Redundancy, Restorability and Path Availability in Optical Mesh Networks

A new calculation method to estimate path availability under dual failure scenarios for networks designed for 100% restorability against single span failures is presented. This method is applicable to all survivability schemes and considers their respective restoration or protection effect. A case study calculates the availability of all service paths within a long haul network under four protection/restoration strategies: dedicated automatic protection switching, shared backup path protection, span restoration and protection-cycles. The availability optimization potential is estimated based on measures for standard network redundancy and dual failure restorability. Assets and drawbacks of survivability schemes are compared from the availability and capacity efficiency point of view