Experimental demonstration of an intelligent control plane with proactive spectrum defragmentation in SD-EONs

The cooperation of software-defined networking and flexible grid optical transport technology allows operators to elastically control the network using software running on a network operating system within a centralized way. However, existing approaches dealing with spectrum fragmentation are mostly the reactive strategy, which reconfigures network resources to overcome spectrum fragmentation when the controller detects the fragmentation. In this paper, we focus on how to improve the control plane intelligence of software-defined elastic optical networks (SD-EONs) by using a proactive strategy. More specifically, we design a novel routing, modulation level and spectrum allocation algorithm (RMLSA) based on spectral efficiency and connectivity (SEC) i.e., SEC-RMLSA, in order to improve the utilization efficiency of network resources. Meanwhile, we develop a routing application and an extended OpenFlow protocol to achieve a seamless operation between the controller and the optical data plane. Moreover, all the proposed methodologies are implemented and demonstrated in an SD-EON testbed that has both OpenFlow-based control plane and data plane. Finally, the proposed framework, experimental demonstration, and numerical evaluation are reported for different optical flows. The results show the system's overall feasibility and efficiency.