Ethan Katz-Bassett, University of Washington

Location :

LIP6 - Room 550

Abstract :

Traceroute is the most widely used Internet diagnostic tool today.  Network
operators use it to help identify routing failures, path inflation, and router
misconfigurations.  Researchers use it to map the Internet, predict
performance, geolocate routers, and classify the performance of ISPs.
However, traceroute has long had a fundamental limitation that affects all
these applications: it does not provide reverse path information.  Although
various public traceroute servers across the Internet provide some visibility,
no general method exists for determining a reverse path from an arbitrary
destination, without control of that destination.

In this talk, we address this longstanding limitation by building a
reverse traceroute tool.  Our tool provides the same information as traceroute, but for
the reverse path, and it works in the same case as traceroute, when the user
may lack control of the destination.  Our approach combines a number of ideas:
source spoofing, IP timestamp and record route options, and multiple vantage
points.  We deploy our system on PlanetLab and compare reverse traceroute paths with
traceroutes issued from the destinations.
In the median case our tool finds 87% of the
hops seen in a directly measured traceroute along the same path.  We then use our
reverse traceroute system to study previously unmeasurable aspects of the Internet: we
uncover more than a thousand peer-to-peer AS links invisible to current topology
mapping efforts, and we present a case study of how a content provider could
use our tool to troubleshoot poor path performance.

Host :

LIP6