Internet Engineering Task Force (IETF) D. Hankins
Request for Comments: 6334 Google
Category: Standards Track T. Mrugalski
ISSN: 2070-1721 Gdansk University of Technology
August 2011
Dynamic Host Configuration Protocol for IPv6 (DHCPv6) Option
for Dual-Stack Lite
Abstract
This document specifies a DHCPv6 option that is meant to be used by a
Dual-Stack Lite Basic Bridging BroadBand (B4) element to discover the
IPv6 address of its corresponding Address Family Transition Router
(AFTR).
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/rfc6334.
Copyright Notice
Copyright (c) 2011 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.
Hankins & Mrugalski Standards Track [Page 1]
RFC 6334 DS-Lite DHCPv6 Option August 2011
Table of Contents
1. Introduction ....................................................2
2. Requirements Language ...........................................2
3. The AFTR-Name DHCPv6 Option .....................................2
4. DHCPv6 Server Behavior ..........................................4
5. DHCPv6 Client Behavior ..........................................4
6. Security Considerations .........................................5
7. IANA Considerations .............................................6
8. Acknowledgements ................................................6
9. Normative References ............................................6
1. Introduction
Dual-Stack Lite [RFC6333] is a solution to offer both IPv4 and IPv6
connectivity to customers that are addressed only with an IPv6 prefix
(no IPv4 address is assigned to the attachment device). One of its
key components is an IPv4-over-IPv6 tunnel, commonly referred to as a
softwire. A DS-Lite "Basic Bridging BroadBand" (B4) device will not
know if the network it is attached to offers Dual-Stack Lite service,
and if it did would not know the remote endpoint of the tunnel to
establish a softwire.
To inform the B4 of the Address Family Transition Router's (AFTR)
location, a DNS [RFC1035] hostname may be used. Once this
information is conveyed, the presence of the configuration indicating
the AFTR's location also informs a host to initiate Dual-Stack Lite
(DS-Lite) service and become a softwire initiator.
To provide the conveyance of the configuration information, a single
DHCPv6 [RFC3315] option is used, expressing the AFTR's Fully
Qualified Domain Name (FQDN) to the B4 element.
The details of how the B4 establishes an IPv4-in-IPv6 softwire to the
AFTR are out of scope for this document.
2. 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 RFC 2119 [RFC2119].
3. The AFTR-Name DHCPv6 Option
The AFTR-Name option consists of option-code and option-len fields
(as all DHCPv6 options have), and a variable-length tunnel-endpoint-
name field containing a fully qualified domain name that refers to
the AFTR to which the client MAY connect.
Hankins & Mrugalski Standards Track [Page 2]
RFC 6334 DS-Lite DHCPv6 Option August 2011
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