Demonstration of Multi-Domain Spectrum Defragmentation With Minimum Controller-Participation Degree in Elastic Optical Networks

Abstract

Spectrum fragmentation is a critical issue in elastic optical networks, which leads to inefficient spectrum utilization and high blocking probability. Spectrum defragmentation is considered to conduct reconfiguration of the deployed lightpaths according to different optimization strategies. Compared with the single-domain scenario, spectrum defragmentation in the multi-domain becomes much more complex and challenging due to the necessity of multi-domain cooperation. Based on the hierarchical control architecture of software-defined networking (SDN), this paper proposes a multi-domain defragmentation (MD-DF) scheme with minimum controller-participation degree (CPD). The concept of CPD is introduced to quantize the times that local controllers are involved in multi-domain defragmentation. Based on whether the potential blocked lightpath goes through inter-domain links, the MD-DF scheme includes intra-domain DF and inter-domain DF. The proposed scheme is implemented in the SDN control plane, and experimental results validate its overall feasibility. Meanwhile, the performance of the proposed scheme is evaluated in simulation with three different ratios of intradomain lightpaths. Simulation results indicate that the MD-DF scheme can optimize the utilization of the spectrum resource and achieve a better blocking probability. In addition, this paper also compares intra-domain DF with interdomain DF in terms of operation latency and execution times.