Method and system for service clock transparent transmission in optical transport network

A system for service clock transparent transmission in an optical transport network (OTN), comprising a service accessing end and an OTN receiving end;

• wherein,
• the service accessing end is configured to:
• read a service data flow according to a service clock, and then encapsulate the service data flow into a payload of an OTN frame according to an OTN clock, and send the OTN frame to the OTN receiving end through the OTN;
• the OTN receiving end comprises a service de-mapping module and a service clock recovery module;
• the service de-mapping module is configured to perform a de-mapping operation to the OTN frame after receiving the OTN frame and recover the service data flow therefrom;
• the service clock recovery module is configured to perform a two-level buffering operation to the service data flow recovered by the service de-mapping module, wherein,
• the service clock recovery module comprises a first buffering unit and a second buffering unit;
• the first buffering unit is configured to perform a homogenization treatment to the service data flow and then output to the second buffering unit;
• the second buffering unit is configured to output the service data flow according to the service clock after receiving the service data flow after the homogenization treatment;
• wherein,
• the service clock recovery module further comprises a data reading control unit;
• the data reading control unit is configured to generate a reading enabling signal, and control a reading operation of the first buffering unit by using the reading enabling signal;
• wherein, a preset value of a ratio of a number of clock cycles indicating that a reading signal is in an enabling status of the reading enabling signal to a total number of clock cycles of the reading enabling signal equals to a quotient of service clock frequency and OTN clock frequency;
• the data reading control unit is further configured to continually adjust the number of clock cycles indicating that the reading signal is in the enabling status of the reading enabling signal accordingly through judging whether status of the first buffering unit is empty or full;
• the first buffering unit is configured to read the service data flow into the present unit according to an OTN clock, reads out the service data flow from the present unit according to the OTN clock under control of the reading enabling signal and sends to the second buffering unit.

An optical transport network (OTN) receiving apparatus of a system for service clock transparent transmission in an OTN, wherein, the OTN receiving apparatus comprises a service de-mapping module and a service clock recovery module;

• the service de-mapping module is configured to perform a de-mapping operation to an OTN frame after receiving the OTN frame and recover a service data flow therefrom;
• the service clock recovery module is configured to perform a two-level buffering operation to the service data flow recovered by the service de-mapping module, wherein,
• the service clock recovery module comprises a first buffering unit and a second buffering unit;
• the first buffering unit is configured to perform a homogenization treatment to the service data flow and then output to the second buffering unit;
• the second buffering unit is configured to output the service data flow according to the service clock after receiving the service data flow after the homogenization treatment;
• wherein,
• the service clock recovery module further comprises a data reading control unit;
• the data reading control unit is configured to generate a reading enabling signal, and control a reading operation of the first buffering unit by using the reading enabling signal;
• wherein, a preset value of a ratio of a number of clock cycles indicating that a reading signal is in an enabling status of the reading enabling signal to a total number of clock cycles of the reading enabling signal equals to a quotient of service clock frequency and OTN clock frequency;
• the data reading control unit is further configured to continually adjust the number of cycles indicating that the reading signal is in the enabling status of the reading enabling signal accordingly through judging whether status of the first buffering unit is empty or full;
• the first buffering unit is configured to read the service data flow into the present unit according to an OTN clock, reads out the service data flow from the present unit according to the OTN clock under control of the reading enabling signal and sends to the second buffering unit.