The Time Zone Information Format (TZif)
draft-murchison-tzdist-tzif-05

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Last updated 2018-06-05
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Independent Submission                                          A. Olson
Internet-Draft
Updates: 7808 (if approved)                                    P. Eggert
Intended status: Standards Track                                    UCLA
Expires: December 7, 2018                                   K. Murchison
                                                                FastMail
                                                            June 5, 2018

                The Time Zone Information Format (TZif)
                     draft-murchison-tzdist-tzif-05

Abstract

   This document defines the Time Zone Information Format (TZif) for
   representing and exchanging time zone information, independent of any
   particular service or protocol.  A MIME media type for this format is
   also defined.

Open Issues

   o  Should we require TZDIST servers to always return a particular
      format (2 or 3) with/without leap seconds?  Or should we allow the
      client to choose what they want (via parameters on the MIME type)?
      E.g. application/tzif+leap; version=3

   o  Is the MIME registration complete and correct (e.g. any security
      or privacy considerations)?

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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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 7, 2018.

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Copyright Notice

   Copyright (c) 2018 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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   3
   3.  The Time Zone Information Format (TZif) . . . . . . . . . . .   4
     3.1.  TZif Header . . . . . . . . . . . . . . . . . . . . . . .   5
     3.2.  TZif Data Block . . . . . . . . . . . . . . . . . . . . .   7
     3.3.  TZif Footer . . . . . . . . . . . . . . . . . . . . . . .  10
       3.3.1.  TZ String Extensions  . . . . . . . . . . . . . . . .  11
   4.  Use with the Time Zone Data Distribution Service  . . . . . .  11
     4.1.  Example . . . . . . . . . . . . . . . . . . . . . . . . .  11
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   6.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .  13
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  14
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  14
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  15
     9.3.  URIs  . . . . . . . . . . . . . . . . . . . . . . . . . .  15
   Appendix A.  Change History (To be removed by RFC Editor before
                publication) . . . . . . . . . . . . . . . . . . . .  15
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  17

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 defines the Time Zone Information Format.  It is a
   binary format used by most UNIX systems to calculate local time.
   There is a wide variety of interoperable software [tz-link] capable
   of generating and reading files in this format.

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   This specification does not define the source of the time zone data
   or leap second information.  One such source is the IANA-hosted time
   zone database [RFC6557].

2.  Conventions Used in This Document
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