Software Defined Networking (SDN) has emerged as a new technology that enabled dynamic adaptation and configuration to the traditional networking. In this work, using SDN centralized control, we propose a path algorithm to avoid congestion in data communication networks. Our proposed algorithm will find a path between the source and the destination nodes by considering hop counts and the available bandwidth among the links. The path we find can be slightly longer, but is less congested compared to the congested least hops path. The found path will lead to better traffic load distribution in the network. We implemented the proposed algorithm and carried out experiments in Mininet using RYU controller. Our algorithm shows a good performance improvement in resolving the congestion when compared to the existing path algorithm in the RYU controller.

Opportunistic networking is a new communication paradigm which explores the potential of inter-device contacts due to human mobility [3, 5]. Intermittent connectivity, non existence of an end-to-end path between nodes and extreme dynamism in topological structure are inherent characteristics of opportunistic networking [2, 5]. In opportunistic networking devices make control and management decisions by themselves with locally available information. The unique differences that draw the line between opportunistic networking and other legacy networking environments call for newer approaches for systems development.