This talk presents an analysis of the influence of intradomain routing changes in BGP in the AT&T domestic backbone. We propose a general methodology for associating BGP update messages with events visible in OSPF. Then, we apply our methodology to streams of OSPF link-state advertisements and BGP update messages from the AT&T network.

Our analysis shows that

1. "Hot potato" routing is sometimes a significant source of BGP updates.
2. BGP updates can lag 60 seconds or more behind the related intradomain change, which can cause delays in forwarding-plane convergence and introduce inaccuracy in active measurements of the customer experience.
3. The number of BGP path changes triggered by hot-potato routing has a nearly uniform distribution across destination prefixes.
4. The fraction of BGP messages triggered by OSPF varies significantly across time and router locations, with important implications on external monitoring of BGP.

About the Presenter
Renata Teixeira is a Ph.D. student at the University of California, San Diego, in the Department of Computer Science and Engineering. She received her B.Sc. in Computer Science and M.Sc. in Electrical Engineering from Universidade Federal do Rio de Janeiro, Brazil, in 1997 and 1999, respectively. Her research interests are in measurement and analysis of routing protocols, and in management of large IP networks.