draft-ietf-ippm-2680-bis-05.txt		rfc7680.txt
	Network Working Group G. Almes		Internet Engineering Task Force (IETF) G. Almes
	Internet-Draft Texas A&M		Request for Comments: 7680 Texas A&M
	Obsoletes: 2680 (if approved) S. Kalidindi		STD: 82 S. Kalidindi
	Intended status: Standards Track Ixia		Obsoletes: 2680 Ixia
	Expires: February 21, 2016 M. Zekauskas		Category: Standards Track M. Zekauskas
	Internet2		ISSN: 2070-1721 Internet2
	A. Morton, Ed.		A. Morton, Ed.
	AT&T Labs		AT&T Labs
	August 20, 2015		January 2016
	A One-Way Loss Metric for IPPM		A One-Way Loss Metric for IP Performance Metrics (IPPM)
	draft-ietf-ippm-2680-bis-05
	Abstract		Abstract
	This memo (RFC 2680 bis) defines a metric for one-way loss of packets		This memo defines a metric for one-way loss of packets across
	across Internet paths. It builds on notions introduced and discussed		Internet paths. It builds on notions introduced and discussed in the
	in the IPPM Framework document, RFC 2330; the reader is assumed to be		IP Performance Metrics (IPPM) Framework document, RFC 2330; the
	familiar with that document. This memo makes RFC 2680 obsolete.		reader is assumed to be familiar with that document. This memo makes
			RFC 2680 obsolete.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This is an Internet Standards Track document.
	provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		This document is a product of the Internet Engineering Task Force
	and may be updated, replaced, or obsoleted by other documents at any		(IETF). It represents the consensus of the IETF community. It has
	time. It is inappropriate to use Internet-Drafts as reference		received public review and has been approved for publication by the
	material or to cite them other than as "work in progress."		Internet Engineering Steering Group (IESG). Further information on
			Internet Standards is available in Section 2 of RFC 5741.
	This Internet-Draft will expire on February 21, 2016.		Information about the current status of this document, any errata,
			and how to provide feedback on it may be obtained at
			http://www.rfc-editor.org/info/rfc7680.
	Copyright Notice		Copyright Notice
	Copyright (c) 2015 IETF Trust and the persons identified as the		Copyright (c) 2016 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
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	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
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	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
	1.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . 3		1.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . 5
	1.2. General Issues Regarding Time . . . . . . . . . . . . . . 4		1.2. General Issues regarding Time . . . . . . . . . . . . . . 6
	2. A Singleton Definition for One-way Packet Loss . . . . . . . 6		2. A Singleton Definition for One-Way Packet Loss . . . . . . . 7
	2.1. Metric Name: . . . . . . . . . . . . . . . . . . . . . . 6		2.1. Metric Name . . . . . . . . . . . . . . . . . . . . . . . 7
	2.2. Metric Parameters: . . . . . . . . . . . . . . . . . . . 6		2.2. Metric Parameters . . . . . . . . . . . . . . . . . . . . 7
	2.3. Metric Units: . . . . . . . . . . . . . . . . . . . . . . 6		2.3. Metric Units . . . . . . . . . . . . . . . . . . . . . . 7
	2.4. Definition: . . . . . . . . . . . . . . . . . . . . . . . 6		2.4. Definition . . . . . . . . . . . . . . . . . . . . . . . 7
	2.5. Discussion: . . . . . . . . . . . . . . . . . . . . . . . 6		2.5. Discussion . . . . . . . . . . . . . . . . . . . . . . . 8
	2.6. Methodologies: . . . . . . . . . . . . . . . . . . . . . 7		2.6. Methodologies . . . . . . . . . . . . . . . . . . . . . . 9
	2.7. Errors and Uncertainties: . . . . . . . . . . . . . . . . 8		2.7. Errors and Uncertainties . . . . . . . . . . . . . . . . 10
	2.8. Reporting the metric: . . . . . . . . . . . . . . . . . . 9		2.8. Reporting the Metric . . . . . . . . . . . . . . . . . . 11
	2.8.1. Type-P . . . . . . . . . . . . . . . . . . . . . . . 10		2.8.1. Type-P . . . . . . . . . . . . . . . . . . . . . . . 11
	2.8.2. Loss Threshold . . . . . . . . . . . . . . . . . . . 10		2.8.2. Loss Threshold . . . . . . . . . . . . . . . . . . . 11
	2.8.3. Calibration Results . . . . . . . . . . . . . . . . . 10		2.8.3. Calibration Results . . . . . . . . . . . . . . . . . 11
	2.8.4. Path . . . . . . . . . . . . . . . . . . . . . . . . 10		2.8.4. Path . . . . . . . . . . . . . . . . . . . . . . . . 12
	3. A Definition for Samples of One-way Packet Loss . . . . . . . 11		3. A Definition for Samples of One-Way Packet Loss . . . . . . . 12
	3.1. Metric Name: . . . . . . . . . . . . . . . . . . . . . . 11		3.1. Metric Name . . . . . . . . . . . . . . . . . . . . . . . 12
	3.2. Metric Parameters: . . . . . . . . . . . . . . . . . . . 11		3.2. Metric Parameters . . . . . . . . . . . . . . . . . . . . 13
	3.3. Metric Units: . . . . . . . . . . . . . . . . . . . . . . 11		3.3. Metric Units . . . . . . . . . . . . . . . . . . . . . . 13
	3.4. Definition: . . . . . . . . . . . . . . . . . . . . . . . 12		3.4. Definition . . . . . . . . . . . . . . . . . . . . . . . 13
	3.5. Discussion: . . . . . . . . . . . . . . . . . . . . . . . 12		3.5. Discussion . . . . . . . . . . . . . . . . . . . . . . . 13
	3.6. Methodologies: . . . . . . . . . . . . . . . . . . . . . 13		3.6. Methodologies . . . . . . . . . . . . . . . . . . . . . . 14
	3.7. Errors and Uncertainties: . . . . . . . . . . . . . . . . 13		3.7. Errors and Uncertainties . . . . . . . . . . . . . . . . 15
	3.8. Reporting the metric: . . . . . . . . . . . . . . . . . . 14		3.8. Reporting the Metric . . . . . . . . . . . . . . . . . . 15
	4. Some Statistics Definitions for One-way Packet Loss . . . . . 14		4. Some Statistics Definitions for One-Way Packet Loss . . . . . 15
	4.1. Type-P-One-way-Packet Loss-Ratio . . . . . . . . . . . . 14		4.1. Type-P-One-way-Packet-Loss-Ratio . . . . . . . . . . . . 15
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 15		5. Security Considerations . . . . . . . . . . . . . . . . . . . 16
	6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 16		6. Changes from RFC 2680 . . . . . . . . . . . . . . . . . . . . 17
	7. Changes from RFC 2680 . . . . . . . . . . . . . . . . . . . . 16		7. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18		7.1. Normative References . . . . . . . . . . . . . . . . . . 19
	9. References . . . . . . . . . . . . . . . . . . . . . . . . . 18		7.2. Informative References . . . . . . . . . . . . . . . . . 20
	9.1. Normative References . . . . . . . . . . . . . . . . . . 18		Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 21
	9.2. Informative References . . . . . . . . . . . . . . . . . 19		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
	1. Introduction		1. Introduction
	This memo defines a metric for one-way packet loss across Internet		This memo defines a metric for one-way packet loss across Internet
	paths. It builds on notions introduced and discussed in the IPPM		paths. It builds on notions introduced and discussed in the IPPM
	Framework document, [RFC2330]; the reader is assumed to be familiar		Framework document, [RFC2330]; the reader is assumed to be familiar
	with that document, and its recent update [RFC7312].		with that document and its recent update [RFC7312].
	This memo is intended to be parallel in structure to a companion		This memo is intended to be parallel in structure to a companion
	document for One-way Delay ("A One-way Delay Metric for IPPM")		document for One-way Delay ("A One-Way Delay Metric for IP
	[RFC2679]; the reader is assumed to be familiar with that document.		Performance Metrics (IPPM)") [RFC7679]; the reader is assumed to be
			familiar with that document.
	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[RFC2119]. Although		document are to be interpreted as described in [RFC2119]. Although
	[RFC2119] was written with protocols in mind, the key words are used		[RFC2119] was written with protocols in mind, the key words are used
	in this document for similar reasons. They are used to ensure the		in this document for similar reasons. They are used to ensure the
	results of measurements from two different implementations are		results of measurements from two different implementations are
	comparable, and to note instances when an implementation could		comparable and to note instances when an implementation could perturb
	perturb the network.		the network.
			Whenever a technical term from the IPPM Framework document is first
			used in this memo, it will be tagged with a trailing asterisk. For
			example, "term*" indicates that "term" is defined in the Framework
			document.
	The structure of the memo is as follows:		The structure of the memo is as follows:
	+ A 'singleton' analytic metric, called Type-P-One-way-Packet-Loss,		o A 'singleton*' analytic metric, called Type-P-One-way-Packet-Loss,
	is introduced to measure a single observation of packet transmission		is introduced to measure a single observation of packet
	or loss.		transmission or loss.
	+ Using this singleton metric, a 'sample', called Type-P-One-way-		o Using this singleton metric, a 'sample*' called Type-P-One-way-
	Packet-Loss-Poisson-Stream, is introduced to measure a sequence of		Packet-Loss-Poisson-Stream is introduced to measure a sequence of
	singleton transmissions and/or losses measured at times taken from a		singleton transmissions and/or losses measured at times taken from
	Poisson process.		a Poisson process, as defined in Section 11.1.1 of [RFC2330].
	+ Using this sample, several 'statistics' of the sample are defined		o Using this sample, several 'statistics*' of the sample will be
	and discussed.		defined and discussed.
	This progression from singleton to sample to statistics, with clear		This progression from singleton to sample to statistics, with clear
	separation among them, is important.		separation among them, is important.
	Whenever a technical term from the IPPM Framework document is first
	used in this memo, it will be tagged with a trailing asterisk. For
	example, "term*" indicates that "term" is defined in the Framework.
	1.1. Motivation		1.1. Motivation
	Understanding one-way packet loss of Type-P* packets from a source		Understanding one-way packet loss of Type-P* packets from a source
	host* to a destination host is useful for several reasons:		host* to a destination host is useful for several reasons:
	+ Some applications do not perform well (or at all) if end-to-end		o Some applications do not perform well (or at all) if end-to-end
	loss between hosts is large relative to some threshold value.		loss between hosts is large relative to some threshold value.
	+ Excessive packet loss may make it difficult to support certain		o Excessive packet loss may make it difficult to support certain
	real-time applications (where the precise threshold of "excessive"		real-time applications (where the precise threshold of "excessive"
	depends on the application).		depends on the application).
	+ The larger the value of packet loss, the more difficult it is for		o The larger the value of packet loss, the more difficult it is for
	transport-layer protocols to sustain high bandwidths.		transport-layer protocols to sustain high bandwidths.
	+ The sensitivity of real-time applications and of transport-layer		o The sensitivity of real-time applications and of transport-layer
	protocols to loss become especially important when very large delay-		protocols to loss become especially important when very large
	bandwidth products must be supported.		delay-bandwidth products must be supported.
	The measurement of one-way loss instead of round-trip loss is		The measurement of one-way loss instead of round-trip loss is
	motivated by the following factors:		motivated by the following factors:
	+ In today's Internet, the path from a source to a destination may be		o In today's Internet, the path from a source to a destination may
	different than the path from the destination back to the source		be different than the path from the destination back to the source
	("asymmetric paths"), such that different sequences of routers are		("asymmetric paths"), such that different sequences of routers are
	used for the forward and reverse paths. Therefore round-trip		used for the forward and reverse paths. Therefore, round-trip
	measurements actually measure the performance of two distinct paths		measurements actually measure the performance of two distinct
	together. Measuring each path independently highlights the		paths together. Measuring each path independently highlights the
	performance difference between the two paths which may traverse		performance difference between the two paths that may traverse
	different Internet service providers, and even radically different		different Internet service providers and even radically different
	types of networks (for example, research versus commodity networks,		types of networks (for example, research versus commodity
	or networks with asymmetric link capacities, or wireless vs. wireline		networks, or networks with asymmetric link capacities, or wireless
	access).		versus wireline access).
	+ Even when the two paths are symmetric, they may have radically		o Even when the two paths are symmetric, they may have radically
	different performance characteristics due to asymmetric queueing.		different performance characteristics due to asymmetric queuing.
	+ Performance of an application may depend mostly on the performance		o Performance of an application may depend mostly on the performance
	in one direction. For example, a TCP-based communication will		in one direction. For example, a TCP-based communication will
	experience reduced throughput if congestion occurs in one direction		experience reduced throughput if congestion occurs in one
	of its communication. Trouble shooting may be simplified if the		direction of its communication. Troubleshooting may be simplified
	congested direction of TCP transmission can be identified.		if the congested direction of TCP transmission can be identified.
	+ In quality-of-service (QoS) enabled networks, provisioning in one		o In networks in which quality of service (QoS) is enabled,
	direction may be radically different than provisioning in the reverse		provisioning in one direction may be radically different than
	direction, and thus the QoS guarantees differ. Measuring the paths		provisioning in the reverse direction and thus the QoS guarantees
	independently allows the verification of both guarantees.		differ. Measuring the paths independently allows the verification
			of both guarantees.
	It is outside the scope of this document to say precisely how loss		It is outside the scope of this document to say precisely how loss
	metrics would be applied to specific problems.		metrics would be applied to specific problems.
	1.2. General Issues Regarding Time		1.2. General Issues regarding Time
	{Comment: the terminology below differs from that defined by ITU-T		{Comment: The terminology below differs from that defined by ITU-T
	documents (e.g., G.810, "Definitions and terminology for		documents (e.g., G.810, "Definitions and terminology for
	synchronization networks" and I.356, "B-ISDN ATM layer cell transfer		synchronization networks" and I.356, "B-ISDN ATM layer cell transfer
	performance"), but is consistent with the IPPM Framework document.		performance") but is consistent with the IPPM Framework document. In
	In general, these differences derive from the different backgrounds;		general, these differences derive from the different backgrounds; the
	the ITU-T documents historically have a telephony origin, while the		ITU-T documents historically have a telephony origin, while the
	authors of this document (and the Framework) have a computer systems		authors of this document (and the Framework document) have a computer
	background. Although the terms defined below have no direct		systems background. Although the terms defined below have no direct
	equivalent in the ITU-T definitions, after our definitions we will		equivalent in the ITU-T definitions, after our definitions we will
	provide a rough mapping. However, note one potential confusion: our		provide a rough mapping. However, note one potential confusion: our
	definition of "clock" is the computer operating systems definition		definition of "clock" is the computer operating systems definition
	denoting a time-of-day clock, while the ITU-T definition of clock		denoting a time-of-day clock, while the ITU-T definition of clock
	denotes a frequency reference.}		denotes a frequency reference.}
	Whenever a time (i.e., a moment in history) is mentioned here, it is		Whenever a time (i.e., a moment in history) is mentioned here, it is
	understood to be measured in seconds (and fractions) relative to UTC.		understood to be measured in seconds (and fractions) relative to UTC.
	As described more fully in the Framework document, there are four		As described more fully in the Framework document, there are four
	skipping to change at page 5, line 32		skipping to change at page 6, line 45
	error".}		error".}
	accuracy*		accuracy*
	measures the extent to which a given clock agrees with UTC. For		measures the extent to which a given clock agrees with UTC. For
	example, the clock on a host might be 27.1 msec behind UTC. {Comment:		example, the clock on a host might be 27.1 msec behind UTC. {Comment:
	A rough ITU-T equivalent is "time error from UTC".}		A rough ITU-T equivalent is "time error from UTC".}
	resolution*		resolution*
	specification of the smallest unit by which the clock's time is		is a specification of the smallest unit by which the clock's time is
	updated. It gives a lower bound on the clock's uncertainty. For		updated. It gives a lower bound on the clock's uncertainty. For
	example, the clock on an old Unix host might tick only once every 10		example, the clock on an old Unix host might tick only once every 10
	msec, and thus have a resolution of only 10 msec. {Comment: A very		msec and thus have a resolution of only 10 msec. {Comment: A very
	rough ITU-T equivalent is "sampling period".}		rough ITU-T equivalent is "sampling period".}
	skew*		skew*
	measures the change of accuracy, or of synchronization, with time.		measures the change of accuracy, or of synchronization, with time.
	For example, the clock on a given host might gain 1.3 msec per hour		For example, the clock on a given host might gain 1.3 msec per hour
	and thus be 27.1 msec behind UTC at one time and only 25.8 msec an		and thus be 27.1 msec behind UTC at one time and only 25.8 msec an
	hour later. In this case, we say that the clock of the given host		hour later. In this case, we say that the clock of the given host
	has a skew of 1.3 msec per hour relative to UTC, which threatens		has a skew of 1.3 msec per hour relative to UTC, which threatens
	accuracy. We might also speak of the skew of one clock relative to		accuracy. We might also speak of the skew of one clock relative to
	another clock, which threatens synchronization. {Comment: A rough		another clock, which threatens synchronization. {Comment: A rough
	ITU-T equivalent is "time drift".}		ITU-T equivalent is "time drift".}
	skipping to change at page 6, line 5		skipping to change at page 7, line 15
	measures the change of accuracy, or of synchronization, with time.		measures the change of accuracy, or of synchronization, with time.
	For example, the clock on a given host might gain 1.3 msec per hour		For example, the clock on a given host might gain 1.3 msec per hour
	and thus be 27.1 msec behind UTC at one time and only 25.8 msec an		and thus be 27.1 msec behind UTC at one time and only 25.8 msec an
	hour later. In this case, we say that the clock of the given host		hour later. In this case, we say that the clock of the given host
	has a skew of 1.3 msec per hour relative to UTC, which threatens		has a skew of 1.3 msec per hour relative to UTC, which threatens
	accuracy. We might also speak of the skew of one clock relative to		accuracy. We might also speak of the skew of one clock relative to
	another clock, which threatens synchronization. {Comment: A rough		another clock, which threatens synchronization. {Comment: A rough
	ITU-T equivalent is "time drift".}		ITU-T equivalent is "time drift".}
	2. A Singleton Definition for One-way Packet Loss		2. A Singleton Definition for One-Way Packet Loss
	2.1. Metric Name:		2.1. Metric Name
	Type-P-One-way-Packet-Loss		Type-P-One-way-Packet-Loss
	2.2. Metric Parameters:		2.2. Metric Parameters
	+ Src, the IP address of a host		o Src, the IP address of a host
	+ Dst, the IP address of a host		o Dst, the IP address of a host
	+ T, a time		o T, a time
	+ Tmax, a loss threshold waiting time		o Tmax, a loss threshold waiting time
	2.3. Metric Units:		2.3. Metric Units
	The value of a Type-P-One-way-Packet-Loss is either a zero		The value of a Type-P-One-way-Packet-Loss is either a zero
	(signifying successful transmission of the packet) or a one		(signifying successful transmission of the packet) or a one
	(signifying loss).		(signifying loss).
	2.4. Definition:		2.4. Definition
	>>The *Type-P-One-way-Packet-Loss* from Src to Dst at T is 0<< means		>>The *Type-P-One-way-Packet-Loss* from Src to Dst at T is 0<< means
	that Src sent the first bit of a Type-P packet to Dst at wire-time* T		that Src sent the first bit of a Type-P packet to Dst at wire time* T
	and that Dst received that packet.		and that Dst received that packet.
	>>The *Type-P-One-way-Packet-Loss* from Src to Dst at T is 1<< means		>>The *Type-P-One-way-Packet-Loss* from Src to Dst at T is 1<< means
	that Src sent the first bit of a type-P packet to Dst at wire-time T		that Src sent the first bit of a Type-P packet to Dst at wire time T
	and that Dst did not receive that packet (within the loss threshold		and that Dst did not receive that packet (within the loss threshold
	waiting time, Tmax).		waiting time, Tmax).
	2.5. Discussion:		2.5. Discussion
	Thus, Type-P-One-way-Packet-Loss is 0 exactly when Type-P-One-way-		Thus, Type-P-One-way-Packet-Loss is 0 exactly when Type-P-One-way-
	Delay is a finite value, and it is 1 exactly when Type-P-One-way-		Delay is a finite value, and it is 1 exactly when Type-P-One-way-
	Delay is undefined.		Delay is undefined.
	The following issues are likely to come up in practice:		The following issues are likely to come up in practice:
	+ A given methodology will have to include a way to distinguish		o A given methodology will have to include a way to distinguish
	between a packet loss and a very large (but finite) delay. As noted		between a packet loss and a very large (but finite) delay. As
	by Mahdavi and Paxson [RFC2678], simple upper bounds (such as the 255		noted by Mahdavi and Paxson [RFC2678], simple upper bounds (such
	seconds theoretical upper bound on the lifetimes of IP packets		as the 255-second theoretical upper bound on the lifetimes of IP
	[RFC0791]) could be used, but good engineering, including an		packets [RFC791]) could be used, but good engineering, including
	understanding of packet lifetimes, will be needed in practice.		an understanding of packet lifetimes, will be needed in practice.
	{Comment: Note that, for many applications of these metrics, there		{Comment: Note that, for many applications of these metrics, there
	may be no harm in treating a large delay as packet loss. An audio		may be no harm in treating a large delay as packet loss. An audio
	playback packet, for example, that arrives only after the playback		playback packet, for example, that arrives only after the playback
	point may as well have been lost. See section 4.1.1 of [RFC6703] for		point may as well have been lost. See Section 4.1.1 of [RFC6703]
	examination of unusual packet delays and application performance		for examination of unusual packet delays and application
	estimation.}		performance estimation.}
	+ If the packet arrives, but is corrupted, then it is counted as		o If the packet arrives but is corrupted, then it is counted as
	lost. {Comment: one is tempted to count the packet as received since		lost. {Comment: One is tempted to count the packet as received
	corruption and packet loss are related but distinct phenomena. If		since corruption and packet loss are related but distinct
	the IP header is corrupted, however, one cannot be sure about the		phenomena. If the IP header is corrupted, however, one cannot be
	source or destination IP addresses and is thus on shaky grounds about		sure about the source or destination IP addresses and is thus on
	knowing that the corrupted received packet corresponds to a given		shaky grounds about knowing that the corrupted received packet
	sent test packet. Similarly, if other parts of the packet needed by		corresponds to a given sent test packet. Similarly, if other
	the methodology to know that the corrupted received packet		parts of the packet needed by the methodology to know that the
	corresponds to a given sent test packet, then such a packet would		corrupted received packet corresponds to a given sent test packet,
	have to be counted as lost. Counting these packets as lost but		then such a packet would have to be counted as lost. It would be
	packet with corruption in other parts of the packet as not lost would		inconsistent to count packets with corrupted methodology-specific
	be inconsistent.} Section 15 of [RFC2330] defines the "standard-		fields as lost, and not to count packets with other corrupted
	formed" packet which is applicable to all metrics. Note: At this		aspects in the same category.} Section 15 of [RFC2330] defines the
	time, the definition of standard-formed packets only applies to IPv4,		"standard-formed" packet that is applicable to all metrics. Note
	but also see [I-D.morton-ippm-2330-stdform-typep].		that at this time the definition of standard-formed packets only
			applies to IPv4 (see also [IPPM-UPDATES]).
	+ If the packet is duplicated along the path (or paths) so that		o If the packet is duplicated along the path (or paths) so that
	multiple non-corrupt copies arrive at the destination, then the		multiple non-corrupt copies arrive at the destination, then the
	packet is counted as received.		packet is counted as received.
	+ If the packet is fragmented and if, for whatever reason, reassembly		o If the packet is fragmented and if, for whatever reason,
	does not occur, then the packet will be deemed lost.		reassembly does not occur, then the packet will be deemed lost.
	2.6. Methodologies:		2.6. Methodologies
	As with other Type-P-* metrics, the detailed methodology will depend		As with other Type-P-* metrics, the detailed methodology will depend
	on the Type-P (e.g., protocol number, UDP/TCP port number, size,		on the Type-P (e.g., protocol number, UDP/TCP port number, size,
	Differentiated Services (DS) Field [RFC2780])).		Differentiated Services (DS) Field [RFC2780]).
	Generally, for a given Type-P, one possible methodology would proceed		Generally, for a given Type-P, one possible methodology would proceed
	as follows:		as follows:
	+ Arrange that Src and Dst have clocks that are synchronized with		o Arrange that Src and Dst have clocks that are synchronized with
	each other. The degree of synchronization is a parameter of the		each other. The degree of synchronization is a parameter of the
	methodology, and depends on the threshold used to determine loss (see		methodology and depends on the threshold used to determine loss
	below).		(see below).
	+ At the Src host, select Src and Dst IP addresses, and form a test		o At the Src host, select Src and Dst IP addresses and form a test
	packet of Type-P with these addresses.		packet of Type-P with these addresses.
	+ At the Dst host, arrange to receive the packet.		o At the Dst host, arrange to receive the packet.
	+ At the Src host, place a timestamp in the prepared Type-P packet,		o At the Src host, place a timestamp in the prepared Type-P packet,
	and send it towards Dst (ideally minimizing time before sending).		and send it towards Dst (ideally minimizing time before sending).
	+ If the packet arrives within a reasonable period of time, the one-		o If the packet arrives within a reasonable period of time, the one-
	way packet-loss is taken to be zero (and take a timestamp as soon as		way packet loss is taken to be zero (and take a timestamp as soon
	possible upon the receipt of the packet).		as possible upon the receipt of the packet).
	+ If the packet fails to arrive within a reasonable period of time,		o If the packet fails to arrive within a reasonable period of time,
	Tmax, the one-way packet-loss is taken to be one. Note that the		Tmax, the one-way packet loss is taken to be one. Note that the
	threshold of "reasonable" here is a parameter of the metric.		threshold of "reasonable" here is a parameter of the metric.
	{Comment: The definition of reasonable is intentionally vague, and is		{Comment: The definition of reasonable is intentionally vague and is
	intended to indicate a value "Th" so large that any value in the		intended to indicate a value "Th" so large that any value in the
	closed interval [Th-delta, Th+delta] is an equivalent threshold for		closed interval [Th-delta, Th+delta] is an equivalent threshold for
	loss. Here, delta encompasses all error in clock synchronization and		loss. Here, delta encompasses all error in clock synchronization and
	timestamp acquisition and assignment along the measured path. If		timestamp acquisition and assignment along the measured path. If
	there is a single value, Tmax, after which the packet must be counted		there is a single value, Tmax, after which the packet must be counted
	as lost, then we reintroduce the need for a degree of clock		as lost, then we reintroduce the need for a degree of clock
	synchronization similar to that needed for one-way delay, and		synchronization similar to that needed for one-way delay, and
	virtually all practical measurement systems combine methods for delay		virtually all practical measurement systems combine methods for delay
	and loss. Therefore, if a measure of packet loss parameterized by a		and loss. Therefore, if a measure of packet loss parameterized by a
	specific non-huge "reasonable" time-out value is needed, one can		specific non-huge "reasonable" time-out value is needed, one can
	skipping to change at page 8, line 40		skipping to change at page 10, line 10
	undefined delay to packets that fail to arrive with the difficulties		undefined delay to packets that fail to arrive with the difficulties
	emerging from the informal "infinite delay" assignment, and an		emerging from the informal "infinite delay" assignment, and an
	estimation of an upper bound on waiting time for packets in transit.		estimation of an upper bound on waiting time for packets in transit.
	Further, enforcing a specific constant waiting time on stored		Further, enforcing a specific constant waiting time on stored
	singletons of one-way delay is compliant with this specification and		singletons of one-way delay is compliant with this specification and
	may allow the results to serve more than one reporting audience.}		may allow the results to serve more than one reporting audience.}
	Issues such as the packet format, the means by which Dst knows when		Issues such as the packet format, the means by which Dst knows when
	to expect the test packet, and the means by which Src and Dst are		to expect the test packet, and the means by which Src and Dst are
	synchronized are outside the scope of this document. {Comment: We		synchronized are outside the scope of this document. {Comment: We
	plan to document elsewhere our own work in describing such more		plan to document the implementation techniques of our work in much
	detailed implementation techniques and we encourage others to as		more detail elsewhere; we encourage others to do so as well.}
	well.}
	2.7. Errors and Uncertainties:		2.7. Errors and Uncertainties
	The description of any specific measurement method should include an		The description of any specific measurement method should include an
	accounting and analysis of various sources of error or uncertainty.		accounting and analysis of various sources of error or uncertainty.
	The Framework document provides general guidance on this point.		The Framework document provides general guidance on this point.
	For loss, there are three sources of error:		For loss, there are three sources of error:
	+ Synchronization between clocks on Src and Dst.		o synchronization between clocks on Src and Dst.
	+ The packet-loss threshold (which is related to the synchronization		o the packet-loss threshold (which is related to the synchronization
	between clocks).		between clocks).
	+ Resource limits in the network interface or software on the		o resource limits in the network interface or software on the
	receiving instrument.		receiving instrument.
	The first two sources are interrelated and could result in a test		The first two sources are interrelated and could result in a test
	packet with finite delay being reported as lost. Type-P-One-way-		packet with finite delay being reported as lost. Type-P-One-way-
	Packet-Loss is 1 if the test packet does not arrive, or if it does		Packet-Loss is 1 if the test packet does not arrive, or if it does
	arrive and the difference between Src timestamp and Dst timestamp is		arrive and the difference between the Src timestamp and the Dst
	greater than the "reasonable period of time", or loss threshold. If		timestamp is greater than the "reasonable period of time" or loss
	the clocks are not sufficiently synchronized, the loss threshold may		threshold. If the clocks are not sufficiently synchronized, the loss
	not be "reasonable" - the packet may take much less time to arrive		threshold may not be "reasonable" - the packet may take much less
	than its Src timestamp indicates. Similarly, if the loss threshold		time to arrive than its Src timestamp indicates. Similarly, if the
	is set too low, then many packets may be counted as lost. The loss		loss threshold is set too low, then many packets may be counted as
	threshold must be high enough, and the clocks synchronized well		lost. The loss threshold must be high enough and the clocks
	enough so that a packet that arrives is rarely counted as lost. (See		synchronized well enough so that a packet that arrives is rarely
	the discussions in the previous two sections.)		counted as lost. (See the discussions in the previous two sections.)
	Since the sensitivity of packet loss measurement alone to lack of		Since the sensitivity of packet-loss measurement alone to lack of
	clock synchronization is less than for delay, we refer the reader to		clock synchronization is less than for delay, we refer the reader to
	the treatment of synchronization errors in the One-way Delay metric		the treatment of synchronization errors in the "One-way Delay Metric
	[RFC2330] for more details.		for IPPM" [RFC2330] for more details.
	The last source of error, resource limits, cause the packet to be		The last source of error, resource limits, cause the packet to be
	dropped by the measurement instrument, and counted as lost when in		dropped by the measurement instrument and counted as lost when in
	fact the network delivered the packet in reasonable time.		fact the network delivered the packet in reasonable time.
	The measurement instruments should be calibrated such that the loss		The measurement instruments should be calibrated such that the loss
	threshold is reasonable for application of the metrics and the clocks		threshold is reasonable for application of the metrics and the clocks
	are synchronized enough so the loss threshold remains reasonable.		are synchronized enough so the loss threshold remains reasonable.
	In addition, the instruments should be checked to ensure the that the		In addition, the instruments should be checked to ensure that the
	possibility a packet arrives at the network interface, but is lost		possibility a packet arrives at the network interface but is lost due
	due to congestion on the interface or to other resource exhaustion		to congestion on the interface or to other resource exhaustion (e.g.,
	(e.g., buffers) on the instrument is low.		buffers) on the instrument is low.
	2.8. Reporting the metric:		2.8. Reporting the Metric
	The calibration and context in which the metric is measured MUST be		The calibration and context in which the metric is measured MUST be
	carefully considered, and SHOULD always be reported along with metric		carefully considered and SHOULD always be reported along with metric
	results. We now present four items to consider: Type-P of the test		results. We now present four items to consider: Type-P of the test
	packets, the loss threshold, instrument calibration, and the path		packets, the loss threshold, instrument calibration, and the path
	traversed by the test packets. This list is not exhaustive; any		traversed by the test packets. This list is not exhaustive; any
	additional information that could be useful in interpreting		additional information that could be useful in interpreting
	applications of the metrics should also be reported (see [RFC6703]		applications of the metrics should also be reported (see [RFC6703]
	for extensive discussion of reporting considerations for different		for extensive discussion of reporting considerations for different
	audiences).		audiences).
	2.8.1. Type-P		2.8.1. Type-P
	As noted in the Framework document, section 13 of [RFC2330], the		As noted in Section 13 of the Framework document [RFC2330], the value
	value of the metric may depend on the type of IP packets used to make		of the metric may depend on the type of IP packets used to make the
	the measurement, or "Type-P". The value of Type-P-One-way-Delay		measurement, or "Type-P". The value of Type-P-One-way-Delay could
	could change if the protocol (UDP or TCP), port number, size, or		change if the protocol (UDP or TCP), port number, size, or
	arrangement for special treatment (e.g., IP DS Field [RFC2780], ECN		arrangement for special treatment (e.g., IP DS Field [RFC2780],
	[RFC3168], or RSVP) changes. Additional packet distinctions		Explicit Congestion Notification (ECN) [RFC3168], or RSVP) changes.
	identified in future extensions of the Type-P definition will apply.		Additional packet distinctions identified in future extensions of the
	The exact Type-P used to make the measurements MUST be accurately		Type-P definition will apply. The exact Type-P used to make the
	reported.		measurements MUST be accurately reported.
	2.8.2. Loss Threshold		2.8.2. Loss Threshold
	The threshold, Tmax, (or methodology to distinguish) between a large		The threshold, Tmax, between a large finite delay and loss (or other
	finite delay and loss MUST be reported.		methodology to distinguish between finite delay and loss) MUST be
			reported.
	2.8.3. Calibration Results		2.8.3. Calibration Results
	The degree of synchronization between the Src and Dst clocks MUST be		The degree of synchronization between the Src and Dst clocks MUST be
	reported. If possible, possibility that a test packet that arrives		reported. If possible, a test packet that arrives at the Dst network
	at the Dst network interface is reported as lost due to resource		interface and is reported as lost due to resource exhaustion on Dst
	exhaustion on Dst SHOULD be reported.		SHOULD be reported.
	2.8.4. Path		2.8.4. Path
	Finally, the path traversed by the packet SHOULD be reported, if		Finally, the path traversed by the packet SHOULD be reported, if
	possible. In general it is impractical to know the precise path a		possible. In general, it is impractical to know the precise path a
	given packet takes through the network. The precise path may be		given packet takes through the network. The precise path may be
	known for certain Type-P on short or stable paths. If Type-P		known for certain Type-P on short or stable paths. If Type-P
	includes the record route (or loose-source route) option in the IP		includes the record route (or loose-source route) option in the IP
	header, and the path is short enough, and all routers* on the path		header, and the path is short enough, and all routers* on the path
	support record (or loose-source) route, then the path will be		support record (or loose-source) route, then the path will be
	precisely recorded. This is impractical because the route must be		precisely recorded. This is impractical because the route must be
	short enough, many routers do not support (or are not configured for)		short enough, many routers do not support (or are not configured for)
	record route, and use of this feature would often artificially worsen		record route, and use of this feature would often artificially worsen
	the performance observed by removing the packet from common-case		the performance observed by removing the packet from common-case
	processing. However, partial information is still valuable context.		processing. However, partial information is still valuable context.
	For example, if a host can choose between two links* (and hence two		For example, if a host can choose between two links* (and hence, two
	separate routes from Src to Dst), then the initial link used is		separate routes from Src to Dst), then the initial link used is
	valuable context. {Comment: Backbone path selection services come and		valuable context. {Comment: Backbone path selection services come and
	go. A historical example was Merit's NetNow setup, where a Src on		go. A historical example was Merit's NetNow setup, where a Src on
	one NAP can reach a Dst on another NAP by either of several different		one Network Access Point (NAP) can reach a Dst on another NAP by
	backbone networks.}		either of several different backbone networks.}
	3. A Definition for Samples of One-way Packet Loss		3. A Definition for Samples of One-Way Packet Loss
	Given the singleton metric Type-P-One-way-Packet-Loss, we now define		Given the singleton metric Type-P-One-way-Packet-Loss, we now define
	one particular sample of such singletons. The idea of the sample is		one particular sample of such singletons. The idea of the sample is
	to select a particular binding of the parameters Src, Dst, and Type-		to select a particular binding of the parameters Src, Dst, and Type-
	P, then define a sample of values of parameter T. The means for		P, then define a sample of values of parameter T. The means for
	defining the values of T is to select a beginning time T0, a final		defining the values of T is to select a beginning time T0, a final
	time Tf, and an average rate lambda, then define a pseudo-random		time Tf, and an average rate lambda, then define a pseudorandom
	Poisson process of rate lambda, whose values fall between T0 and Tf.		Poisson process of rate lambda, whose values fall between T0 and Tf.
	The time interval between successive values of T will then average 1/		The time interval between successive values of T will then average 1/
	lambda.		lambda.
	Note that Poisson sampling is only one way of defining a sample.		Note that Poisson sampling is only one way of defining a sample.
	Poisson has the advantage of limiting bias, but other methods of		Poisson has the advantage of limiting bias, but other methods of
	sampling will be appropriate for different situations. For example,		sampling will be appropriate for different situations. For example,
	a truncated Poisson distribution may be needed to avoid reactive		a truncated Poisson distribution may be needed to avoid reactive
	network state changes during intervals of inactivity, see section 4.6		network state changes during intervals of inactivity, see Section 4.6
	of [RFC7312]. Sometimes, the goal is sampling with a known bias, and		of [RFC7312]. Sometimes the goal is sampling with a known bias, and
	[RFC3432] describes a method for periodic sampling with random start		[RFC3432] describes a method for periodic sampling with random start
	times.		times.
	3.1. Metric Name:		3.1. Metric Name
	Type-P-One-way-Packet-Loss-Poisson-Stream		Type-P-One-way-Packet-Loss-Poisson-Stream
	3.2. Metric Parameters:		3.2. Metric Parameters
	+ Src, the IP address of a host		o Src, the IP address of a host
	+ Dst, the IP address of a host		o Dst, the IP address of a host
	+ T0, a time		o T0, a time
	+ Tf, a time		o Tf, a time
	+ Tmax, a loss threshold waiting time		o Tmax, a loss threshold waiting time
	+ lambda, a rate in reciprocal seconds		o lambda, a rate in reciprocal seconds
	3.3. Metric Units:		3.3. Metric Units
	A sequence of pairs; the elements of each pair are:		A sequence of pairs; the elements of each pair are:
	+ T, a time, and		o T, a time, and
			o L, either a zero or a one.
	+ L, either a zero or a one
	The values of T in the sequence are monotonic increasing. Note that		The values of T in the sequence are monotonic increasing. Note that
	T would be a valid parameter to Type-P-One-way-Packet-Loss, and that		T would be a valid parameter to Type-P-One-way-Packet-Loss and that L
	L would be a valid value of Type-P-One-way-Packet-Loss.		would be a valid value of Type-P-One-way-Packet-Loss.
	3.4. Definition:		3.4. Definition
	Given T0, Tf, and lambda, we compute a pseudo-random Poisson process		Given T0, Tf, and lambda, we compute a pseudorandom Poisson process
	beginning at or before T0, with average arrival rate lambda, and		beginning at or before T0, with average arrival rate lambda, and
	ending at or after Tf. Those time values greater than or equal to T0		ending at or after Tf. Those time values greater than or equal to T0
	and less than or equal to Tf are then selected. At each of the times		and less than or equal to Tf are then selected. At each of the
	in this process, we obtain the value of Type-P-One-way-Packet-Loss at		selected times in this process, we obtain one value of Type-P-One-
	this time. The value of the sample is the sequence made up of the		way-Delay. The value of the sample is the sequence made up of the
	resulting <time, loss> pairs. If there are no such pairs, the		resulting <time, loss> pairs. If there are no such pairs, the
	sequence is of length zero and the sample is said to be empty.		sequence is of length zero and the sample is said to be empty.
	3.5. Discussion:		3.5. Discussion
	The reader should be familiar with the in-depth discussion of Poisson		The reader should be familiar with the in-depth discussion of Poisson
	sampling in the Framework document [RFC2330], which includes methods		sampling in the Framework document [RFC2330], which includes methods
	to compute and verify the pseudo-random Poisson process.		to compute and verify the pseudorandom Poisson process.
	We specifically do not constrain the value of lambda, except to note		We specifically do not constrain the value of lambda except to note
	the extremes. If the rate is too large, then the measurement traffic		the extremes. If the rate is too large, then the measurement traffic
	will perturb the network, and itself cause congestion. If the rate		will perturb the network and itself cause congestion. If the rate is
	is too small, then you might not capture interesting network		too small, then you might not capture interesting network behavior.
	behavior. {Comment: We expect to document our experiences with, and		{Comment: We expect to document our experiences with, and suggestions
	suggestions for, lambda elsewhere, culminating in a "best current		for, lambda elsewhere, culminating in a "Best Current Practice"
	practices" document.}		document.}
	Since a pseudo-random number sequence is employed, the sequence of		Since a pseudorandom number sequence is employed, the sequence of
	times, and hence the value of the sample, is not fully specified.		times, and hence the value of the sample, is not fully specified.
	Pseudo-random number generators of good quality will be needed to		Pseudorandom number generators of good quality will be needed to
	achieve the desired qualities.		achieve the desired qualities.
	The sample is defined in terms of a Poisson process both to avoid the		The sample is defined in terms of a Poisson process both to avoid the
	effects of self-synchronization and also capture a sample that is		effects of self-synchronization and also capture a sample that is
	statistically as unbiased as possible. The Poisson process is used		statistically as unbiased as possible. The Poisson process is used
	to schedule the loss measurements. The test packets will generally		to schedule the loss measurements. The test packets will generally
	not arrive at Dst according to a Poisson distribution, since they are		not arrive at Dst according to a Poisson distribution, since they are
	influenced by the network. Time-slotted links described in section		influenced by the network. Time-slotted links described in
	3.4 [RFC7312] can greatly modify the sample characteristics. The		Section 3.4 [RFC7312] can greatly modify the sample characteristics.
	main concern is that un-biased packet streams with randomized inter-		The main concern is that unbiased packet streams with randomized
	packet time intervals will be converted to some new distribution		inter-packet time intervals will be converted to some new
	after encountering a time-slotted links, possibly with strong		distribution after encountering a time-slotted link, possibly with
	periodic characteristics instead.		strong periodic characteristics instead.
	{Comment: there is, of course, no claim that real Internet traffic		{Comment: there is, of course, no claim that real Internet traffic
	arrives according to a Poisson arrival process.		arrives according to a Poisson arrival process.
	It is important to note that, in contrast to this metric, loss ratios		It is important to note that, in contrast to this metric, loss ratios
	observed by transport connections do not reflect unbiased samples.		observed by transport connections do not reflect unbiased samples.
	For example, TCP transmissions both (1) occur in bursts, which can		For example, TCP transmissions both (1) occur in bursts, which can
	induce loss due to the burst volume that would not otherwise have		induce loss due to the burst volume that would not otherwise have
	been observed, and (2) adapt their transmission rate in an attempt to		been observed, and (2) adapt their transmission rate in an attempt to
	minimize the loss ratio observed by the connection.}		minimize the loss ratio observed by the connection.}
	All the singleton Type-P-One-way-Packet-Loss metrics in the sequence		All the singleton Type-P-One-way-Packet-Loss metrics in the sequence
	will have the same values of Src, Dst, and Type-P.		will have the same values of Src, Dst, and Type-P.
	Note also that, given one sample that runs from T0 to Tf, and given		Note also that, given one sample that runs from T0 to Tf, and given
	new time values T0' and Tf' such that T0 <= T0' <= Tf' <= Tf, the		new time values T0' and Tf' such that T0 <= T0' <= Tf' <= Tf, the
	subsequence of the given sample whose time values fall between T0'		subsequence of the given sample whose time values fall between T0'
	and Tf' are also a valid Type-P-One-way-Packet-Loss-Poisson-Stream		and Tf' are also a valid Type-P-One-way-Packet-Loss-Poisson-Stream
	sample.		sample.
	3.6. Methodologies:		3.6. Methodologies
	The methodologies follow directly from:		The methodologies follow directly from:
	+ the selection of specific times, using the specified Poisson		o the selection of specific times using the specified Poisson
	arrival process, and		arrival process, and
	+ the methodologies discussion already given for the singleton Type-		o the methodologies discussion already given for the singleton Type-
	P-One-way-Packet-Loss metric.		P-One-way-Packet-Loss metric.
	Care must be given to correctly handle out-of-order arrival of test		Care must be given to correctly handle out-of-order arrival of test
	packets; it is possible that the Src could send one test packet at		packets; it is possible that the Src could send one test packet at
	TS[i], then send a second one (later) at TS[i+1], while the Dst could		TS[i], then send a second one (later) at TS[i+1] while the Dst could
	receive the second test packet at TR[i+1], and then receive the first		receive the second test packet at TR[i+1], and then receive the first
	one (later) at TR[i]. Metrics for reordering may be found in		one (later) at TR[i]. Metrics for reordering may be found in
	[RFC4737].		[RFC4737].
	3.7. Errors and Uncertainties:		3.7. Errors and Uncertainties
	In addition to sources of errors and uncertainties associated with		In addition to sources of errors and uncertainties associated with
	methods employed to measure the singleton values that make up the		methods employed to measure the singleton values that make up the
	sample, care must be given to analyze the accuracy of the Poisson		sample, care must be given to analyze the accuracy of the Poisson
	arrival process of the wire-times of the sending of the test packets.		arrival process of the wire times of the sending of the test packets.
	Problems with this process could be caused by several things,		Problems with this process could be caused by several things,
	including problems with the pseudo-random number techniques used to		including problems with the pseudorandom number techniques used to
	generate the Poisson arrival process. The Framework document shows		generate the Poisson arrival process. The Framework document shows
	how to use the Anderson-Darling test to verify the accuracy of the		how to use the Anderson-Darling test to verify the accuracy of the
	Poisson process over small time frames. {Comment: The goal is to		Poisson process over small time frames. {Comment: The goal is to
	ensure that the test packets are sent "close enough" to a Poisson		ensure that the test packets are sent "close enough" to a Poisson
	schedule, and avoid periodic behavior.}		schedule and avoid periodic behavior.}
	3.8. Reporting the metric:		3.8. Reporting the Metric
	The calibration and context for the underlying singletons MUST be		The calibration and context for the underlying singletons MUST be
	reported along with the stream. (See "Reporting the metric" for		reported along with the stream (see "Reporting the Metric"
	Type-P-One-way-Packet-Loss.)		(Section 2.8) for Type-P-One-way-Packet-Loss).
	4. Some Statistics Definitions for One-way Packet Loss		4. Some Statistics Definitions for One-Way Packet Loss
	Given the sample metric Type-P-One-way-Packet-Loss-Poisson-Stream, we		Given the sample metric Type-P-One-way-Packet-Loss-Poisson-Stream, we
	now offer several statistics of that sample. These statistics are		now offer several statistics of that sample. These statistics are
	offered mostly to be illustrative of what could be done. See		offered mostly to be illustrative of what could be done. See
	[RFC6703] for additional discussion of statistics that are relevant		[RFC6703] for additional discussion of statistics that are relevant
	to different audiences.		to different audiences.
	4.1. Type-P-One-way-Packet Loss-Ratio		4.1. Type-P-One-way-Packet-Loss-Ratio
	Given a Type-P-One-way-Packet-Loss-Poisson-Stream, the average of all		Given a Type-P-One-way-Packet-Loss-Poisson-Stream, the average of all
	the L values in the Stream is the ratio of losses to total packets in		the L values in the stream is the ratio of losses to total packets in
	the stream. In addition, the Type-P-One-way-Packet-Loss-Ratio is		the stream. In addition, the Type-P-One-way-Packet-Loss-Ratio is
	undefined if the sample is empty.		undefined if the sample is empty.
	Example: suppose we take a sample and the results are:		For example, suppose we take a sample and the results are as follows:
	Stream1 = <		Stream1 = <
	<T1, 0>		<T1, 0>
	<T2, 0>		<T2, 0>
	<T3, 1>		<T3, 1>
	<T4, 0>		<T4, 0>
	<T5, 0>		<T5, 0>
	>		>
	Then the average of loss results would be 0.2, the loss ratio.		Then, the average of loss results would be 0.2, the loss ratio.
	Note that, since healthy Internet paths should be operating at loss		Note that, since healthy Internet paths should be operating at loss
	ratios below 1% (particularly if high delay-bandwidth products are to		ratios below 1% (particularly if high delay-bandwidth products are to
	be sustained), the sample sizes needed might be larger than one would		be sustained), the sample sizes needed might be larger than one would
	like. Thus, for example, if one wants to discriminate between		like. Thus, for example, if one wants to discriminate between
	various fractions of 1% over one-minute periods, then several hundred		various fractions of 1% over one-minute periods, then several hundred
	samples per minute might be needed. This would result in larger		samples per minute might be needed. This would result in larger
	values of lambda than one would ordinarily want.		values of lambda than one would ordinarily want.
	Note that although the loss threshold should be set such that any		Note that although the loss threshold should be set such that any
	errors in loss are not significant, if the possibility that a packet		errors in loss are not significant, if the possibility that a packet
	which arrived is counted as lost due to resource exhaustion is		that arrived is counted as lost due to resource exhaustion is
	significant compared to the loss ratio of interest, Type-P-One-way-		significant compared to the loss ratio of interest, Type-P-One-way-
	Packet-Loss-Ratio will be meaningless.		Packet-Loss-Ratio will be meaningless.
	5. Security Considerations		5. Security Considerations
	Conducting Internet measurements raises both security and privacy		Conducting Internet measurements raises both security and privacy
	concerns. This memo does not specify an implementation of the		concerns. This memo does not specify an implementation of the
	metrics, so it does not directly affect the security of the Internet		metrics, so it does not directly affect the security of the Internet
	nor of applications which run on the Internet. However,		nor of applications that run on the Internet. However,
	implementations of these metrics must be mindful of security and		implementations of these metrics must be mindful of security and
	privacy concerns.		privacy concerns.
	There are two types of security concerns: potential harm caused by		There are two types of security concerns: potential harm caused by
	the measurements, and potential harm to the measurements. The		the measurements and potential harm to the measurements. The
	measurements could cause harm because they are active, and inject		measurements could cause harm because they are active and inject
	packets into the network. The measurement parameters MUST be		packets into the network. The measurement parameters MUST be
	carefully selected so that the measurements inject trivial amounts of		carefully selected so that the measurements inject trivial amounts of
	additional traffic into the networks they measure. If they inject		additional traffic into the networks they measure. If they inject
	"too much" traffic, they can skew the results of the measurement, and		"too much" traffic, they can skew the results of the measurement and
	in extreme cases cause congestion and denial of service.		in extreme cases cause congestion and denial of service.
	The measurements themselves could be harmed by routers giving		The measurements themselves could be harmed by routers giving
	measurement traffic a different priority than "normal" traffic, or by		measurement traffic a different priority than "normal" traffic or by
	an attacker injecting artificial measurement traffic. If routers can		an attacker injecting artificial measurement traffic. If routers can
	recognize measurement traffic and treat it separately, the		recognize measurement traffic and treat it separately, the
	measurements will not reflect actual user traffic. If an attacker		measurements will not reflect actual user traffic. If an attacker
	injects artificial traffic that is accepted as legitimate, the loss		injects artificial traffic that is accepted as legitimate, the loss
	ratio will be artificially lowered. Therefore, the measurement		ratio will be artificially lowered. Therefore, the measurement
	methodologies SHOULD include appropriate techniques to reduce the		methodologies SHOULD include appropriate techniques to reduce the
	probability measurement traffic can be distinguished from "normal"		probability that measurement traffic can be distinguished from
	traffic. Authentication techniques, such as digital signatures, may		"normal" traffic. Authentication techniques, such as digital
	be used where appropriate to guard against injected traffic attacks.		signatures, may be used where appropriate to guard against injected
			traffic attacks.
	When considering privacy of those involved in measurement or those		When considering privacy of those involved in measurement or those
	whose traffic is measured, the sensitive information available to		whose traffic is measured, the sensitive information available to
	potential observers is greatly reduced when using active techniques		potential observers is greatly reduced when using active techniques
	which are within this scope of work. Passive observations of user		that are within this scope of work. Passive observations of user
	traffic for measurement purposes raise many privacy issues. We refer		traffic for measurement purposes raise many privacy issues. We refer
	the reader to the privacy considerations described in the Large Scale		the reader to the privacy considerations described in the Large Scale
	Measurement of Broadband Performance (LMAP) Framework		Measurement of Broadband Performance (LMAP) Framework [RFC7594],
	[I-D.ietf-lmap-framework], which covers active and passive		which covers active and passive techniques.
	techniques.
	Collecting measurements or using measurement results for		Collecting measurements or using measurement results for
	reconnaissance to assist in subsequent system attacks is quite		reconnaissance to assist in subsequent system attacks is quite
	common. Access to measurement results, or control of the measurement		common. Access to measurement results or control of the measurement
	systems to perform reconnaissance should be guarded against. See		systems to perform reconnaissance should be guarded against. See
	Section 7 of [I-D.ietf-lmap-framework] (security considerations of		Section 7 of [RFC7594] (the Security Considerations section of the
	the LMAP Framework) for system requirements that help to avoid		LMAP Framework) for system requirements that help to avoid
	measurement system compromise.		measurement system compromise.
	6. Acknowledgements		6. Changes from RFC 2680
	For [RFC2680], thanks are due to Matt Mathis for encouraging this
	work and for calling attention on so many occasions to the
	significance of packet loss. Thanks are due also to Vern Paxson for
	his valuable comments on early drafts, and to Garry Couch and Will
	Leland for several useful suggestions.
	For RFC 2680 bis, thanks to Joachim Fabini, Ruediger Geib, Nalini
	Elkins, and Barry Constantine for sharing their measurement
	experience as part of their careful reviews. Brian Carpenter and
	Scott Bradner provided useful feedback at IETF Last Call.
	7. Changes from RFC 2680
	Note: This section's placement currently preserves minimal
	differences between this memo and RFC 2680. The RFC Editor should
	place this section in an appropriate place.
	The text above constitutes RFC 2680 bis proposed for advancement on		The text above constitutes a revision to RFC 2680, which is now an
	the IETF Standards Track.		Internet Standard.
	[RFC7290] provides the test plan and results supporting [RFC2680]		[RFC7290] provides the test plan and results supporting [RFC2680]
	advancement along the standards track, according to the process in		advancement along the Standards Track, according to the process in
	[RFC6576]. The conclusions of [RFC7290] list four minor		[RFC6576]. The conclusions of [RFC7290] list four minor
	modifications for inclusion:		modifications for inclusion:
	1. Section 6.2.3 of [RFC7290] asserts that the assumption of post-		1. Section 6.2.3 of [RFC7290] asserts that the assumption of post-
	processing to enforce a constant waiting time threshold is		processing to enforce a constant waiting time threshold is
	compliant, and that the text of the RFC should be revised		compliant and that the text of the RFC should be revised slightly
	slightly to include this point. The applicability of post-		to include this point. The applicability of post-processing was
	processing was added in the last list item of section 2.6, above.		added in the last list item of Section 2.6, above.
	2. Section 6.5 of [RFC7290] indicates that Type-P-One-way-Packet-		2. Section 6.5 of [RFC7290] indicates that the Type-P-One-way-
	Loss-Average statistic is more commonly called Packet Loss Ratio,		Packet-Loss-Average statistic is more commonly called a Packet
	so it is re-named in RFC2680bis (this small discrepancy does not		Loss Ratio, so it is renamed in this document (this small
	affect candidacy for advancement) The re-naming was implemented		discrepancy does not affect candidacy for advancement). The
	in section 4.1, above.		renaming was implemented in Section 4.1, above.
	3. The IETF has reached consensus on guidance for reporting metrics		3. The IETF has reached consensus on guidance for reporting metrics
	in [RFC6703], and this memo should be referenced in RFC2680bis to		in [RFC6703], and the memo is referenced this document to
	incorporate recent experience where appropriate. This reference		incorporate recent experience where appropriate. This reference
	was added in the last list item of section 2.6, in section 2.8,		was added in the last list item of Section 2.6, in Section 2.8,
	and in section 4 above.		and in Section 4 above.
	4. There are currently two errata with status "Verified" and "Held		4. There are currently two errata with status "Verified" (EID 1528)
	for document update" for [RFC2680], and these minor revisions		and "Held for Document Update" (EID 3186) for [RFC2680], and
	were incorporated in section 1 and section 2.7.		these minor revisions were incorporated in Sections 1 and 2.7.
	A number of updates to the [RFC2680] text have been implemented in		A number of updates to the [RFC2680] text have been implemented in
	the text, to reference key IPPM RFCs that were approved after		the text to reference key IPPM RFCs that were approved after
	[RFC2680] (see sections 3 and 3.6, above), and to address comments on		[RFC2680] (see Sections 3 and 3.6, above) and to address comments on
	the IPPM mailing list describing current conditions and experience.		the IPPM mailing list describing current conditions and experience.
	1. Near the end of section 1.1, update of a network example using		1. Near the end of Section 1.1, there is an update of a network
	ATM and clarification of TCP's affect on queue occupation and		example using ATM, a clarification of TCP's affect on queue
	importance of one-way delay measurement.		occupation, and discussion of the importance of one-way delay
			measurement.
	2. Clarification of the definition of "resolution" in section 1.2.		2. Clarification of the definition of "resolution" in Section 1.2.
	3. Explicit inclusion of the maximum waiting time input parameter		3. Explicit inclusion of the maximum waiting time input parameter
	in sections 2.2, 2.4, and 3.2, reflecting recognition of this		in Sections 2.2, 2.4, and 3.2, reflecting recognition of this
	parameter in more recent RFCs and ITU-T Recommendation Y.1540.		parameter in more recent RFCs and ITU-T Recommendation Y.1540.
	4. Addition of reference to RFC 6703 in the discussion of packet		4. Addition of a reference to RFC 6703 in the discussion of packet
	life time and application timeouts in section 2.5.		lifetime and application timeouts in Section 2.5.
	5. Replaced "precedence" with updated terminology (DS Field) in 2.6		5. Replaced "precedence" with updated terminology (DS Field) in
	and 2.8.1 (with reference).		Sections 2.6 and 2.8.1 (with reference).
	6. Added parenthetical guidance on minimizing interval between		6. Added parenthetical guidance on minimizing the interval between
	timestamp placement to send time or reception time in section		timestamp placement to send time or reception time in
	2.6. Also, the text now recognizes the timestamp acquisition		Section 2.6. Also, the text now recognizes the timestamp
	process and that practical systems measure both delay and loss		acquisition process and that practical systems measure both
	(thus require the max waiting time parameter).		delay and loss (thus requiring the max waiting time parameter).
	7. Added reference to RFC 3432 Periodic sampling alongside Poisson		7. Added a reference to RFC 3432 regarding periodic sampling
	sampling in section 3, and also noting that a truncated Poisson		alongside Poisson sampling in Section 3 and also noted that a
	distribution may be needed with modern networks as described in		truncated Poisson distribution may be needed with modern
	the IPPM Framework update, [RFC7312].		networks as described in the IPPM Framework update [RFC7312].
	8. Recognition that Time-slotted links described in [RFC7312] can		8. Recognition that time-slotted links described in [RFC7312] can
	greatly modify the sample characteristics, in section 3.5.		greatly modify the sample characteristics, in Section 3.5.
	9. Add reference to RFC 4737 Reordering metric in the related		9. Added a reference to RFC 4737 regarding reordering metrics in
	discussion of section 3.6, Methodologies.		the related discussion of Section 3.6, "Methodologies".
	10. Expanded and updated the material on Privacy, and added cautions		10. Expanded and updated the material on privacy and added cautions
	on use of measurements for reconnaissance in section 5, Security		on use of measurements for reconnaissance in Section 5,
	Considerations.		"Security Considerations".
	Section 5.4.4 of [RFC6390] suggests a common template for performance		Section 5.4.4 of [RFC6390] suggests a common template for performance
	metrics partially derived from previous IPPM and BMWG RFCs, but also		metrics partially derived from previous IPPM and Benchmarking
	contains some new items. All of the [RFC6390] Normative points are		Methodology Working Group (BMWG) RFCs, but it also contains some new
	covered, but not quite in the same section names or orientation.		items. All of the normative parts of [RFC6390] are covered, but not
	Several of the Informative points are covered. Maintaining the		quite in the same section names or orientation. Several of the
	familiar outline of IPPM literature has value and minimizes		informative parts are covered. Maintaining the familiar outline of
	unnecessary differences between this revised RFC and current/future		IPPM literature has value and minimizes unnecessary differences
	IPPM RFCs.		between this revised RFC and current/future IPPM RFCs.
	8. IANA Considerations
	This memo makes no requests of IANA.
	9. References		7. References
	9.1. Normative References		7.1. Normative References
	[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,		[RFC791] Postel, J., "Internet Protocol", STD 5, RFC 791,
	DOI 10.17487/RFC0791, September 1981,		DOI 10.17487/RFC0791, September 1981,
	<http://www.rfc-editor.org/info/rfc791>.		<http://www.rfc-editor.org/info/rfc791>.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<http://www.rfc-editor.org/info/rfc2119>.		<http://www.rfc-editor.org/info/rfc2119>.
	[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>.
	[RFC2678] Mahdavi, J. and V. Paxson, "IPPM Metrics for Measuring		[RFC2678] Mahdavi, J. and V. Paxson, "IPPM Metrics for Measuring
	Connectivity", RFC 2678, DOI 10.17487/RFC2678, September		Connectivity", RFC 2678, DOI 10.17487/RFC2678, September
	1999, <http://www.rfc-editor.org/info/rfc2678>.		1999, <http://www.rfc-editor.org/info/rfc2678>.
	[RFC2679] Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way
	Delay Metric for IPPM", RFC 2679, DOI 10.17487/RFC2679,
	September 1999, <http://www.rfc-editor.org/info/rfc2679>.
	[RFC2680] Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way		[RFC2680] Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way
	Packet Loss Metric for IPPM", RFC 2680,		Packet Loss Metric for IPPM", RFC 2680,
	DOI 10.17487/RFC2680, September 1999,		DOI 10.17487/RFC2680, September 1999,
	<http://www.rfc-editor.org/info/rfc2680>.		<http://www.rfc-editor.org/info/rfc2680>.
	[RFC2780] Bradner, S. and V. Paxson, "IANA Allocation Guidelines For		[RFC2780] Bradner, S. and V. Paxson, "IANA Allocation Guidelines For
	Values In the Internet Protocol and Related Headers",		Values In the Internet Protocol and Related Headers",
	BCP 37, RFC 2780, DOI 10.17487/RFC2780, March 2000,		BCP 37, RFC 2780, DOI 10.17487/RFC2780, March 2000,
	<http://www.rfc-editor.org/info/rfc2780>.		<http://www.rfc-editor.org/info/rfc2780>.
	[RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
	of Explicit Congestion Notification (ECN) to IP",
	RFC 3168, DOI 10.17487/RFC3168, September 2001,
	<http://www.rfc-editor.org/info/rfc3168>.
	[RFC3432] Raisanen, V., Grotefeld, G., and A. Morton, "Network		[RFC3432] Raisanen, V., Grotefeld, G., and A. Morton, "Network
	performance measurement with periodic streams", RFC 3432,		performance measurement with periodic streams", RFC 3432,
	DOI 10.17487/RFC3432, November 2002,		DOI 10.17487/RFC3432, November 2002,
	<http://www.rfc-editor.org/info/rfc3432>.		<http://www.rfc-editor.org/info/rfc3432>.
	[RFC6576] Geib, R., Ed., Morton, A., Fardid, R., and A. Steinmitz,		[RFC6576] Geib, R., Ed., Morton, A., Fardid, R., and A. Steinmitz,
	"IP Performance Metrics (IPPM) Standard Advancement		"IP Performance Metrics (IPPM) Standard Advancement
	Testing", BCP 176, RFC 6576, DOI 10.17487/RFC6576, March		Testing", BCP 176, RFC 6576, DOI 10.17487/RFC6576, March
	2012, <http://www.rfc-editor.org/info/rfc6576>.		2012, <http://www.rfc-editor.org/info/rfc6576>.
	[RFC7312] Fabini, J. and A. Morton, "Advanced Stream and Sampling		[RFC7312] Fabini, J. and A. Morton, "Advanced Stream and Sampling
	Framework for IP Performance Metrics (IPPM)", RFC 7312,		Framework for IP Performance Metrics (IPPM)", RFC 7312,
	DOI 10.17487/RFC7312, August 2014,		DOI 10.17487/RFC7312, August 2014,
	<http://www.rfc-editor.org/info/rfc7312>.		<http://www.rfc-editor.org/info/rfc7312>.
	9.2. Informative References		[RFC7679] Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton,
			Ed., "A One-Way Delay Metric for IP Performance Metrics
			(IPPM)", STD 81, RFC 7679, DOI 10.17487/RFC7679, January
			2016, <http://www.rfc-editor.org/info/rfc7679>.
	[I-D.ietf-lmap-framework]		7.2. Informative References
	Eardley, P., Morton, A., Bagnulo, M., Burbridge, T.,
	Aitken, P., and A. Akhter, "A framework for Large-Scale
	Measurement of Broadband Performance (LMAP)", draft-ietf-
	lmap-framework-14 (work in progress), April 2015.
	[I-D.morton-ippm-2330-stdform-typep]		[IPPM-UPDATES]
	Morton, A., Fabini, J., Elkins, N., Ackermann, M., and V.		Morton, A., Fabini, J., Elkins, N., Ackermann, M., and V.
	Hegde, "Updates for IPPM's Active Metric Framework:		Hegde, "Updates for IPPM's Active Metric Framework:
	Packets of Type-P and Standard-Formed Packets", draft-		Packets of Type-P and Standard-Formed Packets", Work in
	morton-ippm-2330-stdform-typep-00 (work in progress),		Progress, draft-morton-ippm-2330-stdform-typep-02,
	August 2015.		December 2015.
			[RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
			of Explicit Congestion Notification (ECN) to IP",
			RFC 3168, DOI 10.17487/RFC3168, September 2001,
			<http://www.rfc-editor.org/info/rfc3168>.
	[RFC4737] Morton, A., Ciavattone, L., Ramachandran, G., Shalunov,		[RFC4737] Morton, A., Ciavattone, L., Ramachandran, G., Shalunov,
	S., and J. Perser, "Packet Reordering Metrics", RFC 4737,		S., and J. Perser, "Packet Reordering Metrics", RFC 4737,
	DOI 10.17487/RFC4737, November 2006,		DOI 10.17487/RFC4737, November 2006,
	<http://www.rfc-editor.org/info/rfc4737>.		<http://www.rfc-editor.org/info/rfc4737>.
	[RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New		[RFC6390] Clark, A. and B. Claise, "Guidelines for Considering New
	Performance Metric Development", BCP 170, RFC 6390,		Performance Metric Development", BCP 170, RFC 6390,
	DOI 10.17487/RFC6390, October 2011,		DOI 10.17487/RFC6390, October 2011,
	<http://www.rfc-editor.org/info/rfc6390>.		<http://www.rfc-editor.org/info/rfc6390>.
	skipping to change at page 20, line 15		skipping to change at page 21, line 15
	[RFC6703] Morton, A., Ramachandran, G., and G. Maguluri, "Reporting		[RFC6703] Morton, A., Ramachandran, G., and G. Maguluri, "Reporting
	IP Network Performance Metrics: Different Points of View",		IP Network Performance Metrics: Different Points of View",
	RFC 6703, DOI 10.17487/RFC6703, August 2012,		RFC 6703, DOI 10.17487/RFC6703, August 2012,
	<http://www.rfc-editor.org/info/rfc6703>.		<http://www.rfc-editor.org/info/rfc6703>.
	[RFC7290] Ciavattone, L., Geib, R., Morton, A., and M. Wieser, "Test		[RFC7290] Ciavattone, L., Geib, R., Morton, A., and M. Wieser, "Test
	Plan and Results for Advancing RFC 2680 on the Standards		Plan and Results for Advancing RFC 2680 on the Standards
	Track", RFC 7290, DOI 10.17487/RFC7290, July 2014,		Track", RFC 7290, DOI 10.17487/RFC7290, July 2014,
	<http://www.rfc-editor.org/info/rfc7290>.		<http://www.rfc-editor.org/info/rfc7290>.
			[RFC7594] Eardley, P., Morton, A., Bagnulo, M., Burbridge, T.,
			Aitken, P., and A. Akhter, "A Framework for Large-Scale
			Measurement of Broadband Performance (LMAP)", RFC 7594,
			DOI 10.17487/RFC7594, September 2015,
			<http://www.rfc-editor.org/info/rfc7594>.
			Acknowledgements
			For [RFC2680], thanks are due to Matt Mathis for encouraging this
			work and for calling attention on so many occasions to the
			significance of packet loss. Thanks are due also to Vern Paxson for
			his valuable comments on early drafts and to Garry Couch and Will
			Leland for several useful suggestions.
			For this document, thanks to Joachim Fabini, Ruediger Geib, Nalini
			Elkins, and Barry Constantine for sharing their measurement
			experience as part of their careful reviews. Brian Carpenter and
			Scott Bradner provided useful feedback at IETF Last Call.
	Authors' Addresses		Authors' Addresses
	Guy Almes		Guy Almes
	Texas A&M		Texas A&M
	Email: almes@acm.org		Email: almes@acm.org
	Sunil Kalidindi		Sunil Kalidindi
	Ixia		Ixia
	skipping to change at page 20, line 36		skipping to change at page 22, line 26
	Matt Zekauskas		Matt Zekauskas
	Internet2		Internet2
	Email: matt@internet2.edu		Email: matt@internet2.edu
	Al Morton (editor)		Al Morton (editor)
	AT&T Labs		AT&T Labs
	200 Laurel Avenue South		200 Laurel Avenue South
	Middletown, NJ 07748		Middletown, NJ 07748
	USA		United States
	Phone: +1 732 420 1571		Phone: +1 732 420 1571
	Fax: +1 732 368 1192		Fax: +1 732 368 1192
	Email: acmorton@att.com		Email: acmorton@att.com
	URI: http://home.comcast.net/~acmacm/		URI: http://home.comcast.net/~acmacm/
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