Patent ID: 7394802

Claim:
A network synchronization system comprising: an NTP (Network Time Protocol) server for providing time synchronization to a plurality of node units in the network, the NTP server comprising a synchronous mobile terminal as a reference clock to provide time synchronization to the node units in the network, the synchronous mobile terminal being present in the network area and having a wireless interface and a virtual clock manager in communication with the mobile terminal through the wireless interface to manage the mobile terminal as a virtual reference clock, the virtual clock manager comprises a clock manager for managing mobile terminals present in the network area and operated as the reference clock of the NTP server, wherein the clock manager manages the mobile terminals hierarchically using previously input information of each mobile terminal, the information including a unit number, authentication information, or priority as a clock reference source, and upon the NTP server receiving a time information request, the clock manager acquires the time information from an uppermost mobile terminal in response to the request.