Title: Timing and synchronization aspects in packet networks
Summary
Defines ESMC (Ethernet Synchronization Message Channel) to carry SSM messages
Defines functional models for SyncE and Circuit Emulation synchronization
Status
- Current version: 3rd. Edition, August 2017, plus Amendment 1, March 2018
- Download from: http://www.itu.int/ITU-T/recommendations/rec.aspx?rec=13321
Key Contents
- Definition of ESMC:
- ESMC based on Ethernet Link OAM using the Organizational Specific Slow Protocol (OSSP)
- Carries 4-bit SSM code defining Quality Level (QL) (codes defined in G.781)
- “Heart-beat” frame sent once per second
- Event frame sent on QL-change
- Link declared down after 5s without receiving a heartbeat frame
- Use of SyncE in a multi-operator context
