中文摘要：

对Internet AS级拓扑的社团结构进行了分析，发现其模块度在0．38和0．48之间，表明Internet拓扑具有一定的模块特性。社团分解结果表明，处于同一社团内的AS许多都是相同或邻近国家的AS，表明了地理因素是Internet社团结构形成的一个重要原因。对Internet国家级拓扑的社团结构的分析，更明显地表明了地理因素对Internet互联所产生的影响。PFP模型所生成的网络的模块度仅有0．30左右，与真实Internet有一定差距，因此提出了一种考虑了地理因素的Internet模型——GeoPFP模型，在包括小度值节点聚类特性等诸多性质上，新模型都能准确模拟Internet，同时新模型的模块度在0．42附近，与真实Internet一致。

英文摘要：

The community property of Internet AS-Level topology is investigated in this paper, and we found that the topology has a modularity between 0. 38 and 0.48, which means that Internet is a network with significantly community structure. The decomposition result reveals that most ASes in the same com-interconnections of Internet. al Internet. So a new Interne The new model can simulate gree nodes, and it has modu The modulari t Model with most netw larity arou ty of PFP model is only geographical considerat around 0.30, smaller than that of actual Internet.So a new Internet Model with geographical consideration is proposed,named GeoPFP model.The new model can simulate most network properties of Internet,including cluster coefficient of small degree nodes,and it has modularity around0.42,in conformity with the reality.