Method and system for synchronizing clock of transmission network as well as subordinate clock side entity

Abstract

The invention discloses a clock synchronization method in a transmission network, comprising the following steps: the time offset of VC12 bearing E1 corresponding to STM-N frame heads in STM-N frames and sent and received by master clocks and slave clocks is obtained by measuring the input and output time delay of the STM-N frames of each network element in SDH network in the directions from the master clocks to the slave clocks and from the slave clocks to the master clocks; the bidirectional delay inequality from the master clocks to the slave clocks and from the slave clocks to the master clocks is calculated according to the time offset; t1, t2, t3 and t4 are obtained from the interaction messages of the master clocks and the slave clocks; the offset is obtained by calculating the bidirectional delay inequality from the master clocks to the slave clocks and from the slave clocks to the master clocks and t1, t2, t3 and t4; and the clocks of the slave clocks are adjusted by itself according to the offset. The invention further discloses a corresponding system and a slave clock side entity. The offset can be accurately calculated by the method so as to ensure the synchronization between the master clocks and the slave clocks.

Description

technical field [0001] The present invention relates to the field of transmission network technology, in particular to a clock synchronization method and system in a transmission network and a slave clock side entity. Background technique [0002] The purpose of synchronization is to keep two or more signals consistent in time, specifically, to keep strictly consistent in frequency or phase. Clock synchronization methods include master-slave synchronization. In this way, the timing signal is transmitted from the master clock to the subordinate slave clock, and the slave clock adjusts its own clock according to the obtained timing signal to maintain synchronization with the master clock. [0003] In the clock synchronization method of a master-slave synchronization method in the prior art, the message sending process is as follows: figure 1 shown. It can be seen from the figure that Tm is the master clock, and Ts is the slave clock. The master clock and the slave clock are...

AI Technical Summary

Problems solved by technology

[0016] The object of the present invention is to provide a clock synchronization method, system and slave clock side entity in a transmission network, to overcome the shortcomings of inaccurate results and inability to guarantee clock synchronization by using a method similar to the IEEE1588 protocol to calculate Offset

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