Delay-aware Controller Placement for Fast Response in Software-defined Network

Most of Controller placements take the Propagation Delay (PD) as the important consideration in Software-Defined Network (SDN), ignoring the influence of the Transmission Delay (TD) on the network performance. This paper provides a delay-aware controller placement for fast response. First, the Controller placement is formulated as an optimization problem based on PD and TD. Average delay and maximum delay minimization models are updated, of which the processes about the optimal solution are circumstantiated. Further, delay optimization model is deduced by fuzzy set theory. Finally, according to whether or not considering TD, two placement algorithms, Transmission and Propagation Algorithm (TPA) and Propagation Algorithm (PA), are presented. In order to measure the performance of the solutions, a factual network topology is chosen and the simulation result shows that TPA superiorities over PA in terms of response speed and network stability, the total delay of delay optimization model is less than the others.