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SIPPING                                                     J. Rosenberg
Internet-Draft                                             Cisco Systems
Expires: May 28, 2005                                     H. Schulzrinne
                                                     Columbia University
                                                           O. Levin, Ed.
                                                   Microsoft Corporation
                                                       November 27, 2004


    A Session Initiation Protocol (SIP) Event Package for Conference
                                 State
                draft-ietf-sipping-conference-package-07

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
   Task Force (IETF), its areas, and its working groups.  Note that
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   Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
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   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.

   This Internet-Draft will expire on May 28, 2005.

Copyright Notice

   Copyright (C) The Internet Society (2004).

Abstract

   This document defines a conference event package for the Session
   Initiation Protocol (SIP) Events framework, along with a data format
   used in notifications for this package.  The conference package



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   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 . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  5
   3.  Conference Event Package . . . . . . . . . . . . . . . . . . .  6
     3.1   Event Package Name . . . . . . . . . . . . . . . . . . . .  6
     3.2   SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . .  6
     3.3   Subscription Duration  . . . . . . . . . . . . . . . . . .  6
     3.4   NOTIFY Bodies  . . . . . . . . . . . . . . . . . . . . . .  7
     3.5   Notifier Processing of SUBSCRIBE Requests  . . . . . . . .  7
     3.6   Notifier Generation of NOTIFY Requests . . . . . . . . . .  7
     3.7   Subscriber Processing of NOTIFY Requests . . . . . . . . .  8
     3.8   Handling of Forked Requests  . . . . . . . . . . . . . . .  8
     3.9   Rate of Notifications  . . . . . . . . . . . . . . . . . .  8
     3.10  State Agents . . . . . . . . . . . . . . . . . . . . . . .  8
   4.  Conference Document  . . . . . . . . . . . . . . . . . . . . . 10
     4.1   Format . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     4.2   Namespace  . . . . . . . . . . . . . . . . . . . . . . . . 10
     4.3   Versioning . . . . . . . . . . . . . . . . . . . . . . . . 10
     4.4   State and Partial Notifications  . . . . . . . . . . . . . 10
     4.5   Element Keys . . . . . . . . . . . . . . . . . . . . . . . 11
     4.6   Constructing Coherent State Procedure  . . . . . . . . . . 11
   5.  Conference Data  . . . . . . . . . . . . . . . . . . . . . . . 13
     5.1   conference-type  . . . . . . . . . . . . . . . . . . . . . 13
       5.1.1   conference-description of
               conference-description-type  . . . . . . . . . . . . . 13
       5.1.2   host-info of host-type . . . . . . . . . . . . . . . . 13
       5.1.3   conference-state of conference-state-type  . . . . . . 14
       5.1.4   users of users-type  . . . . . . . . . . . . . . . . . 14
       5.1.5   sidebars-by-ref of uris-type . . . . . . . . . . . . . 14
       5.1.6   sidebar-by-val of conference-type  . . . . . . . . . . 14
     5.2   conference-description-type  . . . . . . . . . . . . . . . 14
       5.2.1   display-text of string type  . . . . . . . . . . . . . 14
       5.2.2   subject of string type . . . . . . . . . . . . . . . . 14
       5.2.3   free-text of string type . . . . . . . . . . . . . . . 14
       5.2.4   keywords of keywords-type  . . . . . . . . . . . . . . 14
       5.2.5   conf-uris of uris-type . . . . . . . . . . . . . . . . 15
       5.2.6   service-uris of uris-type  . . . . . . . . . . . . . . 15
       5.2.7   maximum-user-count of user-count-type  . . . . . . . . 15
       5.2.8   available-media of conference-medias-type  . . . . . . 15
     5.3   host-type  . . . . . . . . . . . . . . . . . . . . . . . . 15
       5.3.1   display-text of string type  . . . . . . . . . . . . . 15
       5.3.2   web-page of anyURI type  . . . . . . . . . . . . . . . 16



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       5.3.3   uris of uris-type  . . . . . . . . . . . . . . . . . . 16
     5.4   conference-state-type  . . . . . . . . . . . . . . . . . . 16
       5.4.1   user-count of user-count-type  . . . . . . . . . . . . 16
       5.4.2   active of Boolean type . . . . . . . . . . . . . . . . 16
       5.4.3   locked of Boolean type . . . . . . . . . . . . . . . . 16
       5.4.4   recording of uris-type . . . . . . . . . . . . . . . . 16
       5.4.5   active-media of conference-medias-type . . . . . . . . 17
     5.5   user-type  . . . . . . . . . . . . . . . . . . . . . . . . 17
       5.5.1   display-text of string type  . . . . . . . . . . . . . 17
       5.5.2   associated-aors of anyURI type . . . . . . . . . . . . 17
       5.5.3   roles of user-roles-type . . . . . . . . . . . . . . . 17
       5.5.4   language of language type  . . . . . . . . . . . . . . 18
       5.5.5   cascaded-focus of anyURI type  . . . . . . . . . . . . 18
       5.5.6   endpoint of endpoint-type  . . . . . . . . . . . . . . 18
     5.6   endpoint-type  . . . . . . . . . . . . . . . . . . . . . . 18
       5.6.1   display-text of string type  . . . . . . . . . . . . . 19
       5.6.2   referred of execution-type . . . . . . . . . . . . . . 19
       5.6.3   status of endpoint-status-type . . . . . . . . . . . . 19
       5.6.4   joining-method of joining-type . . . . . . . . . . . . 20
       5.6.5   joining-info of execution-type . . . . . . . . . . . . 21
       5.6.6   disconnection-method of disconnection-type . . . . . . 21
       5.6.7   disconnection-info of execution-type . . . . . . . . . 21
       5.6.8   media of media-type  . . . . . . . . . . . . . . . . . 22
     5.7   media-type . . . . . . . . . . . . . . . . . . . . . . . . 22
       5.7.1   display-text of string type  . . . . . . . . . . . . . 22
       5.7.2   proto of string type . . . . . . . . . . . . . . . . . 22
       5.7.3   src-id of string type  . . . . . . . . . . . . . . . . 22
       5.7.4   label of string type . . . . . . . . . . . . . . . . . 23
       5.7.5   status of media-status-type  . . . . . . . . . . . . . 23
       5.7.6   call of call-type  . . . . . . . . . . . . . . . . . . 23
   6.  XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 24
   7.  Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
     7.1   Basic Example  . . . . . . . . . . . . . . . . . . . . . . 32
     7.2   Rich Example . . . . . . . . . . . . . . . . . . . . . . . 34
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 39
   9.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 40
     9.1   conference Event Package Registration  . . . . . . . . . . 40
     9.2   application/conference-info+xml MIME Registration  . . . . 40
     9.3   URN Sub-Namespace Registration for
           urn:ietf:params:xml:ns:conference-info . . . . . . . . . . 40
     9.4   XML Schema Registration  . . . . . . . . . . . . . . . . . 41
   10.   Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 42
   11.   References . . . . . . . . . . . . . . . . . . . . . . . . . 43
   11.1  Normative References . . . . . . . . . . . . . . . . . . . . 43
   11.2  Informative References . . . . . . . . . . . . . . . . . . . 43
       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 44
       Intellectual Property and Copyright Statements . . . . . . . . 46




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1.  Introduction

   The Session Initiation Protocol (SIP) [6] Events framework Events
   Framework [7] 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 [16].  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.

































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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.













































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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 [16].  The focus has
   sufficient information about the state of the conference to inform
   subscribers about it.

   It is possible 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 using of the
   <cascaded-focus> element as specified by this package.

   This section provides the details for defining a SIP Events package,
   as specified by RFC 3265 [7].

3.1  Event Package Name

   The name of this event package is "conference".  This package name is
   carried in the Event and Allow-Events header, as defined in RFC 3265
   [7].

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" RFC 3265



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   [7].

3.4  NOTIFY Bodies

   As described in RFC 3265 [7], 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.

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.

3.6  Notifier Generation of NOTIFY Requests

   Notifications MUST 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.




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   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
   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 not 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



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   package.


















































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4.  Conference Document

4.1  Format

   Conference information is an XML document that MUST be well-formed
   and SHOULD be valid.  It MUST be based on Extensible Markup Language
   (XML) 1.0 and MUST be encoded using UTF-8 [11].

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 [4] and
   extended by RFC 3688 [12].  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
   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 optional 'version' attribute MUST be included in the root
   <conference-info> element.

4.4  State and Partial Notifications

   All sub-elements in the <conference-info> hierarchal XML structure
   can be classified in two groups: those that carry relatively small
   amount of data and those that can potentially carry a lot of data.
   During partial notifications, the light elements are updated as
   atomic pieces of data.  On the other hand, elements that can carry a
   substantial amount of data have the general 'state' attribute
   attached to them.  That is in order to support partial notifications
   for their content.

   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



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   "partial", the state of its children MAY be either "partial", "full",
   or "deleted".

4.5  Element Keys

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

   In a partial notification event it must be possible to uniquely
   identify each sub-element among others of the same type under a
   common parent element.  In order to achieve this property, all
   sub-elements, with possible multiple appearances under a common
   parent (which has the attribute 'state') have keys defined to them.

   Below is the list of the elements with their keys as defined by this
   specification:

   o  Elements <conference-info>, <user>, and <endpoint> use as the key
      'entity'
   o  Element <media> uses as the key 'id'
   o  Sub-element <entry> of uris-type contained in elements
      <conf-uris>, <service-uris>, and  <recording> uses as the key
      <uri>
   o  Elements <available-media> and <active-media> of
      conference-medias-type use as the key <proto>
   o  Elements <maximum-user-count> and <user-count> of count-type use
      as the key <role>
   o  Element <role> of user-roles-type uses as the key <entry>
   o  Sub-element <entry> of conference-type contained in element
      <sidebars-by-val> uses as the key 'entity'
   o  Elements <associated-uris> and <sidebars-by-ref> of uris-type use
      as the key <uri>

4.6  Constructing Coherent State Procedure

   A Conference package subscriber MUST initialize the 'version'
   attribute from the <conference-info> element with the value in the
   first document received.

   The conference package subscriber locally maintains a local element
   for each element in the schema and a table for each element with
   key(s) in the schema and indexed by these key(s).

   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 less than the
   local version, the document is discarded without processing.  If the



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   value in the document is higher than the local version number, the
   local version number is set to the value in the new document and the
   document is processed.  If the value in the received document is more
   than one higher than the previous local version number and the
   document contained a partial state, the subscriber SHOULD generate a
   refresh request to trigger a full state notification.

   Further processing of the conference information depends on the state
   contained in the received conference document and indicated by the
   value of the 'state' attribute in the <conference-info> element.  If
   it contains "full" state, the whole local content is flushed and
   repopulated from the document.  If it contains "deleted" state, it
   means that the conference ceased to exist and the subscriber SHOULD
   terminate the subscription by sending the SUBSCRIBE with Expires = 0.

   If the document contains "partial" state, the document is used to
   update the local content as described below.

   Starting from outer elements in the received document,

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

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

   3.  Otherwise, if the parent 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 2.2.

   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.






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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:


   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.
      Versions start at 0 and increment by one for each new document
      sent to a subscriber.  Versions are scoped within a subscription.
      Versions are represented using a 32 bit integer.

   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.





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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.

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 the 'state' attribute which can contain the values
   "full", "partial", or "deleted".

   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.




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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.

   Examples of such URIs include h323: [15] and tel: [14] 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 only currently defined
   <purpose> value is "web-page" which indicates a web page that
   contains additional information about the conference.  Future
   extensions to this schema may define new values and establish an IANA
   registry for the new values.

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

   This element is used to specify the maximum number of users permitted
   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.

5.2.8  available-media of conference-medias-type

   This element contains information about the media types available in
   the conference.  The <entry> sub-element MUST contain one of the
   values registered for "proto" of SDP [3] and its later revision(s).

5.3  host-type

   This type defines the 'state' attribute which can contain the values
   "full", "partial", or "deleted".

   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



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   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 the 'state' attribute which can contain the values
   "full", "partial", or "deleted".

   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.
   For example, a conference can be scheduled for a certain start time
   and its conference URI reserved and published.  Still, the conference
   will not be "active" till its actual start time.

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).

5.4.4  recording of uris-type

   The <entry> sub-element contains URIs related to the recording of the
   conference.





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5.4.5  active-media of conference-medias-type

   This element contains information about the media types currently
   active in the conference, which is a subset of those listed in the
   <available-media> element.

5.5  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
      unique.  The guidelines for generating anonymous URIs in RFC 3323
      [8] 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.

5.5.1  display-text of string type

   This element contains the display text for the user.

5.5.2  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.

5.5.3  roles of user-roles-type

   This element contains the roles of the user.




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5.5.4  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.

5.5.5  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 [16], 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 [17] of the
   cascaded foci and correlating the relevant information.

5.5.6  endpoint of endpoint-type

   This element contains information about an endpoint of the user.  The
   element of the endpoint-type can have unbounded number of appearance
   in the user-type for each endpoint of the user participating in the
   conference.  In a case when authentication is performed per endpoint
   (rather than per user) in a system, a focus can be not aware of the
   logical association among endpoints being used by the same user.  In
   this case the focus MAY present the endpoints as belonging to
   separate users in the conference schema.

   In a different case, due to privacy concerns for a user, the focus
   may want to shield the information about multiple endpoints from the
   recipients of the Conference document.  To do so the focus MAY
   aggregate the multiple endpoint information into a single endpoint
   element under this user.

5.6  endpoint-type

   This type defines the following attributes:

   entity: The attribute contains the endpoint URI for the user in the
      conference.  In SIP terms, this is the Contact URI or GRUU.  The
      'entity' attribute MUST be unique in the endpoint element list
      because it is used as the key in partial notifications about
      users' endpoints.  An endpoint belonging to an anonymous
      participant in a conference SHOULD be represented by an anonymous
      URI generated by the focus.  For multiple anonymous endpoints, the
      focus must ensure that each anonymous URI is unique.  The
      guidelines for generating anonymous URIs in RFC 3323 [8] should be



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      followed.

   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.

5.6.1  display-text of string type

   This element contains the display text for the endpoint.

5.6.2  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.

   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.

5.6.3  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



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      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 mostly active media.

   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 statuss (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.

5.6.4  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 participantÆs UA acts as a conference
      focus.





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5.6.5  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.

   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.

5.6.6  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 without success because was rejected by the focus
      according to local policy decisions.

   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.

5.6.7  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.

   reason: This element contains the reason the endpoint departed the
      conference.  When known, it is RECOMMENDED to include the numeric
      reason followed by the descriptive text as conveyed/reported by
      the call signaling.







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

5.6.8  media of media-type

   This element contains information about a media stream of this
   endpoint.  The element of the media-type can have unbounded number of
   appearance in the endpoint-type for each media stream of the
   endpoint.  Note that it is possible that media streams listed under a
   common endpoint MAY be established by separate signaling means and
   consequently belong to different signaling "calls".

5.7  media-type

   This type defines the following attributes:

   id: The attribute is a unique identifier of a media stream on a per
      endpoint basis.  This attribute is used as a key to identify media
      streams which may be added and deleted on a dynamic basis during
      the conference.  If the SDP "mid" (as defined in Grouping of Media
      Lines in the SDP [9]) is used for establishing the media stream,
      the 'id' SHOULD contain the same "mid" value, otherwise the
      notification service MUST generate an 'id' value which is unique
      in the endpoint context.

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

5.7.2  proto 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 "proto" of
   SDP [3] and its later revision(s).

5.7.3  src-id of string type

   The <src-id> element, if applicable, carries the information about
   the actual source of the media.  For example, for the RTP/RTCP [10]



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   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 [10],
   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)."

5.7.4  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
   defined in [19].

5.7.5  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".

5.7.6  call of call-type

   The <call> element is a general container for providing call
   signaling detailed information.  Note that privacy policies MUST be
   consulted before revealing this information to third-party
   participants.

   Specifically, 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> element can be expanded to include other call
   signaling protocol identifiers.








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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
   -->
   <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>



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   </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-medias-type" minOccurs="0"/>
        <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>

   <!--
      HOST TYPE
   -->
   <xs:complexType name="host-type">

      <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:attribute name="state" type="state-type" use="optional" default="full"/>
      <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"/>



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        <xs:element name="recording" type="uris-type" minOccurs="0"/>
        <xs:element name="active-media" type="conference-medias-type" minOccurs="0"/>
        <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>

   <!--
      CONFERENCE MEDIAS TYPE
   -->
   <xs:complexType name="conference-medias-type">

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

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

   </xs:complexType>

   <!--
      CONFERENCE MEDIA TYPE
   -->
   <xs:complexType name="conference-media-type">
      <xs:sequence>
        <xs:element name="proto" type="xs:string"/>
        <xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>

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

   <!--
      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>

   <!--



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

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

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

   <!--
      KEWORDS TYPE
   -->
   <xs:simpleType name="keywords-type">
          <xs:list itemType="xs:string"/>
   </xs:simpleType>

   <!--



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

   <!--
      ENDPOINT TYPE
   -->
   <xs:complexType name="endpoint-type">
      <xs:sequence>



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        <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: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>

   <!--
      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
   -->
   <xs:simpleType name="disconnection-type">



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          <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>

   <!--
      MEDIA TYPE
   -->
   <xs:complexType name="media-type">
      <xs:sequence>
        <xs:element name="display-text" type="xs:string" minOccurs="0"/>
        <xs:element name="proto" type="xs:string" minOccurs="0"/>
        <xs:element name="src-id" type="xs:string" minOccurs="0"/>
        <xs:element name="label" type="xs:string" minOccurs="0"/>
        <xs:element name="status" type="media-status-type" minOccurs="0"/>
        <xs:element name="call" type="call-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:attribute name="state" type="state-type" use="optional" default="full"/>
      <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"/>



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                <xs:enumeration value="inactive"/>
        </xs:restriction>
   </xs:simpleType>

   <!--
      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>

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

   <!--
      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</role>
                        <count>33</count>
                </entry>
        </user-count>
        <active-media>
                <entry>
                        <proto>audio</proto>
                </entry>
        </active-media>
      </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">



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                                <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>
                                        <by>sip:mike@example.com</by>
                                </disconnection-info>
                        <!--
                                MEDIA
                        -->
                        <media id="1">
                                <display-text>main audio</display-text>
                                <proto>audio</proto>
                                <src-id>432424</src-id>
                                <label>34567</label>
                                <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">
                        <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>
                                <proto>audio</proto>
                                <src-id>534232</src-id>
                                <label>34564</label>
                                <status>sendrecv</status>
                        </media>
          </endpoint>
          </user>



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      </users>

   </conference-info>


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>
                        </entry>
                        <entry>
                                <uri>h323:conf545@h323.example.com</uri>
                        </entry>
                </conf-uris>
                <service-uris>
                        <entry>
                                <uri>http://sharepoint/salesgroup/</uri>
                                <purpose>web-page</purpose>
                        </entry>
                </service-uris>
                <maximum-user-count>
                        <entry>
                                <role>any</role>
                                <count>52</count>
                        </entry>
                        <entry>



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                                <role>participant</role>
                                <count>50</count>
                        </entry>
                </maximum-user-count>
                <available-media>
                        <entry>
                                <proto>audio</proto>
                        </entry>
                        <entry>
                                <proto>video</proto>
                        </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</role>
                                <count>33</count>
                        </entry>
                        <entry>
                                <role>participant</role>
                                <count>32</count>
                        </entry>
                </user-count>
                <active>true</active>
                <locked>false</locked>

                <recording>
                        <entry>
        <uri>http://quicktime.streaming.com/54634/recording.mov</uri>
                                <display-text>Quicktime</display-text>
                        </entry>
                        <entry>



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        <uri>http://real.streaming.com/54634/recording.ram</uri>
                        </entry>
                </recording>

                <active-media>
                        <entry>
                                <proto>audio</proto>
                        </entry>
                </active-media>
        </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>



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

                        <!--
                                MEDIA
                        -->
                        <media id="1" state="full">
                                <display-text>main audio</display-text>
                                <proto>audio</proto>
                                <src-id>432424</src-id>
                                <label>34567</label>
                                <status>sendrecv</status>
                                <call>
                                        <sip>
                                           <display-text>full info</display-text>
                                           <call-id>hsjh8980vhsb78</call-id>
                                           <from-tag>vav738dvbs</from-tag>
                                           <to-tag>8954jgjg8432</to-tag>
                                        </sip>
                                </call>
          </media>
          </endpoint>
          </user>
      </users>

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



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

   </conference-info>












































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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 participants 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 [8].  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 5.5
   of this document MUST be followed.






























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9.  IANA Considerations

   This document registers a SIP event package, a new MIME type,
   application/conference-info+xml, a new XML namespace, and a new XML
   schema.

9.1  conference Event Package Registration

   This specification registers an event package, based on the
   registration procedures defined in RFC 3265 [7].  The following is
   the information required for such a registration:
   Package Name: conference
   Package or Template-Package: This is a package.
   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 [5].
   Encoding considerations: Same as encoding considerations of
      application/xml as specified in RFC 3023 [5].
   Security considerations: See Section 10 of RFC 3023 [5] 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 [12].






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   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:



   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 [12].
      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.















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10.  Acknowledgements

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














































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11.  References

11.1  Normative References

   [1]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
         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]   Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
         August 1999.

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

   [6]   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.

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

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

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

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

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

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

11.2  Informative References

   [13]  Schulzrinne, H., Rao, A. and R. Lanphier, "Real Time Streaming
         Protocol (RTSP)", RFC 2326, April 1998.

   [14]  Vaha-Sipila, A., "URLs for Telephone Calls", RFC 2806, April



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         2000.

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

   [16]  Rosenberg, J., "A Framework for Conferencing with the Session
         Initiation Protocol",
         draft-ietf-sipping-conferencing-framework-03 (work in
         progress), October 2004.

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

   [18]  Rosenberg, J., "Obtaining and Using Globally Routable User
         Agent (UA) URIs (GRUU) in the  Session Initiation Protocol
         (SIP)", draft-ietf-sip-gruu-02 (work in progress), July 2004.

   [19]  Levin, O. and G. Camarillo, "The SDP (Session Description
         Protocol) Label Attribute",
         draft-ietf-mmusic-sdp-media-label-00 (work in progress),
         September 2004.


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


   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




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

   EMail: oritl@microsoft.com












































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Intellectual Property Statement

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
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   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at
   ietf-ipr@ietf.org.


Disclaimer of Validity

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM 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.


Copyright Statement

   Copyright (C) The Internet Society (2004).  This document is subject
   to the rights, licenses and restrictions contained in BCP 78, and
   except as set forth therein, the authors retain all their rights.


Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.




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