CAREER: A Receiver-Driven Framework for Scalable and Adaptive Peer-to-Peer Streaming

覆盖网络上的流传输的现有解决方案采用应用级多播的思想，其中参与的对等体形成拓扑感知的树结构以最小化总体延迟。由于树结构的固有带宽限制，这些方法无法最大化向各个对等体递送的流的质量。本计画设计、开发并评估一个接收端驱动架构，以建构点对点网路中串流的频宽感知覆盖，称为帕尔斯。帕尔斯与常见的基于树的覆盖构造方法不同，允许每个对等体独立地和自私地确定连接到覆盖的最佳方式，以最大化其自身的交付质量。类似于一组竞争的TCP流，覆盖层中独立且自私的竞争对等体达到“均衡”，其中不仅将传递给每个对等体的带宽最大化到其可用带宽的公平份额，而且所得到的非结构化覆盖层是全局有效的。这个项目调查了三个广泛的领域：（一）从多个拥塞控制流的自适应流技术，（二）可扩展的资源发现和自适应资源选择的技术，和（三）分布式多媒体缓存方案的无缝支持异步对等体。此外，该项目还提供了帕尔斯框架的原型实现，作为一个开源模块化中间件，将公开提供。该原型使研究人员能够进行互联网范围的实验，并调查帕尔斯和各种编码方案之间的相互作用。该原型还可以作为课堂上的教育工具，为学生带来P2P流媒体技术的实践经验。

Existing solutions for streaming on overlay networks adopt the idea of application level multicast, where participating peers form a topologically aware tree structure to minimize overall delay. These approaches are unable to maximize quality of delivered stream to individual peers because of the inherent bandwidth limitation of the tree structure. This project designs, develops and evaluates a receiver-driven framework to construct "bandwidth-aware" overlays for streaming in Peer-to-Peer (P2P) networks, called PALS. PALS departs from the common tree-based approach to overlay construction and allows each peer to independently and selfishly determine the best way to connect to the overlay in order to maximize its own delivered quality. Similar to a group of competing TCP flows, independent and selfishly competing peers in an overlay reach an ``equilibrium'' in which not only delivered bandwidth to each peer is maximized to its fair share of available bandwidth, but also the resulting unstructured overlay is globally efficient. This project investigates three broad areas: (i) techniques for adaptive streaming from multiple congestion controlled senders, (ii) techniques for scalable resource discovery and adaptive resource selection, and (iii) distributed multimedia caching schemes for seamless support of asynchronous peers. Furthermore, this project delivers a prototyped implementation of PALS framework as an open-source modular middleware that will be made publicly available. The prototype enables researchers to conduct Internet-wide experiments and investigate interactions between PALS and various encoding schemes. The prototype also serves as an educational tool in the classroom to bring hands-on experience with P2P streaming technology to students.