IPv6 Rapid Deployment on IPv4 Infrastructures (6rd) -- Protocol Specification
RFC 5969

Internet Engineering Task Force (IETF)                       W. Townsley
Request for Comments: 5969                                      O. Troan
Category: Standards Track                                          Cisco
ISSN: 2070-1721                                              August 2010

         IPv6 Rapid Deployment on IPv4 Infrastructures (6rd) --
                         Protocol Specification

Abstract

   This document specifies an automatic tunneling mechanism tailored to
   advance deployment of IPv6 to end users via a service provider's IPv4
   network infrastructure.  Key aspects include automatic IPv6 prefix
   delegation to sites, stateless operation, simple provisioning, and
   service, which is equivalent to native IPv6 at the sites that are
   served by the mechanism.

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/rfc5969.

Copyright Notice

   Copyright (c) 2010 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
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   (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
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Townsley & Troan             Standards Track                    [Page 1]
RFC 5969                           6rd                       August 2010

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
   2.  Requirements Language  . . . . . . . . . . . . . . . . . . . .  4
   3.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  6rd Prefix Delegation  . . . . . . . . . . . . . . . . . . . .  5
   5.  Troubleshooting and Traceability . . . . . . . . . . . . . . .  7
   6.  Address Selection  . . . . . . . . . . . . . . . . . . . . . .  7
   7.  6rd Configuration  . . . . . . . . . . . . . . . . . . . . . .  7
     7.1.  Customer Edge Configuration  . . . . . . . . . . . . . . .  8
       7.1.1.  6rd DHCPv4 Option  . . . . . . . . . . . . . . . . . .  9
     7.2.  Border Relay Configuration . . . . . . . . . . . . . . . . 10
   8.  Neighbor Unreachability Detection  . . . . . . . . . . . . . . 11
   9.  IPv6 in IPv4 Encapsulation . . . . . . . . . . . . . . . . . . 12
     9.1.  Maximum Transmission Unit  . . . . . . . . . . . . . . . . 13
     9.2.  Receiving Rules  . . . . . . . . . . . . . . . . . . . . . 13
   10. Transition Considerations  . . . . . . . . . . . . . . . . . . 14
   11. IPv6 Address Space Usage . . . . . . . . . . . . . . . . . . . 14
   12. Security Considerations  . . . . . . . . . . . . . . . . . . . 15
   13. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 16
   14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16
   15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16
     15.1. Normative References . . . . . . . . . . . . . . . . . . . 16
     15.2. Informative References . . . . . . . . . . . . . . . . . . 17

1.  Introduction

   The original idea and the name of the mechanism (6rd) described in
   [RFC5569] details a successful commercial "rapid deployment" of the
   6rd mechanism by a residential service provider and is recommended
   reading.  This document describes the 6rd mechanism, which has been
   extended for use in more general environments.  Throughout this
   document, the term 6to4 is used to refer to the mechanism described
   in [RFC3056] and 6rd is the mechanism defined herein.

   6rd specifies a protocol mechanism to deploy IPv6 to sites via a
   service provider's (SP's) IPv4 network.  It builds on 6to4 [RFC3056],
   with the key differentiator that it utilizes an SP's own IPv6 address
   prefix rather than a well-known prefix (2002::/16).  By using the
   SP's IPv6 prefix, the operational domain of 6rd is limited to the SP
   network and is under its direct control.  From the perspective of
   customer sites and the IPv6 Internet at large, the IPv6 service