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.