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Public IPv4-over-IPv6 Access Network
RFC 7040

Document type: RFC - Informational (November 2013)
Document stream: IETF
Last updated: 2013-11-11
Other versions: plain text, pdf, html

IETF State: Submitted to IESG for Publication
Consensus: Yes
Document shepherd: Suresh Krishnan
Shepherd Write-Up: Last changed 2013-05-02

IESG State: RFC 7040 (Informational)
IANA Review State: IANA OK - No Actions Needed
IANA Action State: No IC
Responsible AD: Ted Lemon
Send notices to: softwire-chairs@tools.ietf.org, draft-ietf-softwire-public-4over6@tools.ietf.org

Internet Engineering Task Force (IETF)                            Y. Cui
Request for Comments: 7040                                         J. Wu
Category: Informational                                            P. Wu
ISSN: 2070-1721                                      Tsinghua University
                                                              O. Vautrin
                                                        Juniper Networks
                                                                  Y. Lee
                                                                 Comcast
                                                           November 2013

                  Public IPv4-over-IPv6 Access Network

Abstract

   This document describes a mechanism called Public 4over6, which is
   designed to provide IPv4 Internet connectivity over an IPv6 access
   network using global IPv4 addresses.  Public 4over6 was developed in
   the IETF and is in use in some existing deployments but is not
   recommended for new deployments.  Future deployments of similar
   scenarios should use Lightweight 4over6.  Public 4over6 follows the
   Hub and Spoke softwire model and uses an IPv4-in-IPv6 tunnel to
   forward IPv4 packets over an IPv6 access network.  The
   bidirectionality of the IPv4 communication is achieved by explicitly
   allocating global non-shared IPv4 addresses to end users and by
   maintaining IPv4-IPv6 address binding on the border relay.  Public
   4over6 aims to provide uninterrupted IPv4 services to users, like
   Internet Content Providers (ICPs), etc., while an operator makes the
   access network transition to an IPv6-only access network.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   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).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see 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/rfc7040.

Cui, et al.                   Informational                     [Page 1]
RFC 7040                      Public 4over6                November 2013

Copyright Notice

   Copyright (c) 2013 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
   2. Terminology .....................................................4
   3. Scenario and Use Cases ..........................................4
   4. Public 4over6 Address Provisioning ..............................6
      4.1. Basic Provisioning Steps ...................................6
      4.2. Public IPv4 Address Allocation .............................7
   5. 4over6 CE Behavior ..............................................7
   6. 4over6 BR Behavior ..............................................8
   7. Fragmentation and Reassembly ....................................9
   8. DNS .............................................................9
   9. Security Considerations ........................................10
   10. Contributors ..................................................11
   11. References ....................................................12
      11.1. Normative References .....................................12
      11.2. Informative References ...................................12

1.  Introduction

   When operators make the access network transition to an IPv6-only
   access network, they must continue to provide IPv4 services to their
   users to access IPv4 contents.  IPv4 connectivity is required when
   communicating with the IPv4-only Internet.  This document describes a
   mechanism called Public 4over6 for providing IPv4 connectivity over a
   native IPv6-only access network.  This memo focuses on interactions
   between Public 4over6 elements as well as the deployment

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