Traffic-aware Dynamic Controller Assignment in SDN

In this paper, we propose a dynamic controller assignment scheme while considering flow-specific requirements, with an aim to minimize controller response time in softwaredefined networks (SDN). We adopt the concept of FlowVisor, in which a virtualized platform acts as a manager between control- and data planes of SDN architecture. The proposed scheme consists of two phases – adaptive window selection and controller assignment. In the window selection phase, the virtualized manager determines time to wait before incoming flows can be assigned to controllers in adaptive manner. Based on the adaptive window size, the flows are assigned to the controllers in the second phase. We use dynamic stable-matching game to assign flows to controllers, while defining their preference lists. The extensive simulation results show that the proposed scheme is capable of minimizing controller response time by 31%, 39%, and 37% compared to the state-of-the-art schemes – simple stablematching (SM), static assignment (Static), and minimum quota processing (MQP), respectively. Further, the proposed scheme also reduces the percentage of QoS violated flows in the network by 72%, 73%, and 74% compared to SM, Static, and MQP, respectively.