Patent ID: 7058020

Claim:
A system for time-stamping a data packet associated with a data network, comprising: a network media interface device for transferring an IP packet to or from a network medium; a time source for generating and maintaining a time code; a time stamping circuit for sampling a time code from the time source when the interface device transfers the IP packet to the network medium from a software layer or from the network medium to the software layer, and for associating the time code with the IP packet so as to form a time stamped IP packet; an application software package for receiving a pair of time-stamped IP packets from the time stamping circuit, and for calculating a time difference therefrom; wherein each of the time-stamped IP packets includes at least a portion of the time code in a CRC field of the IP packet; and wherein for each of the time-stamped IP packets, the time-stamping circuit (i) executes a CRC calculation on the IP packet so as to produce a single error bit signifying whether or not an error is present in the IP packet, (ii) removes as an original CRC word from the CRC field of the IP packet, and (iii) inserts the error bit and the time code into the CRC field of the IP packet.