A Two-Way Active Measurement Protocol (TWAMP)
RFC 5357

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Network Working Group                                         K. Hedayat
Request for Comments: 5357                                 Brix Networks
Category: Standards Track                                  R. Krzanowski
                                                                 Verizon
                                                               A. Morton
                                                               AT&T Labs
                                                                  K. Yum
                                                        Juniper Networks
                                                              J. Babiarz
                                                         Nortel Networks
                                                            October 2008

             A Two-Way Active Measurement Protocol (TWAMP)

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.

Abstract

   The One-way Active Measurement Protocol (OWAMP), specified in RFC
   4656, provides a common protocol for measuring one-way metrics
   between network devices.  OWAMP can be used bi-directionally to
   measure one-way metrics in both directions between two network
   elements.  However, it does not accommodate round-trip or two-way
   measurements.  This memo specifies a Two-Way Active Measurement
   Protocol (TWAMP), based on the OWAMP, that adds two-way or round-trip
   measurement capabilities.  The TWAMP measurement architecture is
   usually comprised of two hosts with specific roles, and this allows
   for some protocol simplifications, making it an attractive
   alternative in some circumstances.

Hedayat, et al.             Standards Track                     [Page 1]
RFC 5357          Two-Way Active Measurement Protocol       October 2008

Table of Contents

   1. Introduction ....................................................2
      1.1. Relationship of Test and Control Protocols .................3
      1.2. Logical Model ..............................................3
      1.3. Pronunciation Guide ........................................4
   2. Protocol Overview ...............................................5
   3. TWAMP-Control ...................................................6
      3.1. Connection Setup ...........................................6
      3.2. Integrity Protection .......................................7
      3.3. Values of the Accept Field .................................7
      3.4. TWAMP-Control Commands .....................................7
      3.5. Creating Test Sessions .....................................8
      3.6. Send Schedules ............................................10
      3.7. Starting Test Sessions ....................................10
      3.8. Stop-Sessions .............................................10
      3.9. Fetch-Session .............................................12
   4. TWAMP-Test .....................................................12
      4.1. Sender Behavior ...........................................12
           4.1.1. Packet Timings .....................................12
           4.1.2. Packet Format and Content ..........................12
      4.2. Reflector Behavior ........................................13
           4.2.1. TWAMP-Test Packet Format and Content ...............14
   5. Implementers' Guide ............................................20
   6. Security Considerations ........................................20
   7. Acknowledgements ...............................................21
   8. IANA Considerations ............................................21
      8.1. Registry Specification ....................................22
      8.2. Registry Management .......................................22
      8.3. Experimental Numbers ......................................22
      8.4. Initial Registry Contents .................................22
   9. Internationalization Considerations ............................22
   Appendix I - TWAMP Light (Informative) ............................23
   Normative References ..............................................24
   Informative References ............................................24

1.  Introduction

   The Internet Engineering Task Force (IETF) has completed a Proposed
   Standard for the round-trip delay [RFC2681] metric.  The IETF has
   also completed a protocol for the control and collection of one-way
   measurements, the One-way Active Measurement Protocol (OWAMP)
   [RFC4656].  However, OWAMP does not accommodate round-trip or two-way
   measurements.

   Two-way measurements are common in IP networks, primarily because