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题名	基于专网的P2P网络缓存拓扑建模的方法和工程实现
作者	潘海斌
学位类别	博士
答辩日期	2009-05-25
授予单位	中国科学院声学研究所
授予地点	声学研究所
关键词	点对点 内容分发 专网 机顶盒 模型 算法
其他题名	The Modeling and Engineering Realization in P2P Based on Private Network
学位专业	信号与信息处理
中文摘要	FTP/HTTP是目前Internet上内容分发的主要技术。但随着终端数目的增多，各终端下载速度会越来越慢，无法解决内容快速分发到较多终端的难题。而P2P（Peer to Peer，点对点）能够有效的将海量内容快速分发到各个终端。而且随着终端数目不断增多，下载速度会不断加快。目前已在个人业务中广泛应用，并被认为是改变Internet的四个核心技术之一。 在基于专网的P2P网络环境下的内容分发系统中，既要兼顾海量数据的快速分发，也要能将控制消息和紧急消息等能够实时的分发到各终端。 本文的研究目标是基于专网的P2P网络环境下，实现内容的快速分发，其主要内容包括如下： 针对基于专网的P2P网络特性，进行了系统建模，以便后续的系统设计、调整和验证。模型的主要特征是在网点分布较多、网点接入方式各异的情况下，能够有效准确的进行共性内容和个性内容的快速分发。 基于专网的P2P网络的内容分发系统中，任务存在着种类繁多，时效性要求不同，数量繁多，以及数据量大小无规律等特点。为了更好的进行任务调度，结合P2P的特点，本文提出了基于优先级的P2P服务调度算法。该算法借鉴了最早截止时间优先算法和蚁群算法；该算法包含任务优先级计算算法、代理服务优先级计算算法和优先级动态变更调度算法。该算法具有计算简单，对分发任务类型、数据量和任务优先级适用性强，分发效率高等特点。 而且，鉴于IP网络是尽可能服务的网络，因此为了兼容网络接入较差和接入时间较短的终端，提出了内容分发的QoS（Quality of Service，服务质量）传输机制。该机制根据分发任务的优先级、数据量大小、获得任务的终端数目等初始化数据，实时根据下载速度和任务发布的时间差动态更新下载策略，自适应下载方式，从而保证内容的快速分发目标；并提出了一种适合工程实现的自适应算法。 基于该模型，结合P2P服务调度算法和内容分发的QoS传输机制及算法，提出了针对基于专网的P2P网络环境下内容快速分发的端到端解决方案，包括内容的上传、存储和内容的指定分发。同时，在工程实现上提出了相应的具有媒介存储功能的DVR（Digital Video Record，数字录像机） IP机顶盒的低成本终端的实现方法。在端到端解决方案和DVR IP机顶盒的协同下，实现了内容的快速、安全分发。端到端解决方案的控制中心在任意时刻可以对指定DVR IP机顶盒或机顶盒组，在指定时间以指定版式播放指定内容。而且，控制中心可以实时监视并控制每一台DVR IP机顶盒的工作状态和运行状况，实现了头端对终端的完全掌控，做到了精细控制粒度。
英文摘要	In the Internet, FTP and HTTP are the two main technologies for content distribution. However, they can not solve the obstacle that distributing content to large number of terminals quickly. With the number of terminals increasing, the download speed of each terminal decreases. On the contrary, P2P (Peer to Peer) technology can distribute vast content to each terminal efficiently and quickly. Furthermore, with the number of terminals climbing, the download speed of each one is in the way of rising. Nowadays, P2P is used widely, particularly in personal fields. It is reported that P2P is one of four core technologies which are changing the Internet. In the content distribution system (CDN) running in P2P network based on private network, it should realize the content distribution quickly, not only for vast data, but also for real-time messages, such as control messages, emergent messages, etc. The objective of this research work is the study of techniques for content distribution in P2P network based on private network. The major jobs are listed as follows. Aiming at the characteristic for the P2P network based on private network, a new system model is established. The model is using for the following system design, rectifying and validation. It helps to realize content distribution quickly, efficiently, and exactly, both for common and individual content, with the environment in which a mass of points of network connect via very different Internet access ways. In the content distribution system, there are many kinds of tasks and there are a great number of tasks for each kind of task. Meanwhile, the time-sensitivity for each task is different, and the data included for each task is also different. To dispatch all these tasks well, with the characteristic of P2P technology, a new P2P service control method based on priority is proposed. The new method inherits some measure of Earliest Deadline First (EDF) method and Ant Colony Optimization (ACO) method. The new method includes task priority control, proxy service priority control, and priority dynamic updating control. The new method is simple, independent, high efficiency. And it is also adapting to various kinds of tasks, data, priority, etc. Moreover, for the IP network is a do-best network, therefore, a new transfer mechanism to improve quality of service (QoS) in content distribution is proposed. It can be used in the network in which the Internet access speed for the terminal is poor or the Internet access time is limited. The new transfer mechanism adjusts download method automatically by the priority, data, and the number of terminals for the distribution task. It ensures the content reaching all terminals in least time. With the model, P2P service control method and QoS transfer mechanism, an end-to-end content distribution solution is proposed, which running at P2P network based on private network, including content’s upload, storage and individual contribution. And that, the engineering realization also includes a new low cost digital video record (DVR) IP terminal - set top box (STB). With the cooperation of end to end solution and DVR IP STB, the content distributes quickly and safely. The control center of the solution can let any STB in the given time playing the exact content in appointed format. Withal, the center monitors and controls the status of each STB. In other words, the head-end controls the terminals completely.
语种	中文
公开日期	2011-05-07
页码	73
内容类型	学位论文
源URL	[http://159.226.59.140/handle/311008/464]
专题	声学研究所_声学所博硕士学位论文_1981-2009博硕士学位论文
推荐引用方式 GB/T 7714	潘海斌. 基于专网的P2P网络缓存拓扑建模的方法和工程实现[D]. 声学研究所. 中国科学院声学研究所. 2009.

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