draft-ietf-6lowpan-hc-10.txt   draft-ietf-6lowpan-hc-11.txt 
Network Working Group J. Hui, Ed. Network Working Group J. Hui, Ed.
Internet-Draft Arch Rock Corporation Internet-Draft Arch Rock Corporation
Updates: 4944 (if approved) P. Thubert Updates: 4944 (if approved) P. Thubert
Intended status: Standards Track Cisco Intended status: Standards Track Cisco
Expires: March 4, 2011 August 31, 2010 Expires: March 5, 2011 September 1, 2010
Compression Format for IPv6 Datagrams in 6LoWPAN Networks Compression Format for IPv6 Datagrams in 6LoWPAN Networks
draft-ietf-6lowpan-hc-10 draft-ietf-6lowpan-hc-11
Abstract Abstract
This document specifies an IPv6 header compression format for IPv6 This document specifies an IPv6 header compression format for IPv6
packet delivery in 6LoWPAN networks. The compression format relies packet delivery in 6LoWPAN networks. The compression format relies
on shared context to allow compression of arbitrary prefixes. How on shared context to allow compression of arbitrary prefixes. How
the information is maintained in that shared context is out of scope. the information is maintained in that shared context is out of scope.
This document specifies compression of multicast addresses and a This document specifies compression of multicast addresses and a
framework for compressing next headers. UDP header compression is framework for compressing next headers. UDP header compression is
specified within this framework. specified within this framework.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 4, 2011. This Internet-Draft will expire on March 5, 2011.
Copyright Notice Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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3.2.4. Stateful Multicast Address Compression . . . . . . . . 13 3.2.4. Stateful Multicast Address Compression . . . . . . . . 13
4. IPv6 Next Header Compression . . . . . . . . . . . . . . . . . 13 4. IPv6 Next Header Compression . . . . . . . . . . . . . . . . . 13
4.1. LOWPAN_NHC Format . . . . . . . . . . . . . . . . . . . . 14 4.1. LOWPAN_NHC Format . . . . . . . . . . . . . . . . . . . . 14
4.2. IPv6 Extension Header Compression . . . . . . . . . . . . 14 4.2. IPv6 Extension Header Compression . . . . . . . . . . . . 14
4.3. UDP Header Compression . . . . . . . . . . . . . . . . . . 16 4.3. UDP Header Compression . . . . . . . . . . . . . . . . . . 16
4.3.1. Compressing UDP ports . . . . . . . . . . . . . . . . 16 4.3.1. Compressing UDP ports . . . . . . . . . . . . . . . . 16
4.3.2. Compressing UDP checksum . . . . . . . . . . . . . . . 16 4.3.2. Compressing UDP checksum . . . . . . . . . . . . . . . 16
4.3.3. UDP LOWPAN_NHC Format . . . . . . . . . . . . . . . . 17 4.3.3. UDP LOWPAN_NHC Format . . . . . . . . . . . . . . . . 17
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
6. Security Considerations . . . . . . . . . . . . . . . . . . . 19 6. Security Considerations . . . . . . . . . . . . . . . . . . . 19
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 20
8. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 8. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 22
9.1. Normative References . . . . . . . . . . . . . . . . . . . 21 9.1. Normative References . . . . . . . . . . . . . . . . . . . 22
9.2. Informative References . . . . . . . . . . . . . . . . . . 22 9.2. Informative References . . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction 1. Introduction
The [IEEE 802.15.4] standard specifies an MTU of 127 bytes, yielding The [IEEE 802.15.4] standard specifies an MTU of 127 bytes, yielding
about 80 octets of actual MAC payload with security enabled, on a about 80 octets of actual MAC payload with security enabled, on a
wireless link with a link throughput of 250 kbps or less. The wireless link with a link throughput of 250 kbps or less. The
6LoWPAN adaptation format [RFC4944] was specified to carry IPv6 6LoWPAN adaptation format [RFC4944] was specified to carry IPv6
datagrams over such constrained links, taking into account limited datagrams over such constrained links, taking into account limited
bandwidth, memory, or energy resources that are expected in bandwidth, memory, or energy resources that are expected in
applications such as wireless sensor networks. [RFC4944] defines a applications such as wireless sensor networks. [RFC4944] defines a
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zero to indicate local scope. zero to indicate local scope.
This mapping for non-EUI-64 identifiers differs from that presented This mapping for non-EUI-64 identifiers differs from that presented
in Appendix A of [RFC4291]. Using the restricted space ensures no in Appendix A of [RFC4291]. Using the restricted space ensures no
overlap with IIDs generated from unrestricted IEEE EUI-64 addresses. overlap with IIDs generated from unrestricted IEEE EUI-64 addresses.
Also, including 0xfffe in the middle of the IID helps avoid overlap Also, including 0xfffe in the middle of the IID helps avoid overlap
with other locally managed IIDs. with other locally managed IIDs.
This mapping from a short IEEE 802.15.4 address to 64-bit IIDs is This mapping from a short IEEE 802.15.4 address to 64-bit IIDs is
also used to reconstruct any part of an IID not covered by context also used to reconstruct any part of an IID not covered by context
information when only 16 bits are carried in-line (SAC/DAC=10). information.
3.2.3. Stateless Multicast Address Compression 3.2.3. Stateless Multicast Address Compression
LOWPAN_IPHC supports stateless compression of multicast addresses LOWPAN_IPHC supports stateless compression of multicast addresses
when M = 1 and DAC = 0. An IPv6 multicast address may be compressed when M = 1 and DAC = 0. An IPv6 multicast address may be compressed
down to 48, 32, or 8 bits using stateless compression. The format down to 48, 32, or 8 bits using stateless compression. The format
supports compression of the Solicited-Node Multicast Address (FF02:: supports compression of the Solicited-Node Multicast Address (FF02::
1:FFXX:XXXX) as well as any IPv6 multicast address where the upper 1:FFXX:XXXX) as well as any IPv6 multicast address where the upper
bits of the multicast group identifier are zero. The 8-bit bits of the multicast group identifier are zero. The 8-bit
compressed form only carries the least-significant bits of the compressed form only carries the least-significant bits of the
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Thanks to Julien Abeille, Robert Assimiti, Dominique Barthel, Carsten Thanks to Julien Abeille, Robert Assimiti, Dominique Barthel, Carsten
Bormann, Robert Cragie, Stephen Dawson-Haggerty, Mathilde Durvy, Erik Bormann, Robert Cragie, Stephen Dawson-Haggerty, Mathilde Durvy, Erik
Nordmark, Christos Polyzois, Shoichi Sakane, Zach Shelby, Dario Nordmark, Christos Polyzois, Shoichi Sakane, Zach Shelby, Dario
Tedeschi, Tony Viscardi, and Jay Werb for useful design consideration Tedeschi, Tony Viscardi, and Jay Werb for useful design consideration
and implementation feedback. and implementation feedback.
8. Changes 8. Changes
(This section to be removed by the RFC editor.) (This section to be removed by the RFC editor.)
Draft 11:
- Removed incorrect and unnecessary text in specifying how to
derive the IID bits not covered by the context.
- Adjust formatting to reduce orphans and widows..
Draft 10: Draft 10:
- Specify that the IID has the form 0000:00ff:fe00:XXXX when SAC/ - Specify that the IID has the form 0000:00ff:fe00:XXXX when SAC/
DAC=0 and SAM/DAM=10. DAC=0 and SAM/DAM=10.
Draft 09: Draft 09:
- Indicate that a mechanism to learn decompressor's capabilities - Indicate that a mechanism to learn decompressor's capabilities
to decode additional (future) NHCs is out of scope. to decode additional (future) NHCs is out of scope.
- Clarify how to derive IID bits not covered by the context when - Clarify how to derive IID bits not covered by the context when
only 16 bits are carried inline. only 16 bits are carried inline.
- Clarify the value of the Length field for compressed extension - Clarify the value of the Length field for compressed extension
 End of changes. 7 change blocks. 
9 lines changed or deleted 14 lines changed or added

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