IEEE 802.1AS-2020IEEE Standard for Local and Metropolitan Area Networks--Timing and Synchronization for Time-Sensitive Applications

Protocols, procedures, and managed objects for the transport of timing over local area networks are defined in this standard. 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).