Prefix Flag Extension for OSPFv2 and OSPFv3
RFC 9792, “Prefix Flag Extension for OSPFv2 and OSPFv3”, is a Proposed Standard document published in June 2025 by R. Chen, D. Zhao, P. Psenak, K. Talaulikar, L. Gong. The canonical text is published by the RFC Editor.
Abstract
Each OSPF prefix can be advertised with an 8-bit field to indicate specific properties of that prefix. However, all the OSPFv3 Prefix Options bits have already been assigned, and only a few bits remain unassigned in the Flags field of the OSPFv2 Extended Prefix TLV.
This document solves this problem by defining a variable-length Prefix Extended Flags sub-TLV for OSPF. This sub-TLV is applicable to OSPFv2 and OSPFv3.
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 9792 is hosted at rfc-editor.org. Available in HTML,TXT,PDF,XML.
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