基于爬行器的大规模P2P IPTV测量

为了解大规模P2P IPTV系统中的用户行为特征和拓扑结构特征等内在信息,开发和部署了一个多协议P2P IPTV爬行器TVCrawer,对3个主流的P2P IPTV系统--PPLive,PPStream和UUSee进行了大量的主动测量,并对P2P IPTV系统中的用户行为和网络拓扑特征进行了分析和比较.主要发现包括:1...     

基于P2P 网络的大规模发布／订阅系统

提出了一种大规模发布/订阅系统中基于内容的路由的新途径——ROSE．在一个环空间中,ROSE 沿 着不同的、至少在一个节点相交的分区建立订阅条件和事件的路由．建立了ROSE 的分析模型,仿真验证了所提模 型的有效性．实验结果表明,ROSE 不仅提高了大规模发布/订阅系统的路由效率,同时为在部署时进行流量调节提 供了一个新方法．     

基于P2P网络的大规模视频直播系统

介绍了一种基于P2P(peer-to-peer)网络的大规模视频直播系统Gridmedia.该系统采用Gossip协议构建无结构的应用层覆盖网络,每个节点可以独立地选择自己的伙伴节点.在覆盖网络上,每个节点通过一种推拉结合的流传输策略从邻居节点获取数据.与DONet中的纯拉策略相比,推拉结合策略大幅度减小了终端用户观看视频的延迟,并有效降低了直播系统的控制开销.PlanetLab上的大量实验充分表明了该策略的有效性.Gridmedia的原型系统通过300Kbps的视频码流对2005年春节联欢晚会进行了全球互联网直播.晚会期间,全球范围内有超过500 000人次通过系统观看了直播,最高在线人数达到了15 239人,充分验证了系统的性能.     

IPTV与P2P的结合

针对IPTV所面临的技术瓶颈,阐述了IPTV与P2P技术结合的优势,并描述了相关工作流程。     

P2P在IPTV中的应用

针对P2P技术在IPTV中应用的研究热点,提出了一种基于超级节点的P2P-IPTV体系结构,该结构充分利用了P2P技术在交互式应用方面的优势,使构建更加灵活有效的IPTV业务网络成为可能。     

P2P技术在IPTV中的应用

P2P打破了传统C／S模式服务器对网络资源的集中化管理和提供，解放了服务器响应的压力和降低了带宽负载，应用于IPTV系统。然而P2P技术为IPTV业务实现带来灵活和高效率等优点的同时也带来一些问题，比如时延、网络不可控等。本文就P2P技术在IPTV中的应用及相关问题进行了分析。     

基于P2P技术的IPTV研究

分析了P2P技术和IPTV技术的发展现状和各自特点,研究IPTV在P2P模式下的应用,同时展望了IPTV在新的模式下的发展思路和前景。     

基于种群动力学的P2P IPTV系统内容污染扩散模型

近年来,随着P2P(peer-to-peer)技术的日益成熟,基于P2P技术的IPTV(Internet protocol television)系统逐渐流行并取得了巨大成功,吸引了来自全球产业界和学术界的密切关注.但是,由于P2P IPTV系统自身特有的分布性、匿名性、快速传播性、用户规模大等特点使得其更容易成为攻击的目标.在对P2P IPTV内容污染攻击过程和节点在内容污染攻击中的行为特征进行详细分析的基础上,建立了一个具有种群动力学特征的P2P IPTV系统内容污染扩散模型,该模型充分考虑了在真实世界的P2P IPTV系统内容污染攻击中用户的持续观看行为、用户的加入和离开行为对频道用户规模动态演变的影响.实验结果表明,提出的P2P IPTV内容污染扩散模型可以有效和准确地刻画真实内容污染攻击场景中污染攻击对频道的在线节点规模动态演变和节点离开行为的影响情况.     

一个P2P IPTV多协议爬行器——TVCrawler

P2P IPTV网络测量是研究P2P IPTV行为和特征的重要手段,不仅有利于设计出更符合真实网络环境的系统或协议,也是实现P2P IPTV监测、引导和控制等方面的重要依据和基础。爬行器是P2P IPTV网络的一种主动测量技术,也是目前P2P IPTV测量的主要方式之一。提出了一个P2P IPTV多协议爬行器——TVCrawler,能够对PPLive、PPStream和UUSee三个系统的直播频道进行测量。TVCrawler主要具有三个特点：1）采用基于反馈的引导节点集构造机制;2）采用主从结构,并行爬行获取拓扑数据;3）采用基于拓扑增长系数的自适应爬行时长控制。实验表明,TVCrawler的爬行测量速度达到20~100节点/秒和130~500边/秒。     

A design of IPTV conditional access mechanism based on P2P network

A significant problem in providing IPTV services is its high deployment and maintenance cost. In addition, the capacity of the video servers can quickly become a bottleneck. One solution to alleviate the load on servers is to use peer-to-peer (P2P) technology. In this paper, we propose a conditional access mechanism to protect the copyright in P2P IPTV service. It enables large-scale distribution of copyrighted video using P2P streaming technology. The security and efficiency of IPTV service can be guaranteed in our design.     

基于P2P的IPTV的CAS密钥管理机制

对等网络电视（P2P IPTV）利用对等网络（P2P）的优良特性,有效地降低了服务器端的负载压力、提高了网络电视系统的鲁棒性以及流媒体的分发速度。条件接收系统（CAS）是P2P IPTV系统中十分重要的安全子系统。其中通过对CAS原理、P2P IPTV系统构架的深入研究,在此基础上提出了一种非常适用于P2P IPTV系统的CAS密钥管理机制。     

A novel P2P IPTV system for IPv4/v6 networks

As IPv4 address pool has been completely depleted and the transition from IPv4 to IPv6 has become a trend, P2P video streaming through IPv4/v6 hybrid network is now needed, for equipments with different types of IP addresses widely exist on the Internet. Traditionally, large-scale commercial P2P-IPTV systems have been deployed in IPv4 networks. However, these systems do not support equipments with IPv6 addresses and cannot work in IPv4/v6 hybrid networks. To overcome this problem, we propose a novel dual-stack-based architecture to distribute contents to different networks. The core element of the system is the dual-stack tracker which makes all equipments with IP address interconnect with each other and form a hybrid network. Meanwhile, equipments with IPv4/v6 addresses act as bridges, which distribute contents to IPv4 and IPv6 networks. The paper focuses on how to make all equipments with different types of IP addresses work in one system, analyzing the architecture and performance results related to the use of IPv6 bandwidth. This system has been deployed and broadcasted the 2010 FIFA World Cup South Africa with 755 kbps video stream, and our results demonstrate the feasibility of video over IPv4/v6 hybrid network for a representative application.     

基于混合P2P的端到端网络测量系统

基于P2P的网络测量系统以降低单点瓶颈和部署开销为目标,其中结构化P2P一般假设节点具有相同的能力,不适合大规模部署;非结构化P2P通信负载过大,可扩展性差.因此,本文结合多种P2P模式的优点,引入分层思想,对节点按能力分簇,选取性能佳的作为簇首组成上层高速转发网,由簇首负责维护和管理簇内普通节点,同时描述了系统的初始化构建过程、各个功能模块、自适应维护机制等,并实现了一个系统原型.实验结果表明,该系统实现了节点的自动化部署,同时提高了系统的可扩展性,降低了测量开销.     

基于P2P 的大规模考试平台实例

在大规模考试中,由于同时参与考试的人员众多,考生登录时的试卷分发和交卷时的试卷回收常常因为并发访问量过大而造成服务器崩溃。P2P以节点平等为核心,淡化中心服务器的角色,以高效的方式向需要资源的节点分发内容,能很好的解决大规模考试中因过分依赖于中心服务器而造成的一系列问题。     

P2P网络技术在网络电视(IPTV)中的应用研究

P2P打破了传统C/S模式服务器对网络资源的集中化管理和提供,基于此提出了一种基于超级节点的P2P-IPTV体系结构,该结构使IPTV的实现更加灵活高效,但由于其开放性的特点,给网络的安全性和可管理性带来了一定问题,该文就此进行了分析。     

A Comprehensive and Adaptive Trust Model for Large-Scale P2P Networks

Based on human psychological cognitive behavior, a Comprehensive and Adaptive Trust (CAT) model for large-scale P2P networks is proposed. Firstly, an adaptive trusted decision-making method based on HEW (Historical Evidences Window) is proposed, which can not only reduce the risk and improve system efficiency, but also solve the trust forecasting problem when the direct evidences are insufficient. Then, direct trust computing method based on IOWA (Induced Ordered Weighted Averaging) operator and feedback trust converging mechanism based on DTT (Direct Trust Tree) are set up, which makes the model have a better scalability than previous studies. At the same time, two new parameters, confidence factor and feedback factor, are introduced to assign the weights to direct trust and feedback trust adaptively, which overcomes the shortage of traditional method, in which the weights are assigned by subjective ways. Simulation results show that, compared to the existing approaches, the proposed model has remarkable enhancements in the accuracy of trust decision-making and has a better dynamic adaptation capability in handling various dynamic behaviors of peers.     

基于PayLoad特征的P2P IPTV应用识别

近年来,基于P2P流媒体技术的网络电视已经成为网络舆论传播的重要手段之一,而P2P技术的无中心和自组织特性将大大增加对网络电视服务进行识别和监管的难度.本文首先通过对不同IPTV的payload数据分析,发现P2P IPTV系统通信过程中均存在访问地址特征、协议定义特征以及数据传输特征,然后提出了基于以上三种特征相结合的识别方法,并设计实现了实时识别系统,最后利用统计实验验证了系统的识别精度并对实验进行了分析.     

Network Awareness of P2P Live Streaming Applications: A Measurement Study

Early P2P-TV systems have already attracted millions of users, and many new commercial solutions are entering this market. Little information is however available about how these systems work, due to their closed and proprietary design. In this paper, we present large scale experiments to compare three of the most successful P2P-TV systems, namely PPLive, SopCast and TVAnts. Our goal is to assess what level of "network awareness" has been embedded in the applications. We first define a general framework to quantify which network layer parameters leverage application choices, i.e., what parameters mainly drive the peer selection and data exchange. We then apply the methodology to a large dataset, collected during a number of experiments where we deployed about 40 peers in several European countries. From analysis of the dataset, we observe that TVAnts and PPLive exhibit a mild preference to exchange data among peers in the same autonomous system the peer belongs to, while this clustering effect is less intense in SopCast. However, no preference versus country, subnet or hop count is shown. Therefore, we believe that next-generation P2P live streaming applications definitively need to improve the level of network-awareness, so to better localize the traffic in the network and thus increase their network-friendliness as well.     

PNMS-基于P2P模式的网络测量系统

提出的基于P2P模式的网络测量系统以实现大规模网络端到端测量为目标,借助P2P系统资源共享的特征实现大范围的测量节点部署,提供基于广域网的可靠的网络测量环境。同时通过引入授权机制,为进行统一,有目的性的网络测量提供了较好的支持。数据挖掘和预测系统为网络分析和研究提供了有力的依据。