A systematic framework for unearthing the missing links: measurements and impact

  • Authors:
  • Yihua He;Georgos Siganos;Michalis Faloutsos;Srikanth Krishnamurthy

  • Affiliations:
  • University of California, Riverside;University of California, Riverside;University of California, Riverside;University of California, Riverside

  • Venue:
  • NSDI'07 Proceedings of the 4th USENIX conference on Networked systems design & implementation
  • Year:
  • 2007

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The lack of an accurate representation of the Internet topology at the Autonomous System (AS) level is a limiting factor in the design, simulation, and modeling efforts in inter-domain routing protocols. In this paper, we design and implement a framework for identifying AS links that are missing from the commonly-used Internet topology snapshots. We apply our framework and show that the new links that we find change the current Internet topology model in a non-trivial way. First, in more detail, our framework provides a large-scale comprehensive synthesis of the available sources of information. We cross-validate and compare BGP routing tables, Internet Routing Registries, and traceroute data, while we extract significant newinformation from the less-studied Internet Exchange Points (IXPs). We identify 40% more edges and approximately 300% more peer-to-peer edges compared to commonly used data sets. Second, we identify properties of the new edges and quantify their effects on important topological properties. Given the new peer-to-peer edges, we find that for some ASes more than 50% of their paths stop going through their ISP providers assuming policy-aware routing. A surprising observation is that the degree of a node may be a poor indicator of which ASes it will peer with: the two degrees differ by a factor of four or more in 50% of the peer-to-peer links. Finally, we attempt to estimate the number of edges we may still be missing.