ISO/IEC/IEEE International Standard for Information technology -- Telecommunications and information exchange between systems -- Local and metropolitan area networks -- Part 1AS: Timing and synchronization for time-sensitive applications in bridged local area networks

This standard defines a protocol and procedures for the transport of timing over bridged and virtual bridged local area networks. It includes the transport of synchronized time, the selection of the timing source (i.e., best master), and the indication of the occurrence and magnitude of timing impairments (i.e., phase and frequency discontinuities).