Research On Proxy Caching Technology For Streaming Media Transmission

With the development of the Internet and the multimedia technology, the application of streaming media is gaining more and more popularity. However, since the current Internet is not built for real-time data transition, support is lacking in the Internet to meet delay, jitter and packet loss requirements for real-time traffic. The deficiency of such features as real time, high speed and broad band affects the media quality perceived by the end users. Furthermore, the high demands of the streaming media transition on the system I/O and network bandwidth make the server and the bandwidth bottleneck the system.While such problems can be effectively settled by the proxy caching technology, which is used to store parts or all of the data of the hot programs so as to offer service to the nearby users via a proxy caching system between the server and the users. The technology can reduce network and server load, decrease the client start-up latency, and improve the service quality. Thus, it is of great significance to study the proxy caching technology in order to boost the application of streaming media.This dissertation discusses the basic issues about streaming media, such as the basic principles, the approaches and protocols of streaming media transmission. It investigates the cache replacement algorithm and scheduling algorithm and proposes a new efficient caching policy. In addition, it also designs and implements a prototype of proxy caching system whose effectiveness is also tested and validated. Specifically, the main work done in this dissertation is as follows:①It does a profound research on the efficient caching policy. According to segmentation-based caching, the present study proposes the cache replacement algorithms for streaming media based on smallest cache utility. Moreover, it also puts forward the patching algorithm with dynamic cache on the basis of a survey of the current scheduling techniques.②Based on the caching policy proposed previously, the present study also designs and implements a prototype of proxy caching system, in which, with the direct storage of RTP packs, the caching and transmission of media data are irrelevant to the media format. Meanwhile, some crucial implementing issues are analyzed in detail.③It validates the effectiveness of the system through performance results from prototype implementation. As expected, the system can realize the caching task and have better performance on improving the byte hit rate, decreasing the average start-up latency and reducing the occupation in transitional channel. Therefore, the caching policy proposed in the study is proved to be effective and applicable.