A protection and fragmentation management approach in elastic optical networks under multicast traffic

Elastic Optical Networks (EONs) support the flexible allocation of bandwidth and contribute to high-speed all-optical data communications. Any traffic demand passing through optical fibers is susceptible to link failure, which may lead to tremendous data and revenue loss. Another serious concern related to spectrum allocation in EONs is fragmentation, which is the problem of not being able to use free spectrum blocks because of misalignment. To provide survivability to the multicast traffic demands and also manage the problem of fragmentation in EONs, we propose an approach that integrates multicast light-tree protection using a dedicated protection approach and three policies of spectrum allocation to manage fragmentation in EONs. We have also considered a traffic grooming based approach along with the proposed approach. Grooming of traffic demands means routing similar traffic demands through a common light-tree and allocating spectrum to the links of the light-tree according to the cumulative bandwidth demand of the groomed traffic. The simulation results performed on several network topologies indicate that our proposed approach outperforms existing approaches concerning bandwidth blocking probability and fragmentation index.