一种P2P文件共享系统的QoS评价模型

在分析了P2P分层体系结构的基础上,结合P2P文件共享系统应用提出了重叠网络层和应用层的QoS评价模型,并进一步形成了整体QoS评价模型.仿真实验分析了节点的加入和退出、节点的能力和上传策略、节点缓存大小和节点缓存策略等因素对QoS的影响.另外,文件的热度也是影响系统QoS的一个重要因素.     

基于信誉度的P2P反污染机制

文件污染是当前P2P文件共享系统普遍存在的问题,极大地影响了系统的可用性。文中提出一种基于资源和节点的信誉度的反污染机制——R＆amp;Ptrust,其中资源和节点的信誉度是全局计算的。R＆amp;Ptrust还包括隔离主动污染者的惩罚机制和激励被动污染者删除污染文件的激励机制。仿真结果表明,R＆amp;Ptrust能有效的隔离污染者并遏制污染文件的传播,具有良好的反污染性能。     

抗污染攻击的移动P2P数据安全分发系统

采用网络编码方法,给出一个改进的抗污染攻击的安全签名机制,使得签名的私钥能随着传输数据包的改变而改变,运用该安全签名机制设计开发一个移动P2P数据分发原型系统S-SymTorrent.S-SymTorrent以抗污染攻击签名机制作为其数据传输的安全控制策略,不仅获得了较高的传输率,而且确保数据分发的安全性.     

P2P网络污染问题

由于P2P网络的分布性资源共享,不可避免的会给用户管理带来挑战,而网络污染更成为其中制约P2P网络发展的重要问题,已逐渐成为近期P2P网络中一个新的研究热点。尽管P2P网络应用在国内发展异常火爆,但目前国内研究成果并不是很多。文章概述了当前国内外P2P网络中污染现状和比较前期的研究成果,提出了针对污染问题需要研究和解决的一些问题,希望能为从事网络污染研究人员提供一些参考。     

一种基于文件共享的P2P节点认证方案

身份认证是P2P（peertopeer）网络安全的重要组成部分,但传统的PKI（金钥基础设施）认证方式因为具有静态的集中化控制和固定的证书内容等特点,不能很好地满足P2P网络安全认证的需要,且在公钥的分发过程中容易遭受中间人攻击。为此,提出了一种新型的公钥管理架构和身份认证方案,每个节点可以自己产生并分发公私钥,认证服务器仅在节点加入网络时参与完成公钥的分发。超级节点负责管理本组内全部节点的公钥,节点在相互认证时无需认证服务器的参与,仅通过超级节点来完成。分析结果表明,这种认证方案可以有效地抵抗中间人攻击,在保持高效率的基础上又保证了认证的安全性。     

基于P2P的文件共享模型及相关问题的分析

对等网(P2P)技术的提出对当前的客户/服务器(C/S)技术是一种巨大挑战,它相对 于现有网络模型有很多优势.文中对几种典型的P2P技术模型和成果进行分析,包括Napster、Gnutel la、Freenet、JXTA等,对当前存在的问题提出了看法,并对P2P的未来发展进行了展望.     

浅析互联网上P2P网络传输的音视频文件的监管

本文主要介绍了P2P网络的基本工作原理,针对互联网上P2P网络传输的音视频文件的实际情况,以目前常用的P2P下载软件eMule为例,分析了在特定区域内对特定文件的监管方法。     

P2P文件共享系统防止重复下载的方法研究

在P2P文件共享系统中,文件名的差异经常会导致文件被同一节点重复下载,为了降低P2P文件共享系统中摘要算法对文件进行整体和分块处理,下载前先比较文件MD5散列值的方资源重复下载率高的问题,文章提出采用MD5报文法来确定是否需要下载文件,从而有效地防止共享文件被同一节点重复下载.通过分析和利用MATLAB软件进行模拟试验,证明该方法能提高文件的下载效率.     

基于XML/Web Services的P2P文件共享系统的实现

联网计算机之间没有主次之分,各自具有独立的网络自主权,端到端(Peer-to-Peer,P2P)模型能有效地实现计算能力和数字资源的共享和整合.本文介绍一个采用端到端的,层次分布化模型的文件共享系统,定义了关键的系统场景,分析了利用XML/Web Services实现方法,并给出了一个P2P设计模型.     

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。     

一种可控P2P文件下载算法

以BitTorrent为代表的对等网络文件下载时存在带宽吞噬的难题,如何实现可控传输是这类应用可持续发展的必要条件。本文基于电信新业务平台——媒体电信网对可控传输的需求,提出一种可控性对等网络文件下载算法,采用集中式目录服务器传输调度有效限制骨干网负载流量;同时利用基于对等技术的分布式传输,采用空闲终端和补偿服务器相结合的策略进行补偿传输,以保持不低于BitTorrent的下载速率。基于PDNS的数据包级大规模网络并行仿真结果证明了所提出算法的有效性,其综合性能优于BitTorrent算法。     

SKIP:an efficient search mechanism in unstructured P2P networks

Search efficiency and accuracy of resource are important considerations for search algorithm in peer-to-peer(P2P)network.Most search algorithms use flooding among neighbor nodes to search relevant resource.However,this usually causes great amount of redundant messages,which results in high search costs and low search precision.In this paper,we use vector space model(VSM)and relevance ranking algorithms to construct overlay network,and a novel search mechanism search with K-iteration preference(SKIP)based on semantic group for P2P networks is proposed to efficiently solve these problems.The key idea of SKIP is to reorder the semantic neighbors of nodes according to relevant scores and to utilize preference selection during the process of query.We analysis and implement the scheme and reveal that the SKIP provides a low overhead on topology maintenance,which can be effectively used in P2P searching and verify it outperformanee in higher precision and lower search cost by comparing with current semantic-based searching mechanism gnutella-like efficient searching system(GES).     

ACO结合P2P信任模型的无线传感器网络Sinkhole攻击检测

针对无线传感器网络中的Sinkhole攻击问题,提出了一种基于蚁群优化(ACO)结合P2P信任模型的Sinkhole攻击检测(P-ACO)算法.首先,使用蚁群优化算法检测路由中是否存在Sinkhole攻击,并生成传感器节点的警报信息;然后,利用布尔表达式进化标记生成算法为群组警报节点分发密钥,并使用密钥标记可疑节点;最后,计算可疑节点列表中各节点的信任值,将信任值低于预设阈值的节点视为攻击节点.分析表明,相比二分查找算法与基于规则匹配的神经网络(RMNN)算法,该算法在匹配过程中需要更少的匹配搜索次数,提高了算法执行效率.实验结果显示,相比RMNN算法,该算法可以更加准确地检测Sinkhole攻击.     

非集中式P2P系统信任值安全管理的研究

由于P2P系统的开放性、匿名性和动态性,使得实体之间难以确定相互的可靠性。信任值这一概念的引入基本解决了这一问题,同时也使得信任值在整个P2P系统中扮演了至关重要的角色。论文提出了一种能够安全地管理非集中式P2P系统信任值的协议,从而保证了信任值的安全存储、分发、访问以及修改。     

An agent-based incentive mechanism for P2P systems

1 Introduction P2P systems differ from the traditional distributed computing systems. They are self-organizing, distributed resource-sharing networks. In P2P systems, there is no central authority that controls or manages the various components. Nodes can…     

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.     

P2P网络层次化信任模型

大规模文件共享P2P网络中节点之间发生重复交易的可能性较小而难以建立信任关系,从而导致P2P网络容易受到恶意节点攻击。针对该问题本文提出了基于群组的P2P网络层次化信任模型。该信任模型将信任关系划分为群组之间的信任关系,群组与节点之间的信任关系和节点之间的信任关系3个层次。节点利用本地信任信息或所属群组的推荐信任确定给定节点的信任值。仿真分析表明,该信任模型能够有效识别恶意节点,使P2P网络中合作节点具有较高的成功请求率。     

DPFSL:P2P网络的递减概率洪泛算法

Gnutella是一种非常流行的P2P网络模型.由于此网络中采用洪泛算法进行资源搜索,这将导致查询请求指数级增长,加重了网络负载.为解决这一问题,在现有改进算法的基础上,提出了DPFSL算法.它采用递减概率洪泛与自学习相结合的方法,大大减少了查询请求,同时能保证相当高的查询命中率.实验结果表明,DPFSL算法是一种比洪泛算法性能更优越的算法.     

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...     

CDNPatch: a cost‐effective failover mechanism for hybrid CDN‐P2P live streaming systems

Among the most well‐established live media distribution technologies is content delivery network (CDN), which improves user‐perceived quality of service by delivering content from proxy servers deployed at the Internet's edge. In recent years, CDN providers started to tap into their subscribers' peer‐to‐peer (P2P) capacity to alleviate their server costs. Under the inherent peer dynamics, a major challenge of these hybrid CDN‐P2P systems is to provide efficient failure recovery with good quality of service guarantees at a reduced server cost. In this work we propose a cost‐effective failover solution named CDNPatch to address the aforementioned problem. CDNPatch enables peers to periodically precompute a few backup content suppliers by efficient information exchange and maintenance algorithms, and leverages auxiliary CDN servers and an economic server provisioning algorithm to reduce the chance of playback interruption occurring to peers. Our simulation results show that CDNPatch can mask the impact of peer dynamics of 3 real P2P systems, namely, SOPCast, PPStream, and PPTV, with 100 % failure recovery success rate and a failure recovery time less than 1 second at a cost of small P2P communication overhead of less than 1 kilobits per second, while using only 10%, 21%, and 51%, respectively, of the pure CDN scheme's server consumption.