Network Working Group                                            T. Small
Request for Comments: 2739                                  XpertSite.Com
Category: Standards Track                                     D. Hennessy
                                                                  ISOCOR
                                                               F. Dawson
                                                                   Lotus
                                                            January 2000


                Calendar Attributes for vCard and LDAP


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 (2000).  All Rights Reserved.

Abstract

  When scheduling a calendar entity, such as an event, it is a
  prerequisite that an organizer has the calendar address of each
  attendee that will be invited to the event. Additionally, access to
  an attendee's current "busy time" provides an a priori indication of
  whether the attendee will be free to participate in the event.

  In order to meet these challenges, a calendar user agent (CUA) needs
  a mechanism to locate (URI) individual user's calendar and free/busy
  time.

  This memo defines three mechanisms for obtaining a URI to a user's
  calendar and free/busy time. These include:

  - Manual transfer of the information;

  - Personal data exchange using the vCard format; and

  - Directory lookup using the LDAP protocol.







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Table of Contents

  1 CALENDARING AND SCHEDULING URIS...................................3
   1.1 FREE/BUSY URI (FBURL) .........................................3
   1.2 CALENDAR ACCESS URI (CAPURI) ..................................4
   1.3 CALENDAR URI (CALURI) .........................................4
   1.4 DEFAULT URIS ..................................................4
  2 DISTRIBUTION......................................................4
   2.1 MANUAL TRANSFER ...............................................5
   2.2 PERSONAL DATA EXCHANGE USING A VCARD ..........................5
   2.3 VCARD SCHEMA EXTENSIONS .......................................5
    2.3.1 FBURL Property IANA Registration ...........................6
    2.3.2 CALADRURI Property IANA Registration .......................7
    2.3.3 CAPURI Property IANA Registration ......................... 8
    2.3.4 CALURI Property IANA Registration ......................... 8
   2.4 DIRECTORY LOOKUP USING THE LDAP V3 PROTOCOL .................. 9
    2.4.1 LDAP Schema Extensions .................................... 9
    2.4.2 Notation ..................................................10
    2.4.3 Object Definitions ........................................10
      2.4.3.1 calEntry ..............................................10
    2.4.4 Attribute Definitions .....................................10
      2.4.4.1 calCalURI .............................................10
      2.4.4.2 calFBURL ..............................................10
      2.4.4.3 calCAPURI .............................................11
      2.4.4.4 calCalAdrURI ..........................................11
      2.4.4.5 calOtherCalURIs .......................................11
      2.4.4.6 calOtherFBURLs ........................................11
      2.4.4.7 calOtherCAPURIs .......................................12
      2.4.4.8 calOtherCalAdrURIs ....................................12
  3 IANA Considerations..............................................12
  4 Security Considerations..........................................12
  5 Acknowledgments..................................................13
  6 Authors' Addresses...............................................13
  7 Bibliography.....................................................15
  8 Full Copyright Statement.........................................16
















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1  Calendaring and Scheduling URIs

  This memo defines four classes of URIs. URIs are more useful if it is
  understood what the URIs point to. Here is a brief description:

1.1 Free/Busy URI (FBURL)

  The free/busy URI is defined to be a transport independent location
  where a client can obtain information about when a user is busy. At
  the present time, this URI only points to busy time data. Future
  revisions of this specification may provide for the extended
  capability of publishing free time data.

  If a calendaring and scheduling client (i.e., CUA) were to retrieve
  data from this location using FTP or HTTP, it would get back an
  iCalendar object [4] containing one or more "VFREEBUSY" calendar
  components. If a MIME transport is being used, the response will be
  contained within a "text/calendar" MIME body part as specified in the
  iCalendar specification [4]. For example:

     BEGIN:VCALENDAR
     VERSION:2.0
     PRODID:-//hacksw/handcal//NONSGML v1.0//EN
     METHOD:PUBLISH
     BEGIN:VFREEBUSY
     ATTENDEE:MAILTO:[email protected]
     DTSTART:19971013T050000Z
     DTEND:19971124T050000Z
     DTSTAMP:19970901T083000Z
     FREEBUSY:19971015T133000Z/19971015T180000Z
     FREEBUSY:19971015T190000Z/19971015T220000Z
     FBURL:http://www.host.com/calendar/busy/jdoe.ifb
     END:VFREEBUSY
     END:VCALENDAR

  The amount of busy time data pointed to by the FBURL will generally
  be pre-determined; for example one month of busy time data. As a
  guideline, it is recommended that the previous six weeks of busy time
  data be published at the location associated with the FBURL. If this
  URI points to a file resource, it is recommended that the file
  extension be "ifb" to distinguish it from an arbitrary iCalendar
  object (e.g., with the "ics" file extension).









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1.2 Calendar Access URI (CAPURI)

  The Calendar Access URI is defined to be a protocol independent
  location from which a calendaring and scheduling client (i.e., CUA)
  can communicate with a user's entire calendar.

  The semantics for using this URI as an access protocol locator are
  yet to be defined by the IETF CALSCH Working Group. This will be
  addressed in the "Calendar Access Protocol" specification.

1.3 Calendar URI (CALURI)

  The Calendar URI is defined to be a protocol independent location
  from which a calendaring and scheduling client (i.e. CUA) can
  retrieve an entire copy of a user's calendar. Retrieving data from
  this URI obtains a published "snapshot" of the user's calendar.

  HTTP URI -- If the URI is an HTTP URI, then the content returned with
  a GET should be a "text/calendar" MIME body part containing one or
  more iCalendar object.

  FTP URI -- If the URI is an FTP URI, then the resource pointed to
  should be a file with an "ics" file extension containing one or more
  iCalendar objects.

1.4 Default URIs

  There are many cases where a user may have more than one calendar. In
  these cases, a user may have multiple URIs, each URI pointing to a
  calendar or free/busy data.

  To make the case of multiple calendars simpler for clients, the
  concept of the "default" calendar is introduced. A "default" calendar
  is one that the user has designated as the calendar that other users
  should look at when accessing the user's calendar, or retrieving the
  user's free/busy time.

  The default calendar may, in fact, include rolled-up information from
  all the user's other calendars. The other calendars may only exist
  for organizational purposes.

2  Distribution

  These four URIs provide valuable pointers to calendaring and
  scheduling data that other users need in order to know when to
  schedule meetings, etc. There are several possibilities on how users
  can communicate these URIs to other users. The following section
  outlines how these URIs can be distributed to other users.



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2.1 Manual Transfer

  The simplest way to obtain these URIs is for a user to communicate
  the URIs using some out-of-band mechanism such as verbally, or in an
  e-mail message, or by printing these URIs on a paper business card.

  When using this mechanism, the user obtains these URIs using an out-
  of-band mechanism and then enters these URIs into their calendaring
  software manually.

2.2 Personal Data Exchange Using A vCard

  A more sophisticated way to obtain these URIs is for users to publish
  vCards containing these URIs. The vCard object can be transferred
  between one another. Since many e-mail clients allow a user to
  automatically include a vCard with every message that the user sends,
  this provides a simple, transparent way for a user to distribute
  their calendaring and scheduling URIs.

  On the receiving end, an e-mail client that provides an integrated
  vCard database can provide a way to lookup calendaring URIs for users
  whose vCards are stored locally.

2.3 vCard Schema Extensions

  Since the vCard [3] specification doesn't specify how to encode
  calendaring URIs in a vCard, this section is provided as an extension
  to vCard which specifies how to encode calendaring URIs within a
  vCard.

  Inside a vCard object, four new properties are defined: "CALURI",
  "CAPURI", "CALADRURI", and "FBURL", as defined above.

  Any vCard can have one or more of these properties, each representing
  a calendar or free/busy time that is associated with the user.

  One of these properties can be designated as the "default" by adding
  the "PREF" parameter.













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  Here is a simple example of a vCard containing a "FBURL" and a
  "CALURI".

     BEGIN:VCARD
     VERSION:3.0
     N:Dun;Alec
     FN:Alec Dun
     ORG:Microsoft Corporation
     ADR;WORK;POSTAL;PARCEL:;;One Microsoft Way;
      Redmond;WA;98052-6399;USA
     TEL;WORK;MSG:+1-206-936-4544
     TEL;WORK;FAX:+1-206-936-7329
     EMAIL;INTERNET:[email protected]
     CALADRURI;PREF:mailto:[email protected]
     CALURI;PREF:http://cal.host1.com/user/cal.ics
     FBURL;PREF:http://cal.host1.com/user/fb.ifb
     CALURI:http://cal.company.com/projectA/pjtA.ics
     FBURL:http://cal.company.com/projectA/pjtAfb.ifb
     END:VCARD

2.3.1 FBURL Property IANA Registration

  To: [email protected]

  Subject: Registration of FBURL type for text/directory MIME type
  vCard profile.

  Type name: FBURL

  Type purpose: To specify the URI for a user's busy time in a vCard
  object.

  Type encoding: 8bit

  Type value: A single URI value.

  Type special notes: Where multiple FBURL properties are specified,
  the default FBURL property is indicated with the PREF parameter. The
  FTP or HTTP type of URI points to an iCalendar object associated with
  a snapshot of the last six weeks of the user's busy time data. If the
  iCalendar object is represented as a file or document, it's file type
  should be "ifb".

  Intended usage: Refer to section 1.1.







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  Type examples:

     FBURL;PREF:http://www.host1.com/busy/janedoe
     FBURL:FTP://ftp.host.com/busy/project-a.ifb

2.3.2  CALADRURI Property IANA Registration

  To: [email protected]

  Subject: Registration of CALADRURI type for application/directory
  MIME type vCard profile.

  Type name: CALADRURI

  Type purpose: To specify the location to which an event request
  should be sent for the user.

  Type encoding: 8bit

  Type value: A single URI value.

  Type special notes: Where multiple CALADRURI properties are
  specified, the default CALADRURI property is indicated with the PREF
  parameter.

  Intended usage: Refer to section 1.2.

  Type examples:

     CALADRURI;PREF:mailto:[email protected]





















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2.3.3  CAPURI Property IANA Registration

  To: [email protected]

  Subject: Registration of CAPURI type for application/directory MIME
  type vCard profile.

  Type name: CAPURI

  Type purpose: To specify a protocol independent location from which a
  calendaring and scheduling client (i.e., CUA) can communicate with a
  user's entire calendar.

  Type encoding: 8bit

  Type value: A single URI value.

  Type special notes: Where multiple CAPURI properties are specified,
  the default CAPURI property is indicated with the PREF parameter.

  Intended usage: Refer to section 1.3.

2.3.4 CALURI Property IANA Registration

  To: [email protected]

  Subject: Registration of CALURI type for text/directory MIME type
  vCard profile.

  Type name: CALURI

  Type purpose: To specify the URI for a user's calendar in a vCard
  object.

  Type encoding: 8bit

  Type value type: A single URI value.

  Type special notes: Where multiple CALURI properties are specified,
  the default CALURI property is indicated with the PREF parameter. The
  property should contain a URI pointing to an iCalendar object
  associated with a snapshot of the user's calendar store. If the
  iCalendar object is represented as a file or document, it's file type
  should be "ics".

  Intended usage: Refer to section 1.4.





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  Type examples:

     CALURI;PREF:http://cal.host1.com/calA
     CALURI:ftp://ftp.host1.com/calA.ics

2.4 Directory Lookup Using The LDAP v3 Protocol

  Another way to obtain these URIs is to look them up in a directory
  using the LDAP protocol [1].

  If a user's URIs can be found using directory lookup (i.e., searching
  for one of the LDAP schema extensions defined below), they should, in
  general, be considered "more up-to-date" than URIs in any vCards that
  are stored locally.

2.4.1 LDAP Schema Extensions

  In order to encode the calendaring URIs in the directory, the
  following are defined:

  - One object class:

     - calEntry

  - Eight attributes:

     - calCalURI

     - calFBURL

     - calCAPURI

     - calCalAdrURI

     - calOtherCalURIs

     - calOtherFBURLs

     - calOtherCAPURIs

     - calOtherCalAdrURIs

  The calCalURI contains the URI to a snapshot of the user's entire
  default calendar. The calFBURL contains the URI to the user's default
  busy time data. The calCAPURI represents contains a URI that can be
  used to communicate with the user's calendar. The calCalAdrURI
  contains a URI that points to the location to which event requests
  should be sent for that user.



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  The calOtherCalURIs is a multi-valued property containing URIs to
  snapshots of other calendars that the user may have. The
  calOtherFBURLs is a multi-valued property containing URIs to other
  free/busy data that the user may have. The calOtherCAPURIs attribute
  is a multi-valued property containing URIs to other calendars that
  the user may have. The calOtherCalAdrURIs attribute is a multi-valued
  property containing URIs to other locations that a user may want
  event requests sent to.

  There is no predetermined order to the values in either multi-valued
  property.

2.4.2  Notation

  The notation used in this memo is the same as that used in [2].

2.4.3  Object Definitions

2.4.3.1  calEntry

  The Calendar Entry is a class derived from "TOP" [2], which contains
  the four calendaring attributes.

     (1.2.840.113556.1.5.87
       NAME 'calEntry'
       TOP
       AUXILIARY
       MAY (calCalURI calFBURL calOtherCalURIs calOtherFBURLs calCAPURI
       calOtherCAPURLs)
     )

2.4.4  Attribute Definitions

2.4.4.1 calCalURI

     (1.2.840.113556.1.4.478
       NAME 'calCalURI'
       EQUALITY caseIgnoreMatch
       SUBSTRING caseIgnoreMatch
       SYNTAX 'IA5String'
       USAGE userApplications
     )

2.4.4.2  calFBURL

     (1.2.840.113556.1.4.479
       NAME 'calFBURL'
       EQUALITY caseIgnoreMatch



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       SUBSTRING caseIgnoreMatch
       SYNTAX 'IA5String'
       USAGE userApplications
     )

2.4.4.3  calCAPURI

     (1.2.840.113556.1.4.480
       NAME 'calCAPURI'
       EQUALITY caseIgnoreMatch
       SUBSTRING caseIgnoreMatch
       SYNTAX 'IA5String'
       USAGE userApplications
     )

2.4.4.4  calCalAdrURI

     (1.2.840.113556.1.4.481
       NAME 'calCalAdrURI'
       EQUALITY caseIgnoreMatch
       SUBSTRING caseIgnoreMatch
       SYNTAX 'IA5String'
       USAGE userApplications
     )

2.4.4.5  calOtherCalURIs

       (1.2.840.113556.1.4.482
       NAME 'calOtherCalURIs'
       EQUALITY caseIgnoreMatch
       SUBSTRING caseIgnoreMatch
       SYNTAX 'IA5String'
       MULTI-VALUE
       USAGE userApplications
     )

2.4.4.6  calOtherFBURLs

     (1.2.840.113556.1.4.483
       NAME 'calOtherFBURLs'
       EQUALITY caseIgnoreMatch
       SUBSTRING caseIgnoreMatch
       SYNTAX 'IA5String'
       MULTI-VALUE
       USAGE userApplications
     )





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2.4.4.7  calOtherCAPURIs

     (1.2.840.113556.1.4.484
       NAME 'calOtherCAPURIs'
       EQUALITY caseIgnoreMatch
       SUBSTRING caseIgnoreMatch
       SYNTAX 'IA5String'
       MULTI-VALUE
       USAGE userApplications
     )

2.4.4.8  calOtherCalAdrURIs

     (1.2.840.113556.1.4.485
       NAME 'calOtherCalAdrURIs'
       EQUALITY caseIgnoreMatch
       SUBSTRING caseIgnoreMatch
       SYNTAX 'IA5String'
       MULTI-VALUE
       USAGE userApplications
     )

3  IANA Considerations

  This memo defines IANA registered extensions to the attributes
  defined by LDAP [1] and vCard [3].

  IANA registration proposals for vCard are to be emailed to the
  registration agent for the "text/directory" MIME content-type,
  <MAILTO:  [email protected]> using the format defined in
  [3].

4  Security Considerations

  Standard vCard and LDAP security rules and support apply for the
  extensions described in this document, and there are no special
  security issues for these extensions.

  Please note, though, that LDAP servers may permit anonymous clients
  to refresh entries which they did not create. Servers are also
  permitted to control a refresh access to an entry by requiring
  clients to bind before issuing a RefreshRequest. This will have
  implications on the server performance and scalability.

  Please also note, though, that vCard objects may have been created by
  an entity other than that represented by the vCard. Recipients should
  be certain of the source that generated the vCard.




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  Also, care should be taken in making use of information obtained from
  directory servers that has been supplied by client, as it may now be
  out of date. In many networks, for example, IP addresses are
  automatically assigned when a host connects to the network, and may
  be reassigned if that host later disconnects. An IP address obtained
  from the directory may no longer be assigned to the host that placed
  the address in the directory. This issue is not specific to LDAP or
  dynamic directories.

5  Acknowledgments

  The authors wish to acknowledge the work of Alec Dun, who acted as an
  author for the early drafts of this memo. In addition, this document
  received input from the various participants in the IETF CALSCH
  Working Group discussions.

6  Authors' Addresses

  The following address information is provided in a vCard v3.0 [3],
  Electronic Business Card, format.

  BEGIN:VCARD
  VERSION:3.0
  N:Small;Tony
  FN:Tony Small
  ORG:XpertSite.Com
  ADR;TYPE=WORK,POSTAL,PARCEL:;;4700 42nd Ave. SW, Suite 440;
   Seattle;WA;98116;USA
  TEL;TYPE=WORK,MSG:+1-206-937-9972
  TEL;TYPE=WORK,FAX:+1-206-936-7329
  EMAIL;TYPE=INTERNET:[email protected]
  CALADRURI:MAILTO:[email protected]
  END:VCARD

  BEGIN:VCARD
  VERSION:3.0
  N:Hennessy;Denis
  FN:Denis Hennessy
  ORG:ISOCOR
  ADR;TYPE=WORK,POSTAL,PARCEL:;;42-47 Lower Mount St;
   Dublin 2;Ireland
  TEL;TYPE=WORK,MSG:+353-1-676-0366
  TEL;TYPE=WORK,FAX:+353-1-676-0856
  EMAIL;TYPE=INTERNET:[email protected]
  CALADRURI:MAILTO:[email protected]
  END:VCARD





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  BEGIN:VCARD
  VERSION:3.0
  N:Dawson;Frank
  FN:Frank Dawson
  ORG:Lotus Development Corporation
  ADR;TYPE=WORK,POSTAL,PARCEL:;;6544 Battleford Drive;
   Raleigh;NC;27613-3502;USA
  TEL;TYPE=WORK,PREF:+1-617-693-8728
  TEL;TYPE=WORK,MSG:+1-919-676-9515
  TEL;TYPE=FAX:+1-617-693-8728
  EMAIL;TYPE=INTERNET,PREF:[email protected]
  EMAIL;TYPE=INTERNET:[email protected]
  CALADRURI;TYPE=PREF:MAILTO:[email protected]
  CALADRURI:MAILTO:[email protected]
  URL:http://home.earthlink.net/~fdawson
  END:VCARD

  This memo is a result of the work of the Internet Engineering Task
  Force Calendaring and scheduling Working Group. The chairman of that
  working group is:

  BEGIN:VCARD
  VERSION:3.0
  N:Egen;Pat
  FN:Pat Egen
  ORG:Engan Consulting
  ADR;TYPE=WORK:;;803 Creek Overlook;Chattanooga;TN;37415;USA
  TEL;TYPE=WORK,VOICE:423.875.2652
  TEL;TYPE=WORK,FAX:423.875.2017
  EMAIL:[email protected]
  URL:http://www.egenconsulting.com
  CALADRURI:MAILTO:[email protected]
  END:VCARD


















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7  Bibliography

  [1] Wahl, M., Howes, T. and S. Kille, "Lightweight Directory Access
      Protocol (v3)", RFC 2251, December 1997.

  [2] Wahl, M., Coulbeck, A., Howes, T. and  S. Kille, "Lightweight
      Directory Access Protocol (v3): Attribute Syntax Definitions",
      RFC 2252, December 1997.

  [3] Dawson, F. and  T. Howes, "vCard MIME Directory Profile", RFC
      2426, September 1998.

  [4] Dawson, F. and D. Stenerson, "Internet Calendaring and Scheduling
      Core Object Specification (iCalendar)", RFC 2445, November 1997.

  [5] Dawson, F. and S. Mansour, "iCalendar Message-Based
      Interopability Protocal (iMIP)", RFC 2447, November 1997.


































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8  Full Copyright Statement

  Copyright (C) The Internet Society (2000).  All Rights Reserved.

  This document and translations of it may be copied and furnished to
  others, and derivative works that comment on or otherwise explain it
  or assist in its implementation may be prepared, copied, published
  and distributed, in whole or in part, without restriction of any
  kind, provided that the above copyright notice and this paragraph are
  included on all such copies and derivative works.  However, this
  document itself may not be modified in any way, such as by removing
  the copyright notice or references to the Internet Society or other
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