System Architectures for Timing Transfer over PDH and SDH Transmission Networks

In this paper, system architectures for point-to-point timing transfer over PDH and SDH transmission networks are detailed and discussed. First, it is pointed out that PDH transmission networks do not need to be synchronized, while they feature good timing transparency on transported tributaries. Then, schemes for point-to-point timing transfer over PDH and SDH transmission systems are discussed. The impact of modern network synchronization facilities including building clocks is also considered. The advantages of the SDH-based scheme with respect to the PDH-based scheme are highlighted. In conclusion, this paper provides a comprehensive and up-to-date overview on effective timing transfer architectures for synchronization distribution in modern digital networks, enabling the synchronization system engineer to implement the best technological solutions nowadays available.