Cloudflare evaluated RFC 9234 adoption on the Internet, discovering that two Tier-1 networks (GTT and Arelion) were stripping the OTC attribute, and began engaging with them to fix the issue.

Key Details

• Cloudflare used BMP feeds and public BGP collectors (RouteViews, RIPE RIS) to study RFC 9234 adoption
• 67 ASes were found setting the OTC attribute from Cloudflare's direct peering analysis
• GTT (AS3257) and Arelion (AS1299) identified as two Tier-1 ASes stripping the OTC attribute
• 33.1% of IPv4 and 17% of IPv6 AS_PATHs had their OTC attribute dropped
• Both GTT and Arelion confirmed OTC stripping was due to defensive practices from past BGP error-handling incidents
• Arelion rolled out fixes to preserve OTC after Cloudflare's engagement
• GTT continues to strip the OTC attribute as of August 2026
• YYCIX was the first route server to deploy RFC 9234
• Cloudflare has started gradual deployment of RFC 9234 across its global router fleet
• Cloudflare plans to publish RFC 9234 adoption data publicly in Cloudflare Radar's Routing section

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