FlexStream

Abstract

We present FlexStream, a programmable framework realized by implementing Software-Defined Networking (SDN) functionality on end devices. FlexStream exploits the benefits of both centralized and distributed components to achieve dynamic management of end devices, as required and in accordance with specified policies. We evaluate FlexStream on one example use case -- the adaptive video streaming, where bandwidth control is employed to drive selection of video bitrates, improve stability and increase robustness against background traffic. When applied to competing streaming clients, FlexStream reduces bitrate switching by 81%, stall duration by 92%, and startup delay by 44%, while improving fairness among players. In addition, we report the first implementation of SDN-based control in Android devices running in real Wi-Fi and live cellular networks.