Locating BGP missing routes using multiple perspectives

Abstract

There have been many studies on measuring and interpreting interdomain routing dynamics. Most of them, however, are based on the approach of off-line and passive post-processing BGP routing updates. We propose a new methodology that uses real-time and active monitoring to troubleshoot various BGP routing anomalies. This paper focuses on a specific BGP routing problem - missing routes that occur when some ASes can reach a prefix while others can't. The idea is to periodically monitor the BGP routing status at multiple vantage points, like Route Views, and when a possible missing route event is detected issue traceroute queries from various looking glasses to learn of the packet-forwarding path status. By comparing previous and current packet-forwarding paths, we can have an idea of where the missing route event takes place. This paper examines the plausibility of this methodology and discusses preliminary experimental results.