Protocols and time transfer
Synchronous EthernetSyncE
Synchronous Ethernet (SyncE) distributes a stable frequency via the bit clock of the Ethernet physical layer, independent of the data traffic packets. This keeps the frequency in a network synchronised even under heavy load.
SyncE provides frequency (not time-of-day) and is often combined with PTP, which provides the time; together they form the basis of telecom timing.