A One-Way Delay Metric for IPPM
draft-morton-ippm-2679-bis-00

Abstract

This memo defines a metric for one-way delay of packets across Internet paths. It builds on notions introduced and discussed in the IPPM Framework document, RFC 2330; the reader is assumed to be familiar with that document.

Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].

Status of This Memo

This Internet-Draft is submitted in full conformance with the 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/⁠.

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This Internet-Draft will expire on April 16, 2013.

Copyright Notice

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Table of Contents

• 1. Introduction
• 1.1. Motivation
• 1.2. General Issues Regarding Time
• 2. A Singleton Definition for One-way Delay
• 2.1. Metric Name:
• 2.2. Metric Parameters:
• 2.3. Metric Units:
• 2.4. Definition:
• 2.5. Discussion:
• 2.6. Methodologies:
• 2.7. Errors and Uncertainties:
• 2.7.1. Errors or uncertainties related to Clocks
• 2.7.2. Errors or uncertainties related to Wire-time vs Host-time
• 2.7.3. Calibration
• 2.8. Reporting the metric:
• 2.8.1. Type-P
• 2.8.2. Loss Threshold
• 2.8.3. Calibration Results
• 2.8.4. Path
• 3. A Definition for Samples of One-way Delay
• 3.1. Metric Name:
• 3.2. Metric Parameters:
• 3.3. Metric Units:
• 3.4. Definition:
• 3.5. Discussion:
• 3.6. Methodologies:
• 3.7. Errors and Uncertainties:
• 3.8. Reporting the metric:
• 4. Some Statistics Definitions for One-way Delay
• 4.1. Type-P-One-way-Delay-Percentile
• 4.2. Type-P-One-way-Delay-Median
• 4.3. Type-P-One-way-Delay-Minimum
• 4.4. Type-P-One-way-Delay-Inverse-Percentile
• 5. Security Considerations
• 6. IANA Considerations
• 7. Acknowledgements
• 8. Refetrences (temporary)
• 9. References
• 9.1. Normative References
• 9.2. Informative References
• Authors' Addresses

1. Introduction

This memo defines a metric for one-way delay of packets across Internet paths. It builds on notions introduced and discussed in the IPPM Framework document, RFC 2330 [1]; the reader is assumed to be familiar with that document.

This memo is intended to be parallel in structure to a companion document for Packet Loss ("A One-way Packet Loss Metric for IPPM") [2].

Although RFC 2119 was written with protocols in mind, the key words are used in this document for similar reasons. They are used to ensure the results of measurements from two different implementations are comparable, and to note instances when an implementation could perturb the network.

The structure of the memo is as follows:

+ A 'singleton' analytic metric, called Type-P-One-way-Delay, will be introduced to measure a single observation of one-way delay.

+ Using this singleton metric, a 'sample', called Type-P-One-way- Delay-Poisson-Stream, will be introduced to measure a sequence of singleton delays measured at times taken from a Poisson process.

+ Using this sample, several 'statistics' of the sample will be defined and discussed. This progression from singleton to sample to statistics, with clear 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

1.2. General Issues Regarding Time

2. A Singleton Definition for One-way Delay

2.1. Metric Name:

2.2. Metric Parameters:

2.3. Metric Units:

2.4. Definition:

2.5. Discussion:

2.6. Methodologies:

2.7. Errors and Uncertainties:

2.7.1. Errors or uncertainties related to Clocks

2.7.2. Errors or uncertainties related to Wire-time vs Host-time

2.7.3. Calibration

2.8. Reporting the metric:

2.8.1. Type-P

2.8.2. Loss Threshold

2.8.3. Calibration Results

2.8.4. Path

3. A Definition for Samples of One-way Delay

3.1. Metric Name:

3.2. Metric Parameters:

3.3. Metric Units:

3.4. Definition:

3.5. Discussion:

3.6. Methodologies:

3.7. Errors and Uncertainties:

3.8. Reporting the metric:

4. Some Statistics Definitions for One-way Delay

4.1. Type-P-One-way-Delay-Percentile

4.2. Type-P-One-way-Delay-Median

4.3. Type-P-One-way-Delay-Minimum

4.4. Type-P-One-way-Delay-Inverse-Percentile

5. Security Considerations

The

6. IANA Considerations

This memo makes no requests of IANA.

7. Acknowledgements

The authors thank

8. Refetrences (temporary)

[1] Paxson, V., Almes, G., Mahdavi, J. and M. Mathis, "Framework for IP Performance Metrics", RFC 2330, May 1998.

[2] Almes, G., Kalidindi, S. and M. Zekauskas, "A One-way Packet Loss Metric for IPPM", RFC 2680, September 1999.

[3] Mills, D., "Network Time Protocol (v3)", RFC 1305, April 1992.

[4] Mahdavi J. and V. Paxson, "IPPM Metrics for Measuring Connectivity", RFC 2678, September 1999.

[5] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1981.

[6] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.

[7] Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996.

9. References

9.1. Normative References

9.2. Informative References

Authors' Addresses