OSPF Prefix Originator Extension
draft-ietf-lsr-ospf-prefix-originator-04

Document Type Active Internet-Draft (lsr WG)
Last updated 2019-09-12
Replaces draft-wang-lsr-ospf-prefix-originator-ext
Stream IETF
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LSR Working Group                                                A. Wang
Internet-Draft                                             China Telecom
Intended status: Standards Track                               A. Lindem
Expires: March 15, 2020                                    Cisco Systems
                                                                 J. Dong
                                                     Huawei Technologies
                                                               P. Psenak
                                                           K. Talaulikar
                                                           Cisco Systems
                                                      September 12, 2019

                    OSPF Prefix Originator Extension
                draft-ietf-lsr-ospf-prefix-originator-04

Abstract

   This document defines Open Shortest Path First (OSPF) encodings to
   advertise the router-id of the originator of inter-area prefixes for
   OSPFv2 and OSPFv3 Link-State Advertisements (LSAs).  The source
   originator is needed in several multi-area OSPF use cases.

Status of This Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   This Internet-Draft will expire on March 15, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents

Wang, et al.             Expires March 15, 2020                 [Page 1]
Internet-Draft           OSPF Prefix Originator           September 2019

   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Inter-Area Prefix Source Advertisement Use Cases  . . . . . .   4
   5.  Prefix Source Router-ID sub-TLV . . . . . . . . . . . . . . .   5
   6.  Elements of Procedure . . . . . . . . . . . . . . . . . . . .   6
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   9.  Acknowledgement . . . . . . . . . . . . . . . . . . . . . . .   7
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   7
     10.2.  Informative References . . . . . . . . . . . . . . . . .   9
   Appendix A.  Inter-Area Topology Retrieval Process  . . . . . . .   9
   Appendix B.  Special Considerations on Inter-Area Topology
                Retrieval  . . . . . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   [I-D.ietf-ospf-mpls-elc] defines mechanisms to advertise Entropy
   Readable Label Depth (ERLD) for ingress Label Switching Routers (LSR)
   to discover other LSR's capability of performing Entropy Label based
   load-balancing in MPLS networks.  The ingress LSR can use this
   information to construct the appropriate label stack for specific
   traffic requirements, especially in segment routed networks and other
   deployments requiring stacked LSPs.

   However, in inter-area scenarios, the Area Border Router (ABR) does
   not advertise the originating OSPF router-id for inter-area prefixes.
   An OSPF router in one area doesn't know the origin area of inter-area
   prefixes and can't determine the router that originated these
   prefixes or the ERLD capabilities of the destination.  Therefore, it
   is necessary to advertise the originator of these inter-area prefixes
   to ensure the ingress LSR can construct the appropriate label stack.

   More generally, [RFC8476] defines a mechanism to advertise multiple
   types of supported Maximum SID Depths (MSD) at node and/or link
   granularity.  This information will be referred when the head-end
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