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          13                                                            
          Network Working Group                   Steve Mansour/Netscape
          Internet Draft                                      Doug Royer
          <draft-ietf-calsch-cap-04.txt>           George Babics/Steltor
                                                           Paul Hill/MIT
                         Calendar Access Protocol (CAP)
          
          
          Status of this Memo
          
          This memo is an Internet-Draft and is in full conformance with
          all provisions of Section 10 of RFC2026.
          
          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."
          
          The list of current Internet-Drafts can be accessed at
          http://www.ietf.org/ietf/1id-abstracts.txt .
          
          The list of Internet-Draft Shadow Directories can be accessed
          at http://www.ietf.org/shadow.html.
          
          Distribution of this document is unlimited.
          
          
          Copyright Statement
          
          Copyright (C) The Internet Society 2000. All Rights Reserved.
          
          
          Abstract
          
          The Calendar Access Protocol (CAP) is an Internet protocol
          that permits a Calendar User (CU) to utilize a Calendar User
          Agent (CUA) to access an [iCAL] based Calendar Store (CS).
          This memo defines the CAP specification.
          
          The CAP definition is based on requirements identified by the
          Internet Engineering Task Force (IETF) Calendaring and
          Scheduling (CALSCH) Working Group. More information about the
          IETF CALSCH Working Group activities can be found on the IMC
          web site at http://www.imc.org/ietf-calendar, and at the IETF
          web site at http://www.ietf.org/html.charters/calsch-
          charter.html. Refer to the references within this memo for
          further information on how to access these various documents.
          
          
          
          
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          Table Of Contents
          1 Introduction.............................................4
           1.1  Formatting Conventions...............................4
           1.2  Related Documents....................................5
           1.3  Definitions..........................................5
          2 CAP Design..............................................12
           2.1  System Model........................................12
           2.2  Calendar Store Object Model.........................13
           2.3  Protocol Model......................................15
           2.4  Security Model......................................16
            2.4.1 Authentication, Credentials, and Identity........17
            2.4.2 Calendar User and UPNs...........................18
            2.4.3 User Groups......................................21
            2.4.4 Access Rights - Summary..........................22
            2.4.5 Inheritance......................................23
            2.4.6 CAP Session Identity.............................24
           2.5  Roles...............................................25
           2.6  Calendar Addresses..................................25
           2.7  Extensions to iCalendar.............................26
           2.8  Relationship of RFC 2446 (ITIP) to CAP..............27
          3 State Diagram...........................................29
          4 Protocol Framework......................................30
           4.1  CAP Application Layer...............................30
           4.2  CAP Transfer Protocol...............................31
           4.3  Pipelining of Commands..............................32
           4.4  Auto-logout Timer...................................32
           4.5  Bounded Latency.....................................32
           4.6  Data Elements.......................................32
          5 Formal Command Syntax...................................32
           5.1  Searching and Filtering.............................32
            5.1.1 Grammar For Search Mechanism.....................33
            5.1.2 SQL-MIN notes....................................34
            5.1.3 SQL-92 notes.....................................35
            5.1.4 Example, Query by UID............................35
            5.1.5 Query by Date-Time range.........................35
            5.1.6 Query for all Non-Booked Entries.................36
            5.1.7 Query with Subset of Properties by Date/Time.....36
            5.1.8 Components With Alarms In A Range................36
          6 Access Rights...........................................37
           6.1  VCAR Inheritance....................................37
           6.2  Access Control and NOCONFLICT.......................37
          7 Commands and Responses..................................38
           7.1  Transfer Protocol Commands..........................38
            7.1.1 Initial Connection...............................38
            7.1.2 ABORT Command....................................39
            7.1.3 AUTHENTICATE Command.............................39
            7.1.4 CALIDEXPAND Command..............................43
            7.1.5 CAPABILITY Command...............................45
            7.1.6 CONTINUE Command.................................47
          
          
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            7.1.7 DISCONNECT Command...............................48
            7.1.8 SENDDATA Command.................................49
           7.2  Application Protocol Commands.......................52
            7.2.1 Calendaring Commands.............................52
            7.2.2 Scheduling Commands..............................84
            7.2.3 iTIP Examples....................................89
          8 Response Codes..........................................96
          9 Examples................................................98
           9.1  Authentication Examples.............................98
            9.1.1 Login Using Kerberos V4..........................98
            9.1.2 Error Scenarios..................................99
           9.2  Read Examples......................................100
            9.2.1 Read From Multiple Calendars....................101
            9.2.2 Timeouts........................................102
            9.2.3 Using Parent and Children Properties............103
            9.2.4 Query VEVENT.DTSTART and VALARM.DTSTART.........103
          10  Implementation Issues................................103
          11  Properties...........................................104
           11.1  Calendar Store Properties........................104
           11.2  Calendar Properties..............................105
          12  Security Considerations..............................107
          13  CAP Item Registration................................107
           13.1  Registration of New and Modified CAP Entities....107
           13.2  Registration of New Entities.....................107
            13.2.1  Define the Item...............................108
            13.2.2  Post the item definition......................109
            13.2.3  Allow a comment period........................109
            13.2.4  Submit the proposal for approval..............109
           13.3  Property Change Control..........................109
          14  IANA Considerations..................................110
          15  Acknowledgments......................................110
          16  Bibliography.........................................111
          17  Author's Address.....................................112
          18  Full Copyright Statement.............................112
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
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          1  Introduction
          
          This document specifies how a Calendar User Agent (CUA)
          interacts with a Calendar Store (CS) to manage calendar
          information. In particular, it specifies how to query, create,
          modify, and delete iCalendar components (e.g., events, to-dos,
          or daily journal entries). It further specifies how to search
          for available busy time information.
          
          This protocol is based on request/response form of data units,
          sent from a client CUA to a calendar server. The protocol data
          units leverage the standard iCalendar format [iCAL] for
          conveying CS related information.
          
          1.1 Formatting Conventions
          
          The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
          NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY" and
          "OPTIONAL" in this document are to be interpreted as described
          in [RFC2119].
          
          Calendaring and scheduling roles are referred to in quoted-
          strings of text with the first character of each word in upper
          case. For example, "Organizer" refers to a role of a "Calendar
          User" (CU) within the protocol defined by this memo. Calendar
          components defined by [iCAL] are referred to with capitalized,
          quoted-strings of text. All calendar components start with the
          letter "V". For example, "VEVENT" refers to the event calendar
          component, "VTODO" refers to the to-do calendar component and
          "VJOURNAL" refers to the daily journal calendar component.
          Calendar access methods defined by this memo, as well as
          scheduling methods defined by [iTIP], are referred to with
          capitalized, quoted-strings of text. For example, "CREATE"
          refers to the method for creating a calendar component on a
          calendar, "READ" refers to the method for reading calendar
          components.
          
          Properties defined by this memo are referred to with
          capitalized, quoted-strings of text, followed by the word
          "property". For example, "ATTENDEE" property refers to the
          iCalendar property used to convey the calendar address of a
          "Calendar User". Property parameters defined by this memo are
          referred to with lower case, quoted-strings of text, followed
          by the word "parameter". For example, "value" parameter refers
          to the iCalendar property parameter used to override the
          default data type for a property value. Enumerated values
          defined by this memo are referred to with capitalized text,
          either alone or followed by the word "value".
          
          
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          In tables, the quoted-string text is specified without quotes
          in order to minimize the table length.
          
          1.2 Related Documents
          
          Implementers will need to be familiar with several other memos
          that, along with this one, describe the Internet calendaring
          and scheduling standards. These documents are:
          
          [iCAL] (RFC2445) which specifies the objects, data types,
          properties and property parameters used in the protocols,
          along with the methods for representing and encoding them,
          
          [iTIP] (RFC2446) which specifies an interoperability protocol
          for scheduling between different implementations. The related
          documents are:
          
          [iMIP] (RFC2447) which specifies an Internet email binding for
          [iTIP].
          
          [IMPL] (draft/rfc...) which is a guide to implementers and
          describes the elements of a calendaring system, how they
          interact with each other, how they interact with end users,
          and how the standards and protocols are used.
          
          This memo does not attempt to repeat the specification of
          concepts or definitions from these other memos. Where
          possible, references are made to the memo that provides for
          the specification of these concepts or definitions.
          
          1.3 Definitions
          
          Authentication ID (AuthID)
          
                  A tuple of username, realm, and authentication
                  method, used by the Calendar Service internally to
                  identify a successfully authenticated CAP session.
          
          Booked
          
                  A entry in a calendar has one of two conceptual
                  states. It is scheduled or it is booked.  A scheduled
                  entry has been stored in the calendar store but has
                  not been acted on by a calendar user or calendar user
                  agent. A booked appointment is an entry that has had
                  its state changed from one of the [iTIP] scheduling
                  methods to a CAP method of CREATE by a calendar user
          
          
          
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                  or calendar user agent which resulted in decision to
                  keep the entry in the calendar store.
          
          Calendar
          
                  A collection of logically related objects or entities
                  each of which may be associated with a calendar date
                  and possibly time of day. These entities can include
                  other calendar properties or calendar components.In
                  addition, a calendar might be hierarchically related
                  to other sub-calendars. A calendar is identified by
                  its unique calendar identifier. The [iCAL] defines
                  calendar properties, calendar components and
                  component properties that make up the content of a
                  calendar.
          
          Calendar Access Protocol (CAP)
          
                  The standard Internet protocol that permits a
                  Calendar User Agent to access and manipulate a
                  calendar residing on a Calendar Store.
          
          
          Calendar Access Rights (CAR)
          
                  The mechanism for specifying the CAP operations
                  ("ACTIONS") that a particular calendar user ("UPN")
                  are granted or denied permission to perform on a
                  given calendar item ("OBJECT"). The calendar access
                  rights are specified with the "VCAR" calendar
                  components within a CS and calendar.
          
          
          Calendar Collection
          
                  A collection of Calendars, Resource Calendars, and/or
                  other Calendar Collections.  These collections are
                  expanded by the CS and may reside either locally or
                  in an external database or directory.  The calendars
                  in the collection may be fixed or dynamic over time.
          
          
          Calendar Component
          
                  An item within a calendar. Some types of calendar
                  components include events, to-dos, journals, alarms,
                  time zones and freebusy data. A calendar component
                  consists of component properties and possibly other
          
          
          
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                  sub-components. For example, an event may contain an
                  alarm component.
          
          
          Calendar Component Properties
          
                  An attribute of a particular calendar component. Some
                  calendar component properties are applicable to
                  different types of calendar components. For example,
                  DTSTART is applicable to VEVENT, VTODO, VJOURNAL
                  calendar components. Other calendar components are
                  applicable only to an individual type of calendar
                  component. For example, TZURL is only applicable to
                  VTIMEZONE calendar components.
          
          
          Calendar Identifier (CalID)
          
                  A globally unique identifier associated with a
                  calendar. Calendars reside within a CS. See Qualified
                  Calendar Identifier and Relative Calendar Identifier.
          
          
          Calendar Policy
          
                  A CAP operational restriction on the access or
                  manipulation of a calendar. For example, "events MUST
                  be scheduled in unit intervals of one hour".
          
          
          Calendar Properties
          
                  An attribute of a calendar. The attribute applies to
                  the calendar, as a whole. For example, CALSCALE
                  specifies the calendar scale (e.g., GREGORIAN) for
                  the whole calendar.
          
          
          Calendar Service
          
                  An implementation of a Calendar Store that manages
                  one or more calendars.
          
          
          Calendar Store (CS)
          
                  The data and service model definition for a Calendar
                  Service.
          
          
          
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          Calendar Store Identifier (CSID)
          
                  The globally unique identifier for an individual CS.
                  A CSID consists of the host and port portions of a
                  "Common Internet Scheme Syntax" part of a URL, as
                  defined by [URL].
          
          
          Calendar Store Components
          
                  Components maintained in a CS specify a grouping of
                  calendar store-wide information. Calendar store
                  components can be accessed using CAP.
          
          
          Calendar Store Properties
          
                  Properties maintained in a Calendar Store calendar
                  store-wide information. Calendar store properties can
                  be accessed using CAP.
          
          
          Calendar User (CU)
          
                  An entity (often biological) that uses a calendaring
                  system.
          
          
          Calendar User Agent (CUA)
          
                  The CUA is the client application that a CU or UG
                  utilizes to access and manipulate a calendar.
          
          
          Calendaring and Scheduling System
          
                  The computer sub-system that provides the services
                  for accessing, manipulating calendars and scheduling
                  calendar components.
          
          
          CAP Session
          
                  An open communication channel between a CAP CUA and a
                  CAP CS.
          
          
          Connected Mode
          
          
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                  A mobile computing mode where the CUA is directly
                  connected to the CS.
          
          
          Delegate
          
                  Is a calendar user (sometimes called the delegatee)
                  who has been assigned participation in a scheduled
                  calendar component (e.g., VEVENT) by one of the
                  attendees in the scheduled calendar component
                  (sometimes called the delegator). An example of a
                  delegate is a team member told to go to a particular
                  meeting.
          
          
          Designate
          
                  Is a calendar user who is authorized to act on behalf
                  of another calendar user. An example of a designate
                  is an assistant.
          
          
          Disconnected Mode
          
                  A mobile computing mode where a CUA can be
                  disconnected from a CS. When the CUA is disconnected,
                  it is in the disconnected mode.
          
          
          Fan Out
          
                  The calendaring and scheduling process by which a
                  calendar operation on one calendar is also performed
                  on every other calendar specified in the operation.
                  This may include the calendar associated with TARGET
                  calendar property.
          
          
          Hierarchical Calendars
          
                  A CS feature where a calendar have a hierarchical
                  relationship with another calendar in the CS. The
                  top-most calendar in the hierarchical relationship
                  has the CS as its parent. There may be multiple top-
                  most calendars in a given CS. Within a given
                  hierarchical relationship, all sub-calendars have a
                  calendar with a "parent" topographical relationship.
                  In addition, sub-calendars may have a relationship
          
          
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                  with another calendar that has a "child"
                  topographical relationship. In addition, a calendar
                  may have a relationship such that one or more
                  calendars have a "sibling" topographical relationship
                  with the calendar. The hierarchical calendar feature
                  is not a storage relationship of the calendars within
                  the CS. Instead it is a feature that relates access
                  control rights to calendar content between different
                  calendars in the CS.  The hierarchical relationship
                  of a calendar is specified in the "PARENT" and
                  "CHILDREN" calendar properties.
          
          
          High Bandwidth Connection
          
                  A communications connection supporting high transfer
                  rates; transfer rates commonly found within a LAN.
          
          
          Local Store
          
                  A CS which is on the same platform as the CUA.
          
          
          Low Bandwidth Connection
          
                  A communications connection supporting slow transfer
                  rates; transfer rates commonly found in remote access
                  technology.
          
          
          Overlapped Booking
          
                  A policy which indicates whether or not OPAQUE events
                  can overlap one another. When the policy is applied
                  to a calendar it indicates whether or not any OPAQUE
                  events in the calendar can overlap. When applied to
                  an individual event, it indicates whether or not it
                  can be overlapped by any other OPAQUE event.
          
          
          Owner
          
                  One or more CUs or UGs that have "OWNER" calendar
                  access rights for a calendar. The owner is specified
                  in the "OWNER" calendar property.
          
          
          Qualified Calendar Identifier (Qualified CalID)
          
          
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                  A CalID where both the <scheme> and <csid> are
                  present.
          
          
          Realm
          
                  A collection of calendar user accounts, identified by
                  a string.  The name of the realm is only used in
                  UPNs. In order to avoid namespace conflict, the realm
                  SHOULD be postfixed with an appropriate DNS domain
                  name. (eg: the foobar realm could be called
                  foobar.example.com).
          
          
          Relative Calendar Identifier (Relative CalID)
          
                  An identifier for an individual calendar in a
                  calendar store. It is unique within a calendar store.
                  It is recommended to be globally unique. A Relative
                  CalID consists of the portion of the "scheme part" of
                  a Qualified CalID following the Calendar Store
                  Identifier. This is the same as the "URL path" of the
                  "Common Internet Scheme Syntax" portion of a URL, as
                  defined by [URL].
          
          
          Remote Store
          
                  A CS which is not on the same platform as the CUA.
          
          
          Resource Calendar (RC)
          
                  A non-human Calendar, associated with an
                  organizational resource. There is no syntactic
                  difference between an RC and a Calendar.
          
          
          Session Identity
          
                  A UPN associated with a CAP session. A session gains
                  an identity after successful authentication. The
                  identity is used in combination with CAR to determine
                  access to data in the CS.
          
          
          Sub-calendars
          
          
          
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                  Calendars that have a "child" hierarchical
                  relationship with another calendar, its "parent".
          
          
          User Group (UG)
          
                  A collection of Calendar Users and/or User Groups.
                  These groups are expanded by the CS and may reside
                  either locally or in an external database or
                  directory.  The group membership may be fixed or
                  dynamic over time.
          
          
          User Name
          
                  A name which denotes a Calendar User within a realm.
                  This is part of a UPN.
          
          
          User Principal Name (UPN)
          
                  An identifier that denotes a unique CU. A UPN is an
                  RFC 822 compliant email address, with exceptions
                  listed below, and in most cases it is deliverable to
                  the CU. In some cases it is identical to the CU's
                  well known email address.  A CU's UPN MUST never be
                  deliverable to a different person. It consists of a
                  realm in the form of a valid, and unique, DNS domain
                  name and a unique username. In it's simplest form it
                  looks like "user@example.com".
          
                  In certain cases a UPN will not be RFC 822 compliant.
                  When anonymous authentication is used, or anonymous
                  authorization is being defined, the special UPN "@"
                  will be used. When authentication must be used, but
                  unique identity must be obscured, a UPN of the form
                  @DNS-domain-name may be used. For example,
                  "@example.com". Usage of these special cases is
                  further discussed in the authentication and
                  authorization sections of this document.
          
          
          2  CAP Design
          
          2.1 System Model
          
          The system model describes the high level components of a
          calendar system and how they interact with each other.
          
          
          
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          CAP is used by a "Calendar User Agent" (CUA) to send commands
          to and receive responses from a "Calendar Service" (CS). The
          CUA prepares a [MIME] encapsulated iCalendar object containing
          a command, sends it to the CS, and receives a [MIME]
          encapsulated iCalendar object as a response. There are two
          distinct protocols in operation to accomplish this exchange.
          The Transfer Protocol is used to move these encapsulations
          between a CUA and a CS. The Application Protocol defines the
          content and semantics of the iCalendar objects sent between
          the CUA and the CS. This document defines both the Transfer
          Protocol and the Application Protocol.
          
          In the diagram below, a user uses CUA1 to communicate with CS1
          using CAP. The CUA must authenticate the Calendar User (CU) so
          that access to calendars on CS1 can be controlled. The CUA can
          then view, create, edit, and delete calendars, calendar
          properties, and calendar components subject to the access
          rights.
          
          CAP servers support fanout. Fanout allows a CUA to communicate
          with a single CS to perform scheduling operations with
          calendars on multiple CSs. That is, a CU can book or schedule
          events (or to-dos) on or read events (or to-dos) from
          calendars on other calendar stores. To accomplish this, a CAP
          server takes on these roles:
          
               * CS1 MAY play the role of a CUA and use CAP to access
                  CS2;
               * CS1 MUST be able play the role of a CUA and use [iMIP]
                  to interoperate with other CUAs.
          
                    +-----+          +-----+
                    |     |   CAP    |     |   CAP
          CUA1------| CS1 |----------| CS2 |--------- CUA2
                    |     |          |     |           A
                    |     |          |     |           |
                    |     |          |     |           |
                    +-----+          +-----+           |
                      |        IMIP                    |
                      +--------------------------------+
          
          
          Note that the fanout feature in CAP is a convenience to the
          CUA. It is perfectly valid for the CUA to assume the
          responsibility for fanout if it wishes. That is, [iMIP]
          messages could also be sent from CUA1 to CUA2.
          
          2.2 Calendar Store Object Model
          
          
          
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          The conceptual model for a calendar store is shown below. The
          calendar store contains calendars, VTIMEZONEs, VCARs, and
          calendar store properties.
          
          Calendars contain VEVENTs, VTODOs, VJOURNALs, VALARMs, VCARs,
          and calendar properties. Calendars may also contain other
          calendars.
          
          Calendar Store
            |
            +-- VCARs
            +-- Properties
            +-- VCARs
            +-- VTIMEZONEs
            +-- VCALENDARs
                  |
                  +--VEVENTs
                       +--VALARMs
                  +--VTODOs
                       +--VALARMs
                  +--VJOURNALs
                  +--VCARs
                  +--Properties
                  +--VTIMEZONEs
                  +--VSCHEDULE
                  +--Calendar
                       |
                       +--VEVENTs
                            +--VALARMs
                       +--VTODOs
                            +--VALARMs
                       +--VJOURNALs
                       +--VALARMs
                       +--VCARs
                       +--Properties
                       +--VTIMEZONEs
                       +--VSCHEDULE
                       +--Calendar
                            |
                           ...
          
          Calendars within a Calendar Store are identified by their
          Relative CALID.
          
          In this model, VSCHEDULE is a queue of scheduling messages
          that have not yet been applied to the calendar. Items in
          VSCHEDULE are discussed in more detail below.
          
          
          
          
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          2.3 Protocol Model
          
          A generic transfer-layer, Calendar Server Transfer Protocol
          (CSTP), is used to move data objects between a CUA and the CS.
          CSTP commands are listed below and their usage and semantics
          are defined in section 7.1 of this document.
          
          
          CSTP Commands
          -----------------------------------------------------------
          Command         Description
          -----------------------------------------------------------
          ABORT           Stop a command. Perhaps because its latency
                          time has been exceeded.
          AUTHENTICATE    Authenticate a UPN.
          CONTINUE        Continue the execution of a command whose
                          Latency time has been exceeded.
          IDENTIFY        Set a new identity for calendar access.
          DISCONNECT      Terminate a connection with the server.
          SENDDATA        Send a data object [MIME] encapsulated
                          iCalendar.
          STARTTLS        Negotiate transport level security using
                          [TLS].
          -----------------------------------------------------------
          
          
          Application-level commands are used to manipulate data on the
          calendar store. They are listed below and discussed in detail
          in section 7.2.
          
          
          CAP Calendaring Commands
          -----------------------------------------------------------
          Command          Description
          -----------------------------------------------------------
          CREATE           Create a new calendar or component.
          DELETE           Delete a calendar or component.
          GENERATEUID      Generate one or more unique ids.
          MODIFY           Change a calendar or component.
          MOVE             Move a calendar.
          READ             Read a calendar properties or components.
          -----------------------------------------------------------
          
          
          CAP Scheduling Commands
          (As defined in [iTIP])
          -----------------------------------------------------------
          Command        Description
          -----------------------------------------------------------
          
          
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          PUBLISH        Publish a calendar entry to one or more
                         calendars.
          REQUEST        Schedule a calendar entry with one or more
                         calendars.
          REPLY          Response to a scheduling request.
          ADD            Add one or more instances to an existing
                         calendar entry.
          CANCEL         Cancel one or more instances to an existing
                         calendar entry.
          REFRESH        A request for the latest version of a
                         calendar entry.
          COUNTER        A request for a change(a counter-proposal)to
                         a calendar entry.
          DECLINECOUNTER Decline a counter proposal.
          -----------------------------------------------------------
          
          
          2.4 Security Model
          
          Authentication to the CS will be performed using [SASL].
          
          As noted in the CAP system model section, a variety of
          connectivity scenarios are possible. This complicates the
          security model considerably, and a thorough familiarity with
          the concepts is required to ensure interoperability.
          
          Basic threats to a Calendaring and Scheduling System include:
          
          (1) Unauthorized access to data via data-fetching operations,
          
          (2) Unauthorized access to reusable client authentication
              information by monitoring others' access,
          
          (3) Unauthorized access to data by monitoring others' access,
          
          (4) Unauthorized modification of data,
          
          (5) Unauthorized or excessive use of resources (denial of
              service), and
          
          (6) Spoofing of CS: Tricking a client into believing that
              information came     from the CS when in fact it did
              not, either by modifying data in transit or
              misdirecting the client's connection.
          
          Threats (1), (4), (5) and (6) are due to hostile clients.
          Threats (2), and (3) are due to hostile agents on the path
          between client and server, or posing as a server.
          
          
          
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          CAP can be protected with the following security mechanisms:
          
          (1) Client authentication by means of the SASL mechanism
              set, possibly backed by the TLS credentials exchange
              mechanism,
          
          (2) Client authorization by means of access control based
              on the requestor's authenticated identity,
          
          (3) Data integrity protection by means of the TLS protocol
              or data integrity SASL mechanisms,
          
          (4) Protection against snooping by means of the TLS
              protocol or data encrypting SASL mechanisms,
          
          (5) Resource limitation by means of administrative limits
              on service controls, and
          
          (6) Server authentication by means of the TLS protocol or
              SASL mechanism.
          
          Imposition of access controls (authorizations) is done by
          means of VCARs, an overview is provided in section <fwd ref>,
          and a detailed syntax is provided in section <fwd ref>.
          Authentication is explained in detail in section <fwd ref>.
          
          
          2.4.1  Authentication, Credentials, and Identity
          
          Generically, authentication credentials are the evidence
          supplied by one party to another, asserting the identity of
          the supplying party (e.g. a user) who is attempting to
          establish an association with the other party (typically a
          server). Authentication is the process of generating,
          transmitting, and verifying these credentials and thus the
          identity they assert. An authentication identity is the name
          presented in a credential.
          
          There are many forms of authentication credentials. The form
          used depends upon the particular authentication mechanism
          negotiated by the parties. For example: X.509 certificates,
          Kerberos tickets, simple identity and password pairs. Note
          that an authentication mechanism may constrain the form of
          authentication identities used with it.
          
          SASL only provides a protocol to negotiate a mutually
          acceptable authentication mechanism. SASL itself does not
          constrain or dictate the form of the authentication identities
          used to perform the authentication.
          
          
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          2.4.2  Calendar User and UPNs
          
          A Calendar User(CU) is an entity that can be authenticated. It
          is represented in CAP as a UPN. A UPN is the owner of a
          calendar and the subject of access rights. The UPN
          representation is independent of the authentication mechanism
          used during a particular CUA/CS interaction. This is because
          UPNs are used within VCARs. If the UPN were dependent on the
          authentication mechanism, a VCAR could not be consistently
          evaluated. A CU may use one mechanism while using one CUA but
          the same CU may use a different authentication mechanism when
          using a different CUA, or while connecting from a different
          location.
          
          The user may also have multiple UPNs for various purposes.
          
          Note that the immutability of the user's UPN may be achieved
          by using SASL's authorization identity feature. (The
          transmitted authorization identity may be different than the
          identity in the client's authentication credentials.) [SASL,
          section 3] This also permits a CU to authenticate using their
          own credentials, yet request the access privileges of the
          identity for which they are proxying SASL. Also, the form of
          authentication identity supplied by a service like TLS may not
          correspond to the UPNs used to express a server's access
          control policy, requiring a server-specific mapping to be
          done. The method by which a server composes and validates an
          authorization identity from the authentication credentials
          supplied by a client is implementation-specific.
          
          For Calendaring and Scheduling Systems that are integrated
          with a directory system, the CS MUST support the ability to
          configure which schema attribute stores the UPN. The CS MAY
          allow one or more attributes to be searched for the UPN.
          
          
          2.4.2.1   UPNs and Certificates
          
          When using X.509 certificates for purposes of CAP
          authentication, the UPN should appear in the certificate.
          Unfortunately there is no single correct guideline for which
          field should contain the UPN.
          
          From RFC-2459, section 4.1.2.6 (Subject):
          
                  If subject naming information is present only in the
                  subjectAlt-Name extension (e.g., a key bound only to
                  an email address or URI), then the subject name MUST
          
          
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                  be an empty sequence and the subjectAltName extension
                  MUST be critical.
          
                  Implementations of this specification MAY use these
                  comparison rules to process unfamiliar attribute
                  types (i.e., for name chaining). This allows
                  implementations to process certificates with
                  unfamiliar attributes in the subject name.
          
                  In addition, legacy implementations exist where an
                  RFC 822 name is embedded in the subject distinguished
                  name as an EmailAddress attribute.  The attribute
                  value for EmailAddress is of type IA5String to permit
                  inclusion of the character '@', which is not part of
                  the PrintableString character set. EmailAddress
                  attribute values are not case sensitive (e.g.,
                  "fanfeedback@redsox.com" is the same as
                  "FANFEEDBACK@REDSOX.COM").
          
                  Conforming implementations generating new
                  certificates with electronic mail addresses MUST use
                  the rfc822Name in the subject alternative name field
                  (see sec. 4.2.1.7 [of RFC 2459]) to describe such
                  identities. Simultaneous inclusion of the
                  EmailAddress attribute in the subject distinguished
                  name to support legacy implementations is deprecated
                  but permitted.
          
          
          Since no single method of including the UPN in the certificate
          will work in all cases, CAP implementations MUST support the
          ability to configure what the mapping will be by the CS
          administrator. Implementations MAY support multiple mapping
          definitions, for example, the UPN may be found in either the
          subject alternative name field, or the UPN may be embedded in
          the subject distinguished name as an EmailAddress attribute.
          
          
          Note: If a CS or CUA is validating data received via iMIP, if
          the "ORGANIZER" or "ATTENDEE" property said (e.g.)
          "ATTENDEE;CN=Joe Random User:juser@example.com" then the email
          address should be checked against the UPN, and the CN should
          also be checked. This is so the "ATTENDEE" property couldn't
          be munged to something misleading like "ATTENDEE;CN=Joe Rictus
          User:juser@example.com" and have it pass validation. This
          validation will also defeat other attempts at  confusion.
          2.4.2.2   Anonymous Users and Authentication
          
          
          
          
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          Anonymous access is often desirable. For example an
          organization may publish calendar information that does not
          require any access control for viewing or login. Conversely, a
          user may wish to view unrestricted calendar information
          without revealing their identity.
          
          CAP implementations MUST support anonymous authentication, as
          defined in section <fwd ref 7.1.3>.
          
          CAP implementations MAY support anonymous authentication with
          TLS, as defined in section <fwd ref 7.1.3.2>.
          2.4.2.3   Required Security Mechanisms
          
          The following implementation conformance requirements are in
          place:
          
          (1) For a read-only, public CS, anonymous authentication,
          described in section <fwd ref 7.1.3.1>, can be used.
          
          (2) Implementations providing password-based authenticated
          access MUST support authentication using Digest, as described
          in section <fwd ref>.  This provides client authentication
          with protection against passive eavesdropping attacks, but
          does not provide protection against active intermediary
          attacks.
          
          (3) For a CS needing session protection and authentication,
          the Start TLS extended operation, and either the simple
          authentication choice or the SASL EXTERNAL mechanism, are to
          be used together.  Implementations SHOULD support
          authentication with a password as described in section <fwd
          ref>, and SHOULD support authentication with a certificate as
          described in section <fwd ref>.  Together, these can provide
          integrity and disclosure protection of transmitted data, and
          authentication of client and server, including protection
          against active intermediary attacks.
          2.4.2.4   TLS Ciphersuites
          
          The following ciphersuites defined in [RFC 2246] MUST NOT be
          used for confidentiality protection of passwords or data:
          
                  TLS_NULL_WITH_NULL_NULL
                  TLS_RSA_WITH_NULL_MD5
                  TLS_RSA_WITH_NULL_SHA
          
          The following ciphersuites defined in [RFC 2246] can be
          cracked easily (less than a week of CPU time on a standard CPU
          in 1997).  The client and server SHOULD carefully consider the
          
          
          
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          value of the password or data being protected before using
          these ciphersuites:
          
                  TLS_RSA_EXPORT_WITH_RC4_40_MD5
                  TLS_RSA_EXPORT_WITH_RC2_CBC_40_MD5
                  TLS_RSA_EXPORT_WITH_DES40_CBC_SHA
                  TLS_DH_DSS_EXPORT_WITH_DES40_CBC_SHA
                  TLS_DH_RSA_EXPORT_WITH_DES40_CBC_SHA
                  TLS_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA
                  TLS_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA
                  TLS_DH_anon_EXPORT_WITH_RC4_40_MD5
                  TLS_DH_anon_EXPORT_WITH_DES40_CBC_SHA
          
          The following ciphersuites are vulnerable to man-in-the-middle
          attacks, and SHOULD NOT be used to protect passwords or
          sensitive data, unless the network configuration is such that
          the danger of a man-in-the-middle attack is tolerable:
          
                  TLS_DH_anon_EXPORT_WITH_RC4_40_MD5
                  TLS_DH_anon_WITH_RC4_128_MD5
                  TLS_DH_anon_EXPORT_WITH_DES40_CBC_SHA
                  TLS_DH_anon_WITH_DES_CBC_SHA
                  TLS_DH_anon_WITH_3DES_EDE_CBC_SHA
          
          A client or server that supports TLS MUST support at least:
          
                  TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA
          2.4.3  User Groups
          
          User Group is used to represent a collection of CUs or other
          UGs that can be referenced in VCARS. A UG is represented in
          CAP as a UPN. The CUA cannot distinguish between a UPN that
          represents a CU or a UG.
          
          UGs are expanded as necessary by the CS. The CS MUST accept a
          CUA request for UG expansion, although the CS may be
          configured to restrict some responses. The CS MAY expand a UG
          (including nested UGs) to obtain a list of unique CUs.
          Duplicate UPNs are filtered during expansion. Incomplete
          expansion should be treated as a failure.
          
          Groups may be in a directory with its own ACL model and CAP
          should use the directory service to expand a UPN subject to
          the directory service access control model for the
          authenticated entity.
          
          The CS SHOULD not preserve UG expansions across operations. A
          UG may reference a static list of members, or it may represent
          a dynamic list. Each operation SHOULD generate its own
          
          
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          expansion in order to recognize changes to UG membership.
          However, during fan out to other CSs, the originating CS
          SHOULD expand all UGs so that the target CS receives only a
          list of unique CUs. This is to prevent confusion when two CSs
          do not share the same UG database or directory.
          
          CAP does not define commands or methods for managing UGs.
          
          Small UG:
            The Three Stooges. There is only and always three at any
            one time.
          
          Large UG:
            The MIT graduating class of 1999. This is a static list.
          
          Dynamic UG:
            The IETF membership which is a large and changing list of
            members.
          
          Nested UG:
            The National Football League, made up of the AFC and NFC,
            which are   made up of 3 divisions each...
          
          2.4.4  Access Rights - Summary
          
          Access rights are used to grant or deny access to a calendar
          for a CU. CAP defines a new component type called a Vcalendar
          Access Right (VCAR). Specifically, a VCAR grants, or denies,
          UPNs the right to read and write components, properties, and
          parameters on calendars within a CS.
          
          The VCAR model does not put any restriction on the sequence in
          which the object and access rights are created. That is, an
          event associated with a particular VCAR might be created
          before or after the actual VCAR is defined. In addition, the
          VCAR and VEVENT definition might be created in the same
          iCalendar object and passed together in a single command.
          
          All rights MUST be denied unless specifically granted;
          individual VCARs MUST be specifically granted to an
          authenticated CU.
          
          The access for a particular UPN is the union of all grants for
          that UPN minus the union of its denies.
          
          2.4.4.1   VCalendar Access Right (VCAR)
          
          
          
          
          
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          Access rights within CAP are specified with the "VCAR"
          calendar component, "RIGHTS" value type and the "GRANT",
          "DENY" and "CARID" component properties.
          
          Properties within an iCalendar object are unordered. This also
          is the case for the "GRANT", "DENY" and "CARID" properties.
          Likewise, there is no implied ordering required for components
          of a "RIGHTS" value type other than that specified by the
          ABNF. [EDITOR'S NOTE, this requires a lot of review. We think
          that this paragraph may be incorrect. ]
          
          For details on the VCAR syntax please see section <forward
          ref>
          
          2.4.4.2   Decreed VCARs
          
          A CS MAY choose to implement and allow persistent immutable
          VCARs, that are configured by the CS Administrator, which
          apply to all calendars on the server.
          
          When a user attempts to modify a decreed VCAR an error will be
          returned, indicating that the user has insufficient
          authorization to perform the operation.
          
          The CAP protocol does not define the semantics used to
          initially create a decreed VCAR. This administrative task is
          out side the scope of the CAP protocol.
          
          For example an implementation or a CS administrator may wish
          to define a VCAR that will always allow the calendar owners to
          have full access to their own calendars.  The GRANT property
          allows the OWNERs all (OBJECT=*) access to their own calendar
          objects.  The DENY property disallows anyone (UPN=*) from
          being able to delete or modify this VCAR.
          
             BEGIN:VCAR
             CARID:Users Default Access
             GRANT:UPN=OWNER;OBJECT=*;OBJECT=OBJECT=METHOD;VALUE=*
             DENY:UPN=*;OBJECT=VCAR;OBJECT=CARID;
              VALUE="Users Default Access"
              ;OBJECT=METHOD,VALUE=DELETE,MODIFY
             END:VCAR
          
          Decreed VCARs MUST be readable by the calendar owner in
          standard VCAR format.
          
          2.4.5  Inheritance
          
          
          
          
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          Calendars inherit VCARs from their parent calendar. Calendars
          whose parent is the Calendar Store inherit VCARs from the
          Calendar Store.
          
          VCARs specified in a calendar or a sub-calendar override all
          inherited VCARs.
          
          2.4.6  CAP Session Identity
          
          A CAP session has an associated set of authentication
          credentials, from which is derived a UPN. This UPN is the
          identity of the CAP session, and is used to determine access
          rights for the session.
          
          The CUA may change the identity of a CAP session by calling
          the "IDENTIFY" command. The Calendar Service only permits the
          operation if the session's authentication credentials are good
          for the requested identity. The method of checking this
          permission is implementation dependent, but may be thought of
          as a mapping from authentication credentials to UPNs. The
          "IDENTIFY" command allows a single set of authentication
          credentials to choose from multiple identities, and allows
          multiple sets of authentication credentials to assume the same
          identity.
          
          For anonymous access the identity of the session is "@", a UPN
          with a null username and null realm. A UPN with a null
          username, but non-null realm, such as "@foo.com" may be used
          to mean any identity from that realm, which is useful to grant
          access rights to all users in a given realm. A UPN with a non-
          null username and null realm, such as "bob@" could be a
          security risk and MUST NOT be used.
          
          Since the UPN includes realm information it may be used to
          govern calendar store access rights across realms. However,
          governing access rights across realms is only useful if login
          access is available. This could be done through a trusted
          server relationship or a temporary account.
          
          The "IDENTIFY" command provides for a weak group
          implementation. By allowing multiple sets of authentication
          credentials belonging to different users to identify as the
          same UPN, that UPN essentially identifies a group of people,
          and may be used for group calendar ownership, or the granting
          of access rights to a group.
          
          Examples:
          
          Small UG:
          
          
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                  The Three Stooges.  There will always be three, it
                  will not change.
          
          Large UG:
                  The MIT graduating class of 1999.  This is a static
                  list.
          
          Dynamic UG:
                  The IETF membership, which is a large and changing
                  list of members.
          
          Nested UG:
                  The National Football League, made up of the AFC and
                  NFC, which are made up of 3 divisions each.
          
          2.5 Roles
          
          CAP defines methods for managing [iCAL] objects on a Calendar
          Store and exchanging [iCAL] objects for the purposes of group
          calendaring and scheduling between "Calendar Users" (CUs) or
          "User Groups" (UGs). There are two distinct roles taken on by
          CUs in CAP. The CU who creates an initial event or to-do and
          invites other CUs or UGs as attendees takes on the role of
          "Organizer". The CUs or UGs asked to participate in the group
          event or to-do take on the role of "Attendee". Note that
          "role" is also a descriptive parameter to the "ATTENDEE"
          property. Its use is to convey descriptive context to an
          "Attendee" such as "chair", "REQ-PARTICIPANT" or "NON-
          PARTICIPANT" and has nothing to do with the scheduling
          workflow.
          
          2.6 Calendar Addresses
          
          Calendar addresses are URIs that are modeled after URLs [URL].
          CAP uses the following forms of URI.
          
                  [[<scheme>]://<csid>[:<port>]/]<relativeCALID>
          
          where:
          
                  <scheme> is "cap", the protocol described in this
                  memo.
          
                  <csid> is the Calendar Store ID. It is the network
                  address of the computer on which the CAP server is
                  running.
          
          
          
          
          
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                  <port> is optional. Its default value is 5229. The
                  port must be present in the URL if the CAP server
                  does not listen on this default port of 5229.
          
                  <relativeCALID> is an identifier that uniquely
                  identifies the calendar on a particular calendar
                  store. There is no implied structure in a Relative
                  CALID. It is an arbitrary string of printable 7 bit
                  ASCII characters. It may refer to the calendar of a
                  user or of a resource such as a conference room. It
                  MUST be unique within the calendar store. It is
                  recommended that the Relative CALID be globally
                  unique.
          
          If the <scheme> and <csid> are present the calendar address is
          said to be "qualified". Senders are required to supply the
          <relativeCALID> portion of the address. A qualified calendar
          address is required when the <csid> of the target calendar
          address differs from that of the CAP server receiving the
          command.
          
          Examples of CAP URIs:
          
                  cap://calendar.example.com/user1
                  ://calendar.example.com/user1
                  user1
                  cap://calendar.example.com/conferenceRoomA
                  cap://calendar.example.com/89798-098-zytytasd
          
          For a user currently authenticated to a CAP server on
          calendar.example.com, the first three addresses refer to the
          same calendar.
          
          
          2.7 Extensions to iCalendar
          
          In mapping the CAP command set, query feature, and access
          rights onto the iCalendar format, several extended iCalendar
          methods and components are defined by this memo.
          
               * The search function is specified with the new
                  iCalendar QUERY method. The QUERY method makes use of
                  a new component, called VQUERY, that contains the
                  search filter. The component consists of a set of new
                  properties: EXPAND, MAXRESULTS, MAXRESULTSSIZE, QUERY
                  and QUERYNAME, that define the search filter. Note
                  that QUERY simply is the filter that is used by the CS
                  to select the data used in METHOD:READ, METHOD:CREATE,
          
          
          
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                  METHOD:MODIFY, METHOD:DELETE, any other METHOD that is
                  defined to use a QUERY filter.
               * Access control is specified the the new iCalendar VCAR
                  component.
               * The iCalendar METHOD property format has been updated
                  with new values.
               * A new iCalendar component, VCOMMAND, has been added.
                  VCOMMANDs are needed to specify CAP commands.
               * TARGET is a new property within the VCOMMAND
                  component. It indicates  the calendars to which the
                  command applies
               * CMDID is a Command ID that is used in a VCOMMAND to
                  uniquely identify  a command. Responses to a VCOMMAND
                  will contain the same CMDID.
          
          2.8 Relationship of RFC 2446 (ITIP) to CAP
          
          [iTIP] describes scheduling methods which result in indirect
          manipulation of calendar components. CAP methods provide
          direct manipulation of calendar components. In the CAP
          calendar store model, scheduling messages are conceptually
          kept separate from other calendar components. This is modeled
          with the VSCHEDULE queue. Note that this is a conceptual
          model, the actual storage details are left to implementations.
          The model is shown pictorially as follows:
          
          
               +-----------------VCALENDAR-------------------+
               |                                             |
               |  +-----------+  +-------VSCHEDULE---------+ |
               |  | VEVENTs   |  | PUBLISH messages        | |
               |  | VTODOs    |  | REQUEST messages        | |
               |  | VJOURNALs |  | REPLY messages          | |
               |  |           |  | ADD messages            | |
               |  |           |  | CANCEL messages         | |
               |  |           |  | REFRESH messages        | |
               |  |           |  | COUNTER messages        | |
               |  |           |  | DECLINECOUNTER messages | |
               |  +-----------+  +-------------------------+ |
               +---------------------------------------------+
          
          
          The METHOD is saved along with components. Scheduled
          components become booked components when the METHOD changes
          from an ITIP method to the CAP storage method CREATE.  For
          example, a component whose METHOD is "REQUEST" is scheduled.
          The component becomes booked when the METHOD is changed to
          "CREATED".
          
          
          
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          Several scheduled entries can be in the CS for the same UID.
          They are consolidated when booked. Or they are removed from
          the CS.
          
          For example, if you were on vacation, you could have a REQUEST
          to attend a meeting and several updates to that meeting. Your
          CUA would have to READ them out of the CS using CAP, process
          them, determine what the final state of the object from a
          possible combination of user input and programmed logic. Then
          the CUA would instruct the CS to CREATE a new booked entry or
          MODIFY an existing entry. Followed by a DELETE of all of these
          now old scheduling requests in the CS. See [iTIP] for details
          on resolving multiple [iTIP] scheduling entries.
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
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          3  State Diagram
          
          This section describes the states of the transport connection
          between a CUA and a CS. The state diagram is shown below.
          State names are shown with first letter capitalized. Commands
          used to switch between states are shown next to an arrow
          connecting the states. The commands are listed in all capital
          letters. A condition that causes a state to change is shown in
          lower case letters.
          
          
           STARTTLS /
           CAPABILITY
          +-------+
          |       |                       +---------------+
          |   +-----------+ AUTHENTICATE  |               |
          +-->| Connected |-------------->| Authenticated |
              +-----------+               |               |
                |                         +---------------+
                |                                |
                |                                |     +-----+
                |                                V     |     |STARTTLS /
                |                         +---------------+  |IDENTIFY
                |                         |               |<-+
                |                         |   Identified  |<-----+
                |                +--------|               |      |
                |                |        +---------------+      |
                |                |                |       command|
                V                |DISCONNECT      |     completes|
              +--------------+   |                |              |
              | Disconnected |<--+                |              |
              +--------------+                    |SENDDATA      | ABORT
                     A                            |              |
                     |                            V              |
                     |    DISCONNECT      +---------------+      |
                     +--------------------|    Receive    |------+
                                          |               |<--+
                                          +---------------+   |
                                                         |    |
                                                         +----+
                                                        CONTINUE
          
          The connection begins the Connected state when a CUA connects
          to a CAP server. The capabilities of the CS are reported in
          the response from the CS. From this state, the CUA can issue
          the DISCONNECT command to terminate the connection, the
          CAPABILITY, STARTTLS, or AUTHENTICATE commands. One use of the
          CAPABILITY command at this stage is to determine the supported
          
          
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          authentication mechanisms supported by the server. Once the
          STARTTLS command has been successfully executed from either
          the Connected or Authenticated state, it must not be executed
          again.
          
          If an AUTHENTICATE command is successful, the connection
          enters the Authenticated state and then immediately goes to
          the IDENTIFIED state. While in the Identified state, allow
          CALIDEXPAND and UPNEXPAND commands. From here the CUA can
          issue the CAPABILITY command. The capabilities the server
          offers in the Authenticated state may be different than those
          in the Connected state to allow for the users realm to be used
          to grant or deny features. The CUA can also use the IDENTIFY
          command to change the identity of the user subject to access
          control. The connection remains in the Authenticated state
          after the CAPABILITY command completes. The CUA can issue the
          DISCONNECT command to terminate the connection. The SENDDATA
          command can be used to send a request to read, write, modify,
          or delete data on the server.
          
          After the SENDDATA command has been issued the connection
          enters the Receive state while the CUA awaits and reads a
          server reply. Normally, the server handles the command, sends
          a reply which is read by the CUA and the connection returns to
          the Authenticated state. The CUA may have issued the SENDATA
          command with a maximum latency time. This informs the server
          that the CUA expects a response within the maximum latency
          time, even if the command was not completed. When the server
          is unable to complete the command in the maximum latency time,
          it issues an appropriate reply code and waits for the CUA to
          tell it how to proceed. If the CUA issues a CONTINUE command
          the server continues processing the command and the connection
          remains in the Receive state. If the CUA issues the ABORT
          command the server need not process the command any further
          and the connection returns to the Authenticated state. The
          DISCONNECT command can also be issued from the Receive state.
          
          4  Protocol Framework
          
          4.1 CAP Application Layer
          
          The CAP application layer is used for the manipulation of the
          calendar store. Commands and responses are transmitted between
          the CUA and CS inside "VCALENDAR" component wrappers. Commands
          are specified as the value of a "METHOD" property, and
          responses are specified as the value of a "REQUEST-STATUS"
          property.
          
          
          
          
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          4.2 CAP Transfer Protocol
          
          The CAP transfer protocol defines the format of data
          transmitted between a CUA and the CS.
          
          CAP transfer protocol commands are transmitted using the
          underlying transport. The transport used is a TCP/IP socket
          connection between the CUA and the CS. The default port that
          the CS listens for connections on is port 5229.
          
          Messages sent between the CUA and CS are formatted as a
          command followed by any associated data:
          
          <command> [<command data>]
          
          
          Response Format
          
          Server responses consist of a response code and any
          parameters:
          
          <transfer-level response-code> [response-args] [; debug-text ]
          <CRLF>.<CRLF>
          [<application-data>]
          <CRLF>.<CRLF>
          
          The response-args are defined in Section 8. The debug-text is
          human-readable information for protocol debugging and is
          optional and is only used to aid developers writing CSs and
          CUAs.  The debug-text MUST not be depended on by CUAs in
          normal interactions with a CS.
          
          The optional application-data begins on the next line.
          
          The response is terminated with the second <CRLF> "." <CRLF>
          sequence. Any <CRLF> "." sequences which appear in the
          transmitted data must be quoted by placing an additional "."
          between the <CRLF> and the ".". For example, the following
          sequences of characters in the application data:
          
          .
          ..2
          ...3
          
          are quoted as follows:
          
          ..
          ...2
          ....3
          
          
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          4.3 Pipelining of Commands
          
          If the CS returns a PIPELINE number greater then one (1) as a
          result of a CAPABILITY command the CUA can send up to PIPELINE
          VCOMMANDS without waiting for the CS to reply.
          
          
          4.4 Auto-logout Timer
          
          If a server has an inactivity auto-logout timer, that timer
          MUST be of at least 15 minutes duration if there is no value
          of AUTOLOGOUTTIME returned in the CS CAPABILITY reply. The
          receipt of ANY command from the client during that interval
          MAY reset the auto-logout timer, subject to CS administrators
          policy. A CUA may be discouraged from attempts to do useless
          things only to keep the connection alive.
          
          A CS MAY have different AUTOLOGOUTTIME values depending on the
          UPN or the realm of the UPN.
          
          When a timeout occurs, the server drops the connection to the
          CUA.
          
          4.5 Bounded Latency
          
          CAP is designed so that the CUA can either obtain an immediate
          response from a request or discover within a specified amount
          of time that the request could not be completed in the
          requested amount of time. When the CUA initiates a command
          that the server cannot complete within the specified latency
          time, the server returns an appropriate response code. The CUA
          then issues either a CONTINUE or ABORT command.  The ABORT
          command immediately terminates the command in progress
          identified by CMDID and the connection returns to the
          Authenticated state.  The CONTINUE command instructs the
          server to continue processing the command identified by the
          CMDID.
          
          4.6 Data Elements
          
          The data elements for CAP are [MIME] encapsulated iCalendar
          objects.
          
          5  Formal Command Syntax
          5.1 Searching and Filtering
          
          
          
          
          
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          This section describes CAPs selecting and filtering entities
          within a calendar store. It is based on the Standard Query
          Language (SQL) defined in [SQL].
          
          5.1.1  Grammar For Search Mechanism
          
          
             search     = "BEGIN:VQUERY" CRLF
                          [expand] [maxresults] [maxsize] querycomp
                          "END:VQUERY" CRLF
          
             expand     = "EXPAND" ":" ( "TRUE" / "FALSE")
                        # the default is EXPAND:FALSE
          
             comp-name  = "VEVENT" / "VTODO" / "VJOURNAL"
                        / "VTIMEZONE" / "VALARM" / "VFREEBUSY"
                        / "VCAR" / iana-name / x-name
          
             maxresults = integer
          
             maxsize    = integer
          
             querycomp  = ( query ) / ( queryname query ) / queryname
          
             queryname  = "QUERYNAME:" text
          
             query      = "QUERY:" ( query-min / query-92 )
             #
             # NOTE: query-min MUST be implemented in CSs.
             #
             #   query-92 is ONLY used if CAPABILITY returns SQL-92
             #   as the QUERYLEVEL value or if QUERYLEVEL is not
             #    specified.
             #
          
             query-min      = capselect-min capfrom-min capwhere-min
          
             capselect-min  = "SELECT" capmin-cols "FROM" capmin-comps
                              "WHERE" capmin-cmp
          
             capmin-col     = # Any property name found in any of the
                              components.
          
             capmin-cols    = ( capmin-col / capmin-col ","
                              capmin-cols )
          
             capmin-comps   = ( comp-name / comp-name ","
                              compmin-comps )
          
          
          
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             capmin-cmp     = ( colname cmpmin-oper colvalue
                            / colname cmpmin-oper colvalue
                              capmin-logical capmin-cmp )
          
             colname        = ( # Any valid component property name.
                            / "*" )
          
             cmpmin-oper    = ( " = "  / " != " / " < " / " > " / " <= "
                            / " >= " )
          
             capmin-logical = ( " AND " / " OR " )
          
             query-92       = capselect-92 capfrom-92 capwhere-92
                              caporderby-92
          
             capselect-92   = # Any valid [SQL] string that goes into
                              a SELECT clause.
          
             capfrom-92     = # Like capmin-comps except embedded spaces
                              # are allowed between commas - per [SQL].
          
             capwhere-92    = # Any valid [SQL] string that goes into a
                              # WHERE clause.
          
             caporderby-92  = # Any valid [SQL] string that goes into a
                              # ORDERBY clause.
          
          
          5.1.2  SQL-MIN notes
          
          (1) No inlined spaces are allowed if not in the grammar above.
          
          (2) Note that cmpmin-oper and capmin-logical elements are
              surrounded by exactly one space.
          
              Use 'VEVENT,VTODO', not 'VEVENT, VTODO'
              Use 'DTSTART <= 20000605T131313Z', not
                  'DTSTART<=  20000605T131313Z'.
              Use ' AND ' and ' OR ', not 'AND' and not 'OR'.
          
          (3) There is no ORDERBY.  Sorting will take place in the order
              the columns are supplied in the command.
          
          (4) The CS MUST sort at least the first column.The CS MAY sort
              additional columns.
          
          (5) If EXPAND=FALSE and if colname is "*" sorting will be by
              the DTSTART  value ascending.
          
          
          
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              If EXPAND=TRUE and if colname is "*" sorting will be by
              the RECURRENCE-ID value ascending.
          
              If colname is "*" and capmin-coms is VALARM only then
              sorting will be by TRIGGER time in GMT ascending.
          
          (6) SQL-MIN MUST be implemented.
          
          5.1.3  SQL-92 notes
          
          (1) Although this memo specifies that any [SQL] query can be
          used, some of the [SQL] grammar is optional and therefore is
          considered optional in CSs advertising an SQL-92
          implementation with CAPABILITY.
          
          (2) A CS implementation MAY implement SQL-92. If a CS does not
          implement SQL-92 then it MUST advertise SQL-MIN in the
          capability reply.
          
          5.1.4  Example, Query by UID
          
          This example would select the entire contents of uid123 and
          not expand any multiple instances of the component.  If the
          CUA does not know if 'uid123' was a VEVENT, VTODO, VJOURNAL,
          or other component, then all components that the CUA supports
          MUST be supplied on the QUERY property. This example assumes
          the CUA only supports VTODO and VEVENT.
          
          If the results were empty it could also mean that 'uid123' was
          a property in a component other than a VTODO or VEVENT.
          
            BEGIN:VQUERY
            QUERY:SELECT * FROM VEVENT,VTODO WHERE UID = 'uid123'
            END:VQUERY
          
          This example would select the entire contents of uid123 and
          would expand any instances of the component after applying any
          recurrence rules. This query could select multiple instances
          of components each with the same UID.  Each instance would
          have a unique RECURRENCE-ID of the expanded component.
          
            BEGIN:VQUERY
            EXPAND:TRUE
            QUERY:SELECT * FROM VEVENT,VTODO WHERE UID = 'uid123'
            END:VQUERY
          
          5.1.5  Query by Date-Time range
          
          
          
          
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          This query selects the entire contents of every booked VEVENT
          that has an instance less than or equal to July 31st, 2000
          23:59:59 Z and greater than or equal to July 1st, 2000
          00:00:00 Z
          
            BEGIN:VQUERY
            EXPAND:TRUE
            QUERY:SELECT * FROM VEVENT
              WHERE RECURRENCE-ID >= '20000801T000000Z'
              AND RECURRENCE-ID <= '20000831T235959Z'
              AND METHOD = 'CREATE'
            END:VQUERY
          
          5.1.6  Query for all Non-Booked Entries
          This example selects the entire contents of all scheduling
          (non-booked) VEVENTS in the CS. The default for EXPAND is
          FALSE, so the recurrence rules will not be expanded.
          
            BEGIN:VQUERY
            QUERY:SELECT * FROM VEVENT,VTODO WHERE METHOD != 'CREATE'
            END:VQUERY
          
          The following example fetches the UIDs of all non-booked
          VEVENTs and VTODOs.
          
            BEGIN:VQUERY
            QUERY:SELECT UID FROM VEVENT,VTODO WHERE METHOD != 'CREATE'
            END:VQUERY
          
          
          5.1.7  Query with Subset of Properties by Date/Time
          
          This MUST implement is similar to the one above, except only
          the named properties will be selected and all booked and non-
          booked components will be selected that have a DTSTART from
          Feb 1st to Feb 10th.
          
            BEGIN:VQUERY
            QUERY:SELECT UID,DTSTART,DESCRIPTION,SUMMARY FROM VEVENT
              WHERE DTSTART >= '20000201T000000Z'
              AND DTSTART <= '20000210T235959Z'
            END:VQUERY
          
          
          5.1.8  Components With Alarms In A Range
          This example fetches all components with an alarm that
          triggers within the specified time range. In this case only
          the UID, SUMMARY, and DESCRIPTION will be selected for all
          booked VEVENTS that have an alarm between the two date-times.
          
          
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            BEGIN:VQUERY
            EXPAND:TRUE
            QUERY:SELECT UID,SUMMARY,DESCRIPTION FROM VEVENT
              WHERE VALARM.TRIGGER >= '20000101T030405Z'
              AND VALARM.TRIGGER <= '20001231T235959Z'
              AND METHOD = 'CREATE'
            END:VQUERY
          
          6  Access Rights
          
          Access rights within CAP are specified with the "VCAR"
          calendar component, "RIGHTS" value type and the "GRANT",
          "DENY" and "CARID" component properties.
          
          Individual calendar access rights MUST be specifically granted
          to an authenticated calendar user (i.e., UPN); all rights are
          denied unless specifically granted.
          
          Properties within a VCAR must be evaluated in the order
          provided.
          
          
          6.1 VCAR Inheritance
          
          Calendar access rights specified in a calendar store are
          inherited as default calendar access rights for any calendar
          in the parent calendar store. Likewise, any calendar access
          rights specified in a root calendar are inherited as default
          calendar access rights for any sub- calendar to the root
          calendar. By implication, calendar access rights specified in
          a sub-calendar are inherited as default calendar access rights
          for any calendars that are hierarchically below the sub-
          calendar.
          
          Calendar access rights specified in a calendar override any
          default calendar access rights. Calendar access rights
          specified within a sub-calendar override any default calendar
          access rights.
          
          
          6.2 Access Control and NOCONFLICT
          
          The TRANSP property can take on values (TRANSPARENT-
          NOCONFLICT, OPAQUE-NOCONFLICT) that prohibit other events from
          overlapping it. This setting overrides access While access
          control may allow a UPN to store an event on a particular
          calendar. , the CONFLICTS Calendar or component setting may
          prevent it, returning an error code "6.3"
          
          
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          7  Commands and Responses
          
          CAP commands and responses are described in this section.
          
          Command arguments, identified by "Arguments:" in the command
          descriptions below, are described by function, not by syntax.
          The precise syntax of command arguments is described in the
          Formal Syntax section.
          
          Some commands cause specific server data to be returned; these
          are identified by "Data:" in the command descriptions below.
          See the response descriptions in the Responses section for
          information on these responses, and the Formal Syntax section
          for the precise syntax of these responses.
          
          The "Result:" in the command description refers to the
          possible status responses to a command, and any special
          interpretation of these status responses.
          
          Commands have the general form:
          
                  <command> [arguments...]
          
          where <command> is a command listed in the table above. A
          command MAY have arguments. Arguments are defined in the
          detailed command definitions below.
          
          Responses to commands have the following general form:
          
                  responseCode [sep transportDescr sep
                  [applicationDescr]]
                  CRLF "." CRLF
          
          In the examples below, lines preceded with "S:" refer to the
          sender and lines preceded with "R:" refer to the receiver.
          Lines in which the first non-whitespace character is a "#" are
          editorial comments and are not part of the protocol.
          
          
          7.1 Transfer Protocol Commands
          
          
          7.1.1  Initial Connection
          
          Arguments:  none
          
          Data:       none
          
          
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          Result:     2.0  - success.
                      8.1  - server too busy
          
          Upon session startup, the server sends a response of 2.0 to
          indicate that it is ready to receive commands. A response of
          8.1 indicates that the server is too busy to accept the
          connection. In addition, the general capabilities of the CS
          are reported in the response from the CS. These capabilities
          may be different than those reported in the authenticated
          state.
          
          
          7.1.2  ABORT Command
          
          Arguments:  [CMDID]
          
          Data:       none
          
          Result:     2.0 - success
                      2.2 - no command is in progress
          
          The ABORT command is issued by the CUA to stop a command.  A
          common usage could be to ABORT a command whose latency time
          has been exceeded. When the latency time is specified on the
          SENDATA command, the CS must issue a reply to the CUA within
          the specified time. It may be a reply code indicating that the
          CS has not yet processed the request. The CUA must then tell
          the server whether to continue or abort.
          
          The CUA can issue the ABORT command at any time after the
          SENDATA command has been completed but before receiving a
          reply.
          
          If CMDID is supplied then the command identified by CMDID is
          aborted.
          
          If CMDID is not supplied then the fist command that is still
          pending is aborted.
          
          
          7.1.3  AUTHENTICATE Command
          
          Arguments:  <SASL mechanism name> [<initial data>]
          
          Data:       continuation data may be requested
          
          Result:
            2.0 - Authenticate completed, now in authenticated
          
          
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                  state.
           6.0 -  Failed authentication.
           6.1 -  Authorization identity refused.
           6.2 -  Sender aborted authentication, authentication
                exchange cancelled.
           6.3 -  Unsupported Authentication Mechanism.
           6.4 -  Temporary failure (back end authentication
                  server down).
           6.5 -  Authentication exchange cancelled.
           6.6 -  Authentication mechanism too weak.
           6.7 -  Encryption required.
           6.8 -  Pass phrase expired.  The pass phrase was
                  correct but expired. The user will have to
                  contact a pass phrase change server prior to
                  authenticating.
           6.9 -  The user is valid but the server does not
                  have an entry in the authentication database
                  for the requested mechanism (e.g., DIGEST-
                  MD5). If the user successfully authenticates
                  using a plain text password, then the back
                  end back end entry will be updated.  Note
                  that if the client chooses to fall back to
                  plain text password authentication it should
                  enable an encryption layer or get user-con-
                  firmation that a one-time transition is ac-
                  ceptable.
           6.10 -  User account disabled. The user will have to
                   contact the system administrator to  get  the
                   account re-enabled.
            9.1 -  Unexpected command.
          
          
          The capabilities of the CS in the authenticated state are
          reported in the response from the CS. These may be different
          than the capabilities in the Connected, but unauthenticated
          state.
          
          The AUTHENTICATE command is used by the CUA to identify the
          user to the CS. CAP supports a number of authentication
          methods, the SASL specification for authentication is the
          preferred method.
          
          If STARTTLS is negotiated prior to the AUTHENTICATE command,
          the client MUST discard all information about the CS
          capabilities fetched prior to the TLS negotiation.  In
          particular, the value of supported SASL Mechanisms MAY be
          different after TLS has been negotiated.
          
          
          
          
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          If a SASL security layer is negotiated, the client MUST
          discard all information about the CS capabilities fetched
          prior to SASL.  In particular, if the client is configured to
          support multiple SASL mechanisms, it SHOULD fetch supported
          SASL Mechanisms both before and after the SASL security layer
          is negotiated and verify that the value has not changed after
          the SASL security layer was negotiated.  This detects active
          attacks which remove supported SASL mechanisms from the
          supported SASL Mechanisms list.
          
          <initial data> is an optional parameter which can be used for
          mechanisms which require an initial response from the CUA.
          
          The AUTHENTICATE command is followed by an authentication
          protocol exchange, in the form of a series of CS challenges
          and CUA responses, per the relevant RFC that describes the
          specific SASL mechanism being used.
          
          Cancelling the authentication process during its negotiation
          is implementation specific and not within scope of the CAP
          specification.
          
          If a security layer was negotiated it comes into effect for
          the CS starting with the first octet transmitted after the
          CRLF which follows the 2.0 reply code, and for the CUA
          starting with the first octet after the CRLF of its last
          response in the authentication exchange. Encrypted data is
          transmitted as described in SASL.
          
          The service name specified by this protocol's profile of SASL
          is "cap". [EDITORS NOTE: this must be registered with IANA,
          has anyone done this yet?]
          
          The result of the AUTHENTICATE command includes data
          indicating the identity which has been assigned to the
          session, derived from the supplied authentication credentials,
          and/or authorization identifier.  A CAP session does not have
          an identity until the CUA has issued the "AUTHENTICATE"
          command.
          
          The CUA may not issue the "AUTHENTICATE" command multiple
          times, even if the first attempt was aborted. If a CUA
          attempts to do this the CS must terminate the session.
          
          Here is an example of a successful authentication:
          
          
             C: AUTHENTICATE KERBEROS_V4
             S: AmFYig==
          
          
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             C: BAcAQU5EUkVXLkNNVS5FRFUAOCAsho84kLN3/IJmrMG+25a4DT
             S: or//EoAADZI=
             C: DiAF5A4gA+oOIALuBkAAmw==
             S: 2.0
             S: .
             S: Content-Type:text/calendar; method=REQUEST;
             S:  charset=US-ASCII
             S: Content-Transfer-Encoding: 7bit
             S:
             S: BEGIN:VCAP
             S: PRODID:-//ACME/CAPserver//EN
             S: VERSION:2.1
             S: IDENTITY=bill@example.com
             S: CAPVERSION=1.0
             S: ITIPVERSION=1.0
             S: AUTH=KERBEROS_V4
             S: AUTH=DIGEST_MD5
             S: CAR=CAR-FULL-1
             S: MINDATE=19700101T000000Z
             S: MAXDATE=20370201T000000Z
             S: END:VCAP
             S: .
          
          This example shows a failed authentication:
          
             C: AUTHENTICATE KERBEROS_V4
          
             S: AmFYig==
             C: BAcAQU5EUkVXLkNNVS5FRFUAOCAsho84kLN3/IJmrMG+25a4DT
             S: .
             S: 6.0
             S: .
             S: .
          
          
          7.1.3.1   AUTHENTICATE ANONYMOUS
          
          RFC-2245 defines the Anonymous SASL mechanism. This RFC states
          that "the mechanism consists of a single message from the
          client to the server. The client sends optional trace
          information in the form of a human readable string. The trace
          information should take one of three forms: an Internet email
          address, an opaque string which does not contain the '@'
          character and can be interpreted by the system administrator
          of the client's domain, or nothing. For privacy reasons, an
          Internet email address should only be used with permission
          from the user."
          
          
          
          
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          RFC-2245 goes on to state, "A client which uses the user's
          correct email address as trace information without explicit
          permission may violate that user's privacy." Information about
          who accesses an anonymous CS on a sensitive subject (e.g., AA
          meeting times and locations) has strong privacy needs.
          "Clients should not send the email address without explicit
          permission of the user and should offer the option of
          supplying no trace token -- thus only exposing the source IP
          address and time."
          
          Example of CUA using the Capability command followed by an
          anonymous authentication:
          
             C: CAPABILITY
             S: 2.0
             S:CAPVERSION=1.0
             S:AUTH=KERBEROS_V4
             S:AUTH=DIGEST_MD5
             S:AUTH=ANONYMOUS
             S:.
             C:AUTHENTICATE ANONYMOUS
             S:+
             C:c21yaGM=
             S:2.0
          
          Subsequent to the initial Anonymous Authentication with a CS,
          a CUA will have to provide a UPN for some CAP operations. For
          anonymous access the UPN that MUST be used by the CUA is "@",
          a UPN with a null username and null realm. The user's normal
          UPN MUST not be used for the subsequent CAP operations.
          
          Note that the CS implementation may have internal audit logs
          that use the user's asserted UPN as trace information.
          However, this UPN will not appear on the wire after the
          initial SASL anonymous authentication.
          
          Use of the "@" UPN and wild-carding of UPNs within VCARs are
          covered in
          
          Section <forward ref>.
          
          
          7.1.4  CALIDEXPAND Command
          
          Arguments:  CalID
          
          Data:       no specific data for this command
          
          Result:     2.0 Successful, and requested data follows
          
          
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               2.1 Permission Denied
               2.2 Requested CSID not found
               2.3 Result exceeds MAXEXPANDLIST
               2.4 Misc. EXPAND error
          
          Return the members of the argument CalID.  Successful result
          yields one or more Calendars and/or Resource Calendars.  More
          than one C or RC returned implies that the CalID was a CC.
          
          Example:
          
          Example #1: Request lookup of CSID which is a Calendar
          Collection
          
             C: CALIDEXPAND cap://cal.example.com/calid14
             S: 2.0 cap://cal.example.com/calid14
             S: cap://cal.example.com/calid2
             S: cap://cal.example.com/calid5
             S: cap://cal.example.com/calid66
             S: .
          
          Example #2: Request lookup a CSID which is a Resource Calendar
          
             C: CALIDEXPAND cap://cal.example.com/conf5
             S: 2.0 cap://cal.example.com/conf5
             S: cap://cal.example.com/conf5
             S: .
          
          Example #3: Request CSID which exceeds MAXCALIDEXPANDLIST
          
             C: CALIDEXPAND cap://cal.example.com/calid76
             S: 2.0 cap://cal.example.com/calid76
             S: cap://cal.example.com/calid3
             S: cap://cal.example.com/calid12
             S: cap://cal.example.com/calid21
             S: cap://cal.example.com/calid33
             S: 2.3 Expansion resulted in too much data
             S: .
          
          Example #4: CS loses contact with directory server during
          CALIDEXPAND
          
             C: CALIDEXPAND cap://cal.example.com/calid76
             S: 2.0 cap://cal.example.com/calid76
             S: cap://cal.example.com/calid3
             S: cap://cal.example.com/calid5
             S: 2.4 Lost contact with directory server
             S: .
          
          
          
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          7.1.5  CAPABILITY Command
          
          Arguments:  none
          
          Data:       none
          
          Result:     capabilities as described below
          
          The CAPABILITY command returns information about the CAP
          server given the current state of the connection with the
          client. The values returned may differ depending on whether
          the connection is in the Connected or the Authenticated state.
          The return values may also be different for a secure versus a
          non-secure connection.
          
          Client implementations SHOULD NOT require any capability name
          beyond those defined in this specification, and MAY ignore any
          non-standard, experimental capability names. Non-standard
          experimental capability names MUST be prefixed with the text
          "X-". The prefix SHOULD also include a short character vendor
          identifier For example, "X-FOO-BARCAPABILITY", for the non-
          standard "BARCAPABILITY" capability of the implementor "FOO".
          This command may return different results in the Connected
          state versus the Authenticated state. It may also return
          different results depending on the UPN.
          
          
          Capability   Occurs     Description
          -------------------------------------------------------
          AUTH         1+         The authentication mechanisms
                                  supported. Implementations MUST
                                  implement at least
          
          CAPVERSION   1          Revision of CAP, MUST include at
                                  least "1.0". Comma separated
                                  values.
          
          ITIPVERSION  0 or 1     Revision of ITIP, MAY be present.
                                  If present, it MUST include at
                                  least "1.0"
          CAR          0 or 1     Indicates level of CAR support.
                                  CAR-MIN or CAR-FULL-1. If not
                                  specified the default is
                                  CAR-FULL-1.  Implementations
                                  MUST implement CAR-MIN.
                                  Implementations MAY implement
                                  CAR-FULL-1.
          
          
          
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          QUERYLEVEL   0 or 1     Indicates level of SQL support.
                                  SQL-MIN or SQL-92. If not
                                  specified the default is SQL-92.
                                  Implementations MUST implement
                                  SQL-MIN.  Implementations MAY
                                  implement SQL-92.
          
          MAXICALOBJECTSIZE
                       0 or 1     An integer value that specifies
                                  The largest ICAL object the server
                                  will accept in bytes. Objects
                                  larger than this will be rejected.
                                  A value of zero (0) indicates
                                  unlimited. The default is zero (0)
                                  if not specified.
          
          MAXDATE      0 or 1     The datetime value in GMT beyond
                                  which the server cannot accept. If
                                  not specified the default is
                                  99991231T235959Z.
          
          MAXCALIDEXPANDLIST
                       0 or 1     An integer value that specifies
                                  the maximum number of CalIDs that
                                  can be returned by the CALIDEXPAND
                                  Command. A value of zero (0)
                                  indicates unlimited which is the
                                  default if not specified.
          
          MAXUPNEXPANDLIST
                       0 or 1     An integer value that specifies
                                  the maximum number of UPNs that
                                  can be returned by the UPNEXPAND
                                  Command. A value of zero (0)
                                  indicates unlimited which is the
                                  default if not specified.
          
          MINDATE      0 or 1     The datetime value prior to which
                                  the server cannot accept. If not
                                  specified the default is
                                  00000101T000000Z.
          
          PIPELINE     0 or 1     An integer value that specifies
                                  the maximum number of commands a
                                  CUA may send without the CUA
                                  waiting for a reply from the CS.
                                  If not specified, the default
                                  value is one (1). A value of zero
                                  (0)indicates unlimited.
          
          
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          AUTOLOGOUTTIME
                       0 or 1     An integer value that specifies
                                  the default idle time in seconds
                                  the CS will wait before
                                  disconnecting an idle CUA.If the
                                  CS is busy the CS may adjust down
                                  the auto-logout timer.  If not
                                  specified, the value is 15 minutes
                                  (900 seconds). A value of zero (0)
                                  indicates unlimited connect time
                                  is allowed.
          
          
            Example:
          
          
            C: CAPABILTIY
            S: 2.0
            S: .
            S: CAPVERSION=1.0
            S: ITIPVERSION=1.0
            S: AUTH=KERBEROS_V4
            S: AUTH=DIGEST_MD5
            S: .
          
          
          7.1.6  CONTINUE Command
          
          Arguments: latency time in seconds (optional)
          
          Data:    none
          
          Result:   results from the command in progress
                    2.0.2 - reply pending.
          
          The CONTINUE command is issued by the client in response to a
          SENDATA timeout. When a timeout value is specified on the
          SENDDATA command, the server must issue a reply to the client
          within the specified time. If the latency time has elapsed
          prior to the server completing the command it returns a
          timeout response code. If the client wants the server to
          continue processing the command it responds with the CONTINUE
          command.
          
          If latencyTime is present, it must be a positive integer that
          specifies the maximum number of seconds the client will wait
          for the next response. If it is omitted, the receiver waits an
          indefinite period of time for the response.
          
          
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          In this example, the client requests a response from the
          server every 10 seconds.
          
            C: SENDDATA:10
            C: Content-Type:text/calendar; method=READ; component=VEVENT
            C:
            C: BEGIN:VCAP
            # etc
            C: END:VCAP
            C: .
            # after 10 seconds...
            S: .
            S: 2.0.2
            S: .
            S: .
            C: CONTINUE:10
            S: 2.0
            S: .
            S: Content-type:text/calendar;
            S:   Method=RESPONSE;Component=VDATA;
            S: Optinfo=VERSION:2.1
            S:
            S: BEGIN:VCAP
          
            S: VERSION:2.1
            S: CALID:cap://cal.example.com/relcal2
            # etc.
            S: END:VCAP
            S: .
          
          
          7.1.7  DISCONNECT Command
          
          Arguments: none
          
          Data:
          
          Result:   2.0
          
          The DISCONNECT command is used by a client to terminate a
          connection. It always succeeds.
          
          The CUA MUST wait for the CS 2.0 reply to ensure that TCP/IP
          (which knows nothing about CAP) can be sure the connection
          should go away. This avoids the CS connection being stuck in
          TCP-WAIT state.
          
          Example:
          
          
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            C: DISCONNECT
            # [ed. Note: should the client now wait for a response from
          the
            server
            #  before disconnecting? ]
            S: 2.0
            S: .
            S: .
            S: <drops connection>
            C: <drops connection>
          
          
          7.1.8. IDENTIFY Command
          
          Arguments: Identity to assume
          
          Data:      None
          
          Result:    2.0
                      .4 Identity not permitted
          
          The "IDENTIFY" command allows the CUA to select a new identity
          to be used for calendar access. This command may only be
          called in the Identified State.
          
          The CS determines through an internal mechanism if the
          credentials supplied at authentication permit the assumption
          of the selected the identity. If they do the session assumes
          the new identity, otherwise a security error is returned.
          
          
          7.1.8  SENDDATA Command
          
          Arguments: [latencyTime]
          
          Data:      a [MIME] encapsulated iCalendar object
          
          Result:    2.0.1 - Server will now accept input until
                             <CRLF>.<CRLF> is encountered.
          
          The SENDDATA command is used to send calendar requests and
          commands to the server. After a response code of 2.0.1 is
          issued the CUA sends a [MIME] encapsulated iCalendar object to
          the server. The end of this [MIME] data is signaled by the
          special sequence <CRLF>.<CRLF> .
          
          
          7.1.10. STARTTLS Command
          
          
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          Arguments: None
          
          Data:      None
          
          Result:    2.0
                     5  TLS not supported
          
          The "STARTTLS" command is issued by the CUA to indicate to the
          CS that it wishes to negotiate transport level security using
          [TLS]. If the CS does not support TLS it returns status code
          6.5. If the CS supports TLS it issues an initial response of
          2.0.12 indicating that the CUA should proceed with TLS
          negotiation. Once the TLS negotiation is complete the server
          returns the response code 2.0.
          
          After issuing the "STARTTLS" command the CUA issues the
          "AUTHENTICATE" command. The SASL external mechanism may be
          used if the CUA wishes to use the authentication id which was
          used in the TLS negotiation.
          
          The CUA MUST NOT issue a "STARTTLS" if it has already issued
          an "AUTHENTICATE" or "STARTTLS" command in this session. If a
          CUA does this the CS must terminate the session.
          
          The following examples illustrate the use of the "STARTTLS"
          command:
          
          Unsupported TLS:
          
            C: STARTTLS
            S: 6.5
          
          Supported TLS:
          
            C: STARTTLS
            S: 2.0.12
             <tls negotiation>
            S: 2.0
          
            S: .
            S: .
          
          
          7.1.8.1   UPNEXPAND Method
          
          Arguments: UPN
          
          Data:      no specific data for this command
          
          
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          Result:    2.0 - success
                     2.1 Permission Denied
                     2.2 Requested UPN not found
                     2.3 Result exceeds MAXUPNEXPANDLIST
                     2.4 Misc. UPNEXPAND error
          
          Return the members of the argument UPN. Successful result
          yields one or more CalIDs. More than one CalID returned
          implies that the UPN was a UG.
          
          Example #1: Request lookup of a UPN which is a CU
          
            C: UPNEXPAND upn@example.com
            S: 2.0 upn@example.com
            S: cap://cal.example.com/calid3
            S: .
          
          Example #2: Request lookup of UPN which is a UG
          
            C: UPNEXPAND group@example.com
            S: 2.0 group@example.com
            S: cap://cal.example.com/calid3
            S: cap://cal.example.com/calid6
            S: cap://cal.example.com/calid1342
            S: .
          
          Example #3: Request lookup exceeds MAXUPNEXPANDLIST
          
            C: UPNEXPAND group@example.com
            S: 2.0 group@example.com
            S: cap://cal.example.com/calid3
            S: cap://cal.example.com/calid12
            S: cap://cal.example.com/calid21
            S: cap://cal.example.com/calid33
            S: 2.3 Lookup resulted in too much data
            S: .
          
          Example #4: CS loses contact with directory server during
          UPNEXPAND
          
            C: UPNEXPAND group@example.com
            S: 2.0 group@example.com
            S: cap://cal.example.com/calid3
            S: cap://cal.example.com/calid5
          
          
            S: 2.4 Lost contact with directory server
            S: .
          
          
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          7.2 Application Protocol Commands
          
          
          7.2.1  Calendaring Commands
          
          The following methods provide a set of calendaring commands in
          CAP. Calendaring commands (or methods) allow a CU to directly
          manipulate a calendar.
          
          Calendar access rights can be granted for the more generalized
          access provided by the calendar commands.
          
          7.2.1.1   Restriction Tables
          
          Commands are sent to CAP servers encapsulated in iCalendar
          objects. The reply to these commands are also encapsulated in
          iCalendar objects. The restriction tables listed in the
          commands below describe the composition of the iCalendar data
          for these commands and replies.
          
          The Presence column uses the following values to assert
          whether a property is required, is optional and the number of
          times it may appear in the iCalendar object. A Comment may be
          provided to further clarify the presence criteria.
          
          The table below defines the values for the Presence column.
          
          
          Presence Value  Description
          --------------------------------------------------------------
          1         One instance MUST be present
          1+        At least one instance MUST be present
          0         Instances of this property Must NOT be present
          0+        Multiple instances MAY be present
          0 or 1    Up to 1 instance of this property MAY be present
          --------------------------------------------------------------
          
          While the tables list every component and property, their
          purpose is not to define the meaning of the component or
          property.
          
          There will be a REQUEST-STATUS for each VCALENDAR and
          component created, modified, deleted, or requested. The number
          of REQUEST-STATUS values returned MUST be equal to the number
          of TARGETS times the number of objects in the command. The
          responses MUST be ordered first by TARGET then by the order of
          the objects as supplied in the command.
          
          
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          7.2.1.2   CREATE Method
          
          Arguments: none
          
          Data:    no specific data for this command
          
          Result:   2.0 - successfully created the component or calendar
                    6.0 - Permission denied
                    6.1 - Container(s) not found
                    6.2 - Calendar or component already exists
                    6.3 -
                    Bad args
          
          The CREATE method is used to create a new iCalendar object of
          type objtype. The property TARGET specifies the container(s)
          for the create. The type of object wrapped inside of the
          VCALENDAR/CREATE object is the object type(s) being created.
          When creating a new calendar at the top level, the CSID is
          specified. Otherwise the container will be a CalID.
          
          Restriction table
          
          
          Component/Property     Presence Comment
          -------------------    -------- -----------------------------
          VCAP                   1+       The CUA can send up
                                          PIPELINE commands
                                          without processing a
                                          response
          
          . VERSION              1        MUST be 2.0
          . [IANA-PROP]          0+       any IANA registered
                                          property
          
          . VCOMMAND             1        MUST at least one container
                                          (VCALENDAR, VCAR, VQUERY,
                                          VEVENT, VTODO, VJOURNAL)
          . . CMDID              0 or 1   If CMDID is not supplied,
                                          then there must not be
                                          pending replies to previous
                                          command.
          
          . . [IANA-PROP]        0+       any IANA registered
                                          property
          . . METHOD             1        MUST be CREATE.
          . . TARGET             1+       MUST be the CSID or CALID
          
          . . VCALENDAR          0+
          
          
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          . . . CALMASTER        0 or 1
          . . . NAME             0 or 1
          . . . OWNER            1+
          . . . RELCALID         1
          . . . TZID             0 or 1
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          . . VCAR               0+
          . . . CARID            0 or 1
          . . . DENY             0+       Note, there must be at
                                          least one GRANT or DENY
                                          within the VCAR.
          . . . GRANT            0+       Note, there must be at
                                          least one GRANT or DENY
                                          within the VCAR.
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          . . VQUERY             0+
          . . . EXPAND           0 or 1
          . . . MAXRESULTS       0 or 1
          . . . MAXSIZE          0 or 1
          . . . QUERYNAME        1
          . . . QUERY            1
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          . . VEVENT             0+
          . . . ATTENDEE         0+
          . . . SEQUENCE         0 or 1   MUST be present if value is
                                          greater than 0,
                                          MAY be present if 0
          . . . SUMMARY          1        Can be null
          . . . UID              1
          
          . . . ATTACH           0+
          . . . CATEGORIES       0 or 1
          . . . CLASS            0 or 1
          . . . COMMENT          0 or 1
          . . . CONTACT          0+
          . . . CREATED          0 or 1
          . . . DESCRIPTION      0 or 1   Can be null
          . . . DTEND            0 or 1   if present DURATION MUST
                                          NOT be present
          . . . DTSTAMP          1
          . . . DTSTART          1
          . . . DURATION         0 or 1   if present DTEND MUST NOT
                                          be present
          
          
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          . . . EXDATE           0+
          . . . EXRULE           0+
          . . . GEO              0 or 1
          . . . LAST-MODIFIED    0 or 1
          . . . LOCATION         0 or 1
          . . . METHOD           1        <<placeholder. it may move
                                          to meta-info>>
          . . . ORGANIZER        1
          . . . PRIORITY         0 or 1
          . . . RDATE            0+
          . . . RECURRENCE-ID    0 or 1   only if referring to an
                                          instance of a recurring
                                          calendar component.
                                          Otherwise it MUST NOT be
                                          present.
          . . . RELATED-TO       0+
          . . . REQUEST-STATUS   0+
          . . . RESOURCES        0 or 1   This property MAY contain a
                                          list of values
          . . . RRULE            0+
          . . . STATUS           0 or 1
          . . . TRANSP           0 or 1
          . . . URL              0 or 1
          . . . X-PROPERTY       0+
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          . . . VALARM           0+
          . . . . ACTION         1
          . . . . ALARMID        0 or 1   MUST be 1 if multiple
                                          VALARMs are present in
                                          same component.
          . . . . ATTACH         0+
          . . . . DESCRIPTION    0 or 1
          . . . . DURATION       0 or 1  if present REPEAT MUST be
                                         present
          . . . . REPEAT         0 or 1  if present DURATION MUST be
                                         present
          . . . . SUMMARY        0 or 1
          . . . . TRIGGER        1
          . . . . X-PROPERTY     0+
          . . . . [IANA-PROP]    0+      any IANA registered property
          
          
          . . VTODO              0+
          . . . ATTENDEE         0+
          . . . SEQUENCE         0 or 1  MUST be present if value is
                                         greater than 0, MAY be
                                         present if 0
          
          
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          . . . SUMMARY          1       Can be null.
          . . . UID              1
          
          . . . ATTACH           0+
          . . . CATEGORIES       0 or 1  This property may contain a
                                         list of values
          . . . CLASS            0 or 1
          . . . COMMENT          0 or 1
          . . . CONTACT          0+
          . . . CREATED          0 or 1
          . . . DESCRIPTION      0 or 1  Can be null
          . . . DTSTAMP          1
          . . . DTSTART          1
          . . . DUE              0 or 1  If present DURATION MUST NOT
                                         be present
          . . . DURATION         0 or 1  If present DUE MUST NOT be
                                         present
          . . . EXDATE           0+
          . . . EXRULE           0+
          . . . GEO              0 or 1
          . . . LAST-MODIFIED    0 or 1
          . . . LOCATION         0 or 1
          . . . METHOD           1       <<placeholder. it may move
                                         to meta-info>>
          . . . ORGANIZER        1
          . . . PRIORITY         1
          . . . PERCENT-COMPLETE 0 or 1
          . . . RDATE            0+
          . . . RECURRENCE-ID    0 or 1  MUST only if referring to an
                                         instance of a recurring
                                         calendar component.
                                         Otherwise it MUST NOT be
                                         present.
          . . . RELATED-TO       0+
          . . . REQUEST-STATUS   0
          . . . RESOURCES        0 or 1  This property may contain a
                                         list of values
          . . . RRULE            0+
          . . . STATUS           0 or 1  MAY be one of COMPLETED,
                                         NEEDS-ACTION,
                                         IN-PROCESS, CANCELLED
          . . . URL              0 or 1
          
          . . . X-PROPERTY       0+
          . . . [IANA-PROP]      0+      any IANA registered property
          
          . . . VALARM           0+
          . . . . ACTION         1
          . . . . ALARMID        0 or 1  MUST be 1 if multiple
          
          
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                                         VALARMs are present in
                                         same component.
          . . . . ATTACH         0+
          . . . . DESCRIPTION    0 or 1
          . . . . DURATION       0 or 1  if present REPEAT MUST be
                                         present
          . . . . REPEAT         0 or 1  if present DURATION MUST be
                                         present
          . . . . SUMMARY        0 or 1
          . . . . TRIGGER        1
          . . . . X-PROPERTY     0+
          . . . . [IANA-PROP]    0+      any IANA registered property
          
          
          . . VJOURNAL           0+
          . . . ATTENDEE         0
          . . . DESCRIPTION      1    Can be null.
          . . . DTSTAMP          1
          . . . DTSTART          1
          . . . ORGANIZER        1
          . . . UID              1
          
          . . . ATTACH           0+
          . . . CATEGORIES       0 or 1 This property MAY contain a list
          of values
          . . . CLASS            0 or 1
          . . . COMMENT          0 or 1
          . . . CONTACT          0+
          . . . CREATED          0 or 1
          . . . EXDATE           0+
          . . . EXRULE           0+
          . . . LAST-MODIFIED    0 or 1
          . . . METHOD           1        <<placeholder. it may move
                                          to meta-info>>
          . . . RDATE            0+
          . . . RECURRENCE-ID    0 or 1   MUST only if referring to
                                          an instance of a recurring
                                          calendar component.
                                          Otherwise it MUST NOT be
                                          present.
          . . . RELATED-TO       0+
          . . . RRULE            0+
          . . . SEQUENCE         0 or 1   MUST be present if
                                          non-zero. MAY be
                                          present if zero.
          . . . STATUS           0 or 1
          . . . SUMMARY          0 or 1   Can be null
          . . . URL              0 or 1
          . . . X-PROPERTY       0+
          
          
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          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          
          . . VFREEBUSY          0
          
          . . VTIMEZONE          0+       MUST be present if any
                                          date/time refers to a
                                          timezone
          . . . DAYLIGHT         0+       MUST be one or more of
                                          either STANDARD or
                                          DAYLIGHT
          . . . . . COMMENT      0 or 1
          . . . . . DTSTART      1
          . . . . . RDATE        0+       if present RRULE MUST NOT
                                          be present
          . . . . . RRULE        0+       if present RDATE MUST NOT
                                          be present
          . . . . . TZNAME       0 or 1
          . . . . . TZOFFSET     1
          . . . . . TZOFFSETFROM 1
          . . . . . TZOFFSETTO   1
          . . . . . X-PROPERTY   0+
          . . . . . [IANA-PROP]  0+       any IANA registered
                                          property
          . . . LAST-MODIFIED    0 or 1
          . . . STANDARD         0+
          . . . . . COMMENT      0 or 1
          . . . . . DTSTART      1
          . . . . . RDATE        0+       if present RRULE MUST NOT
                                          be present
          . . . . . RRULE        0+       if present RDATE MUST NOT
                                          be present
          . . . . . TZNAME       0 or 1
          . . . . . TZOFFSETFROM 1
          . . . . . TZOFFSETTO   1
          . . . . . X-PROPERTY   0+
          . . . . . [IANA-PROP]  0+       any IANA registered property
          . . . TZID             1
          . . . TZURL            0 or 1
          . . . X-PROPERTY       0+
          . . . [IANA-PROP]      0+       any IANA registered property
          
          
          
          Server Restriction Table for the CREATE command
          
          Component/Property  Presence Comment
          ------------------- -------- -------------------------------
          
          
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          VCAP                   1+
          . VCALENDAR            1+
          . . TARGET             1
          
          . . VERSION            1        MUST be 2.0
          
          . . CMDID              0 or 1   MUST be returned if the
                                          request contained
                                          a CMDID
          . . REQUEST-STATUS     0        if not creating a calendar
                                 1+       if creating a calendar
          
          . . . VCAR             0+
          . . . . REQUEST-STATUS   1+
          . . . . *              0        No other VCAR properties
                                          are present
          .
          . . . VCOMMAND         0
          
          . . . VEVENT           0+
          . . . . REQUEST-STATUS    1+
          . . . . *              0        No other VEVENT properties
                                          are present
          . . . . VALARM         0        if VEVENT was successfully
                                          saved
                                 1+       if there were errors saving
                                          alarms
          . . . . . REQUEST-STATUS  1+
          
          . . . VFREEBUSY        0+
          . . . . REQUEST-STATUS    1+
          . . . . *              0        No other VFREEBUSY
                                          properties are present
          
          . . . VJOURNAL         0+
          . . . . REQUEST-STATUS    1+
          . . . . *              0        No other VJOURNAL
                                          properties are present
          
          . . . VQUERY           0+
          . . . . REQUEST-STATUS    1+
          . . . . *              0        No other VQUERY properties
                                          are present
          
          . . . VTODO            0+
          . . . . REQUEST-STATUS    1+
          . . . . *              0        No other VTODO properties
                                          are present
          
          
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          . . . . VALARM         0        if VTODO was successfully
                                          saved
                                 1+       if there were errors saving
                                          alarms
          . . . . . REQUEST-STATUS   1+
          
          
          7.2.1.2.1       Creating New Calendars
          
          Example to create two new calendars different containers. In
          the following example, the client is in the Authenticated
          state with CS cal.example.com.
          
            C: SENDDATA
            C: CONTENT-TYPE: text/calendar; method=CREATE;
            C:   component=VCOMMAND
            C: Content-Transfer-Encoding:7bit
            C:
            C: BEGIN:VCAP
            C: VERSION:2.1
            C: BEGIN:VCOMMAND
            C: METHOD:CREATE
            C: TARGET:cap://cal.example.com/
            C: TARGET:relcal4
            C: BEGIN:VCALENDAR
            C: RELCALID:relcalz1
            C: NAME:CHARSET=us-ascii;LANGUAGE=EN-us:Bill's Soccer Team
            C: OWNER:bill
            C: CALMASTER:mailto:bill@example.com
            C: TZID:US_PST
            C: BEGIN:VCAR
            C: CARID:12345
            C: GRANT:UPN=bill;ACTION=*;OBJECT=*
            C: END:VCAR
            C: END:VCALENDAR
            C: BEGIN:VCALENDAR
            C: RELCALID:relcalz2
            C: NAME:CHARSET=us-ascii;LANGUAGE=EN-us:Mary's personal
            C:   calendar
            C: OWNER:mary
            C: CALMASTER:mailto:mary@example.com
            C: TZID:US_PST
            C: BEGIN:VCAR
            C: CARID:12346
            C: GRANT:UPN=mary;ACTION=*;OBJECT=*
            C: END:VCAR
            C: END:VCALENDAR
            C: END:VCOMMAND
            C: END:VCAP
          
          
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            C: .
            S: 2.0
            S: Content-Type:text/calendar; method=RESPONSE;
            S:   OPTINFO="CMDID:abcde"
            #  This 2.0 is the transport reply status and ends with a
            #  CRLF.CRLF (below)
            S: BEGIN:VCAP
            S: METHOD:RESPONSE
            S: TARGET:cap://cal.example.com/
            S: REQUEST-STATUS:2.0
            S: END:VCAP
            S: BEGIN:VCAP
            S: METHOD:RESPONSE
            S: REQUEST-STATUS:2.0
            S: END:VCAP
            S: .
          
          
          Example to create a new component.
          
            C: SENDDATA
            C: Content-Type:text/calendar; method=CREATE;
            C:   charset=US-ASCII
            C: Content-Transfer-Encoding:7bit
            C:
            C: BEGIN:VCAP
            C: VERSION:2.1
            C: CMDID:abcde
            C: BEGIN:VCOMMAND
            C: METHOD:CREATE
            C: TARGET:cap://cal.example.com/relcal1
            C: TARGET:relcal2
            C: BEGIN:VEVENT
          
            C: DTSTART:99990307T180000Z
            C: UID:abcd12345
            C: DTEND:99990307T190000Z
            C: SUMMARY:Important Meeting
            C: END:VEVENT
            C: END:VCOMMAND
            C: END:VCAP
            C: .
            S: 2.0
            S: Content-Type:text/calendar; method=RESPONSE;
            S:   OPTINFO="CMDID:abcde"
            S:
            S: BEGIN:VCAP
            S: VERSION:2.1
            S: CMDID:abcde
          
          
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            S: METHOD:RESPONSE
            S: BEGIN:VEVENT
            S: TARGET::cap://cal.example.com/relcal1
            S: REQUEST-STATUS:2.9
            S: END:VEVENT
            S: BEGIN:VEVENT
            S: REQUEST-STATUS:2.9
            S: REQUEST-STATUS:2.10
            S: END:VEVENT
            S: END:VCAP
            S: .
          
          The response contains the calendar (CALID) and UID of the
          component so that the CUA can match up the TARGET from
          multiple objects created on multiple calendards (TARGETs).
          
          7.2.1.3   DELETE Method
          
          Arguments: none
          
          Data:    no specific data for this command
          
          Result:   2.0 - successfully deleted the component or calendar
                    Permission
                    Calendar or component not found
                    Bad args
                    Container(s) not found
          
          The DELETE method is used to delete a calendar or component.
          The TARGET properties specify the container(s) for the delete.
          When deleting a calendar at the top level, the CSID is
          specified. Otherwise the   container will be a CalID.
          
          Restriction Table
          
          Component/Property    Presence Comment
          -------------------   -------- ---------------------------
          VCAP                  1+       The CUA can send up
                                         PIPELINE commands
                                         without processing a
                                         response
          
          
           VERSION              1        MUST be 2.0
          
           VCOMMAND             1
            CMDID               0 or 1   If CMDID is not supplied,
                                         then there must
                                         not be pending replies to
          
          
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                                         previous command.
            METHOD              1        MUST be DELETE.
            TARGET              1+       MUST be a the CSID or CALID
          
            VQUERY              0+
             EXPAND             0    ?
             MAXRESULTS         0 or 1   Limit the solution set to
                                         no more than this many
                                         entries.
             MAXSIZE            0    ?
             QUERYNAME          1        Name by which this query is
                                         referenced
             QUERY              1        The query
          
          
          Server Restriction Table for the DELETE command
          
          Component/Property  Presence Comment
          ------------------- -------- -----------------------------
          
          VCAP                1+
          TARGET              1
          
          VERSION             1        MUST be 2.0
          
          CMDID               0 or 1   MUST be returned if the
                                       request contained a CMDID
          
          VCALENDAR                    Only if VCALENDARs were
                                       deleted
            REQUEST-STATUS    1
            *                 1+       No other VALARM properties
                                       are present
          
          VALARM              0+       Only if VALARM components
                                       were deleted
            REQUEST-STATUS    1
            *                 0        No other VALARM properties
                                       are present
          
          VCAR                0+       Only if VCAR components were
                                       deleted
            REQUEST-STATUS    1
            *                 0        No other VCAR properties are
                                       present
          
          VEVENT              0+       Only if VEVENT components
                                       were deleted
            REQUEST-STATUS    1+
          
          
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            *                 0        No other VEVENT properties
                                       are present
          
          VFREEBUSY           0
            REQUEST-STATUS    1+
            *                 0        No other VFREEBUSY properties
                                       are present
          
          VJOURNAL            0+       Only if VJOURNAL components
                                       were deleted
            REQUEST-STATUS    1+
            *                 0        No other VJOURNAL properties
                                       are present
          
          VQUERY              0+       Only if VQUERY components
                                       were deleted
            REQUEST-STATUS    1+
            *                 0        No other VQUERY properties
                                       are present
          
          VTIMEZONE           0+       Only if VTIMEZONE components
                                       were deleted
            REQUEST-STATUS    1+
            *                 0        No other VQUERY properties
                                       are present
          
          VTODO               0+       Only if VTODO components were
                                       deleted
            REQUEST-STATUS    1+
            *                 0        No other VTODO properties are
                                       present
          
          
          ----------------------------------------------------------
          
          [Editors note: Issues:
          
          - Currently CAP requires that the server return a response
          status. However, if there are multiple components deleted,
          should the UID also be returned?
          
          - VQUERY EXPAND and MAXSIZE parameters do not seem to apply to
          deletion?
          
          - Can one use DELETE to remove all VALARMs and VTIMEZONEs that
          match a certain search criteria and that belong to all
          components, event though VALARMs and VTIMEZONEs never exist as
          independent components? Or should one use MODIFY? If they can
          
          
          
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          be deleted, do we return the REQUEST-STATUS of their deletion
          in a VEVENT or separately?
          
          - In the example in CAP where a calendar is deleted all the
          server returns is 2.0, nothing else?
          
           - We should not be able to delete any VFREEBUSY components?
          
           - Can we delete multiple calendars?
          
           - Currently one can not delete a VCALENDAR and some other
          component in the same DELETE command. This seems OK. Anyone
          see any need to be able to do this?
          
           - Should the MAXRESULTS property of VQUERY apply to deletion?
          We can use it to delete only the first n components that
          match.
          ]
          
            Example to delete a VEVENT with UID 'abcd12345':
          
            C: SENDDATA
            C: Content-Type:text/calendar; method=DELETE;
          component=VCOMMAND
            C: Content-Transfer-Encoding:7bit
            C:
          
          C: BEGIN:VCAP
            C: BEGIN:VCOMMAND
            C: METHOD:DELETE
            C: TARGET:cap://cal.foo.com/bill
            C: BEGIN:VQUERY
            C: QUERY:SELECT UID FROM VEVENT WHERE UID = 'abcd12345'
            C: END:VQUERY
            C: END:VCOMMAND
            C: END:VCAP
            C: .
            S: 2.0
            S: Content-Type:text/calendar; method=DELETE;
            S:  component=VCOMMAND
            S:
            S: BEGIN:VCAP
            S: METHOD:RESPONSE
            S: BEGIN:VEVENT
            S: REQUEST-STATUS:2.0
            S: END:VEVENT
            S: END:VCAP
            S: .
          
          
          
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          And an example to delete the 'MrBill' calendar:
          
            C: SENDDATA
            C: Content-Type:text/calendar; method=DELETE;
            C:  component=VCOMMAND
            C: Content-Transfer-Encoding:7bit
            C:
            C: BEGIN:VCAP
            C: BEGIN:VCOMMAND
            C: METHOD:DELETE
            C: TARGET:cap://cal.foo.com/MrBill
            C: END:VCOMMAND
            C: END:VCAP
            C: .
            S: 2.0
            S: .
          
          
          7.2.1.4   GENERATEUID Method
          
          Arguments: Number of UIDs to generate.
          
          Data:      new uids
          
          Result:    2.0
          
          GENERATEUID returns one or more new unique identifier which
          MUST be unique on the server's calendar store. It is
          recommended that the return value be a globally unique id.
          
          Example:
          
          C: GENERATEUID 2
          
          S: 2.0 abcde1234567-asdf-lkhh abcde1234567-asdf-3455
          
          [EDITORS NOTE: this example needs work. It's not packaged
          right]
          
          
          7.2.1.5   MODIFY Method
          
          Arguments: none
          
          Data:     no specific data for this command
          
          Result:   2.0 - successfully modified the component or
                          calendar
                Permission
          
          
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                Calendar or component not found
                Bad args
                Container(s) not found
          
          The MODIFY method is used to change an existing calendar or
          component. TARGET specify the container(s) of the
          modification. When modifying a calendar at the top level, the
          CSID is specified. Otherwise the container will be a CalID.
          
          The format of the request is two or three containers inside of
          a VCOMMAND container:
          
            BEGIN:VCOMMAND
            [VQUERY]
            OLD-VALUES
            NEW-VALUES
            END:VCOMMAND
          
          If a VQUERY is present, then only objects matching the query
          results are modified.
          
          Restriction Table
          
          Component/Property     Presence Comment
          -------------------    -------- ---------------------------
          VCAP                   1+       The CUA can send up
                                          PIPELINE commands
                                          without processing a
                                          response
          
          
          . VERSION              1        MUST be 2.0
          . [IANA-PROP]          0+       any IANA registered
                                          property
          
          . VCOMMAND             1        MUST have at least one
                                          container (VCALENDAR,
                                          VCAR, VQUERY, VEVENT,
                                          VTODO, VJOURNAL)
          . . CMDID                0 or 1 If CMDID is not supplied,
                                          then there must
                                          not be pending replies to
                                          previous command.
          . . [IANA-PROP]        0+       any IANA registered
                                          property
          . . METHOD             1        MUST be MODIFY
          . . TARGET             1+       MUST be the CALID
          
          . . VCALENDAR          0+
          
          
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          . . . CALMASTER        0 or 1
          . . . NAME             0 or 1
          . . . OWNER            1+
          . . . RELCALID         1
          . . . TZID             0 or 1
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          . . VCAR               0+
          . . . CARID            0 or 1
          . . . DENY             0+       Note, there must be at
                                          least one GRANT or DENY
                                          within the VCAR.
          . . . GRANT            0+       Note, there must be at
                                          least one GRANT or DENY
                                          within the VCAR.
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          . . VQUERY             0+
          . . . EXPAND           0 or 1
          . . . MAXRESULTS       0 or 1
          . . . MAXSIZE          0 or 1
          . . . QUERYNAME        1
          . . . QUERY            1
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          . . VEVENT             0+
          . . . ATTENDEE         0+
          . . . SEQUENCE         0 or 1   MUST be present if value is
                                          greater than 0,
                                          MAY be present if 0
          . . . SUMMARY          1        Can be null
          . . . UID              1
          
          . . . ATTACH           0+
          . . . CATEGORIES       0 or 1
          . . . CLASS            0 or 1
          . . . COMMENT          0 or 1
          . . . CONTACT          0+
          . . . CREATED          0 or 1
          . . . DESCRIPTION      0 or 1   Can be null
          . . . DTEND            0 or 1   if present DURATION MUST
                                          NOT be present
          . . . DTSTAMP          1
          . . . DTSTART          1
          . . . DURATION         0 or 1   if present DTEND MUST NOT
                                          be present
          
          
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          . . . EXDATE           0+
          . . . EXRULE           0+
          . . . GEO              0 or 1
          . . . LAST-MODIFIED    0 or 1
          . . . LOCATION         0 or 1
          . . . METHOD           1         <<placeholder. it may move
                                             to meta-info>>
          . . . ORGANIZER        1
          . . . PRIORITY         0 or 1
          . . . RDATE            0+
          . . . RECURRENCE-ID    0 or 1   only if referring to an
                                          instance of a recurring
                                          calendar component.
                                          Otherwise it MUST NOT be
                                          present.
          . . . RELATED-TO       0+
          . . . REQUEST-STATUS   0+
          . . . RESOURCES        0 or 1   This property MAY contain a
                                          list of values
          . . . RRULE            0+
          . . . STATUS           0 or 1
          . . . TRANSP           0 or 1
          . . . URL              0 or 1
          . . . X-PROPERTY       0+
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          . . . VALARM           0+
          . . . . ACTION         1
          . . . . ALARMID        0 or 1   MUST be 1 if multiple
                                          VALARMs are present in same
                                          component.
          . . . . ATTACH         0+
          . . . . DESCRIPTION    0 or 1
          . . . . DURATION       0 or 1   if present REPEAT MUST be
                                          present
          . . . . REPEAT         0 or 1   if present DURATION MUST be
                                          present
          . . . . SUMMARY        0 or 1
          . . . . TRIGGER        1
          . . . . X-PROPERTY     0+
          . . . . [IANA-PROP]    0+       any IANA registered
                                          property
          
          
          . . VTODO              0+
          . . . ATTENDEE         0+
          . . . SEQUENCE         0 or 1   MUST be present if value is
                                          greater than 0, MAY be
          
          
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                                          present if 0
          . . . SUMMARY          1        Can be null.
          . . . UID              1
          
          . . . ATTACH           0+
          . . . CATEGORIES       0 or 1   This property may contain a
                                          list of values
          . . . CLASS            0 or 1
          . . . COMMENT          0 or 1
          . . . CONTACT          0+
          . . . CREATED          0 or 1
          . . . DESCRIPTION      0 or 1   Can be null
          . . . DTSTAMP          1
          . . . DTSTART          1
          . . . DUE              0 or 1   If present DURATION MUST
                                          NOT be present
          . . . DURATION         0 or 1   If present DUE MUST NOT be
                                          present
          . . . EXDATE           0+
          . . . EXRULE           0+
          . . . GEO              0 or 1
          . . . LAST-MODIFIED    0 or 1
          . . . LOCATION         0 or 1
          . . . METHOD           1        <<placeholder. it may move
                                          to meta-info>>
          . . . ORGANIZER        1
          . . . PRIORITY         1
          . . . PERCENT-COMPLETE 0 or 1
          . . . RDATE            0+
          . . . RECURRENCE-ID    0 or 1   MUST only if referring to
                                          an instance of a recurring
                                          calendar component.
                                          Otherwise it MUST NOT
                                          be present.
          . . . RELATED-TO       0+
          . . . REQUEST-STATUS   0
          . . . RESOURCES        0 or 1   This property may contain a
                                          list of values
          . . . RRULE            0+
          . . . STATUS           0 or 1   MAY be one of COMPLETED,
                                          NEEDS-ACTION,
                                          IN-PROCESS, CANCELLED
          . . . URL              0 or 1
          
          . . . X-PROPERTY       0+
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          . . . VALARM           0+
          
          
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          . . . . ACTION         1
          . . . . ALARMID        0 or 1   MUST be 1 if multiple
                                          VALARMs are present in
                                          same component.
          . . . . ATTACH         0+
          . . . . DESCRIPTION    0 or 1
          . . . . DURATION       0 or 1   if present REPEAT MUST be
                                          present
          . . . . REPEAT         0 or 1   if present DURATION MUST be
                                          present
          . . . . SUMMARY        0 or 1
          . . . . TRIGGER        1
          . . . . X-PROPERTY     0+
          . . . . [IANA-PROP]    0+       any IANA registered
                                          property
          
          
          . . VJOURNAL           0+
          . . . ATTENDEE         0
          . . . DESCRIPTION      1        Can be null.
          . . . DTSTAMP          1
          . . . DTSTART          1
          . . . ORGANIZER        1
          . . . UID              1
          
          . . . ATTACH           0+
          . . . CATEGORIES       0 or 1   This property MAY contain a
                                          list of values
          . . . CLASS            0 or 1
          . . . COMMENT          0 or 1
          . . . CONTACT          0+
          . . . CREATED          0 or 1
          . . . EXDATE           0+
          . . . EXRULE           0+
          . . . LAST-MODIFIED    0 or 1
          . . . METHOD           1        <<placeholder. it may move
                                          to meta-info>>
          . . . RDATE            0+
          . . . RECURRENCE-ID    0 or 1   MUST only if referring to
          
                                          an instance of a recurring
                                          calendar component.
                                          Otherwise it MUST NOT be
                                          present.
          . . . RELATED-TO       0+
          . . . RRULE            0+
          . . . SEQUENCE         0 or 1   MUST be present if non-
                                          zero. MAY be
          . . . . .                       present if zero.
          
          
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          . . . STATUS           0 or 1
          . . . SUMMARY          0 or 1   Can be null
          . . . URL              0 or 1
          . . . X-PROPERTY       0+
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          
          . . VFREEBUSY          0
          
          . . VTIMEZONE          0+       MUST be present if any
                                          date/time refers
                                          to a timezone
          . . . DAYLIGHT         0+       MUST be one or more of
                                          either STANDARD
                                          or DAYLIGHT
          . . . . . COMMENT      0 or 1
          . . . . . DTSTART      1
          . . . . . RDATE        0+       if present RRULE MUST NOT
                                          be present
          . . . . . RRULE        0+       if present RDATE MUST NOT
                                          be present
          . . . . . TZNAME       0 or 1
          . . . . . TZOFFSET     1
          . . . . . TZOFFSETFROM 1
          . . . . . TZOFFSETTO   1
          . . . . . X-PROPERTY   0+
          . . . . . [IANA-PROP]  0+       any IANA registered
                                          property
          . . . LAST-MODIFIED    0 or 1
          . . . STANDARD         0+
          . . . . . COMMENT      0 or 1
          . . . . . DTSTART      1
          . . . . . RDATE        0+       if present RRULE MUST NOT
                                          be present
          . . . . . RRULE        0+       if present RDATE MUST NOT
                                          be present
          . . . . . TZNAME       0 or 1
          . . . . . TZOFFSETFROM 1
          . . . . . TZOFFSETTO   1
          . . . . . X-PROPERTY   0+
          . . . . . [IANA-PROP]  0+       any IANA registered
                                          property
          . . . TZID             1
          . . . TZURL            0 or 1
          . . . X-PROPERTY       0+
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          
          
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          Server Restriction Table for the MODIFY command
          
          Component/Property    Presence   Comment
          --------------------- --------   --------------------------
          
          VCAP                  1+
          . VCALENDAR           1+
          . . TARGET            1
          
          . . VERSION           1        MUST be 2.0
          
          . . CMDID             0 or 1   MUST be returned if the
                                         request contained a CMDID
          . . REQUEST-STATUS    0        if not creating a calendar
                                1+       if creating a calendar
          
          . . . VCAR            0+
          . . . . REQUEST-STATUS    1+
          . . . . *             0        No other VCAR properties are
                                         present
          .
          . . . VCOMMAND        0
          
          . . . VEVENT         0+
          . . . . REQUEST-STATUS    1+
          . . . . *            0         No other VEVENT properties
                                         are present
          . . . . VALARM       0         if VEVENT was successfully
                                         saved
                               1+        if there were errors saving
                                         alarms
          . . . . . REQUEST-STATUS   1+
          
          
          . . . VFREEBUSY       0+
          . . . . REQUEST-STATUS    1+
          . . . . *             0        No other VFREEBUSY
                                         properties are
                                         present
          
          . . . VJOURNAL        0+
          . . . . REQUEST-STATUS    1+
          . . . . *             0        No other VJOURNAL properties
                                         are present
          
          . . . VQUERY          0+
          . . . . REQUEST-STATUS    1+
          
          
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          . . . . *             0        No other VQUERY properties
                                         are present
          
          . . . VTODO           0+
          . . . . REQUEST-STATUS    1+
          . . . . *             0        No other VTODO properties
                                         are present
          . . . . VALARM        0        if VTODO was successfully
                                         saved
                                1+       if there were errors saving
                                         alarms
          . . . . . REQUEST-STATUS   1+
          
          
          [EditorËs notes: Issues:
          freebusy - a cap server should dynamically calculate freebusy
          information we recommend that you cannot create, modify, or
          delete  freebusy composers ]
          
          In the example below, the start and end time of the event with
          UID abcd12345 is changed and the LOCATION property is removed.
          
            C: SENDDATA
            C: Content-type:text/calendar; Method=MODIFY;
            C:  Component=VCOMMAND
            C:
            C: BEGIN:VCAP
            C: VERSION:2.1
            C: BEGIN:VCOMMAND
            C: METHOD:MODIFY
            C: TARGET:relcal2
            C: BEGIN:VCOMMAND
            C: BEGIN:VQUERY
            C: QUERY:SELECT UID FROM VEVENT WHERE UID = 'abcd12345'
            C: END:VQUERY
            C: BEGIN:VEVENT
            C: DTSTART:19990421T160000Z
            C: DTEND:19990421T163000Z
            C: LOCATION:Joe's Diner
            C: END:VCOMMAND
            C: END:VEVENT
          
            C: BEGIN:VEVENT
            C: DTSTART:19990421T160000Z
            C: DTEND:19990421T163000Z
            C: END:VEVENT
            C: END:VCOMMAND
            C: END:VCAP
            C: .
          
          
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            S: 2.0 cap://cal.example.com/relcal2
          
          And in this example, all instances of "Building 6" are
          replaced by "New office lobby" in VEVENTs:
          
            C: SENDDATA
            C: Content-type:text/calendar; Method=MODIFY;
            C:  Component=VCOMMAND
            C:
            C: BEGIN:VCAP
            C: VERSION:2.1
            C: BEGIN:VCOMMAND
            C: METHOD:MODIFY
            C: TARGET:relcal2
            C: BEGIN:VCOMMAND
            C: BEGIN:VEVENT
            C: LOCATION:Building 6
            C: END:VEVENT
            C: BEGIN:VEVENT
            C: LOCATION:New office lobby
            C: END:VEVENT
            C: END:VCOMMAND
            C: END:VCOMMAND
            C: END:VCAP
            C: .
            S: 2.0 cap://cal.example.com/relcal2
          
          
          7.2.1.6   MOVE Method
          
          Arguments: ContainerId
          
          Data:      data as described below
          
          Result:    2.0 - success
                     2.2 - will attempt operation on the remote CAP
                           server
                     Permission
                     Calendar already exists
                     Bad args
                     Parent Calendar(s) not found
          
          This method is used to move a calendar within the CS's
          hierarchy of calendars.
          
          Restriction Table
          Component/Property     Presence  Comment
          -------------------    -------- ---------------------
          VCAP                   1+       The CUA can send up
          
          
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                                          PIPELINE commands without
                                          processing a response
          
          . VERSION              1        MUST be 2.0
          
          . VCOMMAND             1        MUST have at least one
                                          VCALENDAR
          
          . . CMDID              0 or 1   If CMDID is not supplied,
                                          then there must not be
                                          pending replies to
                                          previous command.
          
          . . [IANA-PROP]        0+       any IANA registered
                                          property
          
          . . METHOD             1        MUST be MOVE.
          . . TARGET             1        MUST be a the CSID or
                                          CALID
          
          . . VCALENDAR          1+
          . . . CALMASTER        0
          . . . NAME             0
          . . . OWNER            0
          . . . RELCALID         1
          . . . TZID             0
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          
          Server Restriction Table for the MOVE command
          
          Component/Property  Presence Comment
          ------------------- -------- -----------------------------
          
          VCAP                1+
          
          . VCALENDAR         1+
          
          . . TARGET          1
          . . VERSION         1        MUST be 2.0
          
          . . CMDID           0 or 1   MUST be returned if the
                                       request contained
                                       a CMDID
          . . REQUEST-STATUS  1+
          
          ---------------------------------------------------------
          
          
          
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          [Editors note: Issues:
           1) Should one be able to move a calendar owned by person X
          into a calendar owned by person Y. (Can these such rights be
          specified in VCARs?)
           2) Should we also be able to move components from one
          calendar to another? What if the calendars are owned by
          different users? (With components one can do a copy, then
          delete the original.)
           3) There was very little information about MOVE in CAP. Why
          was it added? Was there some major need for it?
           4) Can one move multiple calendars into one calendar?
          ]
          
          7.2.1.7   NOOP Method
          
          Arguments: none
          
          Data:      none
          
          Result:    2.0 - success
          
          This method does nothing. It can be sent to the server
          periodically to request that the CS not time out the session.
          
          
          7.2.1.8   READ Method
          
          Arguments: ContainerId
          
          Data:      data as described below
          
          Result:    2.0 -
                         - successful and the requested data follows
                     2.2 - will attempt read on the remote CAP server
                     Permission
                     Bad args
          
          Restriction Table
          
          Component/Property     Presence Comment
          -------------------    -------- ---------------------------
          VCAP                   1+       The CUA can send
                                          PIPELINE commands
                                          without processing a
                                          response
          
          
          . VERSION              1        MUST be 2.0
          . [IANA-PROP]          0+       any IANA registered
                                          property
          
          
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          . VCOMMAND             1        MUST have at least one
                                          container (VCALENDAR,
                                          VCAR, VQUERY, VEVENT,
                                          VTODO, VJOURNAL)
          . . CMDID              0 or 1   If CMDID is not supplied,
                                          then there must not be pending
                                          replies to previous command.
          . . [IANA-PROP]        0+       any IANA registered
                                          property
          . . METHOD             1        MUST be READ
          . . TARGET             1+       MUST be the CALID
          
          . . VCALENDAR          0+
          . . . CALMASTER        0 or 1
          . . . NAME             0 or 1
          . . . OWNER            1+
          . . . RELCALID         1
          . . . TZID             0 or 1
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          . . VCAR               0
          
          . . VQUERY             1
          . . . EXPAND           0 or 1
          . . . MAXRESULTS       0 or 1
          . . . MAXSIZE          0 or 1
          . . . QUERYNAME        1
          . . . QUERY            1
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          . . VEVENT             0
          . . VTODO              0
          . . VJOURNAL           0
          . . VFREEBUSY          0
          
          . . VTIMEZONE          0+       MUST be present if any
                                          date/time refers
                                          to a timezone
          . . . DAYLIGHT         0+       MUST be one or more of
                                          either STANDARD
                                          or DAYLIGHT
          . . . . . COMMENT      0 or 1
          . . . . . DTSTART      1
          . . . . . RDATE        0+       if present RRULE MUST NOT
                                          be present
          . . . . . RRULE        0+       if present RDATE MUST NOT
          
          
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                                          be present
          . . . . . TZNAME       0 or 1
          . . . . . TZOFFSET     1
          . . . . . TZOFFSETFROM 1
          . . . . . TZOFFSETTO   1
          . . . . . X-PROPERTY   0+
          . . . . . [IANA-PROP]  0+       any IANA registered
                                          property
          . . . LAST-MODIFIED    0 or 1
          . . . STANDARD         0+
          . . . . . COMMENT      0 or 1
          . . . . . DTSTART      1
          . . . . . RDATE        0+       if present RRULE MUST NOT
                                          be present
          . . . . . RRULE        0+       if present RDATE MUST NOT
                                          be present
          . . . . . TZNAME       0 or 1
          . . . . . TZOFFSETFROM 1
          . . . . . TZOFFSETTO   1
          . . . . . X-PROPERTY   0+
          . . . . . [IANA-PROP]  0+       any IANA registered
                                          property
          . . . TZID             1
          . . . TZURL            0 or 1
          . . . X-PROPERTY       0+
          . . . [IANA-PROP]      0+       any IANA registered
                                          property
          
          
          
          Server Restriction Table for the READ command
          
          Component/Property    Presence Comment
          --------------------- -------- --------------------------
          
          VCAP                    1+
          . VCALENDAR             1+
          . . TARGET              1
          
          . . VERSION             1      MUST be 2.0
          
          . . CMDID               0 or 1 MUST be returned if the
                                         request contained a CMDID
          . . REQUEST-STATUS      0      if not creating a calendar
                                  1+     if creating a calendar
          
          . . . VCAR              0+
          . . . . REQUEST-STATUS  1+
          . . . . *               0      No other VCAR properties are
          
          
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                                         present
          .
          . . . VCOMMAND          0
          
          . . . VEVENT            0+
          . . . . REQUEST-STATUS  1+
          . . . . *               0      No other VEVENT properties
                                         are present
          . . . . VALARM          0      if VEVENT was successfully
                                         saved
                                  1+     if there were errors saving
                                         alarms
          . . . . . REQUEST-STATUS 1+
          
          
          . . . VFREEBUSY         0+
          . . . . REQUEST-STATUS  1+
          . . . . *               0      No other VFREEBUSY
                                         properties are
                                         present
          
          . . . VJOURNAL          0+
          . . . . REQUEST-STATUS  1+
          . . . . *               0      No other VJOURNAL properties
                                         are present
          
          . . . VQUERY            0+
          . . . . REQUEST-STATUS  1+
          . . . . *               0      No other VQUERY properties
                                         are present
          
          . . . VTODO             0+
          . . . . REQUEST-STATUS  1+
          . . . . *               0      No other VTODO properties
                                         are present
          . . . . VALARM          0      if VTODO was successfully
                                         saved
                                  1+     if there were errors saving
                                         alarms
          . . . . . REQUEST-STATUS 1+
          
          
          Read Events
          
          In the example below events on March 10,1999 between 080000Z
          and 190000Z are read. In this case only 4 properties for each
          event are returned. Two calendars are specified. Only booked
          (vs scheduled) entries are to be returned. The first returns
          
          
          
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          two VEVENTS that match in that TARGET, the second result
          returns only one VEVENT for the second TARGET.
          
            C: SENDDATA
            C: Content-type:text/calendar; Method=READ; Component=VQUERY
            C:
            C: BEGIN:VCAP
            C: VERSION:2.1
            C: BEGIN:VCOMMAND
            C: METHOD:READ
            C: CMDID:xyz12345
            C: TARGET:relcal2
            C: TARGET:cap://bobo.ex.com/relcal3
            C: BEGIN:VQUERY
            C: QUERY:SELECT DTSTART,DTEND,SUMMARY,UID
                FROM VEVENT
                WHERE DTEND >= '19990310T080000Z'
                AND DTSTART <= '19990310T190000Z'
                AND METHOD = 'CREATE'
            C: END:VQUERY
            C: END:VCOMMAND
            C: END:VCAP
            C: .
            S: 2.0 cap://cal.example.com/relcal2
            S: Content-type:text/calendar; Method=RESPONSE;
                Optinfo=VERSION:2.1
            S: Content-Transfer-Encoding: 7bit
            S:
            S: BEGIN:VCAP
            S: VERSION:2.1
            S: METHOD:RESPONSE
            S: BEGIN:VEVENT
          
            S: DTSTART:19990310T090000Z
            S: DTEND:19990310T100000Z
            S: UID:abcxyz12345
            S: SUMMARY:Meet with  Sir Elton
            S: END:VEVENT
            S: BEGIN:VEVENT
            S: DTSTART:19990310T130000Z
            S: DTEND:19990310T133000Z
            S: UID:abcxyz8999
            S: SUMMARY:Meet with  brave brave Sir Robin
            S: END:VEVENT
            S: END:VCAP
            S: .
            S: 2.0 cap://bobo.ex.com/relcal3
            S: Content-type:text/calendar; Method=RESPONSE;
            S:    Component=VDATA; Optinfo=VERSION:2.1
          
          
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            S: Content-Transfer-Encoding: 7bit
            S:
            S: BEGIN:VCAP
            S: VERSION:2.1
            S: METHOD:RESPONSE
            S: BEGIN:VDATA
            S: BEGIN:VEVENT
            S: DTSTART:19990310T140000Z
            S: DTEND:19990310T150000Z
            S: UID:123456asdf
            S: SUMMARY:Summer Budget
            S: END:VEVENT
            S: END:VDATA
            S: END:VCAP
            S: .
          
          The return values are subject to VCAR filtering. That is, if
          the request contains properties to which the UPN does not have
          access, those properties will not appear in the return values.
          If the UPN has access to at least one property of events, but
          has been denied access to all properties called out in the
          request, the response will contain a single REQUEST-STATUS
          property indicating the error. That is, the VEVENT
          components will be the following:
          
            [EDITORS NOTE: Should the one(s) that the UPN has access to
          - be
            returned?]
            S: 2.0 cap://bobo.ex.com/sally
            S: Content-type:text/calendar;
          Method=RESPONSE;Component=VDATA;
            S:    Optinfo=VERSION:2.1
            S: Content-Transfer-Encoding: 7bit
            S:
            S: BEGIN:VCAP
            S: VERSION:2.1
            S: BEGIN:VDATA
            S: BEGIN:VEVENT
            S: REQUEST-STATUS:3.8
            S: END:VEVENT
          
          
            S: END:VDATA
            S: END:VCAP
            S: .
          
          If the UPN has no access to any events at all, the response
          will simply be an empty data set. The response looks the same
          
          
          
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          if there are particular events to which the requester has been
          denied access.
          
            S: 2.0 cap://bobo.ex.com/sally
            S: Content-type:text/calendar; Method=RESPONSE;
            S:  Component=VDATA;
            S: Optinfo=VERSION:2.1
            S: Content-Transfer-Encoding: 7bit
            S:
            S: BEGIN:VCAP
            S: VERSION:2.1
            S: BEGIN:VDATA
            S: END:VDATA
            S: END:VCAP
            S: .
          
          Find alarms within a range of time for booked (METHOD =
          CREATE) VEVENTs.
          
            C: SENDDATA
            C: Content-type:text/calendar; Method=READ; Component=VQUERY
            C:
            C: BEGIN:VCAP
            C: VERSION:2.1
            C: BEGIN:VCOMMAND
            C: METHOD:READ
            C: CMDID:xyz12345
            C: TARGET:relcal2
            C: TARGET:cap://bobo.ex.com/relcal3
            C: BEGIN:VQUERY
            C: QUERY:SELECT DTSTART,DTEND,SUMMARY,UID, VALARM.*
                FROM VEVENT,VTODO
                WHERE VALARM.TRIGGER >= '19990310T080000Z'
                AND VALARM.TRIGGER <= '19990310T190000Z'
                AND METHOD = 'CREATE'
            C: END:VQUERY
            C: END:VCOMMAND
            C: END:VCAP
            C: .
            S: 2.0 cap://bobo.ex.com/relcal3
            S: Content-type:text/calendar; Method=RESPONSE;
            S: Optinfo=VERSION:2.1
            S: Content-Transfer-Encoding: 7bit
            S:
            S: BEGIN:VCAP
            S: VERSION:2.1
            S: METHOD:RESPONSE
            S: CMDID:xyz12345
            S: TARGET:cap://bobo.ex.com/relcal3
          
          
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            S: BEGIN:VEVENT
            S: DTSTART:19990310T130000Z
            S: DTEND:19990310T133000Z
          
            S: UID:abcxyz8999
            S: SUMMARY:Meet with brave brave Sir Robin
            S: BEGIN:VALARM
            S: TRIGGER:19990310T132500Z
            S: SUMMARY:Almost time..
            S: ACTION:DISPLAY
            S: END:VALARM
            S: END:VEVENT
            S: END:VCAP
            S: .
            S: 2.0 cap://bobo.ex.com/relcal2
            S: Content-type:text/calendar; Method=RESPONSE;
            S: Optinfo=VERSION:2.1
            S: Content-Transfer-Encoding: 7bit
            S:
            S: BEGIN:VCAP
            S: VERSION:2.1
            S: METHOD:RESPONSE
            S: CMDID:xyz12345
            S: TARGET:cap://bobo.ex.com/relcal2
            S: BEGIN:VEVENT
            S: REQUEST-STATUS:2.0
            S: END:VEVENT
            S: END:VCAP
            S: .
          
          
          7.2.2  Scheduling Commands
          
          The following provide a set of scheduling commands (or
          methods) in CAP.  Scheduling commands allow a CU to indirectly
          manipulate a calendar by asking another CU to perform an
          operation on their calendar. For example, CU-A can request CU-
          B to add a meeting to their calendar; in effect inviting CU-B
          to the meeting.
          
          Calendar access rights can be granted for scheduling commands
          without granting rights for more generalized access with the
          calendar commands.
          
          [EDITORS NOTE: This section needs to be completed by adding
          the restriction tables for each of these iTIP methods. The
          basis for the text is to be taken from [iTIP].]
          
          
          
          
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          7.2.2.1   Reading Scheduling Components
          
          A CU might be invited to a meeting. If the CU had been invited
          by CAP, the entry in the CU calendar will be scheduled, but
          not booked. So a CUA will need to look for scheduled entries
          in the calendar and present them to the CU or automaticly
          decide if the invitation is to be accepted or processed.
          
          Example:
          
          The little league coach places the teams entire schedule into
          your calendar. Lets say that every game and practice is on a
          Friday night and your calendar now has this iTIP scheduling
          data:
          
            BEGIN:VCAP
            VERSION:2.0
            METHOD:PUBLISH
            BEGIN:VEVENT
            DTSTAMP;TZID=US/Pacific:20000229T180000
            DTSTART;TZID=US/Pacific:20000303T180000
            ORGANIZER:coach@little.league.com
            SUMMARY: Schedule of games and practice
            UID:1-coach@little.league.com
            SEQUENCE:0
            DESCRIPTION:Please have your child at the field
             and ready to play by 6pm.
            RRULE:FREQ=WEEKLY;COUNT=10
            END:VEVENT
            END:VCAP
          
          At this point the above VEVENT is not booked in your calendar,
          It is simply scheduled. A CUA would fetch this and all other
          scheduled VEVENTs from your calendar with:
          
            C: SENDDATA
            C: Content-type:text/calendar; Method=READ; Component=VQUERY
            C:
            C: BEGIN:VCAP
            C: VERSION:2.1
            C: BEGIN:VCOMMAND
            C: METHOD:READ
            C: CMDID:xyz12345
            C: TARGET:relcal2
            C: BEGIN:VQUERY
            C: QUERY:SELECT * WHERE FROM VEVENT METHOD != 'CREATE'
            C: END:VQUERY
            C: END:VCOMMAND
            C: END:VCAP
          
          
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            C: .
          
          The the CUA and CU could determine which scheduling items were
          to remain on the calendar. Each scheduling component could be
          deleted or updated with METHOD:MODIFY to change the METHOD
          from PUBLISH, REQUEST, REPLY, ADD, CANCEL, REFRESH, COUNTER,
          or DECLINE-COUNTER to what the CU and CUA had decided.
          
          In some cases the CUA could automaticly do the work and inform
          the CU. An example of this is CANCEL. If configured to process
          METHOD:CANCEL it could METHOD:DELETE the component an inform
          the CU that the booked component had been canceled.
          
          The CUA MUST process the scheduled components in the order
          sent. Some optimization could be done by the CUA. One example
          is if a PUBLISH and later a CANCEL for the same component with
          the same SEQUENCE number were scheduled, but not booked. The
          CUA might never inform the CU and treat it as if the PUBLISH
          had never been received by doing a METHOD:DELETE on both
          entries.
          
          It is important to note that scheduled components do not show
          up in busy time as BUSY. Only when they are booked does the
          TRANSP:OPAQUE property take effect. A CS implementation MAY
          mark the time as TENTATIVE. This is an implementation and
          administrative choice.
          
          
          7.2.2.2   PUBLISH
          
            Arguments:
          
            Data:      data as described below
          
            Result:    2.0 - success
                       2.2 - will attempt operation on the remote CAP
                             server
                       Permission
                       Calendar already exists
                       Bad args
                       Parent Calendar(s) not found
          
          This method is used to move a calendar within the CS's
          hierarchy of calendars. If the CU wishes to keep the published
          entry. A METHOD:MODIFY changing the entries METHOD from
          PUBLISH to CREATE would be done, booking the entry. Or
          METHOD:DELETE if the CU did not wish this scheduled item to
          exist in their calendar.
          
          
          
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          7.2.2.3   REQUEST
          
            Arguments:
          
            Data:      data as described below
          
            Result:    2.0 - success
                       2.2 - will attempt operation on the remote CAP
                             server
                       Permission
                       Calendar already exists
                       Bad args
                       Parent Calendar(s) not found
          
          This as described in [iTIP] and would be modified just like
          PUBLISH above.
          
          
          7.2.2.4   REPLY
          
            Arguments:
          
            Data:      data as described below
          
            Result:     2.0 - success
                        2.2 - will attempt operation on the remote CAP
                              server
                        Permission
                        Calendar already exists
                        Bad args
                        Parent Calendar(s) not found
          
          
          7.2.2.5   ADD
          
            Arguments:
          
            Data:      data as described below
          
            Result:    2.0 - success
                       2.2 - will attempt operation on the remote CAP
                             server
                       Permission
                       Calendar already exists
                       Bad args
                       Parent Calendar(s) not found
          
          
          
          
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          7.2.2.6   CANCEL
          
            Arguments:
          
            Data:      data as described below
          
            Result:    2.0 - success
                       2.2 - will attempt operation on the remote CAP
                             server
                       Permission
                       Calendar already exists
                       Bad args
                       Parent Calendar(s) not found
          
          
          7.2.2.7   REFRESH
          
            Arguments:
          
            Data:      data as described below
          
            Result:    2.0 - success
                       2.2 - will attempt operation on the remote CAP
                             server
                       Permission
                       Calendar already exists
                       Bad args
                       Parent Calendar(s) not found
          
          
          7.2.2.8   COUNTER
          
            Arguments:
          
            Data:      data as described below
          
            Result:    2.0 - success
                       2.2 - will attempt operation on the remote CAP
                             server
                       Permission
                       Calendar already exists
                       Bad args
                       Parent Calendar(s) not found
          
          
          7.2.2.9   DECLINECOUNTER
          
            Arguments:
          
          
          
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            Data:      data as described below
          
            Result:    2.0 - success
                       2.2 - will attempt operation on the remote CAP
                             server
                       Permission
                       Calendar already exists
                       Bad args
                       Parent Calendar(s) not found
          
          
          7.2.3  iTIP Examples
          
          The following examples describe scenarios for the handling of
          incoming iTIP data. An appropriate sort-order for the handling
          of incoming iTIP is by UID, Recurrence-id, sequence, dtstamp.
          This processing may be optimized, for instance, REFRESHs could
          be processed last.
          
          As an update to [iTIP], data with the "COUNTER" method should
          be processed even if the Sequence number is stale.
          
          
          7.2.3.1   Sending and Receiving an iTIP request
          
          In this example A invites B and C to a meeting, B accepts the
          meeting and C rejects it. The calendars for A, B and C are
          relcal1, relcal2 and relcal3 respectively, and are all on the
          same server, "cal.foo.com". A lot of these described actions
          are performed by the CUAs and not the users themselves, the
          CUAs are called A-c, B-c and C-c respectively.
          
          A wishes to create a meeting with B and C, so A-c uses CAP to
          send the following iTIP request to relcal2 and relcal3, while
          logged in to "cal.foo.com".
          
            BEGIN:VCAP
            VERSION:2.1
          
            CMDID:xhj-dd
            BEGIN:VCOMMAND
            METHOD:REQUEST
            TARGET:cap://cal.foo.com/relcal2
            TARGET:relcal3
            BEGIN:VEVENT
            UID:abcd12345
            DTSTART:19990307T180000Z
            DTEND:19990307T190000Z
            ORGANIZER:cap://cal.foo.com/relcal1
          
          
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            ATTENDEE;RSVP=TRUE;PARTSTAT=NEEDS-
          ACTION:cap://cal.foo.com/relcal2
            ATTENDEE;RSVP=TRUE;PARTSTAT=NEEDS-
          ACTION:cap://cal.foo.com/relcal3
            SUMMARY:Important Meeting
            END:VEVENT
            END:VCOMMAND
            END:VCAP
          
          An incoming event (indicated by the value of the "METHOD"
          property) then appears in relcal2 and relcal3, with the
          following data:
          
            BEGIN:VEVENT
            METHOD:REQUEST
            UID:abcd12345
            DTSTART:19990307T180000Z
            DTEND:19990307T190000Z
            ORGANIZER:cap://cal.foo.com/relcal1
            ATTENDEE;RSVP=TRUE;PARTSTAT=NEEDS-ACTION:cap://cal.foo.c
             om/relcal2
            ATTENDEE;RSVP=TRUE;PARTSTAT=NEEDS-ACTION:cap://cal.foo.c
             om/relcal3
            SUMMARY:Important Meeting
            END:VEVENT
          
          B-c and C-c must search for such incoming events, they do so
          using the following CAP search:
          
            BEGIN:VCAP
            VERSION:2.1
            BEGIN:VCOMMAND
            METHOD:READ
            CMDID:xhr-de
            TARGET:relcal2
            # or TARGET:relcal3
            BEGIN:VCOMMAND
            BEGIN:VQUERY
            QUERY:SELECT * FROM VEVENT WHERE METHOD = 'REQUEST';
            END:VQUERY
            END:VCOMMAND
            END:VCOMMAND
            END:VCAP
          
          In response to this search they get the above event. B-c and
          C-c must then crack open the VEVENT, find the UID and
          determine if there is already an event on their calendar with
          that UID. To do this they use the following search:
          
          
          
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            BEGIN:VCAP
            VERSION:2.1
            BEGIN:VCOMMAND
            METHOD:READ
            CMDID:xhr-df
            TARGET:relcal2
          
            BEGIN:VCOMMAND
            BEGIN:VQUERY
            QUERY:SELECT * FROM VEVENT WHERE UID = 'abcd12345' AND
             METHOD = 'CREATE'
            END:VQUERY
            END:VCOMMAND
            END:VCOMMAND
            END:VCAP
          
          We assume that the event is not already in their relcal2 or
          relcal3.
          
          B-c prompts B who decides to accept the meeting request, and
          B-c creates a copy of the event in relcal2, with the
          "PARTSTAT" parameter set to ACCEPTED. B-c also sends this copy
          to the Organizer at relcal1 as an iTIP REPLY, preserving the
          CMDID:
          
            BEGIN:VCAP
            VERSION:2.1
            CMDID:xhj-dd
            METHOD:REPLY
            TARGET:cap://cal.foo.com/relcal1
            BEGIN:VEVENT
            UID:abcd12345
            DTSTART:19990307T180000Z
            DTEND:19990307T190000Z
            ORGANIZER:cap://cal.foo.com/relcal1
            ATTENDEE;PARTSTAT=ACCEPTED:cap://cal.foo.com/relcal2
            SUMMARY:Important Meeting
            END:VEVENT
            END:VCAP
          
          C, on the other hand, decides to decline the meeting, and C-c
          sends a reply to the Organizer to that effect, as follows:
          
            BEGIN:VCALENDAR
            VERSION:2.1
            CMDID:xhj-dd
            METHOD:REPLY
            TARGET:cap://cal.foo.com/relcal1
            BEGIN:VEVENT
          
          
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            UID:abcd12345
            DTSTART:19990307T180000Z
            DTEND:19990307T190000Z
            ORGANIZER:cap://cal.foo.com/relcal1
            ATTENDEE;PARTSTAT=DECLINED:cap://cal.foo.com/relcal3
            SUMMARY:Important Meeting
            END:VEVENT
            END:VCALENDAR
          
          It is preferable that C-c store the event in relcal3 even
          though it has been declined. Storing the event in relcal3
          allows subsequent iTIP messages to be interpreted correctly.
          The "PARTSTAT" parameter indicates that the event was refused.
          
          After receiving the replies from relcal2 and relcal3, A-c
          updates the version of the event in relcal1 to indicate the
          new participation status:
          
            BEGIN:VEVENT
            METHOD:REQUEST
            UID:abcd12345
            DTSTART:19990307T180000Z
            DTEND:19990307T190000Z
            ORGANIZER:cap://cal.foo.com/relcal1
            ATTENDEE;PARTSTAT=ACCEPTED:cap://cal.foo.com/relcal2
            ATTENDEE;PARTSTAT=DECLINED:cap://cal.foo.com/relcal3
            SUMMARY:Important Meeting
            END:VEVENT
          
          A-c then sends a new iTIP request to relcal2 only, indicating
          the updated information.
          
          
          7.2.3.2   Handling an iTIP refresh
          
          A little bit later, C is thinking about accepting the event in
          the previous example, but first wants to check the current
          state of the event. To find the current state C-c uses the
          iTIP "REFRESH" method, sending the following to relcal1:
          
            BEGIN:VCALENDAR
            VERSION:2.1
            CMDID:xud-pn
            METHOD:REFRESH
            TARGET:cap://cal.foo.com/relcal1
            BEGIN:VEVENT
            UID:abcd12345
            ORGANIZER:cap://cal.foo.com/relcal1
            ATTENDEE:cap://cal.foo.com/relcal3
          
          
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            DTSTAMP:19990306T202333Z
            END:VEVENT
            END:VCALENDAR
          
          A-c finds the refresh as an incoming iTIP, and searches for
          the corresponding event. Having found the event (with no
          changes since the last example) A-c then verifies that relcal3
          is in fact an Attendee of the event and is thus allowed to
          request a refresh. (In the case of a published event things
          are more complicated.) A-c packages the event up as an iTIP
          request and sends it to relcal3:
          
            BEGIN:VCALENDAR
            VERSION:2.1
            CMDID: xud-pn
            METHOD:REQUEST
            TARGET:cap://cal.foo.com/relcal3
            BEGIN:VEVENT
            UID:abcd12345
            DTSTART:19990307T180000Z
            DTEND:19990307T190000Z
            ORGANIZER:cap://cal.foo.com/relcal1
            ATTENDEE;PARTSTAT=ACCEPTED:cap://cal.foo.com/relcal2
          
          
            ATTENDEE;PARTSTAT=DECLINED:cap://cal.foo.com/relcal3
            SUMMARY:Important Meeting
            SEQUENCE:0
            DTSTAMP:19990306T204333Z
            END:VEVENT
            END:VCALENDAR
          
          
          7.2.3.3   Sending and accepting an iTIP counter
          
          Having received the latest copy of the event C wishes to
          propose a venue for the event, using an iTIP COUNTER. To do
          this C-c sends the following to relcal1:
          
            BEGIN:VCAP
            VERSION:2.1
            CMDID:zzykjjk
            METHOD:COUNTER
            TARGET:cap://cal.foo.com/relcal1
            BEGIN:VEVENT
            UID:abcd12345
            DTSTART:19990307T180000Z
            DTEND:19990307T190000Z
            ORGANIZER:cap://cal.foo.com/relcal1
          
          
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            ATTENDEE;PARTSTAT=DECLINED:cap://cal.foo.com/relcal3
            SUMMARY:Important Meeting
            LOCATION:La Belle Province
            COMMENT:My favorite restaurant, I'll definitely go if it's
          there.
            END:VEVENT
            END:VCAP
          
          Having sent the information to relcal1, C-c shouldn't store
          the new details in relcal3. If C-c updated the version in
          relcal3 and relcal1 did not reply to the counter, then relcal3
          would have incorrect information. Instead C-c preserves the
          correct information and waits for a response from relcal1. A
          CUA implementation may wish to preserve this information
          itself, externally to the CS.
          
          In order to receive an iTIP counter A-c follows the same
          search as for other iTIP data, first find the incoming
          message, next find any matching events in the calendar store.
          
          Having found the matching event, A reviews the proposed
          changes and decides to accept the COUNTER. To do this, A-c
          modifies the version in relcal1 (bumping the sequence number)
          to:
          
            BEGIN:VEVENT
            METHOD:CREATE
            UID:abcd12345
            DTSTART:19990307T180000Z
            DTEND:19990307T190000Z
            ORGANIZER:cap://cal.foo.com/relcal1
            ATTENDEE;PARTSTAT=ACCEPTED:cap://cal.foo.com/relcal2
          
            ATTENDEE;PARTSTAT=DECLINED:cap://cal.foo.com/relcal3
            SUMMARY:Important Meeting
            LOCATION:La Belle Province
            SEQUENCE:1
            END:VEVENT
          
          A-c then sends the updated version as a request to both
          relcal2 and relcal3:
          
            BEGIN:VCAP
            VERSION:2.1
            CMDID:xup-po
            METHOD:REQUEST
            TARGET:cap://cal.foo.com/relcal2
            TARGET:cap://cal.foo.com/relcal3
            BEGIN:VEVENT
          
          
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            UID:abcd12345
            DTSTART:19990307T180000Z
            DTEND:19990307T190000Z
            ORGANIZER:cap://cal.foo.com/relcal1
            ATTENDEE;RSVP=TRUE;PARTSTAT=NEEDS-
          ACTION:cap://cal.foo.com/relcal2
            ATTENDEE;RSVP=TRUE;PARTSTAT=NEEDS-
          ACTION:cap://cal.foo.com/relcal3
            SUMMARY:Important Meeting
            LOCATION:La Belle Province
            SEQUENCE:1
            DTSTAMP:19990307T054339Z
            END:VEVENT
            END:VCAP
          
          
          7.2.3.4   Declining an iTIP counter
          
          B does not like the new location and also counters the event,
          B-c sends the following iTIP:
          
            BEGIN:VCAP
            VERSION:2.1
            CMDID:xim-ef
            METHOD:COUNTER
            TARGET:cap://cal.foo.com/relcal1
            BEGIN:VEVENT
            UID:abcd12345
            DTSTART:19990307T180000Z
            DTEND:19990307T190000Z
            ORGANIZER:cap://cal.foo.com/relcal1
            ATTENDEE:cap://cal.foo.com/relcal2
            SUMMARY:Important Meeting
            LOCATION:Au Coin Dor=E9
            END:VEVENT
            END:VCAP
          
          However, C does not accept the counter, and C-c replies with a
          decline counter:
          
            BEGIN:VCAP
            VERSION:2.1
            CMDID:xim-ef
            METHOD:DECLINE-COUNTER
            TARGET:cap://cal.foo.com/relcal2
            BEGIN:VEVENT
            DTSTAMP:19990307T093245Z
            UID:abcd12345
            ORGANIZER:cap://cal.foo.com/relcal1
          
          
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            SEQUENCE:1
            END:VEVENT
            END:VCAP
          
          Fortunately B-c kept the original information when sending the
          counter, and there is no problem when no information is
          returned in the DECLINE-COUNTER.
          
          
          8  Response Codes
          Numeric response codes are returned at both the transfer and
          application layer. The same set of codes is used in both
          cases.
          
          [EDITORS NOTE: Do we want to use the same set of codes?]
          
          The format of these codes is described in [iCAL], and extend
          in [iTIP] and [iMIP]. The following describes new codes added
          to this set.
          
          At the application layer response codes are returned as the
          value of a "REQUEST-STATUS" property. The value type of this
          property is modified from that defined in [iCAL], to make the
          accompanying text optional.
          
          
          Code  Params      Description
          --------------------------------------------------------------
          2.0  [CMDID] varies
                            Success, The parameters vary with the
                            operation and are specified.
          
          2.0.1  [CMDID]    Success, send data, terminate  with
                            <CRLF>.<CRLF>
          
          2.0.2  [CMDID]    A reply is pending. It could not be com-
                            pleted in the specified amount of time.
                            The server awaits a CONTINUE or ABORT
                            command. If can optionally be followed
                            by a CMDID. If the SENDDATA object con-
                            tained a CMDID, then the CS MUST append
                            the CMDID to the 2.0.2 reply for that
                            object.
          
          2.0.3  [CMDID]    In response to the client issuing an
                            ABORT command, this reply code indicates
                            that any command currently underway was
                            successfully aborted. If can optionally
                            be followed by a CMDID. If the SENDDATA
          
          
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                            object contained a CMDID, then the CS
                            MUST append the CMDID to the 2.0.2 reply
                            for that object.
          
          2.0.6  [CMDID]    An operation is being attempted on a
                            re-mote server. This response indicates
                            that the server has not yet been con-
                            tacted but an attempt will be made to
                            contact it after the command has been
                            sent.
          
          3.1.4  [CMDID]    Capability not supported.
          
          4.1   [CMDID]     Calendar store access denied.
          
          6. 1  [CMDID]     Authenticate failure: unsupported au-
                            thentication mechanism, credentials re-
                            jected.
          
          6.2   [CMDID]     Sender aborted authentication, authenti-
                            cation exchange cancelled.
          
          6.3   [CMDID]     Attempt to create or modify an event
                            such that it would overlap another event
                            in either of the following two circum-
                            stances:
          
                            (a) One of the events has a TRANSP
                            property set to OPAQUE-NOCONFLICT or
                            TRANSPARENT-NOCONFLICT.
          
                            (b) The calendar's ALLOW-CONFLICT
                            property is set to NO.
          
          6.XXX  [CMDID]    [EDITORS NOTE: More are in this memo -
                            add here TODO]
          
          7.0  [CMDID]      A timeout has occurred. The server was
                            unable to complete the operation in the
                            requested time.
          
          8.0  [CMDID]      A failure has occurred in the Receiver
                            that prevents the operation from
                            succeeding.
          
          8.1  [CMDID]      Sent when a session cannot be
                            established because the CAP Server is too
                            busy.
          
          
          
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          8.2  [CMDID]      Used to signal that an ICAL object has
                            exceeded the server's size limit
          
          8.3  [CMDID]      A DATETIME value was too large to be
                            represented on this Calendar.
          
          8.4  [CMDID]      A DATETIME value was too far in the past
                            to be represented on this Calendar.
          
          8.5  [CMDID]      An attempt was made to create a new
                            object but the unique id specified is
                            already in use.
          
          9.0  [CMDID]      An unrecognized command was received.
          
          10.1  <old-address> <new- address> [CMDID]
                            Accompanied by an alternate address. The
                            RECIPIENT specified should be contacted at
                            the given alternate address. The
                            referral address MUST follow the reply
                            code.
          
          10.2              The server is shutting down.
          
          10.4              The operation has not be performed
                            because it would cause the resources
                            (memory, disk,CPU, etc) to exceed the
                            allocated quota.
          
          10.5  [CMDID]     The ITIP message has been queued too too
                            long. Delivery has been aborted.
          --------------------------------------------------------------
          
          9  Examples
          
          For all the examples in this section, the authenticated user
          is  user@example.com.
          
          9.1 Authentication Examples
          
          
          9.1.1  Login Using Kerberos V4
          
            Use Kerberos V4 to authenticate as bill@example.com to the
          CAP server on
            cal.example.com.
          
            C: <connect to cal.example.com on port ...>
            S: 2.0
          
          
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            S: .
            C: CAPABILTY
            S: CAPVERSION=1.0
            S: ITIPVERSION=1.0
            S: AUTH=KERBEROS_V4
            S: AUTH=DIGEST_MD5
            S: .
            C: AUTHENTICATE KERBEROS_V4
            S: AmFYig==
            C: BAcAQU5EUkVXLkNNVS5FRFUAOCAsho84kLN3/IJmrMG+25a4DT
            S: or//EoAADZI=
            C: DiAF5A4gA+oOIALuBkAAmw==
            S: 2.0
            S: IDENTITY=bill@example.com
            S: CAPVERSION=1.0
          
            S: ITIPVERSION=1.0
            S: AUTH=KERBEROS_V4
            S: AUTH=DIGEST_MD5
            S: CAR=CAR-FULL-1
            S: MINDATE=19700101T000000Z
            S: MAXDATE=20380118T191407Z
            S: .
          
          
          9.1.2  Error Scenarios
          
          Use of SASL Authorization Identity is not supported. Use the
          IDENTITY command instead. If you attempt to use the
          Authorization Identity, an error status will be returned.
          
            C: AUTHENTICATE KERBEROS_V4
            S: AmFYig==
            C: BAcAQU5EUkVXLkNNVS5FRFUAOCAsho84kLN3/IJmrMG+25a4DT
            S: or//EoAADZI=
            C: DiAF5A4gA+oOIALuBkAAmw==
            S: 6.1
            S: .
          
          Sender aborted authentication:
          
            C: AUTHENTICATE KERBEROS_V4
            S: AmFYig==
            C: .
            S: 6.2
            S: .
          
          Unsupported mechanism:
          
          
          
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            C: AUTHENTICATE Experimental_Auth
            S: 6.3
            S: .
          
          
          9.2 Read Examples
          
          
          10.2.1. Read From A Single Calendar
          
          In this example bill@example.com reads a day's worth of events
          from cap://cal.example.com/opaqueid99.
          
            C: SENDDATA
            C: Content-type:text/calendar; Method=READ; Component=VQUERY
            C:
            C: BEGIN:VCAP
            C: VERSION:2.1
            C: BEGIN:VCOMMAND
            C: METHOD:READ
            C: CMDID:xyz12345
          
          
            C: TARGET:cap://cal.example.com/opaqueid99
            C: BEGIN:VQUERY
            C: QUERY:SELECT DTSTART,DTEND,SUMMARY, UID FROM VEVENT
              WHERE DTEND >= '19990714T080000Z'
              AND DTSTART <= '19990715T080000Z'
            C: END:VQUERY
            C: END:VCOMMAND
            C: END:VCAP
            C: .
            # this response code means that the transport successfully
            # delivered the data.
            S: 2.0 ; got the request OK ; really
            S: .
            S: Content-type:text/calendar; Method=RESPONSE;
            S:  Optinfo=VERSION:2.1
            S: Content-Transfer-Encoding: 7bit
            S:
            S: BEGIN:VCAP
            S: VERSION:2.1
            S: METHOD:RESPONSE
            S: TARGET:cap://cal.example.com/opaqueid99
            S: CMDID:xyz12345
            S: REQUEST-STATUS:2.0
            S: BEGIN:VEVENT
            S: DTSTART:19990714T200000Z
            S: DTEND:19990714T210000Z
          
          
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            S: UID:000444888929922
            S: SUMMARY:Blah bla
            S: END:VEVENT
            S: BEGIN:VEVENT
            S: UID:0034848098038888989443
            S: SUMMARY:meeting
            S: DTEND:19990714T233000Z
            S: DTSTART:19990714T223000Z
            S: END:VEVENT
            S: END:VCAP
            S: .
          
          
          9.2.1  Read From Multiple Calendars
          
          In this example bill@example.com reads a day's worth of events
          from cap://cal.example.com/opaqueid101 and
          cap://cal.example.com/opaqueid103
          
            C: SENDDATA
            C: Content-type:text/calendar; Method=READ; Component=VQUERY
            C:
            C: BEGIN:VCAP
            C: VERSION:2.1
            C: BEGIN:VCOMMAND
            C: METHOD:READ
            C: CMDID:xyz12346
            C: TARGET:cap://cal.example.com/opaqueid101
            C: TARGET:opaqueid103
            C: BEGIN:VQUERY
            C: VSCOPE:VEVENT
          
          
            C: QUERY:SELECT DTSTART,DTEND,SUMMARY,UID FROM VEVENT
            C: WHERE DTEND >= 19990714T080000Z AND
            C:   DTSTART <= 19990715T080000Z
            C: END:VQUERY
            C: END:VCOMMAND
            C: END:VCAP
            C: .
            S: 2.0
            S: .
            S: Content-Type:multipart/mixed;
            S:  boundary="--FEE3790DC7E35189CA67"
            S:
            S: ----FEE3790DC7E35189CA67
            S: Content-type:text/calendar; Method=RESPONSE;
            S: Optinfo=VERSION:2.1
            S: Content-Transfer-Encoding: 7bit
          
          
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            S:
            S: BEGIN:VCAP
            S: VERSION:2.1
            S: METHOD:RESPONSE
            S: TARGET:cap://cal.example.com/opaqueid103
            S: CMDID:xyz12346
            S: REQUEST-STATUS:2.0
            S: BEGIN:VEVENT
            S: UID:0034848098038888989443
            S: SUMMARY:meeting
            S: DTEND:19990714T233000Z
            S: DTSTART:19990714T223000Z
            S: END:VEVENT
            S: END:VCAP
            S:
            S: ----FEE3790DC7E35189CA67CE2C
            S: Content-type:text/calendar; Method=RESPONSE;
            S: Optinfo=VERSION:2.1
            S: Content-Transfer-Encoding: 7bit
            S:
            S: BEGIN:VCAP
            S: VERSION:2.1
            S: METHOD:RESPONSE
            S: TARGET:cap://cal.example.com/opaqueid101
            S: CMDID:xyz12346
            S: REQUEST-STATUS:4.1 ; access denied
            S: END:VCAP
            S:
            S: ----FEE3790DC7E35189CA67CE2C
            S: .
          
          
          9.2.2  Timeouts
          
          In this example bill@example.com attempts to read a calendar
          but the latency time he supplies is not sufficient for the
          server to complete the command.
          
            C: SENDDATA 3
            C: Content-type:text/calendar; Method=READ; Component=VQUERY
          
          
            C:
            C: BEGIN:VCAP
            C: VERSION:2.1
            C: BEGIN:VCOMMAND
            C: METHOD:READ
            C: CMDID:xyz12346
            C: TARGET:cap://cal.example.com/opaqueid101
          
          
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            C: TARGET:opaqueid103
            C: BEGIN:VQUERY
            C: QUERY:SELECT DTSTART,DTEND,SUMMARY,UID FROM VEVENT
            C:   WHERE DTEND >= '19990714T080000Z' AND
            C:   DTSTART <= '19990715T080000Z'
            C: END:VQUERY
            C: END:VCOMMAND
            C: END:VCALENDAR
            C: .
            S: 7.0 ; xyz12346
            S: .
            S: .
          
          If Bill wants to continue and give the server more time he
          would issue a CONTINUE command:
          
            C: CONTINUE 10 ; xyz12346
          
          If Bill wants to abort the command and not wait any further he
          would issue an ABORT command:
          
            C: ABORT ; xyz12346
            S: 2.0
            S: .
            S: .
          
          
          9.2.3  Using Parent and Children Properties
          
          
          9.2.4  Query VEVENT.DTSTART and VALARM.DTSTART
          
          
          10 Implementation Issues
          
          1. What are the minimum component properties set required to
          create a new VEVENT, VTODO and VJOURNAL?. PROPOSAL: DTSTART,
          SUMMARY and UID.
          
          [EDITORS NOTE (dr): They MUST be the same as for iTIP]
          
          2. What is the state of all undefined properties? PROPOSAL:
          Not defined. So a query will not return them, if they are
          selected.
          
          [EDITORS NOTE (dr): Many have default values, a CS may return
          the default values?]
          
          
          
          
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          11 Properties
          
          [EDITORS NOTE: These extensions/changes to iCalendar need to
          be reformatted to conform to the IANA registration process
          defined in section 7 of [iCAL].]
          
          
          11.1    Calendar Store Properties
          The following are properties of the calendar store.
          
          Name           Read  Value     Description
                         Only  Type
          --------------------------------------------------------------
          CALMASTER      N     URI       The email address for a
                                         Responsible person. MUST be a
                                         mailto URL.
          
          CSID           Y     URI       The CSID of this calendar
                                         store. If not specified, it is
                                         the same as the hostname or
                                         virtual host name.
          
          DEFAULT_VCARS  N     TEXT      A multivalued property
                                         Containing the default VCARs
                                         for newly created top level
                                         calendars. Each entry is a
                                         CARID It MUST include at a
                                         minimum
                                         READBUSYTIMEINFO,REQUESTONLY,
                                         UPDATEPARTSTATUS, and
                                         DEFAULTOWNER.
          
          MAXDATE        Y     DATE-TIME The date/time in the future
                                         beyond which the server cannot
                                         represent. If not specified,
                                         then 99991231T235959 will be
                                         assumed.
          
          MINDATE        Y     DATE-TIME The date/time in the past prior
                                         To which the server cannot
                                         represent. If not specified,
                                         then 00000101T000000 will be
                                         assumed.
          
          CURRENT_DATETIME  Y  DATE-TIME Current server time. This is
                                         returned as a local time and
                                         TZID.
          
          RECUR_ACCEPTED  Y    BOOLEAN   Boolean value will be set to
          
          
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                                         TRUE if the server will accept
                                         recurrence rules. It will be
                                         set to FALSE if the server will
                                         not accept recurrence rules. If
                                         not specified a CUA MUST assume
                                         TRUE.
          
          RECUR_EXPAND   Y     BOOLEAN   If set to TRUE, the CS supports
                                         The expansion of recurrence
                                         rules. If set to FALSE, the CS
                                         is incapable of expanding
                                         recurrence rules. If not
                                         specified a CUA MUST assume
                                         TRUE.
          
          RECUR_LIMIT    Y   INTEGER     This numeric value describes
                                         How the server handles
                                         unbounded recurrences. The
                                         value is only valid if
                                         RECURRENCE is TRUE. If the
                                         value is 0 it means that the
                                         server supports unbounded
                                         recurrence rules. If it is non-
                                         zero, it is a positive integer
                                         indicating the number of
                                         instances that will be created
                                         when the server expands an
                                         unbounded recurrence rule when
                                         fetched from the CS. A CUA MUST
                                         query for date ranges when this
                                         value is zero.
          
          VERSION        Y   TEXT        The version of the CS. The
                                         Default and the only currently
                                         Supported version is "2.0" to
                                         match the [iCAL] VERSION.
          
          
          11.2    Calendar Properties
          
          Name           Read  Value     Description
                         Only  Type
          --------------------------------------------------------------
          ALLOW-CONFLICTS N    BOOLEAN   This boolean value indicates
                                         Whether or not the calendar
                                         supports event conflicts. That
                                         is, whether or not any of the
                                         events in the calendar can
                                         overlap. If not specified the
          
          
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                                         default value is TRUE meaning
                                         that conflicts are allowed.
          
          CALSCALE        N    TEXT      The CALSCALE for this calendar.
                                         If not specified the default is
                                         GREGORIAN.
          
          CHARSET         N    TEXT      The default charset for
                                         Localized strings in this
                                         calendar. If not specified, the
                                         default is UTF-8.
          
          CHILDREN        Y    TEXT      The list of sub-calendars
                                         Belonging to this calendar. An
                                         empty list means no children.
                                         The results may be a comma
                                         separated list of children.
                                         Each entry returned is a CALID.
                                         The default is an empty list.
          
          CREATED         Y    DATE-TIME The timestamp of the calendar's
                                         create date.
          
          DEFAULT_VCAR    N    TEXT      The default VCARs for newly
                                         Created top level calendars.
                                         This is a CARID. The default
                                         value is the value of
                                         DEFAULT_VCAR in the CALSTORE
                                         table.
          
          LANGUAGE        N    TEXT      The default language for
                                         localizable strings in this
                                         calendar. There is no default.
                                         This value MUST NOT be empty.
          
          LAST-MODIFIED   N    DATE-TIME The timestamp when the
                                         Properties of the calendar were
                                         last updated. Default is the
                                         same as CREATED.
          
          NAME            N    TEXT      The display name for this
                                         calendar. It is a localizable
                                         string. If not provided, an
                                         empty value will be returned.
          
          OWNERS          N    URI       A multi-instanced property
                                         indicating the calendar owner.
                                         Each entry returned will be a
                                         UPN. There must be at least one
          
          
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                                         owner.
          
          PARENT          N    URI       The CALID of this calendars
                                         Parent maintained by a CAP
                                         server. An empty value means
                                         the calendar is the top level
                                         parent. The default value is no
                                         parent.
          
          RELCALID        N    URI       A unique name for the calendar.
                                         There is no default value and
                                         This value MUST NOT be empty.
          
          TOMBSTONE       N    BOOLEAN   TRUE indicator that this
                                         Calendar has been marked as
                                         deleted. The default value is
                                         FALSE.
          
          TZID            N    TEXT      The id of the timezone
                                         Associated with this calendar.
                                         See TZID in [iCAL]. The default
                                         value is GMT.
          
          12 Security Considerations
          
          For the mandatory SASL mechanism that CAP specifies, the
          mechanism support is:
          
            MUST authentication
            MUST authorization
            MAY impersonation
          
          
          13 CAP Item Registration
          
          This section provides the process for registration of new or
          modified CAP entities.
          
          13.1    Registration of New and Modified CAP Entities
          New CAP entities are registered by the publication of an IETF
          Request for Comment (RFC). Changes to a CAP item are
          registered by the publication of a revision of the RFC
          defining the method.
          
          13.2    Registration of New Entities
          
          This section defines procedures by which new entities (i.e.,
          components, properties, parameters, enumerated values or
          
          
          
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          restriction tables) for a CAP item can be registered with the
          IANA.
          
          Non-standard, experimental entities can be used by bilateral
          agreement, provided the associated properties names follow the
          "X-" convention. Such non-standard and experimental entities
          are non-IANA entities and need not be registered using this
          process.
          
          The procedures defined here are designed to allow public
          comment and review of new CAP entities, while posing only a
          small impediment to the definition of new properties.
          
          Registration of a new CAP item is accomplished by the
          following steps.
          
          
          13.2.1  Define the Item
          A CAP item is defined by completing the following template.
          
            To: ietf-calendar@imc.org
            Subject: Registration of CAP item XXX
            Item name:
            Item purpose:
            Description:
            CAP terminology changes:
            CAP data model changes:
            CAP system model changes:
            Conformance considerations:
            Format definition:
            Examples:
          
          The meaning of each field in the template is as follows.
          
          Item name: The name of the item.
          
          Item purpose: The purpose of the item (e.g., Extends the CAP
          command set to poll for notifications, etc.). Give a short but
          clear description.
          
          Description: Any special notes about the item, how it is to be
          used, etc.
          
          CAP terminology changes: Any change or additions to the
          existing CAP terminology needs to be specified.
          
          CAP data model changes: Any of the valid property parameters
          for the property needs to be specified.
          
          
          
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          CAP system model changes:
          
          Conformance: A clear summary of how and where this CAP item
          extension MUST, MAY, SHOULD or can be used. Any changes or
          impact to the existing conformance definition for CAP should
          be explained. The impact to implementations conforming to the
          existing CAP specification should be clearly described.
          
          Format definition: The ABNF for each element of the CAP item
          needs to be specified.
          
          Examples: One or more examples of instances of the CAP item
          and each of its usage scenarios needs to be specified.
          
          13.2.2  Post the item definition
          
          The item description MUST be posted to the new item discussion
          list, ietf-calendar@imc.org.
          
          13.2.3  Allow a comment period
          
          Discussion on the new item MUST be allowed to take place on
          the list for a minimum of two weeks. Consensus MUST be reached
          on the property before proceeding to the next step.
          
          13.2.4  Submit the proposal for approval
          
          Once the two-week comment period has elapsed, and the proposer
          is convinced consensus has been reached on the proposal, the
          registration application should be submitted to the Method
          Reviewer for approval. The Method Reviewer is appointed by the
          Application Area Directors and can either accept or reject the
          proposal registration. An accepted registration should be
          passed on by the Method Reviewer to the IANA for inclusion in
          the official IANA method registry. The registration can be
          rejected for any of the following reasons. 1) Insufficient
          comment period; 2) Consensus not reached; 3) Technical
          deficiencies raised on the list or elsewhere have not been
          addressed. The Method Reviewers decision to reject a proposal
          can be appealed by the proposer to the IESG, or the objections
          raised can be addressed by the proposer and the proposal
          resubmitted.
          
          [EDITORS NOTE: John Stracke to review any updates]
          
          
          13.3    Property Change Control
          
          
          
          
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          Existing CAP entities can be changed using the same process by
          which they were registered.
          
            1. Define the change
            2. Post the change
            3. Allow a comment period
            4. Submit the proposal for approval
          
          Note that the original author or any other interested party
          can propose a change to an existing CAP object, but that such
          changes should only be proposed when there are serious
          omissions or errors in the published memo. The Method Reviewer
          can object to a change if it is not backward compatible, but
          is not required to do so.
          
          CAP objects definitions can never be deleted from the IANA
          registry, but objects which are no longer believed to be
          useful can be declared OBSOLETE by adding this text to their
          "Item purpose" field.
          
          
          14 IANA Considerations
          
          This memo defines IANA registered extensions to the attributes
          defined by iCalendar, as defined in [iCAL], and [iTIP], as
          defined in [VCARD].
          
          [EDITORS NOTE (DR): RFC2426 - is vCard. This needs more
          explanation. What does vCARD have todo with this?]
          
          IANA registration proposals for iCalendar and iTIP are to be
          mailed to the registration agent for the "text/calendar"
          [MIME] content-type, <MAILTO: ietf-calendar@imc.org> using the
          format defined in section 7 of [iCAL].
          
          
          15 Acknowledgments
          
          The following have individuals were major contributors in the
          drafting and discussion of this memo:
          
          Harald Alvestrand, Mario Bonin, Andre Courtemanche, Dave
          Crocker, Pat Egen, Gilles Fortin, Jeff Hodges, Alex Hoppman,
          Bruce Kahn, Lisa Lippert, David Madeo, Bob Mahoney, Bob
          Morgan, Pete O'Leary, Richard Shusterman, Tony Small, John
          Stracke, Mark Wahl, Alexander Taler.
          
          
          
          
          
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          16 Bibliography
          
          [MIME] N. Borenstein and N. Freed, "MIME (Multipurpose
          Internet Mail Extensions) Part One: Mechanisms for Internet
          Draft UTF-825 July 1996
          
          Specifying and Describing the Format of Internet Message
          Bodies", RFC 1521, Bellcore, Innosoft, September 1993.
          
          [TLS] Dierks, Allen, "The TLS Protocol", RFC 2246, January
          1999
          
          
          [RFC2119] TODO...
          
          [SASL] RFC2222 TODO...
          
          [URL] Berners-Lee, Fielding, Masinter, "Uniform Resource
          Identifiers
          
          (URI): Generic Syntax", RFC 2396, August 1998.
          
          [iCAL] Dawson, Stenerson, "Internet Calendaring and Scheduling
          Core Object Specification (iCalendar)", RFC 2445, November
          1998
          
          [iTIP] Silverberg, Mansour, Dawson, Hopson, "iCalendar
          Transport-Independent Interoperability Protocol (iTIP)", RFC
          2446, November 1998
          
          [iMIP] Dawson, Mansour, Silverberg, "iCalendar Message-Based
          Interoperability Protocol (iMIP)", RFC 2445, November 1998
          
          [SQL] "Database Language SQL", ANSI/ISO/IEC 9075: 1992, aka
          ANSI X3.135-1992, aka FiPS PUB 127-2
          
          [SQLCOM] ANSI/ISO/IEC 9075:1992/TC-1-1995, Technical
          corrigendum 1 to ISO/IEC 9075: 1992, also adopted as Amendment
          1 to ANSI X3.135.1992
          
          [UNICODE] The Unicode Consortium, "The Unicode Standard -
                                                                  -
          Worldwide Character Encoding -- Version 1.0", Addison-Wesley,
          Volume 1, 1991, Volume 2, 1992. UTF-8 is described in Unicode
          Technical Report #4.
          
          [US-ASCII] Coded Character Set--7-bit American Standard Code
          for Information Interchange, ANSI X3.4-1986.
          
          [VCARD] RFC.... TODO
          
          
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          17 Author's Address
          The following address information is provided in a vCard v3.0,
          the [VCARD] electronic business card format.
          
          Steve Mansour
          Judge, Jury, and Executioner
          Netscape, iPlanet
          501 E Middlfield Road
          Mountain View, CA 94043 USA
          Phone:  +1-408-276-4268
          mailto:sman@netscape.com
          
          Paul Hill
          Senior Programmer Analyst
          Massachusetts Institute of Technology
          W92-172
          77 Massachusetts Avenue
          Cambridge, MA, USA
          02139
          Phone:  +1-617-253-0124
          Fax: +1-617-258-8736
          mailto:pbh@mit.edu
          
          Doug Royer
          mailto:Doug@Royer.com
          
          George Babics
          Steltor (formerly CS&T/Lexacom)
          2000 Peel Street
          Montreal, Quebec, Canada
          H3A 2W5
          Tel: (514) 733-8500 x4201
          Fax: (514) 733-8878
          Mailto: georgeb@steltor.com
          
          18 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 Internet
          
          
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          organizations, except as needed for the purpose of developing
          Internet standards in which case the procedures for copyrights
          defined in the Internet Standards process MUST be followed, or
          as required to translate it into languages other than English.
          
          The limited permissions granted above are perpetual and will
          not be revoked by the Internet Society or its successors or
          assigns. This document and the information contained herein is
          provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE
          INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES,
          EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY
          THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY
          RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
          FOR A PARTICULAR PURPOSE.
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
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