12:45 PM, Thursday, November 29th, 2001
Room 104, Gates Computer Science Building

A Measurement Study of BGP Misconfiguration

David Wetherall (Speaker), Ratul Mahajan, and Tom Anderson
University of Washington

Slides:[PDF]

About the talk:

How can we build Internet routing protocols that are not fragile in the face of simple configuration errors? To gain insight into this problem, we are studying how BGP is used in practice. It is well-known that BGP is vulnerable to accidental misconfigurations that can result in widespread loss of connectivity, yet most of the evidence for this remains anecdotal. In this talk, we present preliminary results of a new measurement study of BGP, based on publicly available routing table snapshots and looking glasses. The goal of our study is to quantify the amount of misconfiguration and its impact on the Internet.

We have focused on two classes of misconfiguration so far: announcements with incorrect origins, where the route appears to lead to the wrong place; and partial connectivity, where address space is reachable from only some regions of the Internet. We find that there are a significant number of announcements with questionable origins, accounting for roughly 1% of the announced prefixes. Yet despite this, BGP is surprisingly robust in the sense that the majority of these misconfigurations do not result in a loss of connectivity that is visible to the end user. We also find that approximately 1-2% of the address space exists in a persistently partially reachable state at any given time due to route filtering and damping practices. At the end of the talk, I will speculate on the implications of our study for the design of more robust routing protocols.

About the speaker:

David Wetherall joined the faculty at the University of Washington as an Assistant Professor in June 1999. In addition to his role in the Computer Science and Engineering department, he is Chief Architect at Asta Networks, a startup that he co-founded in June 2000. Before coming to UW, David received his Ph.D. in computer science from MIT in 1998 for pioneering research on active networks, an architecture in which new network services can be introduced rapidly using mobile code. He received his S.M. in computer science from MIT in 1994, and his B.E. in electrical engineering from the University of Western Australia in 1989.