Control plane delay minimization based SDN controller placement scheme

Software defined networking (SDN) has been proposed as a novel centralized architecture which is capable of offering flexible network management and user quality-of-service (QoS) guaranteed applications. The problem of controller placement in SDN, i.e., determining the locations of the controllers has received considerable attention in recent years. In this paper, we jointly consider the control plane delay between switches and controllers and between controllers and formulate the controller placement problem as a control plane delay minimization problem subject to switches and controllers association constraints. As the optimization problem formulated is an NP-hard problem, which cannot be solved easily, we propose a heuristic method based on the K-means algorithm and the Dijkstra algorithm. Numerical results demonstrate that the proposed algorithm offers better performance than previously proposed algorithm.