Mapping wander in SONET/SDH fixed threshold and uniform pointer processors

There are three types of pointer processors in synchronous optical network (SONET) and synchronous digital hierarchy (SDH) networks: traditional fixed threshold pointer processors, adaptive threshold modulation pointer processors and uniform pointer processors. Fixed threshold pointer processors produce gapped pointer sequences, during SONET/SDH holdover mode, as a result of the periodic effects of the SONET/SDH overhead bytes. Uniform pointer processors can smooth the gapped pointer effects caused by the STM-1, AU and TU overhead bytes. However, uniform pointer processors can not remove the additional mapping wander caused by the VC overhead bytes. Mathematical analysis and simulation results, for fixed threshold pointer processors in SDH networks which use TU-3 to transport E3-rate PDH payloads in VC-3, illustrate the wander caused by the gapped pointer sequences. A proposed TU-3 uniform pointer processor algorithm shows the residual mapping wander caused by the VC-3 overhead bytes. These results can be extended to other combinations of PDH payloads and SONET/SDH virtual containers