Enhanced Duplicate Address Detection
RFC 7527

 
Document Type RFC - Proposed Standard (April 2015; No errata)
Last updated 2015-04-24
Replaces draft-hsingh-6man-enhanced-dad
Stream IETF
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Stream WG state Submitted to IESG for Publication
Consensus Yes
Document shepherd Ole Troan
Shepherd write-up Show (last changed 2014-11-11)
IESG IESG state RFC 7527 (Proposed Standard)
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Responsible AD Brian Haberman
Send notices to 6man-chairs@ietf.org, ot@cisco.com
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Internet Engineering Task Force (IETF)                          R. Asati
Request for Comments: 7527                                      H. Singh
Updates: 4429, 4861, 4862                                      W. Beebee
Category: Standards Track                                   C. Pignataro
ISSN: 2070-1721                                      Cisco Systems, Inc.
                                                                 E. Dart
                                   Lawrence Berkeley National Laboratory
                                                               W. George
                                                       Time Warner Cable
                                                              April 2015

                  Enhanced Duplicate Address Detection

Abstract

   IPv6 Loopback Suppression and Duplicate Address Detection (DAD) are
   discussed in Appendix A of RFC 4862.  That specification mentions a
   hardware-assisted mechanism to detect looped back DAD messages.  If
   hardware cannot suppress looped back DAD messages, a software
   solution is required.  Several service provider communities have
   expressed a need for automated detection of looped back Neighbor
   Discovery (ND) messages used by DAD.  This document includes
   mitigation techniques and outlines the Enhanced DAD algorithm to
   automate the detection of looped back IPv6 ND messages used by DAD.
   For network loopback tests, the Enhanced DAD algorithm allows IPv6 to
   self-heal after a loopback is placed and removed.  Further, for
   certain access networks, this document automates resolving a specific
   duplicate address conflict.  This document updates RFCs 4429, 4861,
   and 4862.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7527.

Asati, et al.                Standards Track                    [Page 1]
RFC 7527                      Enhanced DAD                    April 2015

Copyright Notice

   Copyright (c) 2015 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
   (http://trustee.ietf.org/license-info) in effect on the date of
   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
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Operational Mitigation Options  . . . . . . . . . . . . . . .   4
     3.1.  Disable DAD on an Interface . . . . . . . . . . . . . . .   4
     3.2.  Dynamic Disable/Enable of DAD Using Layer 2 Protocol  . .   5
     3.3.  Operational Considerations  . . . . . . . . . . . . . . .   5
   4.  The Enhanced DAD Algorithm  . . . . . . . . . . . . . . . . .   6
     4.1.  Processing Rules for Senders  . . . . . . . . . . . . . .   6
     4.2.  Processing Rules for Receivers  . . . . . . . . . . . . .   7
     4.3.  Changes to RFC 4861 . . . . . . . . . . . . . . . . . . .   7
   5.  Action to Perform on Detecting a Genuine Duplicate  . . . . .   7
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .   8
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   IPv6 Loopback Suppression and Duplicate Address Detection (DAD) are
   discussed in Appendix A of [RFC4862].  That specification mentions a
   hardware-assisted mechanism to detect looped back DAD messages.  If
   hardware cannot suppress looped back DAD messages, a software
   solution is required.  One specific DAD message is the Neighbor
   Solicitation (NS), specified in [RFC4861].  The NS is issued by the
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