A new approach to optimization of p-cycle protected Multicast optical networks

This paper provides a new approach to protection of multicast transmissions in optical networks. Namely, we introduce an enhanced version of p-cycles called Multicast Protecting p-Cycle (MPpC) designed to protect multicast flows and propose a new ILP (Integer Linear Program) formulation enabling a joint optimization of working and spare capacity in optical networks protected by MPpCs. In contrast to a classic protection p-cycle (CPpC) concept, which is limited only to the protection of individual links, the MPpC idea assumes protection of the whole multicast tree on end-to-end basis. Therefore, applying the MPpCs provides significant improvement in terms of the capacity efficiency when compared to CPpCs. To our best survey, this is the first study that formulates the joint working and spare capacity optimization in multicast optical networks protected by p-cycles with additional multicast-oriented capabilities. Due to the high complexity and memory requirements of the ILP formulation, we also present an effective heuristic algorithm based on the Simulation Annealing approach. Results of numerical experiments confirm that the MPpC approach outperforms classic p-cycles, i.e., MPpCs provide from 12% to 31% of capacity cost savings depending on the network topology and p-cycle generator.