一种基于层次化兴趣的非结构化P2P拓扑形成模型

A Layered Interest Based Topology Organizing Model for Unstructured P2P

在非结构化P2P系统中有两个根本性的问题需要研究:拓扑的自动生成和查询算法.其中前者更为重要:虽然查询算法通常是独立于拓扑结构的,但一个结构良好的拓扑会极大地改善查询算法的性能.提出一种基于层次化兴趣表达的拓扑生成模型(self adaptive community-based model,简称SACM).在这种模型里,每个节点由自身的资源整体类型倾向决定自己的兴趣(interest),并且采用树形结构来表达兴趣;然后节点由兴趣产生一个二进制序列的CID(community ID),CID将成为拓扑形成的主要依据——具有相近CID的节点能聚集成一个连通性较高的子图(社区).SACM不仅提供了生成聚类拓扑的算法,更为重要的是,它通过兴趣的定义及维护从统计上在资源和网络拓扑之间建立了联系.是否存在这种联系正是结构化P2P于非结构化P2P的本质区别.

There are two pivotal problems in unstructured P2P system： Topology self-organization and query algorithms, however, the former is more important because a well-organized topology can dramatically improve the performance of query algorithms. This paper develops a new mechanism to organize topology based on a hierarchical representation of interest--SACM （self adaptive community-based model）. In this model, each node forms an interest which is dendriform from all resources it possesses. Then a bit sequence CID （community ID） is determined by the interest, and CID is the main metric to organize topology--nodes with the close CID will form a community which is a dense subgraph. SACM not only provides a mechanism to organize topology but also constructs the relationship between resources and topology which is the essential difference between structured and unstructured P2P.