RFC 2330 (rfc2330) - Page 2 of 40

Framework for IP Performance Metrics

RFC 2330          Framework for IP Performance Metrics          May 1998


     11.2  Self-Consistency...........................................24
     11.3  Defining Statistical Distributions.........................25
     11.4  Testing For Goodness-of-Fit................................27
   12. AVOIDING STOCHASTIC METRICS....................................28
   13. PACKETS OF TYPE P..............................................29
   14. INTERNET ADDRESSES VS. HOSTS...................................30
   15. STANDARD-FORMED PACKETS........................................30
   16. ACKNOWLEDGEMENTS...............................................31
   17. SECURITY CONSIDERATIONS........................................31
   18. APPENDIX.......................................................32
   19. REFERENCES.....................................................38
   20. AUTHORS' ADDRESSES.............................................39
   21. FULL COPYRIGHT STATEMENT.......................................40


3. Introduction

   The purpose of this memo is to define a general framework for
   particular metrics to be developed by the IETF's IP Performance
   Metrics effort, begun by the Benchmarking Methodology Working Group
   (BMWG) of the Operational Requirements Area, and being continued by
   the IP Performance Metrics Working Group (IPPM) of the Transport
   Area.

   We begin by laying out several criteria for the metrics that we
   adopt.  These criteria are designed to promote an IPPM effort that
   will maximize an accurate common understanding by Internet users and
   Internet providers of the performance and reliability both of end-
   to-end paths through the Internet and of specific 'IP clouds' that
   comprise portions of those paths.

   We next define some Internet vocabulary that will allow us to speak
   clearly about Internet components such as routers, paths, and clouds.

   We then define the fundamental concepts of 'metric' and 'measurement
   methodology', which allow us to speak clearly about measurement
   issues.  Given these concepts, we proceed to discuss the important
   issue of measurement uncertainties and errors, and develop a key,
   somewhat subtle notion of how they relate to the analytical framework
   shared by many aspects of the Internet engineering discipline.  We
   then introduce the notion of empirically defined metrics, and finish
   this part of the document with a general discussion of how metrics
   can be 'composed'.

   The remainder of the document deals with a variety of issues related
   to defining sound metrics and methodologies:  how to deal with
   imperfect clocks; the notion of 'wire time' as distinct from 'host
   time'; how to aggregate sets of singleton metrics into samples and



Paxson, et. al.              Informational