Publishing End-Site Prefix Lengths
RFC 9977, “Publishing End-Site Prefix Lengths”, is a Proposed Standard document published in May 2026 by O. Gasser, R. Bush, M. Candela, R. Housley. The canonical text is published by the RFC Editor.
Abstract
This document specifies how to augment the Routing Policy Specification Language (RPSL) inetnum: class to refer specifically to prefixlen files, which are Comma-Separated Values (CSV) files used to specify end-site prefix lengths. This document also describes an optional mechanism that uses the Resource Public Key Infrastructure (RPKI) to authenticate the prefixlen files.
What “Proposed Standard” means
An entry-level standards-track specification: stable, peer-reviewed and a solid basis for implementation, though it may still evolve before becoming an Internet Standard.
The canonical text of RFC 9977 is hosted at rfc-editor.org. Available in HTML,TXT,PDF,XML.
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