Cost-Effective Controller Placement Problem for Software Defined Multihop Wireless Networks

Abstract

In an SDN architecture, solving the controller placement problem (CPP) in a multi-controller environment plays an important role on network performance in terms of delay, reliability, control overhead, etc. In this architecture, control overhead, referred to as the network cost in this paper, consists of controller-device communications to discover the network topology, and exchange configurations and set up flow tables as well as inter-controller communications, if needed, to synchronize different network views and achieve the global view of the network. In software defined multihop wireless networking (SDMWN), because of the capacity limitation and the effect of interference on wireless links, and an in-band architecture in some types of networks to exchange both data and control traffic, it is important to solve the CPP while minimizing control overhead to reduce energy consumption, have lower packet losses and improve reliability. In this paper, the objective is to solve the CPP in SDMWN while minimizing the number of required control packets to be exchanged in the control plane. The novelty of our work is that we consider the characteristics of SDMWN and the capacity of wireless links to solve the CPP and select routes among network devices and controllers in the network. Our results demonstrate the impact of different factors such as the number of controllers, the capacity of wireless links and the arrival rate of new flows in devices on control overhead in SDMWN.KeywordsMultihop wireless networks (MWNs)Software defined multihop wireless networking (SDMWN)Controller placement problem (CPP)Control overhead