Date and Time on the Internet: Timestamps with additional information
draft-ryzokuken-datetime-extended-00

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Calendaring Extensions Working Group                           U. Sharma
Internet-Draft                                              Igalia, S.L.
Obsoletes: 3339 (if approved)                            11 January 2021
Intended status: Standards Track                                        
Expires: 15 July 2021

 Date and Time on the Internet: Timestamps with additional information
                  draft-ryzokuken-datetime-extended-00

Abstract

   This document defines a date and time format for use in Internet
   protocols for representation of dates and times using the proleptic
   Gregorian calendar, with optional extensions representing additional
   information including a time zone and a calendaring system.

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Sharma                    Expires 15 July 2021                  [Page 1]
Internet-Draft             Timestamps Extended              January 2021

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Two Digit Years . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Local Time  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Coordinated Universal Time (UTC)  . . . . . . . . . . . .   4
     4.2.  Local Offsets . . . . . . . . . . . . . . . . . . . . . .   5
     4.3.  Unknown Local Offset Convention . . . . . . . . . . . . .   5
     4.4.  Unqualified Local Time  . . . . . . . . . . . . . . . . .   5
   5.  Date and Time format  . . . . . . . . . . . . . . . . . . . .   6
     5.1.  Ordering  . . . . . . . . . . . . . . . . . . . . . . . .   6
     5.2.  Human Readability . . . . . . . . . . . . . . . . . . . .   6
     5.3.  Rarely Used Options . . . . . . . . . . . . . . . . . . .   7
     5.4.  Redundant Information . . . . . . . . . . . . . . . . . .   7
     5.5.  Simplicity  . . . . . . . . . . . . . . . . . . . . . . .   7
     5.6.  Internet Date/Time Format . . . . . . . . . . . . . . . .   7
     5.7.  Restrictions  . . . . . . . . . . . . . . . . . . . . . .   9
     5.8.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .  10
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   7.  Normative references  . . . . . . . . . . . . . . . . . . . .  12
   8.  Bibliography  . . . . . . . . . . . . . . . . . . . . . . . .  12
   Appendix A.  Day of the Week  . . . . . . . . . . . . . . . . . .  13
   Appendix B.  Leap Years . . . . . . . . . . . . . . . . . . . . .  13
   Appendix C.  Leap Seconds . . . . . . . . . . . . . . . . . . . .  13
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   Date and time formats cause a lot of confusion and interoperability
   problems on the Internet.  This document addresses many of the
   problems encountered and makes recommendations to improve consistency
   and interoperability when representing and using date and time in
   Internet protocols.

   This document includes an extension to an Internet profile of the
   [ISO8601] standard for representation of dates and times using the
   proleptic Gregorian calendar alongside any additional information.
   Any dates and times that are required to be handled in a different
   calendar system need to include the ID of the calendar which can be
   handle by the implementations approximately.  In the absence of a
   calendar ID, the proleptic Gregorian calendar system is assumed.

   There are many ways in which date and time values might appear in
   Internet protocols: this document focuses on just one common usage,