 1/draftietfippmspatialcomposition04.txt 20071105 19:12:06.000000000 +0100
+++ 2/draftietfippmspatialcomposition05.txt 20071105 19:12:06.000000000 +0100
@@ 1,19 +1,19 @@
Network Working Group A. Morton
InternetDraft AT&T Labs
Intended status: Standards Track E. Stephan
Expires: January 8, 2008 France Telecom Division R&D
 July 7, 2007
+Expires: May 8, 2008 France Telecom Division R&D
+ November 5, 2007
Spatial Composition of Metrics
 draftietfippmspatialcomposition04
+ draftietfippmspatialcomposition05
Status of this Memo
By submitting this InternetDraft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
InternetDrafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
@@ 24,21 +24,21 @@
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use InternetDrafts as reference
material or to cite them other than as "work in progress."
The list of current InternetDrafts can be accessed at
http://www.ietf.org/ietf/1idabstracts.txt.
The list of InternetDraft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
 This InternetDraft will expire on January 8, 2008.
+ This InternetDraft will expire on May 8, 2008.
Copyright Notice
Copyright (C) The IETF Trust (2007).
Abstract
This memo utilizes IPPM metrics that are applicable to both complete
paths and subpaths, and defines relationships to compose a complete
path metric from the subpath metrics with some accuracy w.r.t. the
@@ 65,86 +65,86 @@
3.1. Scope of work . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Application . . . . . . . . . . . . . . . . . . . . . . . 6
3.3. Incomplete Information . . . . . . . . . . . . . . . . . . 6
4. Common Specifications for Composed Metrics . . . . . . . . . . 7
4.1. Name: TypeP . . . . . . . . . . . . . . . . . . . . . . . 7
4.1.1. Metric Parameters . . . . . . . . . . . . . . . . . . 7
4.1.2. Definition and Metric Units . . . . . . . . . . . . . 8
4.1.3. Discussion and other details . . . . . . . . . . . . . 8
4.1.4. Statistic: . . . . . . . . . . . . . . . . . . . . . . 8
4.1.5. Composition Function . . . . . . . . . . . . . . . . . 8
 4.1.6. Statement of Conjecture . . . . . . . . . . . . . . . 8
+ 4.1.6. Statement of Conjecture and Assumptions . . . . . . . 8
4.1.7. Justification of the Composition Function . . . . . . 8
4.1.8. Sources of Deviation from the Ground Truth . . . . . . 9
4.1.9. Specific cases where the conjecture might fail . . . . 9
4.1.10. Application of Measurement Methodology . . . . . . . . 9
5. Oneway Delay Composed Metrics and Statistics . . . . . . . . 10
5.1. Name:
TypePFiniteOnewayDelayPoisson/PeriodicStream . . . 10
5.1.1. Metric Parameters . . . . . . . . . . . . . . . . . . 10
5.1.2. Definition and Metric Units . . . . . . . . . . . . . 10
5.1.3. Discussion and other details . . . . . . . . . . . . . 10
5.2. Name: TypePFiniteCompositeOnewayDelayMean . . . . . 11
5.2.1. Metric Parameters . . . . . . . . . . . . . . . . . . 11
5.2.2. Definition and Metric Units of the Mean Statistic . . 11
5.2.3. Discussion and other details . . . . . . . . . . . . . 11
5.2.4. Composition Function: Sum of Means . . . . . . . . . . 11
 5.2.5. Statement of Conjecture . . . . . . . . . . . . . . . 12
+ 5.2.5. Statement of Conjecture and Assumptions . . . . . . . 12
5.2.6. Justification of the Composition Function . . . . . . 12
5.2.7. Sources of Deviation from the Ground Truth . . . . . . 12
5.2.8. Specific cases where the conjecture might fail . . . . 12
5.2.9. Application of Measurement Methodology . . . . . . . . 12
5.3. Name: TypePFiniteCompositeOnewayDelayMinimum . . . 12
5.3.1. Metric Parameters . . . . . . . . . . . . . . . . . . 13
5.3.2. Definition and Metric Units of the Mean Statistic . . 13
5.3.3. Discussion and other details . . . . . . . . . . . . . 13
5.3.4. Composition Function: Sum of Means . . . . . . . . . . 13
 5.3.5. Statement of Conjecture . . . . . . . . . . . . . . . 13
+ 5.3.5. Statement of Conjecture and Assumptions . . . . . . . 14
5.3.6. Justification of the Composition Function . . . . . . 14
5.3.7. Sources of Deviation from the Ground Truth . . . . . . 14
5.3.8. Specific cases where the conjecture might fail . . . . 14
5.3.9. Application of Measurement Methodology . . . . . . . . 14
6. Loss Metrics and Statistics . . . . . . . . . . . . . . . . . 14
6.1. TypePCompositeOnewayPacketLossEmpiricalProbability 14
6.1.1. Metric Parameters: . . . . . . . . . . . . . . . . . . 14
6.1.2. Definition and Metric Units . . . . . . . . . . . . . 14
6.1.3. Discussion and other details . . . . . . . . . . . . . 15
6.1.4. Statistic:
TypePOnewayPacketLossEmpiricalProbability . . . 15
6.1.5. Composition Function: Composition of Empirical
Probabilities . . . . . . . . . . . . . . . . . . . . 15
 6.1.6. Statement of Conjecture . . . . . . . . . . . . . . . 15
 6.1.7. Justification of the Composition Function . . . . . . 15
+ 6.1.6. Statement of Conjecture and Assumptions . . . . . . . 15
+ 6.1.7. Justification of the Composition Function . . . . . . 16
6.1.8. Sources of Deviation from the Ground Truth . . . . . . 16
6.1.9. Specific cases where the conjecture might fail . . . . 16
6.1.10. Application of Measurement Methodology . . . . . . . . 16
7. Delay Variation Metrics and Statistics . . . . . . . . . . . . 16
7.1. Name: TypePOnewaypdvrefminPoisson/PeriodicStream . 16
7.1.1. Metric Parameters: . . . . . . . . . . . . . . . . . . 16
7.1.2. Definition and Metric Units . . . . . . . . . . . . . 17
7.1.3. Discussion and other details . . . . . . . . . . . . . 17
 7.1.4. Statistics: Mean, Variance, Skewness, Quanitle . . . . 17
+ 7.1.4. Statistics: Mean, Variance, Skewness, Quanitle . . . . 18
7.1.5. Composition Functions: . . . . . . . . . . . . . . . . 18
 7.1.6. Statement of Conjecture . . . . . . . . . . . . . . . 19
 7.1.7. Justification of the Composition Function . . . . . . 19
 7.1.8. Sources of Deviation from the Ground Truth . . . . . . 19
+ 7.1.6. Statement of Conjecture and Assumptions . . . . . . . 19
+ 7.1.7. Justification of the Composition Function . . . . . . 20
+ 7.1.8. Sources of Deviation from the Ground Truth . . . . . . 20
7.1.9. Specific cases where the conjecture might fail . . . . 20
7.1.10. Application of Measurement Methodology . . . . . . . . 20
8. Security Considerations . . . . . . . . . . . . . . . . . . . 20
8.1. Denial of Service Attacks . . . . . . . . . . . . . . . . 20
 8.2. User Data Confidentiality . . . . . . . . . . . . . . . . 20
+ 8.2. User Data Confidentiality . . . . . . . . . . . . . . . . 21
8.3. Interference with the metrics . . . . . . . . . . . . . . 21
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
10. Issues (Open and Closed) . . . . . . . . . . . . . . . . . . . 21
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 22
 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 22
 12.1. Normative References . . . . . . . . . . . . . . . . . . . 22
+ 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
+ 12.1. Normative References . . . . . . . . . . . . . . . . . . . 23
12.2. Informative References . . . . . . . . . . . . . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23
Intellectual Property and Copyright Statements . . . . . . . . . . 25
1. Contributors
Thus far, the following people have contributed useful ideas,
suggestions, or the text of sections that have been incorporated into
this memo:
@@ 179,21 +179,23 @@
The main purpose of this memo is to define the deterministic
functions that yield the complete path metrics using metrics of the
subpaths. The effectiveness of such metrics is dependent on their
usefulness in analysis and applicability with practical measurement
methods.
The relationships may involve conjecture, and [RFC2330] lists four
points that the metric definitions should include:
 o the specific conjecture applied to the metric,
+ o the specific conjecture applied to the metric and assumptions of
+ the statistical model of the process being measured (if any, see
+ [RFC2330] section 12),
o a justification of the practical utility of the composition in
terms of making accurate measurements of the metric on the path,
o a justification of the usefulness of the composition in terms of
making analysis of the path using Aframe concepts more effective,
and
o an analysis of how the conjecture could be incorrect.
Also, [RFC2330] gives an example where a conjecture that the delay of
@@ 349,21 +351,21 @@
This section is unique for every metric.
4.1.4. Statistic:
This section is unique for every metric.
4.1.5. Composition Function
This section is unique for every metric.
4.1.6. Statement of Conjecture
+4.1.6. Statement of Conjecture and Assumptions
This section is unique for each metric.
4.1.7. Justification of the Composition Function
It is sometimes impractical to conduct active measurements between
every SrcDst pair. Since the full mesh of N measurement points
grows as N x N, the scope of measurement may be limited by testing
resources.
@@ 407,23 +409,24 @@
This section is unique for each metric.
4.1.10. Application of Measurement Methodology
The methodology:
SHOULD use similar packets sent and collected separately in each sub
path.
 Allows a degree of flexibility (e.g., active or passive methods can
 produce the "same" metric, but timing and correlation of passive
 measurements is much more challenging).
+ Allows a degree of flexibility regarding test stream generation
+ (e.g., active or passive methods can produce an equivalent result,
+ but the lack of control over the source, timing and correlation of
+ passive measurements is much more challenging).
Poisson and/or Periodic streams are RECOMMENDED.
Applies to both Interdomain and Intradomain composition.
SHOULD have synchronized measurement time intervals in all subpaths,
but largely overlapping intervals MAY suffice.
REQUIRES assumption of subpath independence w.r.t. the metric being
defined/composed.
@@ 516,28 +519,31 @@
Then the
TypePFiniteCompositeOnewayDelayMean =
S

\
CompMeanDelay = > (MeanDelay [i])
/

i = 1
5.2.5. Statement of Conjecture
+5.2.5. Statement of Conjecture and Assumptions
The mean of a sufficiently large stream of packets measured on each
subpath during the interval [T, Tf] will be representative of the
true mean of the delay distribution (and the distributions themselves
are sufficiently independent), such that the means may be added to
produce an estimate of the complete path mean delay.
+ It is assumed that the oneway delay distributions of the subpaths
+ and the complete path are continuous.
+
5.2.6. Justification of the Composition Function
See the common section.
5.2.7. Sources of Deviation from the Ground Truth
See the common section.
5.2.8. Specific cases where the conjecture might fail
@@ 597,28 +603,31 @@
TypePFiniteCompositeOnewayDelayMinimum =
S

\
CompMinDelay = > (MinDelay [i])
/

i = 1
5.3.5. Statement of Conjecture
+5.3.5. Statement of Conjecture and Assumptions
The minimum of a sufficiently large stream of packets measured on
each subpath during the interval [T, Tf] will be representative of
the true minimum of the delay distribution (and the distributions
themselves are sufficiently independent), such that the minima may be
added to produce an estimate of the complete path minimum delay.
+ It is assumed that the oneway delay distributions of the subpaths
+ and the complete path are continuous.
+
5.3.6. Justification of the Composition Function
See the common section.
5.3.7. Sources of Deviation from the Ground Truth
See the common section.
5.3.8. Specific cases where the conjecture might fail
@@ 680,28 +689,28 @@
Epn) as
TypePCompositeOnewayPacketLossEmpiricalProbability =
CompEp = 1  {(1  Ep1) x (1  Ep2) x (1  Ep3) x ... x (1  Epn)}
If any Epn is undefined in a particular measurement interval,
possibly because a measurement system failed to report a value, then
any CompEp that uses subpath n for that measurement interval is
undefined.
6.1.6. Statement of Conjecture
+6.1.6. Statement of Conjecture and Assumptions
The empirical probability of loss calculated on a sufficiently large
stream of packets measured on each subpath during the interval [T,
 Tf] will be representative of the true loss probability (and the
 probabilities themselves are sufficiently independent), such that the
 subpath probabilities may be combined to produce an estimate of the
 complete path loss probability.
+ Tf] will be representative of the true empirical loss probability
+ (and the probabilities themselves are sufficiently independent), such
+ that the subpath probabilities may be combined to produce an
+ estimate of the complete path empirical loss probability.
6.1.7. Justification of the Composition Function
See the common section.
6.1.8. Sources of Deviation from the Ground Truth
See the common section.
6.1.9. Specific cases where the conjecture might fail
@@ 863,29 +873,32 @@
distributions.
7.1.5.2. Normal Power Approximation
TypePOnewayCompositepdvrefminNPA for the complete Source to
Destination path can be calculated by combining statistics of all the
constituent subpaths in the following process:
< see [Y.1541] clause 8 and Appendix X >
7.1.6. Statement of Conjecture
+7.1.6. Statement of Conjecture and Assumptions
The delay distribution of a sufficiently large stream of packets
measured on each subpath during the interval [T, Tf] will be
sufficiently stationary and the subpath distributions themselves are
sufficiently independent, so that summary information describing the
subpath distributions can be combined to estimate the delay
distribution of complete path.
+ It is assumed that the oneway delay distributions of the subpaths
+ and the complete path are continuous.
+
7.1.7. Justification of the Composition Function
See the common section.
7.1.8. Sources of Deviation from the Ground Truth
In addition to the common deviations, a few additional sources exist
here. For one, very tight distributions with range on the order of a
few milliseconds are not accurately represented by a histogram with 1
ms bins. This size was chosen assuming an implicit requirement on
@@ 1011,45 +1024,41 @@
>>>>>>>>>>>>>>>>RESOLUTION: No and Yes.
11. Acknowledgements
12. References
12.1. Normative References
[ID.ietfippmframeworkcompagg]
 Morton, A. and S. Berghe, "Framework for Metric
 Composition", draftietfippmframeworkcompagg03 (work
 in progress), March 2007.
+ Morton, A., "Framework for Metric Composition",
+ draftietfippmframeworkcompagg04 (work in progress),
+ July 2007.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2330] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,
"Framework for IP Performance Metrics", RFC 2330,
May 1998.
[RFC2679] Almes, G., Kalidindi, S., and M. Zekauskas, "A Oneway
Delay Metric for IPPM", RFC 2679, September 1999.
[RFC2680] Almes, G., Kalidindi, S., and M. Zekauskas, "A Oneway
Packet Loss Metric for IPPM", RFC 2680, September 1999.
[RFC3393] Demichelis, C. and P. Chimento, "IP Packet Delay Variation
Metric for IP Performance Metrics (IPPM)", RFC 3393,
November 2002.
 [RFC3432] Raisanen, V., Grotefeld, G., and A. Morton, "Network
 performance measurement with periodic streams", RFC 3432,
 November 2002.

[RFC4148] Stephan, E., "IP Performance Metrics (IPPM) Metrics
Registry", BCP 108, RFC 4148, August 2005.
12.2. Informative References
[ID.ietfippmmultimetrics]
Stephan, E., "IP Performance Metrics (IPPM) for spatial
and multicast", draftietfippmmultimetrics04 (work in
progress), July 2007.