基于集群服务器的VOD设计与实现研究

提出了一个基于集群的视频点播系统，该系统能够以任意的视频翻放速率提供用户所需的服务质量，系统内服务器的配置相同，采用分布式和冗余式相结合的数据存储方案。通过预处理视频流，系统为每个视频文件的每一帧建立位图，以确定在已给定帧速率的条件下是否传送此帧。集群方案使系统具有较高的容错能力，能够提供较高的任务处理能力。而且系统能够保持负载平衡和具有可扩展能力。数据通信方式则采用了由客户端控制视频流量的RQRP协议，基于缓冲的请求-应答方案解决了重复帧的问题，保证了服务质量。

VOD System Design and Implementation Based on Server Cluster

In this paper, we proposed a clustered server scheme designed for video_on_demand system that can provide different quality of service guarantees by arbitrary_rate video playback. This design chose a symmetric architecture that consists of a set of identically configured servers, which stored data in terms of the combination of distribution and redundancy. Through the pre_processing of the video streams, we can map the data of each frame of every video into a frame map. The frame map indicates whether a frame should be sent to the client at a given frame rate. Clustered servers provided a higher level of fault tolerance and computation. In addition, the design can keep the load balanced and scalable ability. Finally,the paper discussed the buffer_based RQRP scheme that adopted the RQRP protocol to control the data flow by clients.