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Summary: Measuring ISP Topologies with Rocketfuel
Neil Spring Ratul Mahajan David Wetherall
{nspring,ratul,djw}@cs.washington.edu Computer Science and Engineering
University of Washington
Seattle, WA 981952350
ABSTRACT
To date, realistic ISP topologies have not been accessible to the re
search community, leaving work that depends on topology on an
uncertain footing. In this paper, we present new Internet mapping
techniques that have enabled us to directly measure routerlevel ISP
topologies. Our techniques reduce the number of required traces
compared to a bruteforce, alltoall approach by three orders of
magnitude without a significant loss in accuracy. They include the
use of BGP routing tables to focus the measurements, exploiting
properties of IP routing to eliminate redundant measurements, bet
ter alias resolution, and the use of DNS to divide each map into
POPs and backbone. We collect maps from ten diverse ISPs using
our techniques, and find that our maps are substantially more com
plete than those of earlier Internet mapping efforts. We also report
on properties of these maps, including the size of POPs, distribu
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