基于段流行度的移动流媒体代理服务器缓存算法

Proxy caching algorithm based on segment popularity for mobile streaming media

提出了一种基于段流行度的移动流媒体代理服务器缓存算法P2CAS2M2(proxy caching algorithm based on segment popularity for mobile streaming media),根据移动流媒体对象段的流行度,实现了代理服务器缓存的接纳和替换,使移动流媒体对象在代理服务器中缓存的数据量和其流行度成正比,并且根据客户平均访问时间动态决定该对象缓存窗口大小。仿真结果表明,对于代理服务器缓存大小的变化,P2CAS2M2比A2LS(adaptive and lazy segmentation algorithm)具有更好的适应性,在缓存空间相同的情况下,能够得到更大的被缓存流媒体对象的平均数,更小的被延迟的初始请求率,降低了启动延时,而字节命中率接近甚至超过A2LS。

A novel dynamic scheduling algorithm P^2CAS^2M^2 （proxy caching algorithm based on segment popularity for mobile streaming media） based on segment popularity for mobile streaming media was proposed. Proxy caching admission and replacement algorithm based on the object segment popularity for mobile streaming media was implemented. The principle was obeyed that the data cached for each mobile streaming media object were in proportion to their popularity at the proxy server. The cache window size was updated periodically according to the average access time of the clients. Simulation results show that this algorithm is more adaptive than A^2LS （adaptive and lazy segmentation algorithm） for the variety of the proxy server cache. It can gain more average number of Cached mobile streaming media objects and less delayed requested ratio while byte-hit ratio of P^2CAS^2M^2 is close to or exceeds A2LS under the circumstance of the same proxy cache space.