draft-ietf-tcpm-alternativebackoff-ecn-08.txt		draft-ietf-tcpm-alternativebackoff-ecn-09.txt
	Network Working Group N. Khademi		Network Working Group N. Khademi
	Internet-Draft M. Welzl		Internet-Draft M. Welzl
	Intended status: Experimental University of Oslo		Intended status: Experimental University of Oslo
	Expires: February 8, 2019 G. Armitage		Expires: February 15, 2019 G. Armitage
	Netflix		Netflix
	G. Fairhurst		G. Fairhurst
	University of Aberdeen		University of Aberdeen
	August 7, 2018		August 14, 2018
	TCP Alternative Backoff with ECN (ABE)		TCP Alternative Backoff with ECN (ABE)
	draft-ietf-tcpm-alternativebackoff-ecn-08		draft-ietf-tcpm-alternativebackoff-ecn-09
	Abstract		Abstract
	Active Queue Management (AQM) mechanisms allow for burst tolerance		Active Queue Management (AQM) mechanisms allow for burst tolerance
	while enforcing short queues to minimise the time that packets spend		while enforcing short queues to minimise the time that packets spend
	enqueued at a bottleneck. This can cause noticeable performance		enqueued at a bottleneck. This can cause noticeable performance
	degradation for TCP connections traversing such a bottleneck,		degradation for TCP connections traversing such a bottleneck,
	especially if there are only a few flows or their bandwidth-delay-		especially if there are only a few flows or their bandwidth-delay-
	product is large. The reception of a Congestion Experienced (CE) ECN		product is large. The reception of a Congestion Experienced (CE) ECN
	mark indicates that an AQM mechanism is used at the bottleneck, and		mark indicates that an AQM mechanism is used at the bottleneck, and
	skipping to change at page 1, line 47 ¶		skipping to change at page 1, line 47 ¶
	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 February 8, 2019.		This Internet-Draft will expire on February 15, 2019.
	Copyright Notice		Copyright Notice
	Copyright (c) 2018 IETF Trust and the persons identified as the		Copyright (c) 2018 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
	skipping to change at page 4, line 23 ¶		skipping to change at page 4, line 23 ¶
	The TCP sender response is currently specified in section 6.1.2 of		The TCP sender response is currently specified in section 6.1.2 of
	the ECN specification [RFC3168], updated by [RFC8311]:		the ECN specification [RFC3168], updated by [RFC8311]:
	The indication of congestion should be treated just as a		The indication of congestion should be treated just as a
	congestion loss in non-ECN-Capable TCP. That is, the TCP source		congestion loss in non-ECN-Capable TCP. That is, the TCP source
	halves the congestion window "cwnd" and reduces the slow start		halves the congestion window "cwnd" and reduces the slow start
	threshold "ssthresh", unless otherwise specified by an		threshold "ssthresh", unless otherwise specified by an
	Experimental RFC in the IETF document stream.		Experimental RFC in the IETF document stream.
	This is replaced with:		Following publication of RFC8311, this document specifies a sender-
			side change to TCP:
	Receipt of a packet with the ECN-Echo flag SHOULD trigger the TCP		Receipt of a packet with the ECN-Echo flag SHOULD trigger the TCP
	source to set the slow start threshold (ssthresh) to 0.8 times the		source to set the slow start threshold (ssthresh) to 0.8 times the
	FlightSize, with a lower bound of 2 * SMSS applied to the result.		FlightSize, with a lower bound of 2 * SMSS applied to the result.
	As in [RFC5681], the TCP sender also reduces the cwnd value to no		As in [RFC5681], the TCP sender also reduces the cwnd value to no
	more than the new ssthresh value. RFC 3168 section 6.1.2 provides		more than the new ssthresh value. RFC 3168 section 6.1.2 provides
	guidance on setting a cwnd less than 2 * SMSS.		guidance on setting a cwnd less than 2 * SMSS.
	3.1. Choice of ABE Multiplier		3.1. Choice of ABE Multiplier
	skipping to change at page 9, line 41 ¶		skipping to change at page 9, line 41 ¶
	mechanisms that have been in use in the Internet for many years		mechanisms that have been in use in the Internet for many years
	(e.g., CUBIC [RFC8312]). Unfairness may also be a result of other		(e.g., CUBIC [RFC8312]). Unfairness may also be a result of other
	factors, including the round trip time experienced by a flow. ABE		factors, including the round trip time experienced by a flow. ABE
	applies only when ECN-marked packets are received, not when packets		applies only when ECN-marked packets are received, not when packets
	are lost, hence use of ABE cannot lead to congestion collapse.		are lost, hence use of ABE cannot lead to congestion collapse.
	11. Revision Information		11. Revision Information
	XX RFC ED - PLEASE REMOVE THIS SECTION XXX		XX RFC ED - PLEASE REMOVE THIS SECTION XXX
			-09. Chnaged to "Following publication of RFC8311, this document
			specifies a sender-side change to TCP:"
	-08. Addressed comments from AD review on the document structure,		-08. Addressed comments from AD review on the document structure,
	and relationship to existing RFCs.		and relationship to existing RFCs.
	-07. Addressed comments following WGLC.		-07. Addressed comments following WGLC.
	o Updated Reference citations.		o Updated Reference citations.
	o Removed paragraph containing a wrong statement related to timeout		o Removed paragraph containing a wrong statement related to timeout
	in section 4.1.		in section 4.1.
End of changes. 6 change blocks.
	5 lines changed or deleted		9 lines changed or added
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