Clock synchronization system using the packet filter device, method and program

The clock synchronization system for synchronizing the clock of the slave node to the master node clock not properly perform packet filtering can not be synchronized. The master node comprises a packet sending means for sending time stamps the packet containing the (TS) to the slave node. Slave node calculates a packet receiving means for receiving a packet transmitted from the master node, a difference between the TS packet and the received TS clock of the slave node at the time of packet reception as the value of the delay of a packet, the packet correcting the threshold value for delay value or the packet delay, the packet received from the packet receiving means, a packet filter means for performing filtering processing based on the threshold for the delay of the delay values ​​and the packets having the packet was adopted packets based on the TS included in and a phase synchronization means for outputting a clock of the slave node.