Buffer control at video-streaming proxy

Proxy servers can be used to stream video stored at a geographically separate location. This separation between the proxy server and the storage introduces a non-negligible delay in retrieving video frames in real time. We develop an effective scheme to achieve consistent, high streaming quality under such delays. Central to the scheme is the control of buffer occupancy at the proxy server. We model the buffer as a bilinear dynamical system disturbed by a point process with stochastic state-dependent intensity, reflecting the behavior of an additive-increase/multiplicative-decrease transport protocol. Using the buffer model, we construct two controllers based on prediction of future system states, taking into account both the delay and the state-dependent disturbance. Our empirical study illustrates the effectiveness of the scheme and shows that the controllers exploiting the buffer model perform well in overcoming the adverse impact of the retrieval delay.