The Time Zone Information Format (TZif)
draft-murchison-rfc8536bis-00

Document Type Active Internet-Draft (individual)
Authors Arthur Olson  , Paul Eggert  , Kenneth Murchison 
Last updated 2021-03-08
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Internet Engineering Task Force (IETF)                          A. Olson
Internet-Draft
Obsoletes: 8536 (if approved)                                  P. Eggert
Intended status: Standards Track                                    UCLA
Expires: September 9, 2021                                  K. Murchison
                                                                Fastmail
                                                           March 8, 2021

                The Time Zone Information Format (TZif)
                     draft-murchison-rfc8536bis-00

Abstract

   This document specifies the Time Zone Information Format (TZif) for
   representing and exchanging time zone information, independent of any
   particular service or protocol.  Two media types for this format are
   also defined.

   This document replaces and obsoletes RFC 8536.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on September 9, 2021.

Copyright Notice

   Copyright (c) 2021 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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   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents

Olson, et al.           Expires September 9, 2021               [Page 1]
Internet-Draft                    TZif                        March 2021

   carefully, as they describe your rights and restrictions with respect
   to this document.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   3
   3.  The Time Zone Information Format (TZif) . . . . . . . . . . .   5
     3.1.  TZif Header . . . . . . . . . . . . . . . . . . . . . . .   6
     3.2.  TZif Data Block . . . . . . . . . . . . . . . . . . . . .   8
     3.3.  TZif Footer . . . . . . . . . . . . . . . . . . . . . . .  11
       3.3.1.  TZ String Extensions  . . . . . . . . . . . . . . . .  12
   4.  Interoperability Considerations . . . . . . . . . . . . . . .  13
   5.  Use with the Time Zone Data Distribution Service  . . . . . .  14
     5.1.  Truncating TZif Files . . . . . . . . . . . . . . . . . .  14
     5.2.  Example TZDIST Request for TZif Data  . . . . . . . . . .  15
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  17
   7.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .  17
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  17
     8.1.  application/tzif  . . . . . . . . . . . . . . . . . . . .  17
     8.2.  application/tzif-leap . . . . . . . . . . . . . . . . . .  18
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  19
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  20
   Appendix A.  Common Interoperability Issues . . . . . . . . . . .  21
   Appendix B.  Example TZif Files . . . . . . . . . . . . . . . . .  23
     B.1.  Version 1 File Representing UTC (with Leap Seconds) . . .  23
     B.2.  Version 2 File Representing Pacific/Honolulu  . . . . . .  27
     B.3.  Truncated Version 3 File Representing Asia/Jerusalem  . .  32
   Appendix C.  Changes from RFC 8536  . . . . . . . . . . . . . . .  34
   Appendix D.  Change Log . . . . . . . . . . . . . . . . . . . . .  34
     D.1.  Since RFC 8536  . . . . . . . . . . . . . . . . . . . . .  34
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  35
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  35

1.  Introduction

   Time zone data typically consists of offsets from universal time
   (UT), daylight saving transition rules, one or more local time
   designations (acronyms or abbreviations), and optional leap-second
   adjustments.  One such format for conveying this information is
   iCalendar [RFC5545].  It is a text-based format used by calendaring
   and scheduling systems.

   This document specifies the widely deployed Time Zone Information
   Format (TZif).  It is a binary format used by most UNIX systems to
   calculate local time.  This format was introduced in the 1980s and
   has evolved since then into multiple upward-compatible versions.
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