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P2P流媒体关键技术研究 总被引:2,自引:2,他引:0
冯健 《微电子学与计算机》2009,26(8)
探讨在Peer节点服务能力的异构性、节点的动态性以及流媒体本身的特殊性下,使P2P流媒体系统保证服务质量的关键技术.从拓扑构建、调度策略、缓存机制三个方面总结P2P流媒体系统涉及的节点选择算法、节点定位方法、数据调度算法、缓存的替换和中继算法等关键技术,分析其存在的问题,指出P2P流媒体关键技术的未来研究方向,对P2P流媒体系统的研究和开发具有重要意义. 相似文献
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个人计算机性能的提高和网络带宽的增加使得P2P流媒体应用系统迅速发展,本文对P2P流媒体系统模型和最大数据传输速率进行研究.提出一种P2P流媒体系统稳定状态下的系统模型,该模型使用较少的参数刻画系统在稳定状态下的属性.推导证明系统在稳定状态下支持的最大数据传输速率,并提出一种集中式算法WFSOT,快速构造支持最大数据传输速率的节点拓扑结构及分配节点带宽.对WFSOT算法进行分析,重点讨论节点在拓扑结构中深度的变化. 相似文献
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针对P2P流媒体网络中的节点选择问题,将移动代理引入P2P网络,建立起用于有效实现P2P网络节点的市场化节点选择模型.基于该模型,进一步提出了一种基于市场机制的自适应节点选择算法MANS:通过模拟市场经济中的价格机制适时调整节点的带宽价格,并动态划分节点角色,依据所建立的评价模型选择最优节点,进行数据服务.最后将该模型与MANS算法运用于直播场景,对仿真结果进行了分析并和静态选择算法进行了比较. 相似文献
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提出一种在对等互联网络技术(P2P)流媒体系统中引入内容分发网络(CDN)的管理机制,整合并利用用户剩余带宽资源的设计.从P2P流媒体系统中选取高性能、高带宽、在线时间稳定的节点作为CDN边缘服务器,在智能化的调度下为非P2P用户包括手机用户提供C/S模式流媒体服务.使部分用户可以直接通过标准控件接入.通过详细的性能分析阐明了该系统的优势,并具体讨论了该设计在实现过程中关于控件选择、节点选取、负载平衡算法等细节问题.通过实际测试与调查证明,该设计在未来流媒体业务,特别是手机流媒体业务中有较好的应用前景. 相似文献
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随着互联网的迅速发展,远程网络教育已经逐渐普及。然而已有的网络技术不支持动态多媒体数据和实时流数据,且存在着流媒体技术中服务器的承载问题。针对这些问题设计基于P2P流媒体技术的网络教育系统,其中每个网络节点既是服务的消费者又是服务的提供者,针对Web服务模式,有效地解决了流媒体系统中存在的问题,同时具有对网络带宽和服务器处理能力要求低、易部署和易扩展的特点。 相似文献
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随着计算机处理能力的不断增强,特别是网络技术的迅速发展,不同主机之间的资源共享问题成为研究的热点.对等网络(Peer-to-Peer,简称P2P)作为一种完全分布的计算模型,可以脱离中央服务器实现对等节点间的直接通信,从而充分利用每个网络节点自身的资源,实现整个网络计算资源的充分利用和信息资源的高效共享.在对等网络的众多研究领域中,关于查找算法的研究具有核心地位.本文对现有对等网络查找算法中的以Chord为代表的结构化分布式查找算法,然后在Chord数学模型的基础上,提出了Chord查找算法的改进方法. 相似文献
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本文基于当前P2P流媒体系统激励机制的研究与应用成果,分析并归类应用于P2P流媒体系统的典型的激励机制:基于直接互惠、基于信誉、基于货币交易和基于社会财富再分配的激励机制。对比分析不同激励机制的协作程度、公平性、对能力不同节点的影响,同时结合各机制目前存在的问题提出进一步的研究方向。 相似文献
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Seyedakbar Mostafavi Mehdi Dehghan 《International Journal of Communication Systems》2016,29(6):1057-1072
Video traffic offloading through the helper peers can significantly alleviate the server workload and enhance users' quality of experience. In this paper, the complex interactions of a number of helpers seeking to trade their bandwidth surplus in a peer‐to‐peer market are studied using non‐cooperative game theory and double auction. In particular, a non‐cooperative game is formulated among the helpers in which each helper can make a decision on the maximum amount of upload bandwidth surplus that it is willing to sell so as to maximize its utility function that reflects the tradeoff between the benefits from bandwidth sharing and its associated costs. Then, the price governing the bandwidth trading market between the helpers and peers is determined via a truthful double auction mechanism. To solve the game, an algorithm based on the best response dynamics is proposed using which helpers can reach a Nash equilibrium point. Simulation results exhibit that the proposed algorithm achieves significant performance improvements in terms of utility per selling helpers. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Stefano Asioli Naeem Ramzan Ebroul Izquierdo 《Signal Processing: Image Communication》2012,27(5):513-521
In this paper we describe a game theoretic framework for scalable video streaming over a peer-to-peer network. The proposed system integrates minimum delay functionalities with an incentive provision mechanism for optimal resource allocation. First of all, we introduce an algorithm for packet scheduling that allows users to download a specific sub-set of the original scalable bit-stream, depending on the current network conditions. Furthermore, we present an algorithm that aims both at identifying free-riders and minimising the transmission delay. Uncooperative peers are cut out of this system, while users upload more data to those which have less to share, in order to fully exploit the resources of all peers. Experimental evaluation shows that the proposed model can effectively cope with free-riders and minimise the transmission delay for scalable video transmission by exploiting a packet scheduling algorithm, game theory, and a minimum-delay algorithm. 相似文献
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基于对等网(P2P)技术的视频流媒体系统以其较低的服务器开销和良好的可扩展性被广泛应用。但由于在这类系统中普遍存在节点的资源及视频播放位置的异构性,使得节点负载不均衡的问题极易发生,进而严重影响到节点的视频播放质量。该文重点研究面向节点负载均衡的节点带宽请求分配策略,将服务请求节点竞争服务提供节点带宽的行为建模为一个非协作博弈,通过寻求该博弈问题的Nash均衡解的方法确定优化的带宽请求分配(GBRA)策略。通过和典型的带宽请求分配策略进行实验对比,数值结果表明该文提出的GBRA 策略能有效改善P2P流媒体网络节点负载不均的问题并降低节点获取所需视频数据的平均延迟。
相似文献15.
P2P网络中的自组织管理模式使得节点的自私行为大量存在.建立相应解决方案所面临的主要问题是难以继续维持P2P网络拥有的自组织及规模可扩放性等特性.目前存在的信用管理模型或者激励模型多是采用泛洪方式获得网络其他节点的历史行为信息,庞大的报文通信量和推导算法的高时间复杂度制约了所能应用的P2P网络的规模.本文提出了一种利用随机相遇博弈理论指导建立的P2P资源共享网络激励模型ResP2P.该模型通过引入节点信誉及信誉恢复区分机制,同时制定相关行为社会规范,来激励理性节点为使其自身收益最大化而向整个网络贡献资源,并且ResP2P所对应的分布式算法易于在自组织管理模式的网络环境中实施.实验证实了ResP2P模型激励机制的有效性. 相似文献
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针对数据中心链路上存在时间窗不重叠的空闲带宽的情况,提出了利用该带宽分发容迟数据的基本思路,进而设计了一种分布式可扩展的空闲带宽感知的节点选择算法LBAPS,该算法避免了集中优化,适合目标节点较多的情况。为了匹配最优的带宽空闲节点,LBAPS按综合度量进行节点选择;为了优先把文件块上传到空闲带宽大的节点以及尽早把不同的块分布到更多节点,LBAPS按阈值预留资源以及按时间片退出上传。基于LBAPS实现了内容云原型系统P2PStitcher。PlanetLab上的实验表明,LBAPS算法所提出的策略可以有效地减少平均分发时间。 相似文献
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从虚拟网络的角度考虑虚拟网络对底层资源的选择问题,将虚拟网络对底层网络中物理路径的自主选择抽象成一个演化博弈,虚拟网络通过反复博弈学习来调整物理路径的选择。利用模仿者动态方程分析博弈中不同策略的比例动态变化,证明了模仿者动态是底层资源动态选择博弈的合理策略更新机制。应用势博弈理论分析了博弈的演化过程,证明了演化的结果会达到演化平衡,确保了每个虚拟网络都获得了最优策略选择。最后基于模仿者动态策略选择机制提出了一个演化算法,通过数值仿真模拟了不同初始策略分布下虚拟网络对底层网络路径的选择过程,实验结果表明演化博弈收敛到了稳定点,仿真结果与理论分析的结果相吻合。 相似文献
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MA Xin-Xin ZHAO Yang QIN Zhi-Guang 《中国电子科技》2007,5(1):18-22,28
In unstructured peer-to-peer (P2P) systems such as Gnutella, a general routing search algorithm is used to blindly flood a query through network among peers. But unfortunately, malicious nodes could easily make use of the search approach launching distributed denial of service (DDoS) attack which aims at the whole network. In order to alleviate or minimize the bad effect due to behavior of malicious nodes using the flooding search mechanism, the paper proposes a Markov-based evaluation model which exerts the trust and reputation mechanism to computing the level of trustworthy of nodes having the information requested by evaluation of the nodes' history behavior. Moreover, it can differentiate malicious nodes as early as possible for isolating and controlling the ones' message transmitted. The simulation results of the algorithm proposed show that it could effectively isolate malicious nodes, and hold back the transmission of vicious messages so that it could enhance tolerance of DDoS based on flooding in Guutella-like P2P network. 相似文献
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Access control mechanism using flexible multi‐layer structure for mesh‐based P2P live streaming systems
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Chuan‐Ching Sue Kai‐Chun Chuang Chi‐Yu Hsu 《International Journal of Communication Systems》2016,29(11):1740-1760
When thousands of new peers seek to join the peer‐to‐peer (P2P) system within a very short time (i.e., the so‐called flash crowd event), most of the peers suffer a long startup delay as a result of peer over‐competition. Accordingly, recent studies have proposed a slot‐based user access control (UAC) mechanism, which periodically admits a certain number of new peers to the system, and a user batch join (UBJ) mechanism, which preconstructs the new peers into a fixed‐size tree structure before peer join process. However, in the UAC mechanism, it is difficult to determine the optimal time slot length; while in the UBJ mechanism, it is difficult to determine the optimal tree size. Accordingly, the present study proposes a structured access control (SAC) mechanism, in which the new‐arriving peers are preconstructed to a flexible multilayer structure to overcome the limitation of a fixed‐size tree structure, and the number of peers in each layer of the structure is determined based on a consideration of the remaining upload bandwidth of the P2P system. Based on the assumption of a heterogeneous upload bandwidth capability of the peers, an analytical model is derived to describe the growth behavior of a P2P system with access control. It is shown that the simulation results for the growth rate of a P2P system based on the SAC mechanism are in good agreement with those obtained from the analytical model. In addition, the simulation results show that the SAC mechanism outperforms the UAC and UBJ mechanisms in terms of a more rapid system growth and a shorter average startup delay. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献