Patent ID: 7720109

Claim:
A method of estimating a one-way delay time between first and second hosts connected to a network and communicating a predetermined packet, the method comprising: measuring k-th, (k+1)-th, and (k+2)-th transmission times of the packet at the first host, using a clock of the first host, and measuring k-th, and (k+1)-th transmission times of the packet at the second host, using a clock of the second host; calculating a time difference between the m-th transmission time measured at the first host and the m-th transmission time measured at the second host, where m is k or k+1; using one or more of the measured transmission times, to calculate k-th and (k+1)-th round-trip delay times at the first host, and a k-th round-trip delay time at the second host; calculating one or more m-th one-way delay times, using the round-trip delay times; determining whether the calculated time difference is identical to the calculated one-way delay times; and when the calculated time difference is determined to be identical to the calculated one-way delay times, determining a value equal to or less than the calculated one-way delay times, as the estimated one-way delay time; and synchronizing the clocks of the first and second hosts using the estimated one-way delay time.