103 is used to perform switching based on the fault information, thereby ensuring normal transmission of service signals. Therefore, second CPE 104 and second node 103 may repeatedly switch due to a single fault. Repeated switching not only consumes processing resources but also may increase service interruption duration, thereby affecting user experience.

[0068] For this reason, the first condition may further include that after detecting a PM fault and after a first defect confirmation time, the PM fault has not been eliminated. If the fault information in the PM overhead is the fault information in the first service channel, the second node 103 will perform a switchover according to the fault information. After the switchover, if the second node 10 can normally receive the first service signal through the second service channel, the PM fault will be eliminated. Therefore, by increasing the first defect confirmation time, the second CPE 104 can determine whether the PM fault belongs to the fault information of the first service channel or the fault information of B1. If the PM fault is eliminated after the first defect confirmation time, it indicates that the PM fault belongs to the fault information of the first service channel. At this time, the second CPE 104 does not need to perform a switchover according to the PM fault. If the PM fault has not been eliminated after the first defect confirmation time, it indicates that the PM fault belongs to the fault information of B1. At this time, the second CPE 104 performs a switchover according to the PM fault.

[0069] According to Figure 1a the description, if there is a fault in the first service channel, the second node 103 is used to perform a switchover according to the fault information. The time duration for the second node 103 to switch the channel for receiving the first service signal from the first service channel to the second service channel is the first switching duration. For example, the first switching duration is 20 milliseconds, 25 milliseconds, or 30 milliseconds. In practical applications, in order to reduce the probability of repeated switchovers of the central node and the edge node due to a single fault, the first defect confirmation duration is greater than the first switching duration.

[0070] According to Figure 1a the description, when the PM fault is the fault information of B1, the second node 103 will not perform a switchover according to the fault information of B1. Therefore, within the first defect confirmation time, the optical communication system cannot normally transmit the first service signal. If the first defect confirmation duration is too long, the duration of service interruption will be too long, thus affecting the user experience. For this reason, in the embodiments of the present application, the first defect confirmation duration can be less than or equal to a target threshold, that is, T ≤ b - a. Where T is the first defect confirmation time. b - a is the target threshold. a is the first switching duration. The value range of b is between 40 milliseconds and 60 milliseconds. b ≥ 2a.

[0071] As described above Figure 1a the description, when the second CPE 104 detects a TCM fault, the second CPE 104 performs a switchover. The TCM overhead detected by the second CPE 104 is used to characterize whether there is a fault in the third transmission path. The time duration for eliminating the TCM fault directly affects the duration of service interruption. Therefore, the TCM fault may not have a corresponding defect confirmation time, that is, the defect confirmation time corresponding to the TCM fault is 0. After detecting the TCM fault, the second CPE 104 does not need to wait for the corresponding defect confirmation time, but directly performs a switchover.

[0072] In the foregoing Figure 1a example, the first CPE 101 sends a first service signal to the second CPE 104 via the first node 102 and the second node 103. In practical applications, the second CPE 104 can also send a second service signal to the first CPE 101 via the second node 103 and the first node 102. Figure 1b This is the second schematic structural diagram of the optical communication system provided by the embodiment of the present application. In Figure 1a the example, controllers 1-4 and controller 21 are used as operation points for receiving the first service signal, simply referred to as source-operation. As Figure 1b shown, on the basis of Figure 1a , the second node 103 further includes controller 7 and controller 8. The first node 102 further includes controller 5 and controller 6. The first CPE 101 includes controller 22. Controllers 5-8 and controller 22 are used as operation points for receiving the second service signal, simply referred to as sink-operation. The process of the second CPE 104 sending the second service signal to the first CPE 101 will be described below.

[0073] As Figure 1b shown, a third SNCP protection group is established between the second CPE 104 and the second node 103. The working path of the third SNCP protection group is C1, and the protection path of the third SNCP protection group is C2. The second CPE 104 transmits the second service signal to the second node 103 via C1 and C2 respectively. The second node 103 is used to determine whether C1 has a fault. When C1 has no fault, the second node 103 receives the second service signal via C1. When C1 has a fault, the second node 103 receives the second service signal via C2. For example, the second node 103 is used to transmit the second service signal to controller 7 and controller 8 respectively. When C1 has no fault, controller 7 and controller 8 select to receive the second service signal from C1. When C1 has a fault, controller 7 and controller 8 switch the receiving path and select to receive the second service signal from C2. Controller 7 is connected to B1. Controller 8 is connected to B2. Controller 7 and controller 8 are used to output the second service signal respectively.

[0074] As Figure 1bAs shown in the figure, a second SNCP protection group is established between the second node 103 and the first node 102. The working path of the second SNCP protection group is the first service channel, and the protection path of the second SNCP protection group is the second service channel. The second node 103 is used to transmit the second service signal to the first node 102 through the first primary service channel (B1) and the first standby service channel (B2) respectively. The first primary service channel is carried on the first service channel. The first standby service channel is carried on the second service channel. The first node 102 is used to determine whether the first service channel has a fault. When the first node 102 determines that the first service channel has no fault, the first node 102 does not perform a switchover and receives the second service signal through the first service channel. When the first node 102 determines that the first service channel has a fault, the first node 102 switches the receiving path and receives the second service signal through the second service channel. For example, the first node 102 is used to transmit the second service signal to the controller 5 and the controller 6 respectively. The controller 5 and the controller 6 are used to select and receive the second service signal from B1 or B2. When the first service channel has no fault, the controller 5 receives the second service signal through B1, and the controller 5 receives the second service signal through B2. When the first service channel has a fault, the controller 5 switches the receiving path, and the controller 5 receives the second service signal through B2. The controller 6 receives the second service signal through B2. The controller 5 is connected to A1. The controller 6 is connected to A2. The controller 5 and the controller 6 are used to output the second service signal respectively.

[0075] As Figure 1b shown in the figure, a first SNCP protection group is established between the first CPE 101 and the first node 102. The working path of the first SNCP protection group is A1, and the protection path of the first SNCP protection group is A2. The first CPE 101 determines whether the transmission path before the first CPE 101 has a fault through the PM overhead. When the second CPE 104 determines through the PM overhead that the transmission path before the first CPE 101 has no fault, the first CPE 101 receives the second service signal through A1. When the second condition is met, the first CPE 101 switches the receiving path and receives the second service signal through A2. The second condition includes: the first CPE 101 determines through the PM overhead that the transmission path before the first CPE 101 has a fault (i.e., the first CPE 101 detects a PM fault). For example, the first CPE 101 includes a controller 22. When the first CPE 101 does not detect a PM fault, the controller 22 selects to receive the second service signal from A1. When the first CPE 101 detects a PM fault, the controller 22 switches the receiving path and selects to receive the second service signal from A2.

[0076] It should be understood that Figure 1b the description of transmitting the second service signal in Figure 1aThere are similarities in the description of transmitting the first service signal in [reference]. Therefore, regarding Figure 1b the description of transmitting the second service signal in [reference], reference can be made to the aforementioned Figure 1a description of transmitting the first service signal in [reference]. For example, in Figure 1b [reference], the second node 103 can determine whether the third transmission path is faulty through the TCM overhead. Another example is that the first CPE 101 determines whether the first transmission path is faulty through the TCM overhead. When the first CPE 101 determines that the first transmission path is faulty through the TCM overhead, the first CPE 101 performs a switchover. In the subsequent examples, taking the transmission direction of the first service signal as an example, the optical communication system of the present application is described. Regarding the description of the second service signal, reference can be made to the description of the first service signal.

[0077] In the present application, according to the transmission direction of the service signal, the nodes adjacent to the communication node can be referred to as the upper-level communication node and the lower-level communication node. For example, in Figure 1a the example of [reference], the first node 102 is the lower-level communication node of the first CPE 101. The first CPE 101 is the upper-level communication node of the first node 102, and the second node 103 is the lower-level communication node of the first node 102. The first node 102 is the upper-level communication node of the second node 103.

[0078] It should be understood that Figure 1b the central node in [reference] can be divided into two parts. The two parts are regarded as two independent devices. For example, the first node 102 includes a first device and a second device. The first device includes control points 5 and 1. The second device includes control points 6 and 2. The control point 5 of the first device is connected to the control point 2 of the second device. The control point 1 of the first device is connected to the control point 6 of the second device. In Figure 1a the example of [reference], when the first service channel is fault-free, the controller 3 is connected to B1 and C1, and the controller 4 is connected to B2 and C2. When the first service channel is faulty, the controller 3 is connected to B2 and C1, and the controller 4 is connected to B2 and C2. When the first service channel is fault-free, the second CPE 104 receives the first service signal through C1 and B1. When the first service channel is faulty, the second CPE 104 receives the first service signal through C1 and B2. When the first primary service channel is fault-free, the second CPE 104 receives the first service signal through C1 and B1. When the first primary service channel is faulty, the second CPE 104 receives the first service signal through C2 and B2. At this time, the first service signal is transmitted between the first node 102 and the second node 103 through two high-order channels. In practical applications, the first service signal can also be transmitted between the first node 102 and the second node 103 through four high-order channels, which will be described below. Figure 2This is the third structural schematic diagram of the optical communication system provided by the embodiments of this application. As Figure 2 shown, on the basis of Figure 1a , the first node 102 further includes a controller 11 and a controller 12. The first node 102 is used to transmit the first service signal to the controller 1, the controller 2, the controller 11, and the controller 12 respectively. A first service channel, a second service channel, a third service channel, and a fourth service conduction are established between the first node 102 and the second node 103. The controller 1 is connected to the first primary service channel (B1) in the first service channel. The controller 2 is connected to the first standby service channel (B2) in the second service channel. The controller 11 is connected to the third primary service channel (D1) in the third service channel. The controller 12 is connected to the third standby service channel (D2) in the fourth service channel. The third service channel and the fourth service channel are corresponding SNCP protection groups.

[0079] The first node 102 is used to transmit the first service signal to the second node 103 through B1, B2, D1, and D2 respectively. When the first service channel is fault-free, the controller 3 is connected to B1 and C1, and the controller 4 is connected to D1 and C2. When the first service channel fails, the controller 3 is connected to B2 and C1, and the controller 4 is connected to D1 and C2. When the first service channel is fault-free, the second CPE 104 receives the first service signal through C1 and B1. When the first service channel fails, the second CPE 104 receives the first service signal through C1 and B2. When the first primary service channel is fault-free, the second CPE 104 receives the first service signal through C1 and B1. When the first primary service channel fails, the second CPE 104 receives the first service signal through C2 and D1.

[0080] In Figure 1a 's example, the first primary service channel failure and the second service channel failure may occur simultaneously in the optical communication system. The second service channel failure will cause B2 to fail. At this time, the first service signal in the optical communication system will be interrupted. In Figure 2 's example, if the first primary service channel failure and the second service channel failure occur simultaneously in the optical communication system, the second CPE104 can receive the first service signal through C2 and D1. On this basis, if the optical communication system also includes a third service channel failure, the second node 103 can perform a re-switching so that the controller 4 receives the first service signal from D2. At this time, the controller 4 is connected to D2 and C2. The second CPE 104 receives the first service signal through C2 and D2.

[0081] In practical applications, if a first primary service channel fails in an optical communication system, the second CPE 104 receives the first service signal through C2 and D1. If a third service channel failure and a fourth service channel failure occur at this time, the second CPE 104 will be unable to receive the first service signal normally. However, there is still a second service channel between the first node 102 and the second node 103 through which the first service signal can be transmitted normally, resulting in a waste of resources. Therefore, in practical applications, the second node 103 can adjust the switching conditions. For example, Figure 2 In the example of, when a first primary service channel failure, D1 failure (or third service channel failure), and D2 failure (or fourth service channel failure) occur, the second node 103 performs a switch so that the controller 3 receives the first service signal from B2. At this time, the second CPE 104 receives the first service signal through C1 and B2.

[0082] According to Figure 1a the description of, a communication node can determine whether there is a failure through TCM overhead or PM overhead. In practical applications, a communication node can also determine whether there is a failure through an APS message. For example, in Figure 1b the example of transmitting a second service signal, after the first CPE 101 determines that there is a failure in the transmission link before the first CPE 101, the first CPE 101 generates a second APS message. The second APS message indicates that there is a PM failure in the transmission link before the first CPE 101 in the transmission direction of the second service signal, that is, it indicates that there is a PM failure in the transmission link before the second CPE 104 in the transmission direction of the first service signal. The first CPE 101 sends the second APS message to the second CPE 104. The second CPE 104 determines according to the second APS message that there is a PM failure in the transmission link before the second CPE 104 in the transmission direction of the first service signal. Another example is that in Figure 1b the example of transmitting a second service signal, after the second node 103 determines that there is a failure in the third transmission path, the second node 103 generates a first APS message. The first APS message indicates that there is a TCM failure in the third transmission path in the transmission direction of the second service signal, that is, it indicates that there is a TCM failure in the third transmission path in the transmission direction of the first service signal. The second node 103 sends the first APS message to the second CPE 104. The second CPE 104 determines according to the first APS message that there is a TCM failure in the third transmission path in the transmission direction of the first service signal.

[0083] It should be understood that Figure 1a 、 Figure 1b and Figure 2These are several examples of the optical communication system provided by the embodiments of the present application. In practical applications, those skilled in the art can adaptively modify the structure of the optical communication system according to requirements. Several possible exemplary modifications are described below.

[0084] In the first example, the first CPE 101 transmits the first service signal to the first node 102 through A1 and does not transmit the first service signal to the first node 102 through A2. At this time, A1 and A2 are not corresponding SNCP protection groups. The first node 102 does not need to perform a switchover according to the failure of A1. Similarly, in the transmission direction of the second service signal, the first node 102 transmits the second service signal to the first CPE 101 through A1. The first CPE 101 does not need to perform a switchover according to the failure of A1.

[0085] In the second example, there are also other communication nodes between the second node 103 and the second CPE 104. Figure 3 This is the fourth structural schematic diagram of the optical communication system provided by the embodiments of the present application. As Figure 3 shown, on the basis of Figure 1a , there is also a third node 301 between the second node 103 and the second CPE 104. There is a fourth SNCP protection group between the third node 301 and the second node 103. The working path of the fourth SNCP protection group is E1, and the protection path of the first SNCP protection group is E2. The object of the fourth SNCP protection group is the low-order channel. The second node 103 is used to transmit the first service signal to the third node 301 through the fourth primary service channel in the fifth service channel (E1) and the fourth standby service channel in the sixth service channel (E2) respectively. The fifth service channel and the sixth service channel are corresponding SNCP protection groups. It should be understood that the description of the transmission of service signals between the second node 103 and the third node 301 is similar to the description of the transmission of service signals between the first node 102 and the second node 103. Therefore, for the description of the transmission of service signals between the second node 103 and the third node 301, reference can be made to the description of the transmission of service signals between the first node 102 and the second node 103. Similarly, in practical applications, on the basis of the Figure 1a optical communication system, one or more communication nodes can be added between any two adjacent communication nodes. One or more communication nodes are used as the endpoints of the SNCP protection group. In the Figure 3 example, the first CPE 101 and the first node 102 are used as the endpoints of the first SNCP protection group. The first node 102 and the second node 103 are used as the endpoints of the second SNCP protection group. The second node 103 and the third node 301 are used as the endpoints of the fourth SNCP protection group. The third node 301 and the second CPE 104 are used as the endpoints of the third SNCP protection group.

[0086] In the third example, based on the Figure 1a optical communication system, one or more communication nodes can be added between any two adjacent communication nodes. One or more communication nodes do not act as endpoints of the SNCP protection group. Figure 4 This is the fifth schematic structural diagram of the optical communication system provided by the embodiments of the present application. As Figure 4 shown, based on Figure 1a , a fourth node 401 is further included between the first node 102 and the second node 103. The fourth node 401 transparently transmits the first service signal from the first node 102. Therefore, the fourth node 401 does not act as an endpoint of the SNCP protection group. In the example of Figure 4 , the first node 102 and the second node 103 act as endpoints of the second SNCP protection group.

[0087] In the fourth example, based on Figure 3 , communication nodes are added between the edge node and the central node. The added communication nodes act as endpoints of the SNCP protection group. The added communication nodes transparently transmit service signals to the edge node, that is, no SNCP protection group is set between the added communication nodes and the edge node. Figure 5 This is the sixth schematic structural diagram of the optical communication system provided by the embodiments of the present application. As Figure 5 shown, based on Figure 3 , the first node 102 is also called the first aggregation node. The second node 103 is also the core node. The third node 301 is also called the second aggregation node. A first CO 501 is included between the first CPE 101 and the first node 102. A second CO 502 is included between the third node 301 and the second CPE 104. No SNCP protection group is set between the first CPE 101 and the first CO 501. The first CPE 101 is used to transmit the first service signal to the first CO 501. A first SNCP protection group is set up between the first CO 501 and the first node 102. The first CO 501 transmits the first service signal to the first node 102 through A1 and A2 respectively. The first CO 501 and the first node 102 act as endpoints of the first SNCP protection group. A third SNCP protection group is set up between the third node 301 and the second CO502. The third node 301 transmits the first service signal to the second CO 502 through C1 and C2 respectively. The third node 301 and the second CO 502 act as endpoints of the third SNCP protection group. The second CO 502 is used to transmit the first service signal to the second CPE104. No SNCP protection group is set up between the second CO 502 and the second CPE 104.

[0088] In the fifth example, based on Figure 5 , an SNCP protection group is set between the edge node and the central node. Figure 6This is the seventh structural schematic diagram of the optical communication system provided by the embodiments of the present application. As Figure 6 shown, based on Figure 5 , the first CPE 101 and the first CO 501 are provided with an SNCP protection group. The first CPE 101 transmits the first service signal to the first CO 501 through two transmission paths in the SNCP protection group respectively. The first CO 501 selects to receive the first service signal from the working path or the protection path. The second CO 502 and the second CPE 104 are provided with an SNCP protection group. The second CO 502 transmits the first service signal to the second CPE 104 through two transmission paths in the SNCP protection group respectively. The second CPE 104 selects to receive the first service signal from the working path or the protection path. For the description of the SNCP protection group, reference can be made to the description of the first SNCP protection group or the fourth SNCP protection group above.

[0089] The optical communication system provided by the present application has been described above. Next, the SNCP switching method and related devices provided by the present application will be described. Figure 7 This is the first process schematic diagram of the SNCP switching method provided by the embodiments of the present application. As Figure 7 shown, the SNCP switching method includes the following steps.

[0090] In step 701, the second node receives the first service signal from the first node through the first main service channel in the first service channel. The first service channel and the second service channel are corresponding SNCP protection groups, and the second node does not perform switching according to the fault information of the first main service channel.

[0091] A second SNCP protection group is established between the first node and the second node. The working path of the second SNCP protection group is the first service channel, and the protection path of the second SNCP protection group is the second service channel. The object of the second SNCP protection group is the high-order channel. The first node is used to transmit the first service signal to the second node through the first main service channel (B1) in the first service channel and the first standby service channel (B2) in the second service channel respectively. The first service channel and the second service channel are corresponding SNCP protection groups. The second node does not perform switching according to the fault of the low-order channel, but performs switching according to the fault of the high-order channel. When the second node determines that the first service channel is fault-free, the second node does not perform switching and receives the first service signal through the first service channel. When the second node determines that the first service channel has a fault, the second node switches the receiving path and receives the first service signal through the second service channel.

[0092] In step 702, the second node transmits the first service signal to the second CPE through the second primary service channel and the second standby service channel respectively. The second CPE is used to switch the channel for receiving the first service signal according to the PM fault.

[0093] A third SNCP protection group is established between the second node and the second CPE. The working path of the third SNCP protection group is the second primary service channel C1, and the protection path of the third SNCP protection group is the second standby service channel C2. The object of the third SNCP protection group can be a low-order channel. The second node transmits the first service signal to the second CPE through the second primary service channel and the second standby service channel respectively. The second CPE is used to switch the channel for receiving the first service signal according to the PM fault.

[0094] It should be understood that Figure 7 the description of the SNCP switching method in Figure 1a and Figure 1b and Figures 2 - 6 has similarities with the description of the optical communication system in any of the foregoing Figure 7 Therefore, for the description of the SNCP switching method in Figure 1a and Figure 1b and Figures 2 - 6 reference can be made to the description of the optical communication system in any of the foregoing

[0095] Figure 8 This is the second process schematic diagram of the SNCP switching method provided by the embodiment of the present application. As Figure 8 shown, the SNCP switching method includes the following steps.

[0096] In step 801, the second CPE receives the first service signal from the second node through the second primary service channel. The second node is used to receive the first service signal from the first node through the first primary service channel in the first service channel. The first service channel and the second service channel are corresponding SNCP protection groups.

[0097] A second SNCP protection group is established between the first node and the second node. The working path of the second SNCP protection group is the first service channel, and the protection path of the second SNCP protection group is the second service channel. The object of the second SNCP protection group is the high-order channel. The first node is used to transmit the first service signal to the second node through the first primary service channel in the first service channel and the first standby service channel in the second service channel respectively. The first service signal is also referred to as the first service signal. The first service channel and the second service channel correspond to the SNCP protection group. A third SNCP protection group is established between the second node and the second CPE. The working path of the third SNCP protection group is C1, and the protection path of the third SNCP protection group is C2. The object of the third SNCP protection group can be the low-order channel.

[0098] In step 802, if the first condition is satisfied, the second CPE receives the first service signal through the second standby service channel, and the first condition includes that the second CPE detects a PM fault.

[0099] The second CPE can determine whether there is a fault in the transmission path before the second CPE 104 through the PM overhead. For example, when a B1 transmission fault occurs, the second node will write the fault information into the PM overhead. When the second CPE determines through the PM overhead that there is no fault in the transmission path before the second CPE, the second CPE receives the first service signal through C1. When the first condition is satisfied, the second CPE switches the receiving path and receives the first service signal through C2. The first condition includes: the second CPE 104 detects a PM fault. The second CPE 104 can determine whether there is a PM fault through the PM overhead in the first service signal or through the second APS message.

[0100] It should be understood that the description of the SNCP switching method in Figure 8 and the descriptions of the optical communication system in any of the foregoing Figure 1a , Figure 1b and Figures 2 - 6 have similarities. Therefore, for the description of the SNCP switching method in Figure 8 , reference can be made to the descriptions of the optical communication system in any of the foregoing Figure 1a , Figure 1b and Figures 2 - 6 For example, the first condition further includes: after detecting a PM fault and after a first defect confirmation time, the PM fault has not been eliminated. Another example is that if the second CPE detects a TCM fault, the second CPE switches the channel for receiving the first service signal.

[0101] Figure 9 This is the first structural schematic diagram of the second node provided by the embodiment of the present application. As shown in Figure 9As shown in the figure, the second node 900 includes a receiving unit 901 and a transmitting unit 902. The receiving unit 901 is configured to receive the service signal of the first customer premise equipment (CPE) from the first node through the first primary service channel in the first service channel. The first service channel and the second service channel form a corresponding SNCP protection group. The second node does not perform switching based on the fault information of the first primary service channel. The transmitting unit 902 is configured to transmit the first service signal to the second CPE through the second primary service channel and the second standby service channel respectively. The second CPE is configured to switch the channel for receiving the first service signal according to the PM fault.

[0102] It should be understood that Figure 9 the description of the communication node 900 in Figure 1a and Figure 1b and Figures 2 - 6 has similarities with the description of the optical communication system in any of the foregoing Figure 9 figures. Therefore, for the description of the communication node 900 in Figure 1a and Figure 1b and Figures 2 - 6 any figure, reference can be made to the description of the optical communication system in any of the foregoing

[0103] Figure 10 This is the first structural schematic diagram of the second CPE provided by the embodiment of the present application. As Figure 10 shown in the figure, the second CPE 1000 includes a receiving unit 1001 and a processing unit 1002. The receiving unit 1001 is configured to receive the first service signal from the second node through the second primary service channel. The second node is configured to receive the first service signal from the first node through the first primary service channel in the first service channel. The first service channel and the second service channel form a corresponding SNCP protection group. The processing unit 1002 is configured to determine whether a PM fault is detected. If the first condition is satisfied, the receiving unit 1001 is configured to perform switching and receive the first service signal through the second standby service channel. The first condition includes that the processing unit 1002 detects a PM fault.

[0104] It should be understood that Figure 10 the description of the second CPE 1000 in Figure 1a and Figure 1b and Figures 2 - 6 has similarities with the description of the optical communication system in any of the foregoing Figure 10 figures. Therefore, for the description of the second CPE 1000 in Figure 1a and Figure 1b and Figures 2 - 6Description of the optical communication system in any figure. For example, the first condition further includes: after detecting a PM fault and after a first defect confirmation time, the PM fault has not been eliminated. Another example is that if the processing unit 1002 detects a TCM fault, the processing unit 1002 switches the channel for receiving the first service signal.

[0105] Figure 11 This is the second structural schematic diagram of the second node provided by the embodiment of the present application. As Figure 11 shown, the second node 1100 includes a receiver 1101 and a transmitter 1102. The receiver 1101 is also referred to as an optical receiver or an optical receiving module. The transmitter 1102 is also referred to as an optical transmitter or an optical transmitting module. The receiver 1101 is used to receive the first service signal from the first node through the first primary service channel in the first service channel. The first service channel and the second service channel are corresponding SNCP protection groups. The second node 1100 does not perform a switchover based on the fault information of the first primary service channel. The transmitter 1102 transmits the first service signal to the second CPE through the second primary service channel and the second standby service channel respectively. The second CPE is used to switch the channel for receiving the first service signal according to the PM fault.

[0106] It should be understood that the description of the second node 1100 in Figure 11 has similarities with the description of the optical communication system in any of the foregoing Figure 1a , Figure 1b and Figures 2 - 6 figures. Therefore, for the description of the second node 1100 in Figure 11 , reference can be made to the description of the optical communication system in any of the foregoing Figure 1a , Figure 1b and Figures 2 - 6 figures. For example, the transmitter 1102 is also used to send a first APS message to the second CPE. The first APS message includes information about the TCM fault. The information about the TCM fault is used for the second CPE to switch the channel for receiving the first service signal according to the TCM fault.

[0107] In other embodiments, the second node 1100 may further include a processor. The processor may be a central processing unit (CPU), a network processor (NP), or a combination of a CPU and an NP. The processor 702 may further include a hardware chip or other general-purpose processor. The above-mentioned hardware chip may be an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The processor is used to determine whether a high-order channel failure occurs in the second transmission path between the second node and the first node.

[0108] Figure 12 This is the second structural schematic diagram of the second CPE provided by the embodiments of the present application. As Figure 12 shown, the second CPE 1200 includes a receiver 1201 and a processor 1202. The receiver 1201 is used to receive the first service signal from the second node through the second primary service channel. The second node is used to receive the first service signal from the first node through the first primary service channel in the first service channel. The first service channel and the second service channel are corresponding SNCP protection groups. For the description of the processor 1202, reference may be made to the description of the processor in the foregoing Figure 11 The processor 1202 is used to determine whether a PM failure is detected. If the first condition is satisfied, the receiver 1201 is used to perform a switchover and receive the first service signal through the second standby service channel. The first condition includes that the processor 1202 detects a PM failure.

[0109] It should be understood that the description of the second CPE 1200 in Figure 12 and the description of the optical communication system in the foregoing Figure 1a 、 Figure 1b and Figures 2 - 6 in any figure have similarities. Therefore, for the description of the second CPE 1200 in Figure 12 , reference may be made to the description of the optical communication system in the foregoing Figure 1a 、 Figure 1b and Figures 2 - 6 in any figure. For example, the first condition further includes: after detecting a PM failure and after a first defect confirmation time, the PM failure has not been eliminated. Another example is that if the processor 1202 detects a TCM failure, the processor 1202 is used to switch the channel for receiving the first service signal.

[0110] In other embodiments, the second node 1100 and / or the second CPE 1200 may further include a memory. The memory may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), or a flash memory, etc. The volatile memory may be a random access memory (RAM).

[0111] The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should be covered by the protection scope of the present application.

Claims

1. An optical communication system, characterized in that, It includes a first customer premise equipment (CPE), a first node, a second node, and a second CPE, where: The first CPE is used to transmit a first service signal to the first node; The first node is used to transmit the first service signal to the second node through a first primary service channel and a first standby service channel respectively. The first primary service channel is carried on a first service channel, and the first standby service channel is carried on a second service channel. The first service channel and the second service channel are a corresponding subnet connection protection (SNCP) protection group; The second node is used to receive the first service signal through the first service channel; The second CPE and the second node are connected through a second primary service channel and a second standby service channel; If a first condition is met, the second CPE is used to perform a switchover and receive the first service signal through the second standby service channel. The first condition includes that the second CPE detects a path monitoring (PM) fault in the channel; 2. The optical communication system according to claim 1, wherein The second standby service channel is connected to the first standby service channel; 3. The optical communication system according to claim 1, wherein: The first node is further used to transmit the first service signal to the second node through a third primary service channel in a third service channel and a third standby service channel in a fourth service channel respectively. The third service channel and the fourth service channel are a corresponding SNCP protection group, and the second standby service channel is connected to the third primary service channel; 4. The optical communication system according to any one of claims 1 to 3, characterized in that, The first condition further includes that after detecting the PM fault and after a first defect confirmation time, the PM fault has not been eliminated; 5. The optical communication system according to claim 4, characterized in that, The time duration for the second node to switch the channel for receiving the first service signal from the first service channel to the second service channel is a first switching duration, and the first defect confirmation time is greater than the first switching duration; 6. The optical communication system according to claim 5, characterized in that, a < T ≤ b - a, where T is the first defect confirmation time, a is the first switching duration, b ranges from 40 milliseconds to 60 milliseconds, and b ≥ 2a; 7. The optical communication system according to any one of claims 1 to 6, wherein: If the second CPE detects a tandem connection monitoring (TCM) fault, the second CPE is used to receive the first service signal through the second primary service channel; 8. The optical communication system according to claim 7, wherein There is no corresponding defect confirmation time for the TCM fault; 9. The optical communication system according to claim 8, wherein: The second CPE is further used to receive a first automatic protection switching (APS) message from the second node, and the first APS message includes information about the TCM fault; The second CPE is further used to receive a second APS message from the first CPE, and the second APS message includes information about the PM fault; 10. The optical communication system according to any one of claims 1 to 9, characterized in that, The second node is a core node, the first node is a first aggregation node, and the communication system further includes a first central office, a second central office, and a second aggregation node, where: The first CPE is configured to transmit the first service signal to the second CPE sequentially through the first central office, the first aggregation node, the core node, the second aggregation node, and the second central office.

11. A subnet connection protection SNCP switching method, characterized in that, Comprising: The second customer premise equipment (CPE) receives a first service signal from a second node through a second primary service channel. The second node is configured to receive the first service signal from a first node through a first primary service channel. The first primary service channel is carried on a first service channel. The first service channel and the second service channel form a corresponding SNCP protection group. If a first condition is satisfied, the second CPE performs a switchover and receives the first service signal through a second standby service channel. The first condition includes that the second CPE detects a PM fault.

12. The SNCP switching method according to claim 11, wherein The second standby service channel is connected to the first standby service channel.

13. The SNCP switching method according to claim 11, characterized in that, The first node is further configured to transmit the first service signal to the second node through a third primary service channel in a third service channel and a third standby service channel in a fourth service channel respectively. The second standby service channel is connected to the third primary service channel.

14. The SNCP switching method according to any one of claims 11 to 13, characterized in that, The first condition further includes that after detecting the PM fault and after a first defect confirmation time, the PM fault has not been eliminated.

15. The SNCP switching method according to any one of claims 11 to 14, characterized in that, The method further includes: If the second CPE detects a TCM fault, the second CPE receives the first service signal through the second primary service channel.

16. The SNCP switching method according to claim 15, wherein There is no corresponding defect confirmation time for the TCM fault.

17. The SNCP switching method according to claim 16, wherein The method further includes: The second CPE receives a first APS message from the second node. The first APS message includes information about the TCM fault. The second CPE receives a second APS message from the first CPE. The second APS message includes information about the PM fault.

18. A second customer premise equipment CPE, characterized in that, Comprising a receiving unit and a processing unit, wherein: The receiving unit is configured to receive a first service signal from a second node through a second primary service channel. The second node is configured to receive the first service signal from a first node through a first primary service channel. The first primary service channel is carried on a first service channel. The first service channel and the second service channel form a corresponding subnet connection protection (SNCP) protection group. The processing unit is configured to determine whether a PM fault is detected. If a first condition is satisfied, the receiving unit is configured to perform a switchover and receive the first service signal through a second standby service channel. The first condition includes that the processing unit detects a PM fault.

19. A second customer premise equipment CPE, characterized in that, Comprising a receiver and a processor, wherein: The receiver is configured to receive a first service signal from a second node through a second primary service channel. The second node is configured to receive the first service signal from a first node through a first primary service channel. The first primary service channel is carried on a first service channel. The first service channel and the second service channel form a corresponding subnet connection protection (SNCP) protection group. The processor is configured to determine whether a PM fault is detected. If the first condition is satisfied, the receiver is used to perform a switchover and receive the first service signal through a second standby service channel, and the first condition includes that the processor detects a PM fault.

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