Extensions to OSPF for Advertising Prefix Administrative Tags
RFC 9825, “Extensions to OSPF for Advertising Prefix Administrative Tags”, is a Proposed Standard document published in July 2025 by A. Lindem, P. Psenak, Y. Qu. The canonical text is published by the RFC Editor.
Abstract
It is useful for routers in OSPFv2 and OSPFv3 routing domains to be able to associate tags with prefixes. Previously, OSPFv2 and OSPFv3 were relegated to a single tag and only for Autonomous System (AS) External and Not-So-Stubby-Area (NSSA) prefixes. With the flexible encodings provided by OSPFv2 Prefix/Link Attribute Advertisement and OSPFv3 Extended Link State Advertisements (LSAs), multiple administrative tags may be advertised for all types of prefixes. These administrative tags can be used for many applications including route redistribution policy, selective prefix prioritization, selective IP Fast Reroute (IPFRR) prefix protection, and many others.
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 9825 is hosted at rfc-editor.org. Available in HTML,TXT,PDF,XML.
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