Simulated Annealing Algorithm for Minimization of Bandwidth Fragmentation in Elastic Optical Networks with Multicast and Unicast Flows

The recently proposed idea of Elastic Optical Networks (EON) is expected to largely improve performance of optical networks in terms of resource utilization. However, the possibility to divide the optical spectrum into relatively narrow segments called slices in EONs triggers the problem of bandwidth fragmentation. In this paper, we propose a novel metaheuristic algorithm based on the Simulated Annealing approach to solve the Routing and Spectrum Assignment (RSA) problem with the objective function denoting the bandwidth fragmentation. It is assumed that two types of network flows are optimized, namely, multicast and unicast. Using two representative network topologies, we run extensive numerical experiments to tune the SA algorithm and verify its performance in various scenarios. The main conclusion is that the application of our SA algorithm can significantly improve the bandwidth fragmentation in EONs.