【作者】 任平凡；

【导师】 黄东军；

【作者基本信息】 中南大学 ， 计算机应用技术， 2009， 硕士

【摘要】 近年来,P2P技术成为了计算机界研究的热点,而P2P覆盖网络作为P2P系统的骨架,对其系统性能有着至关重要的影响。现有的P2P覆盖网络可分为非结构化和结构化两类,非结构化网络具有大簇系数和大平均网络距离的特性,而在结构化网络中,簇系数和平均网络距离均较小。同时,在现有的P2P网络构建中,下层的网络拓扑结构并没有得到考虑,因此在端到端的通信中,尽管覆盖网上所反映出路径跳数很少,但实际的延迟可能会很大。首先,针对P2P覆盖网络目前存在的问题,本文结合小世界理论和底层拓扑信息探测的思想提出了一种网络敏感的结构化小世界P2P覆盖网络(NSWO网络)模型,并对该覆盖网络的构建算法做了详细描述,该网络同时具有网络敏感和小世界网络大簇系数小平均网络距离的特性。然后,我们利用上述特性在所提出的NSWO网络的基础上构建了一种有效的资源搜索算法,该算法采用先簇内搜索,再簇间搜索的原则,通过仿真实验与现有的经典P2P覆盖网络资源搜索算法比较,验证了该算法在平均网络延迟和平均搜索路径长度上均有优势。最后,我们同样是利用NSWO网络的特性,提出了一个NSWO网络上的拥塞控制算法,以解决网络中由于热点资源的出现而引发的网络突然拥塞问题,实验表明,该算法具有较好的拥塞控制能力。更多还原

【Abstract】 In recent years, P2P technology has become the hot spot in computer research. And the P2P overlay network, as P2P system’s skeleton, has played a very important role in the P2P system’s performance. The existing P2P overlay network can be divided into two types of unstructured one and structured one. The unstructured overlay network has characteristics of big cluster coefficient and great average network distance. And in structured overlay network, the cluster coefficient and average network distance are both small. At the same time, in the existing P2P network construction, the underlying network topology hasn’t been taken into account. Thus, in peer-to-peer correspondence, the actual latency can actually be very large although the hops of path are just few.First, in view of existing problems of P2P overlay network, this article applies the small world theory and the idea of network topology information collection to propose a new P2P overlay network (NSWO network).and this new overlay network’s construction algorithm has been given a detailed description in the paper. This overlay network has all Characteristics of network-aware, big cluster coefficient and small average network distance.Then, taking advantage of NSWO network’s characteristics, we have developed a highly efficient algorithm for object searching. This algorithm is designed with principle that it first searches in cluster, and then searches between clusters. Through the simulation experiments, it has been confirmed that, comparing with the existing classic P2P overlay network, our algorithm has superiority in average network latency and average searching path’s length.Finally, we have also used NSWO network’s characteristics to propose a set of algorithm for congestion control, in order to handle the flash crowd caused by popular object’s appearance in network. The simulation experiments have indicated that this algorithm has a good congestion control ability.更多还原