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PSA: Removing AS-SET Ambiguity#

RIPE 93 digest Program Adjacent pick 26–30 October 2026

Abstract Slides Recording

James Bensley, Inter.link

  • Why: AS-SET names are not globally unique, and the same name can resolve differently per database (AS-APPLE in RIPE: 2 ASNs, 0 prefixes; in RADB: 2 ASNs, 244 prefixes) — producing silently empty or silently wrong prefix filters. The ecosystem has just changed a lot at once, and this rounds it up.
  • What: A public service announcement consolidating independent fixes: RIR enforcement of hierarchical AS-SET names (RIPE, APNIC and LACNIC done; AFRINIC and ARIN coming); PeeringDB requiring registry-scoped AS-SETs (with auto-suggested scope) and limiting networks to a single AS-SET (of 37,130 networks, 19,942 declare an AS-SET and 304 declared more than one); MANRS considering making both mandatory; and IETF drafts for registry-scoped members (src-members: RIPE::AS-BAR) and member exclusion (excl-members:, motivated by an AS-SET expanding to 76,337 ASNs and 1.32M prefixes).
  • How: Concrete database/policy changes already shipped or in flight, each with links to the enforcing organization and draft.
  • Where applicable: Anyone generating IRR-derived filters today — the action items (rename to hierarchical, scope your AS-SETs in PeeringDB) are immediate.