The frequency holdover or partial holdover function is an example of how frequency references could be used in phase & time synchronization. This Net.Time feature provides nanosecond accuracy for a long time when GNSS or PTP references are lost.

The accuracy of a watch depends on the application. Anyone who wants to catch a train has to have an eye on the minutes. In competitive sport, a hundredth of a second can be decisive and a packaging machine may need microsecond accuracy.

This paper reviews techniques of frequency and phase distribution by means of packet networks that require new synchronization architectures. PTP is the key technology for those applications requiring an accuracy of micrfoseconds.

This presentation is a course that offers a methodology for the installation of new protocols based on IEC-61850 such as PTP and its interconnection with legacy signals such as IRIG-B.