INTERNET-DRAFT                                             Cameron Byrne
Updates: [RFC6333] (if approved)                             T-Mobile US
Intended Status: Standards Track                            May 27, 2014
Expires: November 28, 2014


                    IPv4 Service Continuity Prefix
                       draft-ietf-v6ops-clatip-02


Abstract

   DS-Lite, defined in RFC 6333,  directs IANA to reserve 192.0.0.0/29
   for the B4 element.  This memo directs IANA to generalize that
   reservation to include other cases where a non-routed IPv4 interface
   must be numbered as part of an IPv6 transition solution.


Status of this Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
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   Internet-Drafts.

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Copyright and License Notice

   Copyright (c) 2014 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



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   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 . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  The Case of 464XLAT  . . . . . . . . . . . . . . . . . . . . .  3
   3.  Choosing 192.0.0.0/29  . . . . . . . . . . . . . . . . . . . .  3
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . .  3
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  4
   6.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  4
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . .  4
     7.1.  Normative References . . . . . . . . . . . . . . . . . . .  4
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . .  4































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1.  Introduction

   DS-Lite [RFC6333] directs IANA to reserve 192.0.0.0/29 for the Basic
   Bridging BroadBand (B4) element.  This memo generalizes that IANA
   reservation to include other cases where a non-routed IPv4 interface
   must be numbered in an IPv6 transition solution.  IANA shall list the
   address block 192.0.0.0/29 reserved for IPv4 Service Continuity
   Prefix.  The result is that 192.0.0.0/29 may be used in any system
   that requires IPv4 addresses for backward compatibility with IPv4
   communications in an IPv6-only network, but does not emit IPv4
   packets "on the wire".

   This generalization does not impact the use of the IPv4 Service
   Continuity Prefix in a DS-Lite context.

2.  The Case of 464XLAT

   464XLAT [RFC6877] describes an architecture for providing IPv4
   communication over an IPv6-only access network.  One of the methods
   described in [RFC6877] is for the client side translator (CLAT) to be
   embedded in the host, such as a smartphone or a CPE (Customer
   Premises Equipment).  In such scenarios, the host must have an IPv4
   address configured to present to the host network stack and for
   applications to bind IPv4 sockets.

3.  Choosing 192.0.0.0/29

   To avoid conflicts with any other network that may communicate with
   the CLAT or other IPv6 transition solution, a locally unique IPv4
   address must be assigned.

   IANA has defined a well-known range, 192.0.0.0/29, in [RFC6333],
   which is dedicated for DS-Lite.  As defined in [RFC6333], this subnet
   is only present between the B4 and the AFTR and never emits packets
   from this prefix "on the wire".  464XLAT has the same need for a non-
   routed IPv4 prefix, and this same need may be common for other
   similar solutions.  It is most prudent and effective to generalize
   192.0.0.0/29 for the use of supporting IPv4 interfaces in IPv6
   transition technologies rather than reserving a prefix for every
   possible solution.

   With this memo, 192.0.0.0/29 is now generalized across multiple IPv4
   continuity solutions such as 464XLAT and DS-lite.  It is important
   that a host never enable 2 active IPv4 continuity solutions
   simultaneously in a way that would cause a node to have overlapping
   address from 192.0.0.0/29.

4.  Security Considerations



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   No new security considerations beyond what is described [RFC6333] and
   [RFC6877].


5.  IANA Considerations


   This document requests IANA to update the IPv4 Special-Purpose
   Address Registry available at (http://www.iana.org/assignments/iana-
   ipv4-special-registry/iana-ipv4-special-registry.xhtml) as follows:

   OLD:

   192.0.0.0/29         DS-Lite         [RFC6333]

   NEW:

   192.0.0.0/29         IPv4 Service Continuity Prefix  [RFC-to-be-xxx]


6.  Acknowledgements

   This document has been substantially improved by specific feedback
   from Dave Thaler, Fred Baker, Wes George, Lorenzo Colitti, and
   Mohamed Boucadair.

7.  References

7.1.  Normative References

   [RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
              Stack Lite Broadband Deployments Following IPv4
              Exhaustion", RFC6333, August 2011.

   [RFC6877]  Mawatari, M., Kawashima, M., and C. Byrne, "464XLAT:
              Combination of Stateful and Stateless Translation",
              RFC6877, April 2013.



Authors' Addresses


              Cameron Byrne
              Bellevue, WA, USA
              Email: Cameron.Byrne@T-Mobile.com





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