Patent ID: 7630357

Claim:
A method for synchronizing operation of distributed cable modem termination system components, the method comprising: transmitting a plurality of data packets from a head end to a downstream transmitter hub via a packet data network, each data packet marked with a measured delay Quality of Service (QoS) indicator and including a time stamp based upon a clock of the head end and a delay tag corresponding to a delay in traversing the packet data network between the head end and the downstream transmitter hub; receiving the plurality of data packets at the downstream transmitter hub; within the downstream transmitter hub, smoothing the time stamps of the plurality of data packets received by the downstream transmitter hub based upon corresponding delay tags of the plurality of data packets; based upon the smoothed time stamps, synchronizing a clock of the downstream transmitter hub with the clock of the head end; and synchronizing a clock of an upstream receiver hub with the clock of the downstream transmitter hub.