draft-ietf-6man-enhanced-dad-00.txt   draft-ietf-6man-enhanced-dad-01.txt 
Network Working Group R. Asati Network Working Group R. Asati
Internet-Draft H. Singh Internet-Draft H. Singh
Updates: 4862 (if approved) W. Beebee Updates: 4862 (if approved) W. Beebee
Intended status: Standards Track Cisco Systems, Inc. Intended status: Standards Track Cisco Systems, Inc.
Expires: October 8, 2012 E. Dart Expires: March 10, 2013 E. Dart
Lawrence Berkeley National Lawrence Berkeley National
Laboratory Laboratory
W. George W. George
Time Warner Cable Time Warner Cable
C. Pignataro C. Pignataro
Cisco Systems, Inc. Cisco Systems, Inc.
April 6, 2012 September 6, 2012
Enhanced Duplicate Address Detection Enhanced Duplicate Address Detection
draft-ietf-6man-enhanced-dad-00.txt draft-ietf-6man-enhanced-dad-01.txt
Abstract Abstract
Appendix A of the IPv6 Duplicate Address Detection (DAD) document in Appendix A of the IPv6 Duplicate Address Detection (DAD) document in
RFC 4862 discusses Loopback Suppression and DAD. However, RFC 4862 RFC 4862 discusses Loopback Suppression and DAD. However, RFC 4862
does not settle on one specific automated means to detect loopback of does not settle on one specific automated means to detect loopback of
Neighbor Discovery (ND of RFC 4861) messages used by DAD. Several Neighbor Discovery (ND of RFC 4861) messages used by DAD. Several
service provider communities have expressed a need for automated service provider communities have expressed a need for automated
detection of looped backed ND messages used by DAD. This document detection of looped backed ND messages used by DAD. This document
includes mitigation techniques and then outlines the Enhanced DAD includes mitigation techniques and then outlines the Enhanced DAD
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 8, 2012. This Internet-Draft will expire on March 10, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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One can disable DAD on an interface and then there is no NS(DAD) One can disable DAD on an interface and then there is no NS(DAD)
issued to be looped back. DAD is disabled by setting the interface's issued to be looped back. DAD is disabled by setting the interface's
DupAddrDetectTransmits variable to zero. While this mitigation may DupAddrDetectTransmits variable to zero. While this mitigation may
be the simplest the mitigation has three drawbacks. be the simplest the mitigation has three drawbacks.
It would likely require careful analysis of configuration on such It would likely require careful analysis of configuration on such
point-to-point interfaces, a one-time manual configuration on each of point-to-point interfaces, a one-time manual configuration on each of
such interfaces, and more importantly, genuine duplicates in the link such interfaces, and more importantly, genuine duplicates in the link
will not be detected. will not be detected.
A network operator MAY use this mitigation. A Service Provider router such as an access concentrator or network
core router SHOULD support this mitigation strategy.
3.2. Dynamic Disable/Enable of DAD Using Layer 2 Protocol 3.2. Dynamic Disable/Enable of DAD Using Layer 2 Protocol
It is possible that one or more layer 2 protocols include provisions It is possible that one or more layer 2 protocols include provisions
to detect the existence of a loopback on an interface circuit, to detect the existence of a loopback on an interface circuit,
usually by comparing protocol data sent and received. For example, usually by comparing protocol data sent and received. For example,
PPP uses magic number (section 6.4 of [RFC1661]) to detect a loopback PPP uses magic number (section 6.4 of [RFC1661]) to detect a loopback
on an interface. on an interface.
When a layer 2 protocol detects that a loopback is present on an When a layer 2 protocol detects that a loopback is present on an
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