Abstract: A system for time-stamping a data packet associated with a data network allows software applications, running on non-deterministic systems, to determine the precise time that packets were transmitted to or received from a physical network interface. The system includes a network media interface device for transferring a data packet to or from a network medium, and a time source for generating and maintaining a time code. The system further includes a time-stamping circuit for sampling a time code from the time source when the interface device transfers the data packet to or from the network medium, and for associating the time code with the receive data packet so as to form a time-stamped packet.