Internet DRAFT - draft-popa-6lo-6loplc-ipv6-over-ieee19012-networks
draft-popa-6lo-6loplc-ipv6-over-ieee19012-networks
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
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This Internet-Draft will expire on September 30, 2014.
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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.
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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
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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]
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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
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