An Efficient IA-RMLSA Algorithm for Transparent Elastic Optical Networks

Abstract

This paper proposes a new Routing, Modulation Level and Spectrum Assignment (RMLSA) algorithm that considers the effects of physical layer in transparent elastic optical networks. The goal of the algorithm is to reduce the circuit blocking probability caused by the transmission quality degradation in the establishment of new circuits. The proposed algorithm is compared with two other Impairment-Aware RMLSA (IA-RMLSA) algorithms: Modified Dijkstra Path Computation (MD-PC) and K-Shortest Path Computation (KS-PC). The IA-RMLSA algorithms are evaluated under three different composition of bandwidth request for EON and NSFNet network topologies. Besides, we also evaluated the performance of IA-RMLSA algorithms using First-Fit and Best-Fit to spectrum assignment. Simulation results show that the proposed algorithm exhibits better performance than the MD-PC and KS-PC algorithms with regard to i) the circuit blocking probability, ii) the bandwidth blocking probability, iii) the fairness of service to different source-destination pairs, and iv) the fairness of service to different bandwidths. In general, regarding the circuit blocking probability, our algorithm achieved the best performance working with First-Fit (FF). Our algorithm using the FF has a minimum gain of 78.10% and 55.75% compared to the KS-PC-FF and MD-PC-FF algorithms, respectively, when the network attends 7 different values of bandwidth. Regarding the bandwidth blocking probability, the proposed algorithm using the FF has a minimum gain of 71.96% and 41.89% compared to the KS-PC-FF and MD-PC-FF algorithms, respectively. In general, regarding fairness, the proposed algorithm exhibits superior performance compared to the KS-PC and MD-PC algorithms.