draft-ietf-ippm-framework-compagg-01.txt   draft-ietf-ippm-framework-compagg-02.txt 
Network Working Group A. Morton, Ed. Network Working Group A. Morton, Ed.
Internet-Draft AT&T Labs Internet-Draft AT&T Labs
Expires: December 26, 2006 S. Van den Berghe, Ed. Intended status: Informational S. Van den Berghe, Ed.
Ghent University - IBBT Expires: April 25, 2007 Ghent University - IBBT
June 24, 2006 October 22, 2006
Framework for Metric Composition Framework for Metric Composition
draft-ietf-ippm-framework-compagg-01 draft-ietf-ippm-framework-compagg-01
Status of this Memo Status of this Memo
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2006). Copyright (C) The Internet Society (2006).
Abstract Abstract
This memo describes a framework for composing and aggregating metrics This memo describes a framework for composing and aggregating metrics
(both in time and in space) defined by RFC 2330 and developed by the (both in time and in space) defined by RFC 2330 and developed by the
IPPM working group. The framework describes the generic composition IPPM working group. The framework describes the generic composition
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1. Reducing Measurement Overhead . . . . . . . . . . . . 3 1.1.1. Reducing Measurement Overhead . . . . . . . . . . . . 3
1.1.2. Measurement Re-use . . . . . . . . . . . . . . . . . . 4 1.1.2. Measurement Re-use . . . . . . . . . . . . . . . . . . 4
1.1.3. Data Reduction and Consolidation . . . . . . . . . . . 4 1.1.3. Data Reduction and Consolidation . . . . . . . . . . . 4
1.1.4. Implications on Measurement Design and Reporting . . . 5 1.1.4. Implications on Measurement Design and Reporting . . . 5
2. Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . 5 2. Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . 5
3. Description of Metric Types . . . . . . . . . . . . . . . . . 5 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Temporal Aggregation Description . . . . . . . . . . . . . 5 3.1. Measurement Point . . . . . . . . . . . . . . . . . . . . 5
3.2. Spatial Aggregation Description . . . . . . . . . . . . . 6 3.2. Complete path . . . . . . . . . . . . . . . . . . . . . . 6
3.3. Spatial Composition Description . . . . . . . . . . . . . 7 3.3. Complete path metric . . . . . . . . . . . . . . . . . . . 6
3.4. Help Metrics . . . . . . . . . . . . . . . . . . . . . . . 7 3.4. Composed Metric . . . . . . . . . . . . . . . . . . . . . 6
3.5. Higher Order Composition . . . . . . . . . . . . . . . . . 7 3.5. Composition Function . . . . . . . . . . . . . . . . . . . 6
4. Requirements for Composed Metrics . . . . . . . . . . . . . . 7 3.6. Ground Truth . . . . . . . . . . . . . . . . . . . . . . . 6
5. Guidelines for Defining Composed Metrics . . . . . . . . . . . 9 3.7. Sub-interval . . . . . . . . . . . . . . . . . . . . . . . 6
5.1. Ground Truth: Comparison with other IPPM Metrics . . . . . 9 3.8. Sub-path . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.2. Deviation from the Ground Truth . . . . . . . . . . . . . 11 3.9. Sub-path metrics . . . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 4. Description of Metric Types . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 4.1. Temporal Aggregation Description . . . . . . . . . . . . . 7
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 4.2. Spatial Aggregation Description . . . . . . . . . . . . . 7
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.3. Spatial Composition Description . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . . 12 4.4. Help Metrics . . . . . . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . . 13 4.5. Higher Order Composition . . . . . . . . . . . . . . . . . 9
5. Requirements for Composed Metrics . . . . . . . . . . . . . . 9
6. Guidelines for Defining Composed Metrics . . . . . . . . . . . 10
6.1. Ground Truth: Comparison with other IPPM Metrics . . . . . 10
6.1.1. Ground Truth for Temporal Aggregation . . . . . . . . 12
6.1.2. Ground Truth for Spatial Aggregation . . . . . . . . . 13
6.2. Deviation from the Ground Truth . . . . . . . . . . . . . 13
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
8. Security Considerations . . . . . . . . . . . . . . . . . . . 13
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
10.1. Normative References . . . . . . . . . . . . . . . . . . . 14
10.2. Informative References . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
Intellectual Property and Copyright Statements . . . . . . . . . . 15 Intellectual Property and Copyright Statements . . . . . . . . . . 16
1. Introduction 1. Introduction
The IPPM framework RFC 2330 [RFC2330] describes two forms of metric The IPPM framework [RFC2330] describes two forms of metric
composition, spatial and temporal. Also, the text suggests that the composition, spatial and temporal. Also, the text suggests that the
concepts of the analytical framework (or A-frame) would help to concepts of the analytical framework (or A-frame) would help to
develop useful relationships to derive the composed metrics from real develop useful relationships to derive the composed metrics from real
metrics. The effectiveness of composed metrics is dependent on their metrics. The effectiveness of composed metrics is dependent on their
usefulness in analysis and applicability to practical measurement usefulness in analysis and applicability to practical measurement
circumstances. circumstances.
This memo expands on the notion of composition, and provides a This memo expands on the notion of composition, and provides a
detailed framework for several classes of metrics that were mentioned detailed framework for several classes of metrics that were mentioned
in the original IPPM framework. The classes include temporal in the original IPPM framework. The classes include temporal
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1.1. Motivation 1.1. Motivation
Network operators have deployed measurement systems to serve many Network operators have deployed measurement systems to serve many
purposes, including performance monitoring, maintenance support, purposes, including performance monitoring, maintenance support,
network engineering, and customer reporting. The collection of network engineering, and customer reporting. The collection of
elementary measurements alone is not enough to understand a network's elementary measurements alone is not enough to understand a network's
behaviour. In general, measurements need to be post-processed to behaviour. In general, measurements need to be post-processed to
present the most relevant information for each purpose. The first present the most relevant information for each purpose. The first
step is often a process of "composition" of single measurements or step is often a process of "composition" of single measurements or
measurement sets into other forms. Composition and aggregation measurement sets into other forms. Composition and aggregation
present several more post-processing opportunites to the network present several more post-processing opportunities to the network
operator, and we describe the key motivations below. operator, and we describe the key motivations below.
1.1.1. Reducing Measurement Overhead 1.1.1. Reducing Measurement Overhead
A network's measurement possibilities scale upward with the square of A network's measurement possibilities scale upward with the square of
the number of nodes. But each measurement implies overhead, in terms the number of nodes. But each measurement implies overhead, in terms
of the storage for the results, the traffic on the network (assuming of the storage for the results, the traffic on the network (assuming
active methods), and the OA&M for the measurement system itself. In active methods), and the OA&M for the measurement system itself. In
a large network, it is impossible to perform measurements from each a large network, it is impossible to perform measurements from each
node to all others. node to all others.
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from primary metrics using a deterministic function. Key information from primary metrics using a deterministic function. Key information
about each metric, such as its assumptions under which the about each metric, such as its assumptions under which the
relationship holds, and possible sources of error/circumstances where relationship holds, and possible sources of error/circumstances where
the composition may fail, are included. the composition may fail, are included.
At this time, the scope of effort is limited to the metrics for At this time, the scope of effort is limited to the metrics for
packet loss, delay, and delay variation. Composition of packet packet loss, delay, and delay variation. Composition of packet
reordering metrics is considered a research topic, and beyond the reordering metrics is considered a research topic, and beyond the
scope at the time this memo was prepared. scope at the time this memo was prepared.
This memo will retain the terminology of the IPPM Framework as much This memo will retain the terminology of the IPPM Framework
as possible, but will extend the terminology when necessary. [RFC2330]as much as possible, but will extend the terminology when
necessary. It is assumed that the reader is familiar with the
concepts introduced in [RFC2330], as they will not be repeated here.
3. Description of Metric Types 3. Terminology
This section defines the terminology applicable to the processes of
Metric Composition and Aggregation.
3.1. Measurement Point
The logical or physical location where packet observations are made.
The term Measurement Point is synonymous with the term "observation
position" used in [RFC2330] when describing the notion of wire time.
A measurement point may be at the boundary between a host and an
adjacent link (physical), or it may be within a host (logical) that
performs measurements where the difference between host time and wire
time is understood.
3.2. Complete path
The complete path is the true path that a packet would follow as it
traverses from the packet's Source to its Destination.
3.3. Complete path metric
The complete path metric is the Source to Destination metric that a
composed metric is estimating. A complete path metric represents the
ground-truth for a composed metric.
3.4. Composed Metric
A composed metric is derived from other metrics principally by
applying a composition function.
3.5. Composition Function
A composition function is a deterministic process applied to Sub-path
metrics to derive another metric (such as a Composed metric).
3.6. Ground Truth
As applied here, the notion of ground truth is defined as the actual
performance of a network entity over some time interval. The ground
truth is the (unavailable) measurement that a composed metric seeks
to estimate.
3.7. Sub-interval
A Sub-interval is a time interval that is included in another
interval.
3.8. Sub-path
A Sub-path is a portion of the complete path where at least the Sub-
path Source and Destination hosts are constituents of the complete
path. We say that this sub-path is "involved" in the complete path.
3.9. Sub-path metrics
A sub-path path metric is an element of the process to derive a
Composite metric, quantifying some aspect of the performance a
particular sub-path from its Source to Destination.
4. Description of Metric Types
This section defines the various classes of Composition. There are This section defines the various classes of Composition. There are
two classes more accurately referred to as aggregation over time and two classes more accurately referred to as aggregation over time and
space, and the third is simply composition in space. space, and the third is simply composition in space.
3.1. Temporal Aggregation Description 4.1. Temporal Aggregation Description
Aggregation in time is defined as the composition of metrics with the Aggregation in time is defined as the composition of metrics with the
same type and scope obtained in different time instants or time same type and scope obtained in different time instants or time
windows. For example, starting from a time series of One-Way Delay windows. For example, starting from a time series of One-Way Delay
measurements on a certain network path obtained in 5-minute periods measurements on a certain network path obtained in 5-minute periods
and averaging groups of 12 consecutive values, we obtain a time and averaging groups of 12 consecutive values, we obtain a time
series measurement with a coarser resolution (60 minutes). The main series measurement with a coarser resolution (60 minutes). The main
reason for doing time aggregation is to reduce the amount of data reason for doing time aggregation is to reduce the amount of data
that has to be stored, and make the visualization/spotting of regular that has to be stored, and make the visualization/spotting of regular
cycles and/or growing or decreasing trends easier. Another useful cycles and/or growing or decreasing trends easier. Another useful
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In RFC 2330, the term "temporal composition" is introduced and In RFC 2330, the term "temporal composition" is introduced and
differs from temporal aggregation in that it refers to methodologies differs from temporal aggregation in that it refers to methodologies
to predict future metrics on the basis of past observations, to predict future metrics on the basis of past observations,
exploiting the time correlation that certain metrics can exhibit. We exploiting the time correlation that certain metrics can exhibit. We
do not consider this type of composition here. do not consider this type of composition here.
>>>>>>>>Comment: Why no forecasting? This was apparently a limit on >>>>>>>>Comment: Why no forecasting? This was apparently a limit on
the Geant2 project, but may not apply here. the Geant2 project, but may not apply here.
3.2. Spatial Aggregation Description 4.2. Spatial Aggregation Description
Aggregation in space is defined as the combination of metrics of the Aggregation in space is defined as the combination of metrics of the
same type and different scope, in order to estimate the overall same type and different scope, in order to estimate the overall
performance of a larger domain. This combination may involve performance of a larger domain. This combination may involve
weighing the contributions of the input metrics. weighing the contributions of the input metrics.
Suppose we want to compose the average One-Way-Delay (OWD) Suppose we want to compose the average One-Way-Delay (OWD)
experienced by flows traversing all the Origin-Destination (OD) pairs experienced by flows traversing all the Origin-Destination (OD) pairs
of a network domain (where the inputs are already metric of a network domain (where the inputs are already metric
"statistics"). Since we wish to include the effect of the traffic "statistics"). Since we wish to include the effect of the traffic
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We suggest that space aggregation is generally useful to obtain a We suggest that space aggregation is generally useful to obtain a
summary view of the behaviour of large network portions, or in summary view of the behaviour of large network portions, or in
general of coarser aggregates. The metric collection time instant, general of coarser aggregates. The metric collection time instant,
i.e. the metric collection time window of measured metrics is not i.e. the metric collection time window of measured metrics is not
considered in space aggregation. We assume that either it is considered in space aggregation. We assume that either it is
consistent for all the composed metrics, e.g. compose a set of consistent for all the composed metrics, e.g. compose a set of
average delays all referred to the same time window, or the time average delays all referred to the same time window, or the time
window of each composed metric does not affect aggregated metric. window of each composed metric does not affect aggregated metric.
3.3. Spatial Composition Description 4.3. Spatial Composition Description
Concatenation in space is defined as the composition of metrics of Concatenation in space is defined as the composition of metrics of
same type and (ideally) different spatial scope, so that the same type and (ideally) different spatial scope, so that the
resulting metric is representative of what the metric would be if resulting metric is representative of what the metric would be if
obtained with a direct measurement over the sequence of the several obtained with a direct measurement over the sequence of the several
spatial scopes. An example is the sum of OWDs of different edge-to- spatial scopes. An example is the sum of OWDs of different edge-to-
edge domain's delays, where the intermediate edge points are close to edge domain's delays, where the intermediate edge points are close to
each other or happen to be the same. In this way, we can for example each other or happen to be the same. In this way, we can for example
estimate OWD_AC starting from the knowledge of OWD_AB and OWD_BC. estimate OWD_AC starting from the knowledge of OWD_AB and OWD_BC.
Note that there may be small gaps in measurement coverage, likewise Note that there may be small gaps in measurement coverage, likewise
there may be small overlaps (e.g., the link where test equipment there may be small overlaps (e.g., the link where test equipment
connects to the network). connects to the network).
One key difference from examples of aggregation in space is that all One key difference from examples of aggregation in space is that all
sub-paths contribute equally to the composed metric, independent of sub-paths contribute equally to the composed metric, independent of
the traffic load present. the traffic load present.
3.4. Help Metrics 4.4. Help Metrics
Finally, note that in practice there is often the need of extracting Finally, note that in practice there is often the need of extracting
a new metric making some computation over one or more metrics with a new metric making some computation over one or more metrics with
the same spatial and time scope. For example, the composed metric the same spatial and time scope. For example, the composed metric
rtt_sample_variance may be composed from two different metrics: the rtt_sample_variance may be composed from two different metrics: the
help metric rtt_square_sum and the statistical metric rtt_sum. This help metric rtt_square_sum and the statistical metric rtt_sum. This
operation is however more a simple calculation and not an aggregation operation is however more a simple calculation and not an aggregation
or a concatenation, and we'll not investigate it further in this or a concatenation, and we'll not investigate it further in this
memo. memo.
3.5. Higher Order Composition 4.5. Higher Order Composition
Composed metrics might themselves be subject to further steps of Composed metrics might themselves be subject to further steps of
composition or aggregation. An example would be a the delay of a composition or aggregation. An example would be a the delay of a
maximal domain obtained through the spatial composition of several maximal domain obtained through the spatial composition of several
composed end-to-end delays (obtained through spatial composition). composed end-to-end delays (obtained through spatial composition).
All requirements for first order composition metrics apply to higher All requirements for first order composition metrics apply to higher
order composition. order composition.
>>>>> Comment Response: are more examples needed here? >>>>> Comment Response: are more examples needed here?
4. Requirements for Composed Metrics 5. Requirements for Composed Metrics
The definitions for all composed metrics MUST include sections to The definitions for all composed metrics MUST include sections to
treat the following topics. treat the following topics.
The description of each metric will clearly state: The description of each metric will clearly state:
1. the definition (and statistic, where appropriate); 1. the definition (and statistic, where appropriate);
2. the composition or aggregation relationship; 2. the composition or aggregation relationship;
3. the specific conjecture on which the relationship is based; 3. the specific conjecture on which the relationship is based;
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o Requires precisely synchronized measurement time intervals in all o Requires precisely synchronized measurement time intervals in all
component metrics, or loosely synchronized, or no timing component metrics, or loosely synchronized, or no timing
requirements. requirements.
o Requires assumption of component metric independence w.r.t. the o Requires assumption of component metric independence w.r.t. the
metric being defined/composed, or other assumptions. metric being defined/composed, or other assumptions.
o Has known sources of inaccuracy/error, and identifies the sources. o Has known sources of inaccuracy/error, and identifies the sources.
5. Guidelines for Defining Composed Metrics 6. Guidelines for Defining Composed Metrics
5.1. Ground Truth: Comparison with other IPPM Metrics 6.1. Ground Truth: Comparison with other IPPM Metrics
Figure 1 illustrates the process to derive a metric using spatial Figure 1 illustrates the process to derive a metric using spatial
composition, and compares the composed metric to other IPPM metrics. composition, and compares the composed metric to other IPPM metrics.
Metrics <M1, M2, M3> describe the performance of sub-paths between Metrics <M1, M2, M3> describe the performance of sub-paths between
the Source and Destination of interest during time interval <T, Tf>. the Source and Destination of interest during time interval <T, Tf>.
These metrics are the inputs for a Composition Function that produces These metrics are the inputs for a Composition Function that produces
a Composed Metric. a Composed Metric.
Sub-Path Metrics Sub-Path Metrics
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Src ||...............................|| Dst Src ||...............................|| Dst
++ Composed Metric ++ ++ Composed Metric ++
++ Complete Path Metric ++ ++ Complete Path Metric ++
Src ||...............................|| Dst Src ||...............................|| Dst
++ ++ ++ ++
Spatial Metric Spatial Metric
++ S1 ++ S2 ++ S3 ++ ++ S1 ++ S2 ++ S3 ++
Src ||........||.........||..........|| Dst Src ||........||.........||..........|| Dst
++ ++ ++ ++ ++ ++ ++ ++
Figure 1 Comparison with other IPPM metrics
Figure 1: Comparison with other IPPM metrics
The Composed Metric is an estimate of an actual metric collected over The Composed Metric is an estimate of an actual metric collected over
the complete Source to Destination path. We say that the Complete the complete Source to Destination path. We say that the Complete
Path Metric represents the "Ground Truth" for the Composed Metric. Path Metric represents the "Ground Truth" for the Composed Metric.
In other words, Composed Metrics seek to minimize error w.r.t. the In other words, Composed Metrics seek to minimize error w.r.t. the
Complete Path Metric. Complete Path Metric.
Further, we observe that a Spatial Metric I-D.ietf-ippm-multimetrics Further, we observe that a Spatial Metric I-D.ietf-ippm-multimetrics
[I-D.ietf-ippm-multimetrics]collected for packets traveling over the [I-D.ietf-ippm-multimetrics]collected for packets traveling over the
same set of sub-paths provide a basis for the Ground Truth of the same set of sub-paths provide a basis for the Ground Truth of the
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Src ||........||.........||..........||Rcvr1 Src ||........||.........||..........||Rcvr1
++ ++. ++ ++ ++ ++. ++ ++
`-. `-.
`-. ++ ++ `-. ++ ++
`-||..........||Rcvr2 `-||..........||Rcvr2
++. ++ ++. ++
`-. `-.
`-. ++ `-. ++
`-.||Rcvr3 `-.||Rcvr3
++ ++
Figure 2 Composition of One-to-Group Metrics
Figure 2: Composition of One-to-Group Metrics
Here, Sub-path Metrics M1, M2, and M3 are combined using a Here, Sub-path Metrics M1, M2, and M3 are combined using a
relationship to compose the metric applicable to the Src-Rcvr1 path. relationship to compose the metric applicable to the Src-Rcvr1 path.
Similarly, M1, M4, and M5 are used to compose the Src-Rcvr2 metric Similarly, M1, M4, and M5 are used to compose the Src-Rcvr2 metric
and M1, M4, and M6 compose the Src-Rcvr3 metric. and M1, M4, and M6 compose the Src-Rcvr3 metric.
The Composed One-to-Group Metric would list the Src-Rcvr metrics for The Composed One-to-Group Metric would list the Src-Rcvr metrics for
each Receiver in the Group: each Receiver in the Group:
(Composed-Rcvr1, Composed-Rcvr2, Composed-Rcvr3) (Composed-Rcvr1, Composed-Rcvr2, Composed-Rcvr3)
The "Ground Truth" for this composed metric is of course an actual The "Ground Truth" for this composed metric is of course an actual
One-to-Group metric, where a single source packet has been measured One-to-Group metric, where a single source packet has been measured
after traversing the Complete Paths to the various receivers. after traversing the Complete Paths to the various receivers.
5.2. Deviation from the Ground Truth 6.1.1. Ground Truth for Temporal Aggregation
Temporal Aggregation involves measurements made over sub-intervals of
the desired test interval between the same Source and Destination.
Therefore, the "Ground Truth" is the metric measured over the desired
interval.
6.1.2. Ground Truth for Spatial Aggregation
Spatial Aggregation combines many measurements using a weighting
function to provide the same emphasis as though the measurements were
based on actual traffic, with inherent weights. Therefore, the
"Ground Truth" is the metric measured on the actual traffic instead
of the active streams that sample the performance.
6.2. Deviation from the Ground Truth
A metric composition can deviate from the ground truth for several A metric composition can deviate from the ground truth for several
reasons. Two main aspects are: reasons. Two main aspects are:
o The propagation of the inaccuracies of the underlying measurements o The propagation of the inaccuracies of the underlying measurements
when composing the metric. As part of the composition function, when composing the metric. As part of the composition function,
errors of measurements might propagate. Where possible, this errors of measurements might propagate. Where possible, this
analysis should be made and included with the description of each analysis should be made and included with the description of each
metric. metric.
o A difference in scope. When concatenating hop-by-hop active o A difference in scope. When concatenating hop-by-hop active
measurement results to obtain the end-to-end metric, the actual measurement results to obtain the end-to-end metric, the actual
measured path will not be identical to the end-to-end path. It is measured path will not be identical to the end-to-end path. It is
in general difficult to quantify this deviation, but a metric in general difficult to quantify this deviation, but a metric
definition might identify guidelines for keeping the deviation as definition might identify guidelines for keeping the deviation as
small as possible. small as possible.
The description of the metric composition MUST include an section The description of the metric composition MUST include an section
identifying the deviation from the ground truth. identifying the deviation from the ground truth.
6. IANA Considerations 7. IANA Considerations
This document makes no request of IANA. This document makes no request of IANA.
Note to RFC Editor: this section may be removed on publication as an Note to RFC Editor: this section may be removed on publication as an
RFC. RFC.
7. Security Considerations 8. Security Considerations
8. Acknowledgements The security considerations that apply to any active measurement of
live networks are relevant here as well. See [RFC4656].
9. Acknowledgements
The authors would like to thank Maurizio Molina, Andy Van Maele, The authors would like to thank Maurizio Molina, Andy Van Maele,
Andreas Haneman, Igor Velimirovic, Andreas Solberg, Athanassios Andreas Haneman, Igor Velimirovic, Andreas Solberg, Athanassios
Liakopulos, David Schitz, Nicolas Simar and the Geant2 Project. We Liakopulos, David Schitz, Nicolas Simar and the Geant2 Project. We
also acknowledge comments and suggestions from Phil Chimento, Emile also acknowledge comments and suggestions from Phil Chimento, Emile
Stephan and Lei Liang. Stephan and Lei Liang.
9. References 10. References
9.1. Normative References 10.1. Normative References
[I-D.ietf-ippm-multimetrics] [I-D.ietf-ippm-multimetrics]
Stephan, E., "IP Performance Metrics (IPPM) for spatial Stephan, E., "IP Performance Metrics (IPPM) for spatial
and multicast", draft-ietf-ippm-multimetrics-00 (work in and multicast", draft-ietf-ippm-multimetrics-01 (work in
progress), January 2006. progress), July 2006.
[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, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[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,
May 1998. May 1998.
9.2. Informative References [RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M.
Zekauskas, "A One-way Active Measurement Protocol
(OWAMP)", RFC 4656, September 2006.
10.2. Informative References
Authors' Addresses Authors' Addresses
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 USA
Phone: +1 732 420 1571 Phone: +1 732 420 1571
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Steven Van den Berghe (editor) Steven Van den Berghe (editor)
Ghent University - IBBT Ghent University - IBBT
G. Crommenlaan 8 bus 201 G. Crommenlaan 8 bus 201
Gent 9050 Gent 9050
Belgium Belgium
Phone: +32 9 331 49 73 Phone: +32 9 331 49 73
Email: steven.vandenberghe@intec.ugent.be Email: steven.vandenberghe@intec.ugent.be
URI: http://www.ibcn.intec.ugent.be URI: http://www.ibcn.intec.ugent.be
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INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
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to the rights, licenses and restrictions contained in BCP 78, and
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