Multiplexing

Multiplexing

Multiplexing

PDH

Multiplexing

•Plesiochronous digital hierarchy (PDH)-each TDM stream was derived using a separate timing source-Justification bits

•Synchronous digital hierarchy (SDH)-all equipment is synchronized to a single master clock-Synchronous transport module level 1 or STM-1 is 155.52Mbps-A section is a single length of transmission cable-Section Termination equipment (STE) : repeater-A Line extends across multiple cable sections and is terminated by a line termination equipment (LTE) -> multiplexers and switching nodes-A path is an end-to-end transmission path through the complete transmission system-Each frame comprises 2430 bytes and repeats every 125 microsec.-A frame comprises nine 270-byte segments each of which has a 9-byte header associated with it and a 261-byte payload