< draft-thubert-6lo-rfc6775-update-reqs-02.txt		draft-thubert-6lo-rfc6775-update-reqs-03.txt >
	6Lo P. Thubert, Ed.		6Lo P. Thubert, Ed.
	Internet-Draft cisco		Internet-Draft cisco
	Intended status: Standards Track August 19, 2014		Intended status: Standards Track August 20, 2014
	Expires: February 18, 2015		Expires: February 19, 2015
	Requirements for an update to 6LoWPAN ND		Requirements for an update to 6LoWPAN ND
	draft-thubert-6lo-rfc6775-update-reqs-02		draft-thubert-6lo-rfc6775-update-reqs-03
	Abstract		Abstract
	Work presented at the 6lo, 6TiSCH and 6MAN working groups suggest		Work presented at the ROLL, 6lo, 6TiSCH and 6MAN Working Groups
	that enhancements to the 6LoWPAN ND mechanism. This document		suggest that enhancements to the 6LoWPAN ND mechanism are now needed.
	elaborates on such requirements.		This document elaborates on those requirements and suggests
			approaches to serve them.
	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 February 18, 2015.		This Internet-Draft will expire on February 19, 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 (http://trustee.ietf.org/		Provisions Relating to IETF Documents (http://trustee.ietf.org/
	license-info) in effect on the date of publication of this document.		license-info) in effect on the date of publication of this document.
	Please review these documents carefully, as they describe your rights		Please review these documents carefully, as they describe your rights
	skipping to change at page 2, line 12 ¶		skipping to change at page 2, line 13 ¶
	3.1. RPL Leaf Support in 6LoWPAN ND . . . . . . . . . . . . . . 5		3.1. RPL Leaf Support in 6LoWPAN ND . . . . . . . . . . . . . . 5
	3.2. registration Failures Due to Movement . . . . . . . . . . 6		3.2. registration Failures Due to Movement . . . . . . . . . . 6
	3.3. Proxy registration . . . . . . . . . . . . . . . . . . . . 6		3.3. Proxy registration . . . . . . . . . . . . . . . . . . . . 6
	3.4. Target Registration . . . . . . . . . . . . . . . . . . . 6		3.4. Target Registration . . . . . . . . . . . . . . . . . . . 6
	3.5. RPL root vs. 6LBR . . . . . . . . . . . . . . . . . . . . 7		3.5. RPL root vs. 6LBR . . . . . . . . . . . . . . . . . . . . 7
	3.6. Securing the Registration . . . . . . . . . . . . . . . . 7		3.6. Securing the Registration . . . . . . . . . . . . . . . . 7
	4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 8		4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 8
	4.1. Requirements Related to Mobility . . . . . . . . . . . . . 8		4.1. Requirements Related to Mobility . . . . . . . . . . . . . 8
	4.2. Requirements Related to Routing Protocols . . . . . . . . 8		4.2. Requirements Related to Routing Protocols . . . . . . . . 8
	4.3. Requirements Related to the Variety of Low-Power Link types 9		4.3. Requirements Related to the Variety of Low-Power Link types 9
	4.4. Requirements Related to Proxy Operations . . . . . . . . . 9		4.4. Requirements Related to Proxy Operations . . . . . . . . . 10
	4.5. Requirements Related to Security . . . . . . . . . . . . . 10		4.5. Requirements Related to Security . . . . . . . . . . . . . 10
	4.6. Requirements Related to Low-Power devices . . . . . . . . 10		4.6. Requirements Related to Low-Power devices . . . . . . . . 10
	5. Suggested Changes to Protocol Elements . . . . . . . . . . . . 10		5. Suggested Changes to Protocol Elements . . . . . . . . . . . . 10
	5.1. ND Neighbor Solicitation (NS) . . . . . . . . . . . . . . 10		5.1. ND Neighbor Solicitation (NS) . . . . . . . . . . . . . . 10
	5.2. ND Router Advertisement (RA) . . . . . . . . . . . . . . . 10		5.2. ND Router Advertisement (RA) . . . . . . . . . . . . . . . 11
	5.3. RPL DODAG Information Object (DIO) . . . . . . . . . . . . 11		5.3. RPL DODAG Information Object (DIO) . . . . . . . . . . . . 11
	5.4. ND Enhanced Address Registration Option (EARO) . . . . . . 11		5.4. ND Enhanced Address Registration Option (EARO) . . . . . . 11
	6. Security Considerations . . . . . . . . . . . . . . . . . . . 12		6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
	7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12		7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
	8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12		8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 13
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12		9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
	9.1. Normative References . . . . . . . . . . . . . . . . . . . 12		9.1. Normative References . . . . . . . . . . . . . . . . . . . 13
	9.2. Informative References . . . . . . . . . . . . . . . . . . 13		9.2. Informative References . . . . . . . . . . . . . . . . . . 14
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 15		Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 15
	1. Introduction		1. Introduction
	A number of use cases, including the Industrial Internet, require a		A number of use cases, including the Industrial Internet, require a
	large scale deployment of sensors that can not be realized with wires		large scale deployment of sensors that can not be realized with wires
	and is only feasible over wireless Low power and Lossy Network (LLN)		and is only feasible over wireless Low power and Lossy Network (LLN)
	technologies. When simpler hub-and-spoke topologies are not		technologies. When simpler hub-and-spoke topologies are not
	sufficient for the expected throughput and density, mesh networks		sufficient for the expected throughput and density, mesh networks
	must be deployed, which implies the concepts of hosts and routers,		must be deployed, which implies the concepts of hosts and routers,
	skipping to change at page 3, line 15 ¶		skipping to change at page 3, line 15 ¶
	At the same time, new work at 6MAN on Efficiency aware IPv6 Neighbor		At the same time, new work at 6MAN on Efficiency aware IPv6 Neighbor
	Discovery Optimizations [I-D.chakrabarti-nordmark-6man-efficient-nd]		Discovery Optimizations [I-D.chakrabarti-nordmark-6man-efficient-nd]
	suggests that 6LoWPAN ND can be extended to other types of networks		suggests that 6LoWPAN ND can be extended to other types of networks
	on top of the Low power and Lossy Networks (LLNs) for which it was		on top of the Low power and Lossy Networks (LLNs) for which it was
	already defined. The value of such extension is especially apparent		already defined. The value of such extension is especially apparent
	in the case of mobile wireless devices, to reduce the multicast		in the case of mobile wireless devices, to reduce the multicast
	operations that are related to classical ND ([RFC4861], [RFC4862])		operations that are related to classical ND ([RFC4861], [RFC4862])
	and plague the wireless medium. In this context also, there is a		and plague the wireless medium. In this context also, there is a
	need for additions to the protocol.		need for additions to the protocol.
	The"Optimistic Duplicate Address Detection" [RFC4429](ODAD)		The Optimistic Duplicate Address Detection [RFC4429] (ODAD)
	specification details how an address can be used before a Duplicate		specification details how an address can be used before a Duplicate
	Address Detection (DAD) is complete, and insists that an address that		Address Detection (DAD) is complete, and insists that an address that
	is TENTATIVE should not be associated to a Source Link-Layer Address		is TENTATIVE should not be associated to a Source Link-Layer Address
	Option in a Neighbor Solicitation message. As we expect the 6LoWPAN		Option in a Neighbor Solicitation message. As we expect the 6LoWPAN
	ND protocol for a more general use, it can make sense to keep		ND protocol for a more general use, it can make sense to keep
	respecting that rule, which is another change to the specification.		respecting that rule, which is another change to the specification.
	This document proposes a limited evolution to [RFC6775] so as to		This document suggests a limited evolution to [RFC6775] so as to
	allow operation of a 6LoWPAN ND node as a leaf to a RPL network, and		allow operation of a 6LoWPAN ND node as a leaf in a RPL network. It
	enable a more generalized use of the formats therein outside of the		also suggests a more generalized use of the information in the ARO
	strict LLN domain.		option outside of the strict LLN domain, for instance over a
			converged backbone.
	2. Terminology		2. Terminology
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in [RFC2119].		document are to be interpreted as described in [RFC2119].
	Readers are expected to be familiar with all the terms and concepts		Readers are expected to be familiar with all the terms and concepts
	that are discussed in "Neighbor Discovery for IP version 6"		that are discussed in "Neighbor Discovery for IP version 6"
	[RFC4861], "IPv6 Stateless Address Autoconfiguration" [RFC4862],		[RFC4861], "IPv6 Stateless Address Autoconfiguration" [RFC4862],
	skipping to change at page 4, line 15 ¶		skipping to change at page 4, line 15 ¶
	sequence number that is used to track the movements of the device,		sequence number that is used to track the movements of the device,
	and optionally some information about the RPL topology that this		and optionally some information about the RPL topology that this
	device will join.		device will join.
	The scope of the 6TiSCH Architecture is a Backbone Link that		The scope of the 6TiSCH Architecture is a Backbone Link that
	federates multiple LLNs as a single IPv6 Multi-Link Subnet. Each LLN		federates multiple LLNs as a single IPv6 Multi-Link Subnet. Each LLN
	in the subnet is anchored at a Backbone Router (6BBR). The Backbone		in the subnet is anchored at a Backbone Router (6BBR). The Backbone
	Routers interconnect the LLNs over the Backbone Link and emulate that		Routers interconnect the LLNs over the Backbone Link and emulate that
	the LLN nodes are present on the Backbone by proxy-ND operations. An		the LLN nodes are present on the Backbone by proxy-ND operations. An
	LLN node can move freely from an LLN Route-Over mesh anchored at a		LLN node can move freely from an LLN Route-Over mesh anchored at a
	Backbone Router to another anchored at same or a different Backbone		Backbone Router to another anchored at a same or a different Backbone
	Router inside the Multi-Link Subnet and conserve its addresses.		Router inside the Multi-Link Subnet and conserve its addresses.
	---+------------------------		---+------------------------
	| Plant Network		| Plant Network
	|		|
	+-----+		+-----+
	| | Gateway		| | Gateway
	| |		| |
	+-----+		+-----+
	|		|
	skipping to change at page 4, line 42 ¶		skipping to change at page 4, line 42 ¶
	+-----+ +-----+ +-----+		+-----+ +-----+ +-----+
	| | | | | |		| | | | | |
	0 0 0 0 0 (6LBR == RPL root)		0 0 0 0 0 (6LBR == RPL root)
	o o o o o o o o o o o o o o		o o o o o o o o o o o o o o
	o o o o o o o o o o (6LR == RPL router)		o o o o o o o o o o (6LR == RPL router)
	o o o o o o o z		o o o o o o o z
	o o o o o z		o o o o o z
	RPL Instances (6LoWPAN Host == RPL leaf)		RPL Instances (6LoWPAN Host == RPL leaf)
	The root of the RPL topology is logically separated from the 6BBR		The root of the RPL topology is logically separated from the 6BBR
	that is used to connect the RPL topology to the backbone. Efficient		that is used to connect the RPL topology to the backbone. The RPL
	ND is a perfect interface for the RPL root to register the LLN node		root can use Efficient ND as the interface to register an LLN node in
	in its topology to the 6BBR for proxy operations. It results that		its topology to the 6BBR for whatever operation the 6BBR performs,
	the signalling would start at the leaf node with 6LoWPAN ND, then		such as ND proxy operations, or injection in a routing protocol. It
	would be carried over RPL to the RPL root, and then with Efficient-ND		results that, as illustrated in Figure 2, the periodic signaling
	to the 6BBR. Efficient ND being an adaptation of 6LoWPAN ND, it		could start at the leaf node with 6LoWPAN ND, then would be carried
	makes sense to keep those two homogeneous in the way they use the		over RPL to the RPL root, and then with Efficient-ND to the 6BBR.
	source and the target addresses in the Neighbor Solicitation (NS)
	messages for registration, as well as in the options that they use		Efficient ND being an adaptation of 6LoWPAN ND, it makes sense to
	for that process.		keep those two homogeneous in the way they use the source and the
			target addresses in the Neighbor Solicitation (NS) messages for
			registration, as well as in the options that they use for that
			process.
	6LoWPAN Node 6LR 6LBR 6BBR		6LoWPAN Node 6LR 6LBR 6BBR
	(RPL leaf) (router) (root)		(RPL leaf) (router) (root)
	| | | |		| | | |
	| 6LoWPAN ND |6LoWPAN ND+RPL | Efficient ND | IPv6 ND		| 6LoWPAN ND |6LoWPAN ND+RPL | Efficient ND | IPv6 ND
	| LLN link |Route-Over mesh| IPv6 link | Backbone		| LLN link |Route-Over mesh| IPv6 link | Backbone
	| | | |		| | | |
	| NS(ARO) | | |		| NS(ARO) | | |
	|-------------->| | |		|-------------->| | |
	| 6LoWPAN ND | DAR (then DAO)| |		| 6LoWPAN ND | DAR (then DAO)| |
	| |-------------->| |		| |-------------->| |
	| | | NS(ARO) |		| | | NS(ARO) |
	| | |-------------->|		| | |-------------->|
	| | | | DAD		| | | | DAD
	| | | |------>		| | | |------>
	| | | |		| | | |
	| | | NA(ARO) |		| | | NA(ARO) |
	| | |<--------------|		| | |<--------------|
	| | DAC | |		| | DAC | |
	| |<--------------| | |		| |<--------------| |
	| NA(ARO) | | |		| NA(ARO) | | |
	|<--------------| | | |		|<--------------| | |
	As the network builds up, a node should start as a leaf to join the		As the network builds up, a node should start as a leaf to join the
	RPL network, and may later turn into a RPL router and eventually a		RPL network, and may later turn into both a RPL-capable router and a
	6LR as well, so as to accept leaf nodes to recursively join the		6LR, so as to accept leaf nodes to recursively join the network.
	network.
	3.1. RPL Leaf Support in 6LoWPAN ND		3.1. RPL Leaf Support in 6LoWPAN ND
	RPL needs a set of information in order to advertise a leaf node		RPL needs a set of information in order to advertise a leaf node
	through a DAO message and establish reachability.		through a DAO message and establish reachability.
	At the bare minimum the leaf device must provide a sequence number		At the bare minimum the leaf device must provide a sequence number
	that matches the RPL specification in section 7. [I-D.chakrabarti-		that matches the RPL specification in section 7. [I-D.chakrabarti-
	nordmark-6man-efficient-nd] section "4.1. Address Registration		nordmark-6man-efficient-nd] section "4.1. Address Registration
	Option" (ARO) already incorporates that addition with a new field in		Option" (ARO) already incorporates that addition with a new field in
	skipping to change at page 7, line 48 ¶		skipping to change at page 7, line 48 ¶
	for itself or on behalf of LLN nodes.		for itself or on behalf of LLN nodes.
	3.5. RPL root vs. 6LBR		3.5. RPL root vs. 6LBR
	6LoWPAN ND is unclear on how the 6LBR is discovered, and how the		6LoWPAN ND is unclear on how the 6LBR is discovered, and how the
	liveliness of the 6LBR is asserted over time. On the other hand, the		liveliness of the 6LBR is asserted over time. On the other hand, the
	discovery and liveliness of the RPL root are obtained through the RPL		discovery and liveliness of the RPL root are obtained through the RPL
	protocol.		protocol.
	When 6LoWPAN ND is coupled with RPL, it makes sense to collocate the		When 6LoWPAN ND is coupled with RPL, it makes sense to collocate the
	6LBR functionality and that of the RPL root. The DAR/DAC exchange		6LBR and the RPL root functionalities. The DAR/DAC exchange becomes
	becomes a preamble to the DAO messages that are used from then on to		a preamble to the DAO messages that are used from then on to
	reconfirm the registration, thus eliminating a duplication of		reconfirm the registration, thus eliminating a duplication of
	functionality between DAO and DAR messages.		functionality between DAO and DAR messages.
	3.6. Securing the Registration		3.6. Securing the Registration
	A typical attack against IPv6 ND is address spoofing, whereby a rogue		A typical attack against IPv6 ND is address spoofing, whereby a rogue
	node claims the IPv6 Address of another node in and hijacks its		node claims the IPv6 Address of another node in and hijacks its
	traffic.		traffic.
	SEcure Neighbor Discovery (SEND) [RFC3971] is designed to protect		SEcure Neighbor Discovery (SEND) [RFC3971] is designed to protect
	each individual ND lookup/advertisement in a peer to peer model where		each individual ND lookup/advertisement in a peer to peer model where
	skipping to change at page 8, line 32 ¶		skipping to change at page 8, line 32 ¶
	should thus be possible to protect the ownership of all the addresses		should thus be possible to protect the ownership of all the addresses
	of a 6LoWPAN Node with a single key, and there should not be a need		of a 6LoWPAN Node with a single key, and there should not be a need
	to carry the cryptographic material more than once to the 6LBR.		to carry the cryptographic material more than once to the 6LBR.
	4. Requirements		4. Requirements
	4.1. Requirements Related to Mobility		4.1. Requirements Related to Mobility
	Due to the nature of LLN networks, even a fixed 6LoWPAN Node may		Due to the nature of LLN networks, even a fixed 6LoWPAN Node may
	change its point of attachment (a 6LR) and may not be able to notify		change its point of attachment (a 6LR) and may not be able to notify
	the previous 6LR that it has disconnected. It results that the		the 6LR that it has disconnected from. It results that the previous
	previous 6LR may still attract traffic that it cannot deliver. When		6LR may still attract traffic that it cannot deliver any more. When
	the 6LR changes, there is thus a need to identify stale states and		the 6LR changes, there is thus a need to identify stale states and
	restore reachability timely.		restore reachability timely.
	Upon a change of point of attachment, connectivity via a new 6LR MUST		Req1.1: Upon a change of point of attachment, connectivity via a new
	be restored timely without the need to de-register from the previous		6LR MUST be restored timely without the need to de-register from the
	6LR.		previous 6LR.
	For that purpose, the protocol MUST enable to differentiate multiple		Req1.2: For that purpose, the protocol MUST enable to differentiate
	registrations from a same 6LoWPAN Node from two different 6LoWPAN		multiple registrations from a same 6LoWPAN Node from two different
	Nodes claiming a same address.		6LoWPAN Nodes claiming a same address.
	This information MUST be passed from the 6LR to the 6LBR, and the		Req1.3: This information MUST be passed from the 6LR to the 6LBR, and
	6LBR SHOULD be able to clean up the stale state asynchronously in the		the 6LBR SHOULD be able to clean up the stale state asynchronously in
	previous 6LR.		the previous 6LR.
	A 6LoWPAN Node SHOULD also be capable to register a same Address to		Req1.4: A 6LoWPAN Node SHOULD also be capable to register a same
	multiple 6LRs, and this, concurrently.		Address to multiple 6LRs, and this, concurrently.
	4.2. Requirements Related to Routing Protocols		4.2. Requirements Related to Routing Protocols
	The point of attachment of a 6LoWPAN Node may be a 6LR in an LLN		The point of attachment of a 6LoWPAN Node may be a 6LR in an LLN
	mesh. An LLN route-over mesh is typically based on RPL, which is the		mesh. An LLN route-over mesh is typically based on RPL, which is the
	routing protocol that was defined at the IETF for this particular		routing protocol that was defined at the IETF for this particular
	purpose. It derives that in this scenario, the 6LR would classically		purpose. It derives that in this scenario, the 6LR would classically
	support RPL. One goal is that a 6LoWPAN Node attached via ND to a		support RPL. One goal is that a 6LoWPAN Node attached via ND to a
	RPL-capable 6LR would not need to participate to the RPL protocol to		RPL-capable 6LR would not need to participate to the RPL protocol to
	obtain reachability via the 6LR. An additional goal would be to		obtain reachability via the 6LR. An additional goal would be to
	obtain reachability via other routing protocols through a same ND-		obtain reachability via other routing protocols through a same ND-
	based abstraction.		based abstraction.
	The ND registration method SHOULD be extended in such a fashion that		Related requirements are:
	the 6LR MAY advertise the Address of a 6LoWPAN Node over RPL and
	obtain reachability to that Address over the RPL domain.
	The Address Registration Option used in the ND registration SHOULD be		Req2.1: The ND registration method SHOULD be extended in such a
	extended to carry enough information to generate a DAO message as		fashion that the 6LR MAY advertise the Address of a 6LoWPAN Node over
	specified in [RFC6550] section 6.4, in particular the capability to		RPL and obtain reachability to that Address over the RPL domain.
	compute a DAOSequence and, as an option, a RPLInstanceID.
	Depending on their applicability to LLNs, other RPLInstanceID mesh/		Req2.2: The Address Registration Option that is used in the ND
	MANET protocols MAY be considered as well.		registration SHOULD be extended to carry enough information to
			generate a DAO message as specified in [RFC6550] section 6.4, in
			particular the capability to compute a DAOSequence and, as an option,
			a RPLInstanceID.
			Req2.3: Depending on their applicability to LLNs, other standard mesh
			/MANET protocols MAY be considered as well.
	4.3. Requirements Related to the Variety of Low-Power Link types		4.3. Requirements Related to the Variety of Low-Power Link types
	6LoWPAN ND [RFC6775] was defined with a focus on IEEE802.15.4 and in		6LoWPAN ND [RFC6775] was defined with a focus on IEEE802.15.4 and in
	particular the capability to derive a unique Identifier from a		particular the capability to derive a unique Identifier from a
	globally unique MAC-64 address. At this point, the 6lo Working Group		globally unique MAC-64 address. At this point, the 6lo Working Group
	is extending the 6LoWPAN Header Compression (HC) [RFC6282] technique		is extending the 6LoWPAN Header Compression (HC) [RFC6282] technique
	to other link types ITU-T G.9959 [I-D.brandt-6man-lowpanz], Master-		to other link types ITU-T G.9959 [I-D.brandt-6man-lowpanz], Master-
	Slave/Token-Passing [I-D.ietf-6man-6lobac], DECT Ultra Low Energy		Slave/Token-Passing [I-D.ietf-6man-6lobac], DECT Ultra Low Energy
	[I-D.mariager-6lowpan-v6over-dect-ule], Near Field Communication [I-D		[I-D.mariager-6lowpan-v6over-dect-ule], Near Field Communication [I-D
	.hong-6lo-ipv6-over-nfc], as well as IEEE1901.2 Narrowband Powerline		.hong-6lo-ipv6-over-nfc], as well as IEEE1901.2 Narrowband Powerline
	Communication Networks [I-D.popa-6lo-6loplc-ipv6-over-		Communication Networks [I-D.popa-6lo-6loplc-ipv6-over-
	ieee19012-networks] and BLUETOOTH(R) Low Energy [I-D.ietf-6lo-btle].		ieee19012-networks] and BLUETOOTH(R) Low Energy [I-D.ietf-6lo-btle].
	The support of the registration mechanism SHOULD be extended to more		Related requirements are:
	LLN links, matching at least the links that are considered by 6lo as
	well as other RPLInstanceID Low-Power links such as Low-Power Wi-Fi.
	As part of this extension, a mechanism to compute a unique Identifier		Req3.1: The support of the registration mechanism SHOULD be extended
	should be provided, with the capability to form a Link-Local Address		to more LLN links, matching at least the links that are considered by
	that can not be a duplicate. The Identifier SHOULD be unique at		6lo as well as other popular Low-Power links such as Low-Power Wi-Fi.
	least to the domain where an Address formed by this device may be
	advertised through ND mechanisms.
	The Address Registration Option used in the ND registration SHOULD be		Req3.2: As part of this extension, a mechanism to compute a unique
	extended to carry the relevant forms of unique Identifier.		Identifier should be provided, with the capability to form a Link-
			Local Address that can not be a duplicate. The Identifier SHOULD be
			unique at least to the domain where an Address formed by this device
			may be advertised through ND mechanisms.
			Req3.3: The Address Registration Option used in the ND registration
			SHOULD be extended to carry the relevant forms of unique Identifier.
	4.4. Requirements Related to Proxy Operations		4.4. Requirements Related to Proxy Operations
	The registration mechanism SHOULD enable a third party to proxy		Sleeping devices may not be able to answer themselves to a lookup
	register an Address on behalf of a 6LoWPAN node that may be sleeping		from a node that uses classical ND on a backbone and may need a proxy
	or located deeper in an LLN mesh.		operation by a 6BBR. Additionally, the device may need to rely on the
			6LBR to perform that registration to the 6BBR.
			Related requirements are:
			Req4.1: The registration mechanism SHOULD enable a third party to
			proxy register an Address on behalf of a 6LoWPAN node that may be
			sleeping or located deeper in an LLN mesh.
	4.5. Requirements Related to Security		4.5. Requirements Related to Security
	In order to guarantee the operations of the 6LoWPAN ND flows, the		In order to guarantee the operations of the 6LoWPAN ND flows, the
	spoofing of the 6LR, 6LBR and 6BBRs roles should be avoided. Once a		spoofing of the 6LR, 6LBR and 6BBRs roles should be avoided. Once a
	node successfully registers an address, 6LoWPAN ND should provide the		node successfully registers an address, 6LoWPAN ND should provide the
	means to protect that ownership even if the node is sleeping. In		means to protect that ownership even if the node is sleeping. In
	particular, the 6LR and the 6LBR then should be able to verify		particular, the 6LR and the 6LBR then should be able to verify
	whether a subsequent registration for a same Address comes from a		whether a subsequent registration for a same Address comes from a
	same node or is a duplicate.		same node or is a duplicate.
	6LoWPAN ND SHOULD provide a mechanism for the 6LR, 6LBR and 6BBR to		Related requirements are:
	authenticate and authorize one another for their respective roles, as
	well as with the 6LoWPAN Node for the role of 6LR.
	6LoWPAN ND SHOULD provide a mechanism for the 6LR and the 6LBR to		Req5.1: 6LoWPAN ND SHOULD provide a mechanism for the 6LR, 6LBR and
	validate whether a new registration corresponds to a same 6LoWPAN		6BBR to authenticate and authorize one another for their respective
	Node, and, if not, determine the rightful owner, and deny or clean-up		roles, as well as with the 6LoWPAN Node for the role of 6LR.
	the registration that is deemed in excess.
			Req5.2: 6LoWPAN ND SHOULD provide a mechanism for the 6LR and the
			6LBR to validate whether a new registration corresponds to a same
			6LoWPAN Node, and, if not, determine the rightful owner, and deny or
			clean-up the registration that is deemed in excess.
	4.6. Requirements Related to Low-Power devices		4.6. Requirements Related to Low-Power devices
	The ND registration method is designed to save energy on Low-Power		The ND registration method is designed to save energy on Low-Power
	devices, and in particular enable duty-cycled devices that are		devices, and in particular enable duty-cycled devices that are
	sleeping most of the time and not capable to defend their own		sleeping most of the time and not capable to defend their own
	Addresses against always-on devices.		Addresses against always-on devices.
	The registration mechanism SHOULD be applicable to a Low-Power device		Related requirements are:
	regardless of the link type, and enable a 6BBR to operate as a proxy
	to defend the registered Addresses on its behalf.		Req6.1: The registration mechanism SHOULD be applicable to a Low-
			Power device regardless of the link type, and enable a 6BBR to
			operate as a proxy to defend the registered Addresses on its behalf.
	5. Suggested Changes to Protocol Elements		5. Suggested Changes to Protocol Elements
	5.1. ND Neighbor Solicitation (NS)		5.1. ND Neighbor Solicitation (NS)
	The NS message used for registration should use a source address that		The NS message used for registration should use a source address that
	respects the rules in [RFC6775], [RFC4861], and [RFC4429] for DAD.		respects the rules in [RFC6775], [RFC4861], and [RFC4429] for DAD.
	The SLLA Option may be present but only if the address passed DAD,		The SLLA Option may be present but only if the address passed DAD,
	and it is used to allow the 6LR to respond as opposed to as a		and it is used to allow the 6LR to respond as opposed to as a
	registration mechanism.		registration mechanism.
	The address that is being registered is the target address in the NS		The address that is being registered is the target address in the NS
	message and the TLLA Option must be present.		message and the TLLA Option must be present.
	5.2. ND Router Advertisement (RA)		5.2. ND Router Advertisement (RA)
	skipping to change at page 11, line 28 ¶		skipping to change at page 11, line 43 ¶
	prefix lifetime.		prefix lifetime.
	5.3. RPL DODAG Information Object (DIO)		5.3. RPL DODAG Information Object (DIO)
	If the RPL root serves as 6LBR, it makes sense to add at least a bit		If the RPL root serves as 6LBR, it makes sense to add at least a bit
	of information in the DIO to signal so. A Registrar Address Option		of information in the DIO to signal so. A Registrar Address Option
	(RAO) may also be considered for addition.		(RAO) may also be considered for addition.
	5.4. ND Enhanced Address Registration Option (EARO)		5.4. ND Enhanced Address Registration Option (EARO)
			The ARO option contains a Unique ID that is supposed to identify the
			device across multiple registrations. It is envisioned that the
			device could form a single CGA-based Unique Interface ID (CUID) to
			securely bind all of its addresses. The CUID would be used as Unique
			Interface Identifier in the ARO option and to form a Link-Local
			address that would be deemed unique regardless of the Link type.
			Provided that the relevant cryptographic material is passed to the
			6LBR upon the first registration or on-demand at a later time, the
			6LBR can validate that a Node is effectively the owner of a CUID, and
			ensure that the ownership of an Address stays with the CUID that
			registered it first.
	This option is designed to be used with standard NS and NA messages		This option is designed to be used with standard NS and NA messages
	between backbone Routers as well as between nodes and 6LRs over the		between backbone Routers as well as between nodes and 6LRs over the
	LLN and between the 6LBR and the 6BBR over whatever IP link they use		LLN and between the 6LBR and the 6BBR over whatever IP link they use
	to communicate.		to communicate.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Type | Length | Status | RPLInstanceID |		| Type | Length | Status | RPLInstanceID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	skipping to change at page 12, line 27 ¶		skipping to change at page 12, line 53 ¶
	should be reset after the DAD operation upon address formation.		should be reset after the DAD operation upon address formation.
	6. Security Considerations		6. Security Considerations
	This specification expects that the link layer is sufficiently		This specification expects that the link layer is sufficiently
	protected, either by means of physical or IP security for the		protected, either by means of physical or IP security for the
	Backbone Link or MAC sublayer cryptography. In particular, it is		Backbone Link or MAC sublayer cryptography. In particular, it is
	expected that the LLN MAC provides secure unicast to/from the		expected that the LLN MAC provides secure unicast to/from the
	Backbone Router and secure broadcast from the Backbone Router in a		Backbone Router and secure broadcast from the Backbone Router in a
	way that prevents tempering with or replaying the RA messages.		way that prevents tempering with or replaying the RA messages.
			Still, Section 4.5 has a requirement for a mutual authentication and
			authorization for a role for 6LRs, 6LBRs and 6BBRs.
	The use of EUI-64 for forming the Interface ID in the link local		This documents also suggests in Section 5.4 that a 6LoWPAN Node could
	address prevents the usage of Secure ND ([RFC3971] and [RFC3972]) and		form a single Unique Interface ID (CUID) based on cryptographic
	address privacy techniques. Considering the envisioned deployments		techniques similar to CGA. The CUID would be used as Unique
	and the MAC layer security applied, this is not considered an issue		Interface Identifier in the ARO option and new Secure ND procedures
	at this time. It is envisioned that the device could form a single		would be proposed to use it as opposed to the source IPv6 address to
	CGA-based Unique Interface ID (CUID) to securely bind all of its		secure the binding between an Address and its owning Node, and
	addresses. The CUID would be used as Unique Interface Identifier in		enforce First/Come-First/Serve at the 6LBR.
	the ARO option and the Secure ND procedures would be changed to use
	it as opposed to the source IPv6 address.
	7. IANA Considerations		7. IANA Considerations
	A new type is requested for an ND option.		A new type is requested for an ND option.
	8. Acknowledgments		8. Acknowledgments
	Samita, Erik, JP, Eric, Thomas, you will all recognize your influence		The author wishes acknowledge the contributions by Samita
	in this work...		Chakrabarti, Erik Normark, JP Vasseur, Eric Levy-Abegnoli, Patrick
			Wetterwald, Thomas Watteyne, and Behcet Sarikaya.
	9. References		9. References
	9.1. Normative References		9.1. Normative References
	[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.
	[RFC2460] Deering, S.E. and R.M. Hinden, "Internet Protocol, Version		[RFC2460] Deering, S.E. and R.M. Hinden, "Internet Protocol, Version
	6 (IPv6) Specification", RFC 2460, December 1998.		6 (IPv6) Specification", RFC 2460, December 1998.
End of changes. 35 change blocks.
	94 lines changed or deleted		126 lines changed or added
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