Recommendations for Prefix Binding in the Context of Softwire Dual-Stack Lite
RFC 7785

Document Type RFC - Informational (February 2016; No errata)
Last updated 2016-02-16
Stream ISE
Formats plain text pdf html bibtex
Reviews
IETF conflict review conflict-review-vinapamula-softwire-dslite-prefix-binding
Stream ISE state Published RFC
Consensus Boilerplate Yes
Document shepherd Nevil Brownlee
Shepherd write-up Show (last changed 2015-11-04)
IESG IESG state RFC 7785 (Informational)
Telechat date
Responsible AD Terry Manderson
Send notices to (None)
IANA IANA review state IANA OK - No Actions Needed
IANA action state No IC
Independent Submission                                     S. Vinapamula
Request for Comments: 7785                              Juniper Networks
Category: Informational                                     M. Boucadair
ISSN: 2070-1721                                                   Orange
                                                           February 2016

                   Recommendations for Prefix Binding
               in the Context of Softwire Dual-Stack Lite

Abstract

   This document discusses issues induced by the change of the Dual-
   Stack Lite (DS-Lite) Basic Bridging BroadBand (B4) IPv6 address and
   sketches a set of recommendations to solve those issues.

Status of This Memo

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

   This is a contribution to the RFC Series, independently of any other
   RFC stream.  The RFC Editor has chosen to publish this document at
   its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not 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/rfc7785.

Copyright Notice

   Copyright (c) 2016 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.

Vinapamula & Boucadair        Informational                     [Page 1]
RFC 7785               Prefix Binding for DS-Lite          February 2016

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  The Problem . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Introducing Subscriber-Mask . . . . . . . . . . . . . . . . .   4
   4.  Recommendations . . . . . . . . . . . . . . . . . . . . . . .   5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   6.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .   6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   IPv6 deployment models assume IPv6 prefixes are delegated by Service
   Providers to the connected CPEs (Customer Premises Equipment) or
   hosts, which in turn derive IPv6 addresses from that prefix.  In the
   case of Dual-Stack Lite (DS-Lite) [RFC6333], which is an IPv4 service
   continuity mechanism over an IPv6 network, the Basic Bridging
   BroadBand (B4) element derives an IPv6 address for the IPv4-in-IPv6
   softwire setup purposes.

   The B4 element might obtain a new IPv6 address for a variety of
   reasons that include (but are not limited to) a reboot of the CPE,
   power outage, DHCPv6 lease expiry, or other actions undertaken by the
   Service Provider.  If this occurs, traffic forwarded to a B4's
   previous IPv6 address may never reach its destination or may be
   delivered to another B4 that now uses the address formerly assigned
   to the original B4.  This situation affects all mapping types, both
   implicit (e.g., by sending a TCP SYN) and explicit (e.g., using Port
   Control Protocol (PCP) [RFC6887]).  The problem is further elaborated
   in Section 2.

   This document proposes recommendations to soften the impact of such
   renumbering issues (Section 4).

   This document complements [RFC6908].

1.1.  Requirements Language

   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].

Vinapamula & Boucadair        Informational                     [Page 2]
RFC 7785               Prefix Binding for DS-Lite          February 2016

2.  The Problem

   Since private IPv4 addresses assigned to hosts serviced by a B4
Show full document text