draft-ietf-ippm-active-passive-03.txt		draft-ietf-ippm-active-passive-04.txt
	Network Working Group A. Morton		Network Working Group A. Morton
	Internet-Draft AT&T Labs		Internet-Draft AT&T Labs
	Intended status: Informational November 2, 2015		Intended status: Informational December 10, 2015
	Expires: May 5, 2016		Expires: June 12, 2016
	Active and Passive Metrics and Methods (and everything in-between, or		Active and Passive Metrics and Methods (and everything in-between, or
	Hybrid)		Hybrid)
	draft-ietf-ippm-active-passive-03		draft-ietf-ippm-active-passive-04
	Abstract		Abstract
	This memo provides clear definitions for Active and Passive		This memo provides clear definitions for Active and Passive
	performance assessment. The construction of Metrics and Methods can		performance assessment. The construction of Metrics and Methods can
	be described as Active or Passive. Some methods may use a subset of		be described as Active or Passive. Some methods may use a subset of
	both active and passive attributes, and we refer to these as Hybrid		both active and passive attributes, and we refer to these as Hybrid
	Methods.		Methods. This memo also describes multiple dimensions to help
			evaluate new methods as they emerge.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	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 May 5, 2016.		This Internet-Draft will expire on June 12, 2016.
	Copyright Notice		Copyright Notice
	Copyright (c) 2015 IETF Trust and the persons identified as the		Copyright (c) 2015 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 3, line 10		skipping to change at page 3, line 10
	packet stream and observations of the stream.		packet stream and observations of the stream.
	A Passive metric or method depends *solely* on observation of one		A Passive metric or method depends *solely* on observation of one
	or more existing packet streams. The streams only serve		or more existing packet streams. The streams only serve
	measurement when they are observed for that purpose, and are		measurement when they are observed for that purpose, and are
	present whether measurements take place or not.		present whether measurements take place or not.
	As new techniques for assessment emerge it is helpful to have clear		As new techniques for assessment emerge it is helpful to have clear
	definitions of these notions. This memo provides more detailed		definitions of these notions. This memo provides more detailed
	definitions, defines a new category for combinations of traditional		definitions, defines a new category for combinations of traditional
	active and passive techniques, and discusses means to evaluate new		active and passive techniques, and discusses dimensions to evaluate
	techniques as they emerge.		new techniques as they emerge.
	This memo provides definitions for Active and Passive Metrics and		This memo provides definitions for Active and Passive Metrics and
	Methods based on long usage in the Internet measurement community,		Methods based on long usage in the Internet measurement community,
	and especially the Internet Engineering Task Force. This memo also		and especially the Internet Engineering Task Force. This memo also
	describes the comnination of fundamental Active and Passive		describes the combination of fundamental Active and Passive
	categories, which are called Hybrid Methods and Metrics.		categories, which are called Hybrid Methods and Metrics.
	1.1. Requirements Language		1.1. Requirements Language
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in RFC 2119 [RFC2119].		document are to be interpreted as described in RFC 2119 [RFC2119].
	2. Purpose and Scope		2. Purpose and Scope
	The scope of this memo is to define and describe Active and Passive		The scope of this memo is to define and describe Active and Passive
	versions of metrics and methods which are consistent with the long-		versions of metrics and methods which are consistent with the long-
	time usage of these adjectives in the Internet measurement community		time usage of these adjectives in the Internet measurement community
	and especially the Internet Engineering Task Force. Since the		and especially the Internet Engineering Task Force. Since the
	science of measurement is expanding, we provide a category for		science of measurement is expanding, we provide a category for
	combinations of the traditional extremes, treating Active and Passive		combinations of the traditional extremes, treating Active and Passive
	as a continuum and designating combinations of their attributes as		as a continuum and designating combinations of their attributes as
	Hybrid methods.		Hybrid methods.
	Further, this memo's purpose includes describing multiple dimensions		Further, this memo's purpose includes describing multiple dimensions
	in which to evaluate methods as they emerge.		to evaluate new methods as they emerge.
	3. Terms and Definitions		3. Terms and Definitions
	This section defines the key terms of the memo. Some definitions use		This section defines the key terms of the memo. Some definitions use
	the notion of "stream of interest" which is synonymous with		the notion of "stream of interest" which is synonymous with
	"population of interest" defined in clause 6.1.1 of ITU-T		"population of interest" defined in clause 6.1.1 of ITU-T
	Recommendation Y.1540 [Y.1540]. The definitions are consistent with		Recommendation Y.1540 [Y.1540]. The definitions are consistent with
	[I-D.zheng-ippm-framework-passive].		[I-D.zheng-ippm-framework-passive].
	3.1. Performance Metric		3.1. Performance Metric
	skipping to change at page 4, line 17		skipping to change at page 4, line 17
	3.2. Method of Measurement		3.2. Method of Measurement
	The procedure or set of operations having the object of determining a		The procedure or set of operations having the object of determining a
	Measured Value or Measurement Result.		Measured Value or Measurement Result.
	3.3. Observation Point		3.3. Observation Point
	See section 2 of [RFC7011] for this definition (a location in the		See section 2 of [RFC7011] for this definition (a location in the
	network where packets can be observed), and related definitions. The		network where packets can be observed), and related definitions. The
	comparable term defined in IETF literature on Active measurement is		comparable term defined in IETF literature on Active measurement is
	Measurement Point, see section 4.1 of [RFC5835]. Two terms have come		Measurement Point, see section 4.1 of [RFC5835]. Both of these terms
	into use describing similar actions at the identified point in the		have come into use describing similar actions at the identified point
	network path.		in the network path.
	3.4. Active Methods		3.4. Active Methods
	Active measurement methods have the following attributes:		Active measurement methods have the following attributes:
	1. Commonly, the packet stream of interest is generated as the basis		1. Active methods generate packet streams. Commonly, the packet
	of measurement. Sometimes, the adjective "synthetic" is used to		stream of interest is generated as the basis of measurement.
	categorize Active measurement streams [Y.1731]. Accompanying		Sometimes, the adjective "synthetic" is used to categorize Active
	packet stream(s) may be generated to increase overall traffic		measurement streams [Y.1731]. Accompanying packet stream(s) may
	load, though the loading stream(s) may not be measured.		be generated to increase overall traffic load, though the loading
			stream(s) may not be measured.
	2. The packets in the stream of interest have fields or field values		2. The packets in the stream of interest have fields or field values
	(or are augmented or modified to include fields or field values)		(or are augmented or modified to include fields or field values)
	which are dedicated to measurement. Since measurement usually		which are dedicated to measurement. Since measurement usually
	requires determining the corresponding packets at multiple		requires determining the corresponding packets at multiple
	measurement points, a sequence number is the most common		measurement points, a sequence number is the most common
	information dedicated to measurement, and often combined with a		information dedicated to measurement, and often combined with a
	timestamp.		timestamp.
	3. The Source and Destination of the packet stream of interest are		3. The Source and Destination of the packet stream of interest are
	usually known a priori.		usually known a priori.
	4. The characteristics of the packet stream of interest are known at		4. The characteristics of the packet stream of interest are known at
	the Source at least, and may be communicated to Destination as		the Source at least, and may be communicated to Destination as
	part of the method. Note that some packet characteristics will		part of the method. Note that some packet characteristics will
	normaly change during packet forwarding. Other changes along the		normally change during packet forwarding. Other changes along
	path are possible, see [I-D.morton-ippm-2330-stdform-typep].		the path are possible, see [I-D.morton-ippm-2330-stdform-typep].
	When adding traffic to the network for measurement, Active Methods		When adding traffic to the network for measurement, Active Methods
	influence the quantities measured to some degree, and those		influence the quantities measured to some degree, and those
	performing tests should take steps to quantify the effect(s) and/or		performing tests should take steps to quantify the effect(s) and/or
	minimize such effects.		minimize such effects.
	3.5. Active Metric		3.5. Active Metric
	An Active Metric incorporates one or more of the aspects of Active		An Active Metric incorporates one or more of the aspects of Active
	Methods in the metric definition.		Methods in the metric definition.
	skipping to change at page 5, line 23		skipping to change at page 5, line 25
	packet characteristics (Type-P) and Source and Destination IP		packet characteristics (Type-P) and Source and Destination IP
	addresses (with their implications on both stream treatment and		addresses (with their implications on both stream treatment and
	interfaces associated with measurement points).		interfaces associated with measurement points).
	3.6. Passive Methods		3.6. Passive Methods
	Passive measurement methods are		Passive measurement methods are
	o based solely on observations of undisturbed and unmodified packet		o based solely on observations of undisturbed and unmodified packet
	stream of interest (in other words, the method of measurement MUST		stream of interest (in other words, the method of measurement MUST
	NOT add, change, or remove fields, or change field values anywhere		NOT add, change, or remove packets or fields, or change field
	along the path).		values anywhere along the path).
	o dependent on the existence of one or more packet streams to supply		o dependent on the existence of one or more packet streams to supply
	the stream of interest		the stream of interest.
	o dependent on the presence of the packet stream of interest at one		o dependent on the presence of the packet stream of interest at one
	or more designated observation points.		or more designated observation points.
	Some passive methods simply observe and collect information on all		Some passive methods simply observe and collect information on all
	packets that pass Observation Point(s), while others filter the		packets that pass Observation Point(s), while others filter the
	packets as a first step and only collect information on packets that		packets as a first step and only collect information on packets that
	match the filter criteria, and thereby narrow the stream of interest.		match the filter criteria, and thereby narrow the stream of interest.
	It is common that passive methods are conducted at one or more		It is common that passive methods are conducted at one or more
	skipping to change at page 7, line 39		skipping to change at page 7, line 41
	| of Interest | Streams of Interest		| of Interest | Streams of Interest
	| | from Different Methods		| | from Different Methods
	====================================================================		====================================================================
	Single Fundamental | Active or Passive |		Single Fundamental | Active or Passive |
	Method | |		Method | |
	Synthesis of | Hybrid Type I |		Synthesis of | Hybrid Type I |
	Fundamental Methods | |		Fundamental Methods | |
	Multiple Methods | Spatial Metrics | Hybrid Type II		Multiple Methods | Spatial Metrics | Hybrid Type II
	| [RFC 5644] |		| [RFC5644] |
	There may be circumstances where results measured with Hybrid Methods		There may be circumstances where results measured with Hybrid Methods
	can be considered equivalent to Passive Methods. Referencing the		can be considered equivalent to Passive Methods. Referencing the
	notion of a "class C" where packets of different Type-P are treated		notion of a "class C" where packets of different Type-P are treated
	equally in Section 13 of [RFC2330]and the terminology for paths from		equally in Section 13 of [RFC2330]and the terminology for paths from
	Section 5 of [RFC2330]:		Section 5 of [RFC2330]:
	Hybrid Methods of Measurement that augment or modify packets of a		Hybrid Methods of Measurement that augment or modify packets of a
	"class C" in a host should produce equivalent results to Passive		"class C" in a host should produce equivalent results to Passive
	Methods of Measurement, when hosts accessing and links transporting		Methods of Measurement, when hosts accessing and links transporting
	skipping to change at page 8, line 36		skipping to change at page 8, line 39
	a key dimension for Active measurement error analysis. (Comment:		a key dimension for Active measurement error analysis. (Comment:
	There is also the notion of time averages - a measurement stream		There is also the notion of time averages - a measurement stream
	may have significant effect while it is present, but the stream is		may have significant effect while it is present, but the stream is
	only generated 0.1% of the time. On the other hand, observations		only generated 0.1% of the time. On the other hand, observations
	alone have no effect on network performance. To keep these		alone have no effect on network performance. To keep these
	dimensions simple, we consider the stream effect only when it is		dimensions simple, we consider the stream effect only when it is
	present, but note that reactive networks defined in [RFC7312] may		present, but note that reactive networks defined in [RFC7312] may
	exhibit bias for some time beyond the life of a stream.)		exhibit bias for some time beyond the life of a stream.)
	X-Axis: "a priori Stream Knowledge." The degree to which stream		X-Axis: "a priori Stream Knowledge." The degree to which stream
	characteristics are know a priori. There are methodological		characteristics are known a priori. There are methodological
	advantages of knowing the source stream characteristics, and		advantages of knowing the source stream characteristics, and
	having complete control of the stream characteristics. For		having complete control of the stream characteristics. For
	example, knowing the number of packets in a stream allows more		example, knowing the number of packets in a stream allows more
	efficient operation of the measurement receiver, and so is an		efficient operation of the measurement receiver, and so is an
	asset for active measurement methods. Passive methods (with no		asset for active measurement methods. Passive methods (with no
	sample filter) have few clues available to anticipate what the		sample filter) have few clues available to anticipate what the
	protocol first packet observed will use or how many packets will		protocol first packet observed will use or how many packets will
	comprise the flow, but once the standard protocol of a flow is		comprise the flow, but once the standard protocol of a flow is
	known the possibilities narrow (for some compliant flows).		known the possibilities narrow (for some compliant flows).
	Therefore this is a key dimension for Passive measurement error		Therefore this is a key dimension for Passive measurement error
	skipping to change at page 9, line 41		skipping to change at page 9, line 44
	1. effect on the performance of the stream of interest itself: for		1. effect on the performance of the stream of interest itself: for
	example, choosing a packet marking or DSCP resulting in domain		example, choosing a packet marking or DSCP resulting in domain
	treatment as a real-time stream (as opposed to default/best-		treatment as a real-time stream (as opposed to default/best-
	effort marking.		effort marking.
	2. effect on unmeasured streams that share the path and/or		2. effect on unmeasured streams that share the path and/or
	bottlenecks: for example, an extremely sparse measured stream of		bottlenecks: for example, an extremely sparse measured stream of
	minimal size packets typically has little effect on other flows		minimal size packets typically has little effect on other flows
	(and itself), while a stream designed to characterize path		(and itself), while a stream designed to characterize path
	capacity may effect all other flows passing through the capacity		capacity may affect all other flows passing through the capacity
	bottleneck (including itself).		bottleneck (including itself).
	3. effect on network conditions resulting in network adaptation: for		3. effect on network conditions resulting in network adaptation: for
	example, a network monitoring load and congestion conditions		example, a network monitoring load and congestion conditions
	might change routing, placing some flows to alternate paths to		might change routing, placing some flows to alternate paths to
	mitigate the congestion.		mitigate the congestion.
	We have combined 1 and 2 on the Y-axis, as examination of examples		We have combined 1 and 2 on the Y-axis, as examination of examples
	indicates strong correlation of affects in this pair, and network		indicates strong correlation of effects in this pair, and network
	adaptation is not addressed.		adaptation is not addressed.
	It is apparent that different methods of IP network measurement can		It is apparent that different methods of IP network measurement can
	produce different results, even when measuring the same path at the		produce different results, even when measuring the same path at the
	same time. The two dimensions of the graph help to understand how		same time. The two dimensions of the graph help to understand how
	the results might change with the method chosen. For example, an		the results might change with the method chosen. For example, an
	Active Method to assess throughput adds some amount of traffic to the		Active Method to assess throughput adds some amount of traffic to the
	network which might result in lower throughput for all streams.		network which might result in lower throughput for all streams.
	However, a Passive Method to assess throughput can also err on the		However, a Passive Method to assess throughput can also err on the
	low side due to unknown limitations of the hosts providing traffic,		low side due to unknown limitations of the hosts providing traffic,
	skipping to change at page 11, line 50		skipping to change at page 12, line 5
	A. This method processes a user traffic stream,		A. This method processes a user traffic stream,
	B. and augments the stream of interest with frames having "fields		B. and augments the stream of interest with frames having "fields
	which are dedicated to measurement".		which are dedicated to measurement".
	o Synthetic Loss Measurement (SLM) and Delay Measurement (DM)		o Synthetic Loss Measurement (SLM) and Delay Measurement (DM)
	methods both inject dedicated measurement frames, so the "stream		methods both inject dedicated measurement frames, so the "stream
	of interest is generated as the basis of measurement". We		of interest is generated as the basis of measurement". We
	conclude that SLM and DM methods are Active Methods.		conclude that SLM and DM methods are Active Methods.
	We also recognize the existance of alternate terminology used in OAM		We also recognize the existence of alternate terminology used in OAM
	at layers other than IP. Readers are encouraged to consult [RFC6374]		at layers other than IP. Readers are encouraged to consult [RFC6374]
	for MPLS Loss and Delay measurement terminology, for example.		for MPLS Loss and Delay measurement terminology, for example.
	5. Security considerations		5. Security considerations
	When considering privacy of those involved in measurement or those		When considering privacy of those involved in measurement or those
	whose traffic is measured, there is sensitive information		whose traffic is measured, there is sensitive information
	communicated and observed at observation and measurement points		communicated and observed at observation and measurement points
	described above. We refer the reader to the privacy considerations		described above. We refer the reader to the privacy considerations
	described in the Large Scale Measurement of Broadband Performance		described in the Large Scale Measurement of Broadband Performance
	skipping to change at page 12, line 26		skipping to change at page 12, line 30
	6. IANA Considerations		6. IANA Considerations
	This memo makes no requests for IANA consideration.		This memo makes no requests for IANA consideration.
	7. Acknowledgements		7. Acknowledgements
	Thanks to Mike Ackermann for asking the right question, and for		Thanks to Mike Ackermann for asking the right question, and for
	several suggestions on terminology. Brian Trammell provided key		several suggestions on terminology. Brian Trammell provided key
	terms and references for the passive category, and suggested ways to		terms and references for the passive category, and suggested ways to
	expand the Hybrid description and types. Phil Eardley suggested some		expand the Hybrid description and types. Phil Eardley suggested some
	hybrid scenaios for categorization as part of his review. Tiziano		hybrid scenarios for categorization as part of his review. Tiziano
	Ionta reviewed the draft and suggested the classification for the		Ionta reviewed the draft and suggested the classification for the
	"coloring" method of measurement. Nalini Elkins identified several		"coloring" method of measurement. Nalini Elkins identified several
	areas for clarification following her review. Bill Jouris suggested		areas for clarification following her review. Bill Jouris, Stenio
	several editorial improvements. Tal Mizrahi, Joachim Fabini, Greg		Fernandes, and Spencer Dawkins suggested several editorial
	Mirsky and Mike Ackermann raised many key considerations in their		improvements. Tal Mizrahi, Joachim Fabini, Greg Mirsky and Mike
	WGLC reviews, based on their broad measurement experience.		Ackermann raised many key considerations in their WGLC reviews, based
			on their broad measurement experience.
	8. References		8. References
	8.1. Normative References		8.1. Normative References
	[RFC2330] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,		[RFC2330] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,
	"Framework for IP Performance Metrics", RFC 2330,		"Framework for IP Performance Metrics", RFC 2330,
	DOI 10.17487/RFC2330, May 1998,		DOI 10.17487/RFC2330, May 1998,
	<http://www.rfc-editor.org/info/rfc2330>.		<http://www.rfc-editor.org/info/rfc2330>.
End of changes. 19 change blocks.
	32 lines changed or deleted		35 lines changed or added
This html diff was produced by rfcdiff 1.42. The latest version is available from http://tools.ietf.org/tools/rfcdiff/