一种分布式VOD 系统的服务策略

采用一种新的分布式VOD(Video-on-demand)系统结构来进行大规模视频点播服务, 有效地解决了制约VOD 系统应用的资源瓶颈问题。分析了这种体系结构下的服务模型, 并提出了一种新的服务策略。这种服务策略通过减小服务延迟和提高系统效率来大大增强系统服务能力。根据服务队列的优先级, 顺序地建立主流, 并且在大规模视频服务中只需少量的主流。实际结果表明, BatchPatch 流调度策略由于考虑系统的共享度和用户平均等待时间而比其它算法效率更高。对大规模VOD 系统而言, 这个服务策略是一个效率高且性价比好的策略。

A Servicing Policy of Distributed Video-on-Demand System

A novel architecture of a distributed VOD system is introduced to perform large scale VOD service, solving the "neck-bottled" problem in VOD system. Servicing model is analyzed based on that architecture,and a novel serv icing policy is proposed. It includes admitted control and stream schedule calle d BatchPatch. It can largely increase system service ability by eliminating the average service latency and improving the system effeciency. Multicast streams are created orderly according to service queue priority value and fewer multicas t streams are needed for the large scalable video-on-demand service. The real results show that BatchPatch schedule is more effictive than others, with respec t to both system resource shared with others and average user waiting time (serv ice latency)for a fixed available resource. In conclusion,the servicing policy i s an efficient and economical policy for large scale VOD system.