Guidelines for Defining Packet Timestamps
draft-ietf-ntp-packet-timestamps-07

Document Type Active Internet-Draft (ntp WG)
Last updated 2019-08-27 (latest revision 2019-08-20)
Replaces draft-mizrahi-intarea-packet-timestamps
Stream IETF
Intended RFC status Informational
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Document shepherd Karen O'Donoghue
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Send notices to Karen O'Donoghue <odonoghue@isoc.org>
NTP Working Group                                             T. Mizrahi
Internet-Draft                          Huawei Network.IO Innovation Lab
Intended status: Informational                                 J. Fabini
Expires: February 21, 2020                                       TU Wien
                                                               A. Morton
                                                               AT&T Labs
                                                         August 20, 2019

               Guidelines for Defining Packet Timestamps
                  draft-ietf-ntp-packet-timestamps-07

Abstract

   Various network protocols make use of binary-encoded timestamps that
   are incorporated in the protocol packet format, referred to as packet
   timestamps for short.  This document specifies guidelines for
   defining packet timestamp formats in networking protocols at various
   layers.  It also presents three recommended timestamp formats.  The
   target audience of this memo includes network protocol designers.  It
   is expected that a new network protocol that requires a packet
   timestamp will, in most cases, use one of the recommended timestamp
   formats.  If none of the recommended formats fits the protocol
   requirements, the new protocol specification should specify the
   format of the packet timestamp according to the guidelines in this
   document.

   The rationale behind defining a relatively small set of recommended
   formats is that it enables significant reuse; network protocols can
   typically reuse the timestamp format of the Network Time Protocol
   (NTP) or the Precision Time Protocol (PTP), allowing a
   straightforward integration with an NTP or a PTP-based timer.
   Moreover, since accurate timestamping mechanisms are often
   implemented in hardware, a new network protocol that reuses an
   existing timestamp format can be quickly deployed using existing
   hardware timestamping capabilities.

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

Mizrahi, et al.         Expires February 21, 2020               [Page 1]
Internet-Draft              Packet Timestamps                August 2019

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 21, 2020.

Copyright Notice

   Copyright (c) 2019 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
   (https://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.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     2.2.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   3
     2.3.  Terms used in this Document . . . . . . . . . . . . . . .   4
   3.  Packet Timestamp Specification Template . . . . . . . . . . .   4
   4.  Recommended Timestamp Formats . . . . . . . . . . . . . . . .   5
     4.1.  Using a Recommended Timestamp Format  . . . . . . . . . .   6
     4.2.  NTP Timestamp Formats . . . . . . . . . . . . . . . . . .   6
       4.2.1.  NTP 64-bit Timestamp Format . . . . . . . . . . . . .   6
       4.2.2.  NTP 32-bit Timestamp Format . . . . . . . . . . . . .   8
     4.3.  The PTP Truncated Timestamp Format  . . . . . . . . . . .   9
   5.  Synchronization Aspects . . . . . . . . . . . . . . . . . . .  11
   6.  Timestamp Use Cases . . . . . . . . . . . . . . . . . . . . .  12
     6.1.  Example 1 . . . . . . . . . . . . . . . . . . . . . . . .  13
     6.2.  Example 2 . . . . . . . . . . . . . . . . . . . . . . . .  13
   7.  Packet Timestamp Control Field  . . . . . . . . . . . . . . .  13
     7.1.  High-level Control Field Requirements . . . . . . . . . .  14
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  15
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  15
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