【作者】 徐广；

【导师】 唐瑞春；

【作者基本信息】 中国海洋大学 ， 计算机软件与理论， 2011， 硕士

【摘要】 随着Internet的快速发展和个人计算机性能的提高,人们不再仅仅满足传统的文字网页浏览、邮件收发、在线聊天等应用。由于流媒体特有的娱乐性和交互性,它越来越受到人们的青睐,并且成为目前因特网应用的最快增长点。本文通过对CDN和P2P优缺点及目前CDN与P2P主流融合方式的研究,提出了基于CDN与P2P的混合网络架构HCPMSA (Hybrid CDN-P2P Streaming Media Service Architecture),另外对影响系统稳定性和工作效率的关键技术进行了研究。本文的具体研究内容和研究工作如下:(1)研究了CDN与P2P技术各自的优缺点,及现在的研究的两种技术的主要融合方式。设计了一种即可靠又易管理同时又具有可扩展性的基于CDN和P2P混合网络架构的体系结构。(2)研究了影响系统稳定性的主要因素,通过对各个因素的分析本文建立了系统稳定性的数学模型,通过系统稳定值把系统分为三个等级的稳定状态。(3)研究了目前流行的P2P节点选择算法,建立了可靠度的数学模型;提出了一种基于可靠度的P2P资源节点选择算法,此算法综合考虑了服务节点的可靠度、负载均衡及贡献度的问题。(4)研究了流媒体编码扩展技术,系统把流媒体文件分为不同的等级。把用户请求分为不同的优先权,提出了一种基于系统稳定性的分级预防与恢复策略。该策略中的分级指的是媒体文件分级、用户优先权的分级及系统稳定性的分级。本文的实验基于Cygewin+NS2环境,测试了系统的吞吐量、系统中节点的抖动率及请求成功率,结果显示这几方面都有明显的提高。说明本文设计的方案能够在保证一定程度服务质量的的同时提高系统的稳定性。本文的创新点如下:(1)设计一个利用了CDN的可靠性、可管理性和P2P技术的可扩展性的CDN与P2P技术的网络架构。(2)根据系统的负载状况和网络状况提出了系统稳定值的概念,设计一个基于系统稳定值的分级预防与恢复调度策略,设计了一个基于可靠度的P2P节点选择算法此算法综合考虑了节点负载均衡、节点贡献度、节点可靠度的问题。更多还原

【Abstract】 With the rapid development of Internet and PC performance improvement,people no longer just satisfied with traditional text web browsing, email transceiver and online chatting application. Because of the peculiar entertainment and interactivity of streaming media, it has more and more get the favor of people, and become the fastest growth in the current Internet application.In this paper, based on the research of advantages of CDN and P2P and current mainstream fusion way, we proposed the mixed network architecture with CDN and P2P HCPMSA (Hybrid CDN-P2P Streaming Media Service Architecture), in addition, the key technology which effect stability of the system and the efficiency is discussed.The special research content and work are as follows:(1) We have made comprehensive research on the advantages, disadvantages of CDN and P2P, and the main fusion way of the two technologies now. A reliable, easily managed and extensible mixed network architecture with CDN and P2P.(2) We study the main factors influencing system stability. The mathematical model of analysis of the factors is established in this paper, which sets the system to a 3 hierarchy through the stable value.(3) The popular P2P node selection algorithm is investigated in this article, and a mathematical model of reliability is established; a P2P resource node selection algorithm, based on the reliability, comprehensively considering the reliability, load balance and contribution of service node, is put forward.(4) We research streaming media coding expand technologies. In the system, streaming media files are divided into different grades, and the user requests are divided into different priorities. A strategy based on the stability of the system classification prevention and rehabilitation is proposed. The grading in the system refers to the media file classification, users of priority and the stability of the system hierarchical classification. The experiment environment is based on Cygewin+NS2. It mainly tests the system throughput, jitter rate and request rate of the peers. The experiment result shows great improvement in these parameters. This proves that the design of this system can guarantee the QoS as well as improve the stability of the system.The innovation points of this paper are as follows:(1) It gives a network architecture of CDN and P2P which combines the reliability and manageability of CDN and the extendibility of P2P.(2) According to the load situation and network condition, it puts the concept of system stability value and designs a prevention and scheduling strategy based on it.It designs a peer choice algorithm based on reliability. The algorithm considers peer’s load balance, contribution value and reliability at the same time.更多还原