# US 2018/0026735 A1 · Method, device, system, and storage medium for implementing time synchronization in optical transport network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0026735 A1 - Document ID: US20180026735A1 - Status: Published application - Kind: A1 - Application number: 15/543,386 - Filed: 2015-07-14 - Published: 2018-01-25 - Earliest claimed: 2015-01-16 - Applicants: Sanechips Technology Co., Ltd. - Inventors: Zongzheng Chen - Web page: https://patentgrep.com/patent/US20180026735A1 ## CPC - H04J 3/0667: {Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays (arrangements for monitoring round trip delays in packet switching networks H04L43/0864)} - H04J 3/065: {using timestamps} - H04J 3/067: {Details of the timestamp structure} - H04L 7/00: Arrangements for synchronising receiver with transmitter {(synchronisation of generators of electric oscillations or pulses H03L7/00)} - H04J 2203/0085: Support of Ethernet - H04J 2203/0089: Multiplexing, e.g. coding, scrambling, SONET - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A master device generates a time synchronization message, performs a first correction on a correction domain of the time synchronization message, and sends it including a first timestamp T1 to a slave device. The slave device performs a second correction on the correction domain of the time synchronization message, adds a second timestamp T2, generates a delay request message, performs a third correction on the correction domain of the delay request message, and sends to the master device the delay request message including a third timestamp T3. The master device performs a fourth correction on the correction domain of the delay request message, adds a fourth timestamp T4, sends to the slave device a delay response message including the correction domain of the delay request message subjected to the fourth correction and the fourth timestamp T4. The slave device performs time synchronization with the master device accordingly. ## Claims ### Claim 1 A method for implementing time synchronization in an Optical Transport Network (OTN), comprising: generating, by a master device, a time synchronization message, performing a first correction on a correction domain of the time synchronization message, and sending to a slave device the time synchronization message including a first timestamp T1; and receiving, by the master device, a delay request message which has been subjected to a third correction and includes a third timestamp T3, performing a fourth correction on a correction domain of the delay request message, adding a fourth timestamp T4 to the delay request message, and sending to the slave device a delay response message including the fourth timestamp T4 and the correction domain of the delay request message which has been subjected to the fourth correction. ### Claim 2 (depends on 1) The method according to claim 1, wherein generating, by the master device, the time synchronization message, performing the first correction on the correction domain of the time synchronization message, and sending to the slave device the time synchronization message including the first timestamp T1 comprises: the master device comprises a first time synchronization device and a first service transport device, wherein the first time synchronization device generates the time synchronization message, writes into the time synchronization message the first timestamp T1 at which the time synchronization message is generated, and adds to the 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 service transport device receives the time synchronization message from the first time synchronization device, adds, 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 sends the time synchronization message out. ### Claim 3 (depends on 2) The method according to claim 2, wherein performing the fourth correction on the correction domain of the delay request message, adding the fourth timestamp T4 to the delay request message, and sending to the slave device the delay response message including the correction domain of the delay request message on which the fourth correction has been performed and including the fourth timestamp T4 comprises: sending, by the first service transport device, 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; and determining, by the first time synchronization device, local counting time t4 at which the delay request message is received, adding a difference value between t4 and t3 to the correction domain of the delay request message, generating the delay response message, adding to the delay response message the fourth timestamp T4 at which the delay response message is generated and the correction domain of the delay request message, and sending the delay response message to the slave device through the first service transport device. ### Claim 4 (depends on 1) The method according to claim 1, wherein sending the time synchronization message to the slave device comprises: inserting the time synchronization message into reserved overhead of an OTN frame after encapsulating the time synchronization message by a Generic Framing Procedure-Framed (GFP-F), and sending the time synchronization message to the slave device through the OTN frame. ### Claim 5 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. ### Claim 6 (depends on 5) The method according to claim 5, wherein receiving, by the slave device, the time synchronization message which has been subjected to the first correction and includes the first timestamp T1, performing the second correction on the correction domain of the time synchronization message, and adding the second timestamp T2 to the time synchronization message comprises: the slave device comprises a second time synchronization device and a second service transport device, wherein the second service transport device receives the time synchronization message which has been subjected to the first correction and includes the first timestamp T1, and sends 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 time synchronization device determines local counting time t6 at which the time synchronization message is received, adds a difference value between t6 and t5 to the correction domain of the time synchronization message, and adds to the time synchronization message the second timestamp T2 at which the time synchronization message is received. ### Claim 7 (depends on 6) The method according to claim 6, wherein generating, by the slave device, the delay request message, performing the third correction on the correction domain of the delay request message, and sending to the master device the delay request message including the third timestamp T3 comprises: generating, by the second time synchronization device, the delay request message, writing into the delay request message the third timestamp T3 at which the delay request message is generated, and adding 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 receiving, by the second service transport device, the delay request message from the second time synchronization device, adding local counting time t8 at which the delay request message exits from the second service transport device to the correction domain of the time synchronization message, and sending the delay request message out. ### Claim 8 (canceled) ### Claim 9 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. ### Claim 10 (depends on 9) The master device according to claim 9, wherein the first time synchronization device and the first service transport device each comprises a local time counter; the local time counter of the first time synchronization device is arranged to generate the local counting time t1 and the local counting time t4, and the local time counter of the first service transport device is arranged to generate the local counting time t2 and the local counting time t3. ### Claim 11 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. ### Claim 12 (depends on 11) The slave device according to claim 11, wherein the second time synchronization device and the second service transport device each comprises a local time counter; the local time counter of the second time synchronization device is arranged to generate the local counting time t6 and the local counting time t7, and the local time counter of the second service transport device is arranged to the local counting time t5 and the local counting time t8. ### Claim 13 (canceled) ### Claim 14 (depends on 1) A computer storage medium, having stored therein computer executable instructions for implementing a method according to claim 1. ### Claim 15 (depends on 5) A computer storage medium, having stored therein computer executable instructions for implementing a method according to claim 5.