Abstract: In order to study and understand thoroughly the distribution law of the node degree of the Internet topology at autonomous system level，a new power-law model for the topology of the Internet Autonomous System（AS） is proposed.The relations between the fraction of the richest nodes and the fraction of those degrees in the hands of the richest ones of the Internet AS topology are derived based on this topology model，and the influence of the topology parameters，such as the exponent of the power-law and the maximum node degree，on the above-mentioned relations is researched.The theoretical and numerical results show that the top 27% best-connected nodes of the topology at the Internet AS level hold about 73% degrees（this is the“73/27”law），and the empirical analysis demonstrates that the power-law model for the Internet AS topology is effective and there is the“73/27” law of the Internet topology at AS level.

Key words: Internet autonomous system, power-law model, “73/27” law, richest nodes

摘要： 为了深入理解和认清Internet AS拓扑中节点度的分配规律，提出适合Internet AS拓扑的幂律模型，利用该模型推导Internet AS拓扑中最富有节点数占网络总节点数的比例与这些最富有节点所拥有的节点度数占网络节点总度数的比例之间的关系，分析研究幂律指数和最大节点度等拓扑参数对该比例关系的影响，通过数值分析发现Internet AS拓扑中27%的最富有节点拥有约73%的节点度数（简称为“73/27”规律），基于Internet AS拓扑经验数据对上述结果进行验证分析，结果表明该幂律模型对Internet AS拓扑是有效的，Internet AS拓扑存在“73/27”规律。

关键词: Internet 自治系统, 幂律模型, “73/27”规律, 最富有节点