非结构化P2P网络中基于物理位置与Bloom-filter的副本一致性维护机制

拥有一个有效的一致性维护机制是保证P2P系统正常运行的关键之一。非结构化P2P系统中的消息传播主要通过邻居的转发,会产生大量冗余消息;并且,系统中节点的物理位置和逻辑位置存在着不匹配,会增加消息传播的时间开销。为减少一致性维护代价,该文提出基于物理位置与Bloom-filter的副本一致性维护机制。该机制利用复杂网络中社团划分思想,将网络中的节点按物理位置划分成多个簇,簇中节点物理位置相近,让更新在簇内进行;再引入双层Bloom-filter和冗余二级邻居改进现有更新消息的传播方法。实验表明,该机制可以降低更新消息的冗余传播和一致性维护的时间开销。     

基于随机进程代数的P2P网络蠕虫对抗传播特性分析

 研究P2P网络中良性蠕虫和恶意蠕虫在对抗传播过程中的特性,可为制定合理的蠕虫对抗策略提供科学依据.提出一种基于随机进程代数的P2P网络蠕虫对抗传播的建模与分析方法.首先,分析了传播过程中蠕虫之间的对抗交互行为以及网络节点的状态转换过程;然后,利用PEPA语法建立了恶意蠕虫初始传播阶段与蠕虫对抗阶段的随机进程代数模型;最后,采用随机进程代数的流近似方法,推导得到能够描述蠕虫传播特性的微分方程组,通过求解该方程组,分析得到P2P蠕虫的对抗传播特性.试验结果表明,良性蠕虫可以有效遏制P2P网络中的恶意蠕虫传播,但需要根据当前的网络条件制定科学的传播策略,以减少良性蠕虫自身的传播对网络性能的影响.     

P2P文件共享系统中对等点发现机制的实现

由于P2P网络的动态性，如何有效和准确地进行对等点定位成为P2P网络中的关键技术。本文在分析现在P2P网络中几种常见的对等点发现机制的优点与不足的基础上，提出了利用IP多播技术和JXTA平台实现的对等点发现机制，并讨论了其在P2P文件共享系统中的实现方法。     

基于P2P网络的Web服务发布模型研究

为了突显P2P和Web服务的优势,基于JXTA平台的核心协议和Web服务的体系架构,建立了P2P网络中的Web服务发布模型,该模型通过利用管道、通告等JXTA协议机制实现了Web服务的SOAP消息的打包,完成了P2P网络中的Web服务的发布和请求及其协同工作.本模型通过JXTA协议的二次开发实现了将Web服务发布到P2P网络中的各对等点上,在一定程度上实现了P2P和Web的融合.     

基于Region多层结构P2P计算网络定位服务策略研究

运用基于Region多层结构P2P计算网络具有小世界模型的特点，提出了基于标准Gossip算法的分级搜索包扩散策略Multi-layer Gossip和Region间基于正六边形的蜂窝路由探测算法，把网络中的消息包分为基于Region间和Region内扩散两类，通过控制消息扩散数K和消息发送轮次数i，实现消息包的高速扩散，使定位某种服务的工作量和查询范围从网络中的所有结点数降低到Region内的节点数，有效地防止恶意请求引发的洪。通过模拟分析，Multi-layer Gossip扩散效率趋于理想状态，消息最多经过O(log√n/m^1 e)完成Region内扩散。     

移动环境中的P2P应用

P2P是目前因特网中广泛应用的资源查找和组织方式,随着移动终端设备的发展,移动环境中的P2P应用引起广泛关注。文中对现有移动通信环境中的P2P应用面临的困难进行了研究,介绍通过多媒体消息(MMS)、扩展eDonkey体系及移动代理服务器(Mobileproxy)实现移动环境中P2P应用的方法,并简单介绍了移动AdHoc网络中的P2P应用及蓝牙技术实现移动环境中的P2P应用,然后对移动环境中P2P应用的发展前景进行了展望。     

一种基于P2P技术的网络管理系统的设计

文章首先分析了传统对等(Peer-to-Peer,P2P)网络模型存在的优缺点,并在此基础上提出一种改进的P2P网络模型,如丢弃已见过的消息、原路返回应答消息和设置广播的半径等.同时,对网络模型中的节点管理功能模块、资源搜索功能模块和下载管理功能模块等做了较详细的介绍;文章作者在此基础上,设计、开发了一种基于P2P的网络管理系统(NMS).     

P2P网络资源传播模型分析及监测

P2P网络传输是当今互联网中最主要的应用之一,它的流行使得互联网上资源的共享变得十分便捷,同时也使得传播控制和信息监管变得十分困难。这里以经典的病毒传播模型为基础,提出了一个复杂、快速及大范围网络的传播模型,实现了一个针对BT和eMule下载的传播监测系统,该系统可以对某个资源的网络传播进行扩散趋势预测和节点定位。该传播模型配合监测系统能够对P2P网络资源传播进行有效的监控和预测分析,使管理者能对网络进行更加有力的监管。     

基于P2P技术的网格资源发现中覆盖网络的构建

文章针对网格环境下的集中式资源发现机制的不足,设计了基于P2P技术的资源发现模型,并在分析典型P2P系统Gnutella覆盖网络构建方式的基础上,提出了网格环境下进行覆盖网络构建的新方式--定序方式.按照定序方式构建的覆盖网络可以保证资源发现的服务质量,同时定序方式以节点间的网络延时作为覆盖网络构建的依据,请求消息按照小的网络延时路径在覆盖网络上传播,从而可以提高资源发现的效率.     

基于P2P架构的分布式虚拟环境中一种状态消息的随机分发方法

针对基于P2P通信架构的分布式虚拟环境中的视图一致性问题,在分析有限的网络带宽等影响因素的基础上,提出了一种随机广播算法进行状态消息分发.该算法需预先建立随机几何图结构,并利用给出的通信限制时延进行状态更新消息的发送.结合基于贪心的路由选择算法,通过已获得状态更新消息的节点转发,进而确定节点间的转发路由,获得节点间具有较少通信时延的消息传播时间.经实验分析及验证表明,该算法与其他几种算法相比较而言,在很大程度上减少了时空不一致性事件率,提高了系统性能.     

Dynamics of a rumor‐spreading model with diversity of configurations in scale‐free networks

In this paper, we propose a new rumor‐spreading model, which is a variant of the susceptible–exposed–infectious–removed epidemic model. We consider the influences of the diversity of configurations as a defense strategy to diminish the damage brought by rumor diffusion. The diversity of configuration can be found in different instant messengers or social networks. Moreover, we apply two kinds of the rumor immunization strategies such as random immunization and targeted immunization and show that targeted immunization is better than random immunization for rumor‐spreading control in scale‐free networks. We carry out the systematic analysis of the model and study the local and global stability of rumor‐free equilibrium. In the proposed model, we introduce two new states, namely, hibernator and stifler2, to study dynamical behaviors of the model. The proposed model combines both targeted immunization and diversity of configuration to prevent rumor spreading. By numerical simulations, we indicate that our model is appreciably better than other models in terms of declining the rumor diffusion speed. Furthermore, we investigate many related dynamic properties to make the result more complete. Simulation results show the effect of different parameters on the rumor diffusion in scale‐free networks; meanwhile, numerical simulations confirm the theoretical solution. Copyright © 2015 John Wiley & Sons, Ltd.     

P2P与三网融合

随着互联网的迅猛发展,P2P技术在互联网上的应用超过了Web而成为在流量上占据统治地位的新型应用。同时,P2P技术的影响力不仅限于互联网,还间接地延伸到了电信网和广电网。使用P2P技术的新业务对传统领域带来冲击的同时,也协助解决了三网融合的技术瓶颈。ENUM技术作为跨越互联网和电信网的基础性架构,是融合网络的一条重要的技术途径。将ENUM技术与P2P相结合,可以使P2P共享的优势延伸到电信网络,加速网络融合。     

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.     

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。     

A group-based data-driven approach for data synchronization in unstructured mobile P2P systems

This paper addresses the problem of data consistency on mobile peer-to-peer (MP2P) systems (or MP2P networks). The considered MP2P system is based on a mobile ad-hoc network, where the energy and connectivity on the mobile devices are limited. Since different mobile nodes may store copies of shared information, data synchronization on an MP2P system becomes crucial and challenging due to frequent disconnection and change on network topology caused by node mobility. We propose an effective approach to improving the performance of data synchronization with a dynamic inverted data indexing structure and group-based data-driven consistency management. The proposed approach can effectively synchronize the data items without using a central cache node in each group (or cluster) and perform well in terms of the coverage of successfully synchronized nodes and the number of redundant messages. Last, the proposed approach is validated through extensive simulation experiments.     

Peer-to-peer: is deviant behavior the norm on P2P file-sharing networks?

P2P file-sharing networks such as Kazaa, eDonkey, and Limewire boast millions of users. Because of scalability concerns and legal issues, such networks are moving away from the semicentralized approach that Napster typifies toward more scalable and anonymous decentralized P2P architectures. Because they lack any central authority, these networks provide a new, interesting context for the expression of human social behavior. However, the activities of P2P community members are sometimes at odds with what real-world authorities consider acceptable. One example is the use of P2P networks to distribute illegal pornography. To gauge the form and extent of P2P-based sharing of illegal pornography, we analyzed pornography-related resource-discovery traffic in the Gnutella P2P network. We found that a small yet significant proportion of Gnutella activity relates to illegal pornography: for example, 1.6 percent of searches and 2.4 percent of responses are for this type of material. But does this imply that such activity is widespread in the file-sharing population? On the contrary, our results show that a small yet particularly active subcommunity of users searches for and distributes illegal pornography, but it isn't a behavioral norm.     

基于朋友相关性的P2P快速搜索算法

如何高效地搜索资源是P2P网络中最为关键的问题。对等网络拓扑结构往往不是简单的结构化或非结构化,采用单一的搜索方式效率低下,因此,提出一种改进的搜索算法——基于朋友相关性的搜索算法(FriendSearch),将基于结构化的Chord搜索算法与非结构化的洪泛搜索算法有机结合起来,在网络节点间建立朋友关系。实际系统应用表明本算法较常规Chord算法高效,准确。     

一种移动P2P网络环境下的动态安全信任模型

信任是移动对等(MP2P)网络安全中首要解决的关键技术问题.由于MP2P网络环境与P2P网络环境有本质的区别,因此现有P2P网络信任模型并不适用于MP2P网络环境.本文提出一种适合MP2P网络环境的动态安全信任模型DSTM_MP2P.DSTM_MP2P包括两种方案,一种是针对节点的信任信息已知或部分已知的情况,提出基于节点行为的节点类型识别机制;另一种是针对节点的信任信息未知的情况,提出基于贝叶斯博弈的节点概率选择策略.通过理论分析和实验证明,无论MP2P网络环境如何,DSTM_MP2P模型使得请求节点总是优先连接安全可靠的节点,从而极大地提高了下载成功率.     

P2P流量检测技术与分析

P2P技术及其应用的快速发展增加了网络的负载,影响了网络的性能,因此,对P2P流量进行分析及控制十分必要。在介绍P2P流量检测技术的基础上,对目前几种主流P2P流量识别技术进行比较和分析,指出了各种技术的优势和不足,阐明了流量检测技术的发展方向,提出了一种将不同检测方法相结合以满足一定准确率和效率的思路。