Extensions to OSPF for Advertising Prefix/Link Administrative Tags
draft-acee-ospf-admin-tags-06

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Network Working Group                                     A. Lindem, Ed.
Internet-Draft                                                 P. Psenak
Intended status: Standards Track                           Cisco Systems
Expires: March 27, 2021                               September 23, 2020

   Extensions to OSPF for Advertising Prefix/Link Administrative Tags
                     draft-acee-ospf-admin-tags-06

Abstract

   It is useful for routers in an OSPFv2 or OSPFv3 routing domain to be
   able to associate tags with prefixes and links.  Previously, OSPFv2
   and OSPFv3 were relegated to a single tag for AS External and Not-So-
   Stubby-Area (NSSA) prefixes.  With the flexible encodings provided by
   OSPFv2 Prefix/Link Attribute Advertisement and OSPFv3 Extended LSAs,
   multiple administrative tags may advertised for all types of prefixes
   and links.  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.

   The ISIS protocol supports a similar mechanism that is described in
   RFC 5130.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on March 27, 2021.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Lindem & Psenak          Expires March 27, 2021                 [Page 1]
Internet-Draft          OSPF Administrative Tags          September 2020

   This document is subject to BCP 78 and the IETF Trust's Legal
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   (https://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements notation . . . . . . . . . . . . . . . . . .   3
   2.  32-Bit Administrative Tag Sub-TLV . . . . . . . . . . . . . .   3
   3.  Administrative Tag Applicability  . . . . . . . . . . . . . .   4
   4.  Protocol Operation  . . . . . . . . . . . . . . . . . . . . .   5
     4.1.  Equal-Cost Multipath Applicability  . . . . . . . . . . .   5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   6
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Appendix A.  64-Bit Administrative Tag Sub-TLV  . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   It is useful for routers in an OSPFv2 [RFC2328] or OSPFv3 [RFC5340]
   routing domain to be able to associate tags with prefixes and links.
   Previously, OSPFv3 and OSPFv3 were relegated to a single tag for AS
   External and Not-So-Stubby-Area (NSSA) prefixes.  With the flexible
   encodings provided by OSPFv2 Prefix/Link Attribute Advertisement
   ([RFC7684]) and OSPFv3 Extended LSA ([RFC8362]), multiple
   administrative tags may be advertised for all types of prefixes and
   links.  These administrative tags can be used many applications
   including (but not limited to):

   1.  Controlling which routes are redistributed into other protocols
       for readvertisement.

   2.  Prioritizing selected prefixes for faster convergence and
       installation in the forwarding plane.

   3.  Identifying selected prefixes for Loop-Free Alternative (LFA)
       protection.

Lindem & Psenak          Expires March 27, 2021                 [Page 2]
Internet-Draft          OSPF Administrative Tags          September 2020

   Throughout this document, OSPF is used when the text applies to both
   OSPFv2 and OSPFv3.  OSPFv2 or OSPFv3 is used when the text is
   specific to one version of the OSPF protocol.