Overview
As per the requirements in packet based networks, ITU-T SG15/Q13 defines the timing and synchronization characteristics in G.8261 recommendations, proposes the concept of Synchronous Ethernet (SyncE), and defines the performance requirements of synchronous Ethernet Equipment Clock (EEC) and Enhanced Synchronous Ethernet Clock in G.8262 and G.8262.1 recommendations.
Fig 1 Pull-in/Hold-in/Pull-out Measurements