Network Time Protocol Version 5
draft-mlichvar-ntp-ntpv5-01

Document Type Active Internet-Draft (individual)
Author Miroslav Lichvar 
Last updated 2020-12-09
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Internet Engineering Task Force                               M. Lichvar
Internet-Draft                                                   Red Hat
Intended status: Standards Track                             Dec 9, 2020
Expires: June 12, 2021

                    Network Time Protocol Version 5
                      draft-mlichvar-ntp-ntpv5-01

Abstract

   This document describes the version 5 of the Network Time Protocol
   (NTP).

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
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   This Internet-Draft will expire on June 12, 2021.

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   Copyright (c) 2020 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
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   described in the Simplified BSD License.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Basic Concepts  . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Data Types  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Message Format  . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Extension Fields  . . . . . . . . . . . . . . . . . . . . . .   8
     5.1.  Padding Extension Field . . . . . . . . . . . . . . . . .   9
     5.2.  MAC Extension Field . . . . . . . . . . . . . . . . . . .   9
     5.3.  Reference IDs Extension Field . . . . . . . . . . . . . .   9
     5.4.  Server Information Extension Field  . . . . . . . . . . .   9
     5.5.  Correction Extension Field  . . . . . . . . . . . . . . .  10
     5.6.  Reference Timestamp Extension Field . . . . . . . . . . .  10
     5.7.  Monotonic Timestamp Extension Field . . . . . . . . . . .  10
   6.  Client Operation  . . . . . . . . . . . . . . . . . . . . . .  11
   7.  Server Operation  . . . . . . . . . . . . . . . . . . . . . .  13
   8.  NTPv5 Negotiation in NTPv4  . . . . . . . . . . . . . . . . .  15
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  15
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  16
   11. Security Considerations . . . . . . . . . . . . . . . . . . .  16
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  16
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  16
     12.2.  Informative References . . . . . . . . . . . . . . . . .  16
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  16

1.  Introduction

   Network Time Protocol (NTP) is a protocol which enables computers to
   synchronize their clocks over network.  Time is distributed from
   primary time servers to clients, which can be servers for other
   clients, and so on.  Clients can use multiple servers simultaneously.

   NTPv5 is similar to NTPv4 [RFC5905].  The main differences are:

   1.   The protocol specification (this document) describes only the
        on-wire protocol.  Filtering of measurements, security
        mechanisms, source selection, clock control, and other
        algorithms, are out of scope.

   2.   NTPv5 drops support for the symmetric active, symmetric passive,
        broadcast, control, and private modes.  Only the client and
        server modes are supported.

   3.   Timestamps are clearly separated from values used as cookies.

   4.   NTPv5 messages can be extended only with extension fields.  The
        MAC field is wrapped in an extension field.

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   5.   Extension fields can be of any length, even indivisible by 4,
        but are padded to a multiple of 4 octets.  Extension fields
        specified for NTPv4 are compatible with NTPv5.
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