Defragmentation Using Reroutable Backup Paths in Toggled 1+1 Path Protected Elastic Optical Networks

Abstract

This work proposes a defragmentation scheme using reroutable backup paths in toggled-based quasi 1+1 path protected elastic optical networks to enhance the efficiency of defragmentation and suppress the fragmentation effect. The proposed scheme allows both reallocation of spectrum slots of backup paths and rerouting of backup paths. By using the path exchanging approach in the proposed scheme, the primary paths become the backup path while the backup path becomes the primary path. This allows to utilize the advantages of defragmentation in both primary and backup paths. Considering rerouting and path exchanging, we present to the key idea to formulate the proposed scheme as an integer linear programming (ILP) problem. A heuristic algorithm is introduced to solve the problem for large networks, when ILP is not tractable. For a dynamic traffic scenario, an approach that suppresses the fragmentation considering rerouting and path exchanging operations is presented. The numerical results indicate that the blocking probability using the proposed scheme is suppressed compared to the conventional scheme.