Method for precision time protocol synchronization network and apparatus

A slave clock apparatus, comprising:

• an executing unit, configured to execute an operation of time synchronization with a first apparatus according to Precision Time Protocol (PTP) through a first port, wherein the first apparatus is an upstream node of the slave clock apparatus, the first apparatus is located on a first link, a link from a master clock apparatus to the slave clock apparatus comprises the first link and a second link, the slave clock apparatus comprises the first port and a second port, the first port is located on the first link, the second port is located on the second link, a state of the first port is slave, and a state of the second port is passive;
• a setting unit, configured to set the state of the second port to slave;
• a first determining unit, configured to obtain, according to the PTP through the second port, information required for determining a time offset between the slave clock apparatus and a second apparatus, wherein the second apparatus is an upstream node of the slave clock apparatus, and the second apparatus is located on the second link;
• and
• a second determining unit, configured to determine an offset according to the information obtained by the first determining unit, wherein the offset is equal to M multiplied by the time offset, and M is not equal to 0.