Method, device and system for multiplexing OSU to OPU

Abstract

The invention discloses a method, device and system for multiplexing an OSU to an OPU, and relates to the field of optical communication. The method comprises the following steps: a source end maps an OSU service to an OPU payload block according to a preset algorithm and rule, and performs payload block counting and numbering on the OPU payload block in a period by taking a P value as the period in the mapping process; after a source end inserts a PBP in OPU overhead, payload block counting number synchronization information is also inserted, the information is a counting number of a payload block to which a certain specific byte of a specified OPU payload area belongs, and the information is used for a host end to synchronously update a local payload block counting number according to the information. And the host end calculates the distribution position of the OSU service in the payload block according to the same algorithm and rule as the source end, writes the distribution position into a multiplexing structure identification configuration table, and looks up the table through the updated payload block counting number to obtain an OSU service channel number. According to the invention, crosstalk between channels can be avoided, the OSU service channel number can be quickly obtained, and the actual application requirement is met.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technology, and in particular to a method, device and system for multiplexing an OSU (Optical Service Unit) to an OPU (Optical Payload Unit). Background Art

[0002] OSU is a technical improvement made to address the technical shortcomings of traditional OTN (Optical Transport Network). It changes the traditional OTN's time-slot-based frame structure and adopts a more flexible payload block division method. It can achieve efficient transmission of Ethernet services such as FE / GE / 10GE / 25GE / 50GE / 100GE (bandwidth range from 2Mb / s to 10Gb / s) and CBR services such as STM-1 / STM-4 / VC-n (including E1), and supports k-level connections. The simplified bandwidth lossless adjustment mechanism can well meet customers' needs for flexible and variable service bandwidth.

[0003] The CCSA (China Communications Standards Association) standard defines an OSU base rate of 2.6 Mbps. Different types of customer services are mapped to the OSU, and the OSU rate they carry is a multiple of the base rate. The OSU frame is 192 bytes long.

[0004] The standard also defines a transmission cycle as the time it takes an OPU to continuously transmit P payload blocks (192 bytes). Each payload block contains one OSU frame. During the transmission cycle, the rate of each payload block is slightly higher than 2.6 Mb / s, which can carry the OSU base rate. For example, an OSU service with a rate of C*2.6 Mb / s would occupy C payload blocks within a transmission cycle.

[0005] like Figure 1 As shown in FIG, the P values for different ODU types within a transmission cycle defined in the standard are listed. Figure 1 The P values in ODU0 and ODU1 are integer multiples of the OPU payload length, but the P values of other types of ODU are not integer multiples of the OPU payload length. This will cause the positions of the P payload blocks in the OPU to change (slide continuously) during each transmission cycle. Figure 2 As shown, the first payload block in the dotted area (one transmission cycle) is at the third payload block position in the first row of the OPU frame, while the first payload block in the next transmission cycle is at the 16th payload block position in the third row of the OPU frame.

[0006] Therefore, the standard defines the OSU frame overhead TPN (Tributary Port Number) to identify the corresponding service channel number, and then uses CRC-8 to verify the correctness of the first 6 bytes of overhead including TPN, such as Figure 3 As shown, Figure 3 This is the OSU frame structure defined in the standard. However, this solution has the following technical problems: 1) The OSU frame uses CRC-8 to check 6 bytes of data. There is a certain probability that errors will not be detected, and the TPN cannot be guaranteed to be correct. In this case, the TPN may correspond to other OSU service channels, causing crosstalk between channels.

[0007] 2) When an OSU frame CRC-8 error is detected, the TPN is unreliable and cannot be mapped to the corresponding OSU service channel, making it impossible to determine which channel has the error. At the same time, the OSU frame with the CRC-8 error will be discarded, which will also increase the alarm detection time for protection switching. Summary of the Invention

[0008] The purpose of the present invention is to provide a method, device and system for multiplexing OSU to OPU, which can not only avoid crosstalk between channels and effectively improve the anti-interference ability between channels, but also quickly obtain the OSU service channel number corresponding to each payload block by looking up the table, provide support for quickly locating the wrong channel number, reduce the channel alarm detection time, and meet the actual application needs.

[0009] To achieve the above objectives, in a first aspect, an embodiment of the present invention provides a method for multiplexing an OSU to an OPU, the method comprising: The source end maps the OSU service to the OPU payload block according to the preset algorithm and rules. During the mapping process, the OPU payload blocks within the period are counted and numbered with the P value as the period. After the source end inserts the PBP into the OPU overhead, it also inserts payload block count number synchronization information into the OPU overhead. The payload block count number synchronization information is the count number of the payload block to which a specific byte in the payload area of the specified OPU belongs. The payload block count number synchronization information is used by the sink end to synchronously update the local payload block count number according to the information, and the sink end calculates the distribution position of each OSU service in the P payload blocks within the transmission period according to the same algorithm and rules as the source end and writes it into the multiplexing structure identification configuration table. By using the updated payload block count number as the address of the multiplexing structure identification configuration table for table lookup, the OSU service channel number corresponding to the payload block is obtained.

[0010] In combination with the first aspect, in one embodiment, the method also includes: the source end transmits the multiplexing structure identifier of the P payload blocks within the transmission period to the destination end through a non-data frame; the multiplexing structure identifier is used by the destination end to directly write it into the multiplexing structure identifier configuration table, without the need to calculate the distribution position of each OSU service in the P payload blocks within the transmission period according to the same algorithm and rules as the source end.

[0011] In combination with the first aspect, in one embodiment, the method further includes: the source end inserts verification information in the OPU overhead, and the verification information is the result of CRC calculation of the payload block count number synchronization information, which is used by the host end to verify the validity of the payload block count number synchronization information based on the information.

[0012] In a second aspect, an embodiment of the present invention further provides a method for multiplexing an OSU to an OPU, the method comprising: After the sink extracts the PBP in the OPU overhead and determines the boundary of the payload block through three OPU frames, it counts and numbers the payload blocks of the OPU within the period with the P value as a period; and synchronously updates the local payload block count number by extracting the payload block count number synchronization information in the OPU overhead; wherein the payload block count number synchronization information is the count number of the payload block to which a specific byte of the specified OPU payload area belongs; The sink end calculates the distribution position of each OSU service in the P payload blocks within the transmission cycle according to the same algorithm and rules as the source end, and writes it into the multiplexing structure identification configuration table; uses the updated payload block count number as the address of the multiplexing structure identification configuration table to look up the table and obtain the OSU service channel number corresponding to the payload block.

[0013] In combination with the second aspect, in one embodiment, the method also includes: if the destination end receives a multiplexing structure identifier transmitted by the source end through a non-data frame, it directly writes it into the multiplexing structure identifier configuration table without calculating the distribution position of each OSU service in the P payload blocks within the transmission cycle according to the same algorithm and rules as the source end.

[0014] In conjunction with the second aspect, in one embodiment, if check information is further inserted into the OPU overhead, and the check information is a result of CRC calculation of the payload block count number synchronization information, the method further includes: The sink extracts the check information in the OPU overhead and verifies the validity of the payload block count number synchronization information; if the verification is valid and the payload block count number synchronization information is the same as the count number of the payload block to which a specific byte of the locally corresponding designated OPU payload area belongs, a synchronization status identifier is generated; if the verification is invalid or the payload block count number synchronization information is different from the count number of the payload block to which a specific byte of the locally corresponding designated OPU payload area belongs, an out-of-sync status identifier is generated.

[0015] In combination with the second aspect, in one embodiment, the method further includes: the sink end obtains the OSU service channel number corresponding to the payload block according to the TPN identification method; when generating a synchronization status identifier, the sink end selects the result obtained by using the payload block count number to perform a table lookup as the channel number of the OSU frame; when generating an out-of-sync status identifier, the sink end selects the result obtained by using the TPN identification method as the channel number of the OSU frame.

[0016] In a third aspect, an embodiment of the present invention further provides a source device for implementing the method in the embodiment of the first aspect, wherein the source device includes an OSU mapping module and an OPU overhead insertion module; The OSU mapping module is used to: map the OSU service to the OPU payload block according to the preset algorithm and rules; during the mapping process, the OPU payload block within the period is counted and numbered with the P value as a period; The OPU overhead insertion module is used to: insert PBP into the OPU overhead, and insert payload block count number synchronization information into the OPU overhead, wherein the payload block count number synchronization information is the count number of the payload block to which a specific byte of the specified OPU payload area belongs; wherein the payload block count number synchronization information is used by the sink end to synchronously update the local payload block count number according to the information, and the sink end calculates the distribution position of each OSU service in P payload blocks within the transmission cycle according to the same algorithm and rules as the source end and writes the calculated value into the multiplexing structure identification configuration table, and obtains the OSU service channel number corresponding to the payload block by using the updated payload block count number as the address of the multiplexing structure identification configuration table for lookup.

[0017] In a fourth aspect, an embodiment of the present invention further provides a sink device for implementing the method in the embodiment of the second aspect, the sink device comprising an OPU overhead extraction module and a multiplexing structure identification table lookup module; The OPU overhead extraction module is used to: extract the PBP in the OPU overhead and determine the boundary of the payload block through three OPU frames; count the payload blocks of the OPU within the period with the P value as a period; and synchronously update the local payload block count number by extracting the payload block count number synchronization information in the OPU overhead; wherein the payload block count number synchronization information is the count number of the payload block to which a specific byte of the specified OPU payload area belongs; The multiplexing structure identifier table lookup module is used to: calculate the distribution position of each OSU service in P payload blocks within the transmission cycle according to the same algorithm and rules as the source end, and write it into the multiplexing structure identifier configuration table; use the updated payload block count number as the address of the multiplexing structure identifier configuration table to look up the table and obtain the OSU service channel number corresponding to the payload block.

[0018] In a fifth aspect, an embodiment of the present invention further provides a system for multiplexing OSUs to OPUs, the system comprising a source device as in the embodiment of the third aspect and a sink device as in the embodiment of the fourth aspect.

[0019] The beneficial effects of the technical solutions provided in the embodiments of the present application include: In this embodiment, after the source completes the mapping of OSU services to OPU payload blocks, it also inserts payload block count synchronization information into the OPU overhead. This payload block count synchronization information is used by the sink to synchronously update the local payload block count based on this information, ensuring that the payload block counts at the source and sink are consistent. This ensures that the sink obtains a correct and valid OSU service channel number when using the payload block count number as the address of the multiplexing structure identifier configuration table for table lookup. The sink only needs to calculate the distribution position of each OSU service within the P payload blocks within the transmission cycle according to the same algorithm and rules as the source, and synchronously update the local payload block count number using the payload block count synchronization information in the OPU overhead. This ensures that the multiplexing structure of the P payload blocks within the transmission cycle obtained by the source and sink are consistent. The OSU service channel number corresponding to the payload block can then be quickly looked up using the payload block count number. By adopting the solution of the embodiment of the present application, the consistency of the multiplexing structure of the P payload blocks obtained by the source and the destination within the transmission cycle can be effectively guaranteed, and the corresponding errors of the OSU service channels can be prevented, thereby avoiding crosstalk between channels and effectively improving the anti-interference capability between channels; and, by adopting the solution of the embodiment of the present application, even when the OSU frame CRC-8 detects an error, there is no need to rely on TPN, and no active packet loss will be achieved. The wrong channel number can be quickly located by looking up the table through the payload block count number, thereby reducing the time for channel alarm detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the P value of different ODU types within a transmission cycle defined in the CCSA standard; Figure 2 It is a schematic diagram of the transmission cycle in OPU; Figure 3 It is the OSU frame structure defined in the CCSA standard; Figure 4 This is a flow chart of an embodiment of a method for multiplexing OSUs to OPUs according to the first aspect of the present application; Figure 5 This is a schematic diagram of the specific process of step A1 in the embodiment of the present application; Figure 6 Schematic diagram of inserting payload block count number synchronization information and check information into POS1 to POS4 of the OPU overhead; Figure 7 This is a flow chart of another embodiment of the method for multiplexing OSUs to OPUs according to the first aspect of the present application; Figure 8 Schematic diagram of using IDLE frame to transmit multiplexing structure identification; Figure 9 This is a flow chart of an embodiment of a method for multiplexing OSUs to OPUs according to the second aspect of the present application; Figure 10 This is a flow chart of another embodiment of the method for multiplexing OSUs to OPUs according to the second aspect of the present application; Figure 11 This is a flow chart of another embodiment of the method for multiplexing OSUs to OPUs according to the second aspect of the present application; Figure 12 This is a functional module diagram of an embodiment of a source device of the present application; Figure 13 This is a functional module diagram of another embodiment of the source device of the present application; Figure 14 This is a functional module diagram of an embodiment of a sink device of the present application; Figure 15 This is a functional module diagram of another embodiment of the sink device of the present application; Figure 16 This is a functional module diagram of another embodiment of the sink device of the present application; Figure 17 This is a schematic diagram of the architecture of an embodiment of a system for multiplexing OSUs to OPUs in the present application. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] However, it should be noted that the examples described below are merely specific examples and are not intended to limit the embodiments of the present invention to the following specific steps, values, conditions, data, sequences, etc. All other embodiments derived by persons of ordinary skill in the art based on the embodiments in this application without inventive effort shall fall within the scope of protection of this application.

[0023] In a first aspect, an embodiment of the present application provides a method for multiplexing an OSU to an OPU.

[0024] In one embodiment, referring to Figure 4 As shown, Figure 4 This is a flow chart of an embodiment of the method for multiplexing OSU to OPU in the first aspect of the present application. Figure 4 As shown, a method for multiplexing an OSU to an OPU includes: Step A1: The source end maps the OSU service to the payload block of the OPU according to the preset algorithm and rules. During the mapping process, the payload blocks of the OPU within the period are counted and numbered with the P value as the period.

[0025] It can be understood that in order to realize the multiplexing of OSU to OPU in this embodiment, the OSU service needs to be mapped into the payload block of OPU at the source end first, and in the mapping process, the payload block of OPU within the transmission period will be counted and numbered with the P value as a period, in preparation for the subsequent insertion of payload block count number synchronization information in the OPU overhead.

[0026] For example, see Figure 5 As shown, as an optional implementation, step A1 specifically includes: A101. The source configures the number P of payload blocks within a transmission cycle based on the ODU type, calculates the distribution position of each OSU service within the P payload blocks within the transmission cycle according to a preset algorithm and rules, and stores the calculated position in the multiplexing structure identifier configuration table. For example, after the source chip is powered on, software can configure the number P of payload blocks within the transmission cycle based on the ODU type, and can calculate the distribution position of each OSU service within the P payload blocks within the transmission cycle using a preset equalization algorithm, either through software or hardware.

[0027] A102. After the source end determines the boundary of the payload block through three OPU frames, it counts and numbers the payload blocks of the OPU within the period with the P value as the period, and uses the payload block count number to look up the multiplexing structure identification configuration table to obtain the OSU service channel number corresponding to the payload block; if the OSU service channel corresponding to the payload block has OSU service data, the data is loaded into the payload block; if the OSU service channel corresponding to the payload block has no OSU service data, the IDLE frame is loaded into the payload block for filling.

[0028] Step A2: After the source end inserts the PBP (Payload Block Pointer) into the OPU overhead, it also inserts payload block count number synchronization information into the OPU overhead. The payload block count number synchronization information is the count number of the payload block to which a specific byte of the specified OPU payload area belongs. The payload block count number synchronization information is used by the sink end to synchronously update the local payload block count number based on the information. The sink end calculates the distribution position of each OSU service in the P payload blocks within the transmission cycle according to the same algorithm and rules as the source end and writes the calculated value into the multiplexing structure identifier configuration table. The sink end uses the updated payload block count number as the address of the multiplexing structure identifier configuration table for lookup to obtain the OSU service channel number corresponding to the payload block.

[0029] It can be understood that, unlike the prior art, this embodiment will insert payload block count number synchronization information into the OPU overhead after completing the mapping of the OSU service to the payload block of the OPU. The payload block count number synchronization information is used by the host end to synchronously update the local payload block count number based on the information, so that the payload block count numbers of the source end and the host end are consistent, thereby ensuring that when the host end uses the payload block count number as the address of the multiplexing structure identification configuration table for table lookup, it can obtain the correct and valid OSU service channel number.

[0030] In practical applications, payload block count synchronization information can be inserted into the reserved bytes (such as POS1 to POS2) of the OPU overhead. Furthermore, the payload block count synchronization information is the count number of the payload block to which a specific byte of the specified OPU payload area belongs. The specified OPU payload area can be the payload area of the current OPU frame, the payload area of the next OPU frame, or the payload area of the next OPU frame. The specific byte can be any specified byte in the OPU payload area, such as specifying the first byte as a specific byte. See Figure 6 As shown in the figure, the payload block count number synchronization information inserted in the overhead POS1~POS2 of each OPU frame is the count number of the payload block to which the first byte of the payload area of each OPU frame belongs in the P payload blocks of the transmission period (corresponding to b15~b0 in the figure).

[0031] Furthermore, to ensure the validity (correctness) of the payload block count number synchronization information, as an optional implementation, the source end also inserts check information into the OPU overhead. This check information is the result of a CRC calculation on the payload block count number synchronization information, which is used by the sink end to verify the validity of the payload block count number synchronization information based on this information. In actual applications, check information can also be inserted into the reserved bytes (such as POS3-POS4) of the OPU overhead; and when performing CRC calculation, the corresponding CRC type, such as CRC-8, CRC-16, etc., can be selected according to specific needs. This embodiment does not make specific restrictions. See Figure 6 As shown in the figure, check information is inserted into the overhead POS3~POS4 of each OPU frame. The check information is the result of using CRC-16 calculation on the payload block count number synchronization information in POS1~POS2 (corresponding to c15~c0 in the figure).

[0032] Through the above steps A1~A2, the processing content of OSU multiplexing to OPU can be completed on the source side; on the sink side, it is only necessary to calculate the distribution position of each OSU service in the P payload blocks within the transmission cycle according to the same algorithm and rules as the source, and use the payload block count number synchronization information in the OPU overhead to synchronize the local payload block count number. In this way, the multiplexing structure of the P payload blocks obtained by the source and sink in the transmission cycle is consistent, and then the OSU service channel number corresponding to the payload block can be quickly looked up by the payload block count number. The scheme of the embodiment of the present application can effectively ensure the consistency of the multiplexing structure of the P payload blocks obtained by the source and sink in the transmission cycle, prevent the OSU service channel from corresponding to the error, thereby avoiding crosstalk between channels and effectively improving the anti-interference ability between channels; and, using the scheme of the embodiment of the present application, even when the OSU frame CRC-8 detects an error, there is no need to rely on TPN, and no active packet loss will occur. The wrong channel number can be quickly located by looking up the payload block count number, thereby reducing the time of channel alarm detection.

[0033] In another embodiment, referring to Figure 7 As shown, Figure 7 This is a flow chart of another embodiment of the method for multiplexing OSU to OPU in the first aspect of the present application. Figure 7 As shown, a method for multiplexing an OSU to an OPU further includes: Step A3: The source end transmits the multiplexing structure identifiers of the P payload blocks within the transmission period to the sink end through a non-data frame; the multiplexing structure identifier is used by the sink end to directly write it into the multiplexing structure identifier configuration table, without the need to calculate the distribution position of each OSU service in the P payload blocks within the transmission period according to the same algorithm and rules as the source end.

[0034] It is understandable that in order to simplify the relationship between the sink configuration and the source configuration, reduce application complexity, and improve flexibility, in this embodiment, the source also transmits the multiplexing structure identifiers of the P payload blocks within the transmission cycle to the sink via non-data frames. In this way, the sink can directly write the transmitted multiplexing structure identifiers into the multiplexing structure identifier configuration table, eliminating the need to calculate the distribution position of each OSU service in the P payload blocks within the transmission cycle according to the same algorithm and rules as the source. This simplifies the sink configuration and allows it to adapt to different algorithms and rules.

[0035] Exemplarily, as an optional implementation manner, the source end transmits the multiplexing structure identifiers of P payload blocks within the transmission period to the sink end through a non-data frame, specifically including: A301. Count and number all non-data frames used to transmit multiplexing structure identifiers, recorded as seq_id. The value range of seq_id is 0 to ceiling(P / N)-1, where N is the number of multiplexing structure identifiers that can be transmitted by each non-data frame. For example, assuming that the non-data frame is an IDLE frame, since each IDLE frame can carry the multiplexing structure identifiers of N=60 payload blocks (i.e., the OSU service channel numbers of 60 payload blocks), there are a total of P=3840 payload blocks of multiplexing structure identifiers that need to be loaded, so the counting range of seq_id is 0~63.

[0036] A302. Set the type indication of the non-data frame, denoted as sub_type, to indicate that the non-data frame is used to transmit the multiplexing structure identifier; for example, when sub_type=11 is defined, it indicates that the non-data frame is used to transmit the multiplexing structure identifier.

[0037] A303. Obtain the OSU service channel numbers corresponding to the N payload blocks. In actual operation, seq_id*N to seq_id*N+N-1 may be used as addresses to obtain the corresponding OSU service channel numbers from the multiplexing structure configuration table.

[0038] A304: Load seq_id and sub_type into a non-data frame, and load the OSU service channel numbers corresponding to the N payload blocks as multiplexing structure identifiers into the non-data frame and transmit it to the sink.

[0039] Furthermore, to ensure the validity (correctness) of the information transmitted in the non-data frame (including seq_id, sub_type, and the OSU service channel numbers corresponding to the N payload blocks), the source verifies this information and transmits the verification result to the sink via a non-data frame. Specifically, the source transmits the multiplexing structure identifiers of the P payload blocks within the transmission period to the sink via a non-data frame, and also performs the following operations: 1. Take sub_type and seq_id as one data, perform CRC calculation, and obtain the verification results of sub_type and seq_id; 2. The OSU service channel number corresponding to each payload block is treated as a separate data and CRC calculation is performed to obtain the verification result of the OSU service channel number corresponding to each payload block; 3. Load the verification results of sub_type and seq_id and the verification results of the OSU service channel number corresponding to each payload block into a non-data frame and transmit it to the sink.

[0040] It is understandable that when performing CRC calculation, the corresponding CRC type can be selected according to specific needs, such as CRC-8, CRC-12, CRC-16, etc., which is not specifically limited in this embodiment. Moreover, in actual applications, the non-data frames may include IDLE frames, customer fault frames, keep-alive frames, maintenance status frames, OAM frames, etc. For example, since the rate of the payload block defined in the standard has a positive frequency deviation of more than 1000ppm relative to the reference rate of the OSU, there will be many IDLE frames inserted as filler in the payload block of the OPU. Therefore, the IDLE frame can be used to transmit the multiplexing structure identifier. Moreover, when loading the non-data frame used to transmit the multiplexing structure identifier, it can be in accordance with a pre-specified format. For example, see Figure 8 As shown in the figure, when the IDLE frame is used to transmit the multiplexing structure identifier, the sub_type, seq_id and the corresponding CRC-12 check result can be loaded in the 8th, 9th and 10th bytes of the IDLE frame. In the subsequent bytes, the OSU service channel numbers of all payload blocks and their corresponding CRC-12 check results are loaded in sequence according to the order of one OSU service channel number and one channel number check result.

[0041] In a second aspect, an embodiment of the present application also provides a method for multiplexing an OSU to an OPU.

[0042] In one embodiment, referring to Figure 9 As shown, Figure 9 This is a flow chart of an embodiment of a method for multiplexing OSU to OPU according to the second aspect of the present application. Figure 9 As shown, a method for multiplexing an OSU to an OPU includes: Step B1: After the sink extracts the PBP in the OPU overhead and determines the boundary of the payload block through three OPU frames, it counts and numbers the payload blocks of the OPU within the period with the P value as a period; and by extracting the payload block count number synchronization information in the OPU overhead, the local payload block count number is synchronously updated to keep it consistent with the source end; wherein, the payload block count number synchronization information is the count number of the payload block to which a specific byte of the specified OPU payload area belongs.

[0043] It can be understood that, unlike the prior art, after receiving the OPU frame transmitted from the source, the sink will synchronize and update the local payload block count number by extracting the payload block count number synchronization information carried in the OPU overhead. Since the payload block count number synchronization information carried in the OPU overhead is the count number of the payload block to which a specific byte of the designated OPU payload area belongs, the sink can determine whether the payload block count numbers of the source and sink are synchronized by comparing whether the count number of the payload block to which a specific byte of the designated OPU payload area belongs in the local corresponding location is the same as the payload block count number synchronization information carried in the OPU overhead; and by synchronously updating the local payload block count number to keep it consistent with the source, it is ensured that when the payload block count number is subsequently used as the address of the multiplexing structure identification configuration table for table lookup, a correct and valid OSU service channel number can be obtained.

[0044] For example, assuming that the payload block count number synchronization information carried in the reserved fields POS1~POS2 of the OPU overhead is the count number of the payload block to which the first byte of the payload area of this OPU frame belongs, the sink end can compare the count number of the payload block to which the first byte of each local OPU payload area belongs with the count number in POS1~POS2 to determine whether the count numbers of the payload blocks of the source end and the sink end are synchronized; and the local payload block count number can be synchronously updated according to the count number in POS1~POS2 to keep it consistent with the source end.

[0045] Furthermore, as an optional implementation, if check information is inserted into the OPU overhead (such as POS3 to POS4), and the check information is the result of CRC calculation of the payload block count number synchronization information, then step B1 further includes: 1. The sink extracts the checksum information in the OPU overhead (such as POS3 and POS4) and verifies the validity of the payload block count synchronization information. During the verification, the result of the corresponding CRC calculation on the payload block count synchronization information is compared with the result in the checksum information. If the two are the same, the verification is valid; otherwise, the verification is invalid. 2. If the payload block count number synchronization information of M consecutive frames is verified to be valid and the payload block count number synchronization information is the same as the count number of the payload block to which a specific byte of the locally corresponding designated OPU payload area belongs, a synchronization status flag is generated; 3. If the verification of the payload block count number synchronization information of K consecutive frames is invalid or the payload block count number synchronization information is different from the count number of the payload block belonging to a specific byte of the locally corresponding designated OPU payload area, an out-of-sync status identifier is generated; where M and K are both integers greater than or equal to 1, and the specific values can be set and adjusted according to the situation, and this embodiment does not make specific limitations.

[0046] On this basis, as an optional implementation, in step B1, the local payload block count number is synchronously updated, including: When the synchronization state identifier is generated, the local payload block count number is synchronized and updated directly according to the payload block count number synchronization information; When the out-of-sync status flag is generated and the payload block count number synchronization information is verified to be valid, the local payload block count number needs to be synchronized and updated based on the payload block count number synchronization information and the accumulated calculation of the offset. For example, assuming that the ODU type is ODU2, and the payload block count number synchronization information carried in the reserved fields POS1~POS2 of the OPU2 overhead is the count number of the payload block to which the first byte of the payload area of this OPU2 frame belongs; then, when the out-of-sync status flag is generated, and the CRC-16 calculation result of POS1~POS2 is the same as the result in POS3~POS4, the value of POS1~POS2 is added to the offset value from the first payload block in the first row of the OPU2 payload area to the first payload block in the third row, and the accumulated result is used to update the local payload block count number, so that the payload block count numbers of the destination and source can be synchronized. There are three cases for payload block offset values, as shown below: When PBP=0, the payload block offset value is 39; When PBP=64, the payload block offset value is 40; When PBP=128, the payload block offset value is 40.

[0047] Step B2: The sink end calculates the distribution position of each OSU service in the P payload blocks within the transmission period according to the same algorithm and rules as the source end, and writes it into the multiplexing structure identification configuration table; uses the updated payload block count number as the address of the multiplexing structure identification configuration table to look up the table and obtain the OSU service channel number corresponding to the payload block.

[0048] It can be understood that in this embodiment, step B1 ensures that the payload block count numbers at the sink and source are consistent. In step B2, the sink calculates the distribution position of each OSU service within the P payload blocks within the transmission cycle according to the same algorithm and rules as the source, thereby ensuring that the multiplexing structures of the P payload blocks obtained by the sink and source within the transmission cycle are consistent. Subsequently, the updated payload block count number is used as the address of the multiplexing structure identifier configuration table for table lookup to obtain the OSU service channel number corresponding to the payload block. This entire implementation process not only prevents incorrect OSU service channel correspondence, thereby avoiding crosstalk between channels, but also effectively improves anti-interference capabilities between channels. Furthermore, using the solution of the embodiment of the present application, even when an OSU frame CRC-8 error is detected, there is no need to rely on TPN and no active packet loss. The incorrect channel number can be quickly located by table lookup using the payload block count number, thereby reducing the time for channel alarm detection.

[0049] In addition, it can also be understood that the CCSA standard defines that the generation or disappearance of the OSU frame loss alarm (LOF) is judged by the failure to receive or receipt of a valid OSU frame within 3ms. Its detection logic is complex and inaccurate, and the detection time is long. After adopting the solution of the embodiment of the present application, the sink end can use the transmission cycle (approximately 590us) to detect whether a valid OSU frame is received as a judgment, which can speed up the detection time of the OSU LOF and simplify its generation logic, thereby facilitating faster generation of maintenance status frames and reducing the time of OSU interruption.

[0050] Further, see Figure 10 As shown, Figure 10 This is a flow chart of another embodiment of the method for multiplexing OSU to OPU in the second aspect of the present application. Figure 10 As shown, in another embodiment, in step B2, if the sink receives the multiplexing structure identifier transmitted by the source via a non-data frame, it directly writes the identifier into the multiplexing structure identifier configuration table, eliminating the need to calculate the distribution position of each OSU service within the P payload blocks within the transmission cycle according to the same algorithm and rules as the source. In this embodiment, the sink can more quickly and directly obtain the distribution of the OSU services within the OPU payload blocks based on the multiplexing structure identifier sent by the source, eliminating the need to calculate the distribution position of each OSU service within the P payload blocks within the transmission cycle according to the same algorithm and rules as the source. This simplifies the sink configuration and allows it to adapt to different algorithms and rules.

[0051] For example, as an optional implementation, the sink receives the multiplexing structure identifier transmitted by the source through a non-data frame and directly writes it into the multiplexing structure identifier configuration table, including the following operations: 1. Identify the non-data frame used to transmit the multiplexing structure identifier based on the sub_type field; 2. Extract seq_id and the verification result of sub_type and seq_id from the non-data frame; perform CRC calculation on sub_type and seq_id, and compare them with the verification result of the extracted sub_type and seq_id; if the comparison is correct, give a valid non-data frame indication; otherwise, give an invalid non-data frame indication; 3. In the case of a non-valid data frame, extract the OSU service channel numbers corresponding to the N payload blocks and the check results of the corresponding OSU service channel numbers, perform CRC calculation on the OSU service channel number corresponding to each payload block, and compare them with the extracted check results of the corresponding OSU service channel numbers; if the comparison is correct, output the OSU service channel number and its valid channel identifier; otherwise, output the invalid channel identifier; 4. If the channel identifier is valid, the OSU service channel numbers corresponding to the N payload blocks output are used to update the contents of the corresponding addresses in the multiplexing structure identifier configuration table (i.e., addresses seq_id*N to seq_id*N+N-1). For example, if the extracted seq_id is 1 and the OSU service channel numbers corresponding to 60 payload blocks can be extracted from each non-data frame, then if the channel identifier is valid, the 60 output OSU service channel numbers will be used to update the corresponding OSU service channel numbers at addresses 60 to 119 in the multiplexing structure configuration table.

[0052] Furthermore, since out-of-sync states may occur in actual applications, in order to avoid using the updated payload block count number as the address of the multiplexing structure identification configuration table for lookup in the out-of-sync state, which may cause the OSU service channel number corresponding to the obtained payload block to be inaccurate or wrong, it is possible to consider combining the existing method of identifying the corresponding service channel number through the overhead TPN of the OSU frame to further ensure that the accurate OSU service channel number can still be obtained in the out-of-sync state.

[0053] Specifically, in another embodiment, referring to Figure 11 As shown, Figure 11 This is a flow chart of another embodiment of the method for multiplexing OSU to OPU in the second aspect of the present application. Figure 11 As shown, a method for multiplexing an OSU to an OPU further includes: Step B3: The sink obtains the OSU service channel number corresponding to the payload block according to the existing TPN identification method; Step B4: When generating a synchronization status flag, the sink end selects the result obtained by using the payload block count number to perform a table lookup as the channel number of the OSU frame; when generating an out-of-sync status flag, the sink end selects the result obtained by using the TPN identification method as the channel number of the OSU frame.

[0054] It is understandable that, in actual application, the sink end may obtain the OSU service channel number corresponding to the payload block according to the existing TPN identification method, which may include: 1. The sink extracts the corresponding TPN from the payload block. Specifically, the sink can calculate the CRC-8 on the first 6 bytes of the payload block and compare the calculation result with the 7th byte. If the comparison is the same and the overhead TPN is not all 1s, the TPN is extracted.

[0055] 2. The sink uses the extracted TPN as the address to look up the OSU service channel number corresponding to the payload block in a pre-configured TPN configuration table (i.e., the OSU service channel number corresponding to the TPN can be configured in the TPN configuration table in advance through software)

[0056] In a third aspect, an embodiment of the present application further provides a source-end device for implementing the method in the embodiment of the first aspect.

[0057] In one embodiment, referring to Figure 12 As shown, Figure 12 This is a functional module diagram of an embodiment of the source device of this application. Figure 12 As shown, a source end device includes: an OSU mapping module and an OPU overhead insertion module.

[0058] The OSU mapping module is used to: map the OSU service into the payload block of the OPU according to the preset algorithm and rules; during the mapping process, count and number the payload blocks of the OPU within the period with the P value as the period.

[0059] Specifically, the OSU mapping module maps the OSU service to the OPU payload block according to the preset algorithm and rules, including the following operations: 1. The OSU mapping module configures the number of payload blocks P within a transmission cycle based on the ODU type. It calculates the distribution position of each OSU service within the P payload blocks within the transmission cycle according to the preset algorithm and rules, and writes it into the multiplexing structure identification configuration table. For example, assuming the ODU type is ODU2, the number of payload blocks P within the transmission cycle can be configured as 3840. The software or hardware uses a uniformization algorithm to calculate the distribution position of each OSU service within the 3840 payload blocks within the transmission cycle and writes it into the multiplexing structure identification configuration table.

[0060] 2. After the OSU mapping module determines the boundary of the payload block through three OPU frames, it counts and numbers the payload blocks of the OPU within the period with the P value as the period. For example, assuming the ODU type is ODU2, the frame structure of ODU2 is generated, such as Figure 6As shown in the figure, the payload of every three OPU2 frames can be divided into 238 payload blocks; the first byte of the payload area of the first OPU2 frame is exactly the first byte of the 192-byte payload block, and the last byte of the payload area of the third OPU2 frame is exactly the last byte of the payload block; and the 3840 payload blocks in the transmission cycle are counted and numbered in the range of 0 to 3839.

[0061] 3. Use the payload block count number to look up the multiplexing structure identification configuration table to obtain the OSU service channel number corresponding to the payload block; if OSU service data has arrived in the OSU service channel corresponding to the payload block, load the data into the payload block; if no OSU service data has arrived in the OSU service channel corresponding to the payload block, load the IDLE frame into the payload block for filling.

[0062] The OPU overhead insertion module is used to: insert PBP into the OPU overhead, and insert payload block count number synchronization information into the OPU overhead, wherein the payload block count number synchronization information is the count number of the payload block to which a specific byte of the specified OPU payload area belongs; wherein the payload block count number synchronization information is used by the sink end to synchronously update the local payload block count number according to the information, and the sink end calculates the distribution position of each OSU service in P payload blocks within the transmission cycle according to the same algorithm and rules as the source end and writes the calculated value into the multiplexing structure identification configuration table, and obtains the OSU service channel number corresponding to the payload block by using the updated payload block count number as the address of the multiplexing structure identification configuration table for lookup.

[0063] In actual application, payload block count number synchronization information can be inserted into the reserved bytes (such as POS1~POS2) of the OPU overhead. In addition, in order to ensure the validity (correctness) of the payload block count number synchronization information, check information can also be inserted into the reserved bytes (such as POS3~POS4) of the OPU overhead. For example, assuming that the ODU type is ODU2, the OPU overhead insertion module will be as follows Figure 6 As shown in the figure, according to the positioning of the payload block boundary, the PBP of the first OPU2 frame is inserted into 0, the PBP of the second OPU2 frame is inserted into 64, and the PBP of the third OPU2 frame is inserted into 128; afterwards, the count number of the payload block corresponding to the first byte of the payload area of the OPU2 frame is recorded as the payload block count number synchronization information, inserted into the reserved bytes POS1 and POS2 of the OPU2 overhead, and a CRC-16 calculation is performed on it, and then the calculation result is inserted into the reserved bytes POS3 and POS4 of the OPU2 overhead.

[0064] Further, refer to Figure 13 As shown, Figure 13This is a functional module diagram of another embodiment of the source device of this application. Figure 13 As shown, in another embodiment, a source device further includes a multiplexing structure identifier insertion module. The multiplexing structure identifier insertion module is configured to transmit the multiplexing structure identifiers of the P payload blocks within a transmission period to the sink via a non-data frame; the sink is configured to directly write the multiplexing structure identifiers into a multiplexing structure identifier configuration table without having to calculate the distribution position of each OSU service within the P payload blocks within the transmission period according to the same algorithm and rules as the source.

[0065] For example, assuming that the ODU type is ODU2, and the multiplexing structure identifier insertion module uses an IDLE frame as a non-data frame for transmitting the multiplexing structure identifier, the multiplexing structure identifier insertion module transmits the multiplexing structure identifiers of P payload blocks in the transmission period to the sink end, which may include the following operations: First, count and number the IDLE frames. Since each IDLE frame can carry the multiplexing structure identifiers of 60 payload blocks, and there are a total of P=3840 payload block multiplexing structure identifiers that need to be loaded, the counting range of seq_id is 0~63; then, use seq_id*60 to seq_id*60+59 as addresses to obtain the corresponding OSU service channel number from the multiplexing structure configuration table; then, use sub_type and seq_id as 1 data to perform CRC-12 calculation; use the OSU service channel number corresponding to each payload block as 1 data separately to perform CRC-12 calculation; finally, according to Figure 8 The format of sub_type and seq_id and the CRC-12 calculation results of the two are loaded into the IDLE frame; the 60 OSU service channel numbers and their corresponding CRC-12 calculation results are loaded into the IDLE frame.

[0066] It should also be noted that the various variations and other specific examples in the aforementioned method embodiment of multiplexing OSU to OPU are also applicable to the source device of this embodiment. Through the detailed description of the aforementioned method, those skilled in the art can clearly understand the implementation method of the source device in this embodiment, so for the sake of brevity of the specification, it will not be described in detail here.

[0067] In a fourth aspect, an embodiment of the present application further provides a sink device for implementing the method in the embodiment of the second aspect.

[0068] In one embodiment, referring to Figure 14 As shown, Figure 14 This is a functional module diagram of an embodiment of the sink device of the present application. Figure 14 As shown, a sink device includes: an OPU overhead extraction module and a multiplexing structure identification table lookup module.

[0069] The OPU overhead extraction module is used to: extract the PBP in the OPU overhead and determine the boundary of the payload block through three OPU frames; count and number the payload blocks of the OPU within the period with the P value as a period; and synchronously update the local payload block count number by extracting the payload block count number synchronization information in the OPU overhead to keep it consistent with the source end; wherein the payload block count number synchronization information is the count number of the payload block to which a specific byte of the specified OPU payload area belongs.

[0070] For example, assuming the ODU type is ODU2, the OPU overhead extraction module extracts the OPU2 overhead PBP. If PBP is 0, the first byte of the OPU2 frame's payload area is the first byte of the payload block. If PBP is 64, the first byte of the OPU2 frame's payload area is the 65th byte of the payload block. If PBP is 128, the first byte of the OPU2 frame's payload area is the 129th byte of the payload block. Three OPU2 frames can thus determine the payload block boundaries. Based on these determined payload block boundaries, the input OPU2 payload is then numbered from 0 to 3839, with each payload block containing 192 bytes and a period of 3840. The payload block count synchronization information (POS1 and POS2) in the OPU2 overhead is then extracted from the received data stream according to the ODU2 frame structure, and the local payload block count is updated accordingly.

[0071] Furthermore, in actual applications, if check information is inserted into the OPU overhead (such as in POS3 and POS4), and the check information is the result of CRC calculation of the payload block count number synchronization information, then the OPU overhead extraction module is further used to: Extract the checksum information in the OPU overhead (such as POS3 and POS4) to verify the validity of the payload block count number synchronization information; If the payload block count number synchronization information of M consecutive frames is verified to be valid and the payload block count number synchronization information is the same as the count number of the payload block to which a specific byte of the locally corresponding designated OPU payload area belongs, a synchronization status flag is generated; If the verification of the payload block count number synchronization information of consecutive K frames is invalid or the payload block count number synchronization information is different from the count number of the payload block to which a specific byte of the locally corresponding designated OPU payload area belongs, an out-of-sync status flag is generated; When the synchronization state identifier is generated, the local payload block count number is synchronized and updated directly according to the payload block count number synchronization information; When the out-of-sync status flag is generated and the payload block count number synchronization information is verified to be valid, the local payload block count number needs to be synchronously updated based on the payload block count number synchronization information and the accumulated offset.

[0072] The multiplexing structure identifier table lookup module is used to: calculate the distribution position of each OSU service in P payload blocks within the transmission cycle according to the same algorithm and rules as the source end, and write it into the multiplexing structure identifier configuration table; use the updated payload block count number as the address of the multiplexing structure identifier configuration table to look up the table and obtain the OSU service channel number corresponding to the payload block.

[0073] Further, refer to Figure 15 As shown, Figure 15 This is a functional module diagram of another embodiment of the sink device of this application. Figure 15 As shown, in another embodiment, a sink device further includes: a multiplexing structure identifier extraction module. The multiplexing structure identifier extraction module is configured to: if the sink receives a multiplexing structure identifier transmitted by the source via a non-data frame, extract the multiplexing structure identifier from the non-data frame and directly write it into the multiplexing structure identifier configuration table. The multiplexing structure identifier table lookup module does not need to calculate the distribution position of each OSU service in the P payload blocks within the transmission cycle according to the same algorithm and rules as the source. In this embodiment, the multiplexing structure identifier extraction module can more quickly and directly obtain the distribution of the OSU service in the OPU payload block by extracting the multiplexing structure identifier sent by the source. This allows the subsequent multiplexing structure identifier table lookup module to directly perform the table lookup operation without having to calculate the distribution position of each OSU service in the P payload blocks within the transmission cycle according to the same algorithm and rules as the source.

[0074] Further, refer to Figure 16 As shown, Figure 16 This is a functional module diagram of another embodiment of the sink device of this application. Figure 16 As shown, in yet another embodiment, a sink device further includes: a TPN module and a selection module.

[0075] Among them, the TPN module is used to: obtain the OSU service channel number corresponding to the payload block according to the existing TPN identification method; the selection module is used to: when generating a synchronization status identifier, select and use the result output by the multiplexing structure identifier lookup module as the channel number of the OSU frame; when generating an out-of-sync status identifier, the host end selects and uses the result output by the TPN module as the channel number of the OSU frame.

[0076] For practical application, see Figure 16As shown, the TPN module may include a TPN extraction module and a TPN lookup module. The TPN extraction module is configured to extract the corresponding TPN from the payload block. Specifically, the TPN extraction module may perform a CRC-8 calculation on the first six bytes of the payload block and compare the result with the seventh byte. If the result is the same and the overhead TPN is not all 1s, the TPN is extracted. The TPN lookup module is configured to use the extracted TPN as an address to perform a lookup in a preconfigured TPN configuration table (i.e., the OSU service channel number corresponding to the TPN can be preconfigured in the TPN configuration table via software) to obtain the OSU service channel number corresponding to the payload block.

[0077] It should also be noted that the various variations and other specific examples in the aforementioned method embodiment of multiplexing OSU to OPU are also applicable to the host device of this embodiment. Through the detailed description of the aforementioned method, those skilled in the art can clearly understand the implementation method of the host device in this embodiment, so for the sake of brevity of the specification, it will not be described in detail here.

[0078] In a fifth aspect, an embodiment of the present invention further provides a system for multiplexing OSUs to OPUs.

[0079] In one embodiment, referring to Figure 17 As shown, Figure 17 This is a schematic diagram of the architecture of a system embodiment of the present application where OSU is multiplexed to OPU. Figure 17 As shown, a system for multiplexing OSU to OPU includes a source device as described in the third embodiment and a sink device as described in the fourth embodiment.

[0080] Note: The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit "first", "second" and "third" to different types.

[0081] In the description of the embodiments of this application, the words "exemplary," "for example," or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary," "for example," or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "for example," or "for example" is intended to present the relevant concepts in a concrete manner.

[0082] In some processes described in the embodiments of the present application, multiple operations or steps are included that appear in a specific order. However, it should be understood that these operations or steps may not be performed in the order in which they appear in the embodiments of the present application or may be performed in parallel. The sequence numbers of the operations are only used to distinguish between different operations, and the sequence numbers themselves do not represent any order of execution. In addition, these processes may include more or fewer operations, and these operations or steps may be performed in sequence or in parallel, and these operations or steps may be combined.

[0083] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, or the part that contributes to the existing technology, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above and includes a number of instructions for enabling a terminal device to execute the methods described in each embodiment of this application.

[0084] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for multiplexing OSU to OPU, characterized in that: The method includes: The source end maps the OSU service to the OPU payload block according to the preset algorithm and rules. During the mapping process, the OPU payload blocks within the period are counted and numbered with the P value as the period. After the source end inserts the PBP into the OPU overhead, it also inserts payload block count number synchronization information into the OPU overhead. The payload block count number synchronization information is the count number of the payload block to which a specific byte in the payload area of the specified OPU belongs. The payload block count number synchronization information is used by the sink end to synchronously update the local payload block count number according to the information, and the sink end calculates the distribution position of each OSU service in the P payload blocks within the transmission period according to the same algorithm and rules as the source end and writes it into the multiplexing structure identification configuration table. By using the updated payload block count number as the address of the multiplexing structure identification configuration table for table lookup, the OSU service channel number corresponding to the payload block is obtained.

2. The method for multiplexing OSU to OPU according to claim 1, wherein: The method further includes: The source end transmits the multiplexing structure identifiers of the P payload blocks within the transmission period to the sink end through non-data frames; the multiplexing structure identifier is used by the sink end to directly write it into the multiplexing structure identifier configuration table, without the need to calculate the distribution position of each OSU service in the P payload blocks within the transmission period according to the same algorithm and rules as the source end.

3. The method for multiplexing OSU to OPU according to claim 1, wherein: The method further includes: The source end inserts verification information into the OPU overhead. The verification information is the result of CRC calculation on the payload block count number synchronization information. The sink end verifies the validity of the payload block count number synchronization information based on the information.

4. A method for multiplexing OSU to OPU, characterized in that: The method includes: After the sink extracts the PBP in the OPU overhead and determines the boundary of the payload block through three OPU frames, it counts and numbers the payload blocks of the OPU within the period with the P value as a period; and synchronously updates the local payload block count number by extracting the payload block count number synchronization information in the OPU overhead; wherein the payload block count number synchronization information is the count number of the payload block to which a specific byte of the specified OPU payload area belongs; The sink end calculates the distribution position of each OSU service in the P payload blocks within the transmission cycle according to the same algorithm and rules as the source end, and writes it into the multiplexing structure identification configuration table; uses the updated payload block count number as the address of the multiplexing structure identification configuration table to look up the table and obtain the OSU service channel number corresponding to the payload block.

5. The method for multiplexing OSU to OPU according to claim 4, wherein: The method further includes: If the sink receives the multiplexing structure identifier transmitted by the source through a non-data frame, it directly writes it into the multiplexing structure identifier configuration table without having to calculate the distribution position of each OSU service in the P payload blocks within the transmission cycle according to the same algorithm and rules as the source.

6. The method for multiplexing OSU to OPU according to claim 4, wherein: If check information is further inserted into the OPU overhead, and the check information is a result of performing a CRC calculation on the payload block count number synchronization information, the method further includes: The sink extracts the checksum information in the OPU overhead and verifies the validity of the payload block count number synchronization information. If the verification is valid and the payload block count number synchronization information is the same as the count number of the payload block to which a specific byte of the designated OPU payload area corresponds locally, a synchronization status flag is generated; If the verification is invalid or the payload block count number synchronization information is different from the count number of the payload block to which a specific byte of the designated OPU payload area corresponds locally, an out-of-sync status flag is generated.

7. The method for multiplexing OSU to OPU according to claim 6, wherein: The method further includes: The sink obtains the OSU service channel number corresponding to the payload block according to the TPN identification method; When generating the synchronization status identifier, the sink selects the result obtained by using the payload block count number to perform a table lookup as the channel number of the OSU frame; When generating the out-of-sync status identifier, the sink selects the result obtained by using the TPN identification method as the channel number of the OSU frame.

8. A source device for implementing the method according to any one of claims 1 to 3, characterized in that: The source device includes an OSU mapping module and an OPU overhead insertion module; The OSU mapping module is used to: map the OSU service to the OPU payload block according to the preset algorithm and rules; during the mapping process, the OPU payload block within the period is counted and numbered with the P value as a period; The OPU overhead insertion module is used to: insert PBP into the OPU overhead, and insert payload block count number synchronization information into the OPU overhead, wherein the payload block count number synchronization information is the count number of the payload block to which a specific byte of the specified OPU payload area belongs; wherein the payload block count number synchronization information is used by the sink end to synchronously update the local payload block count number according to the information, and the sink end calculates the distribution position of each OSU service in P payload blocks within the transmission cycle according to the same algorithm and rules as the source end and writes the calculated value into the multiplexing structure identification configuration table, and obtains the OSU service channel number corresponding to the payload block by using the updated payload block count number as the address of the multiplexing structure identification configuration table for lookup.

9. A sink device for implementing the method according to any one of claims 4 to 7, characterized in that: The sink device includes an OPU overhead extraction module and a multiplexing structure identification table lookup module; The OPU overhead extraction module is used to: extract the PBP in the OPU overhead and determine the boundary of the payload block through three OPU frames; count the payload blocks of the OPU within the period with the P value as a period; and synchronously update the local payload block count number by extracting the payload block count number synchronization information in the OPU overhead; wherein the payload block count number synchronization information is the count number of the payload block to which a specific byte of the specified OPU payload area belongs; The multiplexing structure identifier table lookup module is used to: calculate the distribution position of each OSU service in P payload blocks within the transmission cycle according to the same algorithm and rules as the source end, and write it into the multiplexing structure identifier configuration table; use the updated payload block count number as the address of the multiplexing structure identifier configuration table to look up the table and obtain the OSU service channel number corresponding to the payload block.

10. A system for multiplexing OSUs to OPUs, characterized by: The system includes the source device according to claim 8 and the sink device according to claim 9.

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