6Lo Working Group                                              Y-G. Hong
Internet-Draft                                                 Y-H. Choi
Intended status: Standards Track                                    ETRI
Expires: April 19, 2016                                 October 17, 2015


     Use cases for IPv6 over Networks of Resource-constrained Nodes
                      draft-hong-6lo-use-cases-00

Abstract

   This document describes the characteristics of link layer
   technologies that are used at constrained node networks and typical
   use cases of IPv6 over networks of resource-constrained nodes.  In
   addition to IEEE 802.15.4, various link layer technologies such as
   BLE, Z-wave, DECT-ULE, MS/TP, NFC, and IEEE 802.15.4e are widely used
   at constrained node networks for typical services.  Based on these
   link layer technologies, IPv6 over networks of resource-constrained
   nodes has various and practical use cases.  To efficiently implement
   typical services, the applicability and consideration of several
   design spaces are described.

Status of This Memo

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   publication of this document.  Please review these documents



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   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.  6lo Link layer technologies . . . . . . . . . . . . . . . . .   4
     3.1.  ITU-T G.9959  . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Bluetooth Low Energy  . . . . . . . . . . . . . . . . . .   4
     3.3.  DECT-ULE  . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.4.  Master-Slave/Token-Passing  . . . . . . . . . . . . . . .   5
     3.5.  NFC . . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.6.  IEEE 802.15.4e TSCH . . . . . . . . . . . . . . . . . . .   6
   4.  Design Space  . . . . . . . . . . . . . . . . . . . . . . . .   6
   5.  6lo Use Cases . . . . . . . . . . . . . . . . . . . . . . . .   7
     5.1.  Use case of NFC: Alternative Secure Transfer  . . . . . .   7
     5.2.  Use case of ITU-T G.9959  . . . . . . . . . . . . . . . .   9
     5.3.  Use case of Bluetooth Low Energy  . . . . . . . . . . . .   9
     5.4.  Use case of DECT-ULE  . . . . . . . . . . . . . . . . . .   9
     5.5.  Use case of Master-Slave/Token-Passing  . . . . . . . . .  10
     5.6.  Use case of IEEE 802.15.4e TSCH . . . . . . . . . . . . .  10
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   Running IPv6 on constrained node networks has different features due
   to the characteristics of constrained node networks such as small
   packet size, short link-layer address, low bandwidth, network
   topology, low power, low cast, and large number of devices [RFC4919].
   For example, because some IEEE 802.15.4 link layers have an MTU of
   127 octets and IPv6 requires 1280 bytes, an appropriate fragmentation
   and reassembly adaptation layer must be provided at the layer of
   below IPv6.  Also, due to the limited size of IEEE 802.15.4 frame and
   the length shortage of data delivery, it makes the need for header
   compression.  IETF 6lowpan (IPv6 over low power and WPAN) working
   group published [RFC4944], an adaptation layer for sending IPv6
   packets over low power WPAN, [RFC6282], compression format for IPv6




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   datagrams over IEEE 802.15.4-based networks, and [RFC6775], Neighbor
   Discovery Optimization for 6lowpan.

   As IoT (Internet of Things) services becomes more popular, various
   link layer technologies such as BLE, Z-wave, DECT-ULE, MS/TP, NFC,
   and IEEE 802.15.4e are actively used.  And the need of transmission
   of IPv6 packets over these link layer technologies is required.  A
   number of IPv6-over-foo documents have been developed in the IETF 6lo
   (IPv6 over Networks of Resource-constrained Nodes) and 6tisch (IPv6
   over the TSCH mode of IEEE 802.15.4e) working group.

   In the 6lowpan working group, the [RFC6568], "Design and Application
   Spaces for 6LoWPANs" was published and it describes potential
   application scenarios and use cases for low-power wireless personal
   area networks.  In this document, various design spaces such as
   deployment, network size, power source, connectivity, multi-hop
   communication, traffic pattern, security level, mobility, and QoS
   were analyzed.  And it described a fundamental set of 6lowpan
   application scenarios and use cases; Industrial monitoring-Hospital
   storage rooms, Structural monitoring-Bridge safety monitoring,
   Connected home-Home Automation, Healthcare-Healthcare at home by
   tele-assistance, Vehicle telematics-telematics, and Agricultural
   monitoring-Automated vineyard.

   Even though the [RFC6568] describes some potential application
   scenarios and use cases and it lists the design space in the context
   of 6lowpan, it needs a different use cases and design space in the
   context of the 6lo working group to provide practical information of
   6lo technologies.  To do this, the use case of 6lo is required to
   consider the followings;

   o  6lo use cases SHOULD be uniquely different to the 6lowpan use
      cases.

   o  6lo use cases SHOULD cover various IoT related wire/wireless link
      layer technology including the IEEE 802.15.4.

   o  6lo use cases MAY describe characteristics of each link layer
      technologies and typical use case of each link layer technology
      and then 6lo use cases's applicability.

2.  Conventions and Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].





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3.  6lo Link layer technologies

3.1.  ITU-T G.9959

   The ITU-T G.9959 recommendation G.  [G.9959] targets low-power
   Personal Area Networks (PANs).  G.9959 defines how a unique 32-bit
   HomeID network identifier is assigned by a network controller and how
   an 8-bit NodeID host identifier is allocated to each node.  NodeIDs
   are unique within the network identified by the HomeID.  The G.9959
   HomeID represents an IPv6 subnet that is identified by one or more
   IPv6 prefixes [RFC7428].

3.2.  Bluetooth Low Energy

   Bluetooth LE was introduced in Bluetooth 4.0, enhanced in Bluetooth
   4.1, and developed even further in successive versions.  Bluetooth
   SIG has also published Internet Protocol Support Profile (IPSP),
   which includes Internet Protocol Support Service (IPSS).  The IPSP
   enables discovery of IP-enabled devices and establishment of link-
   layer connection for transporting IPv6 packets.  IPv6 over Bluetooth
   LE is dependent on both Bluetooth 4.1 and IPSP 1.0 or newer.

   Devices such as mobile phones, notebooks, tablets and other handheld
   computing devices which will include Bluetooth 4.1 chipsets will also
   have the low-energy functionality of Bluetooth.  Bluetooth LE will
   also be included in many different types of accessories that
   collaborate with mobile devices such as phones, tablets and notebook
   computers.  An example of a use case for a Bluetooth LE accessory is
   a heart rate monitor that sends data via the mobile phone to a server
   on the Internet [I-D.ietf-6lo-btle].

3.3.  DECT-ULE

   DECT ULE is a low power air interface technology that is designed to
   support both circuit switched for service, such as voice
   communication, and for packet mode data services at modest data rate.

   The DECT ULE protocol stack consists of the PHY layer operating at
   frequencies in the 1880 - 1920 MHz frequency band depending on the
   region and uses a symbol rate of 1.152 Mbps.  Radio bearers are
   allocated by use of FDMA/TDMA/TDD technics.

   In its generic network topology, DECT is defined as a cellular
   network technology.  However, the most common configuration is a star
   network with a single FP defining the network with a number of PP
   attached.  The MAC layer supports both traditional DECT as this is
   used for services like discovery, pairing, security features etc.
   All these features have been reused from DECT.



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   The DECT ULE device can switch to the ULE mode of operation,
   utilizing the new ULE MAC layer features.  The DECT ULE Data Link
   Control (DLC) provides multiplexing as well as segmentation and re-
   assembly for larger packets from layers above.  The DECT ULE layer
   also implements per-message authentication and encryption.  The DLC
   layer ensures packet integrity and preserves packet order, but
   delivery is based on best effort.

   The current DECT ULE MAC layer standard supports low bandwidth data
   broadcast.  However the usage of this broadcast service has not yet
   been standardized for higher layers [I-D.ietf-6lo-dect-ule].

3.4.  Master-Slave/Token-Passing

   Master-Slave/Token-Passing (MS/TP) is a contention-free access method
   for the RS-485 physical layer, which is used extensively in building
   automation networks.  This specification defines the frame format for
   transmission of IPv6 [RFC2460] packets and the method of forming
   link-local and statelessly autoconfigured IPv6 addresses on MS/TP
   networks.  The general approach is to adapt elements of the 6LoWPAN
   [RFC4944] specification to constrained wired networks.

   An MS/TP device is typically based on a low-cost microcontroller with
   limited processing power and memory.  Together with low data rates
   and a small address space, these constraints are similar to those
   faced in 6LoWPAN networks and suggest some elements of that solution
   might be leveraged.  MS/TP differs significantly from 6LoWPAN in at
   least three respects: a) MS/TP devices typically have a continuous
   source of power, b) all MS/TP devices on a segment can communicate
   directly so there are no hidden node or mesh routing issues, and c)
   recent changes to MS/TP provide support for large payloads,
   eliminating the need for link-layer fragmentation and reassembly.

   MS/TP is designed to enable multidrop networks over shielded twisted
   pair wiring.  It can support a data rate of 115,200 baud on segments
   up to 1000 meters in length, or segments up to 1200 meters in length
   at lower baud rates.  An MS/TP link requires only a UART, an RS-485
   transceiver with a driver that can be disabled, and a 5ms resolution
   timer.  These features make MS/TP a cost-effective field bus for the
   most numerous and least expensive devices in a building automation
   network [I-D.ietf-6lo-6lobac].

3.5.  NFC

   NFC technology enables simple and safe two-way interactions between
   electronic devices, allowing consumers to perform contactless
   transactions, access digital content, and connect electronic devices
   with a single touch.  NFC complements many popular consumer level



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   wireless technologies, by utilizing the key elements in existing
   standards for contactless card technology (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, NFC also
   enables devices to share information at a distance that is less than
   10 cm with a maximum communication speed 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.

   NFC's bidirectional communication ability is ideal for establishing
   connections with other technologies by the simplicity of touch.  In
   addition to the easy connection and quick transactions, simple data
   sharing is also available [I-D.ietf-6lo-nfc].

3.6.  IEEE 802.15.4e TSCH

   [TBD]

4.  Design Space

   The [RFC6568] lists the dimensions used to describe the design space
   of wireless sensor networks in the context of the 6LoWPAN working
   group.  The design space is already limited by the unique
   characteristics of a LoWPAN (e.g., low power, short range, low bit
   rate).  In the RFC 6558, the following design space is described;
   Deployment, Network size, Power source, Connectivity, Multi-hop
   communication, Traffic pattern, Mobility, Quality of Service (QoS).

   The design space of 6lo is a little different to those of the RFC
   6558 due to the different characteristics of 6lo link layer
   technologies.  The following design space can be considered.

   o  Network access/Bootstrapping: 6lo nodes can be connected randomly,
      or in an organized manner.  The bootstrapping has different
      characteristics of each link layer technologies.

   o  Topology: Topology of 6lo networks may inherently follow the
      characteristics of each link layer technologies.  A star topology
      can be configured or point-to-point or mesh topology can be
      configured.

   o  L2-Mesh or L3-Mesh: L2-mesh and L3-mesh may inherently follow the
      characteristics of each link layer technologies.  Some link layer
      technologies may support L2-mesh and some may not support.



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   o  Multi-link subnet, single subnet: The selection of multi-link
      subnet and single subnet depends on connectivity and the number of
      6lo nodes.

   o  Data rate: Originally, the link layer technologies of 6lo has low
      rate of data transmission.  But, by adjusting the MTU, it can
      deliver higher data rate.

   o  Buffering requirements: Some 6lo use case may require more data
      rate than the link layer technology support.  In this case, a
      buffering mechanism to manage the date is required.

   o  Security Requirements: Some 6lo use case can transfer some
      important and personal data between 6lo nodes.  In this case,
      high-level security support is required.

   o  Mobility across 6lo networks and subnets: The movement of 6lo
      nodes is dependent on the 6lo use case.  If the 6lo nodes can move
      or moved around, it requires the mobility management mechanism.

   o  Time synchronization requirements: The requirement of time
      synchronization is dependent on the 6lo use case.  For some 6lo
      use case related to health service, the measured data must be
      recorded with exact time and must be transferred with time
      synchronization.

   o  Reliability and QoS: Some 6lo use case requires high reliability,
      for example real-time service or health-related services.

   o  Data models: 6lo use case may various data models.  Some 6lo use
      case may require short data length and randomly.  Some 6lo use
      case may require continuous data and periodic data transmission.

   o  Security Bootstrapping: Without the external operations, 6lo nodes
      must have the security bootstrapping mechanism.

5.  6lo Use Cases

5.1.  Use case of NFC: Alternative Secure Transfer

   According to applications, various secured data can be handled and
   transferred.  Depending on security level of the data, methods for
   transfer can be alternatively selected.  The personal data having
   serious issues should be transferred securely, but data transfer by
   using Wi-Fi and Bluetooth connections cannot always be secure because
   of their a little long radio frequency range.  Hackers can overhear
   the personal data transfer behind hidden areas.  Therefore, methods
   need to be alternatively selected to transfer secured data.  Voice



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   and video data, which are not respectively secure and requires long
   transmission range, can be transferred by 3G/4G technologies, such as
   WCDMA, GSM, and LTE.  Big size data, which are not secure and
   requires high speed and broad bandwidth, can be transferred by Wi-Fi
   and wired network technologies.  However, the person data, which are
   serious issues so requires secure transfer in wireless area, can be
   securely transferred by NFC technology.  It has very short frequency
   range ? nearly single touch communication.

   Example: Secure Transfer by Using NFC in Healthcare Services with
   Tele-Assistance

   A senior citizen who lives alone wears one to several wearable 6lo
   devices to measure heartbeat, pulse rate, etc.  The 6lo devices are
   densely installed at home for movement detection.  An LoWPAN Border
   Router (LBR) at home will send the sensed information to a connected
   healthcare center.  Portable base stations with LCDs may be used to
   check the data at home, as well.  Data is gathered in both periodic
   and event-driven fashion.  In this application, event-driven data can
   be very time-critical.  In addition, privacy also becomes a serious
   issue in this case, as the sensed data is very personal.

   While the senior citizen is provided audio and video healthcare
   services by a tele-assistance based on LTE connections, the senior
   citizen can alternatively use NFC connections to transfer the
   personal sensed data to the tele-assistance.  At this moment, hidden
   hackers can overhear the data based on the LTE connection, but they
   cannot gather the personal data over the NFC connection.


       +-------------+                              +-------------+
       |voice & video|....... LTE connection ......>|voice & video|
       |     data    |<...... LTE connection .......|    data     |
       +-------------+                              +-------------+
       | sensed data |....... NFC connection ......>|             |
       |             |<...... NFC connection .......|   personal  |
       |             |                              | result data |
       +-------------+                              +-------------+
          (patient)                                (tele-assistance)


       Figure 1: Alternative Secure Transfer in Healthcare Services

   Dominant parameters in secure transfer by using NFC in healthcare
   services:

   o  Network access/Bootstrapping: Pre-planned.  MP2P/P2MP (data
      collection), P2P (local diagnostic).



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   o  Topology: Small, NFC-enabled device connected to the Internet.

   o  L2-mesh or L3-mesh: NFC does not support L2-mesh, L3-mesh can be
      configured.

   o  Multi-link subnet, single subnet: a Single-hop for gateway;
      patient's body network is mesh topology.

   o  Data rate: Small data rate.

   o  Buffering requirements: Low requirement.

   o  Security requirements: Data privacy and security must be provided.
      Encryption is required.

   o  Mobility: Moderate (patient's mobility).

   o  Time Synchronization: Highly required.

   o  Reliability and QoS: High level of reliability support (life-or-
      death implication), role-based.

   o  Data models: Short data length and periodic (randomly).

   o  Security Bootstrapping: Highly required.

   o  Other Issues: Plug-and-play configuration is required for mainly
      non-technical end-users.  Real-time data acquisition and analysis
      are important.  Efficient data management is needed for various
      devices that have different duty cycles, and for role-based data
      control.  Reliability and robustness of the network are also
      essential.

5.2.  Use case of ITU-T G.9959

   [TBD]

5.3.  Use case of Bluetooth Low Energy

   [TBD]

5.4.  Use case of DECT-ULE

   [TBD]







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5.5.  Use case of Master-Slave/Token-Passing

   [TBD]

5.6.  Use case of IEEE 802.15.4e TSCH

   [TBD]

6.  IANA Considerations

   There are no IANA considerations related to this document.

7.  Security Considerations

   [TBD]

8.  Acknowledgements

   [TBD]

9.  References

9.1.  Normative References

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

   [RFC4919]  Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6
              over Low-Power Wireless Personal Area Networks (6LoWPANs):
              Overview, Assumptions, Problem Statement, and Goals",
              RFC 4919, DOI 10.17487/RFC4919, August 2007,
              <http://www.rfc-editor.org/info/rfc4919>.

   [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,
              <http://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,
              <http://www.rfc-editor.org/info/rfc6282>.







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   [RFC6568]  Kim, E., Kaspar, D., and JP. Vasseur, "Design and
              Application Spaces for IPv6 over Low-Power Wireless
              Personal Area Networks (6LoWPANs)", RFC 6568,
              DOI 10.17487/RFC6568, April 2012,
              <http://www.rfc-editor.org/info/rfc6568>.

   [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,
              <http://www.rfc-editor.org/info/rfc6775>.

   [RFC7428]  Brandt, A. and J. Buron, "Transmission of IPv6 Packets
              over ITU-T G.9959 Networks", RFC 7428,
              DOI 10.17487/RFC7428, February 2015,
              <http://www.rfc-editor.org/info/rfc7428>.

9.2.  Informative References

   [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
              December 1998, <http://www.rfc-editor.org/info/rfc2460>.

   [I-D.ietf-6lo-btle]
              Nieminen, J., Savolainen, T., Isomaki, M., Patil, B.,
              Shelby, Z., and C. Gomez, "IPv6 over BLUETOOTH(R) Low
              Energy", draft-ietf-6lo-btle-17 (work in progress), August
              2015.

   [I-D.ietf-6lo-dect-ule]
              Mariager, P., Petersen, J., Shelby, Z., Logt, M., and D.
              Barthel, "Transmission of IPv6 Packets over DECT Ultra Low
              Energy", draft-ietf-6lo-dect-ule-03 (work in progress),
              September 2015.

   [I-D.ietf-6lo-6lobac]
              Lynn, K., Martocci, J., Neilson, C., and S. Donaldson,
              "Transmission of IPv6 over MS/TP Networks", draft-ietf-
              6lo-6lobac-02 (work in progress), July 2015.

   [I-D.ietf-6lo-nfc]
              Youn, J. and Y. Hong, "Transmission of IPv6 Packets over
              Near Field Communication", draft-ietf-6lo-nfc-01 (work in
              progress), July 2015.







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   [G.9959]   "International Telecommunication Union, "Short range
              narrow-band digital radiocommunication transceivers - PHY
              and MAC layer specifications", ITU-T Recommendation",
              January 2015.

Authors' Addresses

   Yong-Geun Hong
   ETRI
   161 Gajeong-Dong Yuseung-Gu
   Daejeon  305-700
   Korea

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


   Younghwan Choi
   ETRI
   218 Gajeongno, Yuseong
   Daejeon  305-700
   Korea

   Phone: +82 42 860 1429
   Email: yhc@etri.re.kr


























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