On-Demand Delivery of Large Popular (Multimedia) Data Files

该提案将为Web和其他包含大型、流行的、广泛共享的数据文件的按需数据传递系统开发下一代数据传递技术。该项目包括几项研究工作。一个关键目标是设计改进（或优化）的交付体系结构，以减少（或最小）服务器带宽提供即时服务。另一个关键目标是开发可处理的模型来计算具有不同对象长度和交付速率的系统的区域缓存内容，从而最小化交付成本，并且具有异构的区域服务器功能和客户端负载。第三个目标是通过使用优化的缓存内容计算来确定交付成本和最优缓存策略如何受到关键系统和工作负载参数的影响，从而得出基本的系统设计原则。第四个目标是开发动态调度交付架构的扩展，以优化对（编码的）可变比特率数据流的支持。最后，该项目将解决几个实现问题，包括动态调度数据段的服务器磁盘布局，通知客户调度和重新分配的多播段交付的方法，以及在（远程）信息源服务器和区域/代理服务器之间协调共享数据交付的方法。这项研究的结果正在纳入一个按需数据交付系统的原型，以证明实施的可行性，并验证预期的性能改进。

This proposal will develop next generation data delivery techniques for the Web and other on-demand data delivery systems that contain large, popular, widely shared data files. The project includes several research efforts. One key goal is to design improved (or optimized) delivery architectures that provide immediate service at reduced (or minimal) server bandwidth. Another key goal is to develop tractable models to compute the regional cache contents that minimize delivery cost for systems with diverse object lengths and delivery rates, and with heterogeneous regional server capabilities and client loads. A third goal is to derive basic system design principles by using the optimized cache content calculations to determine how delivery cost and the optimal caching strategy are influenced by key system and workload parameters. A fourth goal is to develop extensions to the dynamically scheduled delivery architecture to optimize support of (encoded) variable bit rate data streams. Finally the project will address several implementation issues, including server disk layout for the dynamically scheduled data segments, methods for informing clients of scheduled and reassigned multicast segment deliveries, and methods for coordinating shared data delivery between the (remote) information source server and the regional/proxy server. The results of this research are being incorporated in a prototype on-demand data delivery system to demonstrate implementation feasibility and to validate the projected performance improvements.