Multipath Time Synchronization
RFC 8039

Document Type RFC - Experimental (December 2016; No errata)
Last updated 2016-12-08
Replaces draft-shpiner-multi-path-synchronization
Stream IETF
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Stream WG state Submitted to IESG for Publication Jun 2016
Document shepherd Karen O'Donoghue
Shepherd write-up Show (last changed 2016-07-20)
IESG IESG state RFC 8039 (Experimental)
Consensus Boilerplate Yes
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Responsible AD Suresh Krishnan
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IANA IANA review state Version Changed - Review Needed
IANA action state No IC
Internet Engineering Task Force (IETF)                        A. Shpiner
Request for Comments: 8039                                      Mellanox
Category: Experimental                                            R. Tse
ISSN: 2070-1721                                                Microsemi
                                                               C. Schelp
                                                                  Oracle
                                                              T. Mizrahi
                                                                 Marvell
                                                           December 2016

                     Multipath Time Synchronization

Abstract

   Clock synchronization protocols are very widely used in IP-based
   networks.  The Network Time Protocol (NTP) has been commonly deployed
   for many years, and the last few years have seen an increasingly
   rapid deployment of the Precision Time Protocol (PTP).  As time-
   sensitive applications evolve, clock accuracy requirements are
   becoming increasingly stringent, requiring the time synchronization
   protocols to provide high accuracy.  This memo describes a multipath
   approach to PTP and NTP over IP networks, allowing the protocols to
   run concurrently over multiple communication paths between the master
   and slave clocks, without modifying these protocols.  The multipath
   approach can significantly contribute to clock accuracy, security,
   and fault tolerance.  The multipath approach that is presented in
   this document enables backward compatibility with nodes that do not
   support the multipath functionality.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for examination, experimental implementation, and
   evaluation.

   This document defines an Experimental Protocol for the Internet
   community.  This document is a product of the Internet Engineering
   Task Force (IETF).  It represents the consensus of the IETF
   community.  It has received public review and has been approved for
   publication by the Internet Engineering Steering Group (IESG).  Not
   all documents approved by the IESG are a candidate for any level of
   Internet Standard; see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc8039.

Shpiner, et al.               Experimental                      [Page 1]
RFC 8039             Multipath Time Synchronization        December 2016

Copyright Notice

   Copyright (c) 2016 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
   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.

Table of Contents

   1. Introduction ....................................................3
   2. Conventions Used in This Document ...............................4
      2.1. Abbreviations ..............................................4
      2.2. Terminology ................................................4
   3. Multiple Paths in IP Networks ...................................5
      3.1. Load Balancing .............................................5
      3.2. Using Multiple Paths Concurrently ..........................5
      3.3. Two-Way Paths ..............................................5
   4. Solution Overview ...............................................6
      4.1. Path Configuration and Identification ......................6
      4.2. Combining ..................................................6
   5. Multipath Time Synchronization over IP Networks .................7
      5.1. Overview ...................................................7
      5.2. Single-Ended Multipath Synchronization .....................8
           5.2.1. Single-Ended MPPTP Synchronization Message
                  Exchange ............................................8
           5.2.2. Single-Ended MPNTP Synchronization Message
                  Exchange ............................................9
      5.3. Dual-Ended Multipath Synchronization ......................10
           5.3.1. Dual-Ended MPPTP Synchronization Message Exchange ..10
           5.3.2. Dual-Ended MPNTP Synchronization Message Exchange ..11
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