Protected Working Lightpath Envelope: a New Paradigm for Dynamic Survivable Routing

We propose a new scheme, called protected working lightpath envelope (PWLE), for dynamic provisioning of survivable services without requiring any wavelength conversion. PWLE is a path-oriented protection strategy based on lightpath-protecting rho-cycles. It partitions the total network capacity into a static protection layer and a working layer available for dynamic routing. To deal with the new issues raised by lightpath-protecting p-Cycles, we propose compatible grouping so that the PWLE can be formulated as an mixed integer linear programming (MILP) model. Based on compatible grouping, we further propose compatible group routing (CGR), a distributed routing algorithm tailored for PWLE. Compared with rho-Cycle-based protected working capacity envelope (PWCE), PWLE has the advantages of high capacity efficiency, avoidance of wavelength conversion, good blocking performance and guaranteed optical transmission quality. We evaluate the performance improvement of PWLE in capacity efficiency and blocking performance through the numerical results obtained from CPLEX and simulations.