Duplicate Address Detection Proxy
RFC 6957
Internet Engineering Task Force (IETF) F. Costa
Request for Comments: 6957 J-M. Combes, Ed.
Category: Standards Track X. Pougnard
ISSN: 2070-1721 France Telecom Orange
H. Li
Huawei Technologies
June 2013
Duplicate Address Detection Proxy
Abstract
The document describes a proxy-based mechanism allowing the use of
Duplicate Address Detection (DAD) by IPv6 nodes in a point-to-
multipoint architecture with a "split-horizon" forwarding scheme,
primarily deployed for Digital Subscriber Line (DSL) and Fiber access
architectures. Based on the DAD signaling, the first-hop router
stores in a Binding Table all known IPv6 addresses used on a point-
to-multipoint domain (e.g., VLAN). When a node performs DAD for an
address already used by another node, the first-hop router defends
the address rather than the device using the address.
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/rfc6957.
Costa, et al. Standards Track [Page 1]
RFC 6957 DAD-Proxy June 2013
Copyright Notice
Copyright (c) 2013 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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Background . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Why Existing IETF Solutions Are Not Sufficient . . . . . . . 4
3.1. Duplicate Address Detection . . . . . . . . . . . . . . . 4
3.2. Neighbor Discovery Proxy . . . . . . . . . . . . . . . . 5
3.3. 6LoWPAN Neighbor Discovery . . . . . . . . . . . . . . . 5
3.4. IPv6 Mobility Manager . . . . . . . . . . . . . . . . . . 6
4. Duplicate Address Detection Proxy (DAD-Proxy) Specifications 6
4.1. DAD-Proxy Data Structure . . . . . . . . . . . . . . . . 6
4.2. DAD-Proxy Mechanism . . . . . . . . . . . . . . . . . . . 7
4.2.1. No Entry Exists for the Tentative Address . . . . . . 7
4.2.2. An Entry Already Exists for the Tentative Address . . 7
4.2.3. Confirmation of Reachability to Check the Validity of
the Conflict . . . . . . . . . . . . . . . . . . . . 9
5. Manageability Considerations . . . . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6.1. Interoperability with SEND . . . . . . . . . . . . . . . 11
6.2. Protection against IP Source Address Spoofing . . . . . . 11
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1. Normative References . . . . . . . . . . . . . . . . . . 12
8.2. Informative References . . . . . . . . . . . . . . . . . 12
Appendix A. DAD-Proxy State Machine . . . . . . . . . . . . . . 14
Costa, et al. Standards Track [Page 2]
RFC 6957 DAD-Proxy June 2013
1. Introduction
This document specifies a function called Duplicate Address Detection
(DAD) proxy allowing the use of DAD by the nodes on the same point-
to-multipoint domain with a "split-horizon" forwarding scheme,
primarily deployed for Digital Subscriber Line (DSL) and Fiber access
architectures [TR-101]. It only impacts the first-hop router and it
doesn't need modifications on the other IPv6 nodes. This mechanism
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