基于节点簇的非结构化P2P搜索策略

以Gnutella为代表的非结构化P2P系统通常会呈现复杂网络结构，针对其度分布服从幂律分布的特点，提出一种基于节点簇的搜索策略。该策略利用节点簇来存储系统中文件的索引，通过将搜索过程限制于节点簇内部来提高搜索性能。然后，基于数学模型的理论分析给出了搜索性能上下界的数学描述。实验结果表明，搜索性能与簇的阈值c密切相关；c的取值范围灵活性很大，此时稀有文件的搜索效率至少可以提高一倍以上，文件索引的传输和存储代价可以减少一个数量级。该策略不需要学习全局拓扑知识，具有稳定并且易于实现和部署的优点。

Cluster-Based Search in Unstructured Peer-to-Peer Network

Most of the unstructured peer-to-peer applications exhibit a characteristic of complex networks. We are motivated by this fact and propose a novel cluster-based search strategy. The cluster is used for storing the file indices. The search process is constrained between the nodes at the cluster to improve the search performance. The analysis results based on mathematic model give the formulas of search performance, and experiment results certificate the search performance is closely related to the cluster threshold c. The search strategy improves the search effectiveness by 100% at least and decreases the transferring and storing cost by roughly an order of magnitude. The search strategy is stable, and can be realized and deployed easily with no need for global topology knowledge.