IPv4 Service Continuity Prefix
RFC 7335

Document Type RFC - Proposed Standard (August 2014; No errata)
Updates RFC 6333
Last updated 2015-10-14
Replaces draft-byrne-v6ops-clatip
Stream IETF
Formats plain text pdf html bibtex
Reviews
Stream WG state Submitted to IESG for Publication
Document shepherd Fred Baker
Shepherd write-up Show (last changed 2014-05-21)
IESG IESG state RFC 7335 (Proposed Standard)
Consensus Boilerplate Yes
Telechat date
Responsible AD Joel Jaeggli
Send notices to (None)
IANA IANA review state Version Changed - Review Needed
IANA action state RFC-Ed-Ack
Internet Engineering Task Force (IETF)                          C. Byrne
Request for Comments: 7335                                   T-Mobile US
Updates: 6333                                                August 2014
Category: Standards Track
ISSN: 2070-1721

                     IPv4 Service Continuity Prefix

Abstract

   Dual-Stack Lite (DS-Lite), defined in RFC 6333, directs IANA to
   reserve 192.0.0.0/29 for the Basic Bridging BroadBand (B4) element.
   Per this memo, IANA has generalized 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 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/rfc7335.

Copyright 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
   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.

Byrne                        Standards Track                    [Page 1]
RFC 7335             IPv4 Service Continuity Prefix          August 2014

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
   2.  Conventions  . . . . . . . . . . . . . . . . . . . . . . . . .  2
   3.  The Case of 464XLAT  . . . . . . . . . . . . . . . . . . . . .  2
   4.  Choosing 192.0.0.0/29  . . . . . . . . . . . . . . . . . . . .  3
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . .  3
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  3
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  4
   8.  Normative References . . . . . . . . . . . . . . . . . . . . .  4

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 has listed 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.  Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

3.  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 customer-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.

Byrne                        Standards Track                    [Page 2]
RFC 7335             IPv4 Service Continuity Prefix          August 2014

4.  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 Address Family Transition
Show full document text