BGP Stuck Routes Operational Experience Survey
Dear NANOG community members, We are researchers from Georgia Tech investigating the phenomenon of BGP stuck routes (also known as "zombie routes")—prefixes that persist in routing tables despite being withdrawn by their origin AS. While recent research using BGP beacons (including our work presented at IMC 2025 [1]) confirms that zombie routes occur regularly and can persist for long periods, there is a gap in understanding the operational reality of this issue. We observe the data, but we need to hear from operators to understand the real-world impact and their mitigation responses. We invite you to participate in a brief, anonymous survey to help us assess the extent and impact of this phenomenon in operational settings and to identify common practices for mitigating it. Survey Link: https://forms.office.com/r/9BuWqN0n0J Privacy & Data Usage: This survey is anonymous. We are not collecting any PII (Personally Identifiable Information) data. Thank you for your time and for your contributions to this Internet measurement study. [1] I. Xygkou, A. Chariton, X. Dimitropoulos, and A. Dainotti. "A First Look into Long-lived BGP Zombies". IMC '25. https://doi.org/10.1145/3730567.3764469 Best regards, Iliana Xygkou PhD student Georgia Institute of Technology
Thanks for sharing the survey. In addition to responding, I thought I'd share a blog we wrote late last year detailing our operational experience with stuck routing: https://blog.cloudflare.com/going-bgp-zombie-hunting/ -- Bryton Herdes Principal Network Engineer AS13335 - Cloudflare On Mon, Apr 6, 2026 at 5:02 PM Iliana Xygkou via NANOG < nanog@lists.nanog.org> wrote:
Dear NANOG community members,
We are researchers from Georgia Tech investigating the phenomenon of BGP stuck routes (also known as "zombie routes")—prefixes that persist in routing tables despite being withdrawn by their origin AS. While recent research using BGP beacons (including our work presented at IMC 2025 [1]) confirms that zombie routes occur regularly and can persist for long periods, there is a gap in understanding the operational reality of this issue. We observe the data, but we need to hear from operators to understand the real-world impact and their mitigation responses.
We invite you to participate in a brief, anonymous survey to help us assess the extent and impact of this phenomenon in operational settings and to identify common practices for mitigating it. Survey Link: https://forms.office.com/r/9BuWqN0n0J Privacy & Data Usage: This survey is anonymous. We are not collecting any PII (Personally Identifiable Information) data.
Thank you for your time and for your contributions to this Internet measurement study.
[1] I. Xygkou, A. Chariton, X. Dimitropoulos, and A. Dainotti. "A First Look into Long-lived BGP Zombies". IMC '25. https://doi.org/10.1145/3730567.3764469
Best regards, Iliana Xygkou PhD student Georgia Institute of Technology _______________________________________________ NANOG mailing list
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On Mon, Apr 06, 2026 at 09:05:23PM -0000, Iliana Xygkou via NANOG wrote:
[1] I. Xygkou, A. Chariton, X. Dimitropoulos, and A. Dainotti. "A First Look into Long-lived BGP Zombies". IMC '25. https://doi.org/10.1145/3730567.3764469
Hi, The text refering to reference 9, and reference 9 itself seems wrongly titled: those Large BGP Communities Beacons were my personal project. I was originating routes with large communities from my home router. :-) In that time period, members of my household noticed they couldn't reach certain websites, and that observatoin led to the discovery there was squatting of BGP codepoints: http://largebgpcommunities.net/2016/new-path-attribute-value/ Eventually much more codepoint assignment issues were uncovered, and the registries were updated accordingly: https://datatracker.ietf.org/doc/html/rfc8093 Kind regards, Job
participants (3)
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Bryton Herdes -
ixygkou3＠gatech.edu -
Job Snijders