This application provides a method for sending and receiving a clock synchronization packet in FlexE. The method includes: generating, by a sending apparatus, indication information and a plurality of data blocks, where the plurality of data blocks are obtained by encoding a first clock synchronization packet, the indication information is used to indicate a first data block, and the first data block is a data block used for timestamp sampling in the plurality of data blocks; determining, by the sending apparatus, according to the indication information, a moment at which the first data block arrives at a medium dependent interface MDI of the sending apparatus, and generating a sending timestamp, where the sending timestamp is used to record a sending moment of the first clock synchronization packet; generating a second clock synchronization packet carrying the sending timestamp; and sending, by the sending apparatus, the second clock synchronization packet.

A system and method for time stamp synchronization are disclosed. In one embodiment, first and second devices are provided. The second device receives a first time stamp of the first device, wherein the first time stamp was generated in response to a time stamp synchronization event common to the first and second devices; generates a second time stamp of the second device in response to the time stamp synchronization event, wherein the first and second time stamps are in different time domains; and correlates the first and second time stamps, wherein correlating the first and second time stamps provide a relationship between the time domains because the first and second time stamps were both generated with respect to the same time stamp synchronization event common to the first and second devices.

This application provides a data transmission method in an optical network and an optical network device. The method includes: obtaining, by a first device, first synchronization information from a first service data stream, and determining a to-be-transmitted service data stream; generating second synchronization information based on the first synchronization information; mapping the second synchronization information and the to-be-transmitted service data stream to an optical carrier container; and sending the optical carrier container. A second device receives the optical carrier container; obtains a second service data stream and third synchronization information from the optical carrier container through demapping; generates fourth synchronization information based on the third synchronization information; and inserts the fourth synchronization information into the second service data stream, to obtain a third service data stream. In this way, time synchronization precision is improved.

Time stamp replication within wireless networks is described. In an embodiment, a wireless station receives an input time stamp and uses this input time stamp to generate an output time stamp. The wireless station transmits the output time stamp to wireless stations in one of a number of groups which make up the wireless network. The output time stamp is generated to compensate for delays between receiving the input time stamp and transmitting the output time stamp such that output time stamp which is transmitted at a time T corresponds to the value that the input time stamp would have had if it had been received at time T (and not at a time earlier than T). This may, therefore, reduce or eliminate independent time stamp errors and jitter caused by multiple disparate systems and processes.

A system and method for time stamp synchronization are disclosed. In one embodiment, first and second devices are provided. The second device receives a first time stamp of the first device, wherein the first time stamp was generated in response to a time stamp synchronization event common to the first and second devices; generates a second time stamp of the second device in response to the time stamp synchronization event, wherein the first and second time stamps are in different time domains; and correlates the first and second time stamps, wherein correlating the first and second time stamps provide a relationship between the time domains because the first and second time stamps were both generated with respect to the same time stamp synchronization event common to the first and second devices.

Time transfer systems and methods in Flexible Ethernet (FlexE) include, in a node supporting Flexible Ethernet (FlexE), communicating a FlexE group with an adjacent node via a FlexE shim; providing a synchronization message channel to the adjacent node via overhead of the FlexE shim for the FlexE group; and exchanging synchronization messages via the synchronization message channel with the adjacent node. The synchronization messages can be Precision Time Protocol (PTP) messages. A timestamp point for a synchronization message can be a start of a FlexE frame or multi-frame boundary.

A baseline difference is determined between a slave line card time stamp corresponding to a slave line card frame sync signal and a master line card time stamp corresponding to a master line card frame sync signal. The slave line card generates subsequent slave line card time stamps for subsequent slave line card frame sync signals and the master line card generates subsequent master line card time stamps for subsequent master line card frame sync signals. Current differences are determined between subsequent slave line card time stamps and the subsequent master line card time stamps and the current differences are compared to the baseline difference. When a mismatch difference occurs (current difference differs from the baseline difference), the mismatch difference causes a phase-locked loop in the master line card to be adjusted or an offset to be provided to the master line card time of day counter.

An operation method of a first communication node in an Ethernet-based vehicle network includes identifying a link status between the first communication node and each of a plurality of communication nodes included in the vehicle network; receiving a first frame from a second communication node whose link status is normal among the plurality of communication nodes; identifying a first time difference between a local time of the first communication node and a time stamp of the first frame; and determining a synchronization error between the first communication node and the second communication node based on the first time difference.

Provided are a synchronization method, a wide area system protection apparatus, a plant station and a computer readable storage medium. The method includes: sending to a second plant station a first data frame that includes a sequence number p and a sending timestamp of the first data frame; receiving a second data frame sent by the second plant station, and recording a receiving timestamp of the second data frame, the second data frame including a sequence number q of the second data frame, a sending timestamp of the second data frame and a receiving timestamp of the first data frame, and the first data frame being adjacent to the second frame on the second plant station; calculating a time phase difference and a crystal oscillator frequency deviation between the first plant station and the second plant station; and adjusting time and a clock frequency of the first plant station.

Systems and methods of compensating for the delay asymmetry of coherent optical modems in a packet optical network include measuring fill levels of one or more queues each including an elastic First-In-First-Out (FIFO) circuit used in a transport mapping scheme, wherein the transport mapping scheme is one or more of client mapping to Optical Transport Unit (OTU) and OTU mapping to Flexible OTN (FlexO); and performing adjustments in a clock based in part on the measured fill levels, wherein the adjustments are configured to reduce a Time Error (TE) in the packet network based on delay asymmetry between two nodes.