Patent ID: 8274891

Claim:
A method for time calibration in nodes of a network utilizing characterizations of multiple disparate communication paths across the network which vary in transmission behavior frequently over time, the method comprising: sending from a peer node a plurality of request messages to a network control point (NCP) over a first plurality of communication paths, wherein the request messages are each tagged with a send time according to a peer node clock in the peer node; selecting a first request message received in the NCP and tagged with an arrival time by a master clock in the NCP; sending from the NCP in response to the first request message a plurality of reply messages to the peer node over a second plurality of communication paths, wherein the reply messages are each tagged with a reply send time according to the master clock in the NCP, wherein the reply messages each include the send time; selecting a first reply message received in the peer node and tagged with a reply arrival time according to the peer node clock; and calibrating a network time at the peer node to the master clock in the NCP based on the send time according to the peer node clock, the reply send time according to the master clock in the NCP, and the reply arrival time according to the peer node clock, wherein the calibrating comprises: generating a ratio of an average reply send time versus an average reply arrival time for a plurality of samples of the reply send time and a plurality of samples of the reply arrival time; and generating the network time at the peer node based on an evaluation of a function of the ratio, current time at the peer node, and a round trip time.