SIPPING                                                     J. Rosenberg
Internet-Draft                                               dynamicsoft                                             Cisco Systems
Expires: April 25, May 28, 2005                                     H. Schulzrinne
                                                     Columbia University
                                                           O. Levin, Ed.
                                                   Microsoft Corporation
                                                        October 25,
                                                       November 27, 2004

    A Session Initiation Protocol (SIP) Event Package for Conference
                                 State
                draft-ietf-sipping-conference-package-06
                draft-ietf-sipping-conference-package-07

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   This document is an Internet-Draft and is subject to all provisions
   of section 3 of RFC 3667.  By submitting this Internet-Draft, each
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   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.

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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
   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  4
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  6  5
   3.  Conference Event Package . . . . . . . . . . . . . . . . . . .  7  6
     3.1   Event Package Name . . . . . . . . . . . . . . . . . . . .  7  6
     3.2   SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . .  7  6
     3.3   Subscription Duration  . . . . . . . . . . . . . . . . . .  7  6
     3.4   NOTIFY Bodies  . . . . . . . . . . . . . . . . . . . . . .  8  7
     3.5   Notifier Processing of SUBSCRIBE Requests  . . . . . . . .  8  7
     3.6   Notifier Generation of NOTIFY Requests . . . . . . . . . .  8  7
     3.7   Subscriber Processing of NOTIFY Requests . . . . . . . . .  9  8
     3.8   Handling of Forked Requests  . . . . . . . . . . . . . . .  9  8
     3.9   Rate of Notifications  . . . . . . . . . . . . . . . . . .  9  8
     3.10  State Agents . . . . . . . . . . . . . . . . . . . . . . .  9  8
   4.  Conference Data Model Document  . . . . . . . . . . . . . . . . . . . . 11
   5.  Constructing Coherent State . 10
     4.1   Format . . . . . . . . . . . . . . . . 12
   6.  Conference Data . . . . . . . . . . 10
     4.2   Namespace  . . . . . . . . . . . . . 14
     6.1   Conference Information . . . . . . . . . . . 10
     4.3   Versioning . . . . . . . 14
       6.1.1   Conference Type . . . . . . . . . . . . . . . . . 10
     4.4   State and Partial Notifications  . . 14
         6.1.1.1   conference-description of
                   conference-description-type . . . . . . . . . . . 14
         6.1.1.2   host-info of host-type 10
     4.5   Element Keys . . . . . . . . . . . . . . 14
         6.1.1.3   conference-state of conference-state-type . . . . 15
         6.1.1.4   user of user-type . . . . . 11
     4.6   Constructing Coherent State Procedure  . . . . . . . . . . 11
   5.  Conference Data  . 15
         6.1.1.5   sidebars-by-ref of uris-type . . . . . . . . . . . 15
         6.1.1.6   sidebar-by-val of conference-type . . . . . . . . 15
       6.1.2   Conference Description Type . . . 13
     5.1   conference-type  . . . . . . . . . . 15
         6.1.2.1   display-text of string type . . . . . . . . . . . 15
         6.1.2.2   subject 13
       5.1.1   conference-description of string type .
               conference-description-type  . . . . . . . . . . . . . 15
         6.1.2.3   free-text 13
       5.1.2   host-info of string type host-type . . . . . . . . . . . . . . 15
         6.1.2.4   keywords of keywords-type . . 13
       5.1.3   conference-state of conference-state-type  . . . . . . 14
       5.1.4   users of users-type  . . . . 16
         6.1.2.5   web-page of anyURI type . . . . . . . . . . . . . 16
         6.1.2.6   conf-uris 14
       5.1.5   sidebars-by-ref of uris-type . . . . . . . . . . . . . . 16
         6.1.2.7   service-uris 14
       5.1.6   sidebar-by-val of uris-type  . conference-type  . . . . . . . . . . 14
     5.2   conference-description-type  . 16
         6.1.2.8   maximum-user-count of user-count-type . . . . . . 16
         6.1.2.9   available-media of conference-medias-type . . . . 16
       6.1.3   Host Type . . . . 14
       5.2.1   display-text of string type  . . . . . . . . . . . . . 14
       5.2.2   subject of string type . . . . . 16
         6.1.3.1   display-text of string type . . . . . . . . . . . 16
         6.1.3.2   web-page 14
       5.2.3   free-text of anyURI string type . . . . . . . . . . . . . 17
         6.1.3.3   uris of uris-type . . 14
       5.2.4   keywords of keywords-type  . . . . . . . . . . . . . . 17
       6.1.4   Conference State Type 14
       5.2.5   conf-uris of uris-type . . . . . . . . . . . . . . . . 17
         6.1.4.1   user-count 15
       5.2.6   service-uris of user-count-type uris-type  . . . . . . . . . . 17
         6.1.4.2   security-level . . . . 15
       5.2.7   maximum-user-count of security-level-type user-count-type  . . . . . . 17
         6.1.4.3   active . . 15
       5.2.8   available-media of Boolean type conference-medias-type  . . . . . . 15
     5.3   host-type  . . . . . . . . 17
         6.1.4.4   locked of Boolean type . . . . . . . . . . . . . . 17
         6.1.4.5   recording of uris-type . . 15
       5.3.1   display-text of string type  . . . . . . . . . . . . . 17
         6.1.4.6   active-media 15
       5.3.2   web-page of conference-medias-type anyURI type  . . . . . . 18
       6.1.5   User Type . . . . . . . . . 16
       5.3.3   uris of uris-type  . . . . . . . . . . . . . 18
         6.1.5.1   display-text of string type . . . . . 16
     5.4   conference-state-type  . . . . . . 18
         6.1.5.2   associated-aors of anyURI type . . . . . . . . . . 18
         6.1.5.3   roles of user-roles-type . . 16
       5.4.1   user-count of user-count-type  . . . . . . . . . . . 18
         6.1.5.4   language of language . 16
       5.4.2   active of Boolean type . . . . . . . . . . . . 19
         6.1.5.5   cascaded-focus . . . . 16
       5.4.3   locked of anyURI Boolean type . . . . . . . . . . 19
         6.1.5.6   endpoint of endpoint-type  . . . . . . . 16
       5.4.4   recording of uris-type . . . . . 19
       6.1.6   Endpoint Type . . . . . . . . . . . 16
       5.4.5   active-media of conference-medias-type . . . . . . . . 17
     5.5   user-type  . 19
         6.1.6.1   display-text of string type . . . . . . . . . . . 20
         6.1.6.2   referred of execution-type . . . . . . . . . . . . 20
         6.1.6.3   state 17
       5.5.1   display-text of endpoint-state-type string type  . . . . . . . . . . . 20
         6.1.6.4   joining-method of joining-type . . 17
       5.5.2   associated-aors of anyURI type . . . . . . . . 21
         6.1.6.5   joining-info of execution-type . . . . 17
       5.5.3   roles of user-roles-type . . . . . . 21
         6.1.6.6   disconnection-method of disconnection-type . . . . 22
         6.1.6.7   disconnection-info of disconnection-type . . . . . 22
         6.1.6.8   whispering-to 17
       5.5.4   language of uris-type language type  . . . . . . . . . . . . 22
         6.1.6.9   media . . 18
       5.5.5   cascaded-focus of media-type anyURI type  . . . . . . . . . . . . 18
       5.5.6   endpoint of endpoint-type  . . . 22
       6.1.7   Media Type . . . . . . . . . . . 18
     5.6   endpoint-type  . . . . . . . . . . . 23
         6.1.7.1   display-text of string type . . . . . . . . . . . 23
         6.1.7.2   proto 18
       5.6.1   display-text of string type  . . . . . . . . . . . . . . . 23
         6.1.7.3   ssrc 19
       5.6.2   referred of string type  . execution-type . . . . . . . . . . . . . . 23
         6.1.7.4   label 19
       5.6.3   status of string type endpoint-status-type . . . . . . . . . . . . . . . 24
         6.1.7.5   state 19
       5.6.4   joining-method of media-state-type joining-type . . . . . . . . . . . . 24
         6.1.7.6   snd-status 20
       5.6.5   joining-info of media-state-type execution-type . . . . . . . . . . 24
         6.1.7.7   rcv-status state of media-state-type . . 21
       5.6.6   disconnection-method of disconnection-type . . . . . 24
         6.1.7.8   call of call-type . 21
       5.6.7   disconnection-info of execution-type . . . . . . . . . 21
       5.6.8   media of media-type  . . . . . . 24
   7.  Schema . . . . . . . . . . . 22
     5.7   media-type . . . . . . . . . . . . . . . . . 25
   8.  Examples . . . . . . . 22
       5.7.1   display-text of string type  . . . . . . . . . . . . . 22
       5.7.2   proto of string type . . . . . . . 33
     8.1   Basic Example . . . . . . . . . . 22
       5.7.3   src-id of string type  . . . . . . . . . . . . 33
     8.2   Rich Example . . . . 22
       5.7.4   label of string type . . . . . . . . . . . . . . . . . 23
       5.7.5   status of media-status-type  . . 35
   9.  Security Considerations . . . . . . . . . . . 23
       5.7.6   call of call-type  . . . . . . . . 40
   10.   IANA Considerations . . . . . . . . . . 23
   6.  XML Schema . . . . . . . . . . 41
     10.1  conference Event Package Registration . . . . . . . . . . 41
     10.2  application/conference-info+xml MIME Registration . . . . 41
     10.3  URN Sub-Namespace Registration for
           urn:ietf:params:xml:ns:conference-info . . 24
   7.  Examples . . . . . . . . 41
     10.4  XML Schema Registration . . . . . . . . . . . . . . . . . 42
   11.   Acknowledgements . . 32
     7.1   Basic Example  . . . . . . . . . . . . . . . . . . . . 43
   12.   Changes History . . 32
     7.2   Rich Example . . . . . . . . . . . . . . . . . . . . 44
     12.1  Changes since -05 . . . 34
   8.  Security Considerations  . . . . . . . . . . . . . . . . . 44
     12.2  Changes since -04 . . 39
   9.  IANA Considerations  . . . . . . . . . . . . . . . . . . 44
     12.3  Changes since -03 . . . 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 . . . 44
     12.4  Changes since -02 . . . . . . . 40
     9.4   XML Schema Registration  . . . . . . . . . . . . . 44
     12.5  Changes since -01 . . . . 41
   10.   Acknowledgements . . . . . . . . . . . . . . . . . . . . . 45
   13. . 42
   11.   References . . . . . . . . . . . . . . . . . . . . . . . . . 46
   13.1 43
   11.1  Normative References . . . . . . . . . . . . . . . . . . . . 46
   13.2 43
   11.2  Informative References . . . . . . . . . . . . . . . . . . . 46 43
       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 47 44
       Intellectual Property and Copyright Statements . . . . . . . . 49 46

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 [15]. [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.

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 [2] [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 [15]. [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"
   <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
   [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 6. 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.

   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 5 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
   package.

4.  Conference Data Model Document

4.1  Format

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

4.2  Namespace

   This specification makes use of XML namespaces for identifying dialog
   conference information documents and document fragments.  The
   namespace URI for elements defined by this specification is a URN [3],
   [2], using the namespace identifier 'ietf' defined by [4] and
   extended by [1]. 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". <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" <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" '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" 'state' attribute of a child element in the document MUST adhere to
   its parent "state". 'state'.  It means that if the parent's "state" 'state' is "full",
   the state of its children MUST be "full".  If the parent's "state" 'state' is
   "partial", the state of its children MAY be either "partial", "full",
   or "deleted".

   For elements with

4.5  Element Keys

   In the optional "state" attribute, if context of this specification, the attribute element key is
   omitted from the notification set of
   mandatory attributes or sub-elements of the element.  The key value
   MUST be unique for the element, element among its siblings of the same type.

   In a partial notification event it means that must be possible to uniquely
   identify each sub-element among others of the
   reported element's state is "full".

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

5.  Constructing Coherent State

   A Conference package subscriber MUST initialize them.

   Below is the "version"
   attribute from list of the "conference-info" element elements with their keys as defined by this
   specification:

   o  Elements <conference-info>, <user>, and <endpoint> use as the value in key
      'entity'
   o  Element <media> uses as the
   first document received.

   The conference package subscriber locally maintains a local element
   for each element key 'id'
   o  Sub-element <entry> of uris-type contained in the schema elements
      <conf-uris>, <service-uris>, and a table for each element  <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 "version" value of the 'version' attribute in the new received
   document are compared.  If the value in the new document is one higher less than the
   local version number, the local version number is increased by one,
   and version, the document is processed. discarded without processing.  If the
   value in the document is more
   than one higher than the local version number, the
   local version number is set to the value in the new document, document and the
   document is
   processed, 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.  If the value in the document is
   less than the local version, the document is discarded without
   processing.

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

   If the document contains partial "partial" state, as indicated by the value of
   the "state" attribute in the "conference-info" element, 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" 'state'
   attribute included or the state attribute is set to "full", the
   element is replaced with the new information as a whole.

   3.2.1 If an element, which doesnĘt have key(s), is updated or created
   such that its content is empty, that element MAY be removed from the
   local content at any time.

   3.3 For each non-atomic element with the state attribute set to
   "partial", the algorithm is applied recursively starting from step 3.

6.

5.  Conference Data

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

   A conference information document begins with the root element tag
   "conference-info".

6.1  Conference Information

   A conference instance is defined as a top level element
   "conference-info"
   <conference-info> of a type "conference-type". conference-type.  Sections below describe the
   complex types composing the hierarchal
   "conference-type". conference-type.  The full XML
   schema is defined in Section 7.

6.1.1  Conference Type 6.

5.1  conference-type

   This type has defines the following attributes:

   version: This mandatory attribute allows the recipient of conference
      information documents to properly order them.  Versions start at 0
      and increment by one for each new document sent to a subscriber.
      Versions are scoped within a subscription.  Versions MUST be
      represented using a 32 bit integer.

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

   state: This mandatory 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 5. 4.
   version: This type 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 optional
   sub-elements: <conference-description>, <conference-state>, and
   <users>.

   The child elements:

6.1.1.1 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.

6.1.1.2

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.

6.1.1.3

5.1.3  conference-state of conference-state-type

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

6.1.1.4  user conference.

5.1.4  users of user-type users-type

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

6.1.1.5

5.1.5  sidebars-by-ref of uris-type

   This element provides a pointer 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 conference package subscription.

6.1.1.6

5.1.6  sidebar-by-val of conference-type

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

6.1.2  Conference Description Type

5.2  conference-description-type

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

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

6.1.2.1

5.2.1  display-text of string type

   This element contains text information about description of the conference.

6.1.2.2

5.2.2  subject of string type

   This element contains information about the subject of a the conference.

6.1.2.3

5.2.3  free-text of string type

   This element contains free form text about the conference.

6.1.2.4

5.2.4  keywords of keywords-type

   This element contains a list of keywords which describe the
   conference topic.

6.1.2.5  web-page of anyURI type

   This element contains a URI of a web page words that contains information
   related can be used by automatic
   search engines to better classify the conference.

6.1.2.6

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 URIs URI that this
   conference can be accessed by.  Examples  The value of such URIs
   include h323: [14] and tel: [13] URIs.

6.1.2.7  service-uris 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 service-related URIs.  These URIs can URI to be used in order to manipulate access different services available
   for the conference policies or state, 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 example.

6.1.2.8 the new values.

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

   This element contains a count of is used to specify the maximum number of users permitted
   in the conference.  The count can number SHOULD be specified provided for all
   participants in total (using by populating the <role> sub-element with value "any") or
   count the
   "any".  Additionally counters for users by their with certain roles in the conference.

6.1.2.9
   conference MAY be separately provided.

5.2.8  available-media of conference-medias-type

   This element contains information about the media types available in
   a
   the conference.  The "entry" <entry> sub-element MUST be a value contain one of the
   values registered for "proto" of SDP [12].

6.1.3  Host Type [3] and its later revision(s).

5.3  host-type

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

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

6.1.3.1

5.3.1  display-text of string type

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

6.1.3.2

5.3.2  web-page of anyURI type

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

6.1.3.3

5.3.3  uris of uris-type

   The "entity" <entity> sub-element contains additional URIs relating pointing to the
   user hosting the conference.

6.1.4  Conference State Type
   conference host.

5.4  conference-state-type

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

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

6.1.4.1

5.4.1  user-count of user-count-type

   This element contains a count of is used to specify the current number of users in the
   conference.  The count can number SHOULD be specified provided for all participants in
   total
   (using by populating the <role> sub-element with value "any") or count the "any".
   Additionally counters for users by their with certain roles in the conference.

6.1.4.2  security-level of security-level-type

   This element contains information about the conference security
   level.  The values can
   MAY be "none", "low", "medium", or "high".

6.1.4.3 separately provided.

5.4.2  active of Boolean type

   This element contains information about says whether the conference is currently active or not.

6.1.4.4
   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 "locked" means that the
   conference roster can not be added to (although participants may
   leave or be removed from the conference).

6.1.4.5

5.4.4  recording of uris-type

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

6.1.4.6

5.4.5  active-media of conference-medias-type

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

6.1.5  User Type

5.5  user-type

   This type has defines the following attributes:

   entity: The mandatory 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" '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 mandatory 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 optional child
   elements.

6.1.5.1

5.5.1  display-text of string type

   This element contains the display text for the user.

6.1.5.2

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.

6.1.5.3

5.5.3  roles of user-roles-type

   This element contains the roles of the user.

6.1.5.4

5.5.4  language of language type

   This element contains the language used by preference of the user.

6.1.5.5  cascaded-focus of anyURI type  This element contains a conference URI (different from
   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 [15], [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 [16] [17] of the
   cascaded foci and correlating the relevant information.

6.1.5.6

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 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.

6.1.6  Endpoint Type

5.6  endpoint-type

   This type has defines the following attributes:

   entity: The mandatory attribute contains the endpoint URI for the user in the
      conference.  In SIP terms, this is the Contact URI or GRUU.  The "entity"
      '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 participants, endpoints, the
      focus must ensure that each anonymous URI is unique.  The
      guidelines for generating anonymous URIs in RFC 3323 [8] should be
      followed.

   state: This mandatory 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 optional child
   elements.

6.1.6.1

5.6.1  display-text of string type

   This element contains the display text for the endpoint.

6.1.6.2

5.6.2  referred of execution-type

   This element contains the URI of 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).

6.1.6.3  state  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-state-type endpoint-status-type

   This element contains the state 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" <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's device). endpoint).

   Note that the defined transient states 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.

6.1.6.4

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 participant participantĘs UA acts as a conference
      focus.

6.1.6.5

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.

6.1.6.6

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.

6.1.6.7

5.6.7  disconnection-info of disconnection-type 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.

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

6.1.6.8  whispering-to of uris-type

   If an endpoint is participating in a whisper session with other
   entities, the URIs of these other entities MAY be contained in this
   element.

6.1.6.9

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".

6.1.7  Media Type

5.7  media-type

   This type has defines the following attributes:

   entity:

   id: The mandatory 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.  The value of this element
      SHOULD correspond to the "mid" value in  If the SDP document as "mid" (as defined in Grouping of Media
      Lines in the SDP [9]. [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 mandatory attribute indicates whether the element contains the
      whole media information ("full"), only the information that has
      changed since the previous document notification ("partial"), or that the
      media element has been deleted from the conference document
      ("deleted").

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

6.1.7.1

5.7.1  display-text of string type

   This element contains the display text for the media stream.

6.1.7.2

5.7.2  proto of string type

   This element contains the media type for the media stream.  The value
   of this element MUST be a value one of the values registered for "proto" of
   SDP [12].

6.1.7.3  ssrc [3] and its later revision(s).

5.7.3  src-id of string type

   The "ssrc" element <src-id> element, if applicable, carries the value information about
   the actual source of SSRC (defined in the media.  For example, for the RTP/RTCP
   [10]) as [10]
   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)."

6.1.7.4

5.7.4  label of string type

   The element "label" <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 in
   SDP [12] and
   defined in [19].

6.1.7.5  state

5.7.5  status of media-state-type media-status-type

   The element "state" contains <status> indicates the state status in both directions of the
   media stream and can
   have has the values "active", "inactive", "sendrecv", "sendonly", "recvonly",
   or "muted".

6.1.7.6  snd-status of media-state-type

   The element "state" contains the state of the sending media stream
   (from the perspective of the endpoint) "inactive" as defined in SDP [3] and can have its later revision(s).  Note
   that value specifies the values
   "active", "inactive", or "muted".

6.1.7.7  rcv-status state of media-state-type

   The element "state" contains direction from the state participant's point of the receiving media
   view.  For example, a muted participant's stream
   (from the perspective of the endpoint) and can will have the values
   "active", "inactive", or "muted".

6.1.7.8 value
   of "recvonly".

5.7.6  call of call-type

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

7. <display-text>, <call-id>, <to-tag>,
   <from-tag>.

   In future, the <call> element can be expanded to include other call
   signaling protocol identifiers.

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="user" type="user-type" minOccurs="0" maxOccurs="unbounded"/> name="users" type="users-type" minOccurs="0"/>
   	<xs:element name="sidebars-by-ref" type="uris-type" minOccurs="0"/>
   	<xs:element name="sidebar-by-val" type="conference-type" minOccurs="0" maxOccurs="unbounded"/>
                        <xs:element name="extended" type="extended-type" 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"/> use="optional" default="full"/>
      <xs:attribute name="version" type="xs:string" type="xs:unsignedInt" use="optional"/>
                <xs:anyAttribute/>
      <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="web-page" type="xs:anyURI" 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:element name="extended" type="extended-type"
   	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>

      <xs:attribute name="state" type="state-type" use="optional"/>
                <xs:anyAttribute/> 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:element name="extended" type="extended-type"
   	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>

      <xs:attribute name="state" type="state-type" use="optional"/>
                <xs:anyAttribute/> 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="security-level" type="security-level-type" minOccurs="0"/>
                        <xs:element name="active" type="xs:boolean" minOccurs="0"/>
   	<xs:element name="locked" type="xs:boolean" minOccurs="0"/>
   	<xs:element name="recording" type="uris-type" minOccurs="0"/>
   	<xs:element name="active-media" type="conference-medias-type" minOccurs="0"/>
                        <xs:element name="extended" type="extended-type"
   	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>

      <xs:attribute name="state" type="state-type" use="optional"/>
                <xs:anyAttribute/> 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"/>
                <xs:anyAttribute/> 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:element name="extended" type="extended-type"
   	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
                <xs:anyAttribute/>

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

   <!--
          CONFERENCE
      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"/>
                <xs:anyAttribute/> use="optional" default="full"/>
      <xs:anyAttribute namespace="##other"/>
   </xs:complexType>

   <!--
          CONFERENCE
      URI TYPE
   -->
   <xs:complexType name="uri-type">
      <xs:sequence>
   	<xs:element name="uri" type="xs:anyURI"/>
   	<xs:element name="label" 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:element name="extended" type="extended-type"
   	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
                <xs:anyAttribute/>

      <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"/>
                <xs:anyAttribute/> use="optional" default="full"/>
      <xs:anyAttribute namespace="##other"/>
   </xs:complexType>

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

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

   <!--
          SECURITY LEVEL TYPE
        -->
        <xs:simpleType name="security-level-type">
                <xs:restriction base="xs:string">
                        <xs:enumeration value="none"/>
                        <xs:enumeration value="low"/>
                        <xs:enumeration value="medium"/>
                        <xs:enumeration value="high"/>
                </xs:restriction>
        </xs:simpleType>
        <!--
      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:element name="extended" type="extended-type"
   	<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"/>
                <xs:anyAttribute/> 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="user-role-type" type="xs:string" maxOccurs="unbounded"/>
      </xs:sequence>

      <xs:attribute name="state" type="state-type" use="optional"/>
                <xs:anyAttribute/>
        </xs:complexType>
        <!--
          USER ROLE TYPE
        -->
        <xs:complexType name="user-role-type">
                <xs:choice>
                        <xs:element name="label" type="xs:string"/>
                </xs:choice>
                <xs:attribute name="conf-template" type="xs:string" use="optional"/> use="optional" default="full"/>
      <xs:anyAttribute namespace="##other"/>
   </xs:complexType>

   <!--
      ENDPOINT TYPE
   -->
   <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="state" type="endpoint-state-type" minOccurs="0"/>
                        <xs:element name="whispering-to" type="uris-type" 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="extended" type="extended-type"
   	<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"/>
                <xs:anyAttribute/> use="optional" default="full"/>
      <xs:anyAttribute namespace="##other"/>
   </xs:complexType>

   <!--
      ENDPOINT STATE STATUS TYPE
   -->
   <xs:simpleType name="endpoint-state-type"> 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">
          <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/>

      <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="ssrc" name="src-id" type="xs:string" minOccurs="0"/>
   	<xs:element name="label" type="xs:string" minOccurs="0"/>
   	<xs:element name="state" type="media-state-type" minOccurs="0"/>
                        <xs:element name="snd-status" type="media-state-type" minOccurs="0"/>
                        <xs:element name="rcv-status" type="media-state-type" name="status" type="media-status-type" minOccurs="0"/>
   	<xs:element name="call" type="call-type" minOccurs="0"/>
                        <xs:element name="extended" type="extended-type"
   	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>

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

   <!--
      MEDIA STATUS TYPE
   -->
   <xs:simpleType name="media-state-type"> name="media-status-type">
   	<xs:restriction base="xs:string">
   		<xs:enumeration value="active"/> value="recvonly"/>
   		<xs:enumeration value="inactive"/> value="sendonly"/>
   		<xs:enumeration value="sendrecv"/>
   		<xs:enumeration value="muted"/> 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:element name="extended" type="extended-type"
   	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
      </xs:choice>
                <xs:anyAttribute/>

      <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="dialog-id" name="call-id" type="xs:string"/>
   	<xs:element name="from-tag" type="xs:string"/>
   	<xs:element name="to-tag" type="xs:string"/>
                        <xs:element name="extended" type="extended-type"
   	<xs:any namespace="##other" processContents="lax" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
                <xs:anyAttribute/>

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

   <!--
          EXTENDED
      SIDEBARS BY VAL TYPE
   -->
   <xs:complexType name="extended-type"> name="sidebars-by-val-type">
      <xs:sequence>
                        <xs:any
   	<xs:element name="entry" type="conference-type" minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>

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

   </xs:schema>

8.

7.  Examples

8.1

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 target</subject> goals</subject>
   	<service-uris>
   		<entry>
                                <uri>http://salesgroup.example.com/conference-policies/sales-weekly-meeting.xml</uri>
                                <label>CPCP</label>
   			<uri> http://sharepoint/salesgroup/</uri>
   			<purpose>web-page</purpose>
   		</entry>
   	</service-uris>
      </conference-description>

   <!--
      CONFERENCE STATE
   -->
      <conference-state>
   	<user-count>
   		<entry>
                                <role>
                                        <label>any</label>
                                </role>
   			<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">
   				<display-text>Bob's Laptop</display-text>
                        <state>disconnected</state>
   				<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 entity="1"> id="1">
   				<display-text>main audio</display-text>
   				<proto>audio</proto>
                                <ssrc>432424</ssrc>
   				<src-id>432424</src-id>
   				<label>34567</label>
                                <state>active</state>
   				<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">
                        <state>connected</state>
   	 		<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 entity="1"> id="1">
   				<display-text>main audio</display-text>
    				<proto>audio</proto>
                                        <ssrc>534232</ssrc>
    				<src-id>534232</src-id>
    				<label>34564</label>
                                        <state>active</state>
    				<status>sendrecv</status>
    			</media>
          </endpoint>
          </user>
      </users>

   </conference-info>

8.2

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 URI 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 target</subject>
                <free-text>xyz</free-text> goals</subject>
   		<free-text>We will start strict on time</free-text>
   		<keywords>sales, meeting, weekly</keywords>
                <web-page>http://sharepoint/salesgroup/</web-page>
   		<conf-uris>
   			<entry>
   				<uri>tel:+18005671234</uri>
                                <label>TTI Bridge</label>
   				<display-text>TTI Bridge</display-text>
   			</entry>
   			<entry>
   				<uri>h323:conf545@h323.example.com</uri>
   			</entry>
   		</conf-uris>
   		<service-uris>
   			<entry>
                                <uri>http://salesgroup.example.com/conference-policies/sales-weekly-meeting.xml</uri>
                                <label>CPCP</label>
   				<uri>http://sharepoint/salesgroup/</uri>
   				<purpose>web-page</purpose>
   			</entry>
   		</service-uris>
   		<maximum-user-count>
   			<entry>
                                <role>
                                        <label>any</label>
                                </role>
   				<role>any</role>
   				<count>52</count>
   			</entry>
   			<entry>
                                <role conf-template="Basic">
                                        <label>participant</label>
                                </role>
   				<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>
                                        <label>any</label>
                                </role>
   				<role>any</role>
   				<count>33</count>
   			</entry>
   			<entry>
                                <role conf-template="Basic">
                                        <label>participant</label>
                                </role>
   				<role>participant</role>
   				<count>32</count>
   			</entry>
   		</user-count>
                <security-level>medium</security-level>
   		<active>true</active>
   		<locked>false</locked>

   		<recording>
   			<entry>
   	<uri>http://quicktime.streaming.com/54634/recording.mov</uri>
                                <label>Quicktime</label>
   				<display-text>Quicktime</display-text>
   			</entry>
   			<entry>
   	<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" state="full"> entity="sip:bob@example.com">
   		<display-text>Bob Hoskins</display-text>
   		<associated-aors>
   			<entry>
   				<uri>mailto:bob@example.com</uri>
                                <label>email</label>
   				<display-text>email</display-text>
   			</entry>
   		</associated-aors>
   		<roles>
                        <entry>
                                <label>participant</label>
                        </entry>
   			<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>
                        <state>disconnecting</state>
                        <whispering-to>
                        <entry>
                                <uri>sip:rob@example.com</uri>
                        </entry>
                        <entry>
                                <uri>sip:helen@example.com</uri>
                        </entry>
                        </whispering-to>
   			<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>
   			</disconnection-info>

   			<!--
   	  			MEDIA
   			-->
   			<media entity="1" id="1" state="full">
   				<display-text>main audio</display-text>
   				<proto>audio</proto>
                                <ssrc>432424</ssrc>
   				<src-id>432424</src-id>
   				<label>34567</label>
                                <state>active</state>
   				<status>sendrecv</status>
   				<call>
   					<sip>
   					   <display-text>full info</display-text>
                                                <dialog-id>hsjh8980vhsb78</dialog-id>
   					   <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>
                                        <label>sidebar
   		<display-text>sidebar with Carol</label> Carol</display-text>
   	</entry>
   	<entry>
   		<uri>sips:conf233@example.com; grid=21</uri>
                                        <label>private
   		<display-text>private sidebar with Peter</label> Peter</display-text>
   	</entry>
      </sidebars-by-ref>

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

   </conference-info>

9.

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 "User
   Element" Section 5.5
   of this document MUST be followed.

10.

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.

10.1

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.

10.2

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 9 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.

10.3

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
   [1].
   RFC 3688 [12].

   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

10.4  XML Schema Registration

   This specification registers a schema, as per the guidelines in in
   [1].
      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 7.

11.  Acknowledgements

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

12.  Changes History

12.1  Changes since -05
   o  General schema clean-up.
   o  Definition of common types being used by multiple elements.
   o  Introduction of an "endpoint" element as a part of hierarchy:
      user/endpoint/media.

12.2  Changes since -04
   o
   o  "Sidebar-type" has been removed.  "Sidebar" conference element is
      defined using the general "conference-type".
   o  "Recording" conference attribute has been replaced with
      "recording" and "streaming" elements within "conference-type".
      New "recording-type" and "streaming-type" have been introduced.
   o  Attribute "state" has been added to "user-type".
   o  Element "media-stream" within "user-type" has been renamed to
      "media".
   o  Element "role" within "user-type" has been introduced.
   o  The following statuses have been added to "user-status-type":
      blocked, pending, calling, ringing, dialing-in, disconnecting,
      removed.
   o  User status "muted-by-focus" has been renamed to
      "muted-via-focus".
   o  Attributes "id" and "state" have been added to "media-type".
   o  Elements "status", "snd-status" and "rcv-status" have been added
      to "media-type".
   o  Element "dialog-id" has been renamed to "instance".
   o  "Constructing Coherent State" section has been updated to include
      user and media partial notifications.

12.3  Changes since -03
   o  "Constructing Coherent State" section has been updated.
   o  In order to support partial notifications, two placeholders
      "conference-ids" and "policy-ids" (for "conf-uri" and "policy-uri"
      elements, correspondingly) are created.
   o  Discussion and security considerations regarding anonymous
      participation have been added.
   o  Optional elements "dialog-uri", "info" and "label" per media
      stream are added.

12.4  Changes since -02
   o  State "muted-by-focus" is added to user's status.
   o  Optional conference attribute "recording" is added.
   o  Policy URI placeholder (i.e.  element "policy-uri") is created.
   o  Example's syntax is corrected.
   o  Optional attribute "cascaded-focus" URI per user is added.

   o  Optional additional conference identifiers (i.e.  element
      "conf-uri") are added.
   o  In order to cover all possible cases, participant's status is
      expressed using three optional statuses: "status", "joining-mode"
      and "disconnection-reason".  That is instead <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 "activity-status",
      "history-status" and "is-on-dial-out-list".

12.5  Changes since -01
   o  Package parameters are removed.  Decision about performing
      "recursive" membership algorithm is perceived as published RFC]]]">RFCXXXX</a>.</p>
   </body>
   </html>
   END

9.4  XML Schema Registration

   This specification registers a focus local
      policy.
   o  General information (i.e.  pointers to additional available
      services) is removed. 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 defined XML schema can be extended in
      future to include those when XCON work matures.
   o  Dialog information is removed.  It can be obtained by direct
      subscription to a dialog package found as the sole content of a participant.
   o  Media stream information is aligned with SDP definitions (media
      and proto) Section 6.

10.  Acknowledgements

   The authors would like to thank Dan Petrie, Sean Olson, Alan
   Johnston, Rohan Mahy, Cullen Jennings, and SSRC attribute is added.
   o  Participant's status is expressed using two optional statuses:
      "activity" Miguel Garcia for their
   comments and "history".  Optional "is-on-a-dial-out-list"
      indication is added.
   o  Normative references to XCON work are removed.
   o  Optional sidebar rosters are added.

13. inputs.

11.  References

13.1

11.1  Normative References

   [1]   Mealling, M., "The IETF XML Registry",
         draft-mealling-iana-xmlns-registry-05 (work in progress), June
         2003.

   [2]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", BCP 14, RFC 2119, March 1997.

   [3]

   [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.

13.2

   [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

   [11]

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

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

   [13]

   [14]  Vaha-Sipila, A., "URLs for Telephone Calls", RFC 2806, April
         2000.

   [14]

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

   [15]

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

   [16]

   [17]  Rosenberg, J. and H. Schulzrinne, J., "An INVITE Inititiated Dialog Event Package for
         the Session Initiation  Protocol (SIP)",
         draft-ietf-sipping-dialog-package-04 (work in progress),
         February 2004.

   [17]  Koskelainen, P. and H. Khartabil, "Requirements for Conference
         Policy Control Protocol", draft-ietf-xcon-cpcp-reqs-04
         draft-ietf-sipping-dialog-package-05 (work in progress), August
         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
   dynamicsoft
   Cisco Systems
   600 Lanidex Plaza
   Parsippany, NJ  07054
   US

   Phone: +1 973 952-5000
   EMail: jdrosen@dynamicsoft.com 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
   Orit Levin (editor)
   Microsoft Corporation
   One Microsoft Way
   Redmond, WA  98052
   USA
   US

   EMail: oritl@microsoft.com

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