Gnutella环境下资源定位方法的改进

本文在已有研究的基础上提出了一种基于节点间部分通路的资源定位方法,加入节点基于邻居节点的逻辑度选择要建立链接的节点,请求节点通过所构建的逻辑结构来定位资源。仿真实验的结果表明,与传统广播方法相比,所提出的方法能有效地降低Gnutella网络的通讯负载,减少冗余消息,提高Gnutella网络的可扩展性,这些对于未来智能网络打印机的研发具有深远意义。     

利用Gnutella网络的拓扑特性改进其可扩展性

分布式P2P网络Gnutella模型拓扑节点的分布不仅呈现典型的“幂规律”(PowerLaw),而且还具有明显的“小群体”(SmallWorld)特征。但是其对等机共享信息查询的搜索、定位路由协议仅使用“洪泛”算法,因此存在可扩展性问题。论文针对Gnutella网络拓扑节点具有的这些分布特性,提出了一种充分利用这些特性,基于“最大聚集度优先”的查询包路由改进策略,经模拟分析其协议的性能后证明,该策略能有效地提高Gnutella网络的可扩展性。     

基于Gnutella动态拓扑调整的搜索策略

本文介绍了非结构化对等网络Gnutella搜索机制的工作原理,在分析其存在可扩展性问题的基础上,提出一种基于动态拓扑调整的改进策略.仿真实验表明,该策略能够有效降低网络资源的消耗,优化节点间的负载均衡,从而提高网络的可扩展性和资源搜索效率.     

基于主动网络的分布式P2P网络模型

分布式P2P网络Gnutella模型的对等机共享信息查询的搜索、定位路由协议仅使用"洪泛"算法,因此存在可扩展性问题.同时,由于其协议机制仅在应用层实现,缺乏对Intemet底层通信子网路由资源的利用,存在性能与效率不高的问题.为了解决上述问题,考察了Gnutella网络和Internet网络节点的拓扑分布规律,二者不仅均呈现幂规律(power law)和小世界(small world)特征,而且其幂系数t非常近似.提出了一个基于主动网络技术的分布式P2P网络(active distributed pee     

基于Kademlia的P2P网络资源定位模型改进

根据基于分布式散列表(DHT)的P2P网络资源定位方法,将虚拟节点引入结构化P2P系统,在拓扑形成时充分利用网络访问的区域性和物理网络中节点的邻近性来降低访问延迟并优化路由选择。构建一种改进的基于Kademlia的P2P网络资源定位模型,提高了网络可扩展性和可管理性及网络运行效率和资源利用率。仿真结果表明,改进后的模型继承了DHT和Kademlia的优点,在路由选择、查找成功率和平均逻辑路径长度等方面的性能均优于原Kademlia模型。     

基于P2P的网络资源搜索引擎研究

介绍非结构化对等网络在网络资源搜索机制的工作原理,分析其带来的可扩展性同题,详细探讨两个关键技术Caching技术和Gnutella搜索机制,优化节点间的负载均衡,进而提高网络的可扩展性和网络资源搜索效率.     

非结构化对等网络Gnutella搜索机制的改进

本文介绍了非结构化对等网络Gnutella搜索机制的工作原理,分析其带来的可扩展性问题,提出一种动态拓扑调整的改进策略。仿真实验表明,该策略能够有效降低网络资源的消耗,优化节点间的负载均衡,进而提高网络的可扩展性和资源搜索效率。     

基于兴趣子网的Gnutella网络资源定位的研究

从资源定位的准确性、有效性出发,分析了当前一些有关Gnutella网络的主要的资源搜索算法,提出了一种基于兴趣子网的非结构P2P网络资源定位的新算法.该算法借助带权值的路由信息反向植入策略以及引入的引导节点查询策略,有效地避免了网络中出现单点失效的现象,并在保持高速查询、高命中率的同时大大减少了查询信息量和延时,从而提高资源搜索效率,降低网络带宽消耗,减轻网络拥塞.     

P2P网络Gnutella模型中搜索消息的路由机制及改进研究

介绍了分布式P2P网络Gnutella模型的节点定位、查询消息的路由机制,分析了存在的问题。在此基础上,提出了一种基于分布式节点邻居连接信息的对“扩散”路由机制的改进策略,能有效地提高Gnutella网络的可扩展性。     

P2P网络Gnutella 0.6模型研究

在介绍Gnutella 0.6网络模型的体系结构及工作原理的基础上,对新版协议在Gnutella 0.6 网络超级节点、Gnutella一般扩展协议(GGEP)、主机和Pong缓存机制、流量控制等方面的特点进行了分析研究,指出了新版协议在P2P网络可扩展性以及网络安全性方面存在的问题,并对其改进进行了研究.     

SELF-ORGANIZING PEER-TO-PEER SOCIAL NETWORKS

Peer-to-peer (P2P) systems provide a new solution to distributed information and resource sharing because of its outstanding properties in decentralization, dynamics, flexibility, autonomy, and cooperation, summarized as DDFAC in this paper. After a detailed analysis of the current P2P literature, this paper suggests to better exploit peer social relationships and peer autonomy to achieve efficient P2P structure design. Accordingly, this paper proposes Self-organizing peer-to-peer social networks (SoPPSoNs) to self-organize distributed peers in a decentralized way, in which neuron-like agents following extended Hebbian rules found in the brain activity represent peers to discover useful peer connections. The self-organized networks capture social associations of peers in resource sharing, and hence are called P2P social networks. SoPPSoNs have improved search speed and success rate as peer social networks are correctly formed. This has been verified through tests on real data collected from the Gnutella system. Analysis on the Gnutella data has verified that social associations of peers in reality are directed, asymmetric and weighted, validating the design of SoPPSoN. The tests presented in this paper have also evaluated the scalability of SoPPSoN, its performance under varied initial network connectivity and the effects of different learning rules.     

Gnutella网络文件共享属性的测量与分析

以Gnutella网络为测量对象,分析了Gnutella网络的基本特点和关键协议,利用Limewire的源代码设计了一个Gnutella网络内容爬虫,测量了Gnutella网络中用户的共享文件类型、共享文件数目、共享空间、文件副本、用户日均在线时长和节点应用层带宽,并对以上测量结果进行统计分析。统计分析表明文件共享数目与共享空间存在显著的相关关系,应用层带宽与日均在线时长则存在弱相关关系。此外,对Gnutella网络中的用户按照共享文件数目、共享空间、应用层带宽、日均在线时长这4个方面进行了聚类分析,分析结果表明,Gnutella网络中的平庸用户占所统计用户数的97%。     

一种非结构化对等网络短路效应解决方法

非结构化对等网络Gnutella存在短路效应，这会严重影响消息的到达率，造成网络查询效率低下。利用Gnutella网络拓扑的分布呈现典型的幂规律和小世界特性，将少量度很大的节点提升为超级结点，并以超级节点为中心，将兴趣相同或相似的节点进行聚类，从而形成若干自治域小世界，这样Gnutella网络模型被抽象层次化，自治域内查询请求由本域的超级节点直接处理，自治域间查询请求在超级节点间进行转发。研究表明，这种方法可以有效解决短路效应问题。     

P2P网络中基于谣言传播机制的资源搜索算法

当前许多P2P网络如KaZaA和Gnutella模型仅使用“洪泛”广播机制,从而造成严重的通信拥塞。针对这种现状,提出了一种基于谣言传播机制的资源搜索算法,任何运行该算法的源节点只需要相对少的节点参与通信,就能以相对大的概率找到资源。仿真结果表明,该算法是优异的。     

HPC5: An efficient topology generation mechanism for Gnutella networks

In this paper, we propose a completely distributed topology generation mechanism named HPC5 for Gnutella network. A Gnutella topology will be efficient and scalable if it generates less number of redundant queries. This can be achieved if it consists of a fewer number of short length cycles. Based on this principle, our protocol directs each peer to select neighbors in such a way that any cyclic path present in the overlay network will not generate any redundant query. We show that our approach can be deployed into the existing Gnutella network without disturbing any of its parameters. We also show that the probability of inconsistencies arising during topology generation, using our mechanism, which may lead to the formation of a small number of short length cycles is very low. However, we have also proposed an inconsistency handling protocol that detects such short length cycles and effectively removes them. We implemented a Gnutella prototype to compare and validate the efficiency of our protocol over existing Gnutella. Simulation results indicate that our mechanism outperforms existing Gnutella in terms of network coverage (the number of unique peers explored during query propagation in limited flooding) and message complexity. Structural analysis indicates that the proposed enhancement conserves the robustness of existing Gnutella network. Finally, we draw comparisons of the proposed protocol with a state-of-the-art topology optimization protocol named Distributed Cycle Minimization Protocol (DCMP); the simulation results indicate that HPC5 outperforms DCMP in terms of message overhead and network coverage.     

Reducing query overhead through route learning in unstructured peer-to-peer network

In unstructured peer-to-peer networks, such as Gnutella, peers propagate query messages towards the resource holders by flooding them through the network. This is, however, a costly operation since it consumes node and link resources excessively and often unnecessarily. There is no reason, for example, for a peer to receive a query message if the peer has no matching resource or is not on the path to a peer holding a matching resource. In this paper, we present a solution to this problem, which we call Route Learning, aiming to reduce query traffic in unstructured peer-to-peer networks. In Route Learning, peers try to identify the most likely neighbors through which replies can be obtained to submitted queries. In this way, a query is forwarded only to a subset of the neighbors of a peer, or it is dropped if no neighbor, likely to reply, is found. The scheme also has mechanisms to cope with variations in user submitted queries, like changes in the keywords. The scheme can also evaluate the route for a query for which it is not trained. We show through simulation results that when compared to a pure flooding based querying approach, our scheme reduces bandwidth overhead significantly without sacrificing user satisfaction.     

基于资源评价的信任管理模型

针对P2P网络中交易的安全性问题,提出了一种基于资源评价的信任管理模型。首先给出评价节点行为信任的好评度的概念,用模糊综合评判的方法计算节点对交易的单次好评度,每次交易后的交易记录表由提供资源的节点的母节点进行管理和存储;当节点选择提供资源的节点时,不仅考虑对目标节点的直接信任度,还考虑此次交易资源的总好评度,在计算直接信任度时考虑了时效性和交易资源的重要程度两个因素,交易资源的总好评度的计算数据来源于该资源的评价节点给出的以往评价;最后引入了基于虚拟货币的激励机制,以有效地提高节点参与的积极性。仿真实验表明,该模型能有效抵制恶意节点的攻击,提高网络交易的成功率。     

Evolution of superpeer topologies — An analytical perspective

In superpeer based networks, resourceful peers (having high bandwidth and computational resources) are discovered through the process of bootstrapping, whereby they get upgraded to superpeers. However, bootstrapping is influenced by several factors like limitation on the maximum number of connections a peer can have due to bandwidth constraints, limitation on the availability of information of existing peers due to cache size constraints and also by the attachment policy of the newly arriving peers to the resourceful peers. In this paper, we derive closed form equations that model the effect of these factors on superpeer related topological properties of the networks. Based on the model, we show that existing bootstrapping protocols can lead to a situation where only a small fraction of the resourceful peers gets converted to superpeers, i.e., a large fraction of them remain underutilized; we later validate this statement using real Gnutella snapshots. We observe that as a node attachment policy, newly arriving peers must use a combination of random and preferential attachment strategy so as to ensure proper utilization of the resourceful peers. We also show that the cache parameters must also be suitably tuned so as to increase the fraction of superpeers in the network. Finally, we show that in real Gnutella networks the degree distribution generated using our models suitably fits the corresponding empirical values.     

ERSN:一种高效鲁棒的超结点对等网络

超结点对等网络利用对等结点的异构性解决了低带宽结点带宽瓶颈问题,但目前超结点对等网络的构建协议效率低且网络拓扑鲁棒性弱.提出一种高效鲁棒的超结点对等网络ERSN,采用基于漫步算法的结点采样协议,估计网络需求,构建高效的超结点对等网络,并建立叶结点间的应急连接,增强超结点对等网络的鲁棒性.模拟实验证明,与Gnutella0.6超结点对等网络比较,ERSN网络中负责处理定位请求的结点数目最多减少了76%,并在多个超结点和叶结点同时离开网络的情况下,将文件定位命中率最大提高了36.4%.