Network Working Group Tony Small, Microsoft Corporation INTERNET-DRAFT Denis Hennessy, ISOCOR Calendaring and Scheduling Working Group Frank Dawson, Lotus Expires six months from June 11, 1998 Calendar attributes for vCard and LDAP draft-ietf-calsch-locating-00.txt Status of this Memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." To view the entire list of current Internet-Drafts, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net (Northern Europe), ftp.nis.garr.it (Southern Europe), munnari.oz.au (Pacific Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu (US West Coast). 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 draft 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. 1. URIs This draft defines four classes of URIs. URIs are more useful if it is understood what the URIs point to. Here is a brief description: INTERNET-DRAFT Locating A Calendar User June 1998 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 [10] 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 [10]. For example: BEGIN:VCALENDAR VERSION:2.0 PRODID:-//hacksw/handcal//NONSGML v1.0//EN METHOD:PUBLISH BEGIN:VFREEBUSY ATTENDEE:MAILTO:jane_doe@host1.com 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 free/busy inforation. 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. 1.2 Calendar Address URI (CALADRURI) The calendar address URI is defined to be a transport independent communication end-point for a user. The organizer's calendaring and scheduling client (ie. CUA) would use this URI to determine where to send an event request when organizing a meeting with a particular attendee. If the user prefers to receive event requests via iMIP, then the user would provide a "mailto" URI containing the user's e-mail address. [13] For example: "mailto:user@host1.com" INTERNET-DRAFT Locating A Calendar User June 1998 The URI for an iRIP user is yet to be defined, but that is another possible URI value in this property. [14] 1.3. 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. 1.4 Calendar URI (CALURI) The Calendar URI is defined to be a protocol independent location from which a calendaring and scheduling client (ie. 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. 1.5. 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, INTERNET-DRAFT Locating A Calendar User June 1998 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. 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. 2.2.1. vCard Schema Extensions Since the vCard [8] 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. Here is a simple example of a vCard containing a "FBURL" and a "CALURI". BEGIN:VCARD VERSION:3.0 FN:Alec Dun N:Dun;Alec INTERNET-DRAFT Locating A Calendar User June 1998 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:user@host1.com CALADRURI;PREF:mailto:user@host1.com 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 2.2.1.1 FBURL Property IANA Registration To: ietf-mime-directory@imc.org 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. Type examples: FBURL;PREF:http://www.host1.com/busy/janedoe FBURL:FTP://ftp.host.com/busy/project-a.ifb 2.2.1.2 CALADRURI Property IANA Registration To: ietf-mime-directory@imc.org 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. INTERNET-DRAFT Locating A Calendar User June 1998 Type examples: CALADRURI;PREF:mailto:janedoe@host.com 2.2.1.3 CAPURI Property IANA Registration To: ietf-mime-directory@imc.org 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. 2.2.1.4 CALURI Property IANA Registration To: ietf-mime-directory@imc.org 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 valuetype: 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. Type examples: CALURI;PREF:http://cal.host1.com/calA CALURI:ftp://ftp.host1.com/calA.ics 2.3. 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. If an organizer knows an attendee's e-mail address, then using DNS, the attendee's directory server can be found. The mechanism for this is described in detail in [7]. From the directory server, the client INTERNET-DRAFT Locating A Calendar User June 1998 can look up the URLs for a user's calendar. Here's a summary of how it works. For more detail, please see the draft [7]. The client first parses the domain name out from the rfc822 mailbox name. For the fictitious mailbox "janedoe@host1.com", the domain name would be "host1.com". Given the domain name, the client prepends "ldap.tcp" to the domain name and formulating a host. Next the client retrieves the queries the DNS server for the SRV record for "ldap.tcp.host1.com". The mechanism for adding "ldap.tcp" onto the original domain name is described in detail in [5]. The DNS server returns the IP address for the associated server for 'ldap.tcp.host1.com'. Once the IP address for the LDAP server has been obtained, the client constructs a DN from which to search using the DNS name. In this case, it would be "DC=host1,DC=COM". The mechanism to construct the DN is described in detail in [6]. With the IP address and the DN, the client issues a search request to the server where the attribute named "mail" [4] "equalityMatch"es the user's email address. From the first matching entry, client obtains the calendaring and scheduling URLs. If a user's URIs can be found using directory lookup, they should, in general, be considered "more up-to-date" than URIs in any vCards that are stored locally. 2.3.1. LDAP Schema Extensions In order to encode the calendaring URIs in the directory, the following are defined: one object class: @ calEntry and 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 INTERNET-DRAFT Locating A Calendar User June 1998 contains a URI that points to the location to which event requests should be sent for that user. 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. 2.3.2. Notation The notation used in this document is the same as that used in [2]. 2.3.3. Object Definitions 2.3.3.1. 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) ) 2.3.4. Attribute Definitions 2.3.4.1. calCalURI ( 1.2.840.113556.1.4.478 NAME 'calCalURI' EQUALITY caseIgnoreMatch SUBSTRING caseIgnoreMatch SYNTAX 'Directory String' USAGE userApplications ) 2.3.4.2. calFBURL INTERNET-DRAFT Locating A Calendar User June 1998 ( 1.2.840.113556.1.4.479 NAME 'calFBURL' EQUALITY caseIgnoreMatch SUBSTRING caseIgnoreMatch SYNTAX 'Directory String' USAGE userApplications ) 2.3.4.3. calCAPURI ( 1.2.840.113556.1.4.480 NAME 'calCAPURI' EQUALITY caseIgnoreMatch SUBSTRING caseIgnoreMatch SYNTAX 'Directory String' USAGE userApplications ) 2.3.4.4. calCalAdrURI ( 1.2.840.113556.1.4.481 NAME 'calCalAdrURI' EQUALITY caseIgnoreMatch SUBSTRING caseIgnoreMatch SYNTAX 'Directory String' USAGE userApplications ) 2.3.4.5. calOtherCalURIs ( 1.2.840.113556.1.4.482 NAME 'calOtherCalURIs' EQUALITY caseIgnoreMatch SUBSTRING caseIgnoreMatch SYNTAX 'Directory String' MULTI-VALUE USAGE userApplications ) 2.3.4.6. calOtherFBURLs ( 1.2.840.113556.1.4.483 NAME 'calOtherFBURLs' EQUALITY caseIgnoreMatch INTERNET-DRAFT Locating A Calendar User June 1998 SUBSTRING caseIgnoreMatch SYNTAX 'Directory String' MULTI-VALUE USAGE userApplications ) 2.3.4.7. calOtherCAPURIs ( 1.2.840.113556.1.4.484 NAME 'calOtherCAPURIs' EQUALITY caseIgnoreMatch SUBSTRING caseIgnoreMatch SYNTAX 'Directory String' MULTI-VALUE USAGE userApplications ) 2.3.4.8. calOtherCalAdrURIs ( 1.2.840.113556.1.4.485 NAME 'calOtherCalAdrURIs' EQUALITY caseIgnoreMatch SUBSTRING caseIgnoreMatch SYNTAX 'Directory String' MULTI-VALUE USAGE userApplications ) Authors' Addresses BEGIN:VCARD VERSION:2.1 N:Small;Tony FN:Tony Small ORG:Microsoft Corporation ADR;WORK;POSTAL;PARCEL:;;One Microsoft Way; Redmond;WA;98052-6399;USA TEL;WORK;MSG:+1-425-703-2190 TEL;WORK;FAX:+1-206-936-7329 EMAIL;INTERNET:tonysm@Microsoft.com CALADRURI:MAIL-TO:tonysm@Microsoft.com END:VCARD BEGIN:VCARD VERSION:2.1 N:Hennessy;Denis FN:Denis Hennessy INTERNET-DRAFT Locating A Calendar User June 1998 ORG:ISOCOR ADR;WORK;POSTAL;PARCEL:;;42-47 Lower Mount St; Dublin 2;Ireland TEL;WORK;MSG:+353-1-676-0366 TEL;WORK;FAX:+353-1-676-0856 EMAIL;INTERNET:denis.hennessy@isocor.com CALADRURI:MAIL-TO:denis.hennessy@isocor.com END:VCARD BEGIN:VCARD VERSION:2.1 N:Dawson;Frank FN:Frank Dawson ORG:Lotus Development Corporation ADR;WORK;POSTAL;PARCEL:;;6544 Battleford Drive; Raleigh;NC;27613-3502;USA TEL;WORK;MSG:+1-919-676-9515 TEL;WORK;FAX:+1-919-676-9564 EMAIL;INTERNET;PREF:Frank_Dawson@Lotus.com EMAIL;INTERNET:fdawson@earthlink.net CALADRURI;PREF:MAIL-TO:Frank_Dawson@Lotus.com CALADRURI:MAIL-TO:fdawson@earthlink.net URI:http://home.earthlink.net/~fdawson END:VCARD Bibliography [1] M. Wahl, T. Howes, S. Kille, 'Lightweight Directory Access Protocol (v3)', RFC 2251, December 1997, [2] M. Wahl, A. Coulbeck, T. Howes, S. Kille, 'Lightweight Directory Access Protocol (v3): Attribute Syntax Definitions', RFC 2252, December 1997, [3] M. Wahl, A Summary of the X.500(96) User Schema for use with LDAPv3', RFC 2256, December 1997, [4] The Directory: Selected Attribute Types. ITU-T Recommendation X.520, 1993. [5] The Directory: Selected Object Classes. ITU-T Recommendation X.521, 1993. [6] P. Leach `Selecting a server from among many replicas', INTERNET DRAFT , February 1997 INTERNET-DRAFT Locating A Calendar User June 1998 [7] P. Leach `Locating Native Internet LDAP Servers', INTERNET DRAFT , March 1997 [8] F. Dawson, T. Howes, 'vCard MIME Directory Profile', INTERNET-DRAFT , July 1997 [9] A. Gulbrandsen, P. Vixie, "A DNS RR for specifying the location of services (DNS SRV)", RFC 2052, , October 1996. [10] F. Dawson, D. Stenerson 'Internet Calendaring and Scheduling Core Ojbect Specification (iCalendar)', Nov 1997, [11] Mockapetris, P., "Domain Names - Implementation and Specification", STD 13, RFC 1035, USC/Information Sciences Institute, November 1987. [12] Network Applications Consortium 'Lightweight Internet Person Schema', April 1997, [13] F. Dawson, S. Mansour `iCalendar Message-Based Interopability Protocal (iMIP)', March 1998, [14] A. Courtemanche, S. Mansour, P. O'Leary `iCalendar Real-Time Interopability Protocol ( iRIP)', November 1997,