SIPPING                                                     J. Rosenberg
Internet-Draft                                             Cisco Systems
Expires: September 19, 2005                               H. Schulzrinne
                                                     Columbia University
                                                           O. Levin, Ed.
                                                   Microsoft Corporation
                                                          March 18, 2005


    A Session Initiation Protocol (SIP) Event Package for Conference
                                 State
                draft-ietf-sipping-conference-package-10

Status of this Memo

   This document is an Internet-Draft and is subject to all provisions
   of Section 3 of RFC 3667.  By submitting this Internet-Draft, each
   author represents that any applicable patent or other IPR claims of
   which he or she is aware have been or will be disclosed, and any of
   which he or she become aware will be disclosed, in accordance with
   RFC 3668.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on September 19, 2005.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document defines a conference event package for the Session
   Initiation Protocol (SIP) Events framework, along with a data format



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   used in notifications for this package.  The conference package
   allows users to subscribe to a conference URI.  Notifications are
   sent about changes in the membership of this conference and
   optionally about changes in the state of additional conference
   components.

Table of Contents

   1.   Introduction . . . . . . . . . . . . . . . . . . . . . . . .   5
   2.   Terminology  . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.   Conference Event Package . . . . . . . . . . . . . . . . . .   5
     3.1  Event Package Name . . . . . . . . . . . . . . . . . . . .   5
     3.2  SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . .   6
     3.3  Subscription Duration  . . . . . . . . . . . . . . . . . .   6
     3.4  NOTIFY Bodies  . . . . . . . . . . . . . . . . . . . . . .   6
     3.5  Notifier Processing of SUBSCRIBE Requests  . . . . . . . .   7
     3.6  Notifier Generation of NOTIFY Requests . . . . . . . . . .   7
     3.7  Subscriber Processing of NOTIFY Requests . . . . . . . . .   7
     3.8  Handling of Forked Requests  . . . . . . . . . . . . . . .   8
     3.9  Rate of Notifications  . . . . . . . . . . . . . . . . . .   8
     3.10   State Agents . . . . . . . . . . . . . . . . . . . . . .   8
   4.   Conference Document  . . . . . . . . . . . . . . . . . . . .   8
     4.1  Format . . . . . . . . . . . . . . . . . . . . . . . . . .   8
     4.2  Namespace  . . . . . . . . . . . . . . . . . . . . . . . .   8
     4.3  Versioning . . . . . . . . . . . . . . . . . . . . . . . .   8
     4.4  Partial Notifications Mechanism Using 'state' Attribute  .   9
     4.5  Element Keys . . . . . . . . . . . . . . . . . . . . . . .  10
     4.6  Constructing Coherent State Procedure  . . . . . . . . . .  10
   5.   Conference Data  . . . . . . . . . . . . . . . . . . . . . .  11
     5.1  conference-type  . . . . . . . . . . . . . . . . . . . . .  11
       5.1.1  conference-description of
              conference-description-type  . . . . . . . . . . . . .  12
       5.1.2  host-info of host-type . . . . . . . . . . . . . . . .  12
       5.1.3  conference-state of conference-state-type  . . . . . .  12
       5.1.4  users of users-type  . . . . . . . . . . . . . . . . .  12
       5.1.5  sidebars-by-ref of uris-type . . . . . . . . . . . . .  13
       5.1.6  sidebar-by-val of conference-type  . . . . . . . . . .  13
     5.2  conference-description-type  . . . . . . . . . . . . . . .  13
       5.2.1  display-text of string type  . . . . . . . . . . . . .  13
       5.2.2  subject of string type . . . . . . . . . . . . . . . .  13
       5.2.3  free-text of string type . . . . . . . . . . . . . . .  13
       5.2.4  keywords of keywords-type  . . . . . . . . . . . . . .  13
       5.2.5  conf-uris of uris-type . . . . . . . . . . . . . . . .  13
       5.2.6  service-uris of uris-type  . . . . . . . . . . . . . .  14
       5.2.7  maximum-user-count of user-count-type  . . . . . . . .  14
       5.2.8  available-media of conference-media-type . . . . . . .  14
     5.3  host-type  . . . . . . . . . . . . . . . . . . . . . . . .  15
       5.3.1  display-text of string type  . . . . . . . . . . . . .  15



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       5.3.2  web-page of anyURI type  . . . . . . . . . . . . . . .  15
       5.3.3  uris of uris-type  . . . . . . . . . . . . . . . . . .  15
     5.4  conference-state-type  . . . . . . . . . . . . . . . . . .  15
       5.4.1  user-count of user-count-type  . . . . . . . . . . . .  15
       5.4.2  active of Boolean type . . . . . . . . . . . . . . . .  15
       5.4.3  locked of Boolean type . . . . . . . . . . . . . . . .  15
     5.5  conference-media-type  . . . . . . . . . . . . . . . . . .  16
       5.5.1  conference-medium-type . . . . . . . . . . . . . . . .  16
         5.5.1.1  display-text of string type  . . . . . . . . . . .  16
         5.5.1.2  type of string type  . . . . . . . . . . . . . . .  16
         5.5.1.3  status of media-status-type  . . . . . . . . . . .  16
     5.6  user-type  . . . . . . . . . . . . . . . . . . . . . . . .  16
       5.6.1  display-text of string type  . . . . . . . . . . . . .  17
       5.6.2  associated-aors of anyURI type . . . . . . . . . . . .  17
       5.6.3  roles of user-roles-type . . . . . . . . . . . . . . .  17
       5.6.4  language of language type  . . . . . . . . . . . . . .  17
       5.6.5  cascaded-focus of anyURI type  . . . . . . . . . . . .  17
       5.6.6  endpoint of endpoint-type  . . . . . . . . . . . . . .  18
     5.7  endpoint-type  . . . . . . . . . . . . . . . . . . . . . .  18
       5.7.1  display-text of string type  . . . . . . . . . . . . .  18
       5.7.2  referred of execution-type . . . . . . . . . . . . . .  19
       5.7.3  status of endpoint-status-type . . . . . . . . . . . .  19
       5.7.4  joining-method of joining-type . . . . . . . . . . . .  20
       5.7.5  joining-info of execution-type . . . . . . . . . . . .  20
       5.7.6  disconnection-method of disconnection-type . . . . . .  21
       5.7.7  disconnection-info of execution-type . . . . . . . . .  21
       5.7.8  media of media-type  . . . . . . . . . . . . . . . . .  21
       5.7.9  call-info of call-type . . . . . . . . . . . . . . . .  22
       5.7.10   media-type . . . . . . . . . . . . . . . . . . . . .  22
         5.7.10.1   display-text of string type  . . . . . . . . . .  22
         5.7.10.2   type of string type  . . . . . . . . . . . . . .  22
         5.7.10.3   label of string type . . . . . . . . . . . . . .  22
         5.7.10.4   src-id of string type  . . . . . . . . . . . . .  23
         5.7.10.5   status of media-status-type  . . . . . . . . . .  23
   6.   XML Schema . . . . . . . . . . . . . . . . . . . . . . . . .  23
   7.   Examples . . . . . . . . . . . . . . . . . . . . . . . . . .  31
     7.1  Basic Example  . . . . . . . . . . . . . . . . . . . . . .  31
     7.2  Rich Example . . . . . . . . . . . . . . . . . . . . . . .  33
   8.   Security Considerations  . . . . . . . . . . . . . . . . . .  37
   9.   IANA Considerations  . . . . . . . . . . . . . . . . . . . .  37
     9.1  conference Event Package Registration  . . . . . . . . . .  37
     9.2  application/conference-info+xml MIME Registration  . . . .  38
     9.3  URN Sub-Namespace Registration for
          urn:ietf:params:xml:ns:conference-info . . . . . . . . . .  38
     9.4  XML Schema Registration  . . . . . . . . . . . . . . . . .  39
     9.5  URI Purposes Sub-registry Establishment  . . . . . . . . .  39
   10.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . .  40
   11.  References . . . . . . . . . . . . . . . . . . . . . . . . .  40



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     11.1   Normative References . . . . . . . . . . . . . . . . . .  40
     11.2   Informative References . . . . . . . . . . . . . . . . .  41
        Authors' Addresses . . . . . . . . . . . . . . . . . . . . .  42
        Intellectual Property and Copyright Statements . . . . . . .  44















































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1.  Introduction

   The Session Initiation Protocol (SIP) [7]Events Framework [8] defines
   general mechanisms for subscribing to, and receiving notifications
   of, events within SIP networks.  It introduces the notion of a
   package, which is a specific "instantiation" of the events framework
   for a well-defined set of events.  Here, we define an event package
   for SIP conferences.  This package provides the conference
   notification service as outlined in the SIP conferencing framework
   [18].  As described there, subscriptions to a conference URI are
   routed to the focus that is handling the conference.  It acts as the
   notifier, and provides clients with updates on conference state.

   The information provided by this package is comprised of conference
   identifier(s), conference participants (optionally with their
   statuses and media description), conference sidebars, conference
   service URIs, etc.

2.  Terminology

   In this document, the key words "MUST", "MUST NOT", "REQUIRED",
   "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
   and "OPTIONAL" are to be interpreted as described in RFC 2119 [1] and
   indicate requirement levels for compliant implementations.

3.  Conference Event Package

   The conference event package allows a user to subscribe to a
   conference.  In SIP, conferences are represented by URIs.  These URIs
   route to a SIP user agent, called a focus, that is responsible for
   ensuring that all users in the conference can communicate with each
   other, as described in Conferencing Framework [18].  The focus has
   sufficient information about the state of the conference to inform
   subscribers about it.

   It is possible that a participant in the conference may in fact be
   another focus.  In order to provide a more complete participant list,
   the focus MAY subscribe to the conference package of the other focus
   to discover the participant list in the cascaded conference.  This
   information can then be included in notifications by use of the
   <cascaded-focus> element as specified by this package.

   This section provides the details for defining a SIP-specific event
   notification package, as specified by RFC 3265 [8].

3.1  Event Package Name

   The name of this event package is "conference".  This package name is



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   carried in the Event and Allow-Events header, as defined in RFC 3265
   [8].

3.2  SUBSCRIBE Bodies

   A SUBSCRIBE for a conference package MAY contain a body.  This body
   defines a filter to apply to the subscription.  Filter documents are
   not specified in this document, and at the time of writing, are
   expected to be the subject of future standardization activity.

   A SUBSCRIBE for a conference package MAY be sent without a body.
   This implies the default subscription filtering policy.  The default
   policy is:
   o  Notifications are generated every time there is any change in the
      state of the conference.
   o  Notifications do not normally contain full state; rather, they
      only indicate the state that has changed.  The exception is a
      NOTIFY sent in response to a SUBSCRIBE.  These NOTIFYs contain the
      full state of the information requested by the subscriber.

3.3  Subscription Duration

   The default expiration time for a subscription to a conference is one
   hour.  Once the conference ends, all subscriptions to that particular
   conference are terminated, with a reason of "noresource" as defined
   in RFC 3265 [8].

3.4  NOTIFY Bodies

   As described in RFC 3265 [8], the NOTIFY message will contain bodies
   that describe the state of the subscribed resource.  This body is in
   a format listed in the Accept header field of the SUBSCRIBE, or a
   package-specific default if the Accept header field was omitted from
   the SUBSCRIBE.

   In this event package, the body of the notification contains a
   conference information document.  This document describes the state
   of a conference.  All subscribers and notifiers MUST support the
   "application/conference-info+xml" data format described in Section 5.
   The subscribe request MAY contain an Accept header field.  If no such
   header field is present, it has a default value of
   "application/conference-info+xml".  If the header field is present,
   it MUST include "application/conference-info+xml", and MAY include
   any other types.

   Of course, the notifications generated by the server MUST be in one
   of the formats specified in the Accept header field in the SUBSCRIBE
   request.



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3.5  Notifier Processing of SUBSCRIBE Requests

   The conference information contains very sensitive information.
   Therefore, all subscriptions SHOULD be authenticated and then
   authorized before approval.  Authorization policy is at the
   discretion of the administrator, as always.  However, a few
   recommendations can be made.

   It is RECOMMENDED that all users in the conference be allowed to
   subscribe to the conference event package.

3.6  Notifier Generation of NOTIFY Requests

   Notifications SHOULD be generated for the conference state when a new
   participant joins (i.e.  gets "connected" to) or a participant leaves
   (i.e.  gets "disconnected" from) the conference.

   Subject to a local focus policy, additional changes in participants'
   status, changes in their media types, and other optional information
   MAY be reported by the focus.

   Changes in sidebar rosters SHOULD be reported by the focus to their
   participants and MAY be reported to others, subject to local policy.

   Changes in conference identifiers and service URIs SHOULD be reported
   by the focus to the Conference package subscribers.

   Changes in other conference state information MAY be reported by the
   focus to the Conference package subscribers.

3.7  Subscriber Processing of NOTIFY Requests

   The SIP Events framework expects packages to specify how a subscriber
   processes NOTIFY requests in any package specific ways, and in
   particular, how it uses the NOTIFY requests to construct a coherent
   view of the state of the subscribed resource.

   Typically, the NOTIFY for the conference package will only contain
   information about those users whose state in the conference has
   changed.  To construct a coherent view of the total state of all
   users, a subscriber to the conference package will need to combine
   NOTIFYs received over time.

   Notifications within this package can convey partial information;
   that is, they can indicate information about a subset of the state
   associated with the subscription.  This means that an explicit
   algorithm needs to be defined in order to construct coherent and
   consistent state.  The details of this mechanism are specific to the



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   particular document type.  See Section 4.6 for information on
   constructing coherent information from an
   application/conference-info+xml document.

3.8  Handling of Forked Requests

   By their nature, the conferences supported by this package are
   centralized.  Therefore, SUBSCRIBE requests for a conference should
   not generally fork.  Users of this package MUST NOT install more than
   a single subscription as a result of a single SUBSCRIBE request.

3.9  Rate of Notifications

   For reasons of congestion control, it is important that the rate of
   notifications not become excessive.  As a result, it is RECOMMENDED
   that the server doesn't generate notifications for a single
   subscriber at a rate faster than once every 5 seconds.

3.10  State Agents

   Conference state is ideally maintained in the element in which the
   conference resides.  Therefore, the elements that maintain the
   conference are the ones best suited to handle subscriptions to it.
   Therefore, the usage of state agents is NOT RECOMMENDED for this
   package.

4.  Conference Document

4.1  Format

   Conference information is an XML document that MUST be well-formed
   and valid.  It MUST be based on Extensible Markup Language (XML) 1.0
   and MUST be encoded using UTF-8 [13].

4.2  Namespace

   This specification makes use of XML namespaces for identifying
   conference information documents and document fragments.  The
   namespace URI for elements defined by this specification is a URN
   [2], using the namespace identifier 'ietf' defined by [5] and
   extended by RFC 3688 [14].  This URN is:

   urn:ietf:params:xml:ns:conference-info

4.3  Versioning

   The conference information is described by a hierarchal XML structure
   with the root element <conference-info>.  The root element is the



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   only element in the schema that carries meaningful version number for
   all the elements in the document.  The whole conference information
   is associated with this version number.

   The 'version' attribute MUST be included in the root
   <conference-info> element.

4.4  Partial Notifications Mechanism Using 'state' Attribute

   This specification defines a basic partial notifications mechanism
   that MUST be supported by all subscribing clients.  Additional
   general partial notifications mechanisms can be defined and applied
   to this package in the future.

   All sub-elements in the <conference-info> hierarchal XML structure
   can be classified in two groups: permissible to partial notifications
   or not.  Elements that carry a substantial amount of data that is
   subject to frequent changes are permissible to partial notifications
   and have a 'state' attribute attached to them.  All future extensions
   to this schema MUST define which extension elements can also use this
   mechanism.  All other elements can be updated as atomic pieces of
   data only.

   Below is the complete list of elements permissible to use the partial
   notifications mechanism defined in this specification.  (Note that
   future partial notifications mechanisms can potentially be applicable
   to additional elements.)

   o  Element <conference-info>
   o  Element <users>
   o  Element <user>
   o  Element <endpoint>
   o  Element <sidebars-by-val>
   o  Element <sidebars-by-ref>

   The 'state' attribute indicates whether the reported information
   about the element is "full", "partial" or the element is "deleted"
   from the conference state document.  The default value of any 'state'
   attribute is "full".

   A 'state' attribute of a child element in the document MUST adhere to
   its parent 'state'.  It means that if the parent's 'state' is "full",
   the state of its children MUST be "full".  If the parent's 'state' is
   "partial", the state of its children MAY be either "partial", "full",
   or "deleted".






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4.5  Element Keys

   The defined XML schema has a property of unique identification among
   sub-elements of a common parent, which is permissible to use the
   partial notifications mechanism defined in this document.  This
   property is achieved by defining a key to each sub-element with
   possible multiple appearances under the common parent.

   In the context of this specification, the element key is the set of
   mandatory attributes or sub-elements of an element.  The key value
   MUST be unique for the element among its siblings of the same type.

   Below is the list of elements (subject to partial notifications of
   their parent elements) with their keys as defined by this
   specification:

   o  Element <user> uses as the key 'entity'
   o  Element <endpoint> uses as the key 'entity'
   o  Element <media> uses as the key 'id'
   o  Element <entry> (child to <sidebars-by-val>) uses as the key
      'entity'
   o  Element <sidebars-by-ref> uses as the key <uri>

4.6  Constructing Coherent State Procedure

   A conference package subscriber locally maintains a local version
   number, a local element for each element in the schema, and a table
   for each element with key(s) in the schema.

   For first time a NOTIFY with a "full" document is received (as
   indicated by the value of the 'state' attribute in the
   <conference-info> element), the conference package subscriber MUST
   set the local 'version' number to the value of the 'version'
   attribute from the received <conference-info> and populate local data
   with the received information.

   Each time a new NOTIFY is received, the value of the local version
   number and the value of the 'version' attribute in the new received
   document are compared.  If the value in the document is equal or less
   than the local version, the document is discarded without processing.

   Otherwise, if the received NOTIFY contains a "full" or "deleted"
   state, the conference package subscriber MUST set the local 'version'
   number to the value of the 'version' attribute from the received
   <conference-info> and replace the local information with the received
   document.  Receiving "deleted" state means that the conference ceased
   to exist and the subscriber SHOULD terminate the subscription by
   sending the SUBSCRIBE with Expires = 0.



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   Otherwise (i.e.  if the received NOTIFY contains "partial" state), if
   the 'version' number in the received document is more than one number
   higher than the previous local version number, the subscriber MUST
   generate a refresh request to trigger a full state notification.  If
   the 'version' number in the document is one higher than the local
   version number, the local version number is updated accordingly and
   the document is used to update the local content as described below.

   For each sub-element of the <conference-info> element in the received
   document,

   1.  If the element contains "full" state, the whole local element
   content is flushed and repopulated from the document.

   2.  Otherwise, if the element contains "deleted" state, the whole
   element MUST be removed from the local content.

   3.  Otherwise, if the element contains "partial" state:

   3.1 For elements with keys, the subscriber compares the keys received
   in the update with the keys in the local tables.

   3.1.1 If a key does not exist in the local table, a row is added, and
   its content is set to the element information from the update.

   3.1.2 Otherwise, if a key of the same value does exist, for each
   sub-element in the row the algorithm is applied from step 3.2.

   3.2 For each atomic element received in the schema, the element is
   replaced with the new information as a whole.  Also, for each
   non-atomic element received in the schema with either no 'state'
   attribute included or the state attribute is set to "full", the
   element is replaced with the new information as a whole.

   3.3 For each non-atomic element with the state attribute set to
   "partial", the algorithm is applied recursively starting from step
   3.1.

5.  Conference Data

   A conference information document begins with the root element tag
   <conference-info> of conference-type.  Sections below describe the
   complex types composing the hierarchal conference-type.  The full XML
   schema is defined in Section 6.

5.1  conference-type

   This type defines the following attributes:



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   entity: This attribute contains the conference URI that identifies
      the conference being described in the document.

   state: This attribute indicates whether the document contains the
      whole conference information ("full"), only the information that
      has changed since the previous document ("partial"), or the
      conference ceased to exist ("deleted").  For more details see
      Section 4.
   version: This attribute allows the recipient of conference
      information documents to properly order them and it MUST be
      included when used in the root <conference-info> element.  Version
      number is a 32 bit monotonically increasing integer scoped within
      a subscription.  A server MUST increment the version number by one
      for each new partial notification being sent to a subscriber.

   The conference-type defines an extendable sequence of child elements.
   A "full" conference document MUST at least include the following
   sub-elements: <conference-description>, <conference-state>, and
   <users>.

   The child elements are described in details below:

5.1.1  conference-description of conference-description-type

   This element contains conference information that is derived from
   system conference policies, is set before the conference activation,
   and is rarely changed during the conference lifetime.

5.1.2  host-info of host-type

   This element contains information about the entity that hosts the
   conference.  This information is set before the conference
   activation, and is rarely changed during the conference lifetime,
   unless the whole conference is moved to be hosted by another entity.

5.1.3  conference-state of conference-state-type

   This element contains the dynamic information about the current state
   of the conference.

5.1.4  users of users-type

   This element can contain an unbounded number of <user> sub-elements
   of user-type each containing the information about a participant in
   the conference.





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5.1.5  sidebars-by-ref of uris-type

   This element contains <entry> sub-elements of uri-type which provide
   pointers to sidebar information through sidebar URIs.  The recipient
   of the information can then subscribe to sidebar information
   independently from the main conference package subscription.

5.1.6  sidebar-by-val of conference-type

   This element provides sidebar information as a part of the main
   conference package information.

5.2  conference-description-type

   This type defines an extendable sequence of the following child
   elements:

5.2.1  display-text of string type

   This element contains text description of the conference.

5.2.2  subject of string type

   This element contains the subject of the conference.

5.2.3  free-text of string type

   This element contains free form text about the conference.

5.2.4  keywords of keywords-type

   This element contains a list of words that can be used by automatic
   search engines to better classify the conference.

5.2.5  conf-uris of uris-type

   This element contains a set of <entry> sub-elements - each containing
   the information about an additional conference URI that this
   conference can be accessed by.  The value of the URI is included in
   the <uri> sub-element and its description MAY be included in the
   <display-text> sub-element.

   The purpose of the URI SHOULD be included in the <purpose>
   sub-element.  The currently defined <purpose> values to be used with
   the <conf-uris> are:






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   participation: Indicates that dialing into this URI will bring the
      party into the conference
   streaming: Indicates that "listening" to this URI will provide the
      conference live content

   Future extensions to this schema may define new values and register
   them with IANA under the registry established by this specification.

   Examples of such URIs include sip: / sips: [7], h323: [17], and tel:
   [16] URIs.

5.2.6  service-uris of uris-type

   This element contains a set of <entry> sub-elements - each containing
   the URI to be used in order to access different services available
   for the particular conference.  The value of the URI is included in
   the <uri> sub-element and its description MAY be included in the
   <display-text> sub-element.

   The purpose of the URI SHOULD be included in the <purpose>
   sub-element.  The currently defined <purpose> values to be used with
   the <service-uris> are:

   web-page: Indicates the web page containing the additional
      information about the conference
   recording: Indicates the link at which the recorded conference
      context can be retrieved
   event: Indicates the URI to which the subscription to the conference
      event package needs to be performed

   Future extensions to this schema may define new values and register
   them with IANA under the registry established by this specification.

5.2.7  maximum-user-count of user-count-type

   This element, if used, specifies the maximum number of users
   permitted in the conference and SHOULD include the counter for all
   participants in the conference in total by populating the attribute
   'role' with value "any".  Counters for users with specific roles MAY
   be additionally provided.

5.2.8  available-media of conference-media-type

   This element contains information about the media streams with their
   types available to the participants in the conference.  The entries
   in the <available-media> container are of conference-medium-type and
   are indexed by attribute 'label'.




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5.3  host-type

   This type defines an extendable sequence of the following child
   elements:

5.3.1  display-text of string type

   This element contains display text information about the entity
   hosting the conference.

5.3.2  web-page of anyURI type

   This element contains a web page URI about the user hosting the
   conference.

5.3.3  uris of uris-type

   The <entity> sub-element contains additional URIs pointing to the
   conference host.

5.4  conference-state-type

   This type defines an extendable sequence of the following child
   elements.

5.4.1  user-count of user-count-type

   This element is used to specify the current number of users in the
   conference.  The number SHOULD be provided for all participants in
   total by populating the <role> sub-element with value "any".
   Additionally counters for users with certain roles in the conference
   MAY be separately provided.

5.4.2  active of Boolean type

   This element says whether the conference is currently active or not.
   A conference is active if dialing into one of the <conf-uris> results
   in successful establishment of a call signaling session between the
   dialed user and the conference focus.

5.4.3  locked of Boolean type

   This element contains information about whether the conference is
   currently locked.  In this context, "locked" means that the
   conference roster can not be added to (although participants may
   leave or be removed from the conference).





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5.5  conference-media-type

   This type defines a sequence of <entry> child elements, each of
   conference-medium-type.

   This type defines an extendable sequence of the following child
   elements.

5.5.1  conference-medium-type

   This type defines the 'label' attribute, which is the media stream
   identifier being assigned by the conferencing server.  This value is
   unique in the conference context.  The value of this attribute MAY
   correspond to the SDP "label" media attribute defined in [21].

   This type defines an extendable sequence of the following child
   elements.

5.5.1.1  display-text of string type

   This element contains the display text for the media stream.

5.5.1.2  type of string type

   This element contains the media type of the media stream.  The value
   of this element MUST be one of the values registered for "media" of
   SDP [3] and its later revision(s).

5.5.1.3  status of media-status-type

   The element <status> indicates the status in both directions of the
   media stream and has the values "sendrecv", "sendonly", "recvonly",
   or "inactive" as defined in SDP [3] and its later revision(s).  Note
   that value specifies the direction from the participant's point of
   view.

5.6  user-type

   This type defines the following attributes:

   entity: This attribute contains the URI for the user in the
      conference.  This is a logical identifier, which corresponds to
      the authenticated identity of the participant.  The 'entity'
      attribute MUST be unique in the user element list because it is
      used as the key in partial notifications about users' state.  An
      anonymous participant in a conference SHOULD be represented by an
      anonymous URI generated by the focus.  For multiple anonymous
      participants, the focus must ensure that each anonymous URI is



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      unique.  The guidelines for generating anonymous URIs in RFC 3323
      [9] should be followed.  For example,

   "Anonymous1" <sip:anonymous1@anonymous.invalid>

       could be used for a participant requesting privacy.

   state: This attribute indicates whether the document contains the
      whole conference information ("full"), only the information that
      has changed since the previous document ("partial"), or the
      conference ceased to exist ("deleted").

   This type defines an extendable sequence of the following child
   elements.

5.6.1  display-text of string type

   This element contains the display text for the user.

5.6.2  associated-aors of anyURI type

   This element contains associated URIs of the user.  Usually this
   information will be manually provided by a system administrator
   showing the logical association between signaling entities otherwise
   independent.

5.6.3  roles of user-roles-type

   This element contains the roles of the user.

5.6.4  language of language type

   This element contains the language preference of the user.  This
   information can be automatically learned via call signaling or be
   manually set per participant.

5.6.5  cascaded-focus of anyURI type

   This element contains a conference URI (different from the main
   conference URI) for users that are connected to the main conference
   as a result of focus cascading.  In accordance with the SIP
   conferencing framework [18], this package allows for representation
   of peer-to-peer (i.e.  "flat") focus cascading only.  The actual
   cascading graph can not be deduced from the information provided in
   the package alone.  Advanced applications can construct the graph by
   subscribing to both this package and the Dialog Package [19] of each
   cascaded focus and correlating the relevant information.




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5.6.6  endpoint of endpoint-type

   This element contains information about an endpoint or/and a session
   of the parent <user>.  The <endpoint> element can have unbounded
   number of appearances for each user participating in the conference.

   The mandatory 'entity' key of an <endpoint> identifies either one of
   the user devices or one of the call signaling sessions of this user
   with the focus.

   In a conferencing system where authentication is performed per
   endpoint (rather than per user), a focus is not necessarily aware of
   the logical association of multiple endpoints under a common user.
   In this case, the focus would arrange the endpoints as belonging to
   separate users in the conference document.  Note, that typically in
   this case, a <user> would contain a single <endpoint> with
   corresponding 'entity' attributes having the same value, unless
   multiple call signaling sessions are taking place between the
   endpoint and the focus simultaneously.

   In a different case, due to privacy concerns for a participant, a
   focus may choose to shield the information about the participant's
   multiple endpoints from the third-party subscribers.  To do so, the
   focus MAY aggregate the multiple endpoints' information into a single
   <endpoint> element under the participant's  <user>.

5.7  endpoint-type

   This type defines the following attributes:

   entity: The value of this attribute MUST be a unique in the context
      of the <user>.  In SIP terms, this can be the Contact URI, GRUU,
      etc.

   state: This attribute indicates whether the element contains the
      whole endpoint information ("full"), only the information that has
      changed since the previous document ("partial"), or the endpoint
      has been deleted from the conference ("deleted").

   This type defines an extendable sequence of the following child
   elements.

5.7.1  display-text of string type

   This element contains the display text for the endpoint.






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5.7.2  referred of execution-type

   This element contains information about the user who's action
   resulted in this endpoint being brought into the conference (e.g.
   the SIP user identified by this URI sent a REFER to the focus).  It
   can contain the following sub-elements:

   when: This element contains the date and time that the endpoint was
      referred to the conference and SHOULD be expressed in Coordinated
      Universal Time (UTC) format.

   reason: This element contains the reason the endpoint was referred to
      the conference.

   by: This element contains the URI of the entity who caused the
      endpoint to be referred to the conference.

5.7.3  status of endpoint-status-type

   This element contains the status of the endpoint, and can assume the
   following values:

   connected: The endpoint is a participant in the conference.
      Depending on the media policies, he/she can send and receive media
      to and from other participants.

   disconnected: The endpoint is not a participant in the conference and
      no active dialog exists between the endpoint and the focus.

   on-hold: Active SIP dialog exists between an endpoint and a focus,
      but endpoint is "on-hold" for this conference, i.e.  neither
      he/she is "hearing" the conference mix, nor is his/her media being
      mixed in the conference.  As an example, the endpoint has asked to
      join the conference using SIP, but his/her participation is
      pending based on moderator approval.  In the meantime he/she is
      hearing music-on-hold or some other kind of related content.

   muted-via-focus: Active SIP dialog exists between an endpoint and a
      focus and the endpoint can "listen" to the conference, but
      endpoint's media is not being mixed into the conference.  Note
      that sometimes a subset of endpoint media streams can be muted by
      focus (such as poor quality video) while others (such as voice or
      IM) can still be active.  In this case, it is RECOMMENDED that the
      "aggregated" endpoint connectivity <status> reflects the status of
      the most active media.






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   pending: Endpoint is not yet in the session, but it is anticipated
      that he/she will join in the near future.

   alerting: A PSTN ALERTING or SIP 180 Ringing was returned for the
      outbound call, endpoint is being alerted.

   dialing-in: Endpoint is dialing into the conference, not yet in the
      roster (probably being authenticated).

   dialing-out: Focus has dialed out to connect the endpoint to the
      conference, but the endpoint is not yet in the roster (probably
      being authenticated).

   disconnecting: Focus is in the process of disconnecting endpoint
      (either DISCONNECT or BYE was sent to the endpoint).

   Note that the defined transient statuses (e.g., disconnecting,
   alerting, etc.) could generate a lot of notifications.
   Implementations MAY choose not to generate notifications on these to
   all participants if it will generate too much traffic.

5.7.4  joining-method of joining-type

   This element contains method by which the endpoint joined the
   conference, and can assume the following values:

   dialed-in: The endpoint dialed into the conference, i.e.  sent INVITE
      to the focus, which resulted in successful dialog establishment.

   dialed-out: The focus has brought the endpoint into the conference by
      sending a successful INVITE to the endpoint.

   focus-owner: The endpoint is the focus for this conference.  This
      status is used only when a participant's UA acts as a conference
      focus.

5.7.5  joining-info of execution-type

   This element contains information about how the endpoint joined and
   can contain the following sub-elements:

   when: This element contains the date and time that the endpoint
      joined the conference and SHOULD be expressed in Coordinated
      Universal Time (UTC).






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   reason: This element contains the reason the endpoint joined the
      conference.

   by: This element contains the URI of the entity who caused the
      endpoint to join the conference.

5.7.6  disconnection-method of disconnection-type

   This element contains method by which the endpoint departed the
   conference, and can assume the following values:

   departed: The endpoint sent a BYE, thus leaving the conference.

   booted: The endpoint was sent a BYE by the focus, booting him/her out
      of the conference.  Alternatively, the endpoint tried to dial into
      to conference but was rejected by the focus due to local policy.

   failed: The server tried to bring the endpoint into the conference,
      but its attempt to contact the specific endpoint resulted in a
      non-200 class final response.  Alternatively, the endpoint tried
      to dial into the conference without success due to technical
      reasons.

5.7.7  disconnection-info of execution-type

   This element contains information about the endpoint's departure from
   the conference and can contain the following sub-elements:

   when: This element contains the date and time that the endpoint
      departed the conference and SHOULD be expressed in Coordinated
      Universal Time (UTC).

   reason: This element contains the reason the endpoint departed the
      conference.  When known and meaningful, it is RECOMMENDED to
      include the information as conveyed/reported by the call signaling
      in the format defined by RFC 3326 [10].  For example,

   <reason>Reason: SIP ;cause=415 ;text="Unsupported Media Type"</reason>


   by: This element contains the URI of the entity who caused the
      endpoint to depart the conference.

5.7.8  media of media-type

   This element contains information about a media stream of the
   endpoint.  The element of the media-type can have an unbounded number



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   of appearances in the endpoint-type for each media stream of the
   endpoint.  Note, that if the <call-info> sub-element of the endpoint
   is not included by the server, it is possible that the media streams
   listed under the common endpoint were established by separate
   signaling sessions (i.e.  belong to different "calls" or "dialogs").

5.7.9  call-info of call-type

   The <call-info> element MAY be used for providing detailed call
   signaling information for a call being maintained between the
   endpoint and the focus.  Note, that privacy policies MUST be
   consulted before revealing this information to third-party
   participants.

   The <sip> sub-element contains the SIP dialog identifier of the
   endpoint's dialog with the focus.  The element includes sub-elements
   <display-text>, <call-id>, <to-tag>, <from-tag>.

   In future, the <call-info> element can be expanded to include call
   signaling protocol information for other protocols besides SIP.

5.7.10  media-type

   This type defines the following attribute:

   id: The attribute is the media stream identifier being generated by
      the notification server such as its value is unique in the
      endpoint context.  This attribute is the key to refer to a
      particular media stream in the conference document.

   This type defines an extendable sequence of the following child
   elements.

5.7.10.1  display-text of string type

   This element contains the display text for the media stream.

5.7.10.2  type of string type

   This element contains the media type for the media stream.  The value
   of this element MUST be one of the values registered for "media" of
   SDP [3] and its later revision(s).

5.7.10.3  label of string type

   The element <label> carries a unique identifier for this stream among
   all streams in the conference and is assigned by the focus.  The
   value of this element corresponds to the SDP "label" media attribute



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   defined in [21].

5.7.10.4  src-id of string type

   The <src-id> element, if applicable, carries the information about
   the actual source of the media.  For example, for RTP/RTCP [12] media
   streams, the value MUST contain the SSRC value generated by the
   endpoint for the stream it sends.

   When an RTP mixer generates a CSRC list according to RTP/RTCP [12],
   it inserts a list of the SSRC identifiers of the sources that
   contributed to the generation of a particular packet into the RTP
   header of that packet.  A quote from RFC 3550: "An example
   application is audio conferencing where a mixer indicates all the
   talkers whose speech was combined to produce the outgoing packet,
   allowing the receiver to indicate the current talker, even though all
   the audio packets contain the same SSRC identifier (that of the
   mixer)."

   If an RTP mixer compliant to the above is used, participants can
   perform an SSRC to user mapping and identify "a current speaker".

5.7.10.5  status of media-status-type

   The element <status> indicates the status in both directions of the
   media stream and has the values "sendrecv", "sendonly", "recvonly",
   or "inactive" as defined in SDP [3] and its later revision(s).  Note
   that value specifies the direction from the participant's point of
   view.  For example, a muted participant's stream will have the value
   of "recvonly".

6.  XML Schema



   <?xml version="1.0" encoding="UTF-8" ?>
   <xs:schema targetNamespace="urn:ietf:params:xml:ns:conference-info" xmlns:tns="urn:ietf:params:xml:ns:conference-info" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="urn:ietf:params:xml:ns:conference-info" elementFormDefault="qualified" attributeFormDefault="unqualified">
      <!--
             This import brings in the XML language attribute xml:lang
      -->
        <xs:import namespace="http://www.w3.org/XML/1998/namespace" schemaLocation="http://www.w3.org/2001/03/xml.xsd" />
      <!--
         CONFERENCE ELEMENT
      -->
      <xs:element name="conference-info" type="conference-type"/>
      <!--
         CONFERENCE TYPE
      -->



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      <xs:complexType name="conference-type">
         <xs:sequence>
           <xs:element name="conference-description" type="conference-description-type" minOccurs="0"/>
      	<xs:element name="host-info" type="host-type" minOccurs="0"/>
      	<xs:element name="conference-state" type="conference-state-type" minOccurs="0"/>
      	<xs:element name="users" type="users-type" minOccurs="0"/>
      	<xs:element name="sidebars-by-ref" type="uris-type" minOccurs="0"/>
      	<xs:element name="sidebars-by-val" type="sidebars-by-val-type" minOccurs="0"/>
      	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>
         <xs:attribute name="entity" type="xs:anyURI" use="required"/>
         <xs:attribute name="state" type="state-type" use="optional" default="full"/>
         <xs:attribute name="version" type="xs:unsignedInt" use="optional"/>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>
      <!--
         STATE TYPE
      -->
      <xs:simpleType name="state-type">
      	<xs:restriction base="xs:string">
      		<xs:enumeration value="full"/>
      		<xs:enumeration value="partial"/>
      		<xs:enumeration value="deleted"/>
      	</xs:restriction>
      </xs:simpleType>

      <!--
         CONFERENCE DESCRIPTION TYPE
      -->
      <xs:complexType name="conference-description-type">
         <xs:sequence>
      	<xs:element name="display-text" type="xs:string" minOccurs="0"/>
      	<xs:element name="subject" type="xs:string" minOccurs="0"/>
      	<xs:element name="free-text" type="xs:string" minOccurs="0"/>
      	<xs:element name="keywords" type="keywords-type" minOccurs="0"/>
      	<xs:element name="conf-uris" type="uris-type" minOccurs="0"/>

      	<xs:element name="service-uris" type="uris-type" minOccurs="0"/>
      	<xs:element name="maximum-user-count" type="user-count-type" minOccurs="0"/>
      	<xs:element name="available-media" type="conference-media-type" minOccurs="0"/>
    	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>
      <!--
         HOST TYPE
      -->
      <xs:complexType name="host-type">



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         <xs:sequence>
      	<xs:element name="display-text" type="xs:string" minOccurs="0"/>
      	<xs:element name="web-page" type="xs:anyURI" minOccurs="0"/>
      	<xs:element name="uris" type="uris-type" minOccurs="0"/>
      	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>
      <!--
         CONFERENCE STATE TYPE
      -->
      <xs:complexType name="conference-state-type">
         <xs:sequence>
           <xs:element name="user-count" type="user-count-type" minOccurs="0"/>
      	<xs:element name="active" type="xs:boolean" minOccurs="0"/>
      	<xs:element name="locked" type="xs:boolean" minOccurs="0"/>
      	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>


      <!--
         CONFERENCE MEDIA TYPE
      -->
      <xs:complexType name="conference-media-type">

         <xs:sequence>
      	<xs:element name="entry" type="conference-medium-type" maxOccurs="unbounded"/>
         </xs:sequence>

      <xs:anyAttribute namespace="##other"/>

      </xs:complexType>
      <!--
         CONFERENCE MEDIUM TYPE
      -->
      <xs:complexType name="conference-medium-type">
         <xs:sequence>
       	<xs:element name="display-text" type="xs:string"/>
      	<xs:element name="type" type="xs:string" minOccurs="0"/>
      	<xs:element name="status" type="media-status-type" minOccurs="0"/>
      	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>
         <xs:attribute name="label" type="xs:string" use="required"/>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>




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      <!--
         URIs TYPE
      -->
      <xs:complexType name="uris-type">
         <xs:sequence>
      	<xs:element name="entry" type="uri-type" maxOccurs="unbounded"/>
         </xs:sequence>

         <xs:attribute name="state" type="state-type" use="optional" default="full"/>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>
      <!--
         URI TYPE
      -->
      <xs:complexType name="uri-type">
         <xs:sequence>
      	<xs:element name="uri" type="xs:anyURI"/>
      	<xs:element name="display-text" type="xs:string" minOccurs="0"/>
      	<xs:element name="purpose" type="xs:string" minOccurs="0"/>
      	<xs:element name="modified" type="execution-type" minOccurs="0"/>
      	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>

         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>

      <!--
         USER COUNT TYPE

      -->
      <xs:complexType name="user-count-type">
         <xs:sequence>
      	<xs:element name="entry" type="count-type" maxOccurs="unbounded"/>
         </xs:sequence>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>
      <!--
         COUNT TYPE
      -->
      <xs:complexType name="count-type">
         <xs:sequence>
    	<xs:element name="count" type="xs:nonNegativeInteger"/>
      	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>
         <xs:attribute name="role" type="xs:string" use="required"/>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>
      <!--



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         KEWORDS TYPE
      -->
      <xs:simpleType name="keywords-type">
             <xs:list itemType="xs:string"/>
      </xs:simpleType>
      <!--
         USERS TYPE
      -->
      <xs:complexType name="users-type">
         <xs:sequence>
             <xs:element name="user" type="user-type" minOccurs="0" maxOccurs="unbounded"/>
      	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>

         </xs:sequence>

         <xs:attribute name="state" type="state-type" use="optional" default="full"/>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>
      <!--
         USER TYPE
      -->
      <xs:complexType name="user-type">
         <xs:sequence>
      	<xs:element name="display-text" type="xs:string" minOccurs="0"/>
      	<xs:element name="associated-aors" type="uris-type" minOccurs="0"/>
      	<xs:element name="roles" type="user-roles-type" minOccurs="0"/>
      	<xs:element name="language" type="xs:language" minOccurs="0"/>
      	<xs:element name="cascaded-focus" type="xs:anyURI" minOccurs="0"/>
      	<xs:element name="endpoint" type="endpoint-type" minOccurs="0" maxOccurs="unbounded"/>
      	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>

         <xs:attribute name="entity" type="xs:anyURI"/>
         <xs:attribute name="state" type="state-type" use="optional" default="full"/>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>
      <!--
         USER ROLES TYPE
      -->
      <xs:complexType name="user-roles-type">
         <xs:sequence>
      	<xs:element name="entry" type="xs:string" maxOccurs="unbounded"/>
         </xs:sequence>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>

      <!--
         ENDPOINT TYPE



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      -->
      <xs:complexType name="endpoint-type">
         <xs:sequence>
      	<xs:element name="display-text" type="xs:string" minOccurs="0"/>
      	<xs:element name="referred" type="execution-type" minOccurs="0"/>
      	<xs:element name="status" type="endpoint-status-type" minOccurs="0"/>
      	<xs:element name="joining-method" type="joining-type" minOccurs="0"/>
      	<xs:element name="joining-info" type="execution-type" minOccurs="0"/>
      	<xs:element name="disconnection-method" type="disconnection-type" minOccurs="0"/>
      	<xs:element name="disconnection-info" type="execution-type" minOccurs="0"/>
      	<xs:element name="media" type="media-type" minOccurs="0" maxOccurs="unbounded"/>
      	<xs:element name="call-info" type="call-type" minOccurs="0"/>
      	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>

         <xs:attribute name="entity" type="xs:string"/>
         <xs:attribute name="state" type="state-type" use="optional" default="full"/>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>
      <!--
         ENDPOINT STATUS TYPE
      -->
      <xs:simpleType name="endpoint-status-type">
      	<xs:restriction base="xs:string">
      		<xs:enumeration value="pending"/>
      		<xs:enumeration value="dialing-out"/>
      		<xs:enumeration value="dialing-in"/>
      		<xs:enumeration value="alerting"/>

      		<xs:enumeration value="on-hold"/>
      		<xs:enumeration value="connected"/>
      		<xs:enumeration value="muted-via-focus"/>
      		<xs:enumeration value="disconnecting"/>
      		<xs:enumeration value="disconnected"/>
      	</xs:restriction>
      </xs:simpleType>
      <!--
         JOINING TYPE
      -->
      <xs:simpleType name="joining-type">
      	<xs:restriction base="xs:string">
      		<xs:enumeration value="dialed-in"/>
      		<xs:enumeration value="dialed-out"/>
      		<xs:enumeration value="focus-owner"/>
      	</xs:restriction>
      </xs:simpleType>
      <!--
         DISCONNECTION TYPE



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      -->

      <xs:simpleType name="disconnection-type">
             <xs:restriction base="xs:string">
      		<xs:enumeration value="departed"/>
      		<xs:enumeration value="booted"/>

      		<xs:enumeration value="failed"/>
      	</xs:restriction>

      </xs:simpleType>

      <!--
         EXECUTION TYPE
      -->
      <xs:complexType name="execution-type">
         <xs:sequence>
      	<xs:element name="when" type="xs:dateTime" minOccurs="0"/>
      	<xs:element name="reason" type="xs:string" minOccurs="0"/>
      	<xs:element name="by" type="xs:anyURI" minOccurs="0"/>
         </xs:sequence>

         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>

     <!--
         CALL TYPE
      -->
      <xs:complexType name="call-type">
         <xs:choice>
      	<xs:element name="sip" type="sip-dialog-id-type"/>
      	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
         </xs:choice>

         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>

      <!--
         SIP DIALOG ID TYPE
      -->
      <xs:complexType name="sip-dialog-id-type">
         <xs:sequence>
      	<xs:element name="display-text" type="xs:string" minOccurs="0"/>
      	<xs:element name="call-id" type="xs:string"/>
      	<xs:element name="from-tag" type="xs:string"/>
      	<xs:element name="to-tag" type="xs:string"/>
      	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>



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         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>

      <!--
         MEDIA TYPE
      -->
      <xs:complexType name="media-type">
         <xs:sequence>
   	<xs:element name="display-text" type="xs:string" minOccurs="0"/>
      	<xs:element name="type" type="xs:string" minOccurs="0"/>
      	<xs:element name="label" type="xs:string" minOccurs="0"/>
     	<xs:element name="src-id" type="xs:string" minOccurs="0"/>
      	<xs:element name="status" type="media-status-type" minOccurs="0"/>
      	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>
         <xs:attribute name="id" type="xs:string" use="required"/>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>

      <!--
         MEDIA STATUS TYPE
      -->
      <xs:simpleType name="media-status-type">
      	<xs:restriction base="xs:string">
      		<xs:enumeration value="recvonly"/>
      		<xs:enumeration value="sendonly"/>
      		<xs:enumeration value="sendrecv"/>
      		<xs:enumeration value="inactive"/>
      	</xs:restriction>
      </xs:simpleType>


       <!--
         SIDEBARS BY VAL TYPE
      -->

      <xs:complexType name="sidebars-by-val-type">
         <xs:sequence>
      	<xs:element name="entry" type="conference-type" minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>

         <xs:attribute name="state" type="state-type" use="optional" default="full"/>
         <xs:anyAttribute namespace="##other"/>
      </xs:complexType>

      </xs:schema>





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7.  Examples

7.1  Basic Example

   The following is an example conference information document:


   <conference-info entity="sips:conf233@example.com" state="partial" version="5" >
   <!--
      CONFERENCE INFO
   -->
      <conference-description>
   	<subject>Agenda: This month's goals</subject>
   	<service-uris>
   		<entry>
   			<uri> http://sharepoint/salesgroup/</uri>
   			<purpose>web-page</purpose>
   		</entry>
   	</service-uris>
      </conference-description>

   <!--
      CONFERENCE STATE
   -->
      <conference-state>
   	<user-count>
   		<entry role="any">
   				<count>33</count>
   		</entry>
   	</user-count>
      </conference-state>

      <users>
      <!--
          USER
      -->
   	<user entity="sip:bob@example.com" state="full">
   		<display-text>Bob Hoskins</display-text>
   		<!--
   	  		ENDPOINTS
   		-->
   		<endpoint entity="sip:bob@pc33.example.com">
   			<display-text>Bob's Laptop</display-text>
   			<status>disconnected</status>
   			<disconnection-method>departed</disconnection-method>
   			<disconnection-info>
   				<when>2005-03-04T20:00:00Z</when>
   				<reason>bad voice quality</reason>



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   				<by>sip:mike@example.com</by>
   			</disconnection-info>
   			<!--
   	  			MEDIA
   			-->
   			<media id="1">
   				<display-text>main audio</display-text>
   				<type>audio</type>
   				<label>34567</label>
   				<src-id>432424</src-id>

   				<status>sendrecv</status>
   			</media>
   		</endpoint>
   	</user>

      <!--
   	USER
      -->
          <user entity="sip:alice@example.net" state="full">
          		<display-text>Alice</display-text>
          		<!--
   			ENDPOINTS
   		-->
   	 	<endpoint entity="sip:4kfk4j392jsu@example.net;grid=433kj4j3u" call="1">
   	 		<status>connected</status>
   	 		<joining-method>dialed-out</joining-method>
   	 		<joining-info>
   				<when>2005-03-04T20:00:00Z</when>
   				<by>sip:mike@example.com</by>
   	 		</joining-info>
   			<!--
   	  			MEDIA
    			-->
    			<media id="1">
   				<display-text>main audio</display-text>
   				<type>audio</type>
     				<label>34567</label>
    				<src-id>534232</src-id>
    				<status>sendrecv</status>
    			</media>
          		</endpoint>

          </user>
      </users>

   </conference-info>




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7.2  Rich Example

   The following is an example conference information document.  In this
   example of a partial state notification, there are 32 participants in
   a voice conference.  The user Bob has been booted from the conference
   by Mike due to bad voice quality.  Note that there are three sidebars
   in the conference, two are referenced just by their sidebar URIs and
   information about the third sidebar is included in this notification.
   Also note that while this conference offers both audio and video
   capabilities, only audio is currently in use.



   <conference-info entity="sips:conf233@example.com" state="partial" version="5" >
      <!--
   	CONFERENCE INFO
      -->
   	<conference-description>
   		<display-text>Weekly Sales Meeting</display-text>
   		<subject>Agenda: This month's goals</subject>
   		<free-text>We will start strict on time</free-text>

   		<keywords>sales, meeting, weekly</keywords>
   		<conf-uris>
   			<entry>
   				<uri>tel:+18005671234</uri>
   				<display-text>TTI Bridge</display-text>
   				<purpose>participation</purpose>

   			</entry>

   			<entry>
   				<uri>h323:conf545@h323.example.com</uri>
   				<purpose>participation</purpose>
   			</entry>
   			<entry>
      	<uri>http://real.streaming.com/54634/live.ram</uri>
   				<purpose>streaming</purpose>
   			</entry>

   		</conf-uris>
   		<service-uris>
   			<entry>
   				<uri>http://sharepoint/salesgroup/</uri>
   				<purpose>web-page</purpose>
   			</entry>
   			<entry>
   	<uri>http://quicktime.com/54634/recording.mov</uri>



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   				<display-text>Quicktime</display-text>
   				<purpose>recording</purpose>
   			</entry>
   		</service-uris>
   		<maximum-user-count>
   			<entry role="any">
   				<count>52</count>
   			</entry>
   			<entry role="participant">
   				<count>50</count>
   			</entry>
   		</maximum-user-count>
   		<available-media>
   			<entry label="34567">
   				<display-text>main audio</display-text>
   				<type>audio</type>
   				<status>sendrecv</status>
   			</entry>
   			<entry label="34569">
   				<display-text>main video</display-text>
   				<type>video</type>
   				<status>inactive</status>
   			</entry>
   		</available-media>
   	</conference-description>
   	<!--

   	  HOST INFO
   	-->
   	<host-info>
   		<display-text>Sales Host</display-text>
   		<web-page>http://sharepoint/salesgroup/hosts/</web-page>
   		<uris>
   			<entry>
   				<uri>sip:sales@example.com</uri>
   			</entry>
   		</uris>
   	</host-info>
   	<!--
   	  CONFERENCE STATE
   	-->
   	<conference-state>
   		<user-count>
   			<entry role="any">
   				<count>33</count>
   			</entry>
   			<entry role="participant">
   				<count>32</count>



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   			</entry>
   		</user-count>
   		<active>true</active>
   		<locked>false</locked>

   	</conference-state>

   	<!--
   	USERS
   	-->
   	<users>
   		<user entity="sip:bob@example.com">
   			<display-text>Bob Hoskins</display-text>
   			<associated-aors>
   				<entry>
   					<uri>mailto:bob@example.com</uri>
   					<display-text>email</display-text>

   				</entry>
   			</associated-aors>
   			<roles>
   				<entry>participant</entry>
   			</roles>
   			<language>en</language>

   		<!--
   	  	ENDPOINTS
   		-->
   			<endpoint entity="sip:bob@pc33.example.com">
   				<display-text>Bob's Laptop</display-text>
   				<referred>
   					<when>2005-03-04T20:00:00Z</when>
   					<reason>expert required</reason>
   					<by>sip:mike@example.com</by>
   				</referred>
   				<status>disconnecting</status>
   				<joining-method>dialed-out</joining-method>
   				<joining-info>

   					<when>2005-03-04T20:00:00Z</when>
   					<reason>invitation</reason>
   					<by>sip:mike@example.com</by>
   				</joining-info>
   				<disconnection-method>booted</disconnection-method>
   				<disconnection-info>
   					<when>2005-03-04T20:00:00Z</when>
   					<reason>bad voice quality</reason>
   					<by>sip:mike@example.com</by>



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   				</disconnection-info>
   			<!--
   	  		CALL INFO
   			-->
   				<call-info>
   					<sip>
   					   <display-text>full info</display-text>
   					   <call-id>hsjh8980vhsb78</call-id>
   					   <from-tag>vav738dvbs</from-tag>
   					   <to-tag>8954jgjg8432</to-tag>
   					</sip>
   				</call-info>
   			<!--
   	  		MEDIA

   			-->
   				<media id="1">
   					<display-text>main audio</display-text>
   					<type>audio</type>
   					<label>34567</label>
   					<src-id>432424</src-id>
   					<status>sendrecv</status>
   				</media>
   			</endpoint>
   		</user>
   	</users>

   	<!--
   	SIDEBARS BY REFERENCE
   	-->
   	<sidebars-by-ref state="partial">
   		<entry>
   			<uri>sips:conf233@example.com; grid=45</uri>
   			<display-text>sidebar with Carol</display-text>
   		</entry>
   		<entry>
   			<uri>sips:conf233@example.com; grid=21</uri>
   			<display-text>private sidebar with Peter</display-text>
   		</entry>
   	</sidebars-by-ref>

   	<!--
   	SIDEBARS BY VALUE
   	-->
   	<sidebars-by-val state="partial">
   		<entry entity="sips:conf233@example.com; grid=77" state="partial">
   			<users>
   				<user entity="sip:bob@example.com"></user>



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   				<user entity="sip:mark@example.com"></user>
   				<user entity="sip:dan@example.com"></user>
   			</users>
   		</entry>
   	</sidebars-by-val>

   </conference-info>


8.  Security Considerations

   Subscriptions to conference state can reveal very sensitive
   information.  For this reason, the document recommends authentication
   and authorization, and provides guidelines on sensible authorization
   policies.

   Since the data in notifications is sensitive as well, end-to-end SIP
   encryption mechanisms using S/MIME SHOULD be used to protect it.

   Since a focus provides participant identity information using this
   event package, participant privacy needs to be taken into account.  A
   focus MUST support requests by participants for privacy.  Privacy can
   be indicated by the conference policy - for every participant or
   select participants.  It can also be indicated in the session
   signaling.  In SIP this can be done using the Privacy header field
   described in RFC 3323 [9].  For a participant requesting privacy, no
   identity information SHOULD be revealed by the focus such as a URI
   (e.g.  the Address of Record, Contact, or GRUU).  For these cases,
   the anonymous URI generation method outlined in section Section 5.6
   of this document MUST be followed.

9.  IANA Considerations

   This document registers a SIP event package, a new MIME type,
   application/conference-info+xml, a new XML namespace, a new XML
   schema, and creates a  sub-registry "URI purposes" under the
   existing registry: http://www.iana.org/assignments/sip-parameters.

9.1  conference Event Package Registration

   This specification registers an event package, based on the
   registration procedures defined in RFC 3265 [8].  The following is
   the information required for such a registration:
   Package Name: conference
   Package or Template-Package: This is a package.






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   Published Document: RFC XXXX (Note to RFC Editor: Please fill in XXXX
      with the RFC number of this specification).
   Person to Contact: Jonathan Rosenberg, jdrosen@jdrosen.net.

9.2  application/conference-info+xml MIME Registration
   MIME media type name: application
   MIME subtype name: conference-info+xml
   Mandatory parameters: none
   Optional parameters: Same as charset parameter application/xml as
      specified in RFC 3023 [6]
   Encoding considerations: Same as encoding considerations of
      application/xml as specified in RFC 3023 [6]
   Security considerations: See Section 10 of RFC 3023 [6] and Section 8
      of this specification
   Interoperability considerations: none
   Published specification: This document
   Applications which use this media type: This document type has been
      used to support SIP conferencing applications
   Additional Information:
      Magic Number: None
      File Extension: .cif or .xml
      Macintosh file type code: "TEXT"
   Personal and email address for further information: Jonathan
      Rosenberg, <jdrosen@jdrosen.net>
   Intended usage: COMMON
   Author/Change controller: The IETF

9.3  URN Sub-Namespace Registration for
    urn:ietf:params:xml:ns:conference-info

   This section registers a new XML namespace, as per the guidelines in
   RFC 3688 [14].

   URI: The URI for this namespace is
      urn:ietf:params:xml:ns:conference-info
   Registrant Contact: IETF, SIPPING working group, <sipping@ietf.org>,
      Jonathan Rosenberg <jdrosen@jdrosen.net>
   XML:













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   BEGIN
   <?xml version="1.0"?>
   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"
             "http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
   <html xmlns="http://www.w3.org/1999/xhtml">
   <head>
     <meta http-equiv="content-type"
        content="text/html;charset=iso-8859-1"/>
     <title>Conference Information Namespace</title>

   </head
   <body>
     <h1>Namespace for Conference Information</h1>
     <h2>urn:ietf:params:xml:ns:conference-info</h2>
     <p>See <a href="[[[URL of published RFC]]]">RFCXXXX</a>.</p>
   </body>
   </html>
   END


9.4  XML Schema Registration

   This specification registers a schema, as per the guidelines in RFC
   3688 [14].
      URI: please assign
      Registrant Contact: IETF, SIPPING Working Group
      (sipping@ietf.org), Jonathan Rosenberg (jdrosen@jdrosen.net)
      XML: The XML can be found as the sole content of Section 6

9.5  URI Purposes Sub-registry Establishment

   This document instructs the IANA to create a new sub-registry "URI
   purposes" under the already existing registry:
   http://www.iana.org/assignments/sip-parameters.

   The purpose of a URI is an XML element, encoded in the conference
   event package [RFC XXXX - substitute with the number assigned to this
   draft].  The value of the <purpose> element indicates the intended
   usage of the URI in the context of the conference event package and
   is defined in sections Section 5.2.5 and Section 5.2.6 of this
   specification.

   This sub-registry is defined as a table that contains the following
   three columns:







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   Value: The token under registration
   Description: A descriptive text defining the intended usage of the
      URI
   Document: A reference to the document defining the registration

   This specification instructs IANA to create the table with the
   initial content as defined below:


   Value         Description                         Document
   -------       ----------------------------------  ----------

   participation The URI can be used to join the     [RFC XXXX]
                 conference

   streaming     The URI can be used to access the   [RFC XXXX]
                 streamed conference data

   event         The URI can be used to subscribe    [RFC XXXX]
                 to the conference event package

   recording     The URI can be used to access the   [RFC XXXX]
                 recorded conference data

   web-page      The URI can be used to access a     [RFC XXXX]
                 web page that contains additional
                 information of the conference


   New values of the "URI purposes" are registered by the IANA when a
   specification becomes available and according to the definition of
   RFC 2434 [4].  The IANA Considerations section of the specification
   MUST include the following information:

   Value: The value of the <purpose> element to be registered
   Description: A short description of the intended usage of the URI

10.  Acknowledgements

   The authors would like to thank Dan Petrie, Sean Olson, Alan
   Johnston, Rohan Mahy, Cullen Jennings, Brian Rosen, Roni Even, and
   Miguel Garcia for their comments and inputs.

11.  References

11.1  Normative References

   [1]   Bradner, S., "Key words for use in RFCs to Indicate Requirement



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         Levels", BCP 14, RFC 2119, March 1997.

   [2]   Moats, R., "URN Syntax", RFC 2141, May 1997.

   [3]   Handley, M. and V. Jacobson, "SDP: Session Description
         Protocol", RFC 2327, April 1998.

   [4]   Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
         Considerations Section in RFCs", BCP 26, RFC 2434, October
         1998.

   [5]   Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
         August 1999.

   [6]   Murata, M., St. Laurent, S. and D. Kohn, "XML Media Types",
         RFC 3023, January 2001.

   [7]   Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
         Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP:
         Session Initiation Protocol", RFC 3261, June 2002.

   [8]   Roach, A., "Session Initiation Protocol (SIP)-Specific Event
         Notification", RFC 3265, June 2002.

   [9]   Peterson, J., "A Privacy Mechanism for the Session Initiation
         Protocol (SIP)", RFC 3323, November 2002.

   [10]  Schulzrinne, H., Oran, D. and G. Camarillo, "The Reason Header
         Field for the Session Initiation Protocol (SIP)", RFC 3326,
         December 2002.

   [11]  Camarillo, G., Eriksson, G., Holler, J. and H. Schulzrinne,
         "Grouping of Media Lines in the Session Description Protocol
         (SDP)", RFC 3388, December 2002.

   [12]  Schulzrinne, H., Casner, S., Frederick, R. and V. Jacobson,
         "RTP: A Transport Protocol for Real-Time Applications", STD 64,
         RFC 3550, July 2003.

   [13]  Yergeau, F., "UTF-8, a transformation format of ISO 10646",
         STD 63, RFC 3629, November 2003.

   [14]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
         January 2004.

11.2  Informative References

   [15]  Schulzrinne, H., Rao, A. and R. Lanphier, "Real Time Streaming



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         Protocol (RTSP)", RFC 2326, April 1998.

   [16]  Schulzrinne, H., "The tel URI for Telephone Numbers", RFC 3966,
         December 2004.

   [17]  Levin, O., "H.323 Uniform Resource Locator (URL) Scheme
         Registration", RFC 3508, April 2003.

   [18]  Rosenberg, J., "A Framework for Conferencing with the Session
         Initiation Protocol",
         Internet-Draft draft-ietf-sipping-conferencing-framework-04,
         February 2005.

   [19]  Rosenberg, J., "An INVITE Inititiated Dialog Event Package for
         the Session Initiation  Protocol (SIP)",
         Internet-Draft draft-ietf-sipping-dialog-package-05, November
         2004.

   [20]  Rosenberg, J., "Obtaining and Using Globally Routable User
         Agent (UA) URIs (GRUU) in the  Session Initiation Protocol
         (SIP)", Internet-Draft draft-ietf-sip-gruu-03, February 2005.

   [21]  Levin, O. and G. Camarillo, "The SDP (Session Description
         Protocol) Label Attribute",
         Internet-Draft draft-ietf-mmusic-sdp-media-label-01, January
         2005.


Authors' Addresses

   Jonathan Rosenberg
   Cisco Systems
   600 Lanidex Plaza
   Parsippany, NJ  07054
   US

   Phone: +1 973 952-5000
   Email: jdrosen@cisco.com
   URI:   http://www.jdrosen.net












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   Henning Schulzrinne
   Columbia University
   M/S 0401
   1214 Amsterdam Ave.
   New York, NY  10027
   US

   Email: schulzrinne@cs.columbia.edu
   URI:   http://www.cs.columbia.edu/~hgs


   Orit Levin (editor)
   Microsoft Corporation
   One Microsoft Way
   Redmond, WA  98052
   US

   Email: oritl@microsoft.com

































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