Partitioned Controller Placement in SDWANs for Reliability Maximization with Latency Constraints

The separation of the control plane from the data plane has made the novel paradigm, Software-Defined Networking (SDN), available in both small-scale and large-scale networks. Unlike small-scale networks with merely one controller for deployment, employing multiple controllers is essential to meet the requirements of reliability and scalability in Software- Defined WANs (SDWANs). However, the occurrence of the node or link failures in the control plane may severely deteriorate the system performance. Therefore, how to determine the number and locations of the distributed controllers in SDWANs for enhancing network reliability with propagation latency constraints worth in-depth study. In this paper, we formulate the controller placement problem in SDWANs mathematically and propose a heuristic algorithm with low computational complexity to address it. By incorporating the centroid-based network partition scheme, we further ameliorate the CPP for maximizing reliability with latency constraints. Experiments are performed on real network topologies to validate the effectiveness of our approach for controller placement problem in SDWANs.