<title>Inferring AS-level Internet topology from router-level path traces</title>

Abstract

A number of recent studies characterize AS-level topology of the Internet by exploiting connectivity information contained in BGP routing tables. In this paper, we present an alternative method for discovering AS connectivity by inferring individual AS connections from the Internet's router-level topology. This methodology has several advantages over using BGP routing tables. First, it allows us to obtain AS-level connectivity information at a finer granularity (e.g., multiple connections between a pair of ASs); second, we can discover ASs aggregated in BGP routing tables; and third, we can identify AS border routers, which may allow us to further characterize inter-AS connections. Since border routers have, by definition, multiple interfaces, each with an address in a potentially different AS, a major challenge of our approach is to properly map border routers to their corresponding ASs. To this end, we present in this paper several mapping rules and heuristics for inferring the ASs of border routers and report on results showing the effectiveness and validity of these rules and heuristics.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.