draft-ietf-lwig-6lowpan-virtual-reassembly-01.txt		draft-ietf-lwig-6lowpan-virtual-reassembly-02.txt
	Network Working Group C. Bormann		Network Working Group C. Bormann
	Internet-Draft Universitaet Bremen TZI		Internet-Draft Universitaet Bremen TZI
	Intended status: Informational T. Watteyne		Intended status: Informational T. Watteyne
	Expires: September 12, 2019 Analog Devices		Expires: September 10, 2020 Analog Devices
	March 11, 2019		March 09, 2020
	Virtual reassembly buffers in 6LoWPAN		Virtual reassembly buffers in 6LoWPAN
	draft-ietf-lwig-6lowpan-virtual-reassembly-01		draft-ietf-lwig-6lowpan-virtual-reassembly-02
	Abstract		Abstract
	When employing adaptation layer fragmentation in 6LoWPAN, it may be		When employing adaptation layer fragmentation in 6LoWPAN, it may be
	beneficial for a forwarder not to have to reassemble each packet in		beneficial for a forwarder not to have to reassemble each packet in
	its entirety before forwarding it.		its entirety before forwarding it.
	This has been always possible with the original fragmentation design		This has been always possible with the original fragmentation design
	of RFC 4944. Apart from a brief mention of the way to do this in		of RFC 4944. Apart from a brief mention of the way to do this in
	Section 2.5.2 of the 6LoWPAN book, this has not been extensively		Section 2.5.2 of the 6LoWPAN book, this has not been extensively
	skipping to change at page 1, line 39 ¶		skipping to change at page 1, line 39 ¶
	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 https://datatracker.ietf.org/drafts/current/.		Drafts is at https://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 September 12, 2019.		This Internet-Draft will expire on September 10, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2020 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
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://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
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Reassembly buffers . . . . . . . . . . . . . . . . . . . . . 3		2. Reassembly buffers . . . . . . . . . . . . . . . . . . . . . 3
	3. Virtual reassembly . . . . . . . . . . . . . . . . . . . . . 3		3. Virtual reassembly . . . . . . . . . . . . . . . . . . . . . 3
	4. Header compression . . . . . . . . . . . . . . . . . . . . . 4		4. Header compression . . . . . . . . . . . . . . . . . . . . . 4
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
	6. Security considerations . . . . . . . . . . . . . . . . . . . 4		6. Security considerations . . . . . . . . . . . . . . . . . . . 4
	7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4		7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
	7.1. Normative References . . . . . . . . . . . . . . . . . . 4		7.1. Normative References . . . . . . . . . . . . . . . . . . 5
	7.2. Informative References . . . . . . . . . . . . . . . . . 5		7.2. Informative References . . . . . . . . . . . . . . . . . 5
	Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 5		Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 5
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
	1. Introduction		1. Introduction
	6LoWPAN [RFC4944] is the seminal standard for the transmission of		6LoWPAN [RFC4944] is the seminal standard for the transmission of
	IPv6 packets over IEEE 802.15.4 networks and has served as a		IPv6 packets over IEEE 802.15.4 networks and has served as a
	blueprint for a number of related standards addressing low-power		blueprint for a number of related standards addressing low-power
	radios and other IoT connectivity solutions (the "6Lo suite").		radios and other IoT connectivity solutions (the "6Lo suite").
	skipping to change at page 2, line 48 ¶		skipping to change at page 2, line 48 ¶
	When employing adaptation layer fragmentation on constrained-node		When employing adaptation layer fragmentation on constrained-node
	networks [RFC7228], it may be beneficial for a forwarder not to have		networks [RFC7228], it may be beneficial for a forwarder not to have
	to reassemble each packet in its entirety before forwarding it.		to reassemble each packet in its entirety before forwarding it.
	This has been always possible with the original fragmentation design		This has been always possible with the original fragmentation design
	of RFC 4944. Apart from a brief mention of the way to do this in		of RFC 4944. Apart from a brief mention of the way to do this in
	Section 2.5.2 of the 6LoWPAN book [BOOK], this has not been		Section 2.5.2 of the 6LoWPAN book [BOOK], this has not been
	extensively described in the literature. The present document		extensively described in the literature. The present document
	attempts to fill that gap.		attempts to fill that gap.
	[I-D.watteyne-6lo-minimal-fragment] provides additional context and		[I-D.ietf-6lo-minimal-fragment] provides additional context and
	discussion about handling fragment forwarding in the 6Lo standards		discussion about handling fragment forwarding in the 6Lo standards
	suite.		suite.
	2. Reassembly buffers		2. Reassembly buffers
	An adaptation layer implementation for 6LoWPAN needs to perform		An adaptation layer implementation for 6LoWPAN needs to perform
	reassembly of every fragmented packet received in order to be able to		reassembly of every fragmented packet received in order to be able to
	forward the packet (re-fragmenting it in the process).		forward the packet (re-fragmenting it in the process).
	A reassembly buffer for 6LoWPAN contains:		A reassembly buffer for 6LoWPAN contains:
	skipping to change at page 4, line 43 ¶		skipping to change at page 4, line 43 ¶
	here.) This makes sure an additional fragment only needs to be sent		here.) This makes sure an additional fragment only needs to be sent
	if the header expansion during forwarding would have created an		if the header expansion during forwarding would have created an
	additional fragment with full reassembly as well.		additional fragment with full reassembly as well.
	5. IANA Considerations		5. IANA Considerations
	This document makes no requests of IANA.		This document makes no requests of IANA.
	6. Security considerations		6. Security considerations
	TBD		There are many security considerations with using fragmentation in
			the first place, even with adaptation layer fragmentation (which is
			not accessible outside the range of that adaptation layer). Some of
			the more specific ones are documented in
			[I-D.ietf-6lo-minimal-fragment] and will not be duplicated here.
			In general, sending on fragments early from a node will relieve the
			node that is doing the forwarding, but put additional onus on the
			next node. This may or may not be in favor of an attacker.
	7. References		7. References
	7.1. Normative References		7.1. Normative References
	[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,		[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
	"Transmission of IPv6 Packets over IEEE 802.15.4		"Transmission of IPv6 Packets over IEEE 802.15.4
	Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007,		Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007,
	<https://www.rfc-editor.org/info/rfc4944>.		<https://www.rfc-editor.org/info/rfc4944>.
	7.2. Informative References		7.2. Informative References
	[BOOK] Shelby, Z. and C. Bormann, "6LoWPAN", John Wiley & Sons,		[BOOK] Shelby, Z. and C. Bormann, "6LoWPAN", John Wiley & Sons,
	Ltd monograph, DOI 10.1002/9780470686218, November 2009.		Ltd monograph, DOI 10.1002/9780470686218, November 2009.
	[I-D.watteyne-6lo-minimal-fragment]		[I-D.ietf-6lo-minimal-fragment]
	Watteyne, T., Bormann, C., and P. Thubert, "LLN Minimal		Watteyne, T., Thubert, P., and C. Bormann, "On Forwarding
	Fragment Forwarding", draft-watteyne-6lo-minimal-		6LoWPAN Fragments over a Multihop IPv6 Network", draft-
	fragment-02 (work in progress), July 2018.		ietf-6lo-minimal-fragment-14 (work in progress), March
			2020.
	[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6		[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
	Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,		Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
	DOI 10.17487/RFC6282, September 2011,		DOI 10.17487/RFC6282, September 2011,
	<https://www.rfc-editor.org/info/rfc6282>.		<https://www.rfc-editor.org/info/rfc6282>.
	[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for		[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
	Constrained-Node Networks", RFC 7228,		Constrained-Node Networks", RFC 7228,
	DOI 10.17487/RFC7228, May 2014,		DOI 10.17487/RFC7228, May 2014,
	<https://www.rfc-editor.org/info/rfc7228>.		<https://www.rfc-editor.org/info/rfc7228>.
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