draft-ietf-ippm-reordering-06.txt   draft-ietf-ippm-reordering-07.txt 
Network Working Group A.Morton Network Working Group A.Morton
Internet Draft L.Ciavattone Internet Draft L.Ciavattone
Document: <draft-ietf-ippm-reordering-06.txt> G.Ramachandran Document: <draft-ietf-ippm-reordering-07.txt> G.Ramachandran
Category: Standards Track AT&T Labs Category: Standards Track AT&T Labs
S.Shalunov S.Shalunov
Internet2 Internet2
J.Perser J.Perser
Consultant Consultant
Packet Reordering Metric for IPPM Packet Reordering Metric for IPPM
Status of this Memo Status of this Memo
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Abstract...........................................................1 Abstract...........................................................1
1. Conventions used in this document...............................3 1. Conventions used in this document...............................3
2. Introduction....................................................3 2. Introduction....................................................3
2.1 Motivation.....................................................4 2.1 Motivation.....................................................4
2.2 Goals and Objectives...........................................5 2.2 Goals and Objectives...........................................5
3. A Reordered Packet Singleton Metric.............................5 3. A Reordered Packet Singleton Metric.............................5
3.1 Metric Name:...................................................6 3.1 Metric Name:...................................................6
3.2 Metric Parameters:.............................................6 3.2 Metric Parameters:.............................................6
3.3 Definition:....................................................6 3.3 Definition:....................................................6
3.4 Sequence Discontinuity Definition..............................7 3.4 Sequence Discontinuity Definition..............................7
3.5 Evaluation in Time or Byte Order...............................7 3.5 Evaluation in Time or Byte Order...............................8
3.6 Discussion.....................................................8 3.6 Discussion.....................................................8
4. Sample Metrics..................................................8 4. Sample Metrics..................................................8
4.1 Reordered Packet Ratio.........................................8 4.1 Reordered Packet Ratio.........................................9
4.1.1 Metric Name:.................................................9 4.1.1 Metric Name:.................................................9
4.1.2 Metric Parameters:...........................................9 4.1.2 Metric Parameters:...........................................9
4.1.3 Definition:..................................................9 4.1.3 Definition:..................................................9
4.1.4 Discussion...................................................9 4.1.4 Discussion...................................................9
4.2 Reordering Extent..............................................9 4.2 Reordering Extent..............................................9
4.2.1 Metric Name:.................................................9 4.2.1 Metric Name:................................................10
4.2.2 Parameter Notation:..........................................9 4.2.2 Parameter Notation:.........................................10
4.2.3 Definition:.................................................10 4.2.3 Definition:.................................................10
4.2.4 Discussion:.................................................10 4.2.4 Discussion:.................................................10
4.3 Reordering Late Time Offset...................................11 4.3 Reordering Late Time Offset...................................11
4.3.1 Metric Name:................................................11 4.3.1 Metric Name:................................................11
4.3.2 Metric Parameters:..........................................11 4.3.2 Metric Parameters:..........................................11
4.3.3 Definition:.................................................11 4.3.3 Definition:.................................................11
4.3.4 Discussion..................................................11 4.3.4 Discussion..................................................12
4.4 Reordering Byte Offset........................................12 4.4 Reordering Byte Offset........................................12
4.4.1 Metric Name:................................................12 4.4.1 Metric Name:................................................12
4.4.2 Metric Parameters:..........................................12 4.4.2 Metric Parameters:..........................................12
4.4.3 Definition:.................................................12 4.4.3 Definition:.................................................12
4.4.4 Discussion..................................................12 4.4.4 Discussion..................................................13
4.5 Gaps between multiple Reordering Discontinuities..............13 4.5 Gaps between multiple Reordering Discontinuities..............13
4.5.1 Metric Name:................................................13 4.5.1 Metric Name:................................................13
4.5.2 Parameters:.................................................13 4.5.2 Parameters:.................................................13
4.5.3 Definition of Reordering Discontinuity:.....................13 4.5.3 Definition of Reordering Discontinuity:.....................13
4.5.4 Definition of Reordering Gap:...............................13 4.5.4 Definition of Reordering Gap:...............................13
4.5.5 Discussion..................................................14 4.5.5 Discussion..................................................14
4.6 Reordering-free Runs..........................................14 4.6 Reordering-free Runs..........................................14
4.6.1 Metric Name:................................................14 4.6.1 Metric Name:................................................14
4.6.2 Parameters:.................................................14 4.6.2 Parameters:.................................................14
4.6.3 Definition:.................................................14 4.6.3 Definition:.................................................15
4.6.4 Discussion:.................................................15 4.6.4 Discussion:.................................................15
5. Metrics Focused on Receiver Assessment: A TCP-Relevant Metric..16 5. Metrics Focused on Receiver Assessment: A TCP-Relevant Metric..16
5.1 Metric Name:..................................................16 5.1 Metric Name:..................................................16
5.2 Parameter Notation:...........................................16 5.2 Parameter Notation:...........................................16
5.3 Definitions...................................................16 5.3 Definitions...................................................16
5.4 Discussion:...................................................17 5.4 Discussion:...................................................17
6. Measurement and Implementation Issues..........................17 6. Measurement and Implementation Issues..........................18
7. Examples of Arrival Order Evaluation...........................20 7. Examples of Arrival Order Evaluation...........................20
7.1 Example with a single packet reordered........................20 7.1 Example with a single packet reordered........................20
7.2 Example with two packets reordered............................21 7.2 Example with two packets reordered............................22
7.3 Example with three packets reordered..........................22 7.3 Example with three packets reordered..........................23
7.4 Example with Multiple Packet Reordering Discontinuities.......23 7.4 Example with Multiple Packet Reordering Discontinuities.......24
8. Security Considerations........................................24 8. Security Considerations........................................24
8.1 Denial of Service Attacks.....................................24 8.1 Denial of Service Attacks.....................................24
8.2 User data confidentiality.....................................24 8.2 User data confidentiality.....................................25
8.3 Interference with the metric..................................24 8.3 Interference with the metric..................................25
9. IANA Considerations............................................25 9. IANA Considerations............................................25
10. Normative References..........................................25 10. Normative References..........................................25
11. Informative References........................................25 11. Informative References........................................25
12. Acknowledgments...............................................26 12. Acknowledgments...............................................26
13. Appendix A Example Implementations in C (Informative).........26 13. Appendix A Example Implementations in C (Informative).........27
14. Appendix B Fragment Order Evaluation (Informative)............28 14. Appendix B Fragment Order Evaluation (Informative)............29
14.1 Metric Name:.................................................29 14.1 Metric Name:.................................................29
14.2 Additional Metric Parameters:................................29 14.2 Additional Metric Parameters:................................29
14.3 Definition:..................................................29 14.3 Definition:..................................................30
14.4 Discussion: Notes on Sample Metrics when evaluating Fragments31 14.4 Discussion: Notes on Sample Metrics when evaluating Fragments31
15. Author's Addresses............................................31 15. Author's Addresses............................................31
Full Copyright Statement..........................................32 Full Copyright Statement..........................................32
Intellectual Property.............................................32 Intellectual Property.............................................32
Acknowledgement...................................................32 Acknowledgement...................................................33
1. Conventions used in this document 1. Conventions used in this 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 RFC 2119 [1]. document are to be interpreted as described in RFC 2119 [1].
Although RFC 2119 was written with protocols in mind, the key words Although RFC 2119 was written with protocols in mind, the key words
are used in this document for similar reasons. They are used to are used in this document for similar reasons. They are used to
ensure the results of measurements from two different ensure the results of measurements from two different
implementations are comparable, and to note instances when an implementations are comparable, and to note instances when an
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+ work even if the stream has duplicate or lost packets + work even if the stream has duplicate or lost packets
It is desirable for Reordering Metrics to have one or more of the It is desirable for Reordering Metrics to have one or more of the
following attributes: following attributes:
+ have concatenating results for segments measured separately + have concatenating results for segments measured separately
+ have simplicity for easy consumption and understanding + have simplicity for easy consumption and understanding
+ have relevance to TCP performance + have relevance to TCP performance
+ have relevance to Real-time application performance + have relevance to Real-time application performance
The current set of metrics meet all the requirements above, and
provides all but the concatenation attribute (except in the case
where segments exhibit no reordering, and one may estimate that the
segment concatenation would also exhibit this desirable outcome).
However, satisfying these goals limits the set of metrics to those
that provide some clear insight into network characterization or
receiver design, and they are not likely to be exhaustive in their
coverage of the applications with respect to packet reordering
effects. Likewise, additional measurements may be possible.
3. A Reordered Packet Singleton Metric 3. A Reordered Packet Singleton Metric
The IPPM framework RFC 2330 [2] describes the notions of singletons, The IPPM framework RFC 2330 [2] describes the notions of singletons,
samples, and statistics. For easy reference: samples, and statistics. For easy reference:
By a 'singleton' metric, we refer to metrics that are, By a 'singleton' metric, we refer to metrics that are,
in a sense, atomic. For example, a single instance of "bulk in a sense, atomic. For example, a single instance of "bulk
throughput capacity" from one host to another might be defined throughput capacity" from one host to another might be defined
as a singleton metric, even though the instance involves as a singleton metric, even though the instance involves
measuring the timing of a number of Internet packets. measuring the timing of a number of Internet packets.
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