Performance of route partitioning scheme for hitless defragmentation in elastic optical networks

The route partitioning scheme for hitless defragmentation have been introduced to increase the admissible traffic load in elastic optical networks. It facilitates the defragmentation of the spectrum through spectrum retuning. This paper further investigates the performance of the route partitioning scheme. For the heuristic algorithm, where we seek a maximum cut, we use the Goemans/Williamson relaxation algorithm, which has a 0.878 approximation factor for maximum cut. We implement the parallel retuning to speed up the retuning process, and investigate the effects of the network characteristics on the route partitioning performances. Results show that the approximation algorithm provides the optimal cut for most networks and that the route partitioning scheme with parallel retuning offers up to 9% added traffic load compared to the conventional one.