Dynamic multi-hop switch handoffs in Software Defined Wireless Mesh Networks

Software Defined Networking (SDN) allows network administrators to customize the network according to the requirements. The centralized control plane in SDN finds its application in several areas of networking, especially in Wireless Mesh Networks (WMNs). In this paper we propose two dynamic switch handoff schemes for Software Defined Wireless Mesh Networks (SDWMNs) with multiple controller architectures. We use the metrics end-to-end Round-Trip-Time (RTT) and multi-hop Expected Transmission Count (ETX) for computing the handoff decision. Two schemes are analyzed by deploying a testbed consisting of mobile routers and multiple controllers. Our results show that ETX is a better metric for switch handoffs compared to RTT in mobile environments. Further, we propose an anticipatory handoff algorithm, based on multi-hop ETX, which predicts the near future of network behavior and makes the handoff decision prior to actual handoff. Finally, we observe significant performance improvement with our ETX-based handoff scheme as compared to architectures with a single controller.