draft-ietf-calext-availability-03.txt   draft-ietf-calext-availability-04.txt 
Network Working Group C. Daboo Network Working Group C. Daboo
Internet-Draft Apple Internet-Draft Apple
Intended status: Standards Track M. Douglass Updates: 5545,4791,6638 (if approved) M. Douglass
Expires: December 24, 2016 Spherical Cow Group Intended status: Standards Track Spherical Cow Group
June 22, 2016 Expires: January 8, 2017 July 7, 2016
Calendar Availability Calendar Availability
draft-ietf-calext-availability-03 draft-ietf-calext-availability-04
Abstract Abstract
This document specifies a new iCalendar calendar component that This document specifies a new iCalendar (RFC 5545) calendar component
allows the publication of available and unavailable time periods that allows the publication of available and unavailable time periods
associated with a calendar user. This component can be used in associated with a calendar user. This component can be used in
standard iCalendar free-busy lookups, including iTIP free-busy standard iCalendar free-busy lookups, including iTIP (RFC 5546 )
requests, to generate repeating blocks of available or busy time with free-busy requests, to generate repeating blocks of available or busy
exceptions as needed. time with exceptions as needed.
This document also defines extensions to CalDAV calendar-access and This document also defines extensions to Calendaring Extensions to
calendar-auto-schedule which specify how this new calendar component WebDAV (CalDAV) calendar access protocol (RFC 4791) and the
can be used when doing free-busy time evaluation in CalDAV. associated scheduling protocol (RFC 6638) to specify how this new
calendar component can be used when evaluating free-busy time.
Editorial Note (To be removed by RFC Editor before publication) Editorial Note (To be removed by RFC Editor before publication)
Discussion of this specification is taking place on the mailing list Discussion of this specification is taking place on the mailing list
http://lists.osafoundation.org/mailman/listinfo/ietf-caldav . http://lists.osafoundation.org/mailman/listinfo/ietf-caldav .
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
skipping to change at page 1, line 45 skipping to change at page 1, line 46
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 24, 2016. This Internet-Draft will expire on January 8, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 28 skipping to change at page 2, line 28
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions Used in This Document . . . . . . . . . . . . . . 3 2. Conventions Used in This Document . . . . . . . . . . . . . . 3
3. iCalendar Extensions . . . . . . . . . . . . . . . . . . . . 4 3. iCalendar Extensions . . . . . . . . . . . . . . . . . . . . 4
3.1. VAVAILABILITY Component . . . . . . . . . . . . . . . . . 4 3.1. VAVAILABILITY Component . . . . . . . . . . . . . . . . . 4
3.2. Busy Time Type . . . . . . . . . . . . . . . . . . . . . 10 3.2. Busy Time Type . . . . . . . . . . . . . . . . . . . . . 10
4. Combining VAVAILABILITY components . . . . . . . . . . . . . 10 4. Combining VAVAILABILITY components . . . . . . . . . . . . . 10
5. Calculating Free-Busy Time . . . . . . . . . . . . . . . . . 11 5. Calculating Free-Busy Time . . . . . . . . . . . . . . . . . 12
5.1. Examples . . . . . . . . . . . . . . . . . . . . . . . . 13 5.1. Examples . . . . . . . . . . . . . . . . . . . . . . . . 13
6. Use with iTIP . . . . . . . . . . . . . . . . . . . . . . . . 14 6. Use with iTIP . . . . . . . . . . . . . . . . . . . . . . . . 15
7. CalDAV Extensions . . . . . . . . . . . . . . . . . . . . . . 15 7. CalDAV Extensions . . . . . . . . . . . . . . . . . . . . . . 15
7.1. CalDAV Requirements Overview . . . . . . . . . . . . . . 15 7.1. CalDAV Requirements Overview . . . . . . . . . . . . . . 15
7.2. New features in CalDAV . . . . . . . . . . . . . . . . . 15 7.2. New features in CalDAV . . . . . . . . . . . . . . . . . 15
8. Security Considerations . . . . . . . . . . . . . . . . . . . 19 8. Security Considerations . . . . . . . . . . . . . . . . . . . 19
9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 19 9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 19
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
10.1. Component Registrations . . . . . . . . . . . . . . . . 20 10.1. Component Registrations . . . . . . . . . . . . . . . . 20
10.2. Property Registrations . . . . . . . . . . . . . . . . . 20 10.2. Property Registrations . . . . . . . . . . . . . . . . . 20
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20
12. Normative References . . . . . . . . . . . . . . . . . . . . 20 12. Normative References . . . . . . . . . . . . . . . . . . . . 20
Appendix A. Example Calendar #1 . . . . . . . . . . . . . . . . 21 Appendix A. Example Calendar #1 . . . . . . . . . . . . . . . . 21
Appendix B. Change History (To be removed by RFC Editor before Appendix B. Example Calendar #2 . . . . . . . . . . . . . . . . 21
publication) . . . . . . . . . . . . . . . . . . . . 21 Appendix C. Change History (To be removed by RFC Editor before
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24 publication) . . . . . . . . . . . . . . . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
1. Introduction 1. Introduction
Calendar users often have regular periods of time when they are Calendar users often have regular periods of time when they are
either available to be scheduled or always unavailable. For example, either available to be scheduled or always unavailable. For example,
an office worker will often wish only to appear free to their work an office worker will often wish only to appear free to their work
colleagues during normal 'office hours' (e.g., Monday through Friday, colleagues during normal 'office hours' (e.g., Monday through Friday,
9 am through 5 pm). Or, a university professor might only be 9 am through 5 pm). Or, a university professor might only be
available to students during a set period of time (e.g., Thursday available to students during a set period of time (e.g., Thursday
afternoons, 2 pm through 5 pm during term time only). Ideally users afternoons, 2 pm through 5 pm during term time only). Ideally users
skipping to change at page 7, line 24 skipping to change at page 7, line 24
location for another part of the week (but see Section 9 for when location for another part of the week (but see Section 9 for when
it is appropriate to add additional data like this). it is appropriate to add additional data like this).
Example: The following is an example of a "VAVAILABILITY" calendar Example: The following is an example of a "VAVAILABILITY" calendar
component used to represent the availability of a user, always component used to represent the availability of a user, always
available Monday through Friday, 9:00 AM to 5:00 PM in the available Monday through Friday, 9:00 AM to 5:00 PM in the
America/Montreal time zone: America/Montreal time zone:
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com ORGANIZER:mailto:bernard@example.com
UID:vavail-1@example.com UID:0428C7D2-688E-4D2E-AC52-CD112E2469DF
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-A@example.com UID:34EDA59B-6BB1-4E94-A66C-64999089C0AF
SUMMARY:Monday to Friday from 9:00 to 17:00 SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Montreal:20111002T090000 DTSTART;TZID=America/Montreal:20111002T090000
DTEND;TZID=America/Montreal:20111002T170000 DTEND;TZID=America/Montreal:20111002T170000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
The following is an example of a "VAVAILABILITY" calendar The following is an example of a "VAVAILABILITY" calendar
component used to represent the availability of a user available component used to represent the availability of a user available
Monday through Thursday, 9:00 AM to 5:00 PM at the main office, Monday through Thursday, 9:00 AM to 5:00 PM at the main office,
and Friday 9:00 AM to 12:00 PM in the branch office in the and Friday 9:00 AM to 12:00 PM in the branch office in the
America/Montreal time zone between October 2nd and December 2nd America/Montreal time zone between October 2nd and December 2nd
2011: 2011:
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com ORGANIZER:mailto:bernard@example.com
UID:vavail-1@example.com UID:84D0F948-7FC6-4C1D-BBF3-BA9827B424B5
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Montreal:20111002T000000 DTSTART;TZID=America/Montreal:20111002T000000
DTEND;TZID=America/Montreal:20111202T000000 DTEND;TZID=America/Montreal:20111202T000000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-A@example.com UID:7B33093A-7F98-4EED-B381-A5652530F04D
SUMMARY:Monday to Thursday from 9:00 to 17:00 SUMMARY:Monday to Thursday from 9:00 to 17:00
DTSTART;TZID=America/Montreal:20111002T090000 DTSTART;TZID=America/Montreal:20111002T090000
DTEND;TZID=America/Montreal:20111002T170000 DTEND;TZID=America/Montreal:20111002T170000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH
LOCATION:Main Office LOCATION:Main Office
END:AVAILABLE END:AVAILABLE
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-B@example.com UID:DF39DC9E-D8C3-492F-9101-0434E8FC1896
SUMMARY:Friday from 9:00 to 12:00 SUMMARY:Friday from 9:00 to 12:00
DTSTART;TZID=America/Montreal:20111006T090000 DTSTART;TZID=America/Montreal:20111006T090000
DTEND;TZID=America/Montreal:20111006T120000 DTEND;TZID=America/Montreal:20111006T120000
RRULE:FREQ=WEEKLY RRULE:FREQ=WEEKLY
LOCATION:Branch Office LOCATION:Branch Office
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
The following is an example of three "VAVAILABILITY" calendar The following is an example of three "VAVAILABILITY" calendar
components used to represent the availability of a traveling components used to represent the availability of a traveling
worker: Monday through Friday, 9:00 AM to 5:00 PM each day. worker: Monday through Friday, 9:00 AM to 5:00 PM each day.
However, for three weeks the calendar user is working in Montreal, However, for three weeks the calendar user is working in Montreal,
then one week in Los Angeles, then back to Montreal. Note that then one week in Denver, then back to Montreal. Note that each
each overall period is covered by separate "VAVAILABILITY" overall period is covered by separate "VAVAILABILITY" components.
components. The last of these has no DTEND so continues on "for The last of these has no DTEND so continues on "for ever". This
ever". This example shows one way "blocks" of available time can example shows one way "blocks" of available time can be
be represented. See Section 4 for another approach using represented. See Section 4 for another approach using priorities.
priorities.
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com ORGANIZER:mailto:bernard@example.com
UID:vavail-1@example.com UID:BE082249-7BDD-4FE0-BDBA-DE6598C32FC9
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Montreal:20111002T000000 DTSTART;TZID=America/Montreal:20111002T000000
DTEND;TZID=America/Montreal:20111023T030000 DTEND;TZID=America/Montreal:20111023T030000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-A@example.com UID:54602321-CEDB-4620-9099-757583263981
SUMMARY:Monday to Friday from 9:00 to 17:00 SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Montreal:20111002T090000 DTSTART;TZID=America/Montreal:20111002T090000
DTEND;TZID=America/Montreal:20111002T170000 DTEND;TZID=America/Montreal:20111002T170000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
LOCATION:Montreal LOCATION:Montreal
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com ORGANIZER:mailto:bernard@example.com
UID:vavail-2@example.com UID:A1FF55E3-555C-433A-8548-BF4864B5621E
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Los_Angeles:20111023T000000 DTSTART;TZID=America/Denver:20111023T000000
DTEND;TZID=America/Los_Angeles:20111030T000000 DTEND;TZID=America/Denver:20111030T000000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-2-A@example.com UID:57DD4AAF-3835-46B5-8A39-B3B253157F01
SUMMARY:Monday to Friday from 9:00 to 17:00 SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Los_Angeles:20111023T090000 DTSTART;TZID=America/Denver:20111023T090000
DTEND;TZID=America/Los_Angeles:20111023T170000 DTEND;TZID=America/Denver:20111023T170000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
LOCATION:Los Angeles LOCATION:Denver
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com ORGANIZER:mailto:bernard@example.com
UID:vavail-3@example.com UID:1852F9E1-E0AA-4572-B4C4-ED1680A4DA40
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Montreal:20111030T030000 DTSTART;TZID=America/Montreal:20111030T030000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-3-A@example.com UID:D27C421F-16C2-4ECB-8352-C45CA352C72A
SUMMARY:Monday to Friday from 9:00 to 17:00 SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Montreal:20111030T090000 DTSTART;TZID=America/Montreal:20111030T090000
DTEND;TZID=America/Montreal:20111030T170000 DTEND;TZID=America/Montreal:20111030T170000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
LOCATION:Montreal LOCATION:Montreal
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
3.2. Busy Time Type 3.2. Busy Time Type
skipping to change at page 11, line 41 skipping to change at page 11, line 41
Note that, if any "VAVAILABILITY" component completely covers the Note that, if any "VAVAILABILITY" component completely covers the
date range of interest, then any lower priority "VAVAILABILITY" date range of interest, then any lower priority "VAVAILABILITY"
components can be ignored. components can be ignored.
Typically, a calendar user's "default" availability (e.g., business Typically, a calendar user's "default" availability (e.g., business
hours of Monday through Friday, 9:00 am to 5:00 pm) would use the hours of Monday through Friday, 9:00 am to 5:00 pm) would use the
lowest level of priority: zero. Any overrides to the "default" would lowest level of priority: zero. Any overrides to the "default" would
use higher levels as needed. To avoid having to keep readjusting the use higher levels as needed. To avoid having to keep readjusting the
"PRIORITY" property value when an override has to be "inserted" "PRIORITY" property value when an override has to be "inserted"
between two existing components, priority values SHOULD be "spaced between two existing components, priority values SHOULD be "spaced
out" over the full range of values. e.g., the "default" availability out" over the full range of values. The table below illustrates this
is created with priority zero, then the first override created with via an example. The first row shows the priority range from low to
priority 5, a subsequent availability can be inserted between the two high, the second row shows the corresponding "PRIORITY" property
by using priority 7, and another, taking precedence over all existing value, and the third row shows which "VAVAILABILITY" component has
ones, with priority 3. that priority. The "default" availability is created with priority
zero (shown as {a} in the table), then the first override created
with priority 5 (shown as {b} in the table), a subsequent
availability can be inserted between the two by using priority 7
(shown as {c} in the table), and another, taking precedence over all
existing ones, with priority 3 (shown as {d} in the table). As seen
in the table, additional "slots" are open for more "VAVAILABILITY"
components to be added with other priorities if needed.
+-----+----+----+-----+----+-----+----+-----+----+------+
| Low | | | | | | | | | High |
+-----+----+----+-----+----+-----+----+-----+----+------+
| 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
+-----+----+----+-----+----+-----+----+-----+----+------+
| {a} | | | {c} | | {b} | | {d} | | |
+-----+----+----+-----+----+-----+----+-----+----+------+
5. Calculating Free-Busy Time 5. Calculating Free-Busy Time
This section describes how free-busy time information for a calendar This section describes how free-busy time information for a calendar
user is calculated in the presence of "VAVAILABILITY" calendar user is calculated in the presence of "VAVAILABILITY" calendar
components. components.
An iCalendar "VFREEBUSY" component is used to convey "rolled-up" An iCalendar "VFREEBUSY" component is used to convey "rolled-up"
free-busy time information for a calendar user. This can be free-busy time information for a calendar user. This can be
generated as the result of an iTIP free-busy [RFC5546] request or generated as the result of an iTIP free-busy [RFC5546] request or
through some other mechanism (e.g., a CalDAV calendar-access through some other mechanism (e.g., a CalDAV calendar-access
CALDAV:free-busy-query REPORT). CALDAV:free-busy-query REPORT).
When one or more "VAVAILABILITY" components are present and intersect When one or more "VAVAILABILITY" components are present and intersect
the time-range for the free-busy request, first available time is the time-range for the free-busy request, first the available time is
calculated, as outlined in Section 4. Once that is done, regular calculated, as outlined in Section 4. Once that is done, regular
"VEVENT" and "VFREEBUSY" components can be "overlaid" in the usual "VEVENT" and "VFREEBUSY" components can be "overlaid" in the usual
way to block out time. way to block out time.
An example procedure for this is as follows: An example procedure for this is as follows:
1. Initially mark the entire period of the free-busy request as 1. Initially mark the entire period of the free-busy request as
free. free.
2. For each "VAVAILABILITY" component ordered by PRIORITY (lowest to 2. For each "VAVAILABILITY" component ordered by PRIORITY (lowest to
highest): highest):
1. Determine if the "VAVAILABILITY" intersects the time-range of A. Determine if the "VAVAILABILITY" intersects the time-range of
the free-busy request. If not ignore it. the free-busy request. If not ignore it.
2. Determine if the "VAVAILABILITY" is completely overridden by B. Determine if the "VAVAILABILITY" is completely overridden by
a higher priority component. If so ignore it. a higher priority component. If so ignore it.
3. For the time period covered by the "VAVAILABILITY" component, C. For the time period covered by the "VAVAILABILITY" component,
mark time in the free-busy request result set as busy, using mark time in the free-busy request result set as busy, using
the busy time type derived from the "BUSYTYPE" property in the busy time type derived from the "BUSYTYPE" property in
the "VAVAILABILITY" component. the "VAVAILABILITY" component.
4. Append the "VAVAILABILITY" component to a list of components D. Append the "VAVAILABILITY" component to a list of components
for further processing in step 3, if it has not been ignored. for further processing in step 3, if it has not been ignored.
3. For each "VAVAILABILITY" component in the list resulting from 3. For each "VAVAILABILITY" component in the list resulting from
step 2, in order from the first item to the last item: step 2, in order from the first item to the last item:
1. For each "AVAILABLE" component in the "VAVAILABILITY" A. For each "AVAILABLE" component in the "VAVAILABILITY"
component: component:
1. Expand all recurring instances, taking into account i. Expand all recurring instances, taking into account
overridden instances, ignoring instances or parts of overridden instances, ignoring instances or parts of
instances that fall outside of the free-busy request instances that fall outside of the free-busy request time-
time-range or the time period specified by the range or the time period specified by the "VAVAILABILITY"
"VAVAILABILITY" component. component.
2. For each instance, mark the corresponding time in the ii. For each instance, mark the corresponding time in the
free-busy request result set as free. free-busy request result set as free.
4. For each "VEVENT" or "VFREEBUSY" component apply normal free-busy 4. For each "VEVENT" or "VFREEBUSY" component apply normal free-busy
processing within the free-busy request time-range. processing within the free-busy request time-range.
5.1. Examples 5.1. Examples
In the examples below a table is used to represent time slots for the In the examples below a table is used to represent time slots for the
period of a free-busy request. Each time slot is two hours long. period of a free-busy request. Each time slot is two hours long.
The column header represents the hours from midnight local time. The column header represents the hours from midnight local time.
Each row below the column headers represents a step in the free-busy Each row below the column headers represents a step in the free-busy
result set determination, following the procedure outlined above. result set determination, following the procedure outlined above.
Each cell in the rows below the column header contains a single Each cell in the rows below the column header contains a single
character that represents the free-busy type for the corresponding character that represents the free-busy type for the corresponding
time period at the end of the process step represented by the row. time period at the end of the process step represented by the row.
The characters in the row are: The characters in the row are:
+-----------+--------------------------------------------------+ F Represents "FREE" time in that slot.
| Character | Meaning |
+-----------+--------------------------------------------------+
| F | Represents "FREE" time in that slot. |
| B | Represents "BUSY" time in that slot. |
| U | Represents "BUSY-UNAVAILABLE" time in that slot. |
| T | Represents "BUSY-TENTATIVE" time in that slot. |
+-----------+--------------------------------------------------+
5.1.1. Simple Example B Represents "BUSY" time in that slot.
A free-busy request for Monday, 6th November 2011, midnight to U Represents "BUSY-UNAVAILABLE" time in that slot.
midnight in the America/Montreal timezone.
The user's calendar is as shown in Appendix A. This includes one T Represents "BUSY-TENTATIVE" time in that slot.
I Represents data to be ignored in that slot (as per step 2.B
above).
5.1.1. Simple Example
Appendix A shows the user's calendar. This includes one
"VAVAILABILITY" component giving available time within the requested "VAVAILABILITY" component giving available time within the requested
time-range of 8:00 AM to 6:00 PM, together with one "VEVENT" time-range of 8:00 AM to 6:00 PM, together with one "VEVENT"
component representing a two hour meeting starting at 12:00 PM. component representing a two hour meeting starting at 12:00 PM.
A free-busy request for Monday, 6th November 2011, midnight to
midnight in the America/Montreal timezone would be calculated as
follows using the steps described above.
+------+----+----+----+----+----+----+----+----+----+----+----+----+ +------+----+----+----+----+----+----+----+----+----+----+----+----+
| Step | 0 | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 | | Step | 0 | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 |
+------+----+----+----+----+----+----+----+----+----+----+----+----+ +------+----+----+----+----+----+----+----+----+----+----+----+----+
| 1. | F | F | F | F | F | F | F | F | F | F | F | F | | 1. | F | F | F | F | F | F | F | F | F | F | F | F |
| 2. | U | U | U | U | U | U | U | U | U | U | U | U | | 2. | U | U | U | U | U | U | U | U | U | U | U | U |
| 3. | U | U | U | U | F | F | F | F | F | U | U | U | | 3. | U | U | U | U | F | F | F | F | F | U | U | U |
| 4. | U | U | U | U | F | F | B | F | F | U | U | U | | 4. | U | U | U | U | F | F | B | F | F | U | U | U |
+------+----+----+----+----+----+----+----+----+----+----+----+----+ +------+----+----+----+----+----+----+----+----+----+----+----+----+
5.1.2. Further Example 5.1.2. Further Example
The following is another way to represent the availability of the Appendix B shows another way to represent the availability of the
traveling worker shown above. Here we represent their base traveling worker shown above. Here we represent their base
availability of Monday through Friday, 9:00 AM to 5:00 PM each day availability of Monday through Friday, 8:00 AM to 6:00 PM each day
with a "VAVAILABILITY" with default "PRIORITY" (there is no "DTEND" with a "VAVAILABILITY" with default "PRIORITY" (there is no "DTEND"
property so that this availability is unbounded). For the three property so that this availability is unbounded). For the week the
weeks the calendar user is working in Los Angeles, we represent their calendar user is working in Denver (October 23rd through October
availability with a "VAVAILABILITY" component with priority 1, which 30th), we represent their availability with a "VAVAILABILITY"
overrides the base availability. component with priority 1, which overrides the base availability.
There is also a two hour meeting starting at 12:00 PM (in the
America/Denver time zone).
BEGIN:VAVAILABILITY A free-busy request for Monday, 24th October 2011, midnight to
ORGANIZER:mailto:bernard@example.com midnight in the America/Montreal timezone, would be calculated as
UID:vavail-1@example.com follows using the steps described above. Note that there is a two
DTSTAMP:20111005T133225Z hour offset in the in the available time, compared to the previous
DTSTART;TZID=America/Montreal:20111002T000000 example, due to the two hour difference between the time zone of the
BEGIN:AVAILABLE free busy request and the time zone of the user's availability and
UID:avail-1-A@example.com meeting. "2.P0" shows the base availability, and "2.P1" shows the
SUMMARY:Monday to Friday from 9:00 to 17:00 higher priority availability. "3.P1" only shows the higher priority
DTSTART;TZID=America/Montreal:20111002T090000 availability contributing to the overall free busy, since the default
DTEND;TZID=America/Montreal:20111002T170000 availability is ignored (as per step 2.B described above).
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
LOCATION:Montreal +------+----+----+----+----+----+----+----+----+----+----+----+----+
END:AVAILABLE | Step | 0 | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 |
END:VAVAILABILITY +------+----+----+----+----+----+----+----+----+----+----+----+----+
BEGIN:VAVAILABILITY | 1. | F | F | F | F | F | F | F | F | F | F | F | F |
ORGANIZER:mailto:bernard@example.com | 2.P0 | I | I | I | I | I | I | I | I | I | I | I | I |
UID:vavail-2@example.com | 2.P1 | U | U | U | U | U | U | U | U | U | U | U | U |
DTSTAMP:20111005T133225Z | 3.P1 | U | U | U | U | U | F | F | F | F | F | U | U |
DTSTART;TZID=America/Los_Angeles:20111023T000000 | 4. | U | U | U | U | U | F | F | B | F | F | U | U |
DTEND;TZID=America/Los_Angeles:20111030T000000 +------+----+----+----+----+----+----+----+----+----+----+----+----+
PRIORITY:1
BEGIN:AVAILABLE
UID:avail-2-A@example.com
SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Los_Angeles:20111023T090000
DTEND;TZID=America/Los_Angeles:20111023T170000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
LOCATION:Los Angeles
END:AVAILABLE
END:VAVAILABILITY
6. Use with iTIP 6. Use with iTIP
This specification does not define how "VAVAILABILITY" components are This specification does not define how "VAVAILABILITY" components are
used in scheduling messages sent using the iTIP [RFC5546] protocol. used in scheduling messages sent using the iTIP [RFC5546] protocol.
It is expected that future specifications will define how iTIP It is expected that future specifications will define how iTIP
scheduling can make use of "VAVAILABILITY" components. scheduling can make use of "VAVAILABILITY" components.
7. CalDAV Extensions 7. CalDAV Extensions
skipping to change at page 15, line 34 skipping to change at page 15, line 41
feature is supported; feature is supported;
o MUST support iTIP [RFC5546] free-busy requests that aggregate the o MUST support iTIP [RFC5546] free-busy requests that aggregate the
information in any "VAVAILABILITY" components in calendar information in any "VAVAILABILITY" components in calendar
collections that contribute to free-busy, or in any collections that contribute to free-busy, or in any
"VAVAILABILITY" components stored in the CALDAV:calendar- "VAVAILABILITY" components stored in the CALDAV:calendar-
availability property on the CalDAV scheduling inbox collection of availability property on the CalDAV scheduling inbox collection of
the calendar user targeted by the iTIP free-busy request, if the the calendar user targeted by the iTIP free-busy request, if the
CalDAV calendar-auto-schedule feature is available. CalDAV calendar-auto-schedule feature is available.
"VAVAILABILITY" components are treated in a manner similar to Processing of "VAVAILABILITY" components MUST conform to all the
"VEVENT" and "VTODO" components, and MUST satisfy the other
requirements CalDAV imposes on calendar object resources (see requirements CalDAV imposes on calendar object resources (see
Section 4.1 of [RFC4791]). Section 4.1 of [RFC4791]).
7.2. New features in CalDAV 7.2. New features in CalDAV
7.2.1. Calendar Availability Support 7.2.1. Calendar Availability Support
A server supporting the features described in this document MUST A server supporting the features described in this document MUST
include "calendar-availability" as a field in the DAV response header include "calendar-availability" as a field in the DAV response header
from an OPTIONS request. A value of "calendar-availability" in the from an OPTIONS request. A value of "calendar-availability" in the
DAV response header MUST indicate that the server supports all MUST DAV response header indicates to clients that the server supports all
level requirements specified in this document. the requirements specified in this document.
7.2.1.1. Example: Using OPTIONS for the Discovery of Calendar 7.2.1.1. Example: Using OPTIONS for the Discovery of Calendar
Availability Support Availability Support
>> Request << >> Request <<
OPTIONS /home/bernard/calendars/ HTTP/1.1 OPTIONS /home/bernard/calendars/ HTTP/1.1
Host: cal.example.com Host: cal.example.com
>> Response << >> Response <<
skipping to change at page 17, line 46 skipping to change at page 17, line 46
Namespace: urn:ietf:params:xml:ns:caldav Namespace: urn:ietf:params:xml:ns:caldav
Purpose: Defines a "VAVAILABILITY" component that will be used in Purpose: Defines a "VAVAILABILITY" component that will be used in
calculating free-busy time when an iTIP free-busy request is calculating free-busy time when an iTIP free-busy request is
targeted at the calendar user who owns the Inbox. targeted at the calendar user who owns the Inbox.
Conformance: This property MAY be protected and SHOULD NOT be Conformance: This property MAY be protected and SHOULD NOT be
returned by a PROPFIND DAV:allprop request. Support for this returned by a PROPFIND DAV:allprop request. Support for this
property is REQUIRED. The value of this property MUST be a valid property is REQUIRED. The value of this property MUST be a valid
iCalendar object containing a "VAVAILABILITY" component. iCalendar object containing only one "VAVAILABILITY" component,
"VTIMEZONE" components SHOULD NOT be present if [RFC7809] is in and optionally, "VTIMEZONE" components - other iCalendar
effect. For simplicity, only a single "VAVAILABILITY" component components MUST NOT be present. "VTIMEZONE" components SHOULD NOT
MUST be present in the property. For more complex availability be present if [RFC7809] is in effect. For more complex
scenarios, clients can store multiple "VAVAILABILITY" components availability scenarios, clients can store multiple "VAVAILABILITY"
in the calendar user's calendar collections. components in the calendar user's calendar collections.
Description: This property allows a user to specify their Description: This property allows a user to specify their
availability by including an "VAVAILABILITY" component in the availability by including an "VAVAILABILITY" component in the
value of this property. If present, the server MUST use this value of this property. If present, the server MUST use this
"VAVAILABILITY" component when determining free-busy information "VAVAILABILITY" component when determining free-busy information
as part of an iTIP free-busy request being handled by the server. as part of an iTIP free-busy request being handled by the server.
Definition: Definition:
<!ELEMENT calendar-availability (#PCDATA) > <!ELEMENT calendar-availability (#PCDATA) >
skipping to change at page 18, line 26 skipping to change at page 18, line 26
Example: Example:
<C:calendar-availability xmlns:D="DAV:" <C:calendar-availability xmlns:D="DAV:"
xmlns:C="urn:ietf:params:xml:ns:caldav" xmlns:C="urn:ietf:params:xml:ns:caldav"
>BEGIN:VCALENDAR >BEGIN:VCALENDAR
CALSCALE:GREGORIAN CALSCALE:GREGORIAN
PRODID:-//example.com//iCalendar 2.0//EN PRODID:-//example.com//iCalendar 2.0//EN
VERSION:2.0 VERSION:2.0
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
UID:vavail-1@example.com UID:9BADC1F6-0FC4-44BF-AC3D-993BEC8C962A
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Montreal:20111002T000000 DTSTART;TZID=America/Montreal:20111002T000000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-A@example.com UID:6C9F69C3-BDA8-424E-B2CB-7012E796DDF7
SUMMARY:Monday to Friday from 9:00 to 18:00 SUMMARY:Monday to Friday from 9:00 to 18:00
DTSTART;TZID=America/Montreal:20111002T090000 DTSTART;TZID=America/Montreal:20111002T090000
DTEND;TZID=America/Montreal:20111002T180000 DTEND;TZID=America/Montreal:20111002T180000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
END:VCALENDAR END:VCALENDAR
</C:calendar-availability> </C:calendar-availability>
7.2.5. iTIP free-busy requests 7.2.5. iTIP free-busy requests
skipping to change at page 19, line 8 skipping to change at page 19, line 8
owner of the CALDAV:schedule-inbox will include free-busy information owner of the CALDAV:schedule-inbox will include free-busy information
derived from "VAVAILABILITY" components in any calendar collection derived from "VAVAILABILITY" components in any calendar collection
targeted during the request, as described in Section 5. In addition, targeted during the request, as described in Section 5. In addition,
the "VAVAILABILITY" component specified in the CALDAV:calendar- the "VAVAILABILITY" component specified in the CALDAV:calendar-
availability property on the owner's Inbox, MUST be included in the availability property on the owner's Inbox, MUST be included in the
free-busy calculation. free-busy calculation.
8. Security Considerations 8. Security Considerations
Calculation of availability information, particularly with multiple Calculation of availability information, particularly with multiple
overlapping time-ranges, can be complex, and CalDAV servers MAY limit overlapping time-ranges, can be complex, and CalDAV servers MUST
the complexity of such data stored by a client. limit the complexity of such data stored by a client.
An attacker able to "inject" availability information into a calendar An attacker able to "inject" availability information into a calendar
user's calendar data could ensure that the user never appears free user's calendar data could ensure that the user never appears free
for meetings, or appears free at inappropriate times. Calendar for meetings, or appears free at inappropriate times. Calendar
systems MUST ensure that availability information for a calendar user systems MUST ensure that availability information for a calendar user
can only be modified by authorized users. can only be modified by authorized users.
Security considerations in [RFC5545], [RFC5546], [RFC4791], Security considerations in [RFC5545], [RFC5546], [RFC4791],
[RFC6638], and [RFC7809] MUST also be adhered to. [RFC6638], and [RFC7809] MUST also be adhered to.
9. Privacy Considerations 9. Privacy Considerations
Free-busy and availability information can be used by attackers to Free-busy and availability information can be used by attackers to
infer the whereabouts or overall level of "activity" of the infer the whereabouts or overall level of "activity" of the
corresponding calendar user. Any calendar system that allows a user corresponding calendar user. Any calendar system that allows a user
to expose their free-busy and availability information MUST limit to expose their free-busy and availability information MUST limit
access to that information to only authorized users. access to that information to only authorized users.
When "VAVAILABILITY" components are sent to or shared with other When "VAVAILABILITY" components are sent to or shared with other
calendar users, care has to be taken to not expose more information calendar users, care has to be taken not to expose more information
than is needed by each recipient. In particular, user specified than is needed by each recipient. For example, a business owner will
property values such as "SUMMARY", "LOCATION" and "DESCRIPTION" likely not want their customers to know where they might be or what
properties might need to be removed from the "VAVAILABILITY" they might be doing, but family members might be willing to expose
components exposed to other calendar users. For example, family such information to each other. Thus, calendaring systems allowing
members might be willing to expose their location to each other, but "VAVAILABILITY" components to be sent or shared to other calendar
a business owner will likely not want to do that with their users, MUST provide a way for non-essential properties to be removed
customers. (e.g., "SUMMARY", "LOCATION", and "DESCRIPTION").
iCalendar "VFREEBUSY" information generated from "VAVAILABILITY" iCalendar "VFREEBUSY" information generated from "VAVAILABILITY"
components MUST NOT include information other than busy or free time components MUST NOT include information other than busy or free time
periods. In particular, user specified property values such as periods. In particular, user specified property values such as
"SUMMARY", "LOCATION" and "DESCRIPTION" MUST NOT be copied into the "SUMMARY", "LOCATION" and "DESCRIPTION" MUST NOT be copied into the
free-busy result data. free-busy result data.
Privacy considerations in [RFC5545], [RFC5546], [RFC4791], [RFC6638], Privacy considerations in [RFC5545], [RFC5546], [RFC4791], [RFC6638],
and [RFC7809] MUST also be adhered to. and [RFC7809] MUST also be adhered to.
skipping to change at page 21, line 20 skipping to change at page 21, line 20
[RFC6638] Daboo, C. and B. Desruisseaux, "Scheduling Extensions to [RFC6638] Daboo, C. and B. Desruisseaux, "Scheduling Extensions to
CalDAV", RFC 6638, DOI 10.17487/RFC6638, June 2012, CalDAV", RFC 6638, DOI 10.17487/RFC6638, June 2012,
<http://www.rfc-editor.org/info/rfc6638>. <http://www.rfc-editor.org/info/rfc6638>.
[RFC7809] Daboo, C., "Calendaring Extensions to WebDAV (CalDAV): [RFC7809] Daboo, C., "Calendaring Extensions to WebDAV (CalDAV):
Time Zones by Reference", RFC 7809, DOI 10.17487/RFC7809, Time Zones by Reference", RFC 7809, DOI 10.17487/RFC7809,
March 2016, <http://www.rfc-editor.org/info/rfc7809>. March 2016, <http://www.rfc-editor.org/info/rfc7809>.
Appendix A. Example Calendar #1 Appendix A. Example Calendar #1
iCalendar object
BEGIN:VCALENDAR BEGIN:VCALENDAR
CALSCALE:GREGORIAN CALSCALE:GREGORIAN
PRODID:-//example.com//iCalendar 2.0//EN PRODID:-//example.com//iCalendar 2.0//EN
VERSION:2.0 VERSION:2.0
BEGIN:VEVENT BEGIN:VEVENT
DTSTAMP:20111113T044111Z DTSTAMP:20111113T044111Z
DTSTART;TZID=America/Montreal:20111106T120000 DTSTART;TZID=America/Montreal:20111106T120000
DURATION:PT1H DURATION:PT2H
SUMMARY:Meeting SUMMARY:Meeting
UID:60A48841ECB90F3F215FE3D2@example.com UID:768CB0C2-8642-43F7-A6C4-F8BB04B829B4
END:VEVENT END:VEVENT
BEGIN:VAVAILABILITY BEGIN:VAVAILABILITY
UID:vavail-1@example.com UID:452DFCA7-3203-4A3D-9A9A-99753A383B41
DTSTAMP:20111005T133225Z DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Montreal:20111002T000000 DTSTART;TZID=America/Montreal:20111002T000000
BEGIN:AVAILABLE BEGIN:AVAILABLE
UID:avail-1-A@example.com UID:466D5C68-5C4A-4078-AF5D-9C55EA9145D7
SUMMARY:Monday to Friday from 8:00 to 18:00 SUMMARY:Monday to Friday from 8:00 to 18:00
DTSTART;TZID=America/Montreal:20111002T080000 DTSTART;TZID=America/Montreal:20111002T080000
DTEND;TZID=America/Montreal:20111002T180000 DTEND;TZID=America/Montreal:20111002T180000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
END:AVAILABLE END:AVAILABLE
END:VAVAILABILITY END:VAVAILABILITY
END:VCALENDAR END:VCALENDAR
Appendix B. Change History (To be removed by RFC Editor before Appendix B. Example Calendar #2
BEGIN:VCALENDAR
CALSCALE:GREGORIAN
PRODID:-//example.com//iCalendar 2.0//EN
VERSION:2.0
BEGIN:VEVENT
DTSTAMP:20111113T044111Z
DTSTART;TZID=America/Denver:20111106T120000
DURATION:PT2H
SUMMARY:Lunch meeting in Denver
UID:2346C09A-42BF-439E-916C-FC83AF869171
END:VEVENT
BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com
UID:627A87FA-E5F1-43C0-B3B1-567DA10F2A83
DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Montreal:20111002T000000
BEGIN:AVAILABLE
UID:A833E850-892B-43F6-98B6-C15A6BFC5D27
SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Montreal:20111002T080000
DTEND;TZID=America/Montreal:20111002T180000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
LOCATION:Montreal
END:AVAILABLE
END:VAVAILABILITY
BEGIN:VAVAILABILITY
ORGANIZER:mailto:bernard@example.com
UID:F01411E3-38B8-4490-8A1F-0CCEC57A0943
DTSTAMP:20111005T133225Z
DTSTART;TZID=America/Denver:20111023T000000
DTEND;TZID=America/Denver:20111030T000000
PRIORITY:1
BEGIN:AVAILABLE
UID:A35AA091-3846-48ED-96F6-881E8A0D0A93
SUMMARY:Monday to Friday from 9:00 to 17:00
DTSTART;TZID=America/Denver:20111023T080000
DTEND;TZID=America/Denver:20111023T180000
RRULE:FREQ=WEEKLY;BYDAY=MO,TU,WE,TH,FR
LOCATION:Denver
END:AVAILABLE
END:VAVAILABILITY
END:VCALENDAR
Appendix C. Change History (To be removed by RFC Editor before
publication) publication)
Changes in draft-ietf-calext-availability-04:
1. [OPSDIR] Mark as updating 5545, 4791, 6638.
2. [OPSDIR] Moved alternative example to Appendix.
3. [OPSDIR] Use different symbols for different nested list levels
in Section 5.
4. [OPSDIR] Added table to illustrate spacing out priority values.
5. [OPSDIR] Editorial fixes.
6. [IESG] changed to MUST for server applying limits.
7. [IESG] Editorial fixes.
8. Changed UID values to UUIDs.
9. Abstract tweak to spell out CalDAV.
Changes in draft-ietf-calext-availability-03: Changes in draft-ietf-calext-availability-03:
1. [EXPERT] Make 7809 reference more authoritative. 1. [EXPERT] Make 7809 reference more authoritative.
2. [EXPERT] Add reference to privacy section when describing use of 2. [EXPERT] Add reference to privacy section when describing use of
LOCATION. LOCATION.
3. [EXPERT] Added more text to privacy section to cover published 3. [EXPERT] Added more text to privacy section to cover published
or iTIP-messaged VAVAILABILITY components. or iTIP-messaged VAVAILABILITY components.
 End of changes. 56 change blocks. 
135 lines changed or deleted 208 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/