On Design and Performance Evaluation of Multimedia Proxy Caching Mechanisms for Heterogeneous Networks

Multimedia Proxy caching (MPC) can improve scalability by reducing network load, and maximize delivered quality to heterogenous clients. The notion of delivered quality is a new dimension in design and evaluation of MPC mechanisms that does not exist in traditional web caching. Furthermore, there is a fundamental tradeoff between delivered quality, network load and delay. Previous studies on MPC did not consider delivered quality in design and evaluation of MPC mechanisms. This paper makes three contributions: First, we explore the design space of MPC mechanisms with respect to this tradeoff. We identify three promising caching strategies that are either conservative(LQC) or aggressive(HQC), or adaptive(AQC) with respect to delivered quality, by leveraging this tradeoff differently. Second, we present the first methodology for comprehensive evaluations of MPC mechanisms with respect to this tradeoff. Third, we use our proposed methodology to conduct simulation-based comparison among the three strategies. Our simulation results show that HQC can always maximize delivered quality at the cost of high network load and long delay. In contrast, AQC, can deliver moderate to high quality at the substantially lower load and no delay. Delivered quality, network load and delay are always low in LQC.