< draft-ietf-6lo-nfc-09.txt		draft-ietf-6lo-nfc-10.txt >
	6Lo Working Group Y. Choi, Ed.		6Lo Working Group Y. Choi, Ed.
	Internet-Draft Y-G. Hong		Internet-Draft Y-G. Hong
	Intended status: Standards Track ETRI		Intended status: Standards Track ETRI
	Expires: July 12, 2018 J-S. Youn		Expires: January 18, 2019 J-S. Youn
	Dongeui Univ		Dongeui Univ
	D-K. Kim		D-K. Kim
	KNU		KNU
	J-H. Choi		J-H. Choi
	Samsung Electronics Co.,		Samsung Electronics Co.,
	January 8, 2018		July 17, 2018
	Transmission of IPv6 Packets over Near Field Communication		Transmission of IPv6 Packets over Near Field Communication
	draft-ietf-6lo-nfc-09		draft-ietf-6lo-nfc-10
	Abstract		Abstract
	Near field communication (NFC) is a set of standards for smartphones		Near field communication (NFC) is a set of standards for smartphones
	and portable devices to establish radio communication with each other		and portable devices to establish radio communication with each other
	by touching them together or bringing them into proximity, usually no		by touching them together or bringing them into proximity, usually no
	more than 10 cm. NFC standards cover communications protocols and		more than 10 cm. NFC standards cover communications protocols and
	data exchange formats, and are based on existing radio-frequency		data exchange formats, and are based on existing radio-frequency
	identification (RFID) standards including ISO/IEC 14443 and FeliCa.		identification (RFID) standards including ISO/IEC 14443 and FeliCa.
	The standards include ISO/IEC 18092 and those defined by the NFC		The standards include ISO/IEC 18092 and those defined by the NFC
	skipping to change at page 1, line 46 ¶		skipping to change at page 1, line 46 ¶
	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 https://datatracker.ietf.org/drafts/current/.		Drafts is at https://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 July 12, 2018.		This Internet-Draft will expire on January 18, 2019.
	Copyright Notice		Copyright Notice
	Copyright (c) 2018 IETF Trust and the persons identified as the		Copyright (c) 2018 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
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://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 2, line 31 ¶		skipping to change at page 2, line 31 ¶
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Conventions and Terminology . . . . . . . . . . . . . . . . . 3		2. Conventions and Terminology . . . . . . . . . . . . . . . . . 3
	3. Overview of Near Field Communication Technology . . . . . . . 4		3. Overview of Near Field Communication Technology . . . . . . . 4
	3.1. Peer-to-peer Mode of NFC . . . . . . . . . . . . . . . . 4		3.1. Peer-to-peer Mode of NFC . . . . . . . . . . . . . . . . 4
	3.2. Protocol Stacks of NFC . . . . . . . . . . . . . . . . . 4		3.2. Protocol Stacks of NFC . . . . . . . . . . . . . . . . . 4
	3.3. NFC-enabled Device Addressing . . . . . . . . . . . . . . 6		3.3. NFC-enabled Device Addressing . . . . . . . . . . . . . . 6
	3.4. MTU of NFC Link Layer . . . . . . . . . . . . . . . . . . 6		3.4. MTU of NFC Link Layer . . . . . . . . . . . . . . . . . . 6
	4. Specification of IPv6 over NFC . . . . . . . . . . . . . . . 7		4. Specification of IPv6 over NFC . . . . . . . . . . . . . . . 7
	4.1. Protocol Stacks . . . . . . . . . . . . . . . . . . . . . 7		4.1. Protocol Stacks . . . . . . . . . . . . . . . . . . . . . 7
	4.2. Link Model . . . . . . . . . . . . . . . . . . . . . . . 7		4.2. Link Model . . . . . . . . . . . . . . . . . . . . . . . 8
	4.3. Stateless Address Autoconfiguration . . . . . . . . . . . 8		4.3. Stateless Address Autoconfiguration . . . . . . . . . . . 9
	4.4. IPv6 Link Local Address . . . . . . . . . . . . . . . . . 9		4.4. IPv6 Link Local Address . . . . . . . . . . . . . . . . . 9
	4.5. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 9		4.5. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 10
	4.6. Dispatch Header . . . . . . . . . . . . . . . . . . . . . 10		4.6. Dispatch Header . . . . . . . . . . . . . . . . . . . . . 11
	4.7. Header Compression . . . . . . . . . . . . . . . . . . . 10		4.7. Header Compression . . . . . . . . . . . . . . . . . . . 11
	4.8. Fragmentation and Reassembly . . . . . . . . . . . . . . 11		4.8. Fragmentation and Reassembly . . . . . . . . . . . . . . 12
	4.9. Unicast Address Mapping . . . . . . . . . . . . . . . . . 11		4.9. Unicast and Multicast Address Mapping . . . . . . . . . . 12
	4.10. Multicast Address Mapping . . . . . . . . . . . . . . . . 12
	5. Internet Connectivity Scenarios . . . . . . . . . . . . . . . 13		5. Internet Connectivity Scenarios . . . . . . . . . . . . . . . 13
	5.1. NFC-enabled Device Connected to the Internet . . . . . . 13		5.1. NFC-enabled Device Connected to the Internet . . . . . . 13
	5.2. Isolated NFC-enabled Device Network . . . . . . . . . . . 13		5.2. Isolated NFC-enabled Device Network . . . . . . . . . . . 14
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14		6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
	7. Security Considerations . . . . . . . . . . . . . . . . . . . 14		7. Security Considerations . . . . . . . . . . . . . . . . . . . 14
	8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14		8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . 15		9. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
	9.1. Normative References . . . . . . . . . . . . . . . . . . 15		9.1. Normative References . . . . . . . . . . . . . . . . . . 15
	9.2. Informative References . . . . . . . . . . . . . . . . . 16		9.2. Informative References . . . . . . . . . . . . . . . . . 17
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
	1. Introduction		1. Introduction
	NFC is a set of short-range wireless technologies, typically		NFC is a set of short-range wireless technologies, typically
	requiring a distance of 10 cm or less. NFC operates at 13.56 MHz on		requiring a distance of 10 cm or less. NFC operates at 13.56 MHz on
	ISO/IEC 18000-3 air interface and at rates ranging from 106 kbit/s to		ISO/IEC 18000-3 air interface and at rates ranging from 106 kbit/s to
	424 kbit/s. NFC always involves an initiator and a target; the		424 kbit/s. NFC always involves an initiator and a target; the
	initiator actively generates an RF field that can power a passive		initiator actively generates an RF field that can power a passive
	target. This enables NFC targets to take very simple form factors		target. This enables NFC targets to take very simple form factors
	such as tags, stickers, key fobs, or cards that do not require		such as tags, stickers, key fobs, or cards that do not require
	skipping to change at page 3, line 50 ¶		skipping to change at page 3, line 50 ¶
	[RFC4944] specifies the transmission of IPv6 over IEEE 802.15.4. The		[RFC4944] specifies the transmission of IPv6 over IEEE 802.15.4. The
	NFC link also has similar characteristics to that of IEEE 802.15.4.		NFC link also has similar characteristics to that of IEEE 802.15.4.
	Many of the mechanisms defined in [RFC4944] can be applied to the		Many of the mechanisms defined in [RFC4944] can be applied to the
	transmission of IPv6 on NFC links. This document specifies the		transmission of IPv6 on NFC links. This document specifies the
	details of IPv6 transmission over NFC links.		details of IPv6 transmission over NFC links.
	2. Conventions and Terminology		2. Conventions and 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", "NOT RECOMMENDED", "MAY", and
	document are to be interpreted as described in [RFC2119].		"OPTIONAL" in this document are to be interpreted as described in BCP
			14 [RFC2119] [RFC8174] when, and only when, they appear in all
			capitals, as shown here.
	3. Overview of Near Field Communication Technology		3. Overview of Near Field Communication Technology
	NFC technology enables simple and safe two-way interactions between		NFC technology enables simple and safe two-way interactions between
	electronic devices, allowing consumers to perform contactless		electronic devices, allowing consumers to perform contactless
	transactions, access digital content, and connect electronic devices		transactions, access digital content, and connect electronic devices
	with a single touch. NFC complements many popular consumer level		with a single touch. NFC complements many popular consumer level
	wireless technologies, by utilizing the key elements in existing		wireless technologies, by utilizing the key elements in existing
	standards for contactless card technology (ISO/IEC 14443 A&B and		standards for contactless card technology (ISO/IEC 14443 A&B and
	JIS-X 6319-4). NFC can be compatible with existing contactless card		JIS-X 6319-4). NFC can be compatible with existing contactless card
	skipping to change at page 4, line 47 ¶		skipping to change at page 4, line 49 ¶
	IPv6 packets to any corresponding node on the Internet when an NFC-		IPv6 packets to any corresponding node on the Internet when an NFC-
	enabled gateway is linked to the Internet.		enabled gateway is linked to the Internet.
	3.2. Protocol Stacks of NFC		3.2. Protocol Stacks of NFC
	IP can use the services provided by the Logical Link Control Protocol		IP can use the services provided by the Logical Link Control Protocol
	(LLCP) in the NFC stack to provide reliable, two-way transport of		(LLCP) in the NFC stack to provide reliable, two-way transport of
	information between the peer devices. Figure 1 depicts the NFC P2P		information between the peer devices. Figure 1 depicts the NFC P2P
	protocol stack with IPv6 bindings to LLCP.		protocol stack with IPv6 bindings to LLCP.
	For data communication in IPv6 over NFC, an IPv6 packet SHALL be		For data communication in IPv6 over NFC, an IPv6 packet MUST be
	passed down to LLCP of NFC and transported to an Information Field in		passed down to LLCP of NFC and transported to an Information Field in
	Protocol Data Unit (I PDU) of LLCP of the NFC-enabled peer device.		Protocol Data Unit (I PDU) of LLCP of the NFC-enabled peer device.
	LLCP does not support fragmentation and reassembly. For IPv6		LLCP does not support fragmentation and reassembly. For IPv6
	addressing or address configuration, LLCP SHALL provide related		addressing or address configuration, LLCP MUST provide related
	information, such as link layer addresses, to its upper layer. The		information, such as link layer addresses, to its upper layer. The
	LLCP to IPv6 protocol binding SHALL transfer the SSAP and DSAP value		LLCP to IPv6 protocol binding MUST transfer the SSAP and DSAP value
	to the IPv6 over NFC protocol. SSAP stands for Source Service Access		to the IPv6 over NFC protocol. SSAP stands for Source Service Access
	Point, which is a 6-bit value meaning a kind of Logical Link Control		Point, which is a 6-bit value meaning a kind of Logical Link Control
	(LLC) address, while DSAP means an LLC address of the destination		(LLC) address, while DSAP means an LLC address of the destination
	NFC-enabled device.		NFC-enabled device.
	| |		| |
	| | Application Layer		| | Application Layer
	| Upper Layer Protocols | Transport Layer		| Upper Layer Protocols | Transport Layer
	| | Network Layer		| | Network Layer
	| | |		| | |
	skipping to change at page 6, line 25 ¶		skipping to change at page 6, line 25 ¶
	service access points, which are defined in the NFC Forum Assigned		service access points, which are defined in the NFC Forum Assigned
	Numbers Register. Address values between 10h and 1Fh SHALL be		Numbers Register. Address values between 10h and 1Fh SHALL be
	assigned by the local LLC to services registered by local service		assigned by the local LLC to services registered by local service
	environment. In addition, address values between 20h and 3Fh SHALL		environment. In addition, address values between 20h and 3Fh SHALL
	be assigned by the local LLC as a result of an upper layer service		be assigned by the local LLC as a result of an upper layer service
	request. Therefore, the address values between 20h and 3Fh can be		request. Therefore, the address values between 20h and 3Fh can be
	used for generating IPv6 interface identifiers.		used for generating IPv6 interface identifiers.
	3.4. MTU of NFC Link Layer		3.4. MTU of NFC Link Layer
	As mentioned in Section 3.2, an IPv6 packet SHALL passed down to LLCP		As mentioned in Section 3.2, an IPv6 packet MUST be passed down to
	of NFC and transported to an Unnumbered Information Protocol Data		LLCP of NFC and transported to an Unnumbered Information Protocol
	Unit (UI PDU) and an Information Field in Protocol Data Unit (I PDU)		Data Unit (UI PDU) and an Information Field in Protocol Data Unit (I
	of LLCP of the NFC-enabled peer device.		PDU) of LLCP of the NFC-enabled peer device.
	The information field of an I PDU SHALL contain a single service data		The information field of an I PDU contains a single service data
	unit. The maximum number of octets in the information field is		unit. The maximum number of octets in the information field is
	determined by the Maximum Information Unit (MIU) for the data link		determined by the Maximum Information Unit (MIU) for the data link
	connection. The default value of the MIU for I PDUs SHALL be 128		connection. The default value of the MIU for I PDUs is 128 octets.
	octets. The local and remote LLCs each establish and maintain		The local and remote LLCs each establish and maintain distinct MIU
	distinct MIU values for each data link connection endpoint. Also, an		values for each data link connection endpoint. Also, an LLC MAY
	LLC MAY announce a larger MIU for a data link connection by		announce a larger MIU for a data link connection by transmitting an
	transmitting an MIUX extension parameter within the information		MIUX extension parameter within the information field. If no MIUX
	field. If no MIUX parameter is transmitted, the default MIU value of		parameter is transmitted, the default MIU value of 128 MUST be used.
	128 SHALL be used. Otherwise, the MTU size in NFC LLCP SHALL		Otherwise, the MTU size in NFC LLCP SHOULD be calculated from the MIU
	calculate the MIU value as follows:		value as follows:
	MIU = 128 + MIUX.		MIU = 128 + MIUX.
	When the MIUX parameter is encoded as a TLV, the TLV Type field SHALL		According to [LLCP-1.3], Figure 2 shows an example of the MIUX
	be 0x02 and the TLV Length field SHALL be 0x02. The MIUX parameter		parameter TLV. Each of TLV Type and TLV Length field is 1 byte, and
	SHALL be encoded into the least significant 11 bits of the TLV Value		TLV Value field is 2 bytes.
	field. The unused bits in the TLV Value field SHALL be set to zero
	by the sender and SHALL be ignored by the receiver. However, a		0 0 1 2 3
	maximum value of the TLV Value field can be 0x7FF, and a maximum size		0 8 6 2 1
	of the MTU in NFC LLCP is 2176 bytes.		+--------+--------+----------------+
			| Type | Length | Value |
			+--------+--------+----+-----------+
			|00000010|00000010|1011| MIUX |
			+--------+--------+----+-----------+
			| <-------> |
			0x000 ~ 0x7FF
			Figure 2: Example of MIUX Parameter TLV
			When the MIUX parameter is encoded as a TLV option, the TLV Type
			field MUST be 0x02 and the TLV Length field MUST be 0x02. The MIUX
			parameter MUST be encoded into the least significant 11 bits of the
			TLV Value field. The unused bits in the TLV Value field MUST be set
			to zero by the sender and ignored by the receiver. A maximum value
			of the TLV Value field can be 0x7FF, and a maximum size of the MTU in
			NFC LLCP is 2176 bytes including the 128 byte default of MIU.
	4. Specification of IPv6 over NFC		4. Specification of IPv6 over NFC
	NFC technology also has considerations and requirements owing to low		NFC technology also has considerations and requirements owing to low
	power consumption and allowed protocol overhead. 6LoWPAN standards		power consumption and allowed protocol overhead. 6LoWPAN standards
	[RFC4944], [RFC6775], and [RFC6282] provide useful functionality for		[RFC4944], [RFC6775], and [RFC6282] provide useful functionality for
	reducing overhead which can be applied to NFC. This functionality		reducing overhead which can be applied to NFC. This functionality
	consists of link-local IPv6 addresses and stateless IPv6 address		consists of link-local IPv6 addresses and stateless IPv6 address
	auto-configuration (see Section 4.3), Neighbor Discovery (see		auto-configuration (see Section 4.3), Neighbor Discovery (see
	Section 4.5) and header compression (see Section 4.7).		Section 4.5) and header compression (see Section 4.7).
	4.1. Protocol Stacks		4.1. Protocol Stacks
	Figure 2 illustrates IPv6 over NFC. Upper layer protocols can be		Figure 3 illustrates IPv6 over NFC. Upper layer protocols can be
	transport layer protocols (TCP and UDP), application layer protocols,		transport layer protocols (TCP and UDP), application layer protocols,
	and others capable running on top of IPv6.		and others capable running on top of IPv6.
	| | Transport &		| | Transport &
	| Upper Layer Protocols | Application Layer		| Upper Layer Protocols | Application Layer
	+----------------------------------------+ <------------------		+----------------------------------------+ <------------------
	| | |		| | |
	| IPv6 | |		| IPv6 | |
	| | Network		| | Network
	+----------------------------------------+ Layer		+----------------------------------------+ Layer
	skipping to change at page 7, line 41 ¶		skipping to change at page 8, line 25 ¶
	| Logical Link Control Protocol | NFC Link Layer		| Logical Link Control Protocol | NFC Link Layer
	| (LLCP) | |		| (LLCP) | |
	+----------------------------------------+ <------------------		+----------------------------------------+ <------------------
	| | |		| | |
	| Activities | NFC		| Activities | NFC
	| Digital Protocol | Physical Layer		| Digital Protocol | Physical Layer
	| RF Analog | |		| RF Analog | |
	| | |		| | |
	+----------------------------------------+ <------------------		+----------------------------------------+ <------------------
	Figure 2: Protocol Stacks for IPv6 over NFC		Figure 3: Protocol Stacks for IPv6 over NFC
	The adaptation layer for IPv6 over NFC SHALL support neighbor		The adaptation layer for IPv6 over NFC SHALL support neighbor
	discovery, stateless address auto-configuration, header compression,		discovery, stateless address auto-configuration, header compression,
	and fragmentation & reassembly.		and fragmentation & reassembly.
	4.2. Link Model		4.2. Link Model
	In the case of BT-LE, the Logical Link Control and Adaptation		In the case of BT-LE, the Logical Link Control and Adaptation
	Protocol (L2CAP) supports fragmentation and reassembly (FAR)		Protocol (L2CAP) supports fragmentation and reassembly (FAR)
	functionality; therefore, the adaptation layer for IPv6 over BT-LE		functionality; therefore, the adaptation layer for IPv6 over BT-LE
	does not have to conduct the FAR procedure. The NFC LLCP, in		does not have to conduct the FAR procedure. The NFC LLCP, in
	contrast, does not support the FAR functionality, so IPv6 over NFC		contrast, does not support the FAR functionality, so IPv6 over NFC
	needs to consider the FAR functionality, defined in [RFC4944].		needs to consider the FAR functionality, defined in [RFC4944].
	However, the MTU on an NFC link can be configured in a connection		However, the MTU on an NFC link can be configured in a connection
	procedure and extended enough to fit the MTU of IPv6 packet (see		procedure and extended enough to fit the MTU of IPv6 packet (see
	Section 4.8).		Section 4.8).
			This document does NOT RECOMMEND using FAR over NFC link due to
			simplicity of the protocol and implementation. In addition, the
			implementation for this specification SHOULD use MIUX extension to
			communicate the MTU of the link to the peer as defined in
			Section 3.4.
	The NFC link between two communicating devices is considered to be a		The NFC link between two communicating devices is considered to be a
	point-to-point link only. Unlike in BT-LE, an NFC link does not		point-to-point link only. Unlike in BT-LE, an NFC link does not
	support a star topology or mesh network topology but only direct		support a star topology or mesh network topology but only direct
	connections between two devices. Furthermore, the NFC link layer		connections between two devices. Furthermore, the NFC link layer
	does not support packet forwarding in link layer. Due to this		does not support packet forwarding in link layer. Due to this
	characteristics, 6LoWPAN functionalities, such as addressing and		characteristics, 6LoWPAN functionalities, such as addressing and
	auto-configuration, and header compression, need to be specialized		auto-configuration, and header compression, need to be specialized
	into IPv6 over NFC.		into IPv6 over NFC.
	4.3. Stateless Address Autoconfiguration		4.3. Stateless Address Autoconfiguration
	skipping to change at page 8, line 32 ¶		skipping to change at page 9, line 22 ¶
	autoconfiguration as per [RFC4862]. A 64-bit Interface identifier		autoconfiguration as per [RFC4862]. A 64-bit Interface identifier
	(IID) for an NFC interface is formed by utilizing the 6-bit NFC LLCP		(IID) for an NFC interface is formed by utilizing the 6-bit NFC LLCP
	address (see Section 3.3). In the viewpoint of address		address (see Section 3.3). In the viewpoint of address
	configuration, such an IID SHOULD guarantee a stable IPv6 address		configuration, such an IID SHOULD guarantee a stable IPv6 address
	because each data link connection is uniquely identified by the pair		because each data link connection is uniquely identified by the pair
	of DSAP and SSAP included in the header of each LLC PDU in NFC.		of DSAP and SSAP included in the header of each LLC PDU in NFC.
	Following the guidance of [RFC7136], interface identifiers of all		Following the guidance of [RFC7136], interface identifiers of all
	unicast addresses for NFC-enabled devices are 64 bits long and		unicast addresses for NFC-enabled devices are 64 bits long and
	constructed by using the generation algorithm of random (but stable)		constructed by using the generation algorithm of random (but stable)
	identifier (RID) [RFC7217] (see Figure 3).		identifier (RID) [RFC7217] (see Figure 4).
	0 1 3 4 6		0 1 3 4 6
	0 6 2 8 3		0 6 2 8 3
	+---------+---------+---------+---------+		+---------+---------+---------+---------+
	| Random (but stable) Identifier (RID) |		| Random (but stable) Identifier (RID) |
	+---------+---------+---------+---------+		+---------+---------+---------+---------+
	Figure 3: IID from NFC-enabled device		Figure 4: IID from NFC-enabled device
	The RID is an output which MAY be created by the algorithm, F() with		The RID is an output which MAY be created by the algorithm, F() with
	input parameters. One of the parameters is Net_IFace, and NFC Link		input parameters. One of the parameters is Net_IFace, and NFC Link
	Layer address (i.e., SSAP) MAY be a source of the NetIFace parameter.		Layer address (i.e., SSAP) MAY be a source of the NetIFace parameter.
	The 6-bit address of SSAP of NFC is easy and short to be targeted by		The 6-bit address of SSAP of NFC is easy and short to be targeted by
	attacks of third party (e.g., address scanning). The F() can provide		attacks of third party (e.g., address scanning). The F() can provide
	secured and stable IIDs for NFC-enabled devices.		secured and stable IIDs for NFC-enabled devices.
	In addition, the "Universal/Local" bit (i.e., the 'u' bit) of an NFC-		In addition, the "Universal/Local" bit (i.e., the 'u' bit) of an NFC-
	enabled device address MUST be set to 0 [RFC4291].		enabled device address MUST be set to 0 [RFC4291].
	4.4. IPv6 Link Local Address		4.4. IPv6 Link Local Address
	Only if the NFC-enabled device address is known to be a public		Only if the NFC-enabled device address is known to be a public
	address, the "Universal/Local" bit be set to 1. The IPv6 link-local		address, the "Universal/Local" bit be set to 1. The IPv6 link-local
	address for an NFC-enabled device is formed by appending the IID, to		address for an NFC-enabled device is formed by appending the IID, to
	the prefix FE80::/64, as depicted in Figure 4.		the prefix FE80::/64, as depicted in Figure 5.
	0 0 0 1		0 0 0 1
	0 1 6 2		0 1 6 2
	0 0 4 7		0 0 4 7
	+----------+------------------+----------------------------+		+----------+------------------+----------------------------+
	|1111111010| zeros | Interface Identifier |		|1111111010| zeros | Interface Identifier |
	+----------+------------------+----------------------------+		+----------+------------------+----------------------------+
	| |		| |
	| <---------------------- 128 bits ----------------------> |		| <---------------------- 128 bits ----------------------> |
	| |		| |
	Figure 4: IPv6 link-local address in NFC		Figure 5: IPv6 link-local address in NFC
	The tool for a 6LBR to obtain an IPv6 prefix for numbering the NFC		The tool for a 6LBR to obtain an IPv6 prefix for numbering the NFC
	network is can be accomplished via DHCPv6 Prefix Delegation		network is can be accomplished via DHCPv6 Prefix Delegation
	([RFC3633]).		([RFC3633]).
	4.5. Neighbor Discovery		4.5. Neighbor Discovery
	Neighbor Discovery Optimization for 6LoWPANs ([RFC6775]) describes		Neighbor Discovery Optimization for 6LoWPANs ([RFC6775]) describes
	the neighbor discovery approach in several 6LoWPAN topologies, such		the neighbor discovery approach in several 6LoWPAN topologies, such
	as mesh topology. NFC does not support a complicated mesh topology		as mesh topology. NFC does not support a complicated mesh topology
	skipping to change at page 9, line 50 ¶		skipping to change at page 10, line 43 ¶
	Option (ARO) and process the Neighbor Advertisement (NA)		Option (ARO) and process the Neighbor Advertisement (NA)
	accordingly. In addition, if DHCPv6 is used to assign an address,		accordingly. In addition, if DHCPv6 is used to assign an address,
	Duplicate Address Detection (DAD) MAY not be required.		Duplicate Address Detection (DAD) MAY not be required.
	o When two or more NFC 6LNs meet, there MAY be two cases. One is		o When two or more NFC 6LNs meet, there MAY be two cases. One is
	that they meet with multi-hop connections, and the other is that		that they meet with multi-hop connections, and the other is that
	they meet within a sigle hop range (e.g., isolated network). In a		they meet within a sigle hop range (e.g., isolated network). In a
	case of multi-hops, all of 6LNs, which have two or more		case of multi-hops, all of 6LNs, which have two or more
	connections with different neighbors, MAY be a router for		connections with different neighbors, MAY be a router for
	6LR/6LBR. In a case that they meet within a single hop and they		6LR/6LBR. In a case that they meet within a single hop and they
	have the same properties, any of them can be a router. Unless		have the same properties, any of them can be a router. When the
	they are the same (e.g., different MTU, level of remaining energy,		NFC nodes are not of uniform category (e.g., different MTU, level
	connectivity, etc.), a performance-outstanding device can become a		of remaining energy, connectivity, etc.), a performance-
	router. Also, they MAY deliver their own information (e.g., MTU		outstanding device can become a router. Also, they MUST deliver
	and energy level, etc.) to neighbors with NFC LLCP protocols		their MTU information to neighbors with NFC LLCP protocols during
	during connection initialization.		connection initialization. The router MAY also communicate other
			capabilities which is out of scope of this document.
	o For sending Router Solicitations and processing Router		o For sending Router Solicitations and processing Router
	Advertisements, the NFC 6LNs MUST follow Sections 5.3 and 5.4 of		Advertisements, the NFC 6LNs MUST follow Sections 5.3 and 5.4 of
	RFC 6775.		[RFC6775].
	4.6. Dispatch Header		4.6. Dispatch Header
	All IPv6-over-NFC encapsulated datagrams are prefixed by an		All IPv6-over-NFC encapsulated datagrams are prefixed by an
	encapsulation header stack consisting of a Dispatch value followed by		encapsulation header stack consisting of a Dispatch value followed by
	zero or more header fields. The only sequence currently defined for		zero or more header fields. The only sequence currently defined for
	IPv6-over-NFC is the LOWPAN_IPHC header followed by payload, as		IPv6-over-NFC is the LOWPAN_IPHC header followed by payload, as
	depicted in Figure 5.		depicted in Figure 6.
	+---------------+---------------+--------------+		+---------------+---------------+--------------+
	| IPHC Dispatch | IPHC Header | Payload |		| IPHC Dispatch | IPHC Header | Payload |
	+---------------+---------------+--------------+		+---------------+---------------+--------------+
	Figure 5: A IPv6-over-NFC Encapsulated 6LOWPAN_IPHC Compressed IPv6		Figure 6: A IPv6-over-NFC Encapsulated 6LOWPAN_IPHC Compressed IPv6
	Datagram		Datagram
	The dispatch value may be treated as an unstructured namespace. Only		The dispatch value may be treated as an unstructured namespace. Only
	a single pattern is used to represent current IPv6-over-NFC		a single pattern is used to represent current IPv6-over-NFC
	functionality.		functionality.
	+------------+--------------------+-----------+		+------------+--------------------+-----------+
	| Pattern | Header Type | Reference |		| Pattern | Header Type | Reference |
	+------------+--------------------+-----------+		+------------+--------------------+-----------+
	| 01 1xxxxx | 6LOWPAN_IPHC | [RFC6282] |		| 01 1xxxxx | 6LOWPAN_IPHC | [RFC6282] |
	+------------+--------------------+-----------+		+------------+--------------------+-----------+
	Figure 6: Dispatch Values		Figure 7: Dispatch Values
	Other IANA-assigned 6LoWPAN Dispatch values do not apply to this		Other IANA-assigned 6LoWPAN Dispatch values do not apply to this
	specification.		specification.
	4.7. Header Compression		4.7. Header Compression
	Header compression as defined in [RFC6282], which specifies the		Header compression as defined in [RFC6282], which specifies the
	compression format for IPv6 datagrams on top of IEEE 802.15.4, is		compression format for IPv6 datagrams on top of IEEE 802.15.4, is
	REQUIRED in this document as the basis for IPv6 header compression on		REQUIRED in this document as the basis for IPv6 header compression on
	top of NFC. All headers MUST be compressed according to RFC 6282		top of NFC. All headers MUST be compressed according to RFC 6282
	encoding formats.		encoding formats.
	Therefore, IPv6 header compression in [RFC6282] MUST be implemented.		Therefore, IPv6 header compression in [RFC6282] MUST be implemented.
	Further, implementations MAY also support Generic Header Compression		Further, implementations MAY also support Generic Header Compression
	(GHC) of [RFC7400].		(GHC) of [RFC7400].
	If a 16-bit address is required as a short address, it MUST be formed		If a 16-bit address is required as a short address, it MUST be formed
	by padding the 6-bit NFC link-layer (node) address to the left with		by padding the 6-bit NFC link-layer (node) address to the left with
	zeros as shown in Figure 7.		zeros as shown in Figure 8.
	0 1		0 1
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Padding(all zeros)| NFC Addr. |		| Padding(all zeros)| NFC Addr. |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 7: NFC short address format		Figure 8: NFC short address format
	4.8. Fragmentation and Reassembly		4.8. Fragmentation and Reassembly
	NFC provides fragmentation and reassembly (FAR) for payloads from 128		IPv6-over-NFC fragmentation and reassembly (FAR) for the payloads is
	bytes up to 2176 bytes as mentioned in Section 3.4. The MTU of a		NOT RECOMMENDED in this document as discussed in Section 3.4. The
	general IPv6 packet can fit into a single NFC link frame. Therefore,		NFC link connection for IPv6 over NFC MUST be configured with an
	the FAR functionality as defined in RFC 4944, which specifies the
	fragmentation methods for IPv6 datagrams on top of IEEE 802.15.4, MAY
	NOT be required as the basis for IPv6 datagram FAR on top of NFC.
	The NFC link connection for IPv6 over NFC MUST be configured with an
	equivalent MIU size to fit the MTU of IPv6 Packet. If NFC devices		equivalent MIU size to fit the MTU of IPv6 Packet. If NFC devices
	support extension of the MTU, the MIUX value is 0x480 in order to fit		support extension of the MTU, the MIUX value is 0x480 in order to fit
	the MTU (1280 bytes) of a IPv6 packet.		the MTU (1280 bytes) of a IPv6 packet.
	4.9. Unicast Address Mapping		4.9. Unicast and Multicast Address Mapping
	The address resolution procedure for mapping IPv6 non-multicast		The address resolution procedure for mapping IPv6 non-multicast
	addresses into NFC link-layer addresses follows the general		addresses into NFC link-layer addresses follows the general
	description in Section 7.2 of [RFC4861], unless otherwise specified.		description in Section 7.2 of [RFC4861], unless otherwise specified.
	The Source/Target link-layer Address option has the following form		The Source/Target link-layer Address option has the following form
	when the addresses are 6-bit NFC link-layer (node) addresses.		when the addresses are 6-bit NFC link-layer (node) addresses.
	0 1		0 1
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Type | Length=1 |		| Type | Length=1 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| |		| |
	+- Padding (all zeros) -+		+- Padding (all zeros) -+
	| |		| |
	+- +-+-+-+-+-+-+		+- +-+-+-+-+-+-+
	| | NFC Addr. |		| | NFC Addr. |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 8: Unicast address mapping		Figure 9: Unicast address mapping
	Option fields:		Option fields:
	Type:		Type:
	1: for Source Link-layer address.		1: for Source Link-layer address.
	2: for Target Link-layer address.		2: for Target Link-layer address.
	Length:		Length:
	This is the length of this option (including the type and		This is the length of this option (including the type and
	length fields) in units of 8 octets. The value of this field		length fields) in units of 8 octets. The value of this field
	is 1 for 6-bit NFC node addresses.		is 1 for 6-bit NFC node addresses.
	NFC address:		NFC address:
	The 6-bit address in canonical bit order. This is the unicast		The 6-bit address in canonical bit order. This is the unicast
	address the interface currently responds to.		address the interface currently responds to.
	4.10. Multicast Address Mapping		The NFC Link Layer does not support multicast. Therefore, packets
			are always transmitted by unicast between two NFC-enabled devices.
	All IPv6 multicast packets MUST be sent to NFC Destination Address,		Even in the case where a 6LBR is attached to multiple 6LNs, the 6LBR
	0x3F (broadcast) and be filtered at the IPv6 layer. When represented		cannot do a multicast to all the connected 6LNs. If the 6LBR needs
	as a 16-bit address in a compressed header, it MUST be formed by		to send a multicast packet to all its 6LNs, it has to replicate the
	padding on the left with a zero. In addition, the NFC Destination		packet and unicast it on each link.
	Address, 0x3F, MUST NOT be used as a unicast NFC address of SSAP or
	DSAP.
	0 1
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Padding(all zeros)|1 1 1 1 1 1|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 9: Multicast address mapping
	5. Internet Connectivity Scenarios		5. Internet Connectivity Scenarios
	As two typical scenarios, the NFC network can be isolated and		As two typical scenarios, the NFC network can be isolated and
	connected to the Internet.		connected to the Internet.
	5.1. NFC-enabled Device Connected to the Internet		5.1. NFC-enabled Device Connected to the Internet
	One of the key applications of using IPv6 over NFC is securely		One of the key applications of using IPv6 over NFC is securely
	transmitting IPv6 packets because the RF distance between 6LN and		transmitting IPv6 packets because the RF distance between 6LN and
	skipping to change at page 14, line 45 ¶		skipping to change at page 15, line 10 ¶
	IPv6-over-NFC uses an IPv6 interface identifier formed from a "Short		IPv6-over-NFC uses an IPv6 interface identifier formed from a "Short
	Address" and a set of well-known constant bits (such as padding with		Address" and a set of well-known constant bits (such as padding with
	'0's) for the modified EUI-64 format. However, the short address of		'0's) for the modified EUI-64 format. However, the short address of
	NFC link layer (LLC) is not generated as a physically permanent value		NFC link layer (LLC) is not generated as a physically permanent value
	but logically generated for each connection. Thus, every single		but logically generated for each connection. Thus, every single
	touch connection can use a different short address of NFC link with		touch connection can use a different short address of NFC link with
	an extremely short-lived link. This can mitigate address scanning as		an extremely short-lived link. This can mitigate address scanning as
	well as location tracking and device-specific vulnerability		well as location tracking and device-specific vulnerability
	exploitation.		exploitation.
			Thus, this document does not RECOMMEND sending NFC packets over the
			Internet or any unsecured network.
			If there is a compelling reason to send/receive the IPv6-over-NFC
			packets over the unsecured network, the deployment SHOULD make sure
			that the packets are sent over secured channels. The particular
			Security mechanisms are out of scope of this document.
	8. Acknowledgements		8. Acknowledgements
	We are grateful to the members of the IETF 6lo working group.		We are grateful to the members of the IETF 6lo working group.
	Michael Richardson, Suresh Krishnan, Pascal Thubert, Carsten Bormann,		Michael Richardson, Suresh Krishnan, Pascal Thubert, Carsten Bormann,
	Alexandru Petrescu, James Woodyatt, Dave Thaler, Samita Chakrabarti,		Alexandru Petrescu, James Woodyatt, Dave Thaler, Samita Chakrabarti,
	and Gabriel Montenegro have provided valuable feedback for this		and Gabriel Montenegro have provided valuable feedback for this
	draft.		draft.
	9. References		9. References
	skipping to change at page 16, line 20 ¶		skipping to change at page 16, line 46 ¶
	Interface Identifiers with IPv6 Stateless Address		Interface Identifiers with IPv6 Stateless Address
	Autoconfiguration (SLAAC)", RFC 7217,		Autoconfiguration (SLAAC)", RFC 7217,
	DOI 10.17487/RFC7217, April 2014,		DOI 10.17487/RFC7217, April 2014,
	<https://www.rfc-editor.org/info/rfc7217>.		<https://www.rfc-editor.org/info/rfc7217>.
	[RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for		[RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for
	IPv6 over Low-Power Wireless Personal Area Networks		IPv6 over Low-Power Wireless Personal Area Networks
	(6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November		(6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November
	2014, <https://www.rfc-editor.org/info/rfc7400>.		2014, <https://www.rfc-editor.org/info/rfc7400>.
			[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
			2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
			May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	9.2. Informative References		9.2. Informative References
	[ECMA-340]		[ECMA-340]
	"Near Field Communication - Interface and Protocol (NFCIP-		"Near Field Communication - Interface and Protocol (NFCIP-
	1) 3rd Ed.", ECMA-340 , June 2013.		1) 3rd Ed.", ECMA-340 , June 2013.
	Authors' Addresses		Authors' Addresses
	Younghwan Choi (editor)		Younghwan Choi (editor)
	Electronics and Telecommunications Research Institute		Electronics and Telecommunications Research Institute
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