Humpty Dumpty: Putting iBGP Back Together Again

  • Ashley Flavel
  • Jeremy McMahon
  • Aman Shaikh
  • Matthew Roughan
  • Nigel Bean
Part of the Lecture Notes in Computer Science book series (LNCS, volume 5550)


Humpty Dumpty is the anthropomorphic nursery-rhyme egg broken into many pieces. Similarly, we have many pieces of measurement data to represent the current iBGP state. However, unlike the nursery-rhyme where the King’s men couldn’t put Humpty together again, we present a systematic approach to putting all the pieces of measured iBGP data together to obtain a more complete picture of a network’s routing state.

Our technique determines the decisions made by all routers in a network. It is efficient, has no assumptions about router configuration and is accurate. We present a case-study of a large Tier-2 ISP, finding for those routers with adequate measurement infrastructure, we consistently find the egress location for 99.9999% of (router, prefix) pairs. Further, for the 85% of routers without measurement infrastructure we predict their decisions. This technique has been successfully applied in a ‘what-if’ scenario and has future applications in the real-time analysis of routing decisions.


iBGP Route prediction 


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Copyright information

© IFIP International Federation for Information Processing 2009

Authors and Affiliations

  • Ashley Flavel
    • 1
  • Jeremy McMahon
    • 2
  • Aman Shaikh
    • 3
  • Matthew Roughan
    • 1
  • Nigel Bean
    • 1
  1. 1.School of Mathematical SciencesUniversity of AdelaideAustralia
  2. 2.TRC Mathematical ModellingUniversity of AdelaideAustralia
  3. 3.AT&T Labs - ResearchUSA

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