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

这项提议将为Web和其他按需数据交付系统开发下一代数据交付技术，这些系统包含大型、流行、广泛共享的数据文件。该项目包括几项研究工作。一个关键目标是设计改进的(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易于处理的模型来计算区域缓存内容，以最大限度地减少具有不同对象长度和传输速率以及具有不同区域服务器功能和客户端负载的系统的传输成本。第三个目标是通过使用优化的缓存内容计算来确定关键系统和工作负载参数对交付成本和最佳缓存策略的影响，从而得出基本的系统设计原则。第四个目标是开发对动态调度传递体系结构的扩展，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施问题，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、以及协调(远程)信息源服务器和区域/代理服务器之间共享数据交付的方法。这项研究的结果正在纳入一个按需提供数据的原型系统中，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.