Towards capturing representative AS-level Internet topologies

  • Authors:
  • Hyunseok Chang;Ramesh Govindan;Sugih Jamin;Scott J. Shenker;Walter Willinger

  • Affiliations:
  • Department of EECS, University of Michigan, 1301 Beal Ave., Ann Arbor, MI;Department of CS, University of Southern California, Los Angeles, CA;Department of EECS, University of Michigan, 1301 Beal Ave., Ann Arbor, MI;ICSI, 1947 Center St., Suite 600, Berkeley, CA;AT&T Labs-Research, 180 Park Ave., Florham Park, NJ

  • Venue:
  • Computer Networks: The International Journal of Computer and Telecommunications Networking
  • Year:
  • 2004

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Recent studies on AS-level Internet connectivity have attracted considerable attention. These studies exclusively relied on BGP data from the Oregon route-views [University of Oregon Route Views Project, http://] to derive some unexpected and intriguing results. The Oregon route-views data sets reflect AS peering relationships, as reported by BGP, seen from a handful of vantage points in the global Internet. The possibility that these data sets may provide only a very sketchy picture of the complete inter-AS connectivity of the Internet has received little scrutiny. By augmenting the Oregon route-views data with BGP summary information from a large number of Internet Looking Glass sites and with routing policy information from Internet Routing Registry (IRR) databases, we find that (1) a significant number of existing AS peering relationships remain hidden from most BGP routing tables, (2) the AS peering relationships with tier-1 ASs are in general more easily observed than those with nontier-1 ASs, and (3) there are at least about 40% more AS peering relationships in the Internet than commonly-used BGP-derived AS maps reveal (but only about 4% more ASs). These findings point out the need for continuously questioning the applicability and completeness of data sets at hand when establishing the generality of any particular Internet-specific observation and for assessing its (in)sensitivity to deficiencies in the measurements.