Transmission of IPv6 Packets over Near Field Communication
draft-ietf-6lo-nfc-17

Document Type Active Internet-Draft (6lo WG)
Last updated 2020-08-23
Replaces draft-hong-6lo-ipv6-over-nfc
Stream IETF
Intended RFC status Proposed Standard
Formats plain text xml pdf htmlized (tools) htmlized bibtex
Reviews
Stream WG state Submitted to IESG for Publication
Document shepherd Carles Gomez
Shepherd write-up Show (last changed 2019-03-05)
IESG IESG state IESG Evaluation::AD Followup
Consensus Boilerplate Yes
Telechat date
Needs a YES. Has 2 DISCUSSes. Needs 7 more YES or NO OBJECTION positions to pass.
Responsible AD Erik Kline
Send notices to Samita Chakrabarti <samitac.ietf@gmail.com>, Carles Gomez <carlesgo@entel.upc.edu>
IANA IANA review state Version Changed - Review Needed
6Lo Working Group                                           Y. Choi, Ed.
Internet-Draft                                                 Y-G. Hong
Intended status: Standards Track                                    ETRI
Expires: February 24, 2021                                     J-S. Youn
                                                            Dongeui Univ
                                                                D-K. Kim
                                                                     KNU
                                                               J-H. Choi
                                                Samsung Electronics Co.,
                                                         August 23, 2020

       Transmission of IPv6 Packets over Near Field Communication
                         draft-ietf-6lo-nfc-17

Abstract

   Near 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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 24, 2021.

Choi, et al.            Expires February 24, 2021               [Page 1]
Internet-Draft                IPv6 over NFC                  August 2020

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

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  . . . . . . . . . . . . . . . .   3
     3.2.  Protocol Stack of NFC . . . . . . . . . . . . . . . . . .   4
     3.3.  NFC-enabled Device Addressing . . . . . . . . . . . . . .   5
     3.4.  MTU of NFC Link Layer . . . . . . . . . . . . . . . . . .   5
   4.  Specification of IPv6 over NFC  . . . . . . . . . . . . . . .   6
     4.1.  Protocol Stack  . . . . . . . . . . . . . . . . . . . . .   6
     4.2.  Stateless Address Autoconfiguration . . . . . . . . . . .   7
     4.3.  IPv6 Link-Local Address . . . . . . . . . . . . . . . . .   8
     4.4.  Neighbor Discovery  . . . . . . . . . . . . . . . . . . .   8
     4.5.  Dispatch Header . . . . . . . . . . . . . . . . . . . . .   9
     4.6.  Header Compression  . . . . . . . . . . . . . . . . . . .   9
     4.7.  Fragmentation and Reassembly Considerations . . . . . . .  10
     4.8.  Unicast and Multicast Address Mapping . . . . . . . . . .  10
   5.  Internet Connectivity Scenarios . . . . . . . . . . . . . . .  11
     5.1.  NFC-enabled Device Network Connected to the Internet  . .  11
     5.2.  Isolated NFC-enabled Device Network . . . . . . . . . . .  12
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  13
   9.  Normative References  . . . . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  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, and at rates ranging from 106 kbit/s to
   424 kbit/s, as per the ISO/IEC 18000-3 air interface [ECMA-340].  NFC

Choi, et al.            Expires February 24, 2021               [Page 2]
Internet-Draft                IPv6 over NFC                  August 2020

   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,
   such as tags, stickers, key fobs, or cards, while avoiding the need
   for batteries.  NFC peer-to-peer communication is possible, provided
   that both devices are powered.  As of the writing, NFC is supported
   by the main smartphone operating systems.

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

   In order to benefit from Internet connectivity, it is desirable for
   NFC-enabled devices to support IPv6, considering its large address
   space, along with tools for unattended operation, among other
   advantages.  This document specifies how IPv6 is supported over NFC
   by using IPv6 over Low-power Wireless Personal Area Network (6LoWPAN)
   techniques [RFC4944], [RFC6282], [RFC6775]. 6LoWPAN is suitable,
   considering that it was designed to support IPv6 over IEEE 802.15.4
   networks, and some of the characteristics of the latter are similar
   to those of 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, two-way, interaction between two devices,
   allowing users to perform contactless transactions, access digital
   content, and connect electronic devices with a single touch.  NFC
   utilizes key elements in existing standards for contactless card
   Technology, such as ISO/IEC 14443 A&B and JIS-X 6319-4.  NFC allows
   devices to share information at a distance up to 10 cm with a maximum
   physical layer bit rate of 424 kbps.

3.1.  Peer-to-peer Mode of NFC

   NFC defines three modes of operation: card emulation, peer-to-peer,
   and reader/writer.  Only the peer-to-peer mode allows two NFC-enabled
   devices to communicate with each other to exchange information

Choi, et al.            Expires February 24, 2021               [Page 3]
Internet-Draft                IPv6 over NFC                  August 2020

   bidirectionally.  The other two modes do not support two-way
   communications between two devices.  Therefore, the peer-to-peer mode
   is used for IPv6 over NFC.

3.2.  Protocol Stack of NFC

   NFC defines a protocol stack for the peer-to-peer mode (Figure 1).
   The peer-to-peer mode is offered by the Activities Digital Protocol
   at the NFC Physical Layer.  The NFC Logical Link Layer comprises the
   Logical Link Control Protocol (LLCP), and when IPv6 is used over NFC,
   it also includes an IPv6-LLCP Binding.  IPv6 and its underlying
   adaptation Layer (i.e., IPv6-over-NFC adaptation layer) are placed
   directly on the top of the IPv6-LLCP Binding.  An IPv6 datagram is
   transmitted by the Logical Link Control Protocol (LLCP) with
   reliable, two-way transmission of information between the peer
   devices.

       +----------------------------------------+ - - - - - - - - -
       |              IPv6 - LLCP               |         .
       |                Binding                 |         .
       +----------------------------------------+        NFC
       |                                        |    Logical Link
       |      Logical Link Control Protocol     |       Layer
       |                 (LLCP)                 |         .
       |                                        |         .
       +----------------------------------------+ - - - - - - - - -
       |                                        |         .
       |               Activities               |         .
       |            Digital Protocol            |         .
       |                                        |    NFC Physical
       +----------------------------------------+       Layer
       |                                        |         .
       |               RF Analog                |         .
       |                                        |         .
       +----------------------------------------+ - - - - - - - - -

                      Figure 1: Protocol 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 Connectionless
   Transmission.  The Link Management component is responsible for
   serializing all connection-oriented and connectionless 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

Choi, et al.            Expires February 24, 2021               [Page 4]
Internet-Draft                IPv6 over NFC                  August 2020

   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 Field in
   an LLCP Protocol Data Unit (I PDU).  The LLCP does not support
   fragmentation and reassembly.  For IPv6 addressing or address
   configuration, the LLCP MUST provide related information, such as
   link layer addresses, to its upper layer.  The LLCP to IPv6 protocol
   binding MUST transfer the Source Service Access Point (SSAP) and
   Destination Service Access Point (DSAP) value to the IPv6 over NFC
   protocol.  SSAP is a Logical Link Control (LLC) address of the source
   NFC-enabled device with a size of 6 bits, 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 LLCP 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.  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 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 may
   announce a larger MIU for a data link connection by transmitting an
   optional Maximum Information Unit Extension (MIUX) parameter within

Choi, et al.            Expires February 24, 2021               [Page 5]
Internet-Draft                IPv6 over NFC                  August 2020

   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.  The Type and Length fields of the MIUX parameter TLV
   have each a size of 1 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 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.  The maximum possible value of
   the TLV Value field is 0x7FF, and the maximum size of the LLCP MTU is
   2175 bytes.  The MIUX value MUST be 0x480 to support the IPv6 MTU
   requirement (of 1280 bytes).

4.  Specification of IPv6 over NFC

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

4.1.  Protocol Stack

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

Choi, et al.            Expires February 24, 2021               [Page 6]
Internet-Draft                IPv6 over NFC                  August 2020

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

                Figure 3: Protocol Stack for IPv6 over NFC

   The adaptation layer for IPv6 over NFC supports neighbor discovery,
   stateless address auto-configuration, header compression, and
   fragmentation & reassembly, based on 6LoWPAN.

4.2.  Stateless Address Autoconfiguration

   An NFC-enabled device 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 F() algorithm with input
   parameters.  One of the parameters is Net_Iface, and NFC Link Layer
   address (i.e., SSAP) is a source of the Net_Iface parameter.  The
   6-bit address of SSAP of NFC is short and easy to be targeted by
   attacks of third party (e.g., address scanning).  The F() algorithm
   can provide secured and stable IIDs for NFC-enabled devices.  In

Choi, et al.            Expires February 24, 2021               [Page 7]
Internet-Draft                IPv6 over NFC                  August 2020

   addition, an optional parameter, Network_ID is used to increase the
   randomness of the generated IID.

4.3.  IPv6 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

   A 6LBR may obtain an IPv6 prefix for numbering the NFC network via
   DHCPv6 Prefix Delegation ([RFC3633]).  The "Interface Identifier" can
   be a secured and stable IID.

4.4.  Neighbor Discovery

   Neighbor Discovery Optimization for 6LoWPANs ([RFC6775]) describes
   the neighbor discovery approach in several 6LoWPAN topologies, such
   as mesh topology.  NFC supports mesh topologies but most of all
   applications would use a simple multi-hop network topology or
   directly connected peer-to-peer network because NFC RF range is very
   short.

   o  When an NFC-enabled 6LN is directly connected to an NFC-enabled
      6LBR, the NFC 6LN MUST register its address with the 6LBR by
      sending a Neighbor Solicitation (NS) message with the Extended
      Address Registration Option (EARO) [RFC8505], 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 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.  Two NFC devices might still talk to each other (point-to-
      point topology), but one of them may be connected to the Internet.
      In a case of multi-hop topology, devices which have two or more

Choi, et al.            Expires February 24, 2021               [Page 8]
Internet-Draft                IPv6 over NFC                  August 2020

      connections with neighbor devices, may act as routers.  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 is a 6LR or a 6LBR, the NFC device MUST follow
      Section 6 and 7 of [RFC6775].

4.5.  Dispatch Header

   All IPv6-over-NFC encapsulated datagrams are prefixed by an
   encapsulation header stack consisting of a Dispatch value.  The only
   sequence currently defined for IPv6-over-NFC is the LOWPAN_IPHC
   compressed IPv6 header (see Section 4.6) 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.

4.6.  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.

Choi, et al.            Expires February 24, 2021               [Page 9]
Internet-Draft                IPv6 over NFC                  August 2020

   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

4.7.  Fragmentation and Reassembly Considerations

   IIPv6-over-NFC MUST NOT use fragmentation and reassembly (FAR) at the
   adaptation layer 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 support the IPv6 MTU requirement (of 1280
   bytes).  To this end, the MIUX value is 0x480.

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

Choi, et al.            Expires February 24, 2021              [Page 10]
Internet-Draft                IPv6 over NFC                  August 2020

   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 or connected to the Internet.
   The NFC link between two communicating devices is considered to 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
   two devices.  The NFC link layer does not support packet forwarding
   at link layer.

5.1.  NFC-enabled Device Network Connected to the 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.  For example, a laptop computer that is
   connected to the Internet (e.g. via Wi-Fi, Ethernet, etc.) may also
   support NFC and act as a 6LBR.  Another NFC-enabled device may run as
   a 6LN and communicate with the 6LBR, as long as both are within each
   other's range.

Choi, et al.            Expires February 24, 2021              [Page 11]
Internet-Draft                IPv6 over NFC                  August 2020

                NFC link
       6LN ------------------- 6LBR -------( Internet )--------- CN
        .                        .                                .
        . <- - - - Subnet - - -> . < - - - IPv6 connection - - -> .
        .                        .         to the Internet        .

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

   Two or more 6LNs may be 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 permanently be
   a simple isolated network as shown in the Figure 11.

                               6LN                        6LN - - - - -
                                |                          |      .
                    NFC link - >|              NFC link - >|      .
                                |                          |      .
    6LN ---------------------- 6LR ---------------------- 6LR   Subnet
     .         NFC link                    NFC link        |      .
     .                                                     |      .
     .                                         NFC link - >|      .
     .                                                    6LN - - - - -
     .                                                     .
     . < - - - - - - - - - -  Subnet - - - - - - - - - - > .

              Figure 11: Isolated NFC-enabled device network

6.  IANA Considerations

   There are no IANA considerations related to this document.

7.  Security Considerations

   NFC is often considered to offer intrinsic security properties 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.

Choi, et al.            Expires February 24, 2021              [Page 12]
Internet-Draft                IPv6 over NFC                  August 2020

   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 a different address is used for each connection,
   where the 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,
   Gabriel Montenegro and Carles Gomez Montenegro have provided valuable
   feedback for this 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>.

Choi, et al.            Expires February 24, 2021              [Page 13]
Internet-Draft                IPv6 over NFC                  August 2020

   [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>.

   [RFC8505]  Thubert, P., Ed., Nordmark, E., Chakrabarti, S., and C.
              Perkins, "Registration Extensions for IPv6 over Low-Power
              Wireless Personal Area Network (6LoWPAN) Neighbor
              Discovery", RFC 8505, DOI 10.17487/RFC8505, November 2018,
              <https://www.rfc-editor.org/info/rfc8505>.

Authors' Addresses

Choi, et al.            Expires February 24, 2021              [Page 14]
Internet-Draft                IPv6 over NFC                  August 2020

   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

Choi, et al.            Expires February 24, 2021              [Page 15]