Date and Time on the Internet: Timestamps
RFC 3339
Document | Type | RFC - Proposed Standard (July 2002; Errata) | |
---|---|---|---|
Authors | Chris Newman , Graham Klyne | ||
Last updated | 2020-01-21 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized with errata bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 3339 (Proposed Standard) | |
Action Holders |
(None)
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||
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Ned Freed | ||
IESG note | Responsible: Finished | ||
Send notices to | (None) |
Network Working Group G. Klyne Request for Comments: 3339 Clearswift Corporation Category: Standards Track C. Newman Sun Microsystems July 2002 Date and Time on the Internet: Timestamps Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2002). All Rights Reserved. Abstract This document defines a date and time format for use in Internet protocols that is a profile of the ISO 8601 standard for representation of dates and times using the Gregorian calendar. 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 ............................. 8 5.7. Restrictions .......................................... 9 5.8. Examples ............................................. 10 6. References ............................................. 10 7. Security Considerations ................................ 11 Klyne, et. al. Standards Track [Page 1] RFC 3339 Date and Time on the Internet: Timestamps July 2002 Appendix A. ISO 8601 Collected ABNF ....................... 12 Appendix B. Day of the Week ............................... 14 Appendix C. Leap Years .................................... 14 Appendix D. Leap Seconds ..............................,... 15 Acknowledgements .......................................... 17 Authors' Addresses ........................................ 17 Full Copyright Statement .................................. 18 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 Internet profile of the ISO 8601 [ISO8601] standard for representation of dates and times using the Gregorian calendar. There are many ways in which date and time values might appear in Internet protocols: this document focuses on just one common usage, viz. timestamps for Internet protocol events. This limited consideration has the following consequences: o All dates and times are assumed to be in the "current era", somewhere between 0000AD and 9999AD. o All times expressed have a stated relationship (offset) to Coordinated Universal Time (UTC). (This is distinct from some usage in scheduling applications where a local time and location may be known, but the actual relationship to UTC may be dependent on the unknown or unknowable actions of politicians or administrators. The UTC time corresponding to 17:00 on 23rd March 2005 in New York may depend on administrative decisions about daylight savings time. This specification steers well clear of such considerations.) o Timestamps can express times that occurred before the introduction of UTC. Such timestamps are expressed relative to universal time, using the best available practice at the stated time. o Date and time expressions indicate an instant in time. Description of time periods, or intervals, is not covered here. Klyne, et. al. Standards Track [Page 2] RFC 3339 Date and Time on the Internet: Timestamps July 2002 2. Definitions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in thisShow full document text