IPv6 Maintenance WG                                            A. Brandt
Internet-Draft                                                  J. Buron
Intended status: Standards Track                           Sigma Designs
Expires: December 20, 2013                                 June 18, 2013

        Transmission of IPv6 packets over ITU-T G.9959 Networks


   This document describes the frame format for transmission of IPv6
   packets and a method of forming IPv6 link-local addresses and
   statelessly autoconfigured IPv6 addresses on ITU-T G.9959 networks.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in [RFC2119].

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 http://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 December 20, 2013.

Copyright Notice

   Copyright (c) 2013 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
   (http://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

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   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.  Author's notes  . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Reader's guidance . . . . . . . . . . . . . . . . . . . .   2
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Terms used  . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  G.9959 parameters to use for IPv6 transport . . . . . . . . .   4
     3.1.  Addressing mode . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  IPv6 Multicast support  . . . . . . . . . . . . . . . . .   4
     3.3.  G.9959 MAC PDU size and IPv6 MTU  . . . . . . . . . . . .   5
     3.4.  Transmission status indications . . . . . . . . . . . . .   5
     3.5.  Transmission security . . . . . . . . . . . . . . . . . .   5
   4.  LoWPAN Adaptation Layer and Frame Format  . . . . . . . . . .   6
     4.1.  Dispatch Header . . . . . . . . . . . . . . . . . . . . .   6
   5.  LoWPAN addressing . . . . . . . . . . . . . . . . . . . . . .   7
     5.1.  Stateless Address Autoconfiguration of routable IPv6
           addresses . . . . . . . . . . . . . . . . . . . . . . . .   8
     5.2.  IPv6 Link Local Address . . . . . . . . . . . . . . . . .   8
     5.3.  Unicast Address Mapping . . . . . . . . . . . . . . . . .   8
     5.4.  On the use of Neighbor Discovery technologies . . . . . .   9
       5.4.1.  Prefix and CID management (Route-over)  . . . . . . .  10
       5.4.2.  Prefix and CID management (Mesh-under)  . . . . . . .  10
   6.  Header Compression  . . . . . . . . . . . . . . . . . . . . .  10
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  12
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  12
     10.2.  Informative References . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Author's notes

   This chapter MUST be deleted before going for document last call.

1.1.  Reader's guidance

   This document borrows heavily from RFC4944, "Transmission of IPv6
   Packets over IEEE 802.15.4 Networks".  The process of creating this
   document was mainly a simplification; removing the following topics:

   o  EUI-64 link-layer addresses

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   o  Fragmentation layer

   o  Mesh routing

   The 16-bit short addresses of 802.15.4 have been changed to 8-bit
   G.9959 NodeIDs.

2.  Introduction

   The ITU-T G.9959 recommendation [G.9959] targets low-power Personal
   Area Networks (PANs).  This document defines the frame format for
   transmission of IPv6 [RFC2460] packets as well as the formation of
   IPv6 link-local addresses and statelessly autoconfigured IPv6
   addresses on G.9959 networks.

   The general approach is to adapt elements of [RFC4944] to G.9959
   networks.  G.9959 provides a Segmentation and Reassembly (SAR) layer
   for transmission of datagrams larger than the G.9959 MAC PDU.

   [RFC6775] updates [RFC4944] by specifying 6LoWPAN optimizations for
   IPv6 Neighbor Discovery (ND) (originally defined by [RFC4861]).  This
   document limits the use of [RFC6775] to prefix and Context ID
   assignment.  It is described how to construct an IID from a G.9959
   link-layer address.  Refer to Section 5.  If using that method,
   Duplicate Address Detection (DAD) is not needed.  Address
   registration is only needed in certain cases.

   In addition to IPv6 application communication, the frame format
   defined in this document may be used by IPv6 routing protocols such
   as RPL [RFC6550] or P2P-RPL [P2P-RPL] to implement IPv6 routing over
   G.9959 networks.

   G.9959 networks may implement mesh routing between nodes below the IP
   layer.  Mesh routing is out of scope of this document.

2.1.  Terms used

   ABR: Authoritative Border Router ([RFC6775])

   AES: Advanced Encryption Scheme

   EUI-64: Extended Unique Identifier

   HomeID: G.9959 Link-Layer Network Identifier

   IID: Interface IDentifier

   MAC: Media Access Control

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   MTU: Maximum Transmission Unit

   NodeID: G.9959 Link-Layer Node Identifier (Short Address)

   PAN: Personal Area Network

   PDU: Protocol Data Unit

   SAR: Segmentation And Reassembly

   ULA: Unique Local Address

3.  G.9959 parameters to use for IPv6 transport

   This chapter outlines properties applying to the PHY and MAC of
   G.9959 and how to use these for IPv6 transport.

3.1.  Addressing mode

   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.  NodeIDs are unique within the logical
   network identified by the HomeID.  The logical network identified by
   the HomeID maps directly to an IPv6 subnet identified by one or more
   IPv6 prefixes.

   An IPv6 host SHOULD construct its link-local IPv6 address and
   routable IPv6 addresses from the NodeID in order to facilitate IP
   header compression as described in [RFC6282].

   A word of caution: since HomeIDs and NodeIDs are handed out by a
   network controller function during inclusion, identifier validity and
   uniqueness is limited by the lifetime of the logical network
   membership.  This can be cut short by a mishap occurring to the
   network controller.  Having a single point of failure at the network
   controller suggests that deployers of high-reliability applications
   should carefully consider adding redundancy to the network controller

3.2.  IPv6 Multicast support

   [RFC3819] recommends that IP subnetworks support (subnet-wide)
   multicast.  G.9959 supports direct-range IPv6 multicast while subnet-
   wide multicast is not supported natively by G.9959.  Subnet-wide
   multicast may be provided by an IP routing protocol or a mesh routing
   protocol operating below the 6LoWPAN layer.  Routing protocols are
   out of scope of this document.

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   IPv6 multicast packets MUST be carried via G.9959 broadcast.

   As per [G.9959], this is accomplished as follows:

   1.  The destination HomeID of the G.9959 MAC PDU MUST be the HomeID
       of the logical network

   2.  The destination NodeID of the G.9959 MAC PDU MUST be the
       broadcast NodeID (0xff)

   G.9959 broadcast MAC PDUs are only intercepted by nodes within the
   logical network identified by the HomeID.

3.3.  G.9959 MAC PDU size and IPv6 MTU

   IPv6 packets MUST use G.9959 transmission profiles which support MAC
   PDU payload sizes of 150 bytes or higher, e.g. the R3 profile.
   G.9959 profiles R1 and R2 only supports MPDU payloads around 40 bytes
   and the transmission speed is down to 9.6kbit/s.

   [RFC2460] specifies that IPv6 packets may be up to 1280 octets.
   However, a full IPv6 packet does not fit in an G.9959 MAC PDU.  The
   maximum G.9959 R3 MAC PDU payload size is 158 octets.  Link-layer
   security imposes an overhead, which in the extreme case leaves 130
   octets available.

   G.9959 provides Segmentation And Reassembly for payloads up to 1350
   octets.  Segmentation however adds further overhead.  It is therefore
   desirable that datagrams can fit into a single G.9959 MAC PDU.  IPv6
   Header Compression [RFC6282] improves the chances that a short IPv6
   packet can fit into a single G.9959 frame.

3.4.  Transmission status indications

   The G.9959 MAC layer provides native acknowledgement and
   retransmission of MAC PDUs.  The G.9959 SAR layer does the same for
   larger datagrams.  A mesh routing layer may provide a similar feature
   for routed communication.  Acknowledgment and retransmission improves
   the transmission success rate and frees higher layers from the burden
   of implementing individual retransmission schemes.  An IPv6 routing
   stack communicating over G.9959 may utilize link-layer status
   indications such as delivery confirmation and Ack timeout from the
   MAC layer.

3.5.  Transmission security

   Implementations claiming conformance with this document MUST enable
   G.9959 shared network key security.

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   The shared network key is intended to address security requirements
   in the home at the normal security requirements level.  For
   applications with high or very high requirements on confidentiality
   and/or integrity, additional application layer security measures for
   end-to-end authentication and encryption may need to be applied.  The
   availability of the network relies on the security properties of the
   network key in any case.

4.  LoWPAN Adaptation Layer and Frame Format

   The 6LoWPAN encapsulation formats defined in this chapter are the
   payload in the G.9959 MAC PDU.  IPv6 header compression [RFC6282]
   MUST be supported by implementations of this specification.

   All 6LoWPAN datagrams transported over G.9959 are prefixed by a
   6LoWPAN encapsulation header stack.  The 6LoWPAN payload (e.g. an
   IPv6 packet) follows this encapsulation header.  Each header in the
   header stack contains a header type followed by zero or more header
   fields.  An IPv6 header stack may contain, in the following order,
   addressing, hop-by-hop options, routing, fragmentation, destination
   options, and finally payload [RFC2460].  The 6LoWPAN header format is
   structured the same way.  Currently only payload options are defined
   for the 6LoWPAN header format.

   The definition of 6LoWPAN headers consists of the dispatch value, the
   definition of the header fields that follow, and their ordering
   constraints relative to all other headers.  Although the header stack
   structure provides a mechanism to address future demands on the
   6LoWPAN adaptation layer, it is not intended to provide general
   purpose extensibility.  This document specifies a small set of
   6LoWPAN header types using the 6LoWPAN header stack for clarity,
   compactness, and orthogonality.

4.1.  Dispatch Header

   The dispatch header is shown below:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   | 6LoWPAN CmdCls |   Dispatch    |  Type-specific header         |

                    Figure 1: Dispatch Type and Header

   6LoWPAN CmdCls: 6LoWPAN Command Class identifier.  This field MUST
   carry the value 0x4F [G.9959].  The value specifies that the

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   following bits are a 6LoWPAN encapsulated datagram.  Non-6LoWPAN
   protocols MUST ignore the contents following the 6LoWPAN Command
   Class identifier.

   Dispatch: Identifies the header type immediately following the
   Dispatch Header.

   Type-specific header: A header determined by the Dispatch Header.

   The dispatch value may be treated as an unstructured namespace.  Only
   a few symbols are required to represent current 6LoWPAN
   functionality.  Although some additional savings could be achieved by
   encoding additional functionality into the dispatch byte, these
   measures would tend to constrain the ability to address future

   Dispatch values used in this specification are compatible with the
   dispatch values defined by [RFC4944] and [RFC6282].

   | Pattern    | Header Type                              | Reference |
   | 01  000001 | IPv6        - Uncompressed IPv6 Addresses| [RFC4944] |
   | 01  1xxxxx | 6LoWPAN_IPHC - 6LoWPAN_IPHC compressed IPv6| [RFC6282] |
    All other Dispatch values are unassigned in this document.

                         Figure 2: Dispatch values

   IPv6: Specifies that the following header is an uncompressed IPv6

   6LoWPAN_IPHC: IPv6 Header Compression.  Refer to [RFC6282].

5.  LoWPAN addressing

   IPv6 addresses are autoconfigured from IIDs which are again
   constructed from link-layer address information to save memory in
   devices and to facilitate efficient IP header compression as per

   A G.9959 NodeID is 8 bits in length.  A NodeID is mapped into an IEEE
   EUI-64 identifier as follows:

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   IID = 0000:00ff:fe00:YYXX

                 Figure 3: Constructing a compressible IID

   where XX carries the G.9959 NodeID and YY is a one byte value chosen
   by the individual node.  The default YY value MUST be zero.  A node
   MAY use other values of YY than zero to form additional IIDs in order
   to instantiate multiple IPv6 interfaces.  The YY value MUST be
   ignored when computing the corresponding NodeID (the XX value) from
   an IID.

   A 6LoWPAN network typically is used for M2M-style communication.  The
   method of constructing IIDs from the link-layer address obviously
   does not support addresses assigned or constructed by other means.  A
   node MUST NOT compute the NodeID from the IID if the first 6 bytes of
   the IID do not comply with the format defined in Figure 3.  In that
   case, the address resolution mechanisms of RFC 6775 apply.

5.1.  Stateless Address Autoconfiguration of routable IPv6 addresses

   The IID defined above MUST be used whether autoconfiguring a ULA IPv6
   address [RFC4193] or a globally routable IPv6 address [RFC3587] in
   G.9959 subnets.

5.2.  IPv6 Link Local Address

   The IPv6 link-local address [RFC4291] for a G.9959 interface is
   formed by appending the IID defined above to the IPv6 link local
   prefix FE80::/64.

   The "Universal/Local" (U/L) bit MUST be set to zero in keeping with
   the fact that this is not a globally unique value [EUI64].

   The resulting link local address is formed as follows:

          10 bits            54 bits                  64 bits
       |1111111010|         (zeros)       | Interface Identifier (IID) |

                     Figure 4: IPv6 Link Local Address

5.3.  Unicast Address Mapping

   The address resolution procedure for mapping IPv6 unicast addresses
   into G.9959 link-layer addresses follows the general description in

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   Section 7.2 of [RFC4861].  The Source/Target Link-layer Address
   option MUST have the following form when the link layer is G.9959.

                       0                   1
                       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                      |     Type      |    Length=1   |
                      |     0x00      |    NodeID     |
                      |            Padding            |
                      +-                             -+
                      |          (All zeros)          |

                  Figure 5: IPv6 Unicast Address Mapping

   Option fields:

   Type: The value 1 signifies the Source Link-layer address.  The value
   2 signifies the Destination 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
   always 1 for G.9959 NodeIDs.

   NodeID: This is the G.9959 NodeID the actual interface currently
   responds to.  The link-layer address may change if the interface
   joins another network at a later time.

5.4.  On the use of Neighbor Discovery technologies

   [RFC4861] specifies how IPv6 nodes may resolve link layer addresses
   from IPv6 addresses via the use of link-local IPv6 multicast.
   [RFC6775] is an optimization of [RFC4861], specifically targeting
   6LoWPAN networks.  [RFC6775] defines how a 6LoWPAN node may register
   IPv6 addresses with an authoritative border router (ABR).  Generally,
   nodes SHOULD NOT use [RFC6775] address registration.  However,
   address registration MUST be used if the first 6 bytes of the IID do
   not comply with the format defined in Figure 3.

   In route-over environments, IPv6 hosts MUST use [RFC6775] address
   registration.  [RFC6775] Duplicate Address Detection (DAD) SHOULD NOT
   be used, since the link-layer inclusion process of G.9959 ensures
   that a NodeID is unique for a given HomeID.

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5.4.1.  Prefix and CID management (Route-over)

   A node implementation for route-over operation MAY use RFC6775
   mechanisms for obtaining IPv6 prefixes and corresponding header
   compression context information [RFC6282].  RFC6775 Route-over
   requirements apply with no modifications.

5.4.2.  Prefix and CID management (Mesh-under)

   An implementation for mesh-under operation MUST use [RFC6775]
   mechanisms for managing IPv6 prefixes and corresponding header
   compression context information [RFC6282].  When using [RFC6775]
   mechanisms for sending RAs, the M flag MUST NOT be set.  As stated by
   [RFC6775], an ABR is responsible for managing prefix(es).  Global
   prefixes may change over time.  It is RECOMMENDED that a ULA prefix
   is always assigned to the 6LoWPAN subnet to facilitate stable site-
   local application associations based on IPv6 addresses.  Prefixes
   used in the 6LoWPAN subnet are distributed by normal RA mechanisms.
   The 6LoWPAN Context Option (6CO) is used according to [RFC6775] in an
   RA to disseminate Context IDs (CID) to use for compressing prefixes.
   Prefixes and corresponding Context IDs MUST be assigned during
   initial node inclusion.  Nodes MUST renew the prefix and CID
   according to the lifetime signaled by the ABR.  [RFC6775] specifies
   that the maximum value of the RA Router Lifetime field MAY be up to
   0xFFFF.  This document further specifies that the value 0xFFFF MUST
   be interpreted as infinite lifetime.  This value SHOULD NOT be used
   by ABRs.  Its use is only intended for a sleeping network controller;
   for instance a battery powered remote control being master for a
   small island-mode network of light modules.  CIDs SHOULD be used in a
   cyclic fashion to assist battery powered nodes with no real-time
   clock.  When updating context information, a CID may have its
   lifetime set to zero to obsolete it.  The CID SHOULD NOT be reused
   immediately; rather the next vacant CID should be assigned.  An ABR
   detecting the use of an obsoleted CID SHOULD immediately send an RA
   with updated Context Information.  Header compression based on CIDs
   MUST NOT be used for RA messages carrying Context Information.  An
   expired CID and the associated prefix SHOULD NOT be reset but rather
   retained in receive-only mode if there is no other current need for
   the CID value.  This will allow an ABR to detect if a sleeping node
   without clock uses an expired CID and in response, the LBR SHOULD
   immediately return an RA with fresh Context Information to the
   originator.  Except for the specific redefinition of the RA Router
   Lifetime value 0xFFFF, the above text is in compliance with

6.  Header Compression

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   IPv6 header fields SHOULD be compressed.  If IPv6 header compression
   is used, it MUST be according to [RFC6282].  This section will simply
   identify substitutions that should be made when interpreting the text
   of [RFC6282].

   In general the following substitutions should be made:

   o  Replace "802.15.4" with "G.9959"

   o  Replace "802.15.4 short address" with "<Interface><G.9959 NodeID>"

   o  Replace "802.15.4 PAN ID" with "G.9959 HomeID"

   When a 16-bit address is called for (i.e., an IEEE 802.15.4 "short
   address") it MUST be formed by prepending an Interface label byte to
   the G.9959 NodeID:

                       0                   1
                       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
                      |   Interface   |    NodeID     |

   A transmitting node may be sending to an IPv6 destination address
   which can be reconstructed from the link-layer destination address.
   If the Interface number is zero (the default value), all IPv6 address
   bytes may be elided.  Likewise, the Interface number of a fully
   elided IPv6 address (i.e. SAM/DAM=11) may be reconstructed to the
   value zero by a receiving node.

   64 bit 802.15.4 address details MUST be ignored.  This document only
   specifies the use of short addresses.

7.  IANA Considerations

   This document makes no request of IANA.

   Note to RFC Editor: this section may be removed on publication as an

8.  Security Considerations

   The method of derivation of Interface Identifiers from 8-bit NodeIDs
   preserves uniqueness within the logical network.  However, there is
   no protection from duplication through forgery.  Neighbor Discovery
   in G.9959 links may be susceptible to threats as detailed in
   [RFC3756].  G.9959 networks may feature mesh routing.  This implies

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   additional threats due to ad hoc routing as per [KW03].  G.9959
   provides capability for link-layer security.  G.9959 nodes MUST use
   link-layer security with a shared key.  Doing so will alleviate the
   majority of threats stated above.  A sizeable portion of G.9959
   devices is expected to always communicate within their PAN (i.e.,
   within their subnet, in IPv6 terms).  In response to cost and power
   consumption considerations, these devices will typically implement
   the minimum set of features necessary.  Accordingly, security for
   such devices may rely on the mechanisms defined at the link layer by
   G.9959.  G.9959 relies on the Advanced Encryption Standard (AES) for
   authentication and encryption of G.9959 frames and further employs
   challenge-response handshaking to prevent replay attacks.

   It is also expected that some G.9959 devices (e.g. billing and/or
   safety critical products) will implement coordination or integration
   functions.  These may communicate regularly with IPv6 peers outside
   the subnet.  Such IPv6 devices are expected to secure their end-to-
   end communications with standard security mechanisms (e.g., IPsec,
   TLS, etc).

9.  Acknowledgements

   Thanks to the authors of RFC 4944 and RFC 6282 and members of the
   IETF 6LoWPAN working group; this document borrows extensively from
   their work.  Thanks to Kerry Lynn, Tommas Jess Christensen and Erez
   Ben-Tovim for useful discussions.  Thanks to Carsten Bormann for
   extensive feedback which improved this document significantly.

10.  References

10.1.  Normative References

              REGISTRATION AUTHORITY", IEEE Std http://
              November 2012.

              ITU-T, "G.9959 Contribution: Logical Link Control (LLC)
              layer", ITU-T draft contribution 2013-04-Q15-023.doc,
              April 2013.

              ITU-T, "G.9959 Contribution: Segmentation And Reassembly
              (SAR) adaptation layer", ITU-T draft contribution
              2013-04-Q15-024.doc, April 2013.

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   [G.9959]   ITU-T, "G.9959: Low-Power, narrowband radio for control
              applications", January 2012.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2460]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 2460, December 1998.

   [RFC2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", RFC 2464, December 1998.

   [RFC3587]  Hinden, R., Deering, S., and E. Nordmark, "IPv6 Global
              Unicast Address Format", RFC 3587, August 2003.

   [RFC4193]  Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
              Addresses", RFC 4193, October 2005.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, February 2006.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              September 2007.

   [RFC4941]  Narten, T., Draves, R., and S. Krishnan, "Privacy
              Extensions for Stateless Address Autoconfiguration in
              IPv6", RFC 4941, September 2007.

   [RFC4944]  Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
              "Transmission of IPv6 Packets over IEEE 802.15.4
              Networks", RFC 4944, September 2007.

   [RFC6282]  Hui, J. and P. Thubert, "Compression Format for IPv6
              Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
              September 2011.

   [RFC6775]  Shelby, Z., Chakrabarti, S., Nordmark, E., and C. Bormann,
              "Neighbor Discovery Optimization for IPv6 over Low-Power
              Wireless Personal Area Networks (6LoWPANs)", RFC 6775,
              November 2012.

10.2.  Informative References

   [P2P-RPL]  Goyal, M., Baccelli, E., Philipp, M., Brandt, A., and J.
              Martocci, "IETF, I-D.ietf-roll-p2p-rpl-15, Reactive
              Discovery of Point-to-Point Routes in Low Power and Lossy
              Networks", December 2012.

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Internet-Draft              IPv6 over G.9959                   June 2013

   [RFC3756]  Nikander, P., Kempf, J., and E. Nordmark, "IPv6 Neighbor
              Discovery (ND) Trust Models and Threats", RFC 3756, May

   [RFC3819]  Karn, P., Bormann, C., Fairhurst, G., Grossman, D.,
              Ludwig, R., Mahdavi, J., Montenegro, G., Touch, J., and L.
              Wood, "Advice for Internet Subnetwork Designers", BCP 89,
              RFC 3819, July 2004.

   [RFC6550]  Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R.,
              Levis, P., Pister, K., Struik, R., Vasseur, JP., and R.
              Alexander, "RPL: IPv6 Routing Protocol for Low-Power and
              Lossy Networks", RFC 6550, March 2012.

Authors' Addresses

   Anders Brandt
   Sigma Designs
   Emdrupvej 26A, 1.
   Copenhagen O  2100

   Email: anders_brandt@sigmadesigns.com

   Jakob Buron
   Sigma Designs
   Emdrupvej 26A, 1.
   Copenhagen O  2100

   Email: jakob_buron@sigmadesigns.com

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