Gateway-Initiated Dual-Stack Lite Deployment
RFC 6674
Internet Engineering Task Force (IETF) F. Brockners
Request for Comments: 6674 S. Gundavelli
Category: Standards Track Cisco
ISSN: 2070-1721 S. Speicher
Deutsche Telekom AG
D. Ward
Cisco
July 2012
Gateway-Initiated Dual-Stack Lite Deployment
Abstract
Gateway-Initiated Dual-Stack Lite (GI-DS-Lite) is a variant of Dual-
Stack Lite (DS-Lite) applicable to certain tunnel-based access
architectures. GI-DS-Lite extends existing access tunnels beyond the
access gateway to an IPv4-IPv4 NAT using softwires with an embedded
Context Identifier that uniquely identifies the end-system to which
the tunneled packets belong. The access gateway determines which
portion of the traffic requires NAT using local policies and sends/
receives this portion to/from this softwire.
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/rfc6674.
Brockners, et al. Standards Track [Page 1]
RFC 6674 Gateway-Initiated DS-Lite July 2012
Copyright Notice
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Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Gateway-Initiated DS-Lite . . . . . . . . . . . . . . . . . . 4
4. Protocol and Related Considerations . . . . . . . . . . . . . 6
5. Softwire Management and Related Considerations . . . . . . . . 7
6. Softwire Embodiments . . . . . . . . . . . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . 10
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
9.1. Normative References . . . . . . . . . . . . . . . . . . . 11
9.2. Informative References . . . . . . . . . . . . . . . . . . 12
Appendix A. GI-DS-Lite Deployment . . . . . . . . . . . . . . . . 13
A.1. Connectivity Establishment: Example Call Flow . . . . . . 13
A.2. GI-DS-Lite Applicability: Examples . . . . . . . . . . . . 14
Brockners, et al. Standards Track [Page 2]
RFC 6674 Gateway-Initiated DS-Lite July 2012
1. Overview
Gateway-Initiated Dual-Stack Lite (GI-DS-Lite) is a variant of Dual-
Stack Lite (DS-Lite) [RFC6333], applicable to network architectures
that use point-to-point tunnels between the access device and the
access gateway. The access gateway in these models is designed to
serve large numbers of access devices. Mobile architectures based on
Mobile IPv6 [RFC6275], Proxy Mobile IPv6 [RFC5213], or GPRS
Tunnelling Protocol (GTP) [TS29060], as well as broadband
architectures based on PPP or point-to-point VLANs as defined by the
Broadband Forum [TR59][TR101], are examples of this type of
architecture.
The DS-Lite approach leverages IPv4-in-IPv6 tunnels (or other
tunneling modes) for carrying the IPv4 traffic from the customer
network to the Address Family Transition Router (AFTR). An
established softwire between the AFTR and the access device is used
for traffic-forwarding purposes. This makes the inner IPv4 address
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