Minimization of Spectrum Fragmentation for Improvement of the Quality of Service in Multifiber Elastic Optical Networks

Internet data traffic is still growing considerably in recent decades. In view of this exponential and dynamic growth, elastic optical networks are emerging as a promising solution for today's flexibly allocated bandwidth transmission technologies. The setup and release of dynamic connections with different spectrum bandwidths and data rates leads over time to spectrum fragmentation in the network. However, single-fiber eastic optical networks are faced with the problem of optical spectrum fragmentation. Spectrum fragmentation refers to small blocks, isolated, non-aligned spectrum segments which is a critical issue for elastic optical network researchers.With the advent of multifiber, this fragmentation ratio has become more pronounced, resulting in a high blocking ratio in multifiber elastic optical networks. In this paper, we propose a new routing and spectrum allocation algorithm to minimize fragmentation in multifiber elastic optical networks. In the first step, we define different virtual topologies as many as there is fiber, for each virtual topology, the k shortest paths are determined to find the candidate paths between the source and the destination according to the minimization of a proposed parameter called allocation cost. In the second step, we apply the resource allocation algorithm followed by the choice of the optimal path with a minimum energy cost. Blocking probability and spectrum utilization are used to evaluate the performance of our algorithm. Simulation results show the effectiveness of our proposed approach and algorithm.