Internet Calendaring and Scheduling Core Object Specification (iCalendar)
RFC 2445

Document Type RFC - Proposed Standard (November 1998; Errata)
Obsoleted by RFC 5545
Last updated 2013-03-02
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Network Working Group                                         F. Dawson
Request for Comments: 2445                                        Lotus
Category: Standards Track                                  D. Stenerson
                                                              Microsoft
                                                          November 1998

     Internet Calendaring and Scheduling Core Object Specification
                              (iCalendar)

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 (1998).  All Rights Reserved.

Abstract

   There is a clear need to provide and deploy interoperable calendaring
   and scheduling services for the Internet. Current group scheduling
   and Personal Information Management (PIM) products are being extended
   for use across the Internet, today, in proprietary ways. This memo
   has been defined to provide the definition of a common format for
   openly exchanging calendaring and scheduling information across the
   Internet.

   This memo is formatted as a registration for a MIME media type per
   [RFC 2048]. However, the format in this memo is equally applicable
   for use outside of a MIME message content type.

   The proposed media type value is 'text/calendar'. This string would
   label a media type containing calendaring and scheduling information
   encoded as text characters formatted in a manner outlined below.

   This MIME media type provides a standard content type for capturing
   calendar event, to-do and journal entry information. It also can be
   used to convey free/busy time information. The content type is
   suitable as a MIME message entity that can be transferred over MIME
   based email systems, using HTTP or some other Internet transport. In

Dawson & Stenerson          Standards Track                     [Page 1]
RFC 2445                       iCalendar                   November 1998

   addition, the content type is useful as an object for interactions
   between desktop applications using the operating system clipboard,
   drag/drop or file systems capabilities.

   This memo is based on the earlier work of the vCalendar specification
   for the exchange of personal calendaring and scheduling information.
   In order to avoid confusion with this referenced work, this memo is
   to be known as the iCalendar specification.

   This memo defines the format for specifying iCalendar object methods.
   An iCalendar object method is a set of usage constraints for the
   iCalendar object. For example, these methods might define scheduling
   messages that request an event be scheduled, reply to an event
   request, send a cancellation notice for an event, modify or replace
   the definition of an event, provide a counter proposal for an
   original event request, delegate an event request to another
   individual, request free or busy time, reply to a free or busy time
   request, or provide similar scheduling messages for a to-do or
   journal entry calendar component. The iCalendar Transport-indendent
   Interoperability Protocol (iTIP) defined in [ITIP] is one such
   scheduling protocol.

Table of Contents

   1 Introduction.....................................................5
   2 Basic Grammar and Conventions....................................6
    2.1 Formatting Conventions .......................................7
    2.2 Related Memos ................................................8
    2.3 International Considerations .................................8
   3 Registration Information.........................................8
    3.1 Content Type .................................................8
    3.2 Parameters ...................................................9
    3.3 Content Header Fields .......................................10
    3.4 Encoding Considerations .....................................10
    3.5 Security Considerations .....................................10
    3.6 Interoperability Considerations .............................11
    3.7 Applications Which Use This Media Type ......................11
    3.8 Additional Information ......................................11
    3.9 Magic Numbers ...............................................11
    3.10 File Extensions ............................................11
    3.11 Contact for Further Information: ...........................12
    3.12 Intended Usage .............................................12
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