Ratul Mahajan,
David Wetherall, and Thomas Anderson.
Understanding BGP Misconfiguration. Proceedings of the
2002 ACM SIGCOMM Conference, pages 3 - 16, August 2002.
Abstract:
It is well-known that simple, accidental BGP
configuration errors can disrupt Internet connectivity. Yet little is known
about the frequency of misconfiguration or its causes, except for the few
spectacular incidents of widespread outages. In this paper, we present the first
quantitative study of BGP misconfiguration. Over a three week period, we
analyzed routing table advertisements from 23 vantage points across the Internet
backbone to detect incidents of misconfiguration. For each incident we polled
the ISP operators involved to verify whether it was a misconfiguration, and to
learn the cause of the incident. We also actively probed the Internet to
determine the impact of misconfiguration on connectivity. Surprisingly, we
find that configuration errors are pervasive, with 200-1200 prefixes (0.2-1.0%
of the BGP table size) suffering from misconfiguration each day. Close to 3 in 4
of all new prefix advertisements were results of misconfiguration. Fortunately,
the connectivity seen by end users is surprisingly robust to misconfigurations.
While misconfigurations can substantially increase the update load on routers,
only one in twenty five affects connectivity. While the causes of
misconfiguration are diverse, we argue that most could be prevented through
better router design.