文档介绍：华中科技大学
硕士学位论文
一种对等网络流媒体直播算法的设计与仿真实现
姓名:程刚
申请学位级别:硕士
专业:通信与信息系统
指导教师:黄佳庆
2011-01-10
摘要
流媒体直播作为多媒体技术在互联网上的热点应用而受到广泛的研究与关注。
对等网络流媒体直播技术由于其部署成本低,良好的可扩展性等优势成为当今流媒
体直播的主流解决方案。
针对目前 P2P 流媒体直播系统所面临的问题,提出了一种基于异步数据传输和中
心目录服务的非结构化的 P2P 流媒体直播系统。针对互联网终端的网络带宽与计算
能力的异构性,采用分层编码技术,并通过采用轮转请求流媒体数据片段的方法,
使得节点能够根据自身能力和网络环境自适应的调整传输速率,达到播放连续度和
视频播放质量的最佳平衡。通过流量局域网策略,来控制跨 ISP 链路的网络流量。
另外,提出了一种基于贡献值的激励机制来保证对等网络节点之间的公平共享。
本文扩展了通用的并行分布式网络仿真平台 PDNS,在该平台上实现了该直播
协议,并详细论述了伙伴节点管理,数据传输调度,流量局域化等算法设计和实现上
的细节。最后,通过最多达上万节点的大规模的数据包级的网络仿真,分析了各种
协议参数和策略对系统性能的影响,验证了本文的方案是可行和有效的。本文提出
的直播系统具有良好的可扩展性,在增强播放质量,减少服务器带宽压力和跨 ISP
链路流量等方面都具有一定的优势,提升了用户体验的质量。仿真的数据结果具有
一定的参考价值,有利于对 P2P 流媒体直播算法的进一步研究。

关键词: 流媒体直播对等网络分层编码网络仿真
I
Abstract
Live media streaming, the most typical multimedia application in , attracts
widely interest and study. Peer-to-peer technology, which shows great advantages on
lower deployment cost and higher scalability, now became the most popular solution in
live streaming.
This thesis first discussed the ing of current P2P live streaming systems. We
then proposed an unstructured P2P live streaming media system, which based on
asynchronous data transfer and centered directory service. Towards peers’ heterogeneous
in calculation ability and access-layer bandwidth, we adopt one kind of round-robin
request strategy with layered video coding, which enables peers adaptive adjustments on
transmission rate,to achieve the optimal balance on playback continuity and video quality.
We design a traffic localization strategy to work traffic across different ISPs.
We also proposed a contribution-based incentive mechanism which ensures fair data
sharing among peers.
We implement the protocol in the Parallel/work Simulator PDNS and
discuss the protocol design and implementation details, including the partner
management, data transmission scheduling, traffic localization algorithms. Finally, large
scale packet-level simulation illustrates that