Network cost optimization-based capacitated controller deployment for SDN

As a novel network paradigm, software-defined networking (SDN) is capable of simplifying network management and offering flexible support to various user services. In order to meet the rapidly increasing transmission demands of SDN switches, the controller deployment strategy in an SDN scenario should be designed. In this paper, we investigate the capacitated controller deployment problem for SDN. Consider the signaling transmission and processing performance of switches and address the worst-case performance, we define network response time (NRT) as the maximum control plane response time of switches. Then aiming to achieve the tradeoff between NRT and the cost of controllers, we introduce the concept of network cost which is defined as the weighted sum of NRT and controller cost. The capacitated controller deployment problem is formulated as a constrained network cost minimization problem. To solve the optimization problem, we propose a two-stage heuristic algorithm, which first tackles the controller deployment subproblem under the unlimited capacity constraint, and then solves controller-type matching subproblem. Specifically, during the first stage, a minimum eccentricity-based controller deployment algorithm is designed to determine the number and location of controllers as well as the association strategy between controllers and switches. During the second stage, a greedy method-based controller-type matching strategy is proposed to determine the types of deployed controllers. Extensive simulations are performed and the results certify the effectiveness of the proposed algorithm.