wdiff draft-ietf-6lo-nfc-15.txt draft-ietf-6lo-nfc-16.txt

6Lo Working Group Y. Choi, Ed.
Internet-Draft Y-G. Hong
Intended status: Standards Track ETRI
Expires: January 9, 2020 10, 2021 J-S. Youn
Dongeui Univ
D-K. Kim
KNU
J-H. Choi
Samsung Electronics Co.,
July 8, 2019 9, 2020

Transmission of IPv6 Packets over Near Field Communication
draft-ietf-6lo-nfc-15
draft-ietf-6lo-nfc-16

Abstract

Near field communication Field Communication (NFC) is a set of standards for smartphones
and portable devices to establish radio communication with each other
by touching them together or bringing them into proximity, usually no
more than 10 cm apart. NFC standards cover communications protocols
and data exchange formats, and are based on existing radio-frequency
identification (RFID) standards including ISO/IEC 14443 and FeliCa.
The standards include ISO/IEC 18092 and those defined by the NFC
Forum. The NFC technology has been widely implemented and available
in mobile phones, laptop computers, and many other devices. This
document describes how IPv6 is transmitted over NFC using 6LoWPAN
techniques.

Status of This Memo

This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on January 9, 2020. 10, 2021.

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Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 3
3. Overview of Near Field Communication Technology . . . . . . . 3
3.1. Peer-to-peer Mode of NFC . . . . . . . . . . . . . . . . 4 3
3.2. Protocol Stacks of NFC . . . . . . . . . . . . . . . . . 4
3.3. NFC-enabled Device Addressing . . . . . . . . . . . . . . 5
3.4. MTU of NFC Link Layer . . . . . . . . . . . . . . . . . . 6 5
4. Specification of IPv6 over NFC . . . . . . . . . . . . . . . 7 6
4.1. Protocol Stacks . . . . . . . . . . . . . . . . . . . . . 7 6
4.2. Link Model . . . . . . . . . . . . . . . . . . . . . . . 7
4.3. Stateless Address Autoconfiguration . . . . . . . . . . . 8
4.4. 7
4.3. IPv6 Link Local Link-Local Address . . . . . . . . . . . . . . . . . 9
4.5. 8
4.4. Neighbor Discovery . . . . . . . . . . . . . . . . . . . 9
4.6. 8
4.5. Dispatch Header . . . . . . . . . . . . . . . . . . . . . 10
4.7. 9
4.6. Header Compression . . . . . . . . . . . . . . . . . . . 10
4.8. 9
4.7. Fragmentation and Reassembly Considerations . . . . . . . 11
4.9. 10
4.8. Unicast and Multicast Address Mapping . . . . . . . . . . 11 10
5. Internet Connectivity Scenarios . . . . . . . . . . . . . . . 12 11
5.1. NFC-enabled Device Connected to the Internet . . . . . . 13 11
5.2. Isolated NFC-enabled Device Network . . . . . . . . . . . 13 12
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 12
7. Security Considerations . . . . . . . . . . . . . . . . . . . 14 12
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 13
9. Normative References . . . . . . . . . . . . . . . . . . . . 14 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 14

1. Introduction

NFC is a set of short-range wireless technologies, typically
requiring a distance between sender and receiver of 10 cm or less.
NFC operates at 13.56 MHz on
ISO/IEC 18000-3 air interface MHz, and at rates ranging from 106 kbit/s to
424 kbit/s kbit/s, as per the ISO/IEC 18000-3 air interface [ECMA-340]. NFC
builds upon RFID systems by allowing two-way communication between
endpoints. NFC always involves an initiator and a target; the
initiator actively generates an RF field that can power a passive
target. This enables NFC targets to take very simple form
factors factors,
such as tags, stickers, key fobs, or cards that do not
require cards, while avoiding the need
for batteries. NFC peer-to-peer communication is possible, provided
that both devices are powered. NFC builds upon RFID systems by
allowing two-way communication between endpoints. At the time As of
this writing, it has been used in devices such as mobile phones,
running Android operating system, named with a feature called
"Android Beam". It is expected for the other mobile phones, running
other operating systems (e.g., iOS, etc.) to be equipped with NFC
technology in the near future.

Considering exponential growth in the number of heterogeneous air
interface technologies, writing, NFC has been widely used like Bluetooth Low
Energy (BT-LE), Wi-Fi, and so on. Each of the heterogeneous air
interface technologies has its own characteristics, which cannot be
covered is supported
by the other technologies, so various kinds of air interface
technologies would co-exist together. main smartphone operating systems.

NFC can provide secured is often regarded as a secure communications with technology, due to
its very short transmission range.

When the number of devices and things having different air interface
technologies communicate with each other, IPv6

In order to benefit from Internet connectivity, it is an ideal internet
protocol owing desirable for
NFC-enabled devices to support IPv6, considering its large address space. Also, NFC would be one of
the endpoints using IPv6. Therefore, this
space, along with tools for unattended operation, among other
advantages. This document describes specifies how IPv6 is transmitted supported over NFC
by using 6LoWPAN techniques.

[RFC4944] specifies the transmission of IPv6 over IEEE 802.15.4. The
NFC link also has similar characteristics to Low-power Wireless Personal Area Network (6LoWPAN)
techniques [RFC4944], [RFC6282], [RFC6775]. 6LoWPAN is suitable,
considering that of it was designed to support IPv6 over IEEE 802.15.4.
Many 802.15.4
networks, and some of the mechanisms defined in [RFC4944] can be applied to the
transmission characteristics of IPv6 on NFC links. This document specifies the
details latter are similar
to those of IPv6 transmission over NFC links. NFC.

2. Conventions and Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"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

This section presents an overview of NFC, focusing on the
characteristics of NFC that are most relevant for supporting IPv6.

NFC enables simple and two-way simple, two-way, interaction between two devices,
allowing consumers users to perform contactless transactions, access digital
content, and connect electronic devices with a single touch. NFC complements many popular consumer level wireless technologies, by
utilizing the
utilizes key elements in existing standards for contactless card
technology (ISO/IEC
Technology, such as ISO/IEC 14443 A&B and JIS-X 6319-4). NFC can be
compatible with existing contactless card infrastructure and it
enables a consumer to utilize one device across different systems.

Extending the capability of contactless card technology, 6319-4. NFC also
enables allows
devices to share information at a distance that is less than up to 10 cm with a maximum communication speed
physical layer bit rate of 424 kbps. Users can
share business cards, make transactions, access information from a
smart poster or provide credentials for access control systems with a
simple touch.

3.1. Peer-to-peer Mode of NFC

NFC-enabled devices are unique in that they can support

NFC defines three modes of operation: card emulation, peer-to-peer,
and reader/writer. Only
peer-to-peer in the three modes peer-to-peer mode enables two NFC-enabled NFC-
enabled devices to communicate with each other to exchange
information and share files, so that users of NFC-enabled devices can
quickly share contact information and other files with a touch. The
other two modes does not support two-way communications between two
devices. Therefore, the peer mode is used for ipv6-over-nfc. In addition, NFC-enabled devices can
securely send IPv6 packets in wireless range when an NFC-enabled
gateway is linked to the Internet.

3.2. Protocol Stacks of NFC

IP can use the services provided by

NFC defines a protocol stack for the Logical Link Control peer-to-peer mode (Figure 1).
The peer-to-peer mode is made in Activities Digital Protocol
(LLCP) in the NFC stack to provide reliable, two-way transmission of
information between the peer devices. Figure 1 depicts the
Physical Lay. The NFC P2P
protocol stack with IPv6 bindings to LLCP.

For data communication in IPv6 over NFC, an IPv6 packet MUST be
passed down to LLCP Logical Link consists of NFC and transported to an Information (I) Binding for IPv6-LLCP
and
an Unnumbered Information (UI) Field in Logical Link Control Protocol Data Unit (PDU) of
LLCP of the NFC-enabled peer device. LLCP does not support
fragmentation and reassembly. For Layer (LLCP). IPv6 addressing or address
configuration, LLCP MUST provide related information, such as link
layer addresses, to and its upper layer. The LLCP to IPv6 protocol
binding MUST transfer
underlying adaptation Layer (i.e., IPv6-over-NFC adaptation layer)
are placed directly on the SSAP and DSAP value to top of the IPv6-LLCP Binding. An IPv6 over NFC
protocol. SSAP stands for Source Service Access Point, which
datagram is a
6-bit value meaning a kind of transmitted by the Logical Link Control (LLC) address,
while DSAP means an LLC address Protocol (LLCP)
with reliable, two-way transmission of information between the destination NFC-enabled
device.

Figure 1: Protocol Stacks Stack of NFC

The LLCP consists of Logical Link Control (LLC) and MAC Mapping. The
MAC Mapping integrates an existing RF protocol into the LLCP
architecture. The LLC contains three components, such as Link
Management, Connection-oriented Transmission, and Connection-less
Transmission. The Link Management component is responsible for
serializing all connection-oriented and connection-less LLC PDU
(Protocol Data Unit) exchanges and for aggregation and disaggregation
of small PDUs. The Connection-oriented Transmission component is
responsible for maintaining all connection-oriented data exchanges
including connection set-up and termination. The Connectionless
Transmission component is responsible for handling unacknowledged
data exchanges.

In order to send an IPv6 packet over NFC, the packet MUST be passed
down to the LLCP layer of NFC and carried by an Information (I) or an
Unnumbered Information (UI) Field in an LLCP Protocol Data Unit
(PDU). LLCP does not support fragmentation and reassembly. For IPv6
addressing or address configuration, LLCP MUST provide related
information, such as link layer addresses, to its upper layer. The
LLCP to IPv6 protocol binding MUST transfer the SSAP and DSAP value
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
(LLC) address, while DSAP means an LLC address of the destination
NFC-enabled device. Thus, SSAP is a source address, and DSAP is a
destination address.

3.3. NFC-enabled Device Addressing

According to NFC Logical Link Control Protocol v1.3 [LLCP-1.3], NFC-
enabled devices have two types of 6-bit addresses (i.e., SSAP and
DSAP) to identify service access points. The several Several service access
points can be installed on a NFC device. However, the SSAP and DSAP
can be used as identifiers for NFC link connections with the IPv6
over NFC adaptation layer. Therefore, the SSAP can be used to
generate an IPv6 interface identifier. Address values between 00h
and 0Fh of SSAP and DSAP are reserved for identifying the well-known
service access points, which are defined in the NFC Forum Assigned
Numbers Register. Address values between 10h and 1Fh are assigned by
the local LLC to services registered by local service environment.
In addition, address values between 20h and 3Fh are assigned by the
local LLC as a result of an upper layer service request. Therefore,
the address values between 20h and 3Fh can be used for generating
IPv6 interface identifiers.

3.4. MTU of NFC Link Layer

As mentioned in Section 3.2, when an IPv6 packet is transmitted, the
packet MUST be passed down to LLCP of NFC and transported to an
Unnumbered Information Protocol Data Unit (UI PDU) and an Information
Field in Protocol Data Unit (I PDU) of LLCP of the NFC-enabled peer
device.

The information field of an I PDU contains a single service data
unit. The maximum number of octets in the information field is
determined by the Maximum Information Unit (MIU) for the data link
connection. The default value of the MIU for I PDUs is 128 octets.
The local and remote LLCs each establish and maintain distinct MIU
values for each data link connection endpoint. Also, an LLC is may
announce a larger MIU for a data link connection by transmitting an
MIUX extension
optional Maximum Information Unit Extension (MIUX) parameter within
the information field. If no MIUX parameter is transmitted, the MIU
value is 128 bytes. Otherwise, the MTU size in NFC LLCP MUST be
calculated from the MIU value as follows:

MTU = MIU = 128 + MIUX.

According to [LLCP-1.3], Figure 2 shows an example of the MIUX
parameter TLV. Each of TLV The Type and TLV Length field is fields of the MIUX parameter TLV
have each a size of 1 byte, and byte. The size of the TLV Value field is 2
bytes.

0 0 1 2 3
0 8 6 2 1
+----------+----------+------+-----------+
| Type | Length | Value |
+----------+----------+------+-----------+
| 00000010 | 00000010 | 1011 | 0x0~0x7FF |
+----------+----------+------+-----------+

Figure 2: Example of MIUX Parameter TLV

When the MIUX parameter is encoded as a TLV option, used, 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 The maximum possible value of
the TLV Value field can be is 0x7FF, and a the maximum size of the MTU in
NFC LLCP MTU is
2176 bytes including bytes. If fragmentation functionality is not used at the 128 byte default of MIU. This
adaptation layer between IPv6 and NFC, the MIUX value MUST be 0x480
to cover MTU of IPV6 if FAR is not used in support the IPv6
over NFC. MTU requirement (of 1280 bytes).

4. Specification of IPv6 over NFC

NFC technology also has considerations and requirements owing to low
power consumption and allowed protocol overhead. 6LoWPAN standards
[RFC4944], [RFC6775], and [RFC6282] provide useful functionality for
reducing overhead which can be applied to NFC. This functionality
consists of link-local IPv6 addresses and stateless IPv6 address
auto-configuration (see Section 4.3), 4.2), Neighbor Discovery (see
Section 4.5) 4.4) and header compression (see Section 4.7). 4.6).

4.1. Protocol Stacks

Figure 3 illustrates IPv6 over NFC. Upper layer protocols can be
transport layer protocols (TCP (e.g., TCP and UDP), application layer
protocols, and others capable of running on top of IPv6.

| |
| Upper Layer Protocols |
+----------------------------------------+
| IPv6 |
+----------------------------------------+
| Adaptation Layer for IPv6 over NFC |
+----------------------------------------+
| NFC Link Layer |
+----------------------------------------+
| NFC Physical Layer |
+----------------------------------------+

Figure 3: Protocol Stacks Stack for IPv6 over NFC

The adaptation layer for IPv6 over NFC support supports neighbor discovery,
stateless address auto-configuration, header compression, and
fragmentation & reassembly.

4.2. Link Model

In the case of BT-LE, the Logical Link Control and Adaptation
Protocol (L2CAP) supports fragmentation and reassembly (FAR)
functionality; therefore, the adaptation layer for IPv6 over BT-LE
does not have to conduct the FAR procedure. The NFC LLCP, in
contrast, does not support the FAR functionality, so IPv6 over NFC
needs to consider the FAR functionality, defined in [RFC4944].
However, the MTU reassembly, based on an NFC link can be configured in a connection
procedure and extended enough to fit the MTU of IPv6 packet (see
Section 4.8).

This document does NOT RECOMMEND using FAR over NFC link. In
addition, the implementation for this specification MUST 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
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
connections between two devices. Furthermore, the NFC link layer
does not support packet forwarding in link layer. Due to this
characteristics, 6LoWPAN functionalities, such as addressing and
auto-configuration, and header compression, need to be specialized
into IPv6 over NFC.

4.3. 6LoWPAN.

4.2. Stateless Address Autoconfiguration

An NFC-enabled device (i.e., 6LN) performs stateless address autoconfiguration as
per [RFC4862]. A 64-bit Interface identifier (IID) for an NFC
interface is formed by utilizing the 6-bit NFC SSAP (see
Section 3.3). In the viewpoint of address configuration, such an IID
should guarantee a stable IPv6 address during the course of a single
connection, 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.

Following the guidance of [RFC7136], interface identifiers of all
unicast addresses for NFC-enabled devices are 64 bits long and
constructed by using the generation algorithm of random (but stable)
identifier (RID) [RFC7217] (see Figure 4).

0 1 3 4 6
0 6 2 8 3
+---------+---------+---------+---------+
| Random (but stable) Identifier (RID) |
+---------+---------+---------+---------+

Figure 4: IID from NFC-enabled device

The RID is an output which is created by the algorithm, F() with
input parameters. One of the parameters is Net_IFace, Net_Iface, and NFC Link
Layer address (i.e., SSAP) is a source of the NetIFace Net_Iface parameter.
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
secured and stable IIDs for NFC-enabled devices. In addition, an
optional parameter, Network_ID is used to increase the randomness of
the generated IID.

4.4.

4.3. IPv6 Link Local Link-Local Address

The IPv6 link-local address for an NFC-enabled device is formed by
appending the IID, to the prefix FE80::/64, as depicted in Figure 5.

0 0 0 1
0 1 6 2
0 0 4 7
+----------+------------------+----------------------------+
|1111111010| zeros | Interface Identifier |
+----------+------------------+----------------------------+
| |
| <---------------------- 128 bits ----------------------> |
| |

Figure 5: IPv6 link-local address in NFC

The tool for a

A 6LBR to may obtain an IPv6 prefix for numbering the NFC network can be accomplished via
DHCPv6 Prefix Delegation ([RFC3633]). The "Interface Identifier" is used the can
be a secured and stable IIDs for
NFC-enabled devices.

4.5. IIDs.

4.4. Neighbor Discovery

Neighbor Discovery Optimization for 6LoWPANs ([RFC6775]) describes
the neighbor discovery approach in several 6LoWPAN topologies, such
as mesh topology. NFC does not support a complicated supports mesh topology topologies but only most of all
applications would use a simple multi-hop network topology or
directly connected peer-to-peer network. Therefore, the following aspects of RFC 6775
are applicable to NFC: network because NFC RF range is very
short.

o When an NFC-enabled device (6LN) 6LN is directly connected to a NFC-
enabled 6LBR, an NFC-enabled
6LBR, the NFC 6LN MUST register its address with the
6LBR[RFC4944] 6LBR by
sending a Neighbor Solicitation (NS) message with the Address
Registration Option (ARO) (ARO), and process the Neighbor Advertisement
(NA) accordingly. In addition, when the 6LN and 6LBR are directly
connected, DHCPv6 is used for address assignment. Therefore,
Duplicate Address Detection (DAD) is not necessary between them.

o When two or more NFC 6LNs[RFC4944](or 6LRs) devices are connected, there are two cases.
One is that three or more NFC devices are linked with multi-hop
connections, and the other is that they meet within a single hop
range (e.g., isolated network). In a case of multi-
hops, all of 6LNs, multi-hop topology,
devices which have two or more connections with
different neighbors, is neighbor devices,
play a router for 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.

o For sending Router Solicitations and processing Router
Advertisements, the NFC 6LNs MUST follow Sections 5.3 and 5.4 of
[RFC6775].

o When a NFC device becomes is a 6LR or a 6LBR, the NFC device MUST follow
Section 6 and 7 of [RFC6775].

4.6.

4.5. Dispatch Header

All IPv6-over-NFC encapsulated datagrams are prefixed by an
encapsulation header stack consisting of a Dispatch value followed by
zero or more header fields. value. The only
sequence currently defined for IPv6-over-NFC is the LOWPAN_IPHC 6LOWPAN_IPHC
header followed by payload, as depicted in Figure 6.

+---------------+---------------+--------------+
| IPHC Dispatch | IPHC Header | Payload |
+---------------+---------------+--------------+

Figure 6: A IPv6-over-NFC Encapsulated 6LOWPAN_IPHC Compressed IPv6
Datagram

The dispatch value is treated as an unstructured namespace. Only a
single pattern is used to represent current IPv6-over-NFC
functionality.

+------------+--------------------+-----------+
| Pattern | Header Type | Reference |
+------------+--------------------+-----------+
| 01 1xxxxx | 6LOWPAN_IPHC | [RFC6282] |
+------------+--------------------+-----------+

Figure 7: Dispatch Values

Other IANA-assigned 6LoWPAN Dispatch values do not apply to this
specification.

4.7.

4.6. Header Compression

Header compression as defined in [RFC6282], which specifies the
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
top of NFC. All headers MUST be compressed according to RFC 6282
encoding formats.

Therefore, IPv6 header compression in [RFC6282] MUST be implemented.
Further, implementations MUST also support Generic Header Compression
(GHC) of [RFC7400].

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
zeros as shown in Figure 8.

0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Padding(all zeros)| NFC Addr. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 8: NFC short address format

4.8.

4.7. Fragmentation and Reassembly Considerations

IPv6-over-NFC MUST SHOULD NOT use fragmentation and reassembly (FAR) for
the payloads as discussed in Section 3.4. The NFC link connection
for IPv6 over NFC MUST be configured with an equivalent MIU size to
fit the MTU of IPv6 Packet. The MIUX value is 0x480 in order to fit
the MTU (1280 bytes) of a IPv6 packet if NFC devices support
extension of the MTU. However, if the NFC device does not support extension,
IPv6-over-NFC uses FAR with the default MTU (128 bytes), as defined
in [RFC4944].

4.9.

4.8. Unicast and Multicast Address Mapping

The address resolution procedure for mapping IPv6 non-multicast
addresses into NFC link-layer addresses follows the general
description in Section 4.6.1 and 7.2 of [RFC4861], unless otherwise
specified.

The Source/Target link-layer Address option has the following form
when the addresses are 6-bit NFC link-layer (node) addresses.

0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length=1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- Padding (all zeros) -+
| |
+- +-+-+-+-+-+-+
| | NFC Addr. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 9: Unicast address mapping

Option fields:

Type:

1: for Source Link-layer address.

2: for Target Link-layer address.

Length:

This is the length of this option (including the type and
length fields) in units of 8 octets. The value of this field
is 1 for 6-bit NFC node addresses.

NFC address:

The 6-bit address in canonical bit order. This is the unicast
address the interface currently responds to.

The NFC Link Layer does not support multicast. Therefore, packets
are always transmitted by unicast between two NFC-enabled devices.
Even in the case where a 6LBR is attached to multiple 6LNs, the 6LBR
cannot do a multicast to all the connected 6LNs. If the 6LBR needs
to send a multicast packet to all its 6LNs, it has to replicate the
packet and unicast it on each link.

5. Internet Connectivity Scenarios

NFC networks can either be isolated and or connected to the Internet.

5.1. NFC-enabled Device Connected to the Internet

One of the key applications of using IPv6 over
The NFC is securely
transmitting IPv6 packets because the RF distance link between 6LN and
6LBR two communicating devices is typically within 10 cm. If any third party wants considered to hack
into the RF be a
point-to-point link only. An NFC link does not support a star
topology or mesh network topology but only direct connections between them, it must come to nearly touch them.
Applications can choose which kinds of air interfaces (e.g., BT-LE,
Wi-Fi, NFC, etc.)
two devices. The NFC link layer does not support packet forwarding
in link layer.

5.1. NFC-enabled Device Connected to send data depending on the characteristics of
the data. Internet

Figure 10 illustrates an example of an NFC-enabled device network
connected to the Internet. The distance between 6LN and 6LBR is
typically 10 cm or less. If there is any laptop computers close to a
user, it will become a 6LBR. Additionally, when the user mounts an
NFC-enabled air interface adapter (e.g., portable NFC dongle) on the
close laptop PC, the user's NFC-enabled device (6LN) can communicate
with the laptop PC (6LBR) within 10 cm distance.

Figure 10: NFC-enabled device network connected to the Internet

Two or more 6LNs are connected with a 6LBR, but each connection uses
a different subnet. The 6LBR is acting as a router and forwarding
packets between 6LNs and the Internet. Also, the 6LBR MUST ensure
address collisions do not occur and forwards packets sent by one 6LN
to another.

5.2. Isolated NFC-enabled Device Network

In some scenarios, the NFC-enabled device network may transiently be
a simple isolated network as shown in the Figure 11.

Figure 11: Isolated NFC-enabled device network

In mobile phone markets, applications are designed and made by user
developers. They may image interesting applications, where three or
more mobile phones touch or attach each other to work achieve a
common objective. In an isolated NFC-enabled device network, when
two or more 6LRs are connected with each other, and then they are
acting like routers, the 6LR MUST ensure address collisions do not
occur.

6. IANA Considerations

There are no IANA considerations related to this document.

7. Security Considerations

This document does not RECOMMEND sending NFC packets over

There are the
Internet or any unsecured network. intrinsic security properties of NFC due to its short
link range. When interface identifiers (IIDs) are generated, devices
and users are required to consider mitigating various threats, such
as correlation of activities over time, location tracking, device-
specific vulnerability exploitation, and address scanning.

IPv6-over-NFC uses an IPv6 interface identifier formed from a "Short
Address" and a set of well-known constant bits for the modified
EUI-64 format. However, NFC applications use short-lived
connections, and the every connection is made with a different address
of NFC link with an extremely short-lived link.

This document does not RECOMMEND sending NFC packets over the
Internet or any unsecured network. Especially, there can be a threat
model in the scenario of Section 5.1. when the NFC-enabled device
links to a NFC-enabled gateway is used for connectivity with the Internet,
the gateway can be attacked. Even though IPv6 over NFC guarantees
security between each connection,
where the two NFC devices, there can be another threat
during packet forwarding. latter is of extremely short duration.

8. Acknowledgements

We are grateful to the members of the IETF 6lo working group.

Michael Richardson, Suresh Krishnan, Pascal Thubert, Carsten Bormann,
Alexandru Petrescu, James Woodyatt, Dave Thaler, Samita Chakrabarti,
and
Gabriel Montenegro and Carles Gomez Montenegro have provided valuable
feedback for this
draft. document.

9. Normative References

[ECMA-340]
"Near Field Communication - Interface and Protocol (NFCIP-
1) 3rd Ed.", ECMA-340 , June 2013.

[LLCP-1.3]
"NFC Logical Link Control Protocol version 1.3", NFC Forum
Technical Specification , March 2016.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.

[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633,
DOI 10.17487/RFC3633, December 2003,
<https://www.rfc-editor.org/info/rfc3633>.

[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>.

[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>.

[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
"Transmission of IPv6 Packets over IEEE 802.15.4
Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007,
<https://www.rfc-editor.org/info/rfc4944>.

[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011,
<https://www.rfc-editor.org/info/rfc6282>.

[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012,
<https://www.rfc-editor.org/info/rfc6775>.

[RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6
Interface Identifiers", RFC 7136, DOI 10.17487/RFC7136,
February 2014, <https://www.rfc-editor.org/info/rfc7136>.

[RFC7217] Gont, F., "A Method for Generating Semantically Opaque
Interface Identifiers with IPv6 Stateless Address
Autoconfiguration (SLAAC)", RFC 7217,
DOI 10.17487/RFC7217, April 2014,
<https://www.rfc-editor.org/info/rfc7217>.

[RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for
IPv6 over Low-Power Wireless Personal Area Networks
(6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November
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>.

Authors' Addresses

Younghwan Choi (editor)
Electronics and Telecommunications Research Institute
218 Gajeongno, Yuseung-gu
Daejeon 34129
Korea

Phone: +82 42 860 1429
Email: yhc@etri.re.kr
Yong-Geun Hong
Electronics and Telecommunications Research Institute
161 Gajeong-Dong Yuseung-gu
Daejeon 305-700
Korea

Phone: +82 42 860 6557
Email: yghong@etri.re.kr

Joo-Sang Youn
DONG-EUI University
176 Eomgwangno Busan_jin_gu
Busan 614-714
Korea

Phone: +82 51 890 1993
Email: joosang.youn@gmail.com

Dongkyun Kim
Kyungpook National University
80 Daehak-ro, Buk-gu
Daegu 702-701
Korea

Phone: +82 53 950 7571
Email: dongkyun@knu.ac.kr

JinHyouk Choi
Samsung Electronics Co.,
129 Samsung-ro, Youngdong-gu
Suwon 447-712
Korea

Phone: +82 2 2254 0114
Email: jinchoe@samsung.com