Optimization of Extended p-Cycle Protection in Mixed Line Rate WDM Networks with Limited Transmission Reaches

We consider the problem of routing and rate assignment with extended p-cycle protection for mixed line rate (MLR) networks that are limited by transmission reaches. The problem is formulated mathematically as an integer linear programming (ILP) problem under the assumption that allows each p-cycle to protect working lightpaths with various transmission rates. The objective of ILP is to minimize the overall cost function, which consists of transponder operating costs as primary costs and pcycle operating costs as secondary costs. We perform a comparative study between extended pcycle and conventional p-cycle approaches. Numerical results demonstrate that the extended pcycle approach yields lower costs and is more efficient for network protection than conventional pcycle protection .