Improving performance of TCP for wireless network using SDN

This paper addresses the problem of non-optimal performance of Transmission Control Protocol (TCP) over Wi-Fi networks. TCP considers packet loss as a signal for congestion leading to reduced sending rate. This idea works well for the wired networks where majority of the packet losses are due to congestion. However, in wireless networks, packets are mostly lost because of transmission errors and mobility of the end hosts. Also, when packets are lost due to disassociation of the receiver from the network during mobility, sender remains idle for a significant period even after the receiver is re-associated. In this paper, we present the design and implementation of Software Defined Network (SDN) assisted TCP for wireless networks. In our approach, mobility induced packet losses are tackled smartly to avoid reduction in sending rate. Further, the data transfer starts immediately as soon as the receiver is re-associated to the network during mobility. Unlike existing solutions, our SDN assisted TCP does not violate the end-to-end semantics and no modification is required in the TCP protocol running at the end hosts. We have implemented and evaluated our approach using Mininet Wi-fi emulation platform. The results establish the applicability of our approach.