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
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at 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
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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
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[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
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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
| | | | | |
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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
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| 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
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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
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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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