부산대학교 도서관

This electronic Because of the limited capacity of a single controller, multiple controllers need to be deployed in a large software defined-network. The assignment of controllers and switches is a significant problem that may affect the flow setup time. Since the network traffic is dynamic, static controller assignment may lead to high flow setup time. To reduce the flow setup time and improve the performance of networks, we focus on the dynamic controller assignment problem in this paper. We propose a controller assignment scheme for multiple controllers. It adjusts the assignment among controllers and switches dynamically based on the load of switches and the capacity of controllers. We model each controller as an M/PH/1 queue and use a heuristic called LANS to optimize the controller assignment based on the model. We compare our method with DCP-SA in two cases. The results show that LANS can balance the load of controllers better than DCP-SA. The flow setup time under LANS is 8% and 17% lower than DCP-SA and LANS makes 0.8 and 1 fewer migrations on average than DCP-SA in the two cases.