draft-ietf-roll-trickle-00.txt		draft-ietf-roll-trickle-01.txt
	Networking Working Group P. Levis		Networking Working Group P. Levis
	Internet-Draft Stanford University		Internet-Draft Stanford University
	Intended status: Informational T. Clausen		Intended status: Informational T. Clausen
	Expires: September 24, 2010 LIX, Ecole Polytechnique		Expires: October 12, 2010 LIX, Ecole Polytechnique
	March 23, 2010		J. Hui
			Arch Rock Corporation
			J. Ko
			Johns Hopkins University
			April 10, 2010
	The Trickle Algorithm		The Trickle Algorithm
	draft-ietf-roll-trickle-00		draft-ietf-roll-trickle-01
	Abstract		Abstract
	The Trickle algorithm allows wireless nodes to exchange information		The Trickle algorithm allows wireless nodes to exchange information
	in a highly robust, energy efficient, simple, and scalable manner.		in a highly robust, energy efficient, simple, and scalable manner.
	Dynamically adjusting transmission windows allows Trickle to spread		Dynamically adjusting transmission windows allows Trickle to spread
	new information on the scale of link-layer transmission times while		new information on the scale of link-layer transmission times while
	sending only a few messages per hour when information does not		sending only a few messages per hour when information does not
	change. A simple suppression nechanism and transmission point		change. A simple suppression nechanism and transmission point
	selection allows Trickle's communication rate to scale		selection allows Trickle's communication rate to scale
	skipping to change at page 1, line 45		skipping to change at page 1, line 49
	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."
	The list of current Internet-Drafts can be accessed at		The list of current Internet-Drafts can be accessed at
	http://www.ietf.org/ietf/1id-abstracts.txt.		http://www.ietf.org/ietf/1id-abstracts.txt.
	The list of Internet-Draft Shadow Directories can be accessed at		The list of Internet-Draft Shadow Directories can be accessed at
	http://www.ietf.org/shadow.html.		http://www.ietf.org/shadow.html.
	This Internet-Draft will expire on September 24, 2010.		This Internet-Draft will expire on October 12, 2010.
	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
	skipping to change at page 5, line 44		skipping to change at page 5, line 44
	2. Whenever Trickle hears a transmission that is "consistent," it		2. Whenever Trickle hears a transmission that is "consistent," it
	increments counter c.		increments counter c.
	3. At time t, Trickle transmits if and only if counter c is less		3. At time t, Trickle transmits if and only if counter c is less
	than the redundancy constant k.		than the redundancy constant k.
	4. When an interval expires, Trickle doubles the interval length.		4. When an interval expires, Trickle doubles the interval length.
	If this new interval length would be longer than Imax, Trickle		If this new interval length would be longer than Imax, Trickle
	sets the interval length I to be Imax.		sets the interval length I to be Imax.
	5. If Trickle hears a transmission that is "inconsistent" and I is		5. If Trickle hears a transmission that is "inconsistent," the
	greater than Imin, Trickle resets I to Imin, and begins a new		Trickle timer resets. If I is greater than Imin, resetting a
	interval.		Trickle timer sets I to Imin and begins a new interval. If is
			equal to Imin, resetting a Trickle timer does nothing. Trickle
			may also reset the timer in response to external "events."
	The terms consistent and inconsistent are in quotes because their		The terms consistent, inconsistent and event are in quotes because
	meaning depends on the use of Trickle.		their meaning depends on the use of Trickle.
	5. Using Trickle		5. Using Trickle
	A protocol specification that uses Trickle should specify:		A protocol specification that uses Trickle MUST specify:
	o Default values for Imin, Imax, and k. Because link layers can		o Default values for Imin, Imax, and k. Because link layers can
	vary widely in their properties, the default value of Imin should		vary widely in their properties, the default value of Imin should
	be specified in terms of the worst-case latency of a link layer		be specified in terms of the worst-case latency of a link layer
	transmission. For example, a specification should say "the		transmission. For example, a specification should say "the
	default value of Imin is 4 times the worst case link layer		default value of Imin is 4 times the worst case link layer
	latency" and should not say "the default value of Imin is 500		latency" and should not say "the default value of Imin is 500
	milliseconds." Worst case latency is the time until the first		milliseconds." Worst case latency is the time until the first
	link-layer transmission of the frame assuming an idle channel		link-layer transmission of the frame assuming an idle channel
	(does not include backoff, virtual carrier sense, etc.).		(does not include backoff, virtual carrier sense, etc.).
	o What constitutes a "consistent" transmission.		o What constitutes a "consistent" transmission.
	o What constitutes an "inconsistent" transmission.		o What constitutes an "inconsistent" transmission.
			o Any "events" besides inconsistent transmissions that reset the
			Trickle timer.
	6. Operational Considerations		6. Operational Considerations
	It is RECOMMENDED that a protocol which uses Trickle include		It is RECOMMENDED that a protocol which uses Trickle include
	mechanisms to inform nodes of configuration parameters at runtime.		mechanisms to inform nodes of configuration parameters at runtime.
	However, it is not always possible to do so. In the cases where		However, it is not always possible to do so. In the cases where
	different nodes have different configuration parameters, Trickle may		different nodes have different configuration parameters, Trickle may
	have unintended behaviors. This section outlines some of those		have unintended behaviors. This section outlines some of those
	behaviors as an educational exercise.		behaviors as an educational exercise.
	6.1. Mismatched redundancy constants		6.1. Mismatched redundancy constants
	skipping to change at line 336		skipping to change at page 8, line 30
	USA		USA
	Phone: +1 650 725 9064		Phone: +1 650 725 9064
	Email: pal@cs.stanford.edu		Email: pal@cs.stanford.edu
	Thomas Heide Clausen		Thomas Heide Clausen
	LIX, Ecole Polytechnique		LIX, Ecole Polytechnique
	Phone: +33 6 6058 9349		Phone: +33 6 6058 9349
	Email: T.Clausen@computer.org		Email: T.Clausen@computer.org
			Jonathan Hui
			Arch Rock Corporation
			501 Snd St., Suite 410
			San Francisco, CA 94107
			USA
			Email: jhui@archrock.com
			JeongGil Ko
			Johns Hopkins University
			3100 Wyman Park Dr., Room 414
			Baltimore, MD 21211
			USA
			Phone: +1 410 516 4312
			Email: jgko@cs.jhu.edu
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