Discovering NAT64 IPv6 Prefixes Using the Port Control Protocol (PCP)
RFC 7225
Internet Engineering Task Force (IETF) M. Boucadair
Request for Comments: 7225 France Telecom
Category: Standards Track May 2014
ISSN: 2070-1721
Discovering NAT64 IPv6 Prefixes Using the Port Control Protocol (PCP)
Abstract
This document defines a new Port Control Protocol (PCP) option to
learn the IPv6 prefix(es) used by a PCP-controlled NAT64 device to
build IPv4-converted IPv6 addresses. This option is needed for
successful communications when IPv4 addresses are used in referrals.
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/rfc7225.
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
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Boucadair Standards Track [Page 1]
RFC 7225 PCP & NAT64 May 2014
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Issues . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2.1. AAAA Synthesis by the DNS Stub-resolver . . . . . . . 4
3.2.2. Application Referrals . . . . . . . . . . . . . . . . 4
4. PREFIX64 Option . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Format . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Server's Behavior . . . . . . . . . . . . . . . . . . . . 7
4.3. Client's Behavior . . . . . . . . . . . . . . . . . . . . 9
5. Flow Examples . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1. TCP Session Initiated from an IPv6-only Host . . . . . . 10
5.2. SIP Flow Example . . . . . . . . . . . . . . . . . . . . 11
5.3. Mapping of IPv4 Address Ranges to IPv6 Prefixes . . . . . 13
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
7. Security Considerations . . . . . . . . . . . . . . . . . . . 15
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
9.1. Normative References . . . . . . . . . . . . . . . . . . 15
9.2. Informative References . . . . . . . . . . . . . . . . . 16
1. Introduction
According to [RFC6146], NAT64 uses Pref64::/n to construct
IPv4-converted IPv6 addresses as defined in [RFC6052].
This document defines a new Port Control Protocol (PCP) option
[RFC6887] to inform PCP clients about the Pref64::/n and suffix
[RFC6052] used by a PCP-controlled NAT64 device [RFC6146]. It does
so by defining a new PREFIX64 option.
This PCP option is a deterministic solution to help establish
communications between IPv6-only hosts and remote IPv4-only hosts.
Unlike [RFC7050], this option solves all the issues identified in
[RFC7051].
Some illustrative examples are provided in Section 5. Detailed
experiments conducted to assess the applicability of the PREFIX64
option for services (e.g., accessing a video server, establishing
SIP-based sessions, etc.) in NAT64 environments are available in
[EXPERIMENTS].
The use of this PCP option for NAT64 load-balancing purposes is out
of scope.
Boucadair Standards Track [Page 2]
RFC 7225 PCP & NAT64 May 2014
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119].
3. Problem Statement
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