scope:

This Technical Report (TR) addresses synchronization issues in packet networks including timing distribution, network element timing requirements, and possible mechanisms for timing transfer. The report looks at the carriage of TDM-type services over a packet transport infrastructure. This TR covers different packet transport technologies including IP, MPLS, ATM, Ethernet, xDSL, and PON. The document addresses several areas including service requirements, common approaches employed in the industry, and a description of techniques specific to certain packet transport technologies. This document also describes emerging technologies -- e.g., Synchronous Ethernet -- that are currently being studied at ATIS and the ITU-T.