Routing and Spectrum Assignment for Software-Defined Elastic Optical Networks

Software-defined Elastic Optical Networks (SD-EONs) combine software-defined network (SDN) with elastic optical networks (EONs) to further improve the spectrum utilization of routing and spectrum assignment (RSA) algorithms. However, some existing RSA algorithms usually only consider the hops when solving route subproblem, whereas the link spectrum status is also very important. At the same time, they usually neglect the vertical fragmentation between neighbor links during the spectrum assignment. Therefore, we propose an innovative hop and consecutiveness-based routing and fragmentation-aware spectrum assignment (HCR-FSA) algorithm with a joint consideration of hops and spectrum consecutiveness in routing selection and pays attention to both horizontal and vertical fragmentations during spectrum assignment. We implement our HCR-RSA algorithm in RYU controller to evaluate its performance. The experimental results show that our algorithm achieves better blocking probability and fragment degree compared with the previous works.