P2P改变通信和传媒世界

先从技术演化的角度怎么看P2P？大家知道互联网从它诞生开始，就在不断进行演化．大家都清楚IETF工作组不断提新的网络协议．改进的建议来改进网络．所谓RFC的建议．实际上互联网最基本的协议是TCP／IP协议．为了适应各种需要．进行了很多改进，提了很多很多的建议。比如MPLS是目前使用最多的标地协议交换。以及IPv6，为了支持移动搞了移动移动IP，为了支持安全有了IPsec．过去互联网不断出现了新的技术。     

移动环境中的P2P应用

1．引言 P2P对等网络是非中心化网络，信息的交换不需要通过创建的中心站点，而直接在对等设备（如个人计算机）间动态地进行信息交换和服务，是一种高效直接的传输方式。P2P打破了传统的C／S模式，各节点对等并可互相提供服务。P2P对等应用在互联网中已经非常普及，并且成为网络资源的巨大消耗者。随着移动数据业务与可承载数据业务终端的普及，以及移动通信网络的快速发展，移动终端与网络结合得越来越紧密，在移动环境中如何实现P2P应用已经引起广泛关注。     

基于P2P的IP电话模型

网络技术的高速发展与普及使其成为信息交互的主要手段。随着网络规模的增大,接入网络中设备的数量和种类也随之增多,然而,这些资源并没有得到充分的利用。如果能有效地利用这些闲置的计算资源、存储能力和网络带宽,将会有效缓解目前互联网上所面临的瓶颈问题。P2P（Peer To Peer）对等网络就是在这样背景下提出的一种网络技术。文中首先介绍了P2P的概念,研究及其应用状况：然后分析了其三种网络模型：集中式P2P、纯分布式P2P和混合式P2P各自的特点和发现机制;最后提出了一种基于P2P的IP电话模型,并详细讨论了该模型的信息模型和搜索策略。     

基于移动P2P网络的移动电视的实现方案

移动电视（Wobile TV）已经成为人们广泛关注的增值业务之一。本文提出一种基于移动P2P（Mobile P2P，MP2P）技术的移动电视业务的实现方式，为了能更好地支持多种类型的移动终端，在网络中加入编码变换服务器，提供实时视频编码变换功能。[编者按]     

移动WiMAX全面挑战3G

IEEE 802．16标准是工作于2-66GHz无线频带的空中接口规范，主要应用于城域网。根据是否支持移动特性，802．16标准又可分为固定宽带无线接入空中接口标准和移动宽带无线接入空中接口标准，标准系列中的802．16、16a、16d属于固定无线接入空中接口标准，而802．16e（正式名称叫802．16—2005）属于移动宽带无线接入空中标准，也被称为移动WiMAX。[第一段]     

一种移动网络中的路由优化模型

本文针对嵌套移动网络中所存在的路由优化问题和数据包多层封装问题,借鉴移动自组织网中的多跳转发思想,提出了一种新型的路由优化模型.在该模型中,移动路由器可以直接选择被访问网络的固定路由器作为自己的外地接入路由器,进而消除了嵌套的影响.分析结果表明,相对于传统解决方案而言,该模型可以有效解决移动网络中由于嵌套而产生的路由优化问题,具有最小的数据包封装开销,并且对安全和快速切换等有着良好的支持.     

移动P2P网络安全拓扑构造协议

针对移动对等(MP2P)网络的安全问题,提出一种MP2P网络安全拓扑构造协议(AMPSTP).AMPSTP协议首先利用Fortune算法完成对地理区域的划分,然后给出临时锚节点的选取和更新策略、MP2P覆盖网拓扑模型的构造和维护机制、MP2P覆盖网的路由发现算法以及基于博弈的MP2P覆盖网的节点选择机制.最后对AMPSTP协议的性能进行理论分析和仿真实验.结果表明,与MADPastry协议相比AMPSTP协议不仅可以保障网络安全和提高网络性能,而且还大大降低了控制开销.     

一种基于中心代理的移动Ad—Hoc网络接入方法

本文针对已有接入方法所存在的缺点,提出一种以移动节点间相互竞争出现的中心节点作为移动代理,利用移动IP协议实现MANET接入Internet的新方法,并对中心代理节点的选取、MANET整体移动接入等问题进行了探讨。该方法具有开销小、接入灵活、不需对移动IP做大的改动等优点。     

面向NGN的无线多媒体智能通信终端及其应用

随着NGN和软交换技术的推进，未来具有复杂计算能力的智能终端设备将取得传统的哑终端。本分析了面向NGN的智能移动终端的硬件体系结构、软件组成、网络通信和协议框架，并给出了一种基于Linux、采用无线局域网接入、支持H．323语音通信的智能通信终端的实现方案。     

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。     

无线Ad Hoc网络中支持P2P应用的研究

无线Ad Hoc网络和P2P技术近年来发展迅速,已经成为宽带无线网络技术领域的研究热点.相关研究表明.在现有的无线Ad Hoc网络中直接应用P2P技术.会造成系统开销大量增加,分组传输效率及查询成功率下降,从而影响整个网络的性能.本文针对上述问题进行分析,采用跨层设计的方法,提出了在无线Ad Hoc网络中实现P2P应用的解决思路和方案,满足无线Ad Hoc网络中各种P2P应用的不同QoS需求.     

引入P2P功能的TD-SCDMA中的无线定位技术

陆地蜂窝系统的发展将引入自组织网络功能，P2P就是支持该项功能的关键一步，无线定位技术是第三代移动通信系统中一个非常有前景的技术。首先，简要介绍了引入P2P功能的，TD-SCDMA系统，并重点对引入P2P的，TD-SCDMA系统中的无线定位技术进行了分析。然后提出了针对其中P2P用户的几种定位方法，最后分析了定位技术如何用于进一步提高系统的性能。     

Network-aware P2P file sharing over the wireless mobile networks

With the coming wireless mobile networks era and the popular use of P2P applications, how to improve the resource retrieval and discovery for P2P file sharing applications in wireless mobile networks becomes a critical issue. In this paper, we propose a novel network-aware P2P file architecture and related control schemes that can provide continuous resource retrieval and discovery for mobile users over the wireless network environment. The proposed architecture divides a P2P file sharing network into multiple network-aware clusters, in which peers are assigned to a network-aware cluster using a network prefix division. Accordingly, there are two designs for supporting mobile peers to retrieve files in wireless mobile networks. First, a novel file discovery control scheme named mobility-aware file discovery control (MAFDC) scheme is devised to obtain fresh status of shared peers and find the new resource providing peers in wireless mobile networks. Second, a resource provider selection algorithm is devised to enable a mobile peer to select new resource providing peers for continuous file retrieval     

Modeling epidemic data diffusion for wireless mobile networks

Data/content dissemination among the mobile devices is the fundamental building block for all the applications in wireless mobile collaborative computing, known as mobile peer‐to‐peer. Different parameters such as node density, scheduling among neighboring nodes, mobility pattern, and node speed have a tremendous impact on data diffusion in a mobile peer‐to‐peer environment. In this paper, we develop analytical models for object diffusion time/delay in a wireless mobile network to apprehend the complex interrelationship among these different parameters. In the analysis, we calculate the probabilities of transmitting a single object from one node to multiple nodes using the epidemic model of spread of disease. We also incorporate the impact of node mobility, radio range, and node density in the networks into the analysis. Utilizing these transition probabilities, we estimate the expected delay for diffusing an object to the entire network both for single object and multiple object scenarios. We then calculate the transmission probabilities of multiple objects among the nodes in the wireless mobile network considering network dynamics. Through extensive simulations, we demonstrate that the proposed scheme is efficient for data diffusion in the wireless mobile network. Copyright © 2012 John Wiley & Sons, Ltd.     

IP2P: a peer-to-peer system for mobile devices [accepted from open call]

Peer-to-peer communications is a major trend in wireless Internet. In a P2P system, the calling peer must identify the network address of the called peer before establishing a P2P connection. This article proposes iP2P, a hybrid P2P system for mobile devices. iP2P utilizes the short message service as the control protocol to identify the address of the called peer. Our approach provides an efficient identification mechanism without the requirement for the maintenance of a centralized registrar server in a hybrid P2P system. We also show how iP2P can integrate effectively with the existing Network Address Translation traversal mechanisms to solve the private IP address issue.     

SNMS: an intelligent transportation system network architecture based on WSN and P2P network

With the development of city road networks, the question of how to obtain information about the roads is becoming more and more important. In this article, sensor network with mobile station (SNMS), a novel two-tiered intelligent transportation system (ITS) network architecture based on wireless sensor network (WSN) and peer-to-peer (P2P) network, is proposed to provide significant traffic information about the road and thereby, assist travelers to take optimum decisions when they are driving. A detailed explanation with regard to the strategy of each level as well as the design of two main components in the network, sensor unit (SU) and mobile station (MS), is presented. Finally, a representative scenario is described to display the operation of the system.     

Efficient data dissemination for Wi-Fi peer-to-peer networks by unicasting among Wi-Fi P2P groups

Recently, the Wi-Fi peer-to-peer (Wi-Fi P2P) technology is discussed to be able to support communications in infrastructure-less network scenarios. In many of such application scenarios, disseminating data (or information) to all network devices is an important issue. According to the Wi-Fi P2P specification, a device can communicate with other devices after joining a Wi-Fi P2P group. A Wi-Fi P2P group is a star network (rooted at a group owner). The group owner can disseminate data to all network devices by broadcasting. However, the Wi-Fi P2P broadcasting mechanism cannot guarantee successful delivery of packets. In order to disseminate data reliably, a possible solution is to disseminate packets to network devices by unicasting. But, by this manner, the group owner will run out of its energy quickly and the time needed to disseminate data to network devices will be lengthened. To consider the above factors, in this paper, we formally define a Wi-Fi P2P data dissemination (WPDD) problem, and prove that this problem is NP-complete. Instead of using one Wi-Fi P2P group to connect all network devices, we propose to divide devices into multiple groups. We then propose a tree-based dissemination scheme and a ring-based data dissemination scheme to achieve data dissemination among groups. The proposed schemes can be compatible with the Wi-Fi P2P specification. We evaluate the performance and effectiveness of the proposed schemes by simulation programs and prototyping implementations.     

Replication schemes for peer‐to‐peer content in wireless mesh networks with infrastructure support

Many mobile devices (e.g., smart phones, PDAs, portable computers) and wireless routers (e.g., WiFi access points) nowadays are equipped with ad hoc transmission mode. In a dense environment such as a college/office campus, this creates the possibility of forming a wireless mesh network (WMN) in which mobile users communicate with each other through multiple wireless hops. This allows mobile users to exchange (share) files over the free access WMN rather than a carrier frequency such as 3G and WiMax. We consider a peer‐to‐peer (P2P) content sharing setting in a WMN, wherein the mesh network operator over‐provision a number of mesh routers in the network with additional storage capacity and P2P‐aware devices that are programmed to cache and store P2P content. Those mesh routers act as caches and participants in P2P content sharing. The aim of this setting is to both reduce the cost of communications between peers within the WMN (i.e., reduce bandwidth and energy that P2P traffic consumes in the network), and enhance the performance of P2P content sharing (i.e., reduce the average P2P content download delay). Our main contribution in this paper is an optimum P2P content replication strategy at the participating mesh routers. In particular, we determine the optimum number of replicas for every P2P file such that the average access cost of all files in the network is minimized. We propose a centralized algorithm that enables the participating mesh routers to implement the optimal strategy. We further propose a distributed (low cost) algorithm for P2P content replication at the participating mesh routers, and show that the distributed algorithm mimics the optimal strategy very well. The analytical and simulation results show that our replication strategy significantly reduces the average overall cost of accessing P2P files in the WMN as compared with other commonly used replication strategies. Copyright © 2013 John Wiley & Sons, Ltd.     

基于P2P的无线传感器网络应用架构研究

通过基础网络互联多个传感器网络，为用户提供大规模、大范围、多样化的信息服务成为未来无线传感器网络的应用模式之一。据此，提出了一种基于P2P（Peer-to—Peer）技术的无线传感器网络应用架构。采用P2P技术，解决了大数据量的通信瓶颈，传感器网络亦可自由加入、变更或退出，方便部署，网络可扩展性好．同时屏蔽底层网络差异及多种接入方式．为用户提供多个访问入口。