Validation of H-P2PSIP, a scalable solution for interoperability among different overlay networks

This paper reports the results of experiments from an implementation of H-P2PSIP, a hierarchical overlay architecture based on the ongoing work in the IETF P2PSIP Working Group. This architecture allows the exchange of information among different independent overlay networks through the use of a two-layer architecture based on super-peers and hierarchical identifiers. The validation of this proposal is based on a Linux based real implementation where we have used four different scenarios with 1,000 peers in order to perform different experiments. We have obtained results for different parameters such as routing performance (number of hops), delay, routing state (number of overlay routing entries) and bandwidth consumption.     

Enhancing P2P overlay network architecture for live multimedia streaming

The number of live multimedia streaming applications is increasing, explaining the use of many overlay network topologies. Application-layer multicast (ALM) that it is a feasible alternative to multimedia stream has attracted considerable attention. However, a serious problem of ALM is that the multicast tree may be fragile, and peer failure causes tree partitions. This work presents a novel Hierarchical Ring Tree (HRT) architecture for Peer-to-Peer (P2P) live multimedia streaming. The proposed architecture combines ring-based and tree-based structures in a robust, scalable, reliable and resilient structure that can be used practically as an ALM topology. When peers enter or leave the system, the topology can be recovered rapidly such that live multimedia stream can be delivered smoothly with a low latency. The proposed HRT topology is maintained efficiently without splitting or merging trees. The performance of the proposed architecture and algorithms is evaluated experimentally. Experimental results indicate that the proposed topology can be used in a high-churn P2P network with a small delay. Simulation and experiment results reveal that the proposed architecture has a lower overhead than the ZIGZAG approach when handling peers’ joining or leaving, exhibits faster recovery, better quality-of-service during streaming, and a more robust topology, even with an extremely high number of peers joining/leaving.     

Service-based P2P overlay network for collaborative problem solving

This paper describes a service-based P2P overlay network architecture to support a collaborative environment for solving complex business processes over the network. In the proposed architecture, autonomic service providers corresponding to various activities that occur in the processes reside on the overlay network and are discovered dynamically during the execution of the process. To consummate a specific process, a set of services that map into the business process are federated together and executed in a choreographed sequence. All services have standardized interfaces and this allows any service to be seamlessly replaced with another service without affecting the performance of the federation. The paper presents two cases of application of this architecture, namely, business-to-business collaboration in an engineering environment (General Electric) and multiparty financial transactions (mortgage).     

P2P中基于DHT技术在副本定位策略

为了提高数据网格副本定位机制的负载平衡性和可扩展性,提出分布式hash表直接连续副本散布策略,该机制优化Chord算法,从而起到均衡负载、提高性能的目的.分析和实验表明,该文提出的机制具有良好的性能、可扩展性、灵活性和可靠性,具有较好的实用价值.     

基于等级结构的对等网络激励机制研究

搭便车行为对对等网络造成严重负面影响。首先提出了一种基于等级概念的网络激励机制以抑制搭便车行为并解决公共悲剧问题。所提出的效用函数为公平性特别考虑了用户的绝对贡献值和物理特性,并根据层次分析法来计算它们的值。通过实验仿真证明了此种机制的有效性和实用性,并对此机制的发展给出了展望。     

P2P cloud network services for IoT based disaster situations information

In order to cope with disaster situations properly, it is very important to identify the disaster scale and provide the accurate information of the site to the appropriate authorities including disaster site and Central Disaster Management Center, on-site command post, etc. and share the information provided. In particular, sharing information on disaster situations should control the disaster quickly to prevent the disaster situation from lasting and expanding. However, in the event of a large-scale disaster, delay is caused in the existing commercial network and therefore, the disaster situation cannot be communicated quickly and accurately. In order to determine the situation exactly in the event of a disaster, safety and connectivity of the network and flow of data are very important. Even if the stability of the network and connection of nodes are resolved in the network of each agency business operator, it is necessary to share the platform between networks for IoT/M2M communication for the smooth flow of data. Recently, the disaster safety net of combining existing disaster standard technology with Ubiquitous Technology and Smart IT such as Tetra of Europe, iDEN of the U.S., etc. has been built for disaster safety communications. In addition, systems useful for demand-centered, site-centered immediate disaster response by using Mobile, SNS, cloud computing, etc. are being built and designed to play an important role in the disaster information system especially through IoT, P2P cloud network, big data, etc. Therefore, in this paper, we proposed the P2P cloud network service for IoT based disaster situations information according to the paradigm of the changing times. The proposed service is to combine IoT/M2M network with P2P cloud service for rapid and smooth response in the event of a disaster and provide the results as social services such as SNS. To this end, the wide area wireless disaster information network system has been built in the local and each local network is connected to each other to provide disaster situations by using the server of the disaster area. At this time, each server was to be interconnected via P2P network and to be connected automatically by software-based network in P2P Cloud System. Also, the cognitive cycle was applied for selecting optimal wireless link and router of P2P Cloud-based Disaster Information Network and the danger situations of the disaster area were to be provided to the user by configuring disaster information component for providing services and building central disaster information platform managing it.     

Investigation of a large-scale P2P VoD overlay network by measurements

The proliferation of large-scale Peer-to-Peer (P2P) Video on Demand (VoD) overlays has created the demands to characterize and to understand the emergent properties of P2P VoD applications. In this paper, we investigate the P2P VoD overlay network, spanned by PPLive application, using active measurements. We have developed a piece of measurement software, named as VoDCrawler, to implement the experiment. Different from other existing work, our study focuses on the topology and the churn of the overlay networks. From the study, we have revealed the major features of the P2P VoD overlay networks and have compared them with those in P2P file sharing and live streaming systems. The discoveries we have obtained could help further investigation of the operation of the P2P VoD systems and favor the commercial developments of the P2P VoD applications.     

P2PSIP网络电话系统的研究与实现

针对传统SIP语音软件中心服务器负载过重,无法保证通话质量的问题,提出并研制了一个基于P2PSIP的网络电话系统.该系统采用Kademlia算法作为系统中P2P体系结构所使用的DHT算法,从而搭建重叠网.使用OSIP协议栈实现重叠网上的SIP数据包传输.利用NS2网络仿真器,对加入系统延迟、呼叫时延、等待通话次数以及服务器压力4个方面进行测试,并与基于C/S的SIP软件--xLite进行比较分析.实验结果表明,该系统具有良好的可扩展性,能有效地减少呼叫延迟,提高服务器效率,降低服务器压力.     

基于DHT的P2P网络资源定位算法比较

P2P是一种分布式计算模式,具有较高的可扩展性,可以充分利用网络端主机的计算存储能力,P2P系统是目前网络领域的一个研究热点。目前主要研究结构化的P2P系统,它在可扩展性和资源的定位速度方面均优于以往的P2P系统结构。本文对几种常见的基于DHT的P2P网络资源定位算法进行比较。     

基于P2PSIP的移动实时流媒体系统的安全架构

在分析移动实时流媒体应用对P2P环境提出的安全性方面挑战的基础上,提出了基于P2PSIP的移动实时流媒体系统MPSLSS的安全架构.针对MPSLSS系统的可管控性设计了一种分层混合式P2P网络架构,并采用STRIDE模型举例分析了MPSLSS系统面临的安全威胁,在此基础上提出了一种适用于移动实时流媒体应用的系统安全架构,并对其进行了分析.     

基于Kademlia算法的P2PSIP系统的研究与设计

本文首先概述了基于C/S模式的传统SIP系统的缺陷、P2PSIP系统的由来及发展现状,然后提出了一种构建于P2P层之上的SIP网络电话(P2PSIP)系统的设计方案,其中P2P层采用全分布式哈希表算法Kademlia算法实现;接着重点分析了该方案中DHT(Kad)模块的工作机制以及SIP over P2P中的交互消息;最后给出基于该方案的原型系统的测试结果。     

具有负载分享的P2P IPTV重迭网络的设计

针对在IPTV服务中当网上收视人数大规模增长时网络带宽消耗及服务器负载大大提高的问题,提出了利用P2P(Peer-to-Peer)概念中的应用层群播所形成的重迭网络来解决IPTV负载分享的问题,并通过P2P中Chord路由算法,加速构建与寻找对应的群播代理人节点。实验证明将Chord与应用层群播代理人做有效结合,可以提供用户具有服务质量、扩充性与负载分享的全方位P2P IPTV服务。     

基于P2P覆盖树网络的流媒体传输技术优化研究

PeerCast是一个基于P2P网络的流媒体传输系统,各节点被组织成树状来进行数据的分发.但没有一个有效的机制来维护树的平衡和保证所选取的父节点是最佳的节点.在此基础上,对该系统进行优化,在媒体数据包上加一个字节用来标识当前节点与根节点的距离,并对节点间响应消息进行优化.实验结果表明,这些优化措施能够有效的维护树的平衡和降底数据传输时延.     

A grouped P2P network for scalable grid information services

Information services play a crucial role in grid environments in that the state information can be used to facilitate the discovery of resources and the services available to meet user requirements, and also to help tune the performance of a grid system. However, the large size and dynamic nature of the grid brings forth a number of challenges for information services. This paper presents PIndex, a grouped peer-to-peer network that can be used for scalable grid information services. PIndex builds on Globus MDS4, but introduces peer groups to dynamically split the large grid information search space into many small sections to enhance its scalability and resilience. PIndex is subsequently modeled with Colored Petri Nets for performance evaluation. The simulation results show that PIndex is scalable and resilient in dealing with a large number of peer nodes.

针对P2P网络中DHT的DoS攻击技术研究

本文分析了基于分布式哈希表查找的大规模P2P系统的固有安全问题,提出了一种针对分布式哈希表系统利用算法复杂度进行DoS攻击的方法,并阐述了执行攻击的条件和构造这类攻击的方法,最后结合P2P网络发展趋势总结了此类攻击方法的局限性和进一步的研究方向。     

A scalable P2P overlay based on arrangement graph with minimized overhead

With innovations in the Internet, it is becoming increasingly relied upon. In the last decade, research on peer-to-peer (P2P) technology has become even more popular. As more people use P2P systems, the scalability and flexibility of the systems must be considered. In this study, an arrangement graph is used to form a P2P overlay, the Arrangement-Graph Overlay (AGO), to reduce system overhead and bind routing hops. The proposed AGO utilizes the properties of the arrangement graph, i.e., that each node has a unique ID and IDs between adjacent nodes differ by only one digit, to form the overlay network and develop a routing algorithm. The routing hops of the proposed AGO system can be bound within a certain number because of the diameter of the arrangement graph. Experimental results show that the proposed AGO system can greatly reduce system overhead and perform routing in a constant number of hops, even in a large-scale network environment. The experimental results also show that the AGO system consumes less bandwidth, which is an important consideration in P2P systems.     

一种基于DHT的P2P搜索方法

在网络搜索技术中,P2P模式有C/S模式无可比拟的优势。P2P为非中心化结构中的网络用户赋予更多的权力,使网络应用的核心从中央服务器向网络边缘的终端设备扩散,因而可以全面改写当前的网络搜索技术。在各种P2P技术中,搜索技术是最有价值、最亟待解决的问题,其中分布式哈希表(DHT)协议将是对等网搜索的重要发展方向。本文首先概述P2P搜索技术现状,接着分析比较了当前几种典型的协议搜索方法,最后讨论一种基于分布式哈希表的协议搜索方法。     

一种基于位置信息的P2P路由算法

传统的Peeer-to-Peer（P2P）网络的研究已经基本上解决了分布式网络路由问题,为提高路由的效率,如何有效地缩短路由距离成为当前急需解决的热点.针对这一问题,在分析现有的路由算法的基础上,提出一种基于位置信息的P2P路由算法.算法中结合传统算法和节点所在区域位置的信息,使得网络节点在决定下一步跳转时,优先选择距离较近的节点,从而提高路由效率,减少路由延时.