Supervision : Serge FDIDA

Co-supervision : FRIEDMAN Timur

Reverse-Engineering the internet Routing through joint analysis of BGP and IP-level measurements

Internet is the result of interaction of the thousands of networks that compose it. Each of them is called an autonomous system (AS) and has a unique number (ASN). Routing policies of ASes and business agreements remain in most cases confidential. To understand Internet routing, researchers use routing models. A large family of models represents an AS as an atomic structure. We make in this work three contributions. We look first on a set of commonly made assumptions to show using what we call multi-exit routing contradictions in routing decisions between real routing observed in publicly available measurements and that inferred from the assumptions. Sometimes, more than 70% of multi-exit instances show incoherencies. Multi-exit routing happens when an AS uses simultaneously different routes to a destination, each passing through a different AS. Our second contribution concerns erroneous BGP routes due to misconfigurations in BGP routers related to AS_TRANS, the solution introduced to assure the compatibility with old BGP routers when the change was made to represent ASNs on 32-bits instead of 16-bits. We show that such errors are indeed present, then we show how they can affect work making use of routes carrying this ASN. Our last contribution concerns routing dynamics in the Internet. We propose a method to quantity routing dynamics in each AS, then we look on ASes that have a large proportion of dynamics. After that, we focus on the AS Level 3, one of the ASes that we observe to be most dynamic. We explain that one of the reasons of a large part of the observed dynamics is load balancing between routers that have multiple physical links between each of them.

2013-2016 Publications

• 2016
  • R. Mazloum : “La caractérisation du routage dans l’Internet à l’aide des mesures IP et BGP”, thesis, phd defence 12/12/2016, supervision Fdida, Serge, co-supervision : Friedman, Timur (2016)
• 2015
  • R. Mazloum, J. Augé, D. Rossi, T. Friedman : “Errors Announcing 32-bit ASNs in BGP Routes”, DRCN'15: 11^th International Conference on Design of Reliable Communication Networks, poster paper, Kansas City, United States, pp. 87-88, (IEEE) (2015)
• 2014
  • R. Mazloum, M.‑O. Buob, J. Augé, B. Baynat, D. Rossi, T. Friedman : “Violation of interdomain routing assumptions”, PAM 2014 - 15^th International Conference on Passive and Active Measurement, vol. 8362, Lecture Notes in Computer Science, Los Angeles,, United States, pp. 173-182, (Springer) (2014)
• 2013
  • R. Mazloum, M.‑O. Buob, J. Augé, B. Baynat, T. Friedman, D. Rossi : “On multi-exit routings and AS relationships”, ISMA 2013 - 5^th AIMS Workshop, San Diego, United States (2013)