The SDN controller placement problem for WAN

Large networks are always partitioned into several small networks when deploying software defined networking (SDN). The network partitioning with SDN control planes open many unanswered questions such as latency, reliability, and load balancing. This paper opens the investigation by focusing on two specific questions: given a wide-area network topology, how to partition it into several small SDN domains, and where should the controller go in each SDN domain? To answer these questions, we propose a novel approach to efficiently and accurately evaluate SDN controller placement problem for WAN. This approach uses the Spectral Clustering placement algorithm to partition a large network into several small SDN domains. After presenting our metrics of the SDN controller placement problem, we evaluate our approach using the Internet2 topology and other available WAN topologies. For testing purposes we developed a new framework to test the SDN controller in WAN. The results show its effectiveness for the SDN controller placement problem.