Protection scheme for VCAT/LCAS on SONET/SDH networks with virtual paths switchable between active and standby states

摘要

Virtual Concatenation (V CAT) and Link Capacity Adjustment Scheme (LCAS) are used to transport large data streams across SONET (Synchronous Optical NETwork) and SDH (Synchronous Digital Hierarchy) systems. Redundancy is provided by specifying working paths and protection paths within a Virtual Concatenation Group (VCG) whose total bandwidth exceeds that which must be transported. Traffic may be spread across both working and protection paths and any failed path is dropped from the VCG, reducing total bandwidth. In the invention protection paths are kept on standby and only activated when a working path fails, additionally failed paths are not dropped from the VCG.