Network design for rate adaptive media streams

Rate adaptive multimedia streams offer significant system and client benefits over nonadaptive streams. These benefits come at the price of increased complexity in providing adequate network support and difficulty in understanding how rate adaptation protocols affect client perceived QoS. In this paper we define quality of service in terms of the mean rate seen by the client. We identify an intuitive optimal adaptation policy that maximizes QoS. We suggest an appropriate scaling regime for rate adaptive streams and identify asymptotic QoS for large capacity networks under the optimal adaptation policy. Implementation of the optimal adaptation policy presents several obstacles that render it infeasible. We define a multiclass admission control policy that achieves asymptotically equivalent QoS to that achieved under the optimal adaptation policy, but without the need for dynamic adaptation. Our work carries implications for network designers and content providers.