Patent ID: 7990909

Claim:
A method of achieving frequency synchronization between a first clock at a first node and a second clock at a second node of a packet-carrying communications network, the method comprising: measuring, at the first node, a property of packet transmission through the network between the first node and the second node; sending the measurement of the property from the first node to the second node; measuring, at the second node, the same property of packet transmission through the network; using, at the second node, the measurement of the property made at the first node and the measurement of the property made at the second node to synchronize the frequency of the second clock with respect to the first clock; and repeating the measuring at the first node, sending the measurement at the first node to the second node, measuring at the second node, and using the measurements at the second node to synchronize the frequency until a difference between the measurement at the first node and the measurement at the second node is less than a predetermined amount.