基于混合模式的流媒体缓存调度算法  

Dynamic Scheduling Algorithms for Streaming Media Based on Hybrid Content Delivery Network

作　　者：叶剑虹[1,2] 叶双[1,3] 

机构地区：[1]华侨大学计算机科学与技术学院,厦门361021 [2]西安电子科技大学机电工程学院,西安710126 [3]南京理工大学计算机科学与技术学院,南京210094

出　　处：《计算机科学》2013年第2期61-64,83,共5页Computer Science

基　　金：厦门市科技局科技计划创新项目(3502Z20103027);华侨大学科研启动基金项目(09BS514);中央高校基本科研业务费专项资金项目(JB-ZR1130);华侨大学科研基金项目(11HZR05)资助

摘　　要：介绍了一种结合了CDN和P2P互补优势的流媒体混合内容分发网络(HyCDN)。针对HyCDN不同区域提出了相应的缓存算法,域内用户端综合考虑了流媒体前缀字节的有用性、文件的传输代价及点播热度,在此基础上提出缓存替换算法(Comprehensive Value Cache Replacement Algorithm for P2P,CVCR4P2P);对域间边缘服务器采用补丁预取与调度算法(Dynamic Scheduling Algorithm for Proxy Caching,DSA4ProxyC),通过基于用户访问情况自适应伸缩缓存的分配方案,使流媒体后缀部分在边缘服务器中缓存的数据段与其流行度成正比。理论分析及实验结果表明,混合流媒体缓存调度策略的实施能有效地降低骨干网络带宽资源消耗,对用户请求到达速率的变化具有良好的适应性。A hybrid content delivery network combining complementary advantages of CDN and P2P called HyCDN for streaming media was presented. The CVCR4P2P （Comprehensive Value Cache Replacement Algorithm for P2P） algo- rithm was proposed for the peers inside domain, which considers bytes benefit of prefix data, transmission cost and ac- cess rate of streaming media. Another algorithm, DSA4ProxyC （Dynamic Scheduling Algorithm for Proxy Caching）, which joints the proxy caching and server scheduling strategies for proxies between domain was also shown. It employs the scheme of cache allocation based on the current hatching interval that has non-zero requests, which can be updated periodically according to the popularity of streaming media object. The principle is obeyed that the data cached for each streaming media object are in proportion to their popularity at the proxy server. Theoretical analysis and simulation re- suits show that the hybrid dynamic scheduling can effectively reduce server and network bandwidth usage, and also has a very good adaptability for the variety of the request arrival rate.

关 键 词：流媒体 补丁预取 缓存替换 调度算法 

分 类 号：TP368.5[自动化与计算机技术—计算机系统结构]