1. Introduction

Cette page resume la section correspondante du RFC 9983 et conserve les points essentiels sur OSPFv2, AC-Flag, IANA et YANG.

An IP prefix may be configured as anycast, and the same value can be advertised by multiple routers. Other routers benefit from knowing that an advertisement is for an anycast prefix.

[RFC7684] defines OSPFv2 Opaque Link State Advertisements (LSAs) based on Type-Length-Value (TLV) tuples. The OSPFv2 Extended Prefix TLV in the OSPFv2 Extended Prefix Opaque LSA advertises additional attributes associated with a prefix.

IS-IS [RFC9352] and OSPFv3 [RFC9513] already have extensions related to the anycast property of prefixes. This document defines a flag for OSPFv2 in the Flags field of the OSPFv2 Extended Prefix TLV Flags and specifies a companion YANG module.