Patent ID: 7768931

Claim:
A network environment, comprising: a master computer; and a slave computer coupled to the master computer by a communication network, wherein the slave computer comprises: a real time clock; a memory containing a time drift measurement program; and a processor which, when executing the time drift measurement program, performs an operation comprising: calculating a first time drift value between the real time clock of the slave computer and a real time clock of the master computer, wherein the first time drift value is based on a first real time indicating when the slave computer receives a first packet, a second real time indicating when the master computer transmits the first packet, and a first propagation time indicating an amount of time for the first packet to travel from the master computer to the slave computer; calculating a second time drift value between the real time clock of the slave computer and the real time clock of the master computer, wherein the second time drift value is based on a third real time indicating when the slave computer sends a second packet, a fourth real time indicating when the master computer receives the second packet, and a second propagation time indicating an amount of time for the second packet to travel from the slave computer to the master computer; calculating an average time drift value between the real time clock of the slave computer and the real time clock of the master computer using the first time drift value and the second time drift value; and adjusting the real time clock using the average time drift value.