IP Packet Delay Variation Metric for IP Performance Metrics (IPPM)
RFC 3393

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Network Working Group                                      C. Demichelis
Request for Comments: 3393                             Telecomitalia Lab
Category: Standards Track                                    P. Chimento
                                                            Ericsson IPI
                                                           November 2002

                    IP Packet Delay Variation Metric
                   for IP Performance Metrics (IPPM)

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document refers to a metric for variation in delay of packets
   across Internet paths.  The metric is based on the difference in the
   One-Way-Delay of selected packets.  This difference in delay is
   called "IP Packet Delay Variation (ipdv)".

   The metric is valid for measurements between two hosts both in the
   case that they have synchronized clocks and in the case that they are
   not synchronized.  We discuss both in this document.

Table of Contents

   1 Introduction..................................................... 2
     1.1 Terminology.................................................. 3
     1.2 Definition................................................... 3
     1.3 Motivation................................................... 4
     1.4 General Issues Regarding Time................................ 5
   2 A singleton definition of a One-way-ipdv metric.................. 5
     2.1 Metric name.................................................. 6
     2.2 Metric parameters............................................ 6
     2.3 Metric unit.................................................. 6
     2.4 Definition................................................... 6
     2.5 Discussion................................................... 7
     2.6 Methodologies................................................ 9
     2.7 Errors and Uncertainties.....................................10

Demichelis & Chimento       Standards Track                     [Page 1]
RFC 3393               IP Packet Delay Variation           November 2002

         2.7.1 Errors/Uncertainties related to Clocks.................11
         2.7.2 Errors/uncertainties related to Wire-time vs Host-time.12
   3 Definitions for Samples of One-way-ipdv..........................12
     3.1 Metric name..................................................12
     3.2 Parameters...................................................12
     3.3 Metric Units.................................................13
     3.4 Definition...................................................13
     3.5 Discussion...................................................13
     3.6 Methodology..................................................14
     3.7 Errors and uncertainties.....................................14
   4 Statistics for One-way-ipdv......................................14
     4.1 Lost Packets and ipdv statistics.............................15
     4.2 Distribution of One-way-ipdv values..........................15
     4.3 Type-P-One-way-ipdv-percentile...............................16
     4.4 Type-P-One-way-ipdv-inverse-percentile.......................16
     4.5 Type-P-One-way-ipdv-jitter...................................16
     4.6 Type-P-One-way-peak-to-peak-ipdv.............................16
   5 Discussion of clock synchronization..............................17
     5.1 Effects of synchronization errors............................17
     5.2 Estimating the skew of unsynchronized clocks.................18
   6 Security Considerations..........................................18
     6.1 Denial of service............................................18
     6.2 Privacy/Confidentiality......................................18
     6.3 Integrity....................................................19
   7 Acknowledgments..................................................19
   8 References.......................................................19
      8.1 Normative References........................................19
      8.2 Informational References....................................19
   9 Authors' Addresses...............................................20
   10 Full Copyright Statement........................................21

1. Introduction

   This memo defines a metric for the variation in delay of packets that
   flow from one host to another through an IP path.  It is based on "A
   One-Way-Delay metric for IPPM", RFC 2679 [2] and part of the text in
   this memo is taken directly from that document; the reader is assumed