6lo Working Group                                           D. Popa, Ed.
Internet-Draft                                               Itron, Inc.
Updates: RFC 4944 and RFC 6282 (if approved)                    J.H. Hui
Intended status: Standards Track                                   Cisco
Expires: September 30, 2014                               March 31, 2014

    6LoPLC: Transmission of IPv6 Packets over IEEE 1901.2 Narrowband
                    Powerline Communication Networks
       draft-popa-6lo-6loplc-ipv6-over-ieee19012-networks-00.txt

Abstract

   This document updates [RFC 4944], "Transmission of IPv6 Packets over
   IEEE 802.15.4 Networks", and [RFC 6282], "Compression Format for IPv6
   Datagrams over IEEE 802.15.4-Based Networks", and specifies the
   6LoPLC technology: the transmission of IPv6 packets over IEEE 1901.2
   narrowband powerline communication networks.

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 September 30, 2014.

Copyright Notice

   Copyright (c) 2014 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 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.





Popa & Hui             Expires September 30, 2014               [Page 1]


Internet-Draft                   6LoPLC                       March 2014

1.  Introduction

   6LOWPAN technology defines the transport of IPv6 packets over IEEE
   802.15.4-2006 low power and lossy networks (LLNs). Because the
   802.15.4-2006 wireless links do not support the IPv6 requirement for
   a link MTU of at least 1280 octets, 6LOWPAN adaptation layer defines
   header compression and fragmentation of IPv6 packets.

   A link in a LLN is characterized as lossy, low-power, low bit-rate,
   and short range.  The LLN nodes have resources constrained in terms
   of processing power, memory capabilities, and communication
   bandwidth, due to a combination of factors including regulations on
   spectrum use, form factor and cost considerations.

   Recently, IEEE Standard Association published the IEEE 1901.2 PHY and
   MAC standard for narrowband powerline communications (NB-PLC). When
   used in LLNs, apart from using powerline communications instead of
   wireless communications, the devices implementing IEEE 1901.2
   standard share the same constraints as their wireless counterparts.

1.1.  Applicability

   This document updates [RFC4944] and [RFC6282] and specifies 6LoPLC:
   the transmission of IPv6 packets over IEEE 1901.2 NB-PLC networks.

   The term 6LoPLC is used to make a clear difference between the
   6LOWPAN technology, known in the industry as a mechanism to transmit
   IPv6 packets over 802.15.4-2006 wireless networks, and the use of
   6LOWPAN technology for the transmission of IPv6 packets over IEEE
   1901.2 networks.

   This document specifies a set of behaviors between devices in 1901.2
   networks, which apply to both mesh and star topologies.  An
   implementation that adheres to this document MUST implement these
   behaviors.

1.2.  IEEE 1901.2 Technology

   This section describes those features from IEEE 1901.2 standard that
   are relevant to the transmission of IPv6 packets over 1901.2
   networks.  For further details on IEEE 1901.2 technology, the reader
   is invited to refer to [IEEE1901.2].

   IEEE 1901.2 standard defines a Narrowband PLC PHY and MAC technology
   for indoor and outdoor communications (e.g., smart grid networks,
   home area networks).

   IEEE 1901.2 MAC frame format endorses the IEEE 802.15.4-2006 MAC
   frame format [IEEE802.15.4], with a few exceptions described below.






Popa & Hui             Expires September 30, 2014               [Page 2]


Internet-Draft                   6LoPLC                       March 2014


   o  The IEEE 1901.2 MAC frame format is obtained by prepending a
      Segment Control Field to the IEEE 802.15.4-2006 MAC frame.  One
      function of the Segment Control Field is to carry inline
      information for the MAC sub-layer fragmentation and reassembly
      process.  Note that the complete format and use of Segment Control
      Field are not relevant to the transmission of IPv6 packets over
      IEEE 1901.2 networks.

   o  IEEE 1901.2 MAC frame format endorses only the IEEE 802.15.4-2006
      short and extended MAC addresses with a length of 16 and 64 bits,
      respectively.

   o  IEEE 1901.2 MAC frame format endorses the concept of Information
      Elements, as defined in IEEE 802.15.4e-2012 [IEEE802.15.4e].  Note
      that the format and use of Information Elements are not relevant
      to the transmission of IPv6 packets over IEEE 1901.2 networks.

   The maximum size of a 1901.2 MAC frame payload is 1280 bytes, while
   the maximum size of a 1901.2 PHY frame payload is 512 bytes.  The PHY
   frame payload size can vary from frame to frame, as a function of the
   modulation used to transmit the frame and the strength of the Forward
   Error Correction scheme.

   To cope with the mismatch between the size of the PHY frame payload
   and the size of the MAC frame, the IEEE 1901.2 standard specifies a
   mandatory MAC sub-layer fragmentation and reassembly process.  This
   process fragments an upper layer datagram into multiple fragments and
   provides a reliable one-hop transfer of the resulting fragments.

2.  Transmission of IPv6 Packets over IEEE 1901.2 Networks

   The transmission of IPv6 packets over low-power and lossy networks
   relies on two mechanisms defined at 6LOWPAN adaptation layer.  The
   first mechanism defines a set of procedures for IPv6 and UDP header
   compression (as specified in [RFC4944] and updated in [RFC6282]).
   The second mechanism defines a scheme for one-hop fragmentation and
   reassembly of IPv6 packets (as specified in [RFC4944]).

2.1.  6LOWPAN Header compression

   Because IEEE 1901.2 fundamentally supports the IEEE 802.15.4-2006 MAC
   frame format and addressing scheme, IEEE 1901.2 devices implementing
   this specification MUST support the 6LOWPAN header compression
   schemes specified in [RFC6282].

   Note that header compression mechanisms defined in [RFC6282]
   completely replace the header compression mechanisms defined in
   [RFC4944].

2.2.  6LOWPAN Fragmentation




Popa & Hui             Expires September 30, 2014               [Page 3]


Internet-Draft                   6LoPLC                       March 2014


   The use of fragmentation and reassembly consumes resources in terms
   of buffering and processing power.  Also, fragmentation and
   reassembly consumes link capacity because, for each fragment that is
   transmitted, additional headers are required to properly manage the
   transmission, retransmission and reassembly of the fragments.  As
   such, in the context of LLNs, where HW resources are constrained and
   network capacity is scarce, the fragmentation and reassembly should
   be avoided whenever possible.

   Because IEEE 1901.2 fundamentally supports a MAC payload of 1280
   bytes and provides its own MAC sub-layer fragmentation mechanism, the
   use of 6LOWPAN fragmentation scheme defined in [RFC4944], when
   transmitting IPv6 packets over IEEE 1901.2 networks, is NOT
   RECOMMENDED.

3.  IANA Considerations

   No IANA considerations.

4.  Security Considerations

   This document has no security considerations beyond those in
   [RFC4291].

5.  Acknowledgements

   The authors would like to acknowledge the review, feedback, and
   comments of Matthew Gillmore, Samita Chakrabarti, and Ulrich Herberg.

6.  References

6.1.  Normative References

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

   [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.

6.2.  Informative References

   [IEEE1901.2]
              IEEE SA , "IEEE Standard for Low-Frequency (less than 500
              kHz) Narrowband Power Line Communications for Smart Grid
              Applications", December 2013.

   [IEEE802.15.4]


Popa & Hui             Expires September 30, 2014               [Page 4]


Internet-Draft                   6LoPLC                       March 2014

              IEEE SA, "IEEE Standard for Information technology-- Local
              and metropolitan area networks-- Specific requirements--
              Part 15.4: Wireless Medium Access Control (MAC) and
              Physical Layer (PHY) Specifications for Low Rate Wireless
              Personal Area Networks (WPANs)", September 2006.

   [IEEE802.15.4e]
              IEEE SA , "IEEE Standard for Local and metropolitan area
              networks--Part 15.4: Low-Rate Wireless Personal Area
              Networks (LR-WPANs) Amendment 1: MAC sublayer", April
              2012.

Authors' Addresses

   Daniel Popa, editor
   Itron, Inc.
   52, rue Camille Desmoulins
   Issy les Moulineaux, 92130
   FR
   
   Email: daniel.popa@itron.com


   Jonathan W. Hui
   Cisco
   170 West Tasman Drive
   San Jose, California 95134
   USA
   
   Phone: +408 424 1547
   Email: jonhui@cisco.com























Popa & Hui             Expires September 30, 2014               [Page 5]