Patent ID: 7366774
Filing Date: 2008-04-29
Classification: H04L

Abstract:
1. A method of detecting excessive network delay in a high reliability communications system composed of a network carrying messages between at least a first and second node, the first and second nodes having first and second unsynchronized clocks respectively, the method comprising the steps of: (a) transmitting a current first time of the first clock over the network from the first node to the second node; (b) comparing the first time to a current second time of the second clock upon receipt of the first time value, to deduce an offset; (c) transmitting, at an arbitrary time after step (a), the offset and a current third time of the second clock over the network from the second node to the first node; and (d) comparing the offset and third time to a current fourth time of the first clock to reveal a network delay value.