INTERNET-DRAFT                                             Cameron Byrne
Intended Status: Informational                               T-Mobile US
Expires: November 6, 2014                                    May 5, 2014


                    IPv4 Service Continuity Prefix
                       draft-ietf-v6ops-clatip-00


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

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   Copyright (c) 2014 IETF Trust and the persons identified as the
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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document. Please review these documents



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   carefully, as they describe your rights and restrictions with respect
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   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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  Introduction

   DS-Lite [RFC6333] directs IANA to reserve 192.0.0.0/29 for the 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".

  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.  In this scenario, the
   host must have an IPv4 address configured to present to the host
   network stack and for applications to bind sockets.

.  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 be deployed with 2 active IPv4 continuity solutions
   simultaneously in a way that would cause a node to have overlapping
   address from 192.0.0.0/29.

  Security Considerations

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





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  IANA Considerations

   IANA is directed to generalize the reservation of 192.0.0.0/29 from
   DS-lite to "IPv4 Service Continuity Prefix".

  Acknowledgements

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

  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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