一种基于周期合并策略的流调度算法  

A Stream Scheduling Algorithm Based on Period-Patching Strategy

作　　者：向哲[1] 钟玉琢[1] 冼伟铨[1] 

机构地区：[1]清华大学计算机科学与技术系,北京100084

出　　处：《软件学报》2001年第8期1181-1189,共9页Journal of Software

基　　金：国家自然科学基金资助项目 (6 99730 2 5 );国家重点基础研究发展规划 973资助项目 (G19990 32 70 0 )&&

摘　　要：在视频点播系统中 .流调度算法通过降低服务延迟和提高服务效率等措施 ,可显著提高系统服务能力 .提出了一种新的流调度算法—— Period Patch.该算法在 Patching算法的基础上引入了周期调度的规则 .Period Patch算法可以通过少数有序生成的组播节目流提供大量 TVOD(true video-on-demand)级服务 .Period Patch算法还保证系统在资源耗尽的情况下 ,可以提供高效、可预测的 NVOD(near video-on-demand)级服务 .仿真结果表明 ,Period Patch算法在 TVOD服务下的系统资源消耗程度和在有限资源下的平均用户等待时间均优于其他算法 .总之 ,Period Patch是一种高效。Stream scheduling algorithm used in video -on -demand (VOD) system can largely increase system service ability by eliminating the service latency and improving the system efficiency. In this paper, a novel stream schedule called PeriodPatch is proposed. On the basis of Patching, a PERIOD rule is introduced, so that multicast streams are created orderly and fewer multicast streams are needed for the true video -on -demand (TVOD) service. Furthermore, PeriodPatch schedule ensures that the system can provide near video -on -demand (NVOD) service with a predictive and acceptable latency to the client if resource are exhausted out. The simulation results show that PeriodPatch is more efficient than others, with respect to both system resource required for TVOD service and average client waiting time (service latency) for a fixed available resource. In conclusion, the PeriodPatch is an efficient and economical stream schedule for VOD system.

关 键 词：网络多媒体 周期合并 流调度算法 视频点播系统 

分 类 号：TN948.64[电子电信—信号与信息处理]