< draft-irtf-tmrg-tools-04.txt		draft-irtf-tmrg-tools-05.txt >
	Internet Engineering Task Force S. Floyd		Internet Engineering Task Force S. Floyd
	INTERNET-DRAFT E. Kohler		INTERNET-DRAFT E. Kohler
	Intended status: Informational Editors		Intended status: Informational Editors
	Expires: January 2008 8 July 2007		Expires: August 2008 23 February 2008
	Tools for the Evaluation of Simulation and Testbed Scenarios		Tools for the Evaluation of Simulation and Testbed Scenarios
	draft-irtf-tmrg-tools-04.txt		draft-irtf-tmrg-tools-05.txt
	Status of this Memo		Status of this Memo
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	skipping to change at page 1, line 33 ¶		skipping to change at page 1, line 33 ¶
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	Abstract		Abstract
	This document describes tools for the evaluation of simulation and		This document describes tools for the evaluation of simulation and
	testbed scenarios used in research on Internet congestion control		testbed scenarios used in research on Internet congestion control
	mechanisms. We believe that research in congestion control		mechanisms. We believe that research in congestion control
	mechanisms has been seriously hampered by the lack of good models		mechanisms has been seriously hampered by the lack of good models
	underpinning analysis, simulation, and testbed experiments, and that		underpinning analysis, simulation, and testbed experiments, and that
	tools for the evaluation of simulation and testbed scenarios can		tools for the evaluation of simulation and testbed scenarios can
	help in the construction of better scenarios, based on better		help in the construction of better scenarios, based on better
	skipping to change at page 3, line 14 ¶		skipping to change at page 3, line 14 ¶
	Table of Contents		Table of Contents
	1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . 5		1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . 5
	2. Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6		2. Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
	2.1. Characterizing Aggregate Traffic on a Link . . . . . . . 6		2.1. Characterizing Aggregate Traffic on a Link . . . . . . . 6
	2.2. Characterizing an End-to-End Path. . . . . . . . . . . . 6		2.2. Characterizing an End-to-End Path. . . . . . . . . . . . 6
	2.3. Other Characteristics. . . . . . . . . . . . . . . . . . 7		2.3. Other Characteristics. . . . . . . . . . . . . . . . . . 7
	3. The Distribution of Per-packet Round-trip Times . . . . . . . 7		3. The Distribution of Per-packet Round-trip Times . . . . . . . 7
	4. The Distribution of Connection Sizes. . . . . . . . . . . . . 8		4. The Distribution of Connection Sizes. . . . . . . . . . . . . 8
	5. The Distribution of Packet Sizes. . . . . . . . . . . . . . . 9		5. The Distribution of Packet Sizes. . . . . . . . . . . . . . . 10
	6. The Ratio Between Forward-path and Reverse-path Traf-		6. The Ratio Between Forward-path and Reverse-path Traf-
	fic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10		fic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
	7. The Distribution of Per-Packet Peak Flow Rates. . . . . . . . 11		7. The Distribution of Per-Packet Peak Flow Rates. . . . . . . . 11
	8. The Distribution of Transport Protocols.. . . . . . . . . . . 11		8. The Distribution of Transport Protocols.. . . . . . . . . . . 12
	9. The Synchronization Ratio . . . . . . . . . . . . . . . . . . 12		9. The Synchronization Ratio . . . . . . . . . . . . . . . . . . 12
	10. Drop or Mark Rates as a Function of Packet Size. . . . . . . 13		10. Drop or Mark Rates as a Function of Packet Size. . . . . . . 14
	11. Drop Rates as a Function of Burst Size.. . . . . . . . . . . 15		11. Drop Rates as a Function of Burst Size.. . . . . . . . . . . 16
	12. Drop Rates as a Function of Sending Rate.. . . . . . . . . . 18		12. Drop Rates as a Function of Sending Rate.. . . . . . . . . . 18
	13. Congestion Control Mechanisms for Traffic, along		13. Congestion Control Mechanisms for Traffic, along
	with Sender and Receiver Buffer Sizes. . . . . . . . . . . . . . 18		with Sender and Receiver Buffer Sizes. . . . . . . . . . . . . . 19
	14. Characterization of Congested Links in Terms of		14. Characterization of Congested Links in Terms of
	Bandwidth and Typical Levels of Congestion . . . . . . . . . . . 18		Bandwidth and Typical Levels of Congestion . . . . . . . . . . . 19
	14.1. Bandwidth . . . . . . . . . . . . . . . . . . . . . . . 19		14.1. Bandwidth . . . . . . . . . . . . . . . . . . . . . . . 19
	14.2. Queue Management Mechanisms . . . . . . . . . . . . . . 19		14.2. Queue Management Mechanisms . . . . . . . . . . . . . . 19
	14.3. Typical Levels of Congestion. . . . . . . . . . . . . . 19		14.3. Typical Levels of Congestion. . . . . . . . . . . . . . 19
	15. Characterization of Challenging Lower Layers.. . . . . . . . 19		15. Characterization of Challenging Lower Layers.. . . . . . . . 19
	15.1. Error Losses. . . . . . . . . . . . . . . . . . . . . . 19		15.1. Error Losses. . . . . . . . . . . . . . . . . . . . . . 20
	15.2. Packet Reordering . . . . . . . . . . . . . . . . . . . 20		15.2. Packet Reordering . . . . . . . . . . . . . . . . . . . 20
	15.3. Delay Variation . . . . . . . . . . . . . . . . . . . . 20		15.3. Delay Variation . . . . . . . . . . . . . . . . . . . . 21
	15.4. Bandwidth Variation . . . . . . . . . . . . . . . . . . 21		15.4. Bandwidth Variation . . . . . . . . . . . . . . . . . . 22
	15.5. Bandwidth and Latency Asymmetry . . . . . . . . . . . . 22		15.5. Bandwidth and Latency Asymmetry . . . . . . . . . . . . 23
	15.6. Queue Management Mechanisms . . . . . . . . . . . . . . 23		15.6. Queue Management Mechanisms . . . . . . . . . . . . . . 24
	16. Network Changes Affecting Congestion . . . . . . . . . . . . 23		16. Network Changes Affecting Congestion . . . . . . . . . . . . 24
	16.1. Routing Changes: Routing Loops . . . . . . . . . . . . 24		16.1. Routing Changes: Routing Loops . . . . . . . . . . . . 24
	16.2. Routing Changes: Fluttering. . . . . . . . . . . . . . 24		16.2. Routing Changes: Fluttering. . . . . . . . . . . . . . 25
	16.3. Routing Changes: Routing Asymmetry . . . . . . . . . . 25		16.3. Routing Changes: Routing Asymmetry . . . . . . . . . . 26
	16.4. Link Disconnections and Intermittent Link Con-		16.4. Link Disconnections and Intermittent Link Con-
	nectivity . . . . . . . . . . . . . . . . . . . . . . . . . . 25		nectivity . . . . . . . . . . . . . . . . . . . . . . . . . . 26
	16.5. Changes in Wireless Links: Mobility . . . . . . . . . . 26		16.5. Changes in Wireless Links: Mobility . . . . . . . . . . 27
	17. Using the Tools Presented in this Document . . . . . . . . . 27		17. Using the Tools Presented in this Document . . . . . . . . . 27
	18. Related Work . . . . . . . . . . . . . . . . . . . . . . . . 27		18. Related Work . . . . . . . . . . . . . . . . . . . . . . . . 27
	19. Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . 27		19. Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . 27
	20. Security Considerations. . . . . . . . . . . . . . . . . . . 27		20. Security Considerations. . . . . . . . . . . . . . . . . . . 27
	21. IANA Considerations. . . . . . . . . . . . . . . . . . . . . 27		21. IANA Considerations. . . . . . . . . . . . . . . . . . . . . 28
	22. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 27		22. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 28
	Informative References . . . . . . . . . . . . . . . . . . . . . 27		Informative References . . . . . . . . . . . . . . . . . . . . . 28
	Editors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32
	Full Copyright Statement . . . . . . . . . . . . . . . . . . . . 31		Full Copyright Statement . . . . . . . . . . . . . . . . . . . . 32
	Intellectual Property. . . . . . . . . . . . . . . . . . . . . . 32		Intellectual Property. . . . . . . . . . . . . . . . . . . . . . 32
	TO BE DELETED BY THE RFC EDITOR UPON PUBLICATION:		TO BE DELETED BY THE RFC EDITOR UPON PUBLICATION:
			Changes from draft-irtf-tmrg-tools-04.txt:
			* Added to the cection on "Congestion Control Mechanisms for
			Traffic". From a contribution from Sara Landstrom.
	Changes from draft-irtf-tmrg-tools-03.txt:		Changes from draft-irtf-tmrg-tools-03.txt:
	* No changes.		* No changes.
	Changes from draft-irtf-tmrg-tools-02.txt:		Changes from draft-irtf-tmrg-tools-02.txt:
	* Added sections on Challenging Lower Layers and Network		* Added sections on Challenging Lower Layers and Network
	Changes affecting Congestion. Contributed by Jasani Rohan,		Changes affecting Congestion. Contributed by Jasani Rohan,
	with Julie Tarr, Tony Desimone, Christou Christos, and		with Julie Tarr, Tony Desimone, Christou Christos, and
	Vemulapalli Archana.		Vemulapalli Archana.
	* Minor editing.		* Minor editing.
	Changes from draft-irtf-tmrg-tools-01.txt:		Changes from draft-irtf-tmrg-tools-01.txt:
	* Added section on "Drop Rates as a Function of Sending Rate."		* Added section on "Drop Rates as a Function of Sending Rate."
	* Added a number of new references.		* Added a number of new references.
	END OF SECTION TO BE DELETED.		END OF SECTION TO BE DELETED.
	1. Introduction		1. Introduction
	This document discusses tools for the evaluation of simulation and		This document discusses tools for the evaluation of simulation and
	testbed scenarios used in research on Internet congestion control		testbed scenarios used in research on Internet congestion control
	skipping to change at page 18, line 42 ¶		skipping to change at page 19, line 10 ¶
	Internet, the level of statistical multiplexing on the congested		Internet, the level of statistical multiplexing on the congested
	links of an end-to-end path can be inferred indirectly through per-		links of an end-to-end path can be inferred indirectly through per-
	flow measurements, by observing whether the packet drop rate varies		flow measurements, by observing whether the packet drop rate varies
	as a function of the sending rate of the flow.		as a function of the sending rate of the flow.
	13. Congestion Control Mechanisms for Traffic, along with Sender and		13. Congestion Control Mechanisms for Traffic, along with Sender and
	Receiver Buffer Sizes.		Receiver Buffer Sizes.
	Effect on congestion control metrics: Please don't evaluate AQM		Effect on congestion control metrics: Please don't evaluate AQM
	mechanisms by using Reno TCP, or evaluate new transport protocols by		mechanisms by using Reno TCP, or evaluate new transport protocols by
	comparing them with the performance of Reno TCP! For an		comparing them with the performance of Reno TCP. For measurement
	explanation, see [FK02] (Section 3.4).		data, see below. For a more detailed explanation, see [FK02]
			(Section 3.4).
	Measurements: See [MAF05].		SACK and DSACK: Medina et al. in [MAF05] tested 84,394 servers for
			SACK capability. Of these, the majority, 68%, were SACK-Capable.
			Approximately half of the SACK-Capable web servers supported DSACK.
			Allman in [A00] reports that the percentage of web clients that were
			SACK-Capable increased from 8% in December 1998 to 40% in March
			2000. This trend continued, with 88% of the clients advertising
			`SACK permitted' in the 2004 data reported in [MAF05]. Only 3% of
			the clients sent DSACKs, but this number does not reveal how many
			clients would have sent DSACKs upon receiving duplicate data.
			Reno and NewReno: When the TBIT client used by Medina et al. in
			[MAF05] pretended not to be SACK-Capable, only 33% of the web
			servers were classified as NewReno, Reno, Tahoe, or Other, but of
			these, the majority (76%) were classified as NewReno, and 15% were
			classified as Reno. In [PF01] NewReno was already observed as the
			dominating congestion control algorithm in the absence of SACK
			information. Out of 3,728 web servers, 1,571 performed NewReno
			congestion control in that investigation.
	14. Characterization of Congested Links in Terms of Bandwidth and		14. Characterization of Congested Links in Terms of Bandwidth and
	Typical Levels of Congestion		Typical Levels of Congestion
	14.1. Bandwidth		14.1. Bandwidth
	14.2. Queue Management Mechanisms		14.2. Queue Management Mechanisms
	14.3. Typical Levels of Congestion		14.3. Typical Levels of Congestion
	[Pointers to the current state of our knowledge.]		[Pointers to the current state of our knowledge.]
	15. Characterization of Challenging Lower Layers.		15. Characterization of Challenging Lower Layers.
	skipping to change at page 27, line 31 ¶		skipping to change at page 28, line 15 ¶
	21. IANA Considerations		21. IANA Considerations
	There are no IANA considerations in this document.		There are no IANA considerations in this document.
	22. Acknowledgements		22. Acknowledgements
	Thanks to Xiaoliang (David) Wei for feedback and contributions to		Thanks to Xiaoliang (David) Wei for feedback and contributions to
	this document. The sections on "Challenging Lower Layers" and		this document. The sections on "Challenging Lower Layers" and
	"Network Changes Affecting Congestion" are contributions from Jasani		"Network Changes Affecting Congestion" are contributions from Jasani
	Rohan with Julie Tarr, Tony Desimone, Christou Christos, and		Rohan with Julie Tarr, Tony Desimone, Christou Christos, and
	Vemulapalli Archana.		Vemulapalli Archana. The section on "Congestion Control Mechanisms
			for Traffic, along with Sender and Receiver Buffer Sizes" includes
			contributions from Sara Landstrom.
	Informative References		Informative References
	[MAWI] M.W. Group, Mawi working group traffic archive, URL		[MAWI] M.W. Group, Mawi working group traffic archive, URL
	"http://tracer.csl.sony.jp/mawi/".		"http://tracer.csl.sony.jp/mawi/".
	[A00] M. Allman, A Web Server's View of the Transport Layer,		[A00] M. Allman, A Web Server's View of the Transport Layer,
	Computer Communication Review, 30(5), October 200.		Computer Communication Review, 30(5), October 200.
	[AAR03] Alhussein A. Abouzeid, Sumit Roy, Stochastic Modeling of TCP		[AAR03] Alhussein A. Abouzeid, Sumit Roy, Stochastic Modeling of TCP
	skipping to change at page 30, line 14 ¶		skipping to change at page 30, line 47 ¶
	[MAF05] A. Medina, M. Allman, and A. Floyd. Measuring the Evolution		[MAF05] A. Medina, M. Allman, and A. Floyd. Measuring the Evolution
	of Transport Protocols in the Internet. Computer Communication		of Transport Protocols in the Internet. Computer Communication
	Review, April 2005.		Review, April 2005.
	[NISTNet] NIST Net, URL "http://snad.ncsl.nist.gov/itg/nistnet/".		[NISTNet] NIST Net, URL "http://snad.ncsl.nist.gov/itg/nistnet/".
	[NM01] J. Neale and A. Mohsen. Impact of CF-DAMA on TCP via		[NM01] J. Neale and A. Mohsen. Impact of CF-DAMA on TCP via
	Satellite Performance. Globecom, Nov. 2001.		Satellite Performance. Globecom, Nov. 2001.
			[PF01] J. Padhye and S. Floyd, Identifying the TCP Behavior of Web
			Servers, SIGCOMM 2001, August 2001.
	[P96] Paxson, V., (1996) End-to-end Routing Behavior in the		[P96] Paxson, V., (1996) End-to-end Routing Behavior in the
	Internet. Proceedings of SIGCOMM 96, pp. 25-38, August 1992.		Internet. Proceedings of SIGCOMM 96, pp. 25-38, August 1992.
	[P97] V. Paxson. End-to-end Routing Behavior in the Internet.		[P97] V. Paxson. End-to-end Routing Behavior in the Internet.
	IEEE/ACM Transactions on Networking, 5(5):60115, October 1997.		IEEE/ACM Transactions on Networking, 5(5):60115, October 1997.
	[PJD04] R. Prasad, M. Jain, and C. Dovrolis, On the Effectiveness of		[PJD04] R. Prasad, M. Jain, and C. Dovrolis, On the Effectiveness of
	Delay-Based Congestion Avoidance, PFLDnet 2004, February 2004.		Delay-Based Congestion Avoidance, PFLDnet 2004, February 2004.
	[QZK01] L. Qiu, Y. Zhang, and S. Keshav, Understanding the		[QZK01] L. Qiu, Y. Zhang, and S. Keshav, Understanding the
	skipping to change at page 31, line 22 ¶		skipping to change at page 32, line 11 ¶
	[ZSC91] L. Zhang, S. Shenker, and D.D. Clark, Observations and		[ZSC91] L. Zhang, S. Shenker, and D.D. Clark, Observations and
	Dynamics of a Congestion Control Algorithm: the Effects of Two-		Dynamics of a Congestion Control Algorithm: the Effects of Two-
	way Traffic, SIGCOMM 1991.		way Traffic, SIGCOMM 1991.
	[22]		[22]
	[23]		[23]
	[24]		[24]
	Editors' Addresses		Authors' Addresses
	Sally Floyd <floyd@icir.org>		Sally Floyd
	ICSI Center for Internet Research		ICSI Center for Internet Research
	1947 Center Street, Suite 600		1947 Center Street, Suite 600
	Berkeley, CA 94704		Berkeley, CA 94704
	USA		USA
			Email: floyd@acm.org
	Eddie Kohler <kohler@cs.ucla.edu>		Eddie Kohler
	4531C Boelter Hall		4531C Boelter Hall
	UCLA Computer Science Department		UCLA Computer Science Department
	Los Angeles, CA 90095		Los Angeles, CA 90095
	USA		USA
			Email: kohler@cs.ucla.edu
	Full Copyright Statement		Full Copyright Statement
	Copyright (C) The IETF Trust (2007). This document is subject to		Copyright (C) The IETF Trust (2008). This document is subject to
	the rights, licenses and restrictions contained in BCP 78, and		the rights, licenses and restrictions contained in BCP 78, and
	except as set forth therein, the authors retain all their rights.		except as set forth therein, the authors retain all their rights.
	This document and the information contained herein are provided on		This document and the information contained herein are provided on
	an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE		an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
	REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE		REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE
	IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL		IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL
	WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY		WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY
	WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE		WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE
	ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS		ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
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