基于P2P技术的多媒体网络会议模型

本文提出了一种基于P2P技术的多媒体网络会议设计模型,该模型采用Chord协议组织节点和实现节点路由定位,将服务器的职能分布到P2P Overlay的各节点上,并根据节点的异构性将它们分为普通节点和超级节点,各节点根据自身能力各尽所能,使网络资源得到充分利用,可有效解决C/S模式下中央服务器带来的性能瓶颈问题.仿真实验表明该网络会议系统模型具有负载均衡、易于扩展和高效的资源定位等特点.     

PPmcast: a novel P2P-based application-level multicast using Kamulia

The rapid growth and popularity of networked meeting environments such as video conference in recent years have spawned a series of research interests in constructing large-scale environments. For increasing scalability and decreasing the cost of management and deployment, more and more studies propose using peer-to-peer (P2P) architectures to construct large-scale application-level multicast algorithm for games, multimedia and other applications. In order to improve the applications' performance, high efficiency multicast algorithm is required. This paper focuses on developing a novel P2P application-level multicast algorithm based on Kamulia protocol. In the proposed algorithm, all nodes of P2P network are organized into structured overlay network by distributed hash table (DHT). The distance metric between two nodes is obtained by computing the exclusive or (XOR) value. The theoretical analysis indicates the proposed algorithm has better time complexity degree compared with other similar algorithms. The simulation experiments also show that the proposed algorithm has better performance on the following aspects, control expenses, loss ratio after failure, and waiting time to the first packet.     

P2P视频直播系统改进设计

为了改善P2P视频直播系统的性能,介绍了P2P视频直播系统的相关知识,对比了当前主流P2P视频直播系统的三种主要结构,分析了三种结构各自的优缺点。针对现有大规模直播系统的不足,提出了一些系统改进方案,分别从节省服务器带宽、优化邻居选择策略、充分利用节点上栽性能的角度对现有系统做了改进和优化。利用该改进建议,直播节目的服务提供商能够进一步节省开支,并提供更高质量的服务。     

P2P网络资源搜索算法研究及其改进

随着Web数据量的爆炸性增长,传统集中式搜索引擎已经越来越不能满足人们不断增长的信息获取需求,为新一代搜索引擎提供新的思路,为了资源搜索更具实时性和有效性,提出了基于P2P的搜索方法,分析各类P2P搜索方法的优缺点并阐述其改进思路。通过几种搜索办法的比较,模拟实验结果显示,以达到减少流量开销和缩短查询响应时间比的目的。     

P2PVOD系统中实时资源调度管理的实现

在P2P VOD系统中针对音视频等实时资源的调度管理进行研究,并对媒体资源的发布、查找功能进行实现.构建域内、域间二级架构,用于管理系统中所有客户端上的资源.对客户端发布的媒体资源按照点播的起始时间进行分类管理,以便对媒体资源进行准确快速定位.提出资源参考点的计算方法,增强域内和域间资源的搜索功能.实验平台基于普通局域...     

A pipelined, multiprocessor architecture for a connectionlessserver for broadband ISDN

The direct provision of connectionless service in BISDN calls for servers that are connected to or are part of an ATM network to provide the routing function at input speeds up to 622 Mb/s. Routing is achieved in such a server by changing the VCI/VPI headers in the ATM cells; actual switching is done by existing switches in the ATM network. The paper presents an architecture capable of executing all the functions of a server at input speeds up to 622 Mb/s, scalable to multiple inputs at that speed, making use of processors and special hardware that are available today. To avoid storing large quantities of data, the architecture routes data packets by examining routing information in the initial cell of the packet and routing subsequent cells as they arrive rather than waiting until the complete packet has arrived. It is capable of handling packets that have been multiplexed at the SAR sublayer using AAL Type 3/4 and, with minor modifications, could also handle Type 5 traffic. Arguments are also presented for the use of AAL Type 5 for the direct connectionless service     

UP2P: a peer-to-peer overlay architecture for ubiquitous communications and networking

Approaches to building an intelligent consumerfriendly network have evolved over time from centralized switch-based to router- and serverbased Internet architectures. We propose to drive this evolution further with a new highly scalable architecture that provides features to users derived from the computational and networking capabilities of very large populations of sophisticated terminals. This architecture relies on emerging peer-to-peer overlay technology. We describe a peer-to-peer overlay design that addresses requirements crucial for consumer applications, including overlay federation, peer heterogeneity, peer mobility, and service discovery. In addition, we introduce the concept of an overlay operator and describe the requirements for managed overlays. We have designed and implemented both a middleware and a peer-topeer platform that illustrates these concepts.     

P2P网络管理系统信息模型的设计与实现

为满足基于P2P的网络管理体系结构中管理节点间的协作需求,提出了一种基于语义Web服务和XML的网络管理信息模型.利用P2P通信和语义Web服务,可实现网管服务的分布式注册,服务的统一描述和基于能力的服务检索;利用XML来制订网络管理服务调用的标准,可以实现服务的跨域自动调用.原型实现和运行测试表明,利用提出的模型框架,异构网络管理系统可以通过节点间的服务调用和信息共享实现管理任务的协作.     

Using P2P overlays to provide QoS in service-oriented wireless networks - [Service-oriented broadband wireless network architecture]

An increasing number of applications require some form of guarantees from the network, in terms of bandwidth or access and transfer delay. This demand for quality of service can be met by means of different mechanisms, depending on the networks being traversed, as well as the degree of integration of the services with the communication infrastructure. Whereas end-to-end QoS provision is still an open problem, several possibilities now exist in local environments. The article investigates the capabilities offered by a P2P overlay for distributed bandwidth management in a controlled ad hoc deployment, to support specific requirements in service-oriented wireless networks. The mechanism proposed allows complementing the core functionalities of the IEEE 802.11e protocol, and enhancing them to handle local mobility and dynamic requests for bandwidth. The performance evaluation is provided in an emulated environment to show the effectiveness of the presented approach.     

Reconfigurable and scalable architecture of a system for digital processing of broadband radar signals

A reconfigurable and scalable architecture of systems for digital processing and synthesis of broadband radar signals is studied. The design of a radar with this architecture and a bandwidth of the synthesized and processed signals of 1.5 GHz is considered. The potential to adjust the radar parameters independently on the basis of the system-level analysis of the architecture and by working over the issues of its implementation is demonstrated. The architecture relies on specialized methods for digital signal processing with programmable logic and parallel processing.     

Query routing mismatch alleviation architecture for P2P file lookup in MANETs

A cross-layer optimized query routing mismatch alleviation(QRMA)architecture is proposed to mitigate the problem of query routing mismatch(QRM)phenomenon between the structured peer to peer(P2P)overlay and the routing layer in mobile Ad-hoc networks(MANETs),which is an important issue that results in the inefficiency of lookup process in the system.Explicated with the representative Chord protocol,the proposal exploits the information of topologic neighbors in the routing layer of MANETs to find if there is any optimized alternative next hop in P2P overlay during conventional lookup progress.Once an alternative next hop is detected,it will take the shortcut to accelerate the query procedure and therefore alleviate the QRM problem in scalable MANETs without any assistance of affiliation equipments such as GPS device.The probability of finding out such an alternative node is formulated and the factors that could increase the chance are discussed.The simulation results show that the proposed architecture can effectively alleviate the QRM problem and significantly improve the system performance compared with the conventional mechanism.     

Efficient P2P-based mutual authentication protocol for RFID system security of EPC network using asymmetric encryption algorithm

Internet of Things (IoT) is a new vision of the future technological ubiquity in ubiquitous computing, which becomes the mapping from the real world to the digital one. Radio frequency identification (RFID) technology is a key enabler of the future IoT and it has a great economical potential. However, the RFID system uses of Electronic Product Code (EPC) tags can drastically threaten the security of applications. With the widespread use of RFID technology, its security problems become the hot topic in the academic and industrial fields. Aiming at the RFID network's security problems, we propose a novel P2P based RFID network architecture (P2P-RFID), and analyze the security problems in this kind of network. And a feasible and scalable protocol to guarantee P2P-RFID network security is also presented in this paper. The proposed protocol uses P2P storage technology together with the utilizing of asymmetric encryption algorithm (RSA) based authentication. An analysis proves that the presented protocol is secure. Moreover, the protocol authentication does not require a Certificate Authentication (CA) database, which avoids the single-point bottleneck.     

An economic feasibility study for a broadband virtual pathSONET/ATM self-healing ring architecture

A ring architecture that uses the asynchronous transfer mode (ATM) virtual path (VP) concept to reduce the SONET ring cost in terms of bandwidth management is discussed. The add-drop multiplexer (ADM) proposed for VP ring architectures can evolve from existing SONET ADMs by replacing the STS-3 termination cards by the ATM STS-3c line cards. Existing standard self-healing schemes and protocol SONET rings can be applied to proposed ATM/SONET VP rings. A case study based on a BCC (Bellcore client company) ring network and the sensitivity analysis suggests that the proposed ATM VP ring architecture may be a cost-effective option for implementing the distributed ring grooming system at the DS 1 level. The proposed VP self-healing rings are not only used to carry existing DS 1 and DS 3 service, but can also be used to more cost-effectively consolidate switches for public-switched services and for SMDS, frame relay, and FDDI in metropolitan areas     

Deploying P2P networks for large-scale live video-streaming service [Peer-to-Peer Multimedia Streaming]

Peer-to-peer (P2P) networks have been adopted for Internet live video-streaming service, and several practical systems have been deployed in past years due to the inherent scalability and ease of deployment. However, most of these systems are commercial and proprietary, and hence little research was done in the area of characterizing practical system performance properties. In this article, we mainly present our experience on a practical P2P-based live video- streaming system called GridMedia, which was employed to broadcast live the Chinese Spring Festival Gala show over the Internet. Benefiting from two sets of flush-crowd traces with about 15,239 and 224,453 concurrent users in a 300 kb/s streaming session in 2005 and 2006, we perform a trace study to understand the service capacity, quality of streaming service, connection heterogeneity, user geographic distribution, and request and online duration characteristics. Our observations shed light on those systems and further improvements in the arena of large-scale live video-streaming service over the Internet.     

BRAIN—an architecture for a broadband radio access network of the next generation

The tremendous growth rates of the Internet as well as the area of mobile communications give rise to the chance that the mobile Internet is most promising by combining both the Internet and mobile communications. These prospects are the motivation for the European research project BRAIN (Broadband Radio Access for IP‐based Networks), which is developing an open architecture for a broadband wireless mobile access network offering an integrated communication platform across heterogeneous networks and, thus, goes beyond current third generation systems and towards the mobile Internet. The project covers three major technical areas: support of seamless service provision in a mobile environment; the design of an IP‐based access network that will support non‐cellular technologies such as wireless LANs; and requirements of a broadband air interface suitable for hot spots. BRAIN is going to integrate HIPERLAN/2 with UMTS by means of an IP access network. The work is guided by a user‐centric top‐down approach ensuring that user functionality is the key driver of the project. This article will focus on that part of the BRAIN work which specifies the main interfaces of the BRAIN architecture and deals with aspects related to the support of Quality of Service and mobility. Copyright © 2001 John Wiley & Sons, Ltd.     

海上无线宽带网络架构研究现状及相关技术展望

近年来,国家智慧海洋战略的实施对海上无线通信网络全方位覆盖、海上应急管理水平和信息服务能力等提出更高的要求。从部署海上无线宽带网络的实际需求出发,总结了海上无线宽带网络架构的国内外研究现状,概括了海上无线宽带技术的特点,最后展望了海上无线宽带网络技术的研究前景。在广阔的海洋上部署高速低成本的无线宽带网络定会为海洋产业的发展提供有力的通信保障和技术支持。     

Hybrid wireless-broadband over power lines: a promising broadband solution in rural areas

In rural areas, due to the low population density and the poor familiarization with new technologies, new projects related to broadband access are less profitable. In this article a hybrid wirelessbroadband over power lines network, suitable for rural and remote areas is presented, offering smart grid applications and broadband access along a 107 km medium voltage power grid in Larissa, a rural area in central Greece. This hybrid solution exploits the ubiquitous presence of the power grid along with the adaptability and accessibility of wireless technology. Through the design and implementation of this hybrid network many aspects of BPL technology were successfully dealt with demonstrating that, in addition to enhancing the power grid performance, W-BPL technology may be considered as an alternative broadband solution in rural and/or sparsely populated areas.     

Cloud-P2P云存储结构的模型建立与性能分析

基于Cloud-P2P云存储结构,针对云中心和P2P节点存储层数据副本的访问机制,考虑节点存储层数据副本的修复过程,建立一个三维连续时间Markov链模型。使用矩阵几何解方法导出该模型的稳态解,并给出节点存储层传输率,数据访问延迟和副本修复率等系统性能指标的表达式。通过数值实验和系统仿真定量刻画数据副本数等系统参数对Cloud-P2P云存储结构性能的影响。构造利润函数,进行用户存储层副本数的优化设置。