Network Working Group G. Almes Internet-Draft S. Kalidindi Intended status: Informational M. Zekauskas Expires: April 18, 2013 A. Morton, Ed. AT&T Labs October 15, 2012 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/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 18, 2013. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Almes, et al. Expires April 18, 2013 [Page 1] Internet-Draft A One-Way Delay Metric for IPPM October 2012 Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Almes, et al. Expires April 18, 2013 [Page 2] Internet-Draft A One-Way Delay Metric for IPPM October 2012 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. General Issues Regarding Time . . . . . . . . . . . . . . . 4 2. A Singleton Definition for One-way Delay . . . . . . . . . . . 4 2.1. Metric Name: . . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Metric Parameters: . . . . . . . . . . . . . . . . . . . . 4 2.3. Metric Units: . . . . . . . . . . . . . . . . . . . . . . . 5 2.4. Definition: . . . . . . . . . . . . . . . . . . . . . . . . 5 2.5. Discussion: . . . . . . . . . . . . . . . . . . . . . . . . 5 2.6. Methodologies: . . . . . . . . . . . . . . . . . . . . . . 5 2.7. Errors and Uncertainties: . . . . . . . . . . . . . . . . . 5 2.7.1. Errors or uncertainties related to Clocks . . . . . . . 5 2.7.2. Errors or uncertainties related to Wire-time vs Host-time . . . . . . . . . . . . . . . . . . . . . . . 5 2.7.3. Calibration . . . . . . . . . . . . . . . . . . . . . . 5 2.8. Reporting the metric: . . . . . . . . . . . . . . . . . . . 5 2.8.1. Type-P . . . . . . . . . . . . . . . . . . . . . . . . 5 2.8.2. Loss Threshold . . . . . . . . . . . . . . . . . . . . 5 2.8.3. Calibration Results . . . . . . . . . . . . . . . . . . 5 2.8.4. Path . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. A Definition for Samples of One-way Delay . . . . . . . . . . . 5 3.1. Metric Name: . . . . . . . . . . . . . . . . . . . . . . . 5 3.2. Metric Parameters: . . . . . . . . . . . . . . . . . . . . 5 3.3. Metric Units: . . . . . . . . . . . . . . . . . . . . . . . 5 3.4. Definition: . . . . . . . . . . . . . . . . . . . . . . . . 5 3.5. Discussion: . . . . . . . . . . . . . . . . . . . . . . . . 5 3.6. Methodologies: . . . . . . . . . . . . . . . . . . . . . . 5 3.7. Errors and Uncertainties: . . . . . . . . . . . . . . . . . 5 3.8. Reporting the metric: . . . . . . . . . . . . . . . . . . . 5 4. Some Statistics Definitions for One-way Delay . . . . . . . . . 6 4.1. Type-P-One-way-Delay-Percentile . . . . . . . . . . . . . . 6 4.2. Type-P-One-way-Delay-Median . . . . . . . . . . . . . . . . 6 4.3. Type-P-One-way-Delay-Minimum . . . . . . . . . . . . . . . 6 4.4. Type-P-One-way-Delay-Inverse-Percentile . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 8. Refetrences (temporary) . . . . . . . . . . . . . . . . . . . . 6 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 9.1. Normative References . . . . . . . . . . . . . . . . . . . 7 9.2. Informative References . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Almes, et al. Expires April 18, 2013 [Page 3] Internet-Draft A One-Way Delay Metric for IPPM October 2012 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: Almes, et al. Expires April 18, 2013 [Page 4] Internet-Draft A One-Way Delay Metric for IPPM October 2012 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: Almes, et al. Expires April 18, 2013 [Page 5] Internet-Draft A One-Way Delay Metric for IPPM October 2012 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. Almes, et al. Expires April 18, 2013 [Page 6] Internet-Draft A One-Way Delay Metric for IPPM October 2012 9. References 9.1. Normative References [RFC2026] Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996. [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 One-way Delay Metric for IPPM", RFC 2679, September 1999. [RFC2680] Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way Packet Loss Metric for IPPM", RFC 2680, September 1999. [RFC3432] Raisanen, V., Grotefeld, G., and A. Morton, "Network performance measurement with periodic streams", RFC 3432, November 2002. [RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M. Zekauskas, "A One-way Active Measurement Protocol (OWAMP)", RFC 4656, September 2006. [RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J. Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)", RFC 5357, October 2008. [RFC5657] Dusseault, L. and R. Sparks, "Guidance on Interoperation and Implementation Reports for Advancement to Draft Standard", BCP 9, RFC 5657, September 2009. [RFC5835] Morton, A. and S. Van den Berghe, "Framework for Metric Composition", RFC 5835, April 2010. [RFC6049] Morton, A. and E. Stephan, "Spatial Composition of Metrics", RFC 6049, January 2011. [RFC6576] Geib, R., Morton, A., Fardid, R., and A. Steinmitz, "IP Performance Metrics (IPPM) Standard Advancement Testing", BCP 176, RFC 6576, March 2012. [RFC6703] Morton, A., Ramachandran, G., and G. Maguluri, "Reporting IP Network Performance Metrics: Different Points of View", Almes, et al. Expires April 18, 2013 [Page 7] Internet-Draft A One-Way Delay Metric for IPPM October 2012 RFC 6703, August 2012. 9.2. Informative References [ADK] Scholz, F. and M. Stephens, "K-sample Anderson-Darling Tests of fit, for continuous and discrete cases", University of Washington, Technical Report No. 81, May 1986. [RFC3931] Lau, J., Townsley, M., and I. Goyret, "Layer Two Tunneling Protocol - Version 3 (L2TPv3)", RFC 3931, March 2005. Authors' Addresses Guy Almes Phone: Fax: Email: URI: S. Kalidindi Phone: Fax: Email: URI: Matt Zekauskas Phone: Fax: Email: URI: Almes, et al. Expires April 18, 2013 [Page 8] Internet-Draft A One-Way Delay Metric for IPPM October 2012 Al Morton AT&T Labs 200 Laurel Avenue South Middletown, NJ 07748 USA Phone: +1 732 420 1571 Fax: +1 732 368 1192 Email: acmorton@att.com URI: http://home.comcast.net/~acmacm/ Almes, et al. Expires April 18, 2013 [Page 9]