A Resource-Adaptive Transcoding Proxy Caching Strategy

With the emergence of pervasive computing, the Internet client devices have become highly heterogeneous. Transcoding proxies are used to adapt media streams to suit diverse client devices. In a transcoding proxy based streaming system, CPU and network are both potential bottleneck resources. In this paper, a resource-adaptive transcoding proxy caching mechanism is proposed, which deals with network and CPU demand in an integrated fashion and aims to improve the system’s potential service capability. First, we explore the network gain and CPU gain of caching multiple versions at the same time. By introducing a time-varying influence factor α(t), the aggregated resource gain of the caching system is derived. Then, we derive the merit function of caching a single object under a given caching status, and design a cache replacement algorithm called RAC. Simulation shows that, on the primary metric of request blocking ratio, RAC outperforms LRU and LFU markedly.