Evaluation of timestamping uncertainty in a software-based IEEE1588 implementation

The IEEE1588 became in the last years the de-facto solution to obtain a strict synchronization over a local area network. The purpose of the paper is to analyze the uncertainty sources that affect a software-only implementation of the IEEE1588 (the so called PTPd) based on off-the-shelf PC components. A careful analysis of timestamp mechanism and time management in a PC platform with an Operating System is carried out. The experimental setup presented in the paper highlights that the main uncertainty source of a software-only synchronization approach is the timestamp method. At the end of the paper, an index to evaluate the Timestamping uncertainty, called Timestamping Uncertainty Index (TUI) has been proposed and applied to the test case presented.