Method, device, system, and storage medium for implementing time synchronization in optical transport network

A method for implementing time synchronization in an Optical Transport Network (OTN), comprising:

• receiving, by a slave device, a time synchronization message which has been subjected to a first correction and includes a first timestamp T1, performing a second correction on a correction domain of the time synchronization message, and adding a second timestamp T2 to the time synchronization message;
• generating, by the slave device, a delay request message, performing a third correction on a correction domain of the delay request message, and sending to a master device the delay request message including a third timestamp T3;
• receiving, by the slave device, a delay response message including a fourth timestamp T4 and the correction domain of the delay request message which has been subjected to a fourth correction;
• and
• performing, by the slave device, time synchronization with the master device according to the T1, the T2, the T3, the T4, the correction domain of the time synchronization message and the correction domain of the delay request message.

A master device, comprising:

• a first time synchronization device and a first service transport device, wherein
• the first time synchronization device is arranged to generate a time synchronization message, write into the time synchronization message a first timestamp T1 at which the time synchronization message is generated, and add to a correction domain of the time synchronization message a complement of local counting time t1 at which the time synchronization message exits from the first time synchronization device;
• the first time synchronization device is further arranged to determine local counting time t4 at which a delay request message is received, add to a correction domain of the delay request message a difference value between t4 and local counting time t3 at which the first service transport device receives the delay request message, generate a delay response message, add a fourth timestamp T4 at which the delay response message is generated and the correction domain of the delay request message to the delay response message, and send the delay response message to a slave device through the first service transport device;
• and
• the first service transport device is arranged to receive the time synchronization message from the first time synchronization device, add, to the correction domain of the time synchronization message, local counting time t2 at which the time synchronization message exits from the first service transport device, and send the time synchronization message out;
• the first service transport device is further arranged to receive the time synchronization message which has been subjected to a correction performed by the slave device and includes a third timestamp T3, and send the local counting time t3 at which the delay request message is received as well as the delay request message to the first time synchronization device.

A slave device, comprising:

• a second time synchronization device and a second service transport device;
• wherein
• the second service transport device is arranged to receive a time synchronization message which has been subjected to a correction performed by a master device and includes a first timestamp T1, send local counting time t5 at which the time synchronization message is received as well as the time synchronization message to the second time synchronization device;
• the second service transport device is further arranged to receive a delay request message from the second time synchronization device, add local counting time t8 at which the delay request message exits from the second service transport device to a correction domain of the time synchronization message, send the delay request message out, and receive a delay response message including a fourth timestamp T4 and a correction domain of the delay request message which has been subjected to a correction performed by the master device;
• and
• the second time synchronization device is arranged to determine local counting time t6 at which the time synchronization message is received, add a difference value between t6 and t5 to the correction domain of the time synchronization message, and add to the time synchronization message a second timestamp T2 at which the time synchronization message is received;
• the second time synchronization device is further arranged to generate the delay request message, write into the delay request message a third timestamp T3 at which the delay request message is generated, add a complement of local counting time t7 at which the delay request message exits from the second time synchronization device to the correction domain of the delay request message, and perform time synchronization with the master device according to the T1, the T2, the T3, the T4, the correction domain of the time synchronization message and the correction domain of the delay request message.