Towards Minimum Inter-Controller Delay Time in Software Defined Networking

The fundamental idea behind Software Defined Networking (SDN) architectures is to decouple the control plane and data plane of the network to simplify the complexity of the network and centralize the control plane. A major feature of an SDN is the ability to have the controllers distributed over the network to solve the problem of a single point of failure at the controller, and to increase scalability and flexibility. Despite the flexibility and scalability of using multiple controllers, which facilitates the use of a larger number of network switches, yet the intercommunication cost between distributed controllers is still a key challenge in SDN. This paper presents an effective approach for the controller placement problem in software defined networks that aim to minimize the communication delay time between the controllers and the delay time between controller and switch. The major concept employed in this work is the Connected Dominating Set (CDS). Furthermore, an algorithm using the Minimum Connected Dominating Set (MCDS) is presented in which the delay time between the distributed SDN controllers is minimized. Simulation results are presented to show the efficiency of our approach compared to previous methods.