P4P：P2P的替代者

P2P网络的出现,成功地实现了可扩展的网络应用设计,并且已经成为一种新的范式。然而,P2P也面临着如何高效和公平地利用网络资源的挑战。特别是,缺乏明确地与网络供应商进行沟通,P2P的应用程序可能会消耗太多的带宽,使网络运营商负担不起,导致供应商采取很多限制P2P的措施。文章提出了一个简单,轻量的P4P结构,以便更有效地与网络供应商合作,最终更加高效地利用网络资源。     

由P2P技术展望P4P

P2P技术在短短几年之内经历了从初生到成熟再到大规模普及的飞速发展,其为广大互联网网民带来了极为丰富的资源和高速的体验,然而面对P2P带来的侵犯版权、信誉以及隐私保护等问题,P4P技术的出现似乎带来一些生机。本文从当前P2P技术的基本情况、面临难题谈起,介绍了P4P技术的原理,并对其发展前景做了展望。     

P2P技术

本文简要介绍了P2P技术的实现原理.文章以对SKYPE软件进行黑盒分析的结果为基础,深入剖析了SKYPE的实现技术,包括网络结构、呼叫接续、被叫寻址以及语音编码等各方面.对研究P2P语音技术的人员有一定的参考价值.     

P2P运营模式及P2P业务发展策略

目前主要P2P业务的运营模式主要有:Skype模式、广告模式、商贩模式、网格计算模式、电子商务模式。这些业务运营模式可以降低应用提供门槛,实现系统自激励机制,实现资费分担,增加用户"黏"度。未来,P2P的一个可能的方向是平台化,即形成一个基于P2P的资源交换平台,这个平台对用户进行抽象,对资源进行统一建模,并以一致的方式进行资源标识、注册、索引和搜索。用户之间的交互协议,可以采用标准的会话初始化协议(SIP)方式进行,实现标准化。交互接口可以按照可扩展标记语言(XML)的方式进行定义。不同的应用将基于这个平台构建不同的资源交换模型,并生成不同的应用逻辑。     

金鹏P2P流量管理解决方案——从容应对P2P冲击

P2P技术，即对等网络技术，是指网络主机在充当客户端获取资源的同时充当服务器向其他对等体提供服务。随着计算机网络的广泛应用和多媒体资源的日益丰富，P2P技术被主要应用于大型的多媒体文件共享方面。当前用于文件共享的P2P协议种类很多，在美国大量使用的是KaZaA，在欧洲存在大量用户的是eDonkey和WinMx，在我国使用最频繁的是BitTorrent，其他常用的P2P协议还有如FastTrack、eMule、Grokster、Groove、Gnutella等。P2P用户的总数数以百万计，占用的带宽资源也高达70％以上。     

P2P流媒体技术

P2P技术是一种打破了传统的Client／Server模式，基于对等节点非中心化服务的平台方案。其“去中心化特点符合WEB2．0技术潮流，特别在流媒体领域，由于采用Peer之间对等计算的模式，大大提高了资源共享的利用率，能在较低的成本下，充分利用空闲时间分发数据，避免拥塞，提供具备高实时性、容错性能的流服务，为流媒体开辟了一条崭新的道路。     

P to P和软交换

电话网发展的第一阶段是逐步过渡到以软交换为核心的网络,但软交换在许多地方沿用了电话网的思路,并不是纯粹以IP为基础通信网的最佳选择。它作为电话网向IP网演进的权宜之计和过渡方案而登场,但是IP网的无连接特性和开放性注定了软交换的作用将是昙花一现的;未来发展的趋势是网络将趋于简单,而终端将越来越复杂,功能越来越强大;在电话网发展的第二阶段,在纯IP的环境中具有更高效率的通信模式,将会成为通信的主流。     

P to P和软交换

电话网发展的第一阶段是逐步过渡到以软交换为核心的网络，但软交换在许多地方沿用了电话网的思路，并不是纯粹以IP为基础通信网的最佳选择。它作为电话网向IP网演进的权宜之计和过渡方案而登场，但是IP网的无连接特性和开放性注定了软交换的作用将是昙花一现的；未来发展的趋势是网络将趋于简单，而终端将越来越复杂，功能越来越强大；在电话网发展的第二阶段，在纯IP的环境中具有更高效率的通信模式，将会成为通信的主流。     

P4P技术简介

与传统的两种思路,即P2P应用感知物理网络状况,或者运营商网络限制P2P流量不同,P4P将P2P应用和承载网联合设计,一方面使P2P应用利用网络的能力得到提升,另一方面减少了网络骨干线路上的负载,从而显著地提高ISP的网络效率。本文从P4P的背景、起源、架构、发展前景等方面对P4P进行了介绍。     

实时识别P2P-TV视频流的方法研究

基于P2P的IPTV(P2P-TV)是当前发展最为迅速的因特网应用之一,实时识别P2P-TV视频流是管理网络P2P-TV流量和理解网络行为的关键一步。通过分析以PPLive为代表的P2P-TV体系结构、通信过程、报文结构以及系统特征,该文提出了一种实时的基于爬虫的识别视频流CIVF算法和一种实时的基于协议特征的识别视频流PIVF算法,CIVF算法通过爬虫程序获取P2P-TV节点信息来识别P2P-TV视频流,而PIVF算法则基于视频流的通信时序和应用层负载特征实现实时识别。在因特网环境的试验分析结果表明,CIVF算法具有实现便捷但识别率不够高且节点信息残存时间较长的特点,PIVF算法则具有准确率较高、识别速度较快和扩展性强的特点。     

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...     

Inferring Network-Wide Quality in P2P Live Streaming Systems

This paper explores how to remotely monitor network-wide quality in mesh-pull P2P live streaming systems. Peers in such systems advertise to each other buffer maps which summarize the chunks of the video stream that they currently have cached and make available for sharing. We demonstrate how buffer maps can be exploited to monitor network-wide quality. We show that the information provided in a peer's advertised buffer map correlates with that peer's viewing-continuity and startup latency. Given this correlation, we remotely harvest buffer maps from many peers and then process these buffer maps to estimate the video playback quality. We apply this methodology to a popular P2P live streaming system, namely, PPLive. To harvest buffer maps, we build a buffer-map crawler and also deploy passive sniffing nodes. We process the harvested buffer maps and present results for network-wide playback continuity, startup latency, playback lags among peers, and chunk propagation patterns. The results show that this methodology can provide reasonably accurate estimates of ongoing video playback quality throughout the network.     

IPTV over P2P streaming networks: the mesh-pull approach

IPTV, an emerging Internet application, would revolutionize the entertainment and media industries; however, IPTV also has the potential to overwhelm the Internet backbone and access networks with traffic. To date, IPTV over P2P streaming networks has advanced significantly using two different approaches: tree-push versus mesh-pull. In particular, the mesh-pull streaming approach has achieved a number of successful commercial deployments. In this article, we examine the current progress in the research and development of mesh-pull P2P streaming systems. We provide an overview of the general mesh-pull streaming architecture and review various challenges, design issues, and interesting research problems in this approach. We discuss the construction costs for providing an IPTV service with service guarantees. We outline a measurement technique for monitoring the video playback quality of mesh-pull streaming systems. We emphasize that the future P2P IPTV systems should be designed to meet the expectations of users for quality-of-experience. We also identify a few other important issues for IPTV over P2P streaming networks, including the traffic pressure on ISPs, various security concerns, and the necessity to re-examine the most appropriate P2P architecture. Insights obtained in this study will be valuable for the development and deployment of future P2P IPTV systems.     

P2P技术在IPTV中的应用

IPTV是基于宽带高速IP网的流媒体服务，提出基于对等网络模式的IPTV系统，从而克服了现在IPTV系统的“瓶颈”问题，对P2P技术存在的问题进行分析并提出对策。     

Exploring the accuracy of capturing snapshots in large‐scale P2P IPTV systems

With the growing maturity of peer‐to‐peer (P2P) technology, Internet protocol television (IPTV) applications based on that gained great success commercially and have attracted more and more attentions from both industry and academia. Currently, the active measurement method based on crawler technology is the most popular and effective one to study P2P IPTV systems. Existing measurement results revealed that accuracy of captured overlay snapshots depends on the crawling speed of crawler system. In order to capture more accurate overlay snapshots of P2P IPTV system, we developed a very fast and efficient distributed crawler system using the distributed architecture and peer degree‐rank mechanism. In this paper, we first introduce the architectures of PPTV channel‐list resource distribution and the whole system, which is the most popular and largest instance of P2P IPTV applications nowadays. Subsequently, this paper evaluates the crawling results of two dedicated crawlers capturing from peer‐list servers and ordinary peers, respectively. Finally, we propose a fast and accurate dedicated crawler system based on distributed architecture and peer degree rank for PPTV. The experiment results show that the performance of our distributed crawler system is much better than other existing crawler systems. Specifically, our distributed crawler can track a very popular channel with about 7200 online users in 30 s. It is also reasonable to believe that our distributed crawler system can capture complete overlay snapshots. To the best of our knowledge, our study work is the first to explore capturing accurate overlay snapshots of large‐scale P2P IPTV applications. Our crawler system can provide a good solution for capturing more accurate overlay snapshots of PPTV system and can also be used to help researchers to design crawler systems for other P2P IPTV systems. Copyright © 2015 John Wiley & Sons, Ltd.     

一种嵌入式P2P流媒体播放器的设计

随着基于IP流媒体技术的交互式网络电视得到广泛应用,嵌入式流媒体播放器作为IPTV重要组成部分越来越引起重视。但是目前市场上的很多嵌入式流媒体播放器,如果用纯软件方法实现虽然易于升级和移植,但实时性较差,如果采用专用的编解码算法芯片虽能保证实时性,但系统的灵活性太差,不利于算法升级。本文采用的基于TI公司专为多媒体应用而设计的芯片TMS320DM6446（简称DM6446）为开发平台,使其能兼容正在发展的各种多媒体信号处理标准,构成通用的软件平台,并且采用层次开发方式优化了播放器的逻辑结构,达到易于拓展、升级和高实时性的目的,本文对系统进行了测试并验证了此方案的可行性。     

基于P2P流媒体的教学体系结构研究

随着网络通信和多媒体技术的发展,人们对网上音、视频的多媒体教学内容需求日益增长,基于流媒体技术的远程学习是未来人们受教育的新方法。然而流媒体的质量并不能令人满意,传统的网络教学系统大多采用C/S模式,服务器以单播的形式传输媒体流。结合当前流行的对等网络（P2P）技术和流媒体技术,介绍了如何构建基于P2P流媒体技术的远程网络教学系统的问题。结合P2P网络的优点,对系统中流媒体传输进行了改进,从而降低流媒体服务对骨干网的负载,避免网络阻塞。     

IPTV视频个性化推荐方案

分析了IPTV视频领域个性化推荐需求,以“虚拟视频用户”为基础建立了IPTV视频用户画像,构建了“离线批处理数据分析+在线流式推荐引擎”架构的个性化推荐系统,实现了IPTV视频的个性化推荐。验证结果证明该方案是大数据技术在提升用户IPTV使用体验方面的有益尝试。     

具负载平衡之IPTV影音串流系统

影音媒体具高带宽及实时特性,因此影音串流系统的服务质量的提升端赖影音服务器的有效管理。在此提出一套Video replication及Access request distribution的算法,藉由将热门影音分散到各影音服务器以及影音存取的分散,以达到各影音服务器系统负载平衡的效果。在此比较了3个不同的算法的负载平衡的状况,经实例验证,提出的算法确能达到影音服务器负载平衡的效果,承载更多的系统服务要求。该系统构建在Smart-i TV的IPTV系统台,并讨论了实作的相关技术。