The principle of G.8275.1 time synchronization is the same as the principle of the IEEE 1588v2. The master and slave nodes send and receive timing messages of each other. According to the receiving and sending timestamps in the timing messages, the total delay in bidirectional transmission between nodes can be calculated. If the bidirectional delays are the same, the total delay divided 2 is equal to the unidirectional delay, which is the time difference between the slave node and the master node. Then, the slave node corrects the local time according to the time difference. In this manner, the slave node is synchronized with the master node.