Patent ID: 8730868

Claim:
A network node for transferring data in a network, comprising: a network interface having a plurality of ports; a transfer control module; a time synchronizing module; a fluctuation measurement module; and a clock, wherein: the time synchronization module uses a received time synchronization packet to synchronize the clock; the fluctuation measurement module determines an accuracy of a time contained in the received time synchronization packet based on a result of comparison between the time contained in the received time synchronization packet and a time of the clock; the time synchronization module is configured to: correct the time of the clock with the time contained in the received time synchronization packet, and obtain a correction amount of the time of the clock; the fluctuation measurement module is configured to: determine whether a network node of a synchronization source is to be changed based on a result of comparison between a result of statistically processing the correction amount obtained by the time synchronization module and a predetermined threshold, and determine whether there is another network node of a synchronization source depending on whether a time synchronization packet transmitted from a network node other than a current synchronization source is received; and the time synchronization module ignores a synchronization signal transmitted from the network node of the current synchronization source, and starts processing for synchronization with a network node of a new synchronization source based on results of the determinations by the fluctuation measurement module.