Internet上的流媒体特性及用户访问行为研究

通过跟踪CERNET中典型流媒体服务器日志,分析了流媒体特性和用户访问行为,为在Internet上通过内容分送网络(CDN)高效分送流媒体内容及流代理服务器的仿真与设计提供实验依据.结果表明:流对象大小和播放持续时间较好地符合对数正态分布,平均位速率呈"双峰"变化特性;对流媒体的访问呈现出比Zipf分布更强烈的偏向性;请求具有定域性,其是由对文件排列中的前若干文件的频繁访问所造成,这些请求间具有较强时间相关性.指出了上述结论对仿真、设计和实现流媒体缓存代理服务器的意义.

Study on characterizing streaming media and user access to media on the Internet

Through tracing the log data of four typical streaming servers of CERNET, the characteristics of streaming media and its access pattern to attempt to give evidence of the key component design or simulation in streaming system such as streaming proxy in CDN were analyzed. The results show that the size and playback duration of media files fit the lognormal distribution well but the average bit rate varies in a "bi-peak" model; references to streaming media present stronger skew popularity than Zipf distribution; temporal locality of the reference is unclosed. Both the locality and temporal correlation that exists in the request stream are enclosed that it is the hot references to the few front media files of the file rank that cause the locality, while these requests present stronger temporal correlation. Implications of above conclusions in analyzing, designing and implementing the streaming cache proxy are elucidated.