IEEE 1588 defines a protocol, the Precision Time Protocol (PTP), that enables accurate synchronization over packet switched networks (PSN). Hardware timestamping of PTP event messages is key to achieving nanosecond synchronization accuracy for PTP slave clocks.
This white paper discusses Linux kernel support for IEEE 1588 hardware timestamping, including the precision time protocol (PTP) hardware clock (PHC) infrastructure, and the SO_TIMESTAMPING socket option. The PHC infrastructure and the SO_TIMESTAMPING socket option offer standardized APIs for user-space applications and Linux kernel device drivers. These kernel facilities improve device driver availability and simplify system integration.