Cache Research And Implementation Of Streaming Media Proxy

In recent years, with the increasing popularity of multimedia on demand applications, multimedia content transmission takes up most of the current Internet traffic, leading to the backbone bandwidth tension and longer user access latency. The Proxy Cache not only provides NAT functions, but also is an effective solution to resolve that contradiction. That is, a proxy server is deployed around users in order to alleviate server load, reduce network bandwidth and network traffic, and shorten the network delay by caching hot multimedia objects and serving follow-up media requests. In this way, the quality of server is mostly improved.Cache replacement algorithm and scheduling algorithm are studied according to the main factors of affecting the performance of streaming media caching and transmission resource consumption, whose main research strategy is proxy cache, and then is the design of streaming media proxy cache system.We use the strategy of one unicast form server to proxy and multiple unicast from proxy to clients, it just like the multicast from server to clients. This strategy is called application-level multicast. It can be realized easily and low requests on clients, but this method consumes very large network resources form proxy to clients, so it could be used around the clients, and the campus lab environment meets this requirement.The work and contribution of this paper is as follows:(1) Study and analyze Streaming media caching strategies and distribution technology, finally select the mixed strategy of the prefix cache and variant-length based segment cache, which is based on dynamic scheduling after comparing their advantages and disadvantages. It improves the cache performance greatly.(2) According that the current cache replacement algorithms have the problem of inaccurate evaluation of the caching utility because their standards are the accessing time and frequency of the media, the paper proposes a network self-adaptive cache replacement algorithm to prefix part and a cache replacement algorithm with future prediction to suffix part.(3) Study and realize the streaming media related protocols, and design a new kind of streaming media proxy server based on the mixed strategy of the prefix cache and variant-length based segment cache, with the direct storage of RTP packets. Then the proxy doesn't need consider the media format, so its functions are enhanced.At end of the paper, the performance of the new kind of streaming media proxy and compare is tested comparing with the original prefix cache and segment cache based on sub-index technology. And we conclude that the new kind of proxy is deployed in the edge of network, and using the proxy a good effect is made in reducing network traffic, transmission delay and load of streaming media server.