Where the Sidewalk Ends: Extending theInternet AS Graph Using Traceroutesfrom P2P Users

An accurate Internet topology graph is important in many areas of networking, from understanding ISP business relationships to diagnosing network anomalies. Most Internet mapping efforts have derived the network structure, at the level of interconnected autonomous systems (ASes), from a rather limited set of vantage points. In this paper, we argue that a promising approach to revealing the hidden areas of the Internet topology is through active measurement from an observation platform that scales with the growing Internet. By leveraging measurements performed by an extension to a popular P2P system, we show that this approach indeed exposes significant new topological information. Our study is based on traceroute measurements from more than 992,000 IPs in over 3,700 ASes distributed across the Internet hierarchy, many in regions of the Internet not covered by publicly available path information. To address this issue we develop heuristics that identify 23,914 new AS links not visible in the publicly-available BGP data—12.86 percent more customer-provider links and 40.99 percent more peering links, than previously reported. We validate our heuristics using data from a tier-1 ISP, and show that they successfully filter out all false links introduced by public IP-to-AS mapping. We analyze properties of the Internet graph that includes these new links and characterize why they are missing. Finally, we have made the identified set of links and their inferred relationships publicly available.