多控制器集群流媒体缓存代理的研究

为满足用户分散的大规模视频流媒体应用需求，该文提出了一种基于多控制器集群缓存代理结构(Multi- controller based Cluster Streaming Cache Proxy, MCSCP)，该体系由一组控制器构成控制子系统，由多个内容存储器构成分布式存储子系统。对控制子系统的关键问题进行了深入研究：采用图论思想给出控制器组的选取算法，设计了一种基于优先级的主控制器选举和在线切换协议(Priority based Master-controller Election and Handover, PMEH)。建立数学模型分析了多控制器体系对系统可靠性的改善程度，讨论了控制器选取算法的性能，研究了协议中报文发送间隔变量与系统开销的关系，并使用仿真实验给出了该参数的最佳取值范围。

Research on Multi-controller Based Cluster Streaming Cache Proxy

To satisfy the requirement of large-scale streaming application with dispersive users, a novel system architecture of Multi-controller based Cluster Streaming Cache Proxy (MCSCP) is proposed. Two subsystems are introduced in this architecture: a control subsystem consists of multiple candidate cooperative controllers, and a storage subsystem is composed of content storage group. Key techniques in the control subsystem are discussed deeply: based on the graph theory, an algorithm for the selection of candidate controllers is presented; a protocol of Priority based Master controller Election and Handover (PMEH) is designed. The mathematical models are achieved to analyze the improvement in system reliability by using cooperative controllers architecture, to discuss the performance of controller election algorithm and to evaluate the relationship between the system cost and the variable of message interval. Simulation experiment is also carried out to obtain the optimal range for the value of this variable.