LCAS and GFP for service protection in next generation SONET/SDH

Automatic protection switching (APS) is a mechanism adopted by SONET/SDH to automatically relocate traffic from a high priority path to a path assigned for protection. Although this method is created to respond to failures and reestablish the service in less than 50ms, it does not address issues related to low priority traffic, which in case of a failure is simply lost. The generic framing procedure (GFP) and the link capacity adjustment scheme (LCAS) are new procedures included in the next generation SONET/SDH which along with automatic protection switching (APS) provides service protection solutions to both high and low priority traffic. This paper provides an overview of these technologies and explains the implementation of GFP and LCAS for alternative service protection on the next generation SONET/SDH.