Host Router Support for OSPFv2
draft-ietf-ospf-ospfv2-hbit-10

Document Type Active Internet-Draft (lsr WG)
Last updated 2019-11-07 (latest revision 2019-10-24)
Replaces draft-keyupate-ospf-ospfv2-hbit
Stream IETF
Intended RFC status Proposed Standard
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Reviews
Stream WG state Submitted to IESG for Publication
Document shepherd Yingzhen Qu
Shepherd write-up Show (last changed 2018-12-05)
IESG IESG state IESG Evaluation
Consensus Boilerplate Yes
Telechat date On agenda of 2019-12-05 IESG telechat
Needs 9 more YES or NO OBJECTION positions to pass.
Responsible AD Alvaro Retana
Send notices to Yingzhen Qu <yingzhen.ietf@gmail.com>, aretana.ietf@gmail.com
IANA IANA review state IANA OK - Actions Needed
OSPF                                                            K. Patel
Internet-Draft                                                    Arrcus
Updates: 6987 (if approved)                            P. Pillay-Esnault
Intended status: Standards Track                          PPE Consulting
Expires: April 26, 2020                                      M. Bhardwaj
                                                            S. Bayraktar
                                                           Cisco Systems
                                                        October 24, 2019

                     Host Router Support for OSPFv2
                     draft-ietf-ospf-ospfv2-hbit-10

Abstract

   The Open Shortest Path First Version 2 (OSPFv2) does not have a
   mechanism for a node to repel transit traffic if it is on the
   shortest path.  This document defines a bit (Host-bit) that enables a
   router to advertise that it is a non-transit router."  It also
   describes the changes needed to support the H-bit in the domain.  In
   addition, this document updates RFC 6987 to advertise type-2 External
   and NSSA LSAs with a high cost in order to repel traffic effectively.

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
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   This Internet-Draft will expire on April 26, 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

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Internet-Draft                                              October 2019

   publication of this document.  Please review these documents
   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.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  Host-bit Support  . . . . . . . . . . . . . . . . . . . . . .   3
   4.  SPF Modifications . . . . . . . . . . . . . . . . . . . . . .   5
   5.  Auto Discovery and Backward Compatibility . . . . . . . . . .   6
   6.  OSPF AS-External-LSAs/NSSA LSAs with Type 2 Metrics . . . . .   7
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   8
     10.2.  Informative References . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   The OSPFv2 specifies a Shortest Path First (SPF) algorithm that
   identifies transit vertices based on their adjacencies.  Therefore,
   OSPFv2 does not have a mechanism to prevent traffic transiting a
   participating node if it is a transit vertex in the only existing or
   shortest path to the destination.  The use of metrics to make the
   node undesirable can help to repel traffic only if an alternative
   better route exists.

   This functionality is particularly useful for a number of use cases:

   1.  To isolate a router to avoid blackhole scenarios when there is a
       reload and possible long reconvergence times.

   2.  Closet Switches are usually not used for transit traffic but need
       to participate in the topology.

   3.  Overloaded routers could use such a capability to temporarily
       repel traffic until they stabilize.

   4.  BGP Route reflectors known as virtual Route Reflectors (vRRs),
       that are not in the forwarding path but are in central locations
       such as data centers.  Such Route Reflectors typically are used
       for route distribution and are not capable of forwarding transit

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Internet-Draft                                              October 2019
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