IEEE 1588 Precision Time Protocol
IEEE 1588 is a network-based protocol called Precision Time Protocol (PTP) or, more fully, the IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems. That is, it uses exclusively the IT network infrastructure and requires no additional cabling to function. In this sense it is a development of NTP Network Time Protocol but now with the right level of precision and footprint for automation and other demanding environments like printing machines or fly-by-wire aircraft with predominantly embedded or less-powerful systems. Precision of +/- 5ns is possible.