SDH Multiplexing

SDH Multiplexing Structure


1. Mapping

   A process used when tributaries are adapted into VCs by adding justification bits and POH information

2. Aligning

   This process takes place when a pointer is included in a Tributary Unit (TU) or an Administrative Unit (AU), to allow the 1st byte of the VC to be located

3. Multiplexing

   This process is used when multiple low-order path signals are adapted into a higher-order path signal, or when high-order path signals are adapted into a Multiplex Section

4. Stuffing

   As the tributary signals are multiplexed and aligned, some spare capacity has been designed into the SDH frame to provide enough space for all various tributary rates.Therefore, at certain points in the multiplexing hierarchy, this space capacity is filled with “fixed stuffing” bits that carry no information, but are required to fill up the particular frame


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