中文摘要：

本文基于AS路径符合＂无谷模型＂这一公认的假设推导理论上的测量结果,并与实际数据进行比较.发现对于超过90%的测量点,其P-P边的实际测量结果只有理论上的30%.本文分析了被测AS的拓扑特征与其拓扑被发现完整性之间的关系,发现测量完整性随着被测AS与测量点间距离、测量点和被测AS邻居数量的增大而减少,与测量点的路由策略没有明显关系.

英文摘要：

We formally prove the range limit of topology observed by a BGP monitor based on the ＂valley free＂ model. By comparing with the actual BGP data, we found that for more than 90% of monitors,the observed P-P links are less than 30% of its range limit. By analyzing the relationships between the characteristics of observed ASes and the completeness of observed topology for those ASes, we found that the completeness of the topology is impacted by the distance to the BGP monitor, its adjacency, and other factors.