基于分布式缓存管理架构的P2P VoD系统

针对P2P VoD系统中怎样有效的管理和使用节点所缓存的媒体内容的问题,本文提出了一种基于分布式的缓存管理架构。在这一架构中,每个节点存储媒体文件相应的分块,所存储的媒体分块可以组合成一个完整的媒体文件,其所有节点分布在一个环内。因此,在一个环内可以快速定位到这个媒体文件的不同分块,提高了资源搜索的效率。仿真证明这种架构可以有效地管理和使用节点所缓存的媒体内容,支持用户的VCR操作。     

基于双层P2P架构的VoD系统

本文提出的视频点播系统基于双层P2P架构实现,由城域网与驻地网媒体内容分发构成2级数据分发服务平台,用户终端点播并接受视频服务的同时,还能为其他用户提供数据服务,双层P2P架构有效地扩展了系统带宽,增强了服务能力,降低了系统成本,并提供QoS保证.     

基于P2P技术的多媒体网络会议模型

本文提出了一种基于P2P技术的多媒体网络会议设计模型,该模型采用Chord协议组织节点和实现节点路由定位,将服务器的职能分布到P2P Overlay的各节点上,并根据节点的异构性将它们分为普通节点和超级节点,各节点根据自身能力各尽所能,使网络资源得到充分利用,可有效解决C/S模式下中央服务器带来的性能瓶颈问题.仿真实验表明该网络会议系统模型具有负载均衡、易于扩展和高效的资源定位等特点.     

P2P缓存系统中总开销最小的协作缓存策略

为降低P2P缓存系统中的全局开销,提出一种基于总开销最小的协作缓存策略。该策略综合考虑P2P缓存系统中的传输开销和存储开销,使用跨ISP域间链路开销、流行度、文件大小、存储开销来衡量文件的缓存增益。需要替换时,首先替换掉缓存增益最小的内容。实验结果表明,所提策略能够有效降低系统的总开销。     

一种可扩展的分布式VoD系统

传统的集中式VoD系统受到磁盘I/O、网络带宽等因素的限制,无法满足大规模VoD应用的要求.提出了一种可扩展的分布式VoD系统结构,并着重分析了动态扩展和负载平衡特性的实现.对系统的测试数据说明了分布式VoD系统结构在大规模VoD应用中的优越性.     

一种基于P2P的分层分布式自组织网络管理方法

文章提出一种基于对等网络(P2P)的自组织网络管理方法,采用普遍采用的通过分簇的结构来减少管理所带来的信息流量。论文主要讨论了自组织网络管理的体系结构和基于P2P的网络管理流程,通过簇头之间建立的P2P通信来维护整个网络的动态信息,以适应网络拓扑结构动态变化的自组织网络管理。     

基于重定向技术的P2P列表缓存系统研究

提出一种基于重定向技术的P2P(peer-to-peer)列表缓存系统,介绍了系统的设计原理、基本工作原理、软件设计和测试环境.该系统通过对BT客户端发送区域列表文件的方式,减少重复数据片断的网络出口传输,从而控制整个网络出口的P2P流量. 测试结果表明:本系统性能稳定,可以在保证用户正常上网体验的同时,大幅减少网络出口流量.     

一种基于P2P系统的分布式信任模型

在P2P环境中,信任管理是一个新颖而又重要的安全问题。提出了一种基于P2P系统的分布式信任模型,该模型在Chord协议的基础上进行扩展,采用了一种新的信任值发布、查询、获取的方法,信任值的计算与更新的过程,采用了全局信任值和局部信任度合成的方法。分析表明该模型能够满足信任值的安全管理需求,保证了在开放分布的P2P环境下信任值的存储,更新,和获取的安全性,为信任管理研究提供了一种新思路。     

基于S3C2410的VoD系统构建

介绍了一种基于三星公司的S3C2410处理器、开源Linux操作系统的VoD系统构建方案。详细介绍了嵌入式Linux系统的构建,qt/embedded开发环境的建立,主控界面的编写以及应用程序的移植。实验证明,构建的系统能够稳定、流畅地播放视频,具有一定的实用价值。     

基于P2P的CDN新型网络及缓存替换算法

对内容分发网络和P2P网络的特点进行了分析,给出了一种基于P2P的CDN新型网络自治缓存系统的体系结构,提出了自治缓存区域中智能缓存替换问题并给出了智能缓存替换方法和双关键字缓存替换算法.通过仿真实验,可以找到以运算复杂度低命中率高的关键字来实现缓存替换.     

Distributed upload bandwidth assigning algorithm in P2P VoD system

In a peer-to-peer(P2P) live streaming system,each peer uses greedy strategy to download chunks as many as possible so as to assure smooth playback and promote the chunk propagation.However,diversity of video playback rate,heterogeneity of peer downlink bandwidth and no prefetching limitation determine that greedy strategy is not the best strategy for P2P video-on-demand(VoD) system though this strategy performs well in P2P live system.To reasonably assign upload bandwidth among peers,we first present a stochastic model to relate expected downloading speed(EDS) with buffered data amount(BDA,the amount of data has been fetched in buffer,however has not been played yet by the peer),video playback rate and fluency(the probability of no interruption in a viewing process).On the base of this model,we design an equal fluency bandwidth assigning algorithm(EFBAA).In this algorithm,requesting peers compute EDS according to several local parameters(such as BDA,video playback rate and fluency) dynamically and independently and send the EDS to neighbor peers together with buffer map.Then the neighbor peer proportionally partitions and assigns its upload bandwidth to requesting peers according to their EDS.Extensive simulations demonstrate that EFBAA outperforms greedy strategy in terms of server load and startup latency.     

Modeling and application of moderate prefetching strategy based on video slicing for P2P VoD systems

In peer-to-peer (P2P) video-on-demand (VoD) streaming systems,each peer contributes a fixed amount of hard disk storage (usually 2 GB) to store viewed videos and then uploads them to other requesting p...     

Model of downloading strategy from peers and server for saving server bandwidth in P2P VoD system

In peer-to-peer(P2P)video on demand(VoD)system,once the P2P downloading rate cannot satisfy the need of playback,server is quickly referred to for help in providing enough bandwidth.Thus the switch of downloading from other peers(P2P)and server(HTTP)exists.This paper uses the proportion of P2P downloading amount(PPDA)during the video watching process to measure server load.This article is interested in finding a better strategy or switch rule between P2P and HTTP downloading for saving server bandwidth.The authors suggest and model a kind of switch rule based on local buffer amount,using mathematical theory of Brownian motion.It can effectively alleviate the impact of P2P rate fluctuation,reduce the switch times and improve the PPDA by at least 3%-5% on the basis of the former switch rule,which means substantial cost can be saved.Particularly the PPDA is related with the ratio of playback bit rate to the HTTP downloading rate which means the PPDA can be restricted by controlling the ratio in the real-world system.Though the result comes from constant bit rate(CBR)video supposition,it provides perspective and method for variable bit rate(VBR)application,and valuable insights for the future development of P2P VoD system.     

Distributed Storage-Assisted Data-Driven Overlay Network for P2P VoD Services

Providing VCR-like operations in Peer-to-Peer (P2P) environments is a significant challenge. This paper proposes a distributed Storage-assisted Data-driven overlay Network (SDNet) to support P2P Video-on-Demand (VoD) services. It integrates two networks: a Data-driven Overlay Network (DONet) and a multi-way tree. DONet is enhanced and used for the routine video distribution based on the buffer overlapping mechanism and gossip protocol. A novel algorithm which uses a multi-way tree structure and extra pre-fetching buffers at the nodes is proposed to support efficient VoD operations. Videos are divided into uniform segments, pre-fetched and stored in a distributed manner along the tree topology. The cooperation between DONet-based video delivery and the tree-located multimedia components enable multimedia streaming interactive commands to be performed efficiently. This paper presents and discusses the structure of SDNet and the distributed storage scheme and details the cooperation procedure. Simulation-based testing results show how the proposed SDNet is an efficient interactive streaming solution in a P2P environment.      

面向大规模汇聚接入网的分布式VoD服务的性能仿真

 流媒体应用有着实时性、连续性、带宽消耗大等特点,对传输网络提出了较高的要求.用户接入网作为传输网络的重要组成部分,对流媒体服务质量有重要影响.新一代高性能宽带信息网的试运行,初步验证了大规模汇聚接入网络技术在某些条件下支持流媒体的有效性.然而,由于某些限制,在试运行中还不能实现在大规模用户并发访问流媒体服务器的条件下的验证,而在仿真中却可以实现这种验证.在本文中,我们对于面向不同接入网的分布式VoD系统作了仿真比较.结果表明,面向大规模汇聚接入网的VoD系统在接入路由器无拥塞时,在相同的硬件成本下,在端到端时延及其抖动指标上有较大的提高.     

适应异构网络环境的VoD系统

提出了利用协议无关的函数和结构设计视频点播(VoD)系统的方法.实验表明:通过该方法构建的VoD系统具有良好的网络自适应性.     

VoD群集系统的设计与实现

提出了基于数字电视VoD群集系统的体系结构，实现了数据存储、视频服务器调度、视频播出、数据缓存和各功能模块的进程通信，并应用于视频点播系统。     

VoD系统典型视频服务器性能分析

视频服务器是VoD系统中最重要的组成部分,不同厂家的视频服务器由于采用的体系结构以及开发策略不同,其产品之间存在着较大的差异.通过对若干种典型服务器产品的体系结构进行分析比较,总结了它们的性能特征、服务能力和应用领域.     

Blocking Probability Based Hierarchical Storage Design in VoD Systems

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