—Configuration of the routing is critical for the quality and reliability of the communication in a large IP backbone. Large traffic shifts can occur due to changes in the Inter-domain routing that are hard to control by the network operator. This paper describes a framework for modeling potential traffic shifts due to BGP reroutes, calculating worst-case traffic scenarios, and finding a single routing configuration that is robust against all possible traffic shifts due to BGP reroutes. The benefit of our approach is illustrated using BGP routing updates and network topology from an operational IP network. Experiments demonstrate that the robust routing is able to obtain a consistently strong performance under large Inter-domain routing changes.