draft-ietf-6man-enhanced-dad-08.txt		draft-ietf-6man-enhanced-dad-09.txt
	Network Working Group R. Asati		Network Working Group R. Asati
	Internet-Draft H. Singh		Internet-Draft H. Singh
	Updates: 4862, 4861, 3971 (if approved) W. Beebee		Updates: 4862, 4861, 3971 (if approved) W. Beebee
	Intended status: Standards Track C. Pignataro		Intended status: Standards Track C. Pignataro
	Expires: May 14, 2015 Cisco Systems, Inc.		Expires: May 17, 2015 Cisco Systems, Inc.
	E. Dart		E. Dart
	Lawrence Berkeley National Laboratory		Lawrence Berkeley National Laboratory
	W. George		W. George
	Time Warner Cable		Time Warner Cable
	November 10, 2014		November 13, 2014
	Enhanced Duplicate Address Detection		Enhanced Duplicate Address Detection
	draft-ietf-6man-enhanced-dad-08		draft-ietf-6man-enhanced-dad-09
	Abstract		Abstract
	IPv6 Loopback Suppression and Duplicate Address Detection (DAD) are		IPv6 Loopback Suppression and Duplicate Address Detection (DAD) are
	discussed in Appendix A of [RFC4862]. That specification mentions a		discussed in Appendix A of RFC4862. That specification mentions a
	hardware-assisted mechanism to detect looped back DAD messages. If		hardware-assisted mechanism to detect looped back DAD messages. If
	hardware cannot suppress looped back DAD messages, a software		hardware cannot suppress looped back DAD messages, a software
	solution is required. Several service provider communities have		solution is required. Several service provider communities have
	expressed a need for automated detection of looped backed Neighbor		expressed a need for automated detection of looped backed Neighbor
	Discovery (ND) messages used by DAD. This document includes		Discovery (ND) messages used by DAD. This document includes
	mitigation techniques and outlines the Enhanced DAD algorithm to		mitigation techniques and outlines the Enhanced DAD algorithm to
	automate the detection of looped back IPv6 ND messages used by DAD.		automate the detection of looped back IPv6 ND messages used by DAD.
	For network loopback tests, the Enhanced DAD algorithm allows IPv6 to		For network loopback tests, the Enhanced DAD algorithm allows IPv6 to
	self-heal after a loopback is placed and removed. Further, for		self-heal after a loopback is placed and removed. Further, for
	certain access networks the document automates resolving a specific		certain access networks the document automates resolving a specific
	duplicate address conflict.		duplicate address conflict. This document updates RFC4861, RFC4862,
			and RFC3971.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	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 May 14, 2015.		This Internet-Draft will expire on May 17, 2015.
	Copyright Notice		Copyright Notice
	Copyright (c) 2014 IETF Trust and the persons identified as the		Copyright (c) 2014 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
	skipping to change at page 3, line 11		skipping to change at page 3, line 11
	solution is required. One specific DAD message is the Neighbor		solution is required. One specific DAD message is the Neighbor
	Solicitation (NS), specified in [RFC4861]. The NS is issued by the		Solicitation (NS), specified in [RFC4861]. The NS is issued by the
	network interface of an IPv6 node for DAD. Another message involved		network interface of an IPv6 node for DAD. Another message involved
	in DAD is the Neighbor Advertisement (NA). The Enhanced DAD		in DAD is the Neighbor Advertisement (NA). The Enhanced DAD
	algorithm specified in this document focuses on detecting an NS		algorithm specified in this document focuses on detecting an NS
	looped back to the transmitting interface during the DAD operation.		looped back to the transmitting interface during the DAD operation.
	Detecting a looped back NA does not solve the looped back DAD		Detecting a looped back NA does not solve the looped back DAD
	problem. Detection of any other looped back ND messages during the		problem. Detection of any other looped back ND messages during the
	DAD operation is outside the scope of this document. This document		DAD operation is outside the scope of this document. This document
	also includes a section on Mitigation that discusses means already		also includes a section on Mitigation that discusses means already
	available to mitigate the DAD loopback problem.		available to mitigate the DAD loopback problem. This document
			updates RFC4861, RFC4862, and RFC3971.
	1.1. Two Deployment Problems		1.1. Two Deployment Problems
	In each problem articulated below, the IPv6 link-local address DAD		In each problem articulated below, the IPv6 link-local address DAD
	operation fails due to a looped back DAD probe. However, the looped		operation fails due to a looped back DAD probe. However, the looped
	back DAD probe exists for any IPv6 address type including global		back DAD probe exists for any IPv6 address type including global
	addresses.		addresses.
	Recently, service providers have reported a problem with DAD that is		Recently, service providers have reported a problem with DAD that is
	caused by looped back NS messages. The following is a description of		caused by looped back NS messages. The following is a description of
	skipping to change at page 4, line 8		skipping to change at page 4, line 9
	two broadband modems is enabled for IPv6 and the interface issues a		two broadband modems is enabled for IPv6 and the interface issues a
	NS(DAD) message for the IPv6 link-local address. The NS message		NS(DAD) message for the IPv6 link-local address. The NS message
	reaches one modem first and this modem sends the message to the		reaches one modem first and this modem sends the message to the
	network hub which sends the message to the second modem which		network hub which sends the message to the second modem which
	forwards the message back to the access concentrator. The looped		forwards the message back to the access concentrator. The looped
	back NS message causes the network interface on the access		back NS message causes the network interface on the access
	concentrator to be in a DAD-failed state. Such a network interface		concentrator to be in a DAD-failed state. Such a network interface
	typically serves up to a hundred thousand broadband modems causing		typically serves up to a hundred thousand broadband modems causing
	all the modems (and hosts behind the modems) to fail to get IPv6		all the modems (and hosts behind the modems) to fail to get IPv6
	online on the access network. Additionally, it may be tedious for		online on the access network. Additionally, it may be tedious for
	the access concentrator to find out which of the hundred thousand or		the user of the access concentrator to find out which of the hundred
	more homes looped back the DAD message. Clearly there is a need for		thousand or more homes looped back the DAD message. Clearly there is
	automated detection of looped back NS messages during DAD operations		a need for automated detection of looped back NS messages during DAD
	by a node.		operations by a node.
	2. Terminology		2. Terminology
	o DAD-failed state - Duplication Address Detection failure as		o DAD-failed state - Duplication Address Detection failure as
	specified in [RFC4862]. Note even Optimistic DAD as specified in		specified in [RFC4862]. Note even Optimistic DAD as specified in
	[RFC4429] can fail due to a looped back DAD probe. This document		[RFC4429] can fail due to a looped back DAD probe. This document
	covers looped back detection for Optimistic DAD as well.		covers looped back detection for Optimistic DAD as well.
	o Looped back message - also referred to as a reflected message.		o Looped back message - also referred to as a reflected message.
	The message sent by the sender is received by the sender due to		The message sent by the sender is received by the sender due to
	the network or an Upper Layer Protocol on the sender looping the		the network or an Upper Layer Protocol on the sender looping the
	message back.		message back.
	o Loopback - A function in which the router's layer-3 interface (or		o Loopback - A function in which the router's layer-3 interface (or
	the circuit to which the router's interface is connected) is		the circuit to which the router's interface is connected) is
	looped back or connected to itself. Loopback causes packets sent		looped back or connected to itself. Loopback causes packets sent
	by the interface to be received by the interface and results in		by the interface to be received by the interface and results in
	interface unavailability for regular data traffic forwarding. See		interface unavailability for regular data traffic forwarding. See
	more details in section 9.1 of [RFC1583]. The Loopback function		more details in section 9.1 of [RFC2178]. The Loopback function
	is commonly used in an interface context to gain information on		is commonly used in an interface context to gain information on
	the quality of the interface, by employing mechanisms such as		the quality of the interface, by employing mechanisms such as
	ICMPv6 pings and bit-error tests. In a circuit context, this		ICMPv6 pings and bit-error tests. In a circuit context, this
	function is used in wide area environments including optical Dense		function is used in wide area environments including optical Dense
	Wave Division Multiplexing (DWDM) and SONET/SDH for fault		Wave Division Multiplexing (DWDM) and SONET/SDH for fault
	isolation (e.g. by placing a loopback at different geographic		isolation (e.g. by placing a loopback at different geographic
	locations along the path of a wide area circuit to help locate a		locations along the path of a wide area circuit to help locate a
	circuit fault). The Loopback function may be employed locally or		circuit fault). The Loopback function may be employed locally or
	remotely.		remotely.
	skipping to change at page 10, line 44		skipping to change at page 10, line 44
	Thanks (in alphabetical order by first name) to Bernie Volz, Dmitry		Thanks (in alphabetical order by first name) to Bernie Volz, Dmitry
	Anipko, Eric Levy-Abegnoli, Eric Vyncke, Erik Nordmark, Fred Templin,		Anipko, Eric Levy-Abegnoli, Eric Vyncke, Erik Nordmark, Fred Templin,
	Jouni Korhonen, Michael Sinatra, Ole Troan, Pascal Thubert, Ray		Jouni Korhonen, Michael Sinatra, Ole Troan, Pascal Thubert, Ray
	Hunter, Suresh Krishnan, and Tassos Chatzithomaoglou for their		Hunter, Suresh Krishnan, and Tassos Chatzithomaoglou for their
	guidance and review of the document. Thanks to Thomas Narten for		guidance and review of the document. Thanks to Thomas Narten for
	encouraging this work. Thanks to Steinar Haug and Scott Beuker for		encouraging this work. Thanks to Steinar Haug and Scott Beuker for
	describing the use cases.		describing the use cases.
	9. Normative References		9. Normative References
	[RFC1583] Moy, J., "OSPF Version 2", RFC 1583, March 1994.
	[RFC1661] Simpson, W., "The Point-to-Point Protocol (PPP)", STD 51,		[RFC1661] Simpson, W., "The Point-to-Point Protocol (PPP)", STD 51,
	RFC 1661, July 1994.		RFC 1661, July 1994.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119, March 1997.		Requirement Levels", BCP 14, RFC 2119, March 1997.
			[RFC2178] Moy, J., "OSPF Version 2", RFC 2178, July 1997.
	[RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure		[RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
	Neighbor Discovery (SEND)", RFC 3971, March 2005.		Neighbor Discovery (SEND)", RFC 3971, March 2005.
	[RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD)		[RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD)
	for IPv6", RFC 4429, April 2006.		for IPv6", RFC 4429, April 2006.
	[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,		[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
	"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,		"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
	September 2007.		September 2007.
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