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Versions: (draft-barnes-xcon-ccmp) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 RFC 6503

XCON Working Group                                             M. Barnes
Internet-Draft                                                    Nortel
Intended status: Standards Track                              C. Boulton
Expires: August 21, 2010                                 NS-Technologies
                                                             S P. Romano
                                                    University of Napoli
                                                          H. Schulzrinne
                                                     Columbia University
                                                       February 17, 2010


             Centralized Conferencing Manipulation Protocol
                        draft-ietf-xcon-ccmp-06

Abstract

   The Centralized Conferencing Manipulation Protocol (CCMP) allows a
   XCON conferencing system client to create, retrieve, change and
   delete objects describing a centralized conference, being a mean to
   control basic and advanced conference features such as conference
   state and capabilities, participants and relative roles and details.
   The CCMP is a state-less, XML-based, client server protocol carrying
   in its request and response messages conference information in the
   form of XML documents and fragments conforming to the centralized
   conferencing data model schema.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
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   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on August 21, 2010.



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Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  XCON Conference Control System Architecture . . . . . . . . .   7
     4.1.  Conference Objects  . . . . . . . . . . . . . . . . . . .   8
     4.2.  Conference Users  . . . . . . . . . . . . . . . . . . . .   9
   5.  Protocol Overview . . . . . . . . . . . . . . . . . . . . . .  10
     5.1.  Protocol Operations . . . . . . . . . . . . . . . . . . .  10
     5.2.  Implementation Approach . . . . . . . . . . . . . . . . .  13
   6.  CCMP messages . . . . . . . . . . . . . . . . . . . . . . . .  14
     6.1.  CCMP Request Message Type . . . . . . . . . . . . . . . .  14
     6.2.  CCMP Response Message Type  . . . . . . . . . . . . . . .  16
     6.3.  Detailed messages . . . . . . . . . . . . . . . . . . . .  17
       6.3.1.  blueprintsRequest and blueprintsResponse  . . . . . .  20
       6.3.2.  confsRequest and confsResponse  . . . . . . . . . . .  22
       6.3.3.  blueprintRequest and blueprintResponse  . . . . . . .  23
       6.3.4.  confRequest and confResponse  . . . . . . . . . . . .  25
       6.3.5.  usersRequest and usersResponse  . . . . . . . . . . .  29
       6.3.6.  userRequest and userResponse  . . . . . . . . . . . .  32
       6.3.7.  sidebarsByValRequest and sidebarsByValResponse  . . .  36
       6.3.8.  sidebarByValRequest and sidebarByValResponse  . . . .  38
       6.3.9.  sidebarsByRefRequest and sidebarsByRefResponse  . . .  41
       6.3.10. sidebarByRefRequest and sidebarByRefResponse  . . . .  42
     6.4.  CCMP Response Codes . . . . . . . . . . . . . . . . . . .  45
   7.  A complete example of the CCMP in action  . . . . . . . . . .  49
     7.1.  Alice retrieves the available blueprints  . . . . . . . .  49
     7.2.  Alice gets detailed information about a specific
           blueprint . . . . . . . . . . . . . . . . . . . . . . . .  52
     7.3.  Alice creates a new conference through a cloning
           operation . . . . . . . . . . . . . . . . . . . . . . . .  54



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     7.4.  Alice updates conference information  . . . . . . . . . .  56
     7.5.  Alice inserts a list of users in the conference object  .  58
     7.6.  Alice joins the conference  . . . . . . . . . . . . . . .  60
     7.7.  Alice adds a new user to the conference . . . . . . . . .  62
   8.  Locating a Conference Control Server  . . . . . . . . . . . .  65
   9.  Managing Notifications  . . . . . . . . . . . . . . . . . . .  67
   10. HTTP Transport  . . . . . . . . . . . . . . . . . . . . . . .  68
   11. Security Considerations . . . . . . . . . . . . . . . . . . .  70
     11.1. Assuring that the Proper Conferencing Server has been
           contacted . . . . . . . . . . . . . . . . . . . . . . . .  71
     11.2. User Authentication and Authorization . . . . . . . . . .  71
     11.3. Security and Privacy of Identity  . . . . . . . . . . . .  72
   12. XML Schema  . . . . . . . . . . . . . . . . . . . . . . . . .  73
   13. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  87
     13.1. URN Sub-Namespace Registration  . . . . . . . . . . . . .  87
     13.2. XML Schema Registration . . . . . . . . . . . . . . . . .  87
     13.3. MIME Media Type Registration for 'application/ccmp+xml' .  88
     13.4. DNS Registrations . . . . . . . . . . . . . . . . . . . .  89
       13.4.1. Registration of a Conference Control Server
               Application Service Tag . . . . . . . . . . . . . . .  89
       13.4.2. Registration of a Conference Control Server
               Application Protocol Tag for CCMP . . . . . . . . . .  89
     13.5. CCMP Protocol Registry  . . . . . . . . . . . . . . . . .  90
       13.5.1. CCMP Message Types  . . . . . . . . . . . . . . . . .  90
       13.5.2. CCMP Response Codes . . . . . . . . . . . . . . . . .  91
   14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  94
   15. Changes since last Version  . . . . . . . . . . . . . . . . .  95
   16. References  . . . . . . . . . . . . . . . . . . . . . . . . .  97
     16.1. Normative References  . . . . . . . . . . . . . . . . . .  97
     16.2. Informative References  . . . . . . . . . . . . . . . . .  97
   Appendix A.  Appendix A: Other protocol models and transports
                considered for CCMP  . . . . . . . . . . . . . . . .  99
     A.1.  Using SOAP for the CCMP . . . . . . . . . . . . . . . . .  99
     A.2.  A RESTful approach for the CCMP . . . . . . . . . . . . . 100
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 101
















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1.  Introduction

   The Framework for Centralized Conferencing [RFC5239] (XCON Framework)
   defines a signaling-agnostic framework, naming conventions and
   logical entities required for building advanced conferencing systems.
   The XCON Framework introduces the conference object as a logical
   representation of a conference instance, representing the current
   state and capabilities of a conference.

   The Centralized Conferencing Manipulation Protocol (CCMP) defined in
   this document allows authenticated and authorized users to create,
   manipulate and delete conference objects.  Operations on conferences
   include adding and removing participants, changing their roles, as
   well as adding and removing media streams and associated end points.

   The CCMP implements the client-server model within the XCON
   Framework, with the Conference Control Client and Conference Control
   Server acting as client and server, respectively.  The CCMP uses HTTP
   [RFC2616] as the protocol to transfer requests and responses, which
   contain the domain-specific XML-encoded data objects defined in
   [I-D.ietf-xcon-common-data-model] Conference Information Data Model
   for Centralized Conferencing (XCON Data Model).

   Section 4 provides an overview of the Conference Control
   functionality of the XCON framework, together with a description of
   the main targets CCMP deals with, namely conference objects and
   conference users.  A general description of the operations associated
   with protocol messages is given in Section 5 together with
   implementation details.  A complete example of the operation of the
   CCMP, describing a typical call flow associated with conference
   creation and manipulation, is provided in Section 7.  Section 12
   provides the XML schema.



















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2.  Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].














































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3.  Terminology

   In additon to the terms defined in the Framework for Centralized
   Conferencing [RFC5239], this document uses the following terms and
   acronyms:

   XCON aware client:   An XCON conferencing system client which is able
      to issue CCMP requests.











































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4.  XCON Conference Control System Architecture

   CCMP supports the XCON framework .  Figure 1 depicts a subset of the
   "Conferencing System Logical Decomposition" architecture from the
   XCON framework document.  It illustrates the role that CCMP assumes
   within the overall centralized architecture.


   ........................................................
   .  Conferencing System                                 .
   .                                                      .
   .        +---------------------------------------+     .
   .        |   C O N F E R E N C E   O B J E C T   |     .
   .      +-+-------------------------------------+ |     .
   .      |   C O N F E R E N C E   O B J E C T   | |     .
   .    +-+-------------------------------------+ | |     .
   .    |   C O N F E R E N C E   O B J E C T   | | |     .
   .    |                                       | |-+     .
   .    |                                       |-+       .
   .    +---------------------------------------+         .
   .                        ^                             .
   .                        |                             .
   .                        v                             .
   .               +-------------------+                  .
   .               | Conference Control|                  .
   .               | Server            |                  .
   .               +-------------------+                  .
   .                        ^                             .
   .........................|..............................
                            |
                            |Centralized
                            |Conferencing
                            |Manipulation
                            |Protocol
                            |
   .........................|..............................
   .                        V                             .
   .                +----------------+                    .
   .                | Conference     |                    .
   .                | Control        |                    .
   .                | Client         |                    .
   .                +----------------+                    .
   .                                                      .
   .  Conferencing Client                                 .
   ........................................................


                  Figure 1: Conference Client Interaction



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   CCMP serves as the Conference Control Protocol, allowing the
   conference control client to interface with the conference object
   maintained by the conferencing system, as represented in Figure 1.
   Conference Control is one part of functionality for advanced
   conferencing supported by a conferencing client.  Other functions are
   discussed in the XCON framework and related documents.

   Conference object and conference users do represent key elements
   involved in Conference Control Protocol operations.  Their
   identifiers, respectively the conference XCON-URI and the
   conferencing client XCON-USERID, and their XML representations
   compliant with the XML Schema defined in the XCON data model are
   widely used for creating the CCMP requests and responses.  The main
   conference objects and users features envisioned by the XCON
   framework are briefly described in the following subsections.

4.1.  Conference Objects

   Conference objects feature a simple dynamic inheritance-and-override
   mechanism.  Conference objects are linked into a tree known as
   "cloning tree" (see Section 7.1 of [RFC5239]).  Each cloning tree
   node inherits attributes from its parent node.  The roots of these
   inheritance trees are conference templates also known as
   "blueprints".  Nodes in the inheritance tree can be active
   conferences or simply descriptions that do not currently have any
   resources associated with them (conference reservations).  An object
   can mark certain of its properties as unalterable, so that they
   cannot be overridden.  It is envisaged by the framework that a client
   MAY specify a parent object (a conference or blueprint) from which
   the conference to be created has to inherit values by the mean of the
   Conference Control Protocol.

   Conference objects are uniquely identified by the XCON-URI within the
   scope of the conferencing system.  Such identifier is introduced in
   the XCON framework and defined in the XCON common data model.

   Conference objects are comprehensively represented through XML
   documents compliant with the XML Schema defined in the XCON data
   model [I-D.ietf-xcon-common-data-model].  The root element of such
   documents is one of type "conference-type" called "<conference-info>"
   which encompasses other XML elements describing different conference
   features and users as well.  By the mean of CCMP, conferencing
   clients can use such XML structures to express their preferences in
   creation or update and conferencing server can convey conference
   information of such a form back to them.






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4.2.  Conference Users

   Each conference can have zero or more users.  All conference
   participants are users, but some users may have only administrative
   functions and do not contribute or receive media.  Users are added
   one user at a time to simplify error reporting.  When a conference is
   cloned from a parent object, users are inherited as well, so that it
   is easy to set up a conference that has the same set of participants
   or a common administrator.  The Conference Control Server creates
   individual users, assigning them a unique Conference User Identifier
   (XCON-USERID).  The XCON-USERID as identifier of each conferencing
   system client is introduced in the XCON framework and defined in the
   XCON common data model.  Each CCMP request, with an exception pointed
   out in Section 6.3.6 representing the case of a user at his first
   entrance in the system as a conference participant, MUST carry the
   XCON-USERID of the requestor in the proper "confUserID" parameter.

   The XCON-USERID acts as a pointer to the user's profile as a
   conference actor, e.g. her signalling URI and other XCON protocol
   URIs in general, her role (moderator, participant, observer, etc.),
   her display text, her joining information and so on.  A variety of
   elements defined in the common <conference-info> element as specified
   in the XCON data model are used to describe the users related to a
   conference, in the first place the <users> element, as well as each
   <user> element included in it.  For example, it is possible to
   determine how a specific user expects and is allowed to join a
   conference by looking at the <allowed-user-list> in <users>: each
   <target> element involved in such a list represents a user and shows
   a "method" attribute defining how the user is expected to join the
   conference, i.e. "dial-in" for users that are allowed to dial, "dial-
   out" for users that the conference focus will be trying to reach
   (with "dial-in" being the default mode).  If the conference is
   currently active, dial-out users are contacted immediately;
   otherwise, they are contacted at the start of the conference.  The
   CCMP, acting as the Conference Control Protocol, provides a means to
   manipulate these and other kinds of user-related features.

   As a consequence of an explicit user registration to a specific XCON
   conferencing system, conferencing clients are usually provided
   (besides the XCON-USERID) with log-in credentials (i.e. username and
   password).  Such credentials can be used to authenticate the XCON
   aware client issuing CCMP requests, in order to provide her with the
   right authorization information.  To this purpose, both username and
   password SHOULD be carried in a CCMP request as part of the "subject"
   parameter whenever a registered conferencing client wishes to contact
   a CCMP server.  The specific registration modality is out of the
   scope of the CCMP document.




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5.  Protocol Overview

   CCMP is a client-server, XML-based protocol, which has been
   specifically conceived to provide users with the necessary means for
   the creation, retrieval, modification and deletion of conference
   objects.  CCMP is also state-less, which means implementations can
   safely handle transactions independently from each other.
   Conference-related information is encapsulated into CCMP messages in
   the form of XML documents or XML document fragments compliant with
   the XCON data model representation.

   Section 5.1 specifies the basic operations that can create, retrieve,
   modify and delete conference-related information in a centralized
   conference.  The core set of objects manipulated in the CCMP protocol
   includes conference blueprints, the conference object, users, and
   sidebars.

   CCMP has been conceived as completely independent from underlying
   protocols, which means that there can be different ways to carry CCMP
   messages across the network, from a conferencing client to a
   conferencing server.  Nevertheless, it is recommended to use HTTP as
   a transport solution, including CCMP requests in HTTP POST messages
   and CCMP responses in HTTP 200 OK replies.  Implementation details
   are presented in Section 5.2

5.1.  Protocol Operations

   The main operations provided by CCMP belong in four general
   categories:

   create:  for the creation of a conference, a conference user, a
      sidebar, or a blueprint.

   retrieve:  to get information about the current state of either a
      conference object (be it an actual conference or a blueprint, or a
      sidebar) or a conference user.  A retrieve operation can also be
      used to obtain the XCON-URIs of the current conferences (active or
      registered) handled by the conferencing server and/or the
      available blueprints.

   update:  to modify the current features of a specified conference or
      conference user.

   delete:  to remove from the system a conference object or a
      conference user.

   Thus, the main targets of CCMP operations are:




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   o  conference objects associated with either active or registered
      conferences,

   o  conference objects associated with blueprints,

   o  conference objects associated with sidebars, both embedded in the
      main conference (i.e. <entry> elements in <sidebars-by-value>) and
      external to it (i.e. whose xcon-uris are included in the <entry>
      elements of <sidebars-by-ref>),

   o  <user> elements associated with conference users,

   o  the list of XCON-URIs related to conferences and blueprints
      available at the server, for which only retrieval operations are
      allowed.

   Each operation in the protocol model is atomic and either succeeds or
   fails as a whole.  The conference server MUST ensure that the
   operations are atomic in that the operation invoked by a specific
   conference client completes prior to another client's operation on
   the same conference object.  The details for this data locking
   functionality are out of scope for the CCMP protocol specification
   and are implementation specific for a conference server.  Thus, the
   conference server first checks all the parameters, before making any
   changes to the internal representation of the conference object.  For
   example, it would be undesirable to change the <subject> of the
   conference, but then detect an invalid URI in one of the <service-
   uris> and abort the remaining updates.  Also, since multiple clients
   can modify the same conference objects, conference clients SHOULD
   first obtain the current object from the conference server and then
   update the relevant data elements in the conference object prior to
   invoking a specific operation on the conference server.  In order to
   effectively manage modifications to conference data, a versioning
   approach is exploited in the CCMP.  More precisely, each conference
   object is associated with a version number indicating the most up to
   date view of the conference at the server's side.  Such version
   number is reported to the clients when answering their requests.  A
   client willing to make modifications to a conference object has to
   send an update message to the server.  In case the modifications are
   all successfully applied, the server sends back to the client a
   "success" response which also carries information about the current
   server-side version of the modified object.  With such approach, a
   client which is working on version "X" of a conference object and
   finds inside a "success" response a version number which is "X+1" can
   be sure that the version it was aware of was the most up to date.  On
   the other hand, if the "success" response carries back a version
   which is at least "X+2", the client can detect that the object that
   has been modified at the server's side was more up to date than the



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   one it was working upon.  This is clearly due to the effect of
   concurrent modification requests issued by independent clients.
   Hence, for the sake of having available the latest version of the
   modified object, the client can send to the conference server a
   further "retrieve" request.  In no case a copy of the conference
   object available at the server is returned to the client as part of
   the update response message.  Such a copy can always be obtained
   through an ad-hoc "retrieve" message.

   Based on the above considerations, all CCMP response messages
   carrying in their body a conference document (or a fragment of it)
   MUST contain a "version" parameter.  This does not hold for request
   messages, for which the "version" parameter is not at all required,
   since it represents useless information for the server: as long as
   the required modifications can be applied to the target conference
   object with no conflicts, the server does not care whether or not the
   client had an up to date view of the information stored at its side.
   This said, it stands clear that a client which has subscribed at the
   server, through the XCON event package [I-D.ietf-xcon-event-package],
   to notifications about conference object modifications, will always
   have the most up to date version of that object available at his
   side.

   A final consideration concerns the relation between the CCMP and the
   main entities it manages, i.e. conference objects.  Such objects have
   to be compliant with the XCON data-model, which identifies some
   elements/attributes as mandatory.  From the CCMP standpoint this can
   become a problem in cases of client-initiated operations, like the
   creation/update of conference objects.  In such cases, not all of the
   mandatory data can be known in advance to the client issuing a CCMP
   request.  As an example, a client has no means to know, at the time
   it issues a conference creation request, the XCON-URI that the server
   will assign to the yet-to-be-created conference and hence it is not
   able to appropriately fill with that value the mandatory "entity"
   attribute of the conference document contained in the request.  To
   solve this kind of issues, the CCMP will fill all mandatory data
   model fields, for which no value is available at the client at the
   time the request is constructed, with fake values in the form of
   wildcard strings (e.g.  AUTO_GENERATE_X, with X being an incremental
   index initialized to a value of 1).  Upon reception of the mentioned
   kinds of requests, the server will: (i) generate the proper
   identifier(s); (ii) produce a response in which the received fake
   identifier(s) carried in the request has (have) been replaced by the
   newly created one(s).  With this approach we maintain compatibility
   with the data model requirements, at the same time allowing for
   client-initiated manipulation of conference objects at the server's
   side (which is, by the way, one of the main goals for which the CCMP
   protocol has been conceived at the outset).



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5.2.  Implementation Approach

   There have been a number of different proposals as to the most
   suitable implementation solution for the CCMP.  A non-exhaustive
   summary of the most interesting ones is provided in Appendix A.  The
   solution for the CCMP defined in this document is viewed as a good
   compromise amongst the most notable past candidates and is referred
   to as "HTTP single-verb transport plus CCMP body".  With this
   approach, CCMP is able to take advantage of existing HTTP
   functionality.  As with SOAP, the CCMP uses a "single HTTP verb" for
   transport (i.e. a single transaction type for each request/response
   pair); this allows decoupling CCMP messages from HTTP messages.
   Similarly, as with any RESTful approach, CCMP messages are inserted
   directly in the body of HTTP messages, thus avoiding any unnecessary
   processing and communication burden associated with further
   intermediaries.  With this approach, no modification to the CCMP
   messages/operations is required to use a different transport
   protocol.

   The remainder of this document focuses on the selected approach.  The
   CCMP protocol inserts XML-based CCMP requests into the body of HTTP
   POST operations and retrieves responses from the body of HTTP "200
   OK" messages.  CCMP messages have a MIME-type of "application/
   ccmp+xml", which appears inside the "Content-Type" and "Accept"
   fields of HTTP requests and responses.  Section 10 provides the
   complete requirements for an HTTP implementation to support the CCMP.

























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6.  CCMP messages

   CCMP messages are either requests or responses.  The general CCMP
   request message is defined in Section 6.1.  The general CCMP response
   message is defined in Section 6.2.  The details of the specific
   message type which is carried in the CCMP request and response
   messages are described in Section 6.3.  CCMP response codes are
   listed in Section 6.4

6.1.  CCMP Request Message Type

   A CCMP request message is comprised of the following parameters:

   subject:  An optional parameter containing username and password of
      the client registered at the conferencing system.  Each user who
      subscribes to the conferencing system is assumed to be equipped
      with those credentials and SHOULD enclose them in each CCMP
      request she issues.  These fields can be used to control that the
      user sending the CCMP request has the authority to perform the
      entailed operation.  The same fields can also be exploited to
      carry out other Authorization, Authentication and Accounting (AAA)
      procedures.

   confUserID:  An optional parameter containing the XCON-USERID of the
      client.  The XCON-USERID is used to identify any conferencing
      client within the context of the conferencing system and it is
      assinged by the conferencing server at each conferencing client
      who interacts with it.  The "confUserID" parameter is REQUIRED in
      the CCMP request and response messages with the exception of the
      case of a user who has no XCON-USERID and who wants to enter, via
      CCMP, a conference whose identifier is known.  In such case, a
      side-effect of the request is that the user is provided with an
      appropriate XCON-USERID.  An example of the above mentioned case
      will be provided in Section 6.3.6.

   confObjID:  An optional parameter containing the XCON-URI of the
      target conference object.

   operation:  An optional parameter refining the type of specialized
      request message.  The "operation" parameter is REQUIRED in all
      requests except for the "blueprintsRequest" and "confsRequest"
      specialized messages.

   conference-password:  An optional parameter that MUST be inserted in
      all requests whose target conference object is password-protected
      (as per the <conference-password> element in
      [I-D.ietf-xcon-common-data-model]).




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   specialized request message:  This is specialization of the generic
      request message (e.g., blueprintsRequest), containing parameters
      that are dependent on the specific request sent to the server.  A
      specialized request message MUST be included in the CCMP request
      message.  The details for the specialized messages and associated
      parameters are provided in Section 6.3.



   <!-- Definition of CCMP Request -->

   <xs:element name="ccmpRequest" type="ccmp-request-type" />

   <!-- Definition of ccmp-request-type-->

   <xs:complexType name="ccmp-request-type">
       <xs:sequence>
           <xs:element name="ccmpRequest"
                       type="ccmp-request-message-type" />
       </xs:sequence>
   </xs:complexType>

    <!--  Definition of ccmp-request-message-type -->

    <xs:complexType abstract="true"
                    name="ccmp-request-message-type">
        <xs:sequence>
            <xs:element name="subject" type="subject-type"
                        minOccurs="0" maxOccurs="1" />
            <xs:element name="confUserID" type="xs:string"
                        minOccurs="0" maxOccurs="1" />
            <xs:element name="confObjID" type="xs:string"
                        minOccurs="0" maxOccurs="1" />
            <xs:element name="operation" type="operationType"
                        minOccurs="0" maxOccurs="1" />
            <xs:element name="conference-password" type="xs:string"
                        minOccurs="0" maxOccurs="1" />
            <xs:any namespace="##other" processContents="lax"
                    minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>


               Figure 2: Structure of CCMP Request messages






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6.2.  CCMP Response Message Type

   A CCMP response message is comprised of the following parameters:

   confUserID:  A mandatory parameter in CCMP response messages
      containing the XCON-USERID of the conferencing client who issued
      the CCMP request message.

   confObjID:  An optional parameter containing the XCON-URI of the
      target conference object.

   operation:  An optional parameter for CCMP response messages.  This
      parameter is REQUIRED in all responses except for the
      "blueprintsResponse" and "confsResponse" specialized messages.

   response-code:  A mandatory parameter containing the response code
      associated with the request.  The response code MUST be chosen
      from the codes listed in Section 6.4.

   response-string:  An optional reason string associated with the
      response.  In case of an error, in particular, such string can be
      used to provide the client with detailed information about the
      error itself.

   version:  An optional parameter reflecting the current version number
      of the conference object referred by the confObjID.  This number
      is contained in the "version" attribute of the <conference-info>
      element related to that conference.

   specialized response message:  This is specialization of the generic
      response message, containing parameters that are dependent on the
      specific request sent to the server (e.g., blueprintsResponse).  A
      specialized response message SHOULD be included in the CCMP
      response message, except in an error situation where the CCMP
      request message did not contain a valid specialized message.  In
      this case, the conference server MUST return a "response-code" of
      "badRequest".  The details for the specialized messages and
      associated parameters are provided in Section 6.3.













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   <!-- Definition of CCMP Response -->

   <xs:element name="ccmpResponse" type="ccmp-response-type" />

   <!-- Definition of ccmp-response-type -->

   <xs:complexType name="ccmp-response-type">
       <xs:sequence>
           <xs:element name="ccmpResponse"
                       type="ccmp-response-message-type" />
       </xs:sequence>
   </xs:complexType>

   <!--  Definition of ccmp-response-message-type -->

   <xs:complexType abstract="true"
                   name="ccmp-response-message-type">
       <xs:sequence>
           <xs:element name="confUserID" type="xs:string"
                       minOccurs="1" maxOccurs="1" />
           <xs:element name="confObjID" type="xs:string"
                       minOccurs="0" maxOccurs="1" />
           <xs:element name="operation" minOccurs="0"
                       maxOccurs="1" />
           <xs:element ref="response-code" minOccurs="1"
                       maxOccurs="1" />
           <xs:element name="response-string" type="xs:string"
                       minOccurs="0" maxOccurs="1" />
           <xs:element name="version" type="xs:positiveInteger"
                       minOccurs="0" maxOccurs="1" />
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>


               Figure 3: Structure of CCMP Response message

6.3.  Detailed messages

   Based on the request and response message structures described in
   Section 6.1 and Section 6.2, the following summarizes the specialized
   CCMP request/response types described in this document:

   1.   blueprintsRequest/blueprintsResponse





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   2.   confsRequest/confsResponse

   3.   blueprintRequest/blueprintResponse

   4.   confRequest/confResponse

   5.   usersRequest/usersResponse

   6.   userRequest/userResponse

   7.   sidebarsByValRequest/sidebarsByValResponse

   8.   sidebarsByRefRequest/sidebarsByRefResponse

   9.   sidebarByValRequest/sidebarByValResponse

   10.  sidebarByRefRequest/sidebarByRefResponse

   These CCMP request/response pairs use the fundamental CCMP operations
   as defined in Section 5.1 to manipulate the conference data.  Table 1
   summarizes the CCMP operations and corresponding actions that are
   valid for a specific CCMP request type, noting that neither the
   blueprintsRequest/blueprintsResponse nor confsRequest/confsResponse
   require an "operation" parameter.  The corresponding response MUST
   contain the same operation.  Note that some entries are labeled "N/A"
   indicating the operation is invalid for that request type.  In the
   case of an "N/A*", the operation MAY be allowed for specific
   privileged users or system administrators, but is not part of the
   functionality included in this document.






















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   +---------------+------------+------------+------------+------------+
   | Operation     |  Retrieve  |   Create   |   Update   |   Delete   |
   | ------------- |            |            |            |            |
   | Request Type  |            |            |            |            |
   +---------------+------------+------------+------------+------------+
   | blueprints    |  Get list  |     N/A    |     N/A    |     N/A    |
   | Request       |     of     |            |            |            |
   |               | blueprints |            |            |            |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | blueprint     |     Get    |    N/A*    |    N/A*    |    N/A*    |
   | Request       |  blueprint |            |            |            |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | confsRequest  |  Get list  |     N/A    |     N/A    |     N/A    |
   |               |  of confs  |            |            |            |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | confRequest   |    Gets    |   Creates  |   Changes  |   Deletes  |
   |               | conference | conference | conference | conference |
   |               |   object   |   object   |   object   |   object   |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | usersRequest  |    Gets    |   N/A(**)  |   Changes  |   N/A(**)  |
   |               |   <users>  |            |   <users>  |            |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | userRequest   |    Gets    |   Adds a   |   Changes  |   Deletes  |
   |               |  specified |  <user> to |  specified |  specified |
   |               |   <user>   |   a conf   |   <user>   |   <user>   |
   |               |            |    (***)   |            |            |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | sidebarsByVal |    Gets    |     N/A    |     N/A    |     N/A    |
   | Request       | <sidebars- |            |            |            |
   |               |   by-val>  |            |            |            |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | sidebarsByRef |    Gets    |     N/A    |     N/A    |     N/A    |
   | Request       | <sidebars- |            |            |            |
   |               |   by-ref>  |            |            |            |



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   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | sidebarByVal  |    Gets    |   Creates  |   Changes  |   Deletes  |
   | Request       |  sidebar-  |  sidebar-  |  sidebar-  |  sidebar-  |
   |               |   by-val   |   by-val   |   by-val   |   by-val   |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | sidebarByRef  |    Gets    |   Creates  |   Changes  |   Deletes  |
   | Request       |  sidebar-  |  sidebar-  |  sidebar-  |  sidebar-  |
   |               |   by-ref   |   by-ref   |   by-ref   |   by-ref   |
   +---------------+------------+------------+------------+------------+

            Table 1: Request Type Operation Specific Processing

   (**): These operations are not allowed for a usersRequest message,
   since the <users> section, which is the target element of such a
   request, is created and removed in conjuntcion with, respectively,
   the creation and deletion of the associated conference document.
   Thus, "update" and "retrieve" are the only semantically correct
   operations for such message.

   (***): This operation can involve the creation of an XCON-USERID, if
   the sender does not add it in the "confUserID" parameter, and/or if
   the "entity" field of the "userInfo" parameter is void.

   Additional parameters included in the specialized CCMP request/
   response messages are detailed in the subsequent sections.

6.3.1.  blueprintsRequest and blueprintsResponse

   A "blueprintsRequest" (Figure 4) message is sent to request the list
   of XCON-URIs associated with the available blueprints from the
   conference server.  Such URIs can be subsequently used by the client
   to access detailed information about a specified blueprint with a
   specific blueprintRequest message per Section 6.3.3.  The
   "confUserID" parameter MUST be included in every blueprintsRequest/
   Response message and reflect the XCON-USERID of the conferencing
   client issuing the request.  A blueprintsRequest message REQUIRES no
   "confObjID" and "operation" parameters, since it is not targetted to
   a specific conference instance and it is conceived as a "retrieve-
   only" request.  In order to obtain a specific subset of the available
   blueprints, a client may specify a selection filter providing an
   appropriate xpath query in the optional "xpathFilter" parameter of
   the request.  For example, to select blueprints having both audio and
   video stream support, a possible xpathFilter value could be: "/
   conference-info[conference-description/available-media/entry/
   type='audio' and conference-description/available-media/entry/



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   type='video']".

   The associated "blueprintsResponse" message SHOULD contain, as shown
   in Figure 4, a "blueprintsInfo" parameter containing the above
   mentioned XCON-URI list.



 <!-- blueprintsRequest -->

 <xs:complexType name="ccmp-blueprints-request-message-type">
     <xs:complexContent>
         <xs:extension base="tns:ccmp-request-message-type">
             <xs:sequence>
                 <xs:element ref="blueprintsRequest" />
             </xs:sequence>
         </xs:extension>
     </xs:complexContent>
 </xs:complexType>

 <!-- blueprintsRequestType -->

 <xs:element name="blueprintsRequest" type="blueprintsRequestType"/>

 <xs:complexType name="blueprintsRequestType">
     <xs:sequence>
         <xs:element name="xpathFilter" type="xs:string" minOccurs="0"/>
         <xs:any namespace="##other" processContents="lax"
                 minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:anyAttribute namespace="##any" processContents="lax"/>
 </xs:complexType>

 <!-- blueprintsResponse -->

 <xs:complexType name="ccmp-blueprints-response-message-type">
     <xs:complexContent>
         <xs:extension base="tns:ccmp-response-message-type">
             <xs:sequence>
                 <xs:element ref="blueprintsResponse" />
             </xs:sequence>
         </xs:extension>
     </xs:complexContent>
 </xs:complexType>

 <!-- blueprintsResponseType -->

 <xs:element name="blueprintsResponse" type="blueprintsResponseType"/>



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 <xs:complexType name="blueprintsResponseType">
     <xs:sequence>
         <xs:element name="blueprintsInfo"
                     type="info:uris-type" minOccurs="0"/>
         <xs:any namespace="##other" processContents="lax"
                 minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:anyAttribute namespace="##any" processContents="lax"/>
 </xs:complexType>


    Figure 4: Structure of the blueprintsRequest and blueprintsResponse
                                 messages

6.3.2.  confsRequest and confsResponse

   A "confsRequest" message is used to retrieve, from the server, the
   list of XCON-URIs associated with active and registered conferences
   currently handled by the conferencing system.  The "confUserID"
   parameter MUST be included in every confsRequest/Response message and
   reflect the XCON-USERID of the conferencing client issuing the
   request.  The "confObjID" parameter MUST NOT be included in the
   confsRequest message.  The "confsRequest" message is of a "retrieve-
   only" type, since the sole purpose is to collect information
   available at the conference server.  Thus, an "operation" parameter
   MUST NOT be included in a "confsRequest" message.  In order to
   retrieve a specific subset of the available conferences, a client may
   specify a selection filter providing an appropriate xpath query in
   the optional "xpathFilter" parameter of the request.  For example, to
   select only the registered conferences, a possible xpathFilter value
   could be: "/conference-info[conference-description/conference-state/
   active='false']".  The associated "confsResponse" message SHOULD
   contain the list of XCON-URIs in the "confsInfo" parameter.  A user,
   upon receipt of the response message, can interact with the available
   conference objects through further CCMP messages.


 <!-- confsRequest -->

 <xs:complexType name="ccmp-confs-request-message-type">
     <xs:complexContent>
         <xs:extension base="tns:ccmp-request-message-type">
             <xs:sequence>
                 <xs:element ref="confsRequest" />
             </xs:sequence>
         </xs:extension>
     </xs:complexContent>
 </xs:complexType>



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 <!-- confsRequestType -->

 <xs:element name="confsRequest" type="confsRequestType" />

 <xs:complexType name="confsRequestType">
     <xs:sequence>
         <xs:element name="xpathFilter" type="xs:string" minOccurs="0"/>
         <xs:any namespace="##other" processContents="lax"
                 minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:anyAttribute namespace="##any" processContents="lax"/>
 </xs:complexType>

 <!-- confsResponse -->

 <xs:complexType name="ccmp-confs-response-message-type">
     <xs:complexContent>
         <xs:extension base="tns:ccmp-response-message-type">
             <xs:sequence>
                 <xs:element ref="confsResponse" />
             </xs:sequence>
         </xs:extension>
     </xs:complexContent>
 </xs:complexType>

 <!-- confsResponseType -->

 <xs:element name="confsResponse" type="confsResponseType"/>

 <xs:complexType name="confsResponseType">
     <xs:sequence>
         <xs:element name="confsInfo" type="info:uris-type"
                     minOccurs="0"/>
         <xs:any namespace="##other" processContents="lax"
                 minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:anyAttribute namespace="##any" processContents="lax"/>
 </xs:complexType>


    Figure 5: Structure of the confsRequest and confsResponse messages

6.3.3.  blueprintRequest and blueprintResponse

   Through a "blueprintRequest", a client can manipulate the conference
   object associated with a specified blueprint.  Further than the
   "confUserID" parameter, the request MUST include the "confObjID" and
   the "operation" one.  Again, the "confUserID" parameter MUST be



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   included in every blueprintRequest/Response message and reflect the
   XCON-USERID of the conferencing client issuing the request.  The
   "confObjID" parameter MUST contain the XCON-URI of the blueprint,
   which might have been previously retrieved through a
   "blueprintsRequest" message.

   The blueprintRequest message SHOULD NOT contain an "operation"
   parameter other than "retrieve".  The "create", "update" and "delete"
   operations SHOULD NOT be included in a "blueprintRequest" message
   except in the case of privileged users (e.g. the conference server
   administration staff), who might authenticate themselves by the mean
   of the "subject" request parameter.

   A blueprintRequest/retrieve carrying a "confObjID" which is not
   associated with one of the available system's blueprints will
   generate, on the server's side, a blueprintResponse message
   containing an "objectNotFound" error code.  This holds also for the
   case in which the mentioned "confObjID" is related to an existing
   conference document stored at the server, but associated with an
   actual conference (be it active or registered) or with a sidebar
   rather than a blueprint.

   In the case of "response-code" of "success" for a "retrieve"
   operation, the "blueprintInfo" parameter MUST be included in the
   "blueprintResponse" message.  The "blueprintInfo" parameter contains
   the conference document associated with the blueprint as identified
   by the "confObjID" parameter specified in the blueprintRequest.



   <!--  blueprintRequest -->

   <xs:complexType name="ccmp-blueprint-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="blueprintRequest" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- blueprintRequestType -->

   <xs:element name="blueprintRequest" type="blueprintRequestType" />

   <xs:complexType name="blueprintRequestType">
       <xs:sequence>



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           <xs:element name="blueprintInfo"
                       type="info:conference-type" minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!-- blueprintResponse -->

   <xs:complexType name="ccmp-blueprint-response-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-response-message-type">
               <xs:sequence>
                   <xs:element ref="blueprintResponse" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- blueprintResponseType -->

   <xs:element name="blueprintResponse" type="blueprintResponseType"/>

   <xs:complexType name="blueprintResponseType">
       <xs:sequence>
           <xs:element name="blueprintInfo" type="info:conference-type"
                       minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded">
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>


     Figure 6: Structure of the blueprintRequest and blueprintResponse
                                 messages

6.3.4.  confRequest and confResponse

   With a "confRequest" message, CCMP clients can manipulate conference
   objects associated with either active or registered conferences.  The
   "confUserID" parameter MUST be included in every confRequest/Response
   message and reflect the XCON-USERID of the conferencing client
   issuing the request.  ConfRequest and confResponse messages MUST also
   include an "operation" parameter.  ConfResponse messages MUST return
   to the requestor a "response-code" and MAY contain a "response-
   string" explaining it.  Depending upon the type of "operation", a



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   "confObjID" and "confInfo" parameter MAY be included in the
   confRequest and response.  The requirements for inclusion of
   "confObjID" and "confInfo" parameter in the confRequest/confResponse
   messages and are detailed below for each "operation" case.

   The creation case deserves care.  To create a new conference through
   a "confRequest" message, two approaches can be considered:

   1.  Creation through explicit cloning: the "confObjID" parameter MUST
       contain the XCON-URI of the blueprint or of the conference to be
       cloned, while the "confInfo" parameter MUST NOT be included in
       the confRequest;

   2.  Creation through implicit cloning (also known as "direct
       creation"): the "confObjID" parameter MUST NOT be included in the
       request and the CCMP client can describe the desired conference
       to be created using the "confInfo" parameter.  If no "confInfo"
       parameter is provided in the request, the new conference will be
       created as a clone of the system default blueprint.

   In both creation cases, the confResponse, for a successful completion
   of a "create" operation, contains a response-code of "success" and
   MUST contain the XCON-URI of the newly created conference in the
   "confObjID" parameter, in order to allow the conferencing client to
   manipulate that conference through following CCMP requests.  In
   addition, the "confInfo" parameter transporting the created
   conference document MAY be included, at the discretion of the
   conferencing system implementation, along with an optional version
   parameter initialized at "1", since immediatly upon the creation the
   conference object is at its first version.

   In the case of a confRequest with a "retrieve" operation, the
   "confObjID" representing the XCON-URI of the target conference MUST
   be included and the "confInfo" parameter MUST NOT be included in the
   request.  The conferencing server MUST ignore any "confInfo"
   parameter that is received in a confRequest/retrieve.  If the
   confResponse for the "retrieve" operation contains a "response-code"
   of "success", the "confInfo" parameter MUST be included in the
   response.  The "confInfo" parameter MUST contain the entire
   conference document describing the target conference object in its
   current state.  The current state of the retrieved conference object
   MUST also be reported in the proper "version" response parameter.

   In case of a confRequest with an "update" operation, the "confInfo"
   and "confObjID" MUST be included in the request.  The "confInfo"
   represents an object of type "conference-type" containing all the
   changes to be applied to the conference whose identifier is
   "confObjID".  Note that, in such a case, though the confInfo



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   parameter has indeed to follow the rules indicated in the XCON data
   model, it does not represent the entire updated version of the target
   conference, since it rather conveys just the modifications to apply
   to that conference.  For example, in order to change the conference
   title, the confInfo parameter will be of the form:


   <confInfo entity="xcon:8977777@example.com">
     <conference-description>
       <display-text> *** NEW CONFERENCE TITLE *** </display-text>
     </conference-description>
   </confInfo>


     Figure 7: Updating a conference object: modifying the title of a
                                conference

   Similarly, to remove the title of an existing conference, a
   confRequest/update carrying the following "confInfo" parameter would
   do the job.:



   <confInfo entity="xcon:8977777@example.com">
     <conference-description>
       <display-text/>
     </conference-description>
   </confInfo>


      Figure 8: Updating a conference object: removing the title of a
                                conference

   In the case of a confResponse/update with a response-code of
   "success", no additional information is required in the response
   message, which means the return of confInfo parameter is not
   mandatory.  A following confRequest/retrieve transaction might
   provide the CCMP client with the current aspect of the conference
   upon the modification, or the Notification Protocol might address
   that task as well.  A "success" response-code indicates that the
   referenced conference document has been changed accordingly to the
   request by the conferencing server.  The "version" parameter MUST be
   enclosed in the confResponse/update message, in order to let the
   client understand what is the actual current conference-object
   version, upon the applied modifications.  An "updateFailed" response-
   code indicates that the changes reflected in the request "confInfo"
   are not feasible.  This could be due to policies, requestor roles,
   specific privileges, unacceptable values etc., with the reason



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   specific to a conferencing system and its configuration.  Together
   with the "updateFailed" response-code, the "version" parameter MUST
   be attached in the confResponse/update, by this way allowing the
   client to eventually retrieve the current version of the target
   conference if the one she attempted to modify was not the most up-to-
   date.

   In the case of a confRequest with a "delete" operation, the
   "confObjID" representing the XCON-URI of the target conference MUST
   be included while the "confInfo" MUST NOT be included in the request.
   The conferencing server MUST ignore any "confInfo" parameter that is
   received within such a request.  The confResponse MUST contain the
   same "confObjID" that was included in the confRequest.  If the
   confResponse/delete operation contains a "success" response-code, the
   conference indicated in the "confObjID" has been succesfully deleted.
   A "success" confResponse/delete MUST NOT contain the "confInfo"
   parameter.  The "version" parameter SHOULD NOT be returned in any
   confResponse/delete.  If the conferencing server cannot delete the
   conference referenced by the "confObjID" received in the confRequest
   because it is the parent of another conference object that is in use,
   the conferencing server MUST return a response-code of
   "deleteParentFailed".

   A confRequest with an "operation" of "retrieve", "update" or "delete"
   carrying a "confObjID" which is not associated with one of the
   conferences (active or registered) the system is holding will
   generate, on the server's side, a confResponse message containing an
   "objectNotFound" error code.  This holds also for the case in which
   the mentioned "confObjID" is related to an existing conference object
   stored at the server, but associated with a blueprint or with a
   sidebar rather than an actual conference.

   The schema for the confRequest/confResponse pair is shown in
   Figure 9.


   <!-- confRequest -->

   <xs:complexType name="ccmp-conf-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="confRequest" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>




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   <!-- confRequestType -->

   <xs:element name="confRequest" type="confRequestType" />

   <xs:complexType name="confRequestType">
       <xs:sequence>
           <xs:element name="confInfo" type="info:conference-type"
                       minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!-- confResponse -->

   <xs:complexType name="ccmp-conf-response-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-response-message-type">
               <xs:sequence>
                   <xs:element ref="confResponse" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- confResponseType -->

   <xs:element name="confResponse" type="confResponseType" />

   <xs:complexType name="confResponseType">
       <xs:sequence>
           <xs:element name="confInfo" type="info:conference-type"
                       minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>


     Figure 9: Structure of the confRequest and confResponse messages

6.3.5.  usersRequest and usersResponse

   Through a "usersRequest" message the CCMP client manipulates the XML
   <users> element of the conference document associated with the
   conference identified by the "confObjID" parameter complusory



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   included in the request.  Inside the <users> element, along with the
   list of <user> elements associated with conference participants,
   there is information that the client may be interested in
   controlling, such the list of the users to which access to the
   conference is allowed/denied, conference participation policies,
   etc.; for this reason, a customized message has been designed to
   allow for the manipulation of this specific part of a conference
   document.

   A "usersInfo" parameter MAY be included in a usersRequest message
   depending upon the operation.  If the "usersInfo" parameter is
   included in the usersRequest message, the parameter MUST be compliant
   with the <users> field of the XCON data model.

   Two operations are allowed for a "usersRequest" message:

   1.  "retrieve": In this case the request MUST NOT include a
       "usersInfo" parameter, while a successful response MUST contain
       the desired <users> element in the "usersInfo" parameter.  The
       conference server MUST ignore a "usersInfo" parameter if it is
       received in a request with a "retrieve" operation.

   2.  update: In this case, the "usersInfo" parameter MUST contain the
       modifications to be applied to the referred <users> element.  If
       the "response-code" is "success", then the "usersInfo" parameter
       SHOULD NOT be returned.  Any "usersInfo" parameter that is
       returned SHOULD be ignored.  A "response-code" of
       "forbiddenChangeProtected" indicates that the conferencing client
       is not allowed to make the changes reflected in the "usersInfo"
       contained in the usersRequest message.  This could be due to
       policies, roles, specific privileges, etc., with the reason
       specific to a conferencing system and its configuration.

   Operations of "create" and "delete" are not applicable to a
   usersRequest message and MUST NOT be considered by the server, which
   means that a "response-code" of "forbidden" MUST be included in the
   usersResponse message.




   <!-- usersRequest -->

   <xs:complexType name="ccmp-users-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="usersRequest" />



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               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- usersRequestType -->

   <xs:element name="usersRequest" type="usersRequestType" />

   <xs:complexType name="usersRequestType">
       <xs:sequence>
           <xs:element name="usersInfo"
                       type="info:users-type" minOccurs="0" />
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!-- usersResponse -->

   <xs:complexType name="ccmp-users-response-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-response-message-type">
               <xs:sequence>
                   <xs:element ref="usersResponse" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- usersResponseType -->

   <xs:element name="usersResponse" type="usersResponseType" />

   <xs:complexType name="usersResponseType">
       <xs:sequence>
           <xs:element name="usersInfo" type="info:users-type"
                       minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>


    Figure 10: Structure of the usersRequest and usersResponse messages




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6.3.6.  userRequest and userResponse

   A "userRequest" message is used to manipulate <user> elements inside
   a conference document associated with a conference identified by the
   "confObjID" parameter.  Besides retrieving information about a
   specific conference user, the message is used to request that the
   conference server either create, modify, or delete information about
   a user.  A "userRequest" message MUST include the "confObjID", the
   "operation" parameter, and MAY include a "userInfo" parameter
   containing the detailed user's information depending upon the
   operation and whether the "userInfo" has already been populated for a
   specific user.  Note that a user may not necessarily be a
   conferencing control client (i.e., some participants in a conference
   are not "XCON aware").

   An XCON-USERID SHOULD be assigned to each and every user subscribed
   to the system.  In such a way, a user who is not a conference
   participant can make requests (provided she has successfully passed
   AAA checks), like creating a conference, retrieving conference
   information, etc..

   Conference users can be created in a number of different ways.  In
   each of these cases the operation MUST be set to "create" in the
   userRequest message.  Each of the userResponse messages for these
   cases MUST include the "confObjID", "confUserID", "operation" and
   "response-code" parameters.  In the case of a response code of
   "success", the userResponse message MAY include the "userInfo"
   parameter depending upon the manner in which the user was created:

   o  Conferencing client with an XCON-USERID adds itself to the
      conference: In this case, the "userInfo" parameter MAY be included
      in the userRequest.  The "userInfo" parameter MUST contain a
      <user> element (compliant with the XCON data model) and the
      "entity" attribute MUST be set to a value which represents the
      XCON-USERID of the user initiating the request.  No additional
      parameters beyond those previously described are required in the
      userResponse message, in the case of a "response-code" of
      "success".

   o  Conferencing client acts on behalf of a third user whose XCON-
      USERID is known: in this case, the "userInfo" parameter MUST be
      included in the userRequest.  The "userInfo" parameter MUST
      contain a <user> element and the "entity" attribute value MUST be
      set to the XCON-USERID of the third user in question.  No
      additional parameters beyond those previously described are
      required in the userResponse message, in the case of a "response-
      code" of "success".




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   o  A conferencing client who has no XCON-USERID and who wants to
      enter, via CCMP, a conference whose identifier is known.  In such
      case, a side-effect of the request is that the user is provided
      with a new XCON-USERID (created by the server) carried inside the
      "confUserID" parameter of the response.  This is the only case in
      which a CCMP request can be valid though carrying a void
      "confUserID" parameter.  A "userInfo" parameter MUST be enclosed
      in the request, providing at least a contact URI of the joining
      client, in order to let the focus instigate the signaling phase
      needed to add her to the conference.  The mandatory "entity"
      attribute of the "userInfo" parameter in the request is filled
      with a dummy value recognizable on the server side, so to conform
      to the rules contained in the XCON data model XML schema.  The
      involved messages (userRequest and userResponse) in such case
      should look like the following:




   Request fields:

   confUserID=null;
   confObjID=confXYZ;
   operation=create;
   userInfo=

   <userInfo entity="xcon-userid:AUTO_GENERATE@example.com">
           <endpoint entity="sip:GHIL345@blablabla">
           ...


   Response fields (in case of success):

   confUserID=user345;
   confObjID=confXYZ;
   operation=create;
   response-code=success;
   userInfo=null; //or the entire userInfo object




      Figure 11: userRequest and userResponse in the absence of an xcon-
                                    userid

   o  Conferencing client is unaware of the XCON-USERID of a third user:
      In this case, the XCON-USERID in the request "confUserID" is the
      sender's one and the "entity" attribute of the attached userInfo



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      is filled with the pre-defined fake value
      "xcon-userid:AUTO_GENERATE@example.com".  The XCON-USERID for the
      third user MUST be returned to the client issuing the request in
      the "entity" attribute of the response "userInfo" parameter, if
      the "response-code" is "success".  [RP] This scenario is intended
      to support both the case where a brand new conferencing system
      user is added to a conference by a third party (i.e. a user who is
      not yet provided with an XCON-USERID) and the case where the CCMP
      client issuing the request does not know the to-be-added user's
      XCON-USERID (which means such an identifier could already exist on
      the server's side for that user).  In this last case, the
      conferencing server is in charge of avoiding XCON-URI duplicates
      for the same conferencing client, looking at key fields in the
      request provided "userInfo" parameter, such as the signalling URI:
      if the joining user is a brand new one, then the generation of a
      new XCON identifier is needed; otherwise, if that user is an
      existing one, the server must recover the corresponding XCON
      identifier.

   In the case of a userRequest with a "retrieve" operation, the
   "confObjID" representing the XCON-URI of the target conference MUST
   be included.  The "confUserID", containing the CCMP client's xcon-
   userid, MUST also be included in the userRequest message.  If the
   client wants to retrieve information about her profile in the
   specified conference, no "userInfo" parameter is needed in the
   retrieve request.  On the other hand, if the client wants to obtain
   someone else's info within the given conference, she MUST include in
   the userRequest/retrieve a "userInfo" parameter whose "entity"
   attribute conveys the desired user's xcon-userid.  If the
   userResponse for the "retrieve" operation contains a "response-code"
   of "success", the "userInfo" parameter MUST be included in the
   response.

   In case of a userRequest with an "update" operation, the "confObjID",
   "confUserID" and "userInfo" MUST be included in the request.  The
   "userInfo" is of type "user-type" and contains all the changes to be
   applied to a specific <user> element in the conference object
   identified by the "confObjID" in the userRequest message.  The user
   to be modified is identified through the "entity" attribute of the
   "userInfo" parameter included in the request.  In the case of a
   userResponse with a "response-code" of "success", no additional
   information is required in the "userResponse" message.  A "response-
   code" of "success" indicates that the referenced user element has
   been updated by the conference server.  A "response-code" of
   "forbiddenChangeProtected" indicates that the conferencing client is
   not allowed to make the changes reflected in the "userInfo" in the
   initial request.  This could be due to policies, roles, specific
   privileges, etc., with the reason specific to a conferencing system



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   and its configuration.

   In the case of a userRequest with a "delete" operation, the
   "confObjID" representing the XCON-URI of the target conference MUST
   be included.  The "confUserID", containing the CCMP client's xcon-
   userid, MUST be included in the userRequest message.  If the client
   wants to exit the specified conference, no "userInfo" parameter is
   needed in the delete request.  On the other hand, if the client wants
   to remove another participant from the given conference, she MUST
   include in the userRequest/delete a "userInfo" parameter whose
   "entity" attribute conveys the xcon-userid of that participant.  The
   userResponse MUST contain the same "confObjID" that was included in
   the userRequest.  The userResponse MUST contain a "response-code" of
   "success" if the target <user> element has been successfully deleted.
   If the userResponse for the "delete" operation contains a "response-
   code" of "success", the userResponse MUST NOT contain the "userInfo"
   parameter.


   <!-- userRequest -->

   <xs:complexType name="ccmp-user-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="userRequest" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- userRequestType -->

   <xs:element name="userRequest" type="userRequestType" />

   <xs:complexType name="userRequestType">
       <xs:sequence>
           <xs:element name="userInfo"
                       type="info:user-type" minOccurs="0" />
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!-- userResponse -->

   <xs:complexType name="ccmp-user-response-message-type">



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       <xs:complexContent>
           <xs:extension base="tns:ccmp-response-message-type">
               <xs:sequence>
                   <xs:element ref="userResponse" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- userResponseType -->

   <xs:element name="userResponse" type="userResponseType" />

   <xs:complexType name="userResponseType">
       <xs:sequence>
           <xs:element name="userInfo" type="info:user-type
                       minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>


     Figure 12: Structure of the userRequest and userResponse messages

6.3.7.  sidebarsByValRequest and sidebarsByValResponse

   A "sidebarsByValRequest" is used to execute a retrieve-only operation
   on the <sidebars-by-val> field of the conference object represented
   by the "confObjID".  The "sidebarsByValRequest" message is of a
   "retrieve-only" type, so an "operation" parameter MUST NOT be
   included in a "sidebarsByValRequest" message.  As with blueprints and
   conferences, also with sidebars, CCMP allows for the use of xpath
   filters whenever a selected subset of the sidebars available at the
   server's side has to be retrieved by the client.  This applies both
   to sidebars by reference and to sidebars by value.  A
   "sidebarsByValResponse" with a "response-code" of "success" MUST
   contain a "sidebarsByValInfo" parameter containing the desired
   <sidebars-by-val> element.  A "sidebarsByValResponse" message MUST
   carry back to the client a "version" element related to the current
   version of the main conference object (i.e. the one whose identifier
   is contained in the "confObjId" field of the request) to which the
   sidebars in question are associated.  The "sidebarsByValInfo"
   parameter contains the list of the conference objects associated with
   the sidebars by value derived from the main conference.  The
   retrieved sidebars can then be updated or deleted using the
   "sidebarByValRequest" message, which is described in Section 6.3.8.



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 <!-- sidebarsByValRequest -->

 <xs:complexType name="ccmp-sidebarsByVal-request-message-type">
     <xs:complexContent>
         <xs:extension base="tns:ccmp-request-message-type">
             <xs:sequence>
                 <xs:element ref="sidebarsByValRequest"/>
             </xs:sequence>
         </xs:extension>
    </xs:complexContent>
 </xs:complexType>

 <!-- sidebarsByValRequestType -->

 <xs:element name="sidebarsByValRequest"
             type="sidebarsByValRequestType" />

 <xs:complexType name="sidebarsByValRequestType">
     <xs:sequence>
         <xs:element name="xpathFilter" type="xs:string" minOccurs="0"/>
         <xs:any namespace="##other" processContents="lax"
                 minOccurs="0" maxOccurs="unbounded"/>
   </xs:sequence>
   <xs:anyAttribute namespace="##any" processContents="lax"/>
 </xs:complexType>


 <!-- sidebarsByValResponse -->

 <xs:complexType name="ccmp-sidebarsByVal-response-message-type">
         <xs:complexContent>
          <xs:extension base="tns:ccmp-response-message-type">
                 <xs:sequence>
            <xs:element ref="sidebarsByValResponse"/>
           </xs:sequence>
          </xs:extension>
         </xs:complexContent>
 </xs:complexType>

 <!-- sidebarsByValResponseType -->

 <xs:element name="sidebarsByValResponse"
             type="sidebarsByValResponseType" />

 <xs:complexType name="sidebarsByValResponseType">
     <xs:sequence>
         <xs:element name="sidebarsByValInfo"
                     type="info:sidebars-by-val-type" minOccurs="0"/>



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         <xs:any namespace="##other" processContents="lax"
                 minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
    <xs:anyAttribute namespace="##any" processContents="lax"/>
 </xs:complexType>



           Figure 13: Structure of the sidebarsByValRequest and
                      sidebarsByValResponse messages

6.3.8.  sidebarByValRequest and sidebarByValResponse

   A sidebarByValRequest message MUST contain the "operation" parameter
   which discriminates among retrieval, creation, modification and
   deletion of a specific sidebar.  The other required parameters depend
   upon the type of operation.

   In the case of a "create" operation, the "confObjID" parameter MUST
   be included in the sidebyValRequest message.  In this case, the
   "confObjID" parameter contains the XCON-URI of the main conference in
   which the sidebar has to be created.  If no "sidebarByValInfo"
   parameter is included, as envisaged in the XCON framework
   ([RFC5239]), the sidebar is created by cloning the main conference,
   following the implementation specific cloning rules.  Otherwise,
   similarly to the case of direct creation, the sidebar conference
   object is built on the basis of the "sidebarByValInfo" parameter
   provided by the requestor.  As a consequence of a sidebar-by-val
   creation, the conference server MUST update the main conference
   object reflected by the "confObjID" parameter in the
   sidebarbyValRequest/create message introducing the new sidebar object
   as a new new <entry> in the proper section <sidebars-by-val>.  The
   newly created sidebar conference object MAY be included in the
   sidebarByValResponse in the "sidebarByValInfo" parameter, if the
   "response-code" is "success".  The XCON-URI of the newly created
   sidebar MUST appear in the "confObjID" parameter of the response.
   The conference server can notify any conferencing clients that have
   subscribed to the conference event package, and are authorized to
   receive the notifications, of the addition of the sidebar to the
   conference.

   In the case of a "sidebarByVal" request with an operation of
   "retrieve", the URI for the conference object created for the sidebar
   (received in the response to a "create" operation or in a
   sidebarsByValResponse message) MUST be included in the "confObjID"
   parameter in the request.  This "retrieve" operation is handled by
   the conference server in the same manner as a "retrieve" operation
   included in a confRequest message as detailed in Section 6.3.4.



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   In the case of a "sidebarByVal" request with an operation of
   "update", the "sidebarByValInfo" MUST also be included in the
   request.  The "confObjID" parameter contained in the request message
   identifies the specific sidebar instance to be updated.  An "update"
   operation on the "sidebarByValInfo" is handled by the conference
   server in the same manner as an "update" operation on the confInfo
   included in a confRequest message as detailed in Section 6.3.4.  A
   "sidebarByValResponse" message MUST carry back to the client a
   "version" element related to the current version of the sidebar whose
   identifier is contained in the "confObjId" field of the request.

   If an "operation" of "delete" is included in the sidebarByVal
   request, the "sidebarByValInfo" parameter MUST NOT be included in the
   request.  Any "sidebarByValInfo" included in the request MUST be
   ignored by the conference server.  The URI for the conference object
   associated with the sidebar MUST be included in the "confObjID"
   parameter in the request.  If the specific conferencing user as
   reflected by the "confUserID" in the request is authorized to delete
   the conference, the conference server deletes the conference object
   reflected by the "confObjID" parameter and updates the data in the
   conference object from which the sidebar was cloned.  The conference
   server can notify any conferencing clients that have subscribed to
   the conference event package, and are authorized to receive the
   notifications, of the deletion of the sidebar to the conference.

   If a sidebarByValRequest with an "operation" of "retrieve", "update"
   or "delete" carries a "confObjID" which is not associated with any
   existing sidebar-by-val, a confResponse message containing an
   "objectNotFound" error code will be generated on the server's side.
   This holds also for the case in which the mentioned "confObjID" is
   related to an existing conference object stored at the server, but
   associated with a blueprint or with an actual conference or with a
   sidebar-by-ref rather than a sidebar-by-val.



   <!-- sidebarByValRequest -->

   <xs:complexType name="ccmp-sidebarByVal-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="sidebarByValRequest"/>
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>




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   <!-- sidebarByValRequestType -->

   <xs:element name="sidebarByValRequest"
               type="sidebarByValRequestType" />

   <xs:complexType name="sidebarByValRequestType">
       <xs:sequence>
           <xs:element name="sidebarByValInfo"
                       type="info:conference-type" minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>


   <!-- sidebarByValResponse -->

   <xs:complexType name="ccmp-sidebarByVal-response-message-type">
    <xs:complexContent>
           <xs:extension base="tns:ccmp-response-message-type">
            <xs:sequence>
                   <xs:element ref="sidebarByValResponse"/>
            </xs:sequence>
     </xs:extension>
    </xs:complexContent>
   </xs:complexType>

   <!-- sidebarByValResponseType -->

   <xs:element name="sidebarByValResponse"
               type="sidebarByValResponseType" />

   <xs:complexType name="sidebarByValResponseType">
     <xs:sequence>
        <xs:element name="sidebarByValInfo"
                    type="info:conference-type minOccurs="0"/>
        <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>


            Figure 14: Structure of the sidebarByValRequest and
                       sidebarByValResponse messages





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6.3.9.  sidebarsByRefRequest and sidebarsByRefResponse

   Similar to the sidebarsByValRequest, a sidebarsByRefRequest can be
   invoked to retrieve the <sidebars-by-ref> element of the conference
   object identified by the "confObjID" parameter.  The
   "sidebarsByRefRequest" message is of a "retrieve-only" type, so an
   "operation" parameter MUST NOT be included in a
   "sidebarsByRefRequest" message.  In the case of a "response-code" of
   "success", the "sidebarsByRefInfo" parameter, containing the
   <sidebars-by-ref> element of the conference object, MUST be included
   in the response.  The <sidebars-by-ref> element represents the set of
   URIs of the sidebars associated with the main conference, whose
   description (in the form of a standard XCON conference document) is
   external to the main conference itself.  Through the retrieved URIs,
   it is then possible to access single sidebars using the
   "sidebarByRef" request message, described in Section 6.3.10.  A
   "sidebarsByRefResponse" message MUST carry back to the client a
   "version" element related to the current version of the main
   conference object (i.e. the one whose identifier is contained in the
   "confObjId" field of the request) to which the sidebars in question
   are associated.



 <!-- sidebarsByRefRequest -->

 <xs:complexType name="ccmp-sidebarsByRef-request-message-type">
     <xs:complexContent>
         <xs:extension base="tns:ccmp-request-message-type">
             <xs:sequence>
                 <xs:element ref="sidebarsByRefRequest"/>
             </xs:sequence>
         </xs:extension>
    </xs:complexContent>
 </xs:complexType>

 <!-- sidebarsByRefRequestType -->

 <xs:element name="sidebarsByRefRequest"
             type="sidebarsByRefRequestType" />

 <xs:complexType name="sidebarsByRefRequestType">
     <xs:sequence>
         <xs:element name="xpathFilter" type="xs:string" minOccurs="0"/>
         <xs:any namespace="##other" processContents="lax"
                 minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:anyAttribute namespace="##any" processContents="lax"/>



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 </xs:complexType>


 <!-- sidebarsByRefResponse -->

 <xs:complexType name="ccmp-sidebarsByref-response-message-type">
         <xs:complexContent>
          <xs:extension base="tns:ccmp-response-message-type">
                  <xs:sequence>
                         <xs:element ref="sidebarsByRefResponse"/>
                  </xs:sequence>
          </xs:extension>
   </xs:complexContent>
 </xs:complexType>

 <!-- sidebarsByRefResponseType -->

 <xs:element name="sidebarsByRefResponse"
             type="sidebarsByRefResponseType" />

 <xs:complexType name="sidebarsByRefResponseType">
     <xs:sequence>
        <xs:element name="sidebarsByRefInfo"
                    type="info:uris-type" minOccurs="0"/>
        <xs:any namespace="##other" processContents="lax"
                minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:anyAttribute namespace="##any" processContents="lax"/>
 </xs:complexType>


           Figure 15: Structure of the sidebarsByRefRequest and
                      sidebarsByRefResponse messages

6.3.10.  sidebarByRefRequest and sidebarByRefResponse

   A sidebarByRefRequest message MUST contain the "operation" parameter
   which discriminates among retrieval, creation, modification and
   deletion of a specific sidebar.  The other required parameters depend
   upon the type of operation.

   In the case of a "create" operation, the "confObjID" parameter MUST
   be included in the sidebyRefRequest message.  In this case, the
   "confObjID" parameter contains the XCON-URI of the main conference in
   which the sidebar has to be created.  If no "sidebarByRefInfo"
   parameter is included, as envisaged in the XCON framework
   ([RFC5239]), the sidebar is created by cloning the main conference,
   following the implementation specific cloning rules.  Otherwise,



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   similarly to the case of direct creation, the sidebar conference
   object is built on the basis of the "sidebarByRefInfo" parameter
   provided by the requestor.  If the creation of the sidebar is
   successful, the conference server MUST update the "sidebars-by-ref"
   element in the conference object from which the sidebar was created
   (i.e., as identified by the "confObjID" in the original sidebarByRef
   request), with the URI of the newly created sidebar.  The newly
   created conference object MAY be included in the response in the
   "sidebarByRefInfo" parameter with a "response-code" of "success".
   The URI for the conference object associated with the newly created
   sidebar object MUST appear in the "confObjID" parameter of the
   response.  The conference server can notify any conferencing clients
   that have subscribed to the conference event package, and are
   authorized to receive the notifications, of the addition of the
   sidebar to the conference.

   In the case of a "sidebarByRef" request with an operation of
   "retrieve", the URI for the conference object created for the sidebar
   MUST be included in the "confObjID" parameter in the request.  A
   "retrieve" operation on the "sidebarByRefInfo" is handled by the
   conference server in the same manner as a "retrieve" operation on the
   confInfo included in a confRequest message as detailed in
   Section 6.3.4.

   In the case of a "sidebarByRef" request with an operation of
   "update", the URI for the conference object created for the sidebar
   MUST be included in the "confObjID" parameter in the request.  The
   "sidebarByRefInfo" MUST also be included in the request in the case
   of an "operation" of "update".  An "update" operation on the
   "sidebarByRefInfo" is handled by the conference server in the same
   manner as an "update" operation on the confInfo included in a
   confRequest message as detailed in Section 6.3.4.  A
   "sidebarByRefResponse" message MUST carry back to the client a
   "version" element related to the current version of the sidebar whose
   identifier is contained in the "confObjId" field of the request.

   If an "operation" of "delete" is included in the sidebarByRef
   request, the "sidebarByRefInfo" parameter MUST NOT be included in the
   request.  Any "sidebarByRefInfo" included in the request MUST be
   ignored by the conference server.  The URI for the conference object
   for the sidebar MUST be included in the "confObjID" parameter in the
   request.  If the specific conferencing user as reflected by the
   "confUserID" in the request is authorized to delete the conference,
   the conference server SHOULD delete the conference object reflected
   by the "confObjID" parameter and SHOULD update the "sidebars-by-ref"
   element in the conference object from which the sidebar was
   originally cloned.  The conference server can notify any conferencing
   clients that have subscribed to the conference event package, and are



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   authorized to receive the notifications, of the deletion of the
   sidebar.

   If a sidebarByRefRequest with an "operation" of "retrieve", "update"
   or "delete" carries a "confObjID" which is not associated with any
   existing sidebar-by-ref, a confResponse message containing an
   "objectNotFound" error code will be generated on the server's side.
   This holds also for the case in which the mentioned "confObjID" is
   related to an existing conference object stored at the server, but
   associated with a blueprint or with an actual conference or with a
   sidebar-by-val rather than a sidebar-by-ref.



   <!-- sidebarByRefRequest -->

   <xs:complexType name="ccmp-sidebarByRef-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="sidebarByRefRequest"/>
                </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- sidebarByRefRequestType -->

   <xs:element name="sidebarByRefRequest"
               type="sidebarByRefRequestType" />

   <xs:complexType name="sidebarByRefRequestType">
       <xs:sequence>
           <xs:element name="sidebarByRefInfo"
                       type="info:conference-type" minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                  minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!-- sidebarByRefResponse -->

   <xs:complexType name="ccmp-sidebarByRef-response-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-response-message-type">
               <xs:sequence>
                   <xs:element ref="sidebarByRefResponse"/>



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               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- sidebarByRefResponseType -->

   <xs:element name="sidebarByRefResponse"
               type="sidebarByRefResponseType" />

   <xs:complexType name="sidebarByRefResponseType">
       <xs:sequence>
           <xs:element name="sidebarByRefInfo"
                       type="info:conference-type" minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                  minOccurs="0" maxOccurs="unbounded"/>
     </xs:sequence>
     <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>


            Figure 16: Structure of the sidebarByRefRequest and
                       sidebarByRefResponse messages

6.4.  CCMP Response Codes

   All CCMP response messages MUST include a ""response-code"".  The
   following summarizes the CCMP response codes:

   success:  Successful completion of the requested operation.

   badRequest:  Syntactically malformed request.

   objectNotFound:  Target conference object missing at the server (it
      refers to the "confObjID" parameter in the generic request
      message)

   userNotFound:  Target user missing at the server (it is related to
      the XCON-USERID in the "entity" attribute of the "userInfo"
      parameter when it is included in userRequests)

   invalidConfUserID:  User missing at the server (this code is returned
      in the case of requests in which the "confUserID" of the sender is
      invalid).







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   invalidConfPassword:  Target conference object's password contained
      in the request is wrong.

   confPasswordRequired:  "conference-password" missing in a request to
      access a password-protected conference object.

   unauthorized:  User not allowed to perform the required operation.

   authenticationRequired:  User's authentication information missing in
      a request to perform the requested operation. "subject" parameter
      needed in the request.

   forbidden:  Operation not allowed (e.g., cancellation of a
      blueprint).

   forbiddenDeleteParent:  Cancel operation failed since the target
      object is a parent of child objects which depend on it, or because
      it effects, based on the "parent-enforceable" mechanism, the
      corresponding element in a child object.

   forbiddenChangeProtected:  Update refused by the server because the
      target element cannot be modified due to its implicit dependence
      on the value of a parent object ("parent-enforceable" mechanism).

   requestTimeout:  The time required to serve the request has exceeded
      the envisaged service threshold.

   serverInternalError:  The server cannot complete the required service
      due to a system internal error.

   notImplemented:  Operation envisaged in the protocol, but not
      implemented in the contacted server.

   updateFailed  A generic error associated with all those situations in
      which a requested "update" cannot be successfully completed by the
      server.  An example of such situation is when the modification of
      an object cannot be applied due to conflicts arising at the
      server's side (e.g. because the client version of the object is an
      obsolete one and the requested modifications collide with the up-
      to-date state of the object stored at the server).

   The handling of a "response-code" of "objectNotFound",
   "userNotFound", "deleteParentFailed" and "forbiddenChangeProtected"
   are only applicable to specific operations for specialized message
   responses and the details are provided in Section 6.3.  The following
   table summarizes these response codes and the specialized message and
   operation to which they are applicable:




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   +---------------+------------+------------+------------+------------+
   | Response code | Create     | Retrieve   | Update     | Delete     |
   +---------------+------------+------------+------------+------------+
   | updateFailed  | N/A        | N/A        | All update | N/A        |
   |               |            |            | requests   |            |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | objectNotFoun | userReques | All        | All update | All delete |
   | d             | t,         | retrieve   | requests   | requests   |
   |               |  sidebarBy | requests,  |            |            |
   |               | ValRequest | EXCEPT:    |            |            |
   |               |   sidebars | blueprints |            |            |
   |               | ByRefReque | Request,   |            |            |
   |               | st         |  confsRequ |            |            |
   |               |            | est        |            |            |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | userNotFound  | userReques | userReques | userReques | userReques |
   |               | t(3rd part | t          | t          | t          |
   |               | yinvite    |            |            |            |
   |               |  with thir |            |            |            |
   |               | duser      |            |            |            |
   |               |  entity)   |            |            |            |
   |               |  (*)       |            |            |            |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | invalidConfUs | All create | All        | All update | All delete |
   | erID          | requests,  | retrieve   | requests   | requests   |
   |               | EXCEPT:    | requests   |            |            |
   |               | userReques |            |            |            |
   |               | twith no   |            |            |            |
   |               |  confUserI |            |            |            |
   |               | D(**)      |            |            |            |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | forbiddenDele | N/A        | N/A        | N/A        | All delete |
   | teParent      |            |            |            | request    |
   |               |            |            |            |            |
   | ------------- | ---------- | ---------- | ---------- | ---------- |
   |               |            |            |            |            |
   | forbiddenChan | N/A        | N/A        | All update | N/A        |
   | geProtected   |            |            | requests   |            |
   +---------------+------------+------------+------------+------------+




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             Table 2: Response codes and associated operations

   (*) "userNotFound" in answer to a "userRequest/create" operation: in
   the case of a third-party invite, this code can be returned if the
   "confUserID" (contained in the "entity" attribute of the "userInfo"
   parameter) of the user to be added is unknown.  In the case above, if
   instead it is the "confUserID" of the sender of the request that is
   invalid, an "invalidConfUserID" error code is returned to the client.

   (**) "invalidConfUserID" is not sent in answers to "userRequest/
   create" messages having a "null" confUserID, since this case is
   associated with a user who is unaware of his own XCON-USERID, but
   wants to enter a known conference.

   In the case of a response code of "requestTimeout", a conferencing
   client MAY re-attempt the request within a period of time that would
   be specific to a conference control client or conference control
   server.

   A response code of "badRequest" indicates that the conference control
   client sent a malformed request, which is indicative of an error in
   the conference control client or in the conference control server.
   The handling is specific to the conference control client
   implementation (e.g., generate a log, display an error message,
   etc.).  It is NOT RECOMMENDED that the client re-attempt the request
   in this case.

   Response codes such as "unauthorized" and "forbidden" indicate the
   client does not have the appropriate permissions, or there is an
   error in the permissions: re-attempting the request would likely not
   succeed and thus it is NOT RECOMMENDED.

   Any unexpected or unknown "response-code" SHOULD be treated by the
   client in the same manner as a "serverInternalError" "response-code",
   the handling of which is specific to the conference control client
   implementation.















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7.  A complete example of the CCMP in action

   In this section a typical scenario in which the CCMP comes into play
   is described, by showing the actual composition of the various CCMP
   messages.  In the call flows of the example, the Conference Control
   Client is a CCMP-enabled client, whereas the Conference Control
   Server is a CCMP-enabled server.  The "confUserID" of the client,
   Alice, is "xcon-userid:Alice@example.com" and appears in all
   requests.  The sequence of operations is as follows:

   1.  Alice retrieves from the server the list of available blueprints
       (Section 7.1);

   2.  Alice asks for detailed information about a specific blueprint
       (Section 7.2);

   3.  Alice decides to create a new conference by cloning the retrieved
       blueprint (Section 7.3);

   4.  Alice modifies information (e.g.  XCON-URI, name, description)
       associated with the newly created blueprint (Section 7.4);

   5.  Alice specifies a list of users to be contacted when the
       conference is activated (Section 7.5);

   6.  Alice joins the conference (Section 7.6);

   7.  Alice lets a new user, Ciccio, (whose "confUserID" is
       "xcon-userid:Ciccio@example.com") join the conference
       (Section 7.7).

   Note, the examples do not include any details beyond the basic
   operation.

   In the following sections we deal with each of the above mentioned
   actions separately.

7.1.  Alice retrieves the available blueprints

   This section illustrates the transaction associated with retrieval of
   the blueprints, together with a dump of the two messages exchanged
   ("blueprintsRequest" and "blueprintsResponse").  As it comes out from
   the figure, the "blueprintsResponse" message contains, in the
   "blueprintsInfo" parameter, information about the available
   blueprints, in the form of the standard XCON-URI of the blueprint,
   plus additional (and optional) information, like its display-text and
   purpose.




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   Alice retrieves from the server the list of available blueprints:




     CCMP Client                                             CCMP Server
          |                                                       |
          | CCMP blueprintsRequest message                        |
          |   - confUserID: Alice                                 |
          |   - confObjID: (null)                                 |
          |------------------------------------------------------>|
          |                                                       |
          |                     CMP blueprintsResponse message    |
          |                      - confUserID: Alice              |
          |                      - confObjID: (null)              |
          |                      - response-code: success         |
          |                      - blueprintsInfo: bp123,bp124,.. |
          |<------------------------------------------------------|
          |                                                       |
          .                                                       .
          .                                                       .

   1. blueprintsRequest message:

   <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <ccmp:ccmpRequest xmlns:info="urn:ietf:params:xml:ns:conference-info"
     xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp"
     xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info">
    <ccmpRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="xcon:ccmp-blueprints-request-message-type">
       <confUserID>xcon-userid:Alice@example.com</confUserID>
    </ccmpRequest>
   </ccmp:ccmpRequest>

   2. blueprintsResponse message form the server:

   <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <ccmp:ccmpResponse
    xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info"
    xmlns:info="urn:ietf:params:xml:ns:conference-info"
    xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp">
   <ccmpResponse
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:type="ccmp:ccmp-blueprints-response-message-type">
      <confUserID>xcon-userid:Alice@example.com</confUserID>
       <ccmp:response-code>success</ccmp:response-code>
        <ccmp:blueprintsResponse>
         <blueprintsInfo>



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          <info:entry>
           <info:uri>xcon:AudioRoom@example.com</info:uri>
           <info:display-text>AudioRoom</info:display-text>
           <info:purpose>Simple Room:
              conference room with public access,
              where only audio is available, more users
              can talk at the same time
              and the requests for the AudioFloor
              are automatically accepted.
           </info:purpose>
          </info:entry>
          <info:entry>
           <info:uri>xcon:VideoRoom@example.com</info:uri>
           <info:display-text>VideoRoom</info:display-text>
           <info:purpose>Video Room:
               conference room with public access,
               where both audio and video are available,
               8 users can talk and be seen at the same time,
               and the floor requests are automatically accepted.
           </info:purpose>
          </info:entry>
          <info:entry>
           <info:uri>xcon:AudioConference1@example.com</info:uri>
           <info:display-text>AudioConference1</info:display-text>
           <info:purpose>Public Audio Conference:
                conference with public access,
                where only audio is available,
                only one user can talk at the same time,
                and the requests for the AudioFloor MUST
                be accepted by a Chair.
           </info:purpose>
          </info:entry>
          <info:entry>
           <info:uri>xcon:VideoConference1@example.com</info:uri>
           <info:display-text>VideoConference1</info:display-text>
             <info:purpose>Public Video Conference: conference
                 where both audio and video are available,
                 only one user can talk
             </info:purpose>
           </info:entry>
           <info:entry>
            <info:uri>xcon:AudioConference2@example.com</info:uri>
            <info:display-text>AudioConference2</info:display-text>
            <info:purpose>Basic Audio Conference:
                 conference with private access,
                 where only audio is available,
                 only one user can talk at the same time,
                 and the requests for the AudioFloor MUST



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                 be accepted by a Chair.
            </info:purpose>
           </info:entry>
        </blueprintsInfo>
      </ccmp:blueprintsResponse>
     </ccmpResponse>
   </ccmp:ccmpResponse>



               Figure 17: Getting blueprints from the server

7.2.  Alice gets detailed information about a specific blueprint

   This section illustrates the second transaction in the overall flow.
   In this case, Alice, who now knows the XCON-URIs of the blueprints
   available at the server, makes a drill-down query, in the form of a
   CCMP "blueprintRequest" message, to get detailed information about
   one of them (the one called with XCON-URI
   "xcon:AudioRoom@example.com").  The picture shows such transaction.
   Notice that the response contains, in the "blueprintInfo" parameter,
   a document compliant with the standard XCON data model.

   Alice retrieves detailed information about a specified blueprint:




     CCMP Client                                             CCMP Server
          |                                                       |
          | CCMP blueprintRequest message                         |
          |   - confUserID: Alice                                 |
          |   - confObjID: bp123                                  |
          |   - operation: retrieve                               |
          |   - blueprintInfo: (null)                             |
          |------------------------------------------------------>|
          |                                                       |
          |                        CCMP blueprintResponse message |
          |                          - confUserID: Alice          |
          |                          - confObjID: bp123           |
          |                          - operation: retrieve        |
          |                          - response-code: success     |
          |                          - blueprintInfo: bp123Info   |
          |<------------------------------------------------------|
          |                                                       |
          .                                                       .
          .                                                       .




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   1. blueprintRequest message:

   <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <ccmp:ccmpRequest
         xmlns:info="urn:ietf:params:xml:ns:conference-info"
         xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp"
         xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info">
     <ccmpRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                    xsi:type="ccmp:ccmp-blueprint-request-message-type">
           <confUserID>xcon-userid:Alice@example.com</confUserID>
           <confObjID>xcon:AudioRoom@example.com</confObjID>
           <operation>retrieve</operation>
           <ccmp:blueprintRequest/>
     </ccmpRequest>
   </ccmp:ccmpRequest>

   2. blueprintResponse message form the server:

   <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <ccmp:ccmpResponse
         xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info"
         xmlns:info="urn:ietf:params:xml:ns:conference-info"
         xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp">
     <ccmpResponse xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                 xsi:type="ccmp:ccmp-blueprint-response-message-type">
       <confUserID>xcon-userid:Alice@example.com</confUserID>
       <confObjID>xcon:AudioRoom@example.com</confObjID>
       <operation>retrieve</operation>
       <ccmp:response-code>success</ccmp:response-code>
       <ccmp:blueprintResponse>
         <blueprintInfo entity="xcon:AudioRoom@example.com">
           <info:conference-description>
              <info:display-text>AudioRoom</info:display-text>
              <info:maximum-user-count>2</info:maximum-user-count>
              <info:available-media>
                <info:entry label="audioLabel">
                    <info:type>audio</info:type>
                </info:entry>
                </info:available-media>
           </info:conference-description>
           <info:users>
              <xcon:join-handling>allow</xcon:join-handling>
           </info:users>
           <xcon:floor-information>
             <xcon:floor-request-handling>confirm
             </xcon:floor-request-handling>
             <xcon:conference-floor-policy>
                   <xcon:floor id="audioLabel"></xcon:floor>



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             </xcon:conference-floor-policy>
           </xcon:floor-information>
         </blueprintInfo>
       </ccmp:blueprintResponse>
     </ccmpResponse>
   </ccmp:ccmpResponse>



            Figure 18: Getting info about a specific blueprint

7.3.  Alice creates a new conference through a cloning operation

   This section illustrates the third transaction in the overall flow.
   Alice decides to create a new conference by cloning the blueprint
   having XCON-URI "xcon:AudioRoom@example.com", for which she just
   retrieved detailed information through the "blueprintRequest"
   message.  This is achieved by sending a "confRequest/create" message
   having the blueprint's URI in the "confObjID" parameter.  The picture
   shows such transaction.  Notice that the response contains, in the
   "confInfo" parameter, the document associated with the newly created
   conference, which is compliant with the standard XCON data model.
   The "confObjID" in the response is set to the XCON-URI of the new
   conference (in this case, "xcon:8977794@example.com").  We also
   notice that this value is equal to the value of the "entity"
   attribute of the <conference-info> element of the document
   representing the newly created conference object.

   Alice creates a new conference by cloning the
   "xcon:AudioRoom@example.com" blueprint:




  CCMP Client                                             CCMP Server
         |                                                       |
         | CCMP confRequest message                              |
         |   - confUserID: Alice                                 |
         |   - confObjID: AudioRoom                              |
         |   - operation: create                                 |
         |   - confInfo: (null)                                  |
         |------------------------------------------------------>|
         |                                                       |
         |                            CCMP confResponse message  |
         |                              - confUserID: Alice      |
         |                              - confObjID: newConfId   |
         |                              - operation: create      |
         |                              - response-code: success |



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         |                              - version: 1             |
         |                              - confInfo: newConfInfo  |
         |<------------------------------------------------------|
         |                                                       |
         .                                                       .
         .                                                       .

  1. confRequest message:

  <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
  <ccmp:ccmpRequest
        xmlns:info="urn:ietf:params:xml:ns:conference-info"
        xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp"
        xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info">
     <ccmpRequest
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:type="ccmp:ccmp-conf-request-message-type">
        <confUserID>xcon-userid:Alice@example.com</confUserID>
        <confObjID>xcon:AudioRoom@example.com</confObjID>
        <operation>create</operation>
        <ccmp:confRequest/>
     </ccmpRequest>
  </ccmp:ccmpRequest>


  2. confResponse message from the server:

  <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
  <ccmp:ccmpResponse
       xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info"
       xmlns:info="urn:ietf:params:xml:ns:conference-info"
       xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp">
    <ccmpResponse
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:type="ccmp:ccmp-conf-response-message-type">
       <confUserID>xcon-userid:Alice@example.com</confUserID>
       <confObjID>xcon:8977794@example.com</confObjID>
           <operation>create</operation>
       <ccmp:response-code>success</ccmp:response-code>
       <ccmp:version>1</ccmp:version>
       <ccmp:confResponse>
            <confInfo entity="xcon:8977794@example.com">
              <info:conference-description>
                  <info:display-text>
                     New conference by Alice cloned from AudioRoom
                  </info:display-text>
                  <info:conf-uris>
                     <info:entry>



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                        <info:uri>
                            xcon:8977794@example.com
                        </info:uri>
                        <info:display-text>
                            conference xcon-uri
                        </info:display-text>
                        <xcon:conference-password>
                            8601
                        </xcon:conference-password>
                      </info:entry>
                   </info:conf-uris>
                   <info:maximum-user-count>10</info:maximum-user-count>
                   <info:available-media>
                          <info:entry label="11">
                              <info:type>audio</info:type>
                          </info:entry>
                   </info:available-media>
               </info:conference-description>
               <info:users>
                   <xcon:join-handling>allow</xcon:join-handling>
               </info:users>
                  <xcon:floor-information>
                     <xcon:floor-request-handling>
                        confirm</xcon:floor-request-handling>
                     <xcon:conference-floor-policy>
                       <xcon:floor id="11"/>
                     </xcon:conference-floor-policy>
                  </xcon:floor-information>
              </confInfo>
          </ccmp:confResponse>
      </ccmpResponse>
  </ccmp:ccmpResponse>




        Figure 19: Creating a new conference by cloning a blueprint

7.4.  Alice updates conference information

   This section illustrates the fourth transaction in the overall flow.
   Alice decides to modify some of the details associated with the
   conference she just created.  More precisely, she changes the
   <display-text> element under the <conference-description> element of
   the document representing the conference.  This is achieved through a
   "confRequest/update" message carrying the fragment of the conference
   document to which the required changes have to be applied.  As shown
   in the picture, the response contains a code of "success", which



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   acknowledges the modifications requested by the client, while also
   updating the conference version number from 1 to 2, as reflected in
   the "version" parameter.

   Alice updates information about the conference she just created:




     CCMP Client                                             CCMP Server
          |                                                       |
          | CCMP confRequest message                              |
          |   - confUserID: Alice                                 |
          |   - confObjID: 8977794                                |
          |   - operation: update                                 |
          |   - confInfo: confUpdates                             |
          |------------------------------------------------------>|
          |                                                       |
          |                            CCMP confResponse message  |
          |                              - confUserID: Alice      |
          |                              - confObjID: 8977794     |
          |                              - operation: update      |
          |                              - response-code: success |
          |                              - version: 2             |
          |                              - confInfo: (null)       |
          |<------------------------------------------------------|
          |                                                       |
          .                                                       .
          .                                                       .


   1. confRequest message:

   <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <ccmp:ccmpRequest
        xmlns:info="urn:ietf:params:xml:ns:conference-info"
              xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp"
        xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info">
     <ccmpRequest
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:type="ccmp:ccmp-conf-request-message-type">
       <confUserID>xcon-userid:Alice@example.com</confUserID>
       <confObjID>xcon:8977794@example.com</confObjID>
       <operation>update</operation>
       <ccmp:confRequest>
            <confInfo entity="xcon:8977794@example.com">
               <info:conference-description>
                 <info:display-text>



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                    Alice's conference
                 </info:display-text>
               </info:conference-description>
            </confInfo>
         </ccmp:confRequest>
     </ccmpRequest>
   </ccmp:ccmpRequest>


   2. confResponse message form the server:

   <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <ccmp:ccmpResponse
       xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info"
       xmlns:info="urn:ietf:params:xml:ns:conference-info"
             xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp">
     <ccmpResponse xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                  xsi:type="ccmp:ccmp-conf-response-message-type">
        <confUserID>xcon-userid:Alice@example.com</confUserID>
        <confObjID>xcon:8977794@example.com</confObjID>
            <operation>update</operation>
        <ccmp:response-code>success</ccmp:response-code>
        <ccmp:version>2</ccmp:version>
        <ccmp:confResponse/>
     </ccmpResponse>
   </ccmp:ccmpResponse>



                Figure 20: Updating conference information

7.5.  Alice inserts a list of users in the conference object

   This section illustrates the fifth transaction in the overall flow.
   Alice modifies the <allowed-users-list> under the <users> element in
   the document associated with the conference she created.  To the
   purpose, she exploits the "usersRequest" message provided by the
   CCMP.  The picture below shows the transaction.

   Alice updates information about the list of users to whom access to
   the conference is permitted:



   CCMP Client                                             CCMP Server
        |                                                       |
        | CCMP usersRequest message                             |
        |   - confUserID: Alice                                 |



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        |   - confObjID: 8977794                                |
        |   - operation: update                                 |
        |   - usersInfo: usersUpdates                           |
        |------------------------------------------------------>|
        |                                                       |
        |                           CCMP usersResponse message  |
        |                             - confUserID: Alice       |
        |                             - confObjID: 8977794      |
        |                             - operation: update       |
        |                             - response-code: success  |
        |                             - version: 3              |
        |                             - usersInfo: (null)       |
        |<------------------------------------------------------|
        |                                                       |
        .                                                       .
        .                                                       .

 1. usersRequest message:

 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
 <ccmp:ccmpRequest
      xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info"
            xmlns:info="urn:ietf:params:xml:ns:conference-info"
            xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp">
     <ccmpRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                  xsi:type="ccmp:ccmp-users-request-message-type">
         <confUserID>xcon-userid:Alice@example.com</confUserID>
         <confObjID>xcon:8977794@example.com</confObjID>
         <operation>update</operation>
         <ccmp:usersRequest>
             <usersInfo>
                 <xcon:allowed-users-list>
                     <xcon:target method="dial out"
                                  uri="xmpp:cicciolo@pippozzo.com"/>
                     <xcon:target method="refer"
                                  uri="tel:+390817683823"/>
                     <xcon:target method="refer"
                                  uri="sip:Carol@example.com"/>
                 </xcon:allowed-users-list>
             </usersInfo>
         </ccmp:usersRequest>
     </ccmpRequest>
 </ccmp:ccmpRequest>


 2. usersResponse message form the server:

 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>



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 <ccmp:ccmpResponse
       xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info"
                   xmlns:info="urn:ietf:params:xml:ns:conference-info"
                         xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp">
     <ccmpResponse xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                   xsi:type="ccmp:ccmp-conf-response-message-type">
         <confUserID>xcon-userid:Alice@example.com</confUserID>
         <confObjID>xcon:8977794@example.com</confObjID>
                 <operation>update</operation>
         <ccmp:response-code>success</ccmp:response-code>
         <ccmp:version>3</ccmp:version>
         <ccmp:confResponse/>
     </ccmpResponse>
 </ccmp:ccmpResponse>



     Figure 21: Updating the list of allowed users for the conference
                        'xcon:8977794@example.com'

7.6.  Alice joins the conference

   This section illustrates the sixth transaction in the overall flow.
   Alice uses the CCMP to add herself to the newly created conference.
   This is achieved through a "userRequest/create" message containing,
   in the "userInfo" parameter, a <user> element compliant with the XCON
   data model representation.  Notice that such element includes
   information about the user's Address of Records, as well as her
   current end-point.  The picture below shows the transaction.  Notice
   how the "confUserID" parameter is equal to the "entity" attribute of
   the <userInfo> element, which indicates that the request issued by
   the client is a first-party one.

   Alice joins the conference by issuing a "userRequest/create" message
   with her own id to the server:



    CCMP Client                                             CCMP Server
         |                                                       |
         | CCMP userRequest message                              |
         |   - confUserID: Alice                                 |
         |   - confObjID: 8977794                                |
         |   - operation: create                                 |
         |   - userInfo: AliceUserInfo                           |
         |------------------------------------------------------>|
         |                                                       |
         |                            CCMP userResponse message  |



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         |                              - confUserID: Alice      |
         |                              - confObjID: 8977794     |
         |                              - operation: create      |
         |                              - response-code: success |
         |                              - version: 4             |
         |                              - userInfo: (null)       |
         |<------------------------------------------------------|
         |                                                       |
         .                                                       .
         .                                                       .

  1. userRequest message:

  <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
  <ccmp:ccmpRequest
       xmlns:info="urn:ietf:params:xml:ns:conference-info"
             xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp"
             xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info">
      <ccmpRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
              xsi:type="ccmp:ccmp-user-request-message-type">
          <confUserID>xcon-userid:Alice@example.com</confUserID>
          <confObjID>xcon:8977794@example.com</confObjID>
                  <operation>create</operation>
          <ccmp:userRequest>
              <userInfo entity="xcon-userid:Alice@example.com">
                  <info:associated-aors>
                      <info:entry>
                          <info:uri>
                             mailto:Alice83@example.com
                          </info:uri>
                          <info:display-text>email</info:display-text>
                      </info:entry>
                  </info:associated-aors>
                  <info:endpoint entity="sip:alice_789@example.com"/>
              </userInfo>
          </ccmp:userRequest>
      </ccmpRequest>
  </ccmp:ccmpRequest>


  2. userResponse message form the server:

  <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
  <ccmp:ccmpResponse
      xmlns:info="urn:ietf:params:xml:ns:conference-info"
      xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp"
      xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info">
     <ccmpResponse xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"



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                    xsi:type="ccmp:ccmp-user-response-message-type">
          <confUserID>xcon-userid:Alice@example.com</confUserID>
          <confObjID>xcon:8977794@example.com</confObjID>
          <operation>create</operation>
          <ccmp:response-code>success</ccmp:response-code>
          <ccmp:version>4</ccmp:version>
          <ccmp:userResponse/>
      </ccmpResponse>
  </ccmp:ccmpResponse>



          Figure 22: Alice joins the conference through the CCMP

7.7.  Alice adds a new user to the conference

   This section illustrates the seventh and last transaction in the
   overall flow.  Alice uses the CCMP to add a new conferencing system
   user, Ciccio, to the conference.  This "third-party" request is
   realized through a "userRequest/create" message containing, in the
   "userInfo" parameter, a <user> element compliant with the XCON data
   model representation.  Notice that such element includes information
   about Ciccio's Address of Records, as well as his current end-point,
   but has a fake "entity" attribute, since it is unknown to Alice, in
   this example.  Thus, the server is in charge of generating a new
   XCON-USERID for the user Alice indicates, and returning it in the
   "entity" attribute of the "userInfo" parameter carried in the
   response, as well as adding the user to the conference.  The picture
   below shows the transaction.

   Alice adds user "Ciccio" to the conference by issuing a third-party
   "userRequest/create" message to the server:



   CCMP Client                                             CCMP Server
        |                                                       |
        | CCMP userRequest message                              |
        |   - confUserID: Alice                                 |
        |   - confObjID: 8977794                                |
        |   - operation: create                                 |
        |   - userInfo: CiccioUserInfo(with dummy "entity")     |
        |------------------------------------------------------>|
        |                                                       |
        |                          CCMP userResponse message    |
        |                            - confUserID: Alice        |
        |                            - confObjID: 8977794       |
        |                            - operation: create        |



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        |                            - response-code: success   |
        |                            - version: 5               |
        |                            - userInfo: CiccioUserInfo |
        |                                (with actual "entity") |
        |<------------------------------------------------------|
        |                                                       |
        .                                                       .
        .                                                       .

 1. "third party" userRequest message from Alice:

 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
 <ccmp:ccmpRequest
        xmlns:info="urn:ietf:params:xml:ns:conference-info"
        xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp"
        xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info">
     <ccmpRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                  xsi:type="ccmp:ccmp-user-request-message-type">
         <confUserID>xcon-userid:Alice@example.com</confUserID>
         <confObjID>xcon:8977794@example.com</confObjID>
         <operation>create</operation>
         <ccmp:userRequest>
             <userInfo entity="xcon-userid:AUTO_GENERATE@example.com">
                 <info:associated-aors>
                     <info:entry>
                         <info:uri>
                             mailto:Ciccio@example.com
                         </info:uri>
                         <info:display-text>email</info:display-text>
                     </info:entry>
                 </info:associated-aors>
                 <info:endpoint entity="sip:Ciccio@example.com"/>
             </userInfo>
         </ccmp:userRequest>
     </ccmpRequest>
 </ccmp:ccmpRequest>


 2. "third party" userResponse message form the server:

 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
 <ccmp:ccmpResponse
        xmlns:info="urn:ietf:params:xml:ns:conference-info"
        xmlns:ccmp="urn:ietf:params:xml:ns:xcon:ccmp"
        xmlns:xcon="urn:ietf:params:xml:ns:xcon-conference-info">
     <ccmpResponse xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                   xsi:type="ccmp:ccmp-user-response-message-type">
             <confUserID>xcon-userid:Alice@example.com</confUserID>



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         <confObjID>xcon:8977794@example.com</confObjID>
         <operation>create</operation>
         <ccmp:response-code>success</ccmp:response-code>
         <ccmp:version>5</ccmp:version>
         <ccmp:userResponse>
                 <userInfo entity="xcon-userid:Ciccio@example.com">
                 <info:associated-aors>
                     <info:entry>
                         <info:uri>
                             mailto:Ciccio@example.com
                         </info:uri>
                         <info:display-text>email</info:display-text>
                     </info:entry>
                 </info:associated-aors>
                 <info:endpoint entity="sip:Ciccio@example.com"/>
             </userInfo>
         </ccmp:userResponse>
     </ccmpResponse>
 </ccmp:ccmpResponse>



    Figure 23: Alice adds a new user to the conference through the CCMP




























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8.  Locating a Conference Control Server

   If a conference control client is not pre-configured to use a
   specific conference control server for the requests, the client MUST
   first discover the conference control server before it can send any
   requests.  The result of the discovery process, is the address of the
   server supporting conferencing.  In this document, the result is an
   http: or https: URI, which identifies a conference server.

   This document proposes the use of DNS to locate the conferencing
   server.  U-NAPTR resolution for conferencing takes a domain name as
   input and produces a URI that identifies the conferencing server.
   This process also requires an Application Service tag and an
   Application Protocol tag, which differentiate conferencing-related
   NAPTR records from other records for that domain.

   Section 13.4.1 defines an Application Service tag of "XCON", which is
   used to identify the centralized conferencing (XCON) server for a
   particular domain.  The Application Protocol tag "CCMP", defined in
   Section 13.4.2, is used to identify an XCON server that understands
   the CCMP protocol.

   The NAPTR records in the following example Figure 24 demonstrate the
   use of the Application Service and Protocol tags.  Iterative NAPTR
   resolution is used to delegate responsibility for the conferencing
   service from "zonea.example.com." and "zoneb.example.com." to
   "outsource.example.com.".



             zonea.example.com.
             ;;       order pref flags
             IN NAPTR 100   10   ""  "XCON:CCMP" (     ; service
             ""                                        ; regex
             outsource.example.com.                    ; replacement
             )
             zoneb.example.com.
             ;;       order pref flags
             IN NAPTR 100   10   ""  "XCON:CCMP" (     ; service
             ""                                        ; regex
             outsource.example.com.                    ; replacement
             )
             outsource.example.com.
             ;;       order pref flags
             IN NAPTR 100   10   "u"  "XCON:CCMP" (    ; service
             "!*.!https://confs.example.com/!"         ; regex
             .                                         ; replacement
             )



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             Figure 24: Sample XCON:CCMP Service NAPTR Records

   Details for the "XCON" Application Service tag and the "CCMP"
   Application Protocol tag are included in Section 13.4.















































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9.  Managing Notifications

   In cases where the conference control client uses SIP [RFC3261] as
   the signaling protocol to participate in the conference, SIP event
   notification can be used.  This would REQUIRE the conference control
   client to implement the Conference event package for XCON
   [I-D.ietf-xcon-event-package].  This is the default mechanism for
   conferencing clients as is SIP for signaling per the XCON Framework
   [RFC5239].

   In the case where the interface to the conference server is entirely
   web based, there is a common mechanism for web-based systems that
   could be used - a "call back".  With this mechanism, the conference
   client provides the conference server with an HTTP URL which is
   invoked when a change occurs.  This is a common implementation
   mechanism for e-commerce.  This works well in the scenarios whereby
   the conferencing client is a web server that provides the graphical
   HTML user interface and uses CCMP as the backend interface to the
   conference server.  And, this model can co-exist with the SIP event
   notification model.  PC-based clients behind NATs could provide a SIP
   event URI, whereas web servers would probably find the HTTP model
   much easier to program.  The details of this approach are out of
   scope for the CCMP per se, thus the expectation is that a future
   specification will document this solution.



























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10.  HTTP Transport

   This section describes the use of HTTP [RFC2616] and HTTP Over TLS
   [RFC2818] as transport mechanisms for the CCMP protocol, which a
   conforming conference Server and Conferencing client MUST support.

   Although CCMP uses HTTP as a transport, it uses a strict subset of
   HTTP features, and due to the restrictions of some features, a
   conferencing server may not be a fully compliant HTTP server.  It is
   intended that a conference server can easily be built using an HTTP
   server with extensibility mechanisms, and that a conferencing client
   can trivially use existing HTTP libraries.  This subset of
   requirements helps implementors avoid ambiguity with the many options
   the full HTTP protocol offers.

   A conferencing client that conforms to this specification is not
   required to support HTTP authentication [RFC2617] or cookies
   [RFC2965].  These mechanism are unnecessary because CCMP requests
   carry their own authentication information (in the "subject" field;
   see Section 6.1).

   A CCMP request is carried in the body of an HTTP POST request.  The
   conferencing client MUST include a Host header in the request.

   The MIME type of CCMP request and response bodies is "application/
   ccmp+xml".  The conference server and conferencing client MUST
   provide this value in the HTTP Content-Type and Accept header fields.
   If the conference server does not receive the appropriate Content-
   Type and Accept header fields, the conference server SHOULD fail the
   request, returning a 406 (not acceptable) response.  CCMP responses
   SHOULD include a Content-Length header.

   Conferencing clients MUST NOT use the "Expect" header or the "Range"
   header in CCMP requests.  The conference server MAY return 501 (not
   implemented) errors if either of these HTTP features are used.  In
   the case that the conference server receives a request from the
   conferencing client containing a If-* (conditional) header, the
   conference server SHOULD return a 412 (precondition failed) response.

   The POST method is the only method REQUIRED for CCMP.  If a
   conference server chooses to support GET or HEAD, it SHOULD consider
   the kind of application doing the GET.  Since a conferencing client
   only uses a POST method, the GET or HEAD MUST be either an escaped
   URL (e.g., somebody found a URL in protocol traces or log files and
   fed it into their browser) or somebody doing testing/ debugging.  The
   conference server could provide information in the CCMP response
   indicating that the URL corresponds to a conference server and only
   responds to CCMP POST requests or the conference server could instead



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   try to avoid any leak of information by returning a very generic HTTP
   error message such as 405 (method not allowed).

   The conference server populates the HTTP headers of responses so that
   they are consistent with the contents of the message.  In particular,
   the "CacheControl" header SHOULD be set to disable caching of any
   conference information by HTTP intermediaries.  Otherwise, there is
   the risk of stale information and/or the unauthorized disclosure of
   the information.  The HTTP status code MUST indicate a 2xx series
   response for all CCMP Response and Error messages.

   The conference server MAY redirect a CCMP request.  A conferencing
   client MUST handle redirects, by using the Location header provided
   by the server in a 3xx response.  When redirecting, the conferencing
   client MUST observe the delay indicated by the Retry-After header.
   The conferencing client MUST authenticate the server that returns the
   redirect response before following the redirect.  A conferencing
   client SHOULD authenticate the conference server indicated in a
   redirect.

   The conference server SHOULD support persistent connections and
   request pipelining.  If pipelining is not supported, the conference
   server MUST NOT allow persistent connections.  The conference server
   MUST support termination of a response by the closing of a
   connection.

   Implementations of CCMP that implement HTTP transport MUST implement
   transport over TLS [RFC2818].  TLS provides message integrity and
   confidentiality between the conference control client and the
   conference control server.  The conferencing client MUST implement
   the server authentication method described in HTTPS [RFC2818].  The
   device uses the URI obtained during conference server discovery to
   authenticate the server.  The details of this authentication method
   are provided in section 3.1 of HTTPS [RFC2818].  When TLS is used,
   the conferencing client SHOULD fail a request if server
   authentication fails.















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11.  Security Considerations

   As identified in the XCON framework [RFC5239], there are a wide
   variety of potential attacks related to conferencing, due to the
   natural involvement of multiple endpoints and the capability to
   manipulate the data on the conference server using CCMP.  Examples of
   attacks include the following: an endpoint attempting to listen to
   conferences in which it is not authorized to participate, an endpoint
   attempting to disconnect or mute other users, and theft of service by
   an endpoint in attempting to create conferences it is not allowed to
   create.

   The following summarizes the security considerations for CCMP:

   1.  The client MUST determine the proper conference server.  The
       conference server discovery is described in Section 8.

   2.  The client MUST connect to the proper conference server.  The
       mechanisms for addressing this security consideration are
       described in Section 11.1.

   3.  The protocol MUST support a confidentiality and integrity
       mechanism.  As described in Section 10, implementations of CCMP
       MUST implement the HTTP transport over TLS [RFC2818].

   4.  There are security issues associated with the authorization to
       perform actions on the conferencing system to invoke specific
       capabilities.  A conference server SHOULD ensure that only
       authorized entities can manipulate the conference data.  The
       mechanisms for addressing this security consideration are
       described in Section 11.2.

   5.  The privacy and security of the identity of a user in the
       conference MUST be assured.  The mechanisms to ensure the
       security and privacy of identity are discussed in Section 11.3.

   6.  A final issue is related to Denial of Service (DoS) attacks on
       the conferencing server itself.  In order to minimize the
       potential for DoS attacks, it is RECOMMENDED that conferencing
       systems require user authentication and authorization for any
       client participating in a conference.  This can be accomplished
       through the use of the mechanisms described in Section 11.2, as
       well as by using the security mechanisms associated with the
       specific signaling (e.g., SIPS) and media protocols (e.g., SRTP).







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11.1.  Assuring that the Proper Conferencing Server has been contacted

   When the CCMP transaction is conducted using TLS [RFC5246], the
   conference server can authenticate its identity, either as a domain
   name or as an IP address, to the conference client by presenting a
   certificate containing that identifier as a subjectAltName (i.e., as
   an iPAddress or dNSName, respectively).  With the use of HTTP as a
   transport for CCMP, this is exactly the authentication described by
   TLS [RFC2818].  If the client has external information as to the
   expected identity or credentials of the proper conference server
   (e.g., a certificate fingerprint), these checks MAY be omitted.  Any
   implementation of CCMP MUST be capable of being transacted over TLS
   so that the client can request the above authentication, and a
   conference server implementation MUST include this feature.  Note
   that in order for the presented certificate to be valid at the
   client, the client must be able to validate the certificate.  In
   particular, the validation path of the certificate must end in one of
   the client's trust anchors, even if that trust anchor is the
   conference server certificate itself.

11.2.  User Authentication and Authorization

   Many policy authorization decisions are based on the identity of the
   user or the role that a user may have.  The conferencing server MUST
   implement mechanisms for authentication of users to validate their
   identity.  There are several ways that a user might authenticate its
   identity to the system.  For users joining a conference using one of
   the call signaling protocols, the user authentication mechanisms for
   the specific protocol can be used.  For the case of users joining the
   conference using the CCMP, TLS is RECOMMENDED.

   The XCON Framework [RFC5239] provides an overview of other
   authorization mechanisms.  In the cases where a user is authorized
   via multiple mechanisms, it is RECOMMENDED that the conference server
   correlate the authorization of the CCMP interface with other
   authorization mechanisms - e.g., PSTN users that join with a PIN and
   control the conference using CCMP.  When a conference server presents
   the identity of authorized users, it MAY provide information about
   the way the identity was proven or verified by the system.  A
   conference server can also allow a completely unauthenticated user
   into the system - this information SHOULD also be communicated to
   interested parties.

   Once a user is authenticated and authorized through the various
   mechanisms available on the conference server, the conference server
   MUST allocate a conference user identifier (XCON-USERID) and SHOULD
   associate the XCON-USERID with any signaling specific user
   identifiers that were used for authentication and authorization.



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   This XCON-USERID can be provided to a specific user through the
   conference notification interface and MUST be provided to users that
   interact with the conferencing system using the CCMP (i.e., in the
   appropriate CCMP response messages).  This conference user identifier
   is REQUIRED for any subsequent operations on the conference object.

11.3.  Security and Privacy of Identity

   An overview of the required privacy and anonymity for users of a
   conferencing system are provided in the XCON Framework [RFC5239].
   The security of the identity in the form of the XCON-USERID is
   provided in the CCMP protocol through the use of TLS.

   The conference server SHOULD provide mechanisms to ensure the privacy
   of the XCON-USERID.  This is accomplished by the conference client
   manipulation of the "provide-anonymity" element defined in the XCON
   data model ([I-D.ietf-xcon-common-data-model].  The "provide-
   anonymity" element controls the degree to which a user reveals their
   identity.  The conference client MUST set the "provide-anonymity"
   element to "hidden" if the user does not want other participants to
   even be aware that there is an additional participant in the
   conference.  The conference client MUST set the "provide-anonymity"
   field to "private" if the user wants to be entirely "anonymous"
   (i.e., other participants are aware that there is another
   participant, but have no information as to their identity).  The
   conference client MUST set the "provide-anonymity" field to "semi-
   private" if their identity is only to be revealed to other
   participants or users that have a higher level authorization (e.g., a
   conferencing system can be configured such that an administrator can
   see all users).  To provide the required privacy, the conference
   client SHOULD include the "provide-anonymity" element in the
   "confInfo" parameter in a CCMP confRequest message with an "update"
   or "create" operation or in the "userInfo" parameter in a CCMP
   userRequest message with an "update" or "create" operation, to ensure
   the user is provided the appropriate level of privacy.  If the
   "provide-anonymity" element is not included in the conference object,
   then other users can see the participant's identity.














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12.  XML Schema

   This section provides the XML schema definition of the "application/
   ccmp+xml" format.


 <?xml version="1.0" encoding="utf-8"?>
   <xs:schema
      targetNamespace="urn:ietf:params:xml:ns:xcon:ccmp"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xmlns="urn:ietf:params:xml:ns:xcon:ccmp"
      xmlns:tns="urn:ietf:params:xml:ns:xcon:ccmp"
      xmlns:dm="urn:ietf:params:xml:ns:xcon-conference-info"
      xmlns:info="urn:ietf:params:xml:ns:conference-info"
      xmlns:xs="http://www.w3.org/2001/XMLSchema">


      <xs:import namespace="urn:ietf:params:xml:ns:xcon-conference-info"
                 schemaLocation="DataModel.xsd"/>
      <xs:import namespace="urn:ietf:params:xml:ns:conference-info"
                 schemaLocation="rfc4575.xsd"/>

      <xs:element name="ccmpRequest" type="ccmp-request-type" />
      <xs:element name="ccmpResponse" type="ccmp-response-type" />

   <!-- CCMP request definition -->

   <xs:complexType name="ccmp-request-type">
       <xs:sequence>
           <xs:element name="ccmpRequest"
                       type="ccmp-request-message-type" />
       </xs:sequence>
   </xs:complexType>

   <!-- CCMP response definition -->

   <xs:complexType name="ccmp-response-type">
       <xs:sequence>
           <xs:element name="ccmpResponse"
                       type="ccmp-response-message-type" />
       </xs:sequence>
   </xs:complexType>

   <!--  Definition of ccmp-request-message-type -->

   <xs:complexType abstract="true"
                   name="ccmp-request-message-type">
       <xs:sequence>



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           <xs:element name="subject" type="subject-type"
                       minOccurs="0" maxOccurs="1" />
           <xs:element name="confUserID" type="xs:string"
                       minOccurs="0" maxOccurs="1" />
           <xs:element name="confObjID" type="xs:string"
                       minOccurs="0" maxOccurs="1" />
           <xs:element name="operation" type="operationType"
                       minOccurs="0" maxOccurs="1" />
           <xs:element name="conference-password" type="xs:string"
                       minOccurs="0" maxOccurs="1" />
          <xs:any namespace="##other" processContents="lax"
                  minOccurs="0" maxOccurs="unbounded"/>
      </xs:sequence>
      <xs:anyAttribute namespace="##any" processContents="lax"/>
 </xs:complexType>

   <!-- blueprintsRequest -->

   <xs:complexType name="ccmp-blueprints-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="blueprintsRequest" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- blueprintsRequestType -->

   <xs:element name="blueprintsRequest" type="blueprintsRequestType"/>

   <xs:complexType name="blueprintsRequestType">
       <xs:sequence>
           <xs:element name="xpathFilter" type="xs:string"
                       minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!--  blueprintRequest -->

   <xs:complexType name="ccmp-blueprint-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>



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                   <xs:element ref="blueprintRequest" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- blueprintRequestType -->

   <xs:element name="blueprintRequest" type="blueprintRequestType" />

   <xs:complexType name="blueprintRequestType">
       <xs:sequence>
           <xs:element name="blueprintInfo"
                       type="info:conference-type" minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!-- confsRequest -->

   <xs:complexType name="ccmp-confs-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="confsRequest" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- confsRequestType -->

   <xs:element name="confsRequest" type="confsRequestType" />

   <xs:complexType name="confsRequestType">
       <xs:sequence>
           <xs:element name="xpathFilter" type="xs:string"
                       minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                  minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!-- confRequest -->




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   <xs:complexType name="ccmp-conf-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="confRequest" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
    </xs:complexType>

   <!-- confRequestType -->

   <xs:element name="confRequest" type="confRequestType" />

   <xs:complexType name="confRequestType">
       <xs:sequence>
           <xs:element name="confInfo" type="info:conference-type"
                       minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                  minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
 </xs:complexType>

   <!-- usersRequest -->

   <xs:complexType name="ccmp-users-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="usersRequest" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- usersRequestType -->

   <xs:element name="usersRequest" type="usersRequestType" />

   <xs:complexType name="usersRequestType">
       <xs:sequence>
           <xs:element name="usersInfo" type="info:users-type"
                       minOccurs="0" />
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>



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    </xs:complexType>

   <!-- userRequest -->

   <xs:complexType name="ccmp-user-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="userRequest" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- userRequestType -->

   <xs:element name="userRequest" type="userRequestType" />

   <xs:complexType name="userRequestType">
       <xs:sequence>
           <xs:element name="userInfo" type="info:user-type"
                       minOccurs="0" />
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!-- sidebarsByValRequest -->

   <xs:complexType name="ccmp-sidebarsByVal-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="sidebarsByValRequest" />
                </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

    <!-- sidebarsByValRequestType -->

    <xs:element name="sidebarsByValRequest"
                type="sidebarsByValRequestType" />

    <xs:complexType name="sidebarsByValRequestType">
        <xs:sequence>
            <xs:element name="xpathFilter"



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                        type="xs:string" minOccurs="0"/>
            <xs:any namespace="##other" processContents="lax"
                    minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
            <xs:anyAttribute namespace="##any" processContents="lax"/>
    </xs:complexType>

    <!-- sidebarsByRefRequest -->

    <xs:complexType name="ccmp-sidebarsByRef-request-message-type">
        <xs:complexContent>
            <xs:extension base="tns:ccmp-request-message-type">
                <xs:sequence>
                    <xs:element ref="sidebarsByRefRequest" />
                </xs:sequence>
            </xs:extension>
        </xs:complexContent>
    </xs:complexType>

   <!-- sidebarsByRefRequestType -->

   <xs:element name="sidebarsByRefRequest"
               type="sidebarsByRefRequestType" />

   <xs:complexType name="sidebarsByRefRequestType">
       <xs:sequence>
           <xs:element name="xpathFilter" type="xs:string"
                       minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!-- sidebarByValRequest -->

   <xs:complexType name="ccmp-sidebarByVal-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="sidebarByValRequest" />
               </xs:sequence>
            </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- sidebarByValRequestType -->




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   <xs:element name="sidebarByValRequest"
               type="sidebarByValRequestType"/>

   <xs:complexType name="sidebarByValRequestType">
       <xs:sequence>
           <xs:element name="sidebarByValInfo"
                       type="info:conference-type" minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
   <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!-- sidebarByRefRequest -->

   <xs:complexType name="ccmp-sidebarByRef-request-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-request-message-type">
               <xs:sequence>
                   <xs:element ref="sidebarByRefRequest" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- sidebarByRefRequestType -->

   <xs:element name="sidebarByRefRequest"
               type="sidebarByRefRequestType" />

   <xs:complexType name="sidebarByRefRequestType">
       <xs:sequence>
           <xs:element name="sidebarByRefInfo"
                       type="info:conference-type" minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!--  Definition of ccmp-response-message-type -->

   <xs:complexType abstract="true" name="ccmp-response-message-type">
       <xs:sequence>
           <xs:element name="confUserID" type="xs:string"
                       minOccurs="1" maxOccurs="1" />
           <xs:element name="confObjID" type="xs:string"
                       minOccurs="0" maxOccurs="1" />



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           <xs:element name="operation" minOccurs="0"
                       maxOccurs="1" />
           <xs:element ref="response-code" minOccurs="1"
                       maxOccurs="1" />
           <xs:element name="response-string" type="xs:string"
                       minOccurs="0" maxOccurs="1" />
           <xs:element name="version" type="xs:positiveInteger"
                       minOccurs="0" maxOccurs="1" />
           <xs:any namespace="##other" processContents="lax"
                       minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!-- blueprintsResponse -->

   <xs:complexType name="ccmp-blueprints-response-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-response-message-type">
               <xs:sequence>
                   <xs:element ref="blueprintsResponse" />
               </xs:sequence>
           </xs:extension>
       </xs:complexContent>
   </xs:complexType>

   <!-- blueprintsResponseType -->

   <xs:element name="blueprintsResponse" type="blueprintsResponseType"/>

   <xs:complexType name="blueprintsResponseType">
       <xs:sequence>
           <xs:element name="blueprintsInfo" type="info:uris-type"
                       minOccurs="0"/>
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

   <!-- blueprintResponse -->

   <xs:complexType name="ccmp-blueprint-response-message-type">
       <xs:complexContent>
           <xs:extension base="tns:ccmp-response-message-type">
               <xs:sequence>
                   <xs:element ref="blueprintResponse" />
               </xs:sequence>



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           </xs:extension>
       </xs:complexContent>
    </xs:complexType>

    <!-- blueprintResponseType -->

    <xs:element name="blueprintResponse" type="blueprintResponseType"/>

    <xs:complexType name="blueprintResponseType">
        <xs:sequence>
            <xs:element name="blueprintInfo" type="info:conference-type"
                        minOccurs="0"/>
            <xs:any namespace="##other" processContents="lax"
                    minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:anyAttribute namespace="##any" processContents="lax"/>
    </xs:complexType>

    <!-- confsResponse -->

    <xs:complexType name="ccmp-confs-response-message-type">
        <xs:complexContent>
            <xs:extension base="tns:ccmp-response-message-type">
                <xs:sequence>
                    <xs:element ref="confsResponse" />
                </xs:sequence>
            </xs:extension>
        </xs:complexContent>
    </xs:complexType>

    <!-- confsResponseType -->

    <xs:element name="confsResponse" type="confsResponseType" />

    <xs:complexType name="confsResponseType">
        <xs:sequence>
            <xs:element name="confsInfo" type="info:uris-type"
                        minOccurs="0"/>
            <xs:any namespace="##other" processContents="lax"
                    minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:anyAttribute namespace="##any" processContents="lax"/>
    </xs:complexType>

    <!-- confResponse -->

    <xs:complexType name="ccmp-conf-response-message-type">
        <xs:complexContent>



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            <xs:extension base="tns:ccmp-response-message-type">
                <xs:sequence>
                    <xs:element ref="confResponse"/>
                </xs:sequence>
            </xs:extension>
        </xs:complexContent>
    </xs:complexType>

    <!-- confResponseType -->

    <xs:element name="confResponse" type="confResponseType" />

    <xs:complexType name="confResponseType">
        <xs:sequence>
            <xs:element name="confInfo" type="info:conference-type"
                        minOccurs="0"/>
            <xs:any namespace="##other" processContents="lax"
                    minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:anyAttribute namespace="##any" processContents="lax"/>
    </xs:complexType>

    <!-- usersResponse -->

    <xs:complexType name="ccmp-users-response-message-type">
        <xs:complexContent>
            <xs:extension base="tns:ccmp-response-message-type">
                <xs:sequence>
                    <xs:element ref="usersResponse" />
                </xs:sequence>
            </xs:extension>
         </xs:complexContent>
    </xs:complexType>

    <!-- usersResponseType -->

    <xs:element name="usersResponse" type="usersResponseType" />

    <xs:complexType name="usersResponseType">
        <xs:sequence>
            <xs:element name="usersInfo" type="info:users-type"
                        minOccurs="0"/>
            <xs:any namespace="##other" processContents="lax"
                    minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:anyAttribute namespace="##any" processContents="lax"/>
    </xs:complexType>




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    <!-- userResponse -->

    <xs:complexType name="ccmp-user-response-message-type">
        <xs:complexContent>
            <xs:extension base="tns:ccmp-response-message-type">
                <xs:sequence>
                    <xs:element ref="userResponse" />
                </xs:sequence>
            </xs:extension>
        </xs:complexContent>
    </xs:complexType>

    <!-- userResponseType -->

    <xs:element name="userResponse" type="userResponseType" />

    <xs:complexType name="userResponseType">
        <xs:sequence>
            <xs:element name="userInfo" type="info:user-type"
                        minOccurs="0"/>
            <xs:any namespace="##other" processContents="lax"
                  minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:anyAttribute namespace="##any" processContents="lax"/>
    </xs:complexType>

    <!-- sidebarsByValResponse -->

    <xs:complexType name="ccmp-sidebarsByVal-response-message-type">
        <xs:complexContent>
            <xs:extension base="tns:ccmp-response-message-type">
                <xs:sequence>
                    <xs:element ref="sidebarsByValResponse" />
                </xs:sequence>
            </xs:extension>
        </xs:complexContent>
    </xs:complexType>

    <!-- sidebarsByValResponseType -->

    <xs:element name="sidebarsByValResponse"
                type="sidebarsByValResponseType" />

    <xs:complexType name="sidebarsByValResponseType">
        <xs:sequence>
            <xs:element name="sidebarsByValInfo"
                        type="info:sidebars-by-val-type" minOccurs="0"/>
            <xs:any namespace="##other" processContents="lax"



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                    minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:anyAttribute namespace="##any" processContents="lax"/>
    </xs:complexType>

    <!-- sidebarsByRefResponse -->

    <xs:complexType name="ccmp-sidebarsByRef-response-message-type">
        <xs:complexContent>
            <xs:extension base="tns:ccmp-response-message-type">
                <xs:sequence>
                    <xs:element ref="sidebarsByRefResponse" />
                </xs:sequence>
            </xs:extension>
       </xs:complexContent>
    </xs:complexType>

    <!-- sidebarsByRefResponseType -->

    <xs:element name="sidebarsByRefResponse"
                type="sidebarsByRefResponseType" />

    <xs:complexType name="sidebarsByRefResponseType">
        <xs:sequence>
            <xs:element name="sidebarsByRefInfo" type="info:uris-type"
                        minOccurs="0"/>
            <xs:any namespace="##other" processContents="lax"
                    minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:anyAttribute namespace="##any" processContents="lax"/>
    </xs:complexType>

    <!-- sidebarByValResponse -->

    <xs:complexType name="ccmp-sidebarByVal-response-message-type">
        <xs:complexContent>
            <xs:extension base="tns:ccmp-response-message-type">
                <xs:sequence>
                    <xs:element ref="sidebarByValResponse" />
                </xs:sequence>
            </xs:extension>
        </xs:complexContent>
    </xs:complexType>

    <!-- sidebarByValResponseType -->

    <xs:element name="sidebarByValResponse"
                type="sidebarByValResponseType" />



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    <xs:complexType name="sidebarByValResponseType">
        <xs:sequence>
            <xs:element name="sidebarByValInfo"
                        type="info:conference-type" minOccurs="0"/>
            <xs:any namespace="##other" processContents="lax"
                    minOccurs="0" maxOccurs="unbounded"/>
         </xs:sequence>
         <xs:anyAttribute namespace="##any" processContents="lax"/>
    </xs:complexType>

    <!-- sidebarByRefResponse -->

    <xs:complexType name="ccmp-sidebarByRef-response-message-type">
        <xs:complexContent>
            <xs:extension base="tns:ccmp-response-message-type">
                <xs:sequence>
                    <xs:element ref="sidebarByRefResponse" />
                 </xs:sequence>
            </xs:extension>
        </xs:complexContent>
    </xs:complexType>

    <!-- sidebarByRefResponseType -->

    <xs:element name="sidebarByRefResponse"
                type="sidebarByRefResponseType" />

    <xs:complexType name="sidebarByRefResponseType">
        <xs:sequence>
            <xs:element name="sidebarByRefInfo"
                        type="info:conference-type" minOccurs="0"/>
            <xs:any namespace="##other" processContents="lax"
                    minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:anyAttribute namespace="##any" processContents="lax"/>
    </xs:complexType>

    <!-- response-code -->

    <xs:element name="response-code" type="response-codeType" />

    <xs:simpleType name="response-codeType">
        <xs:restriction base="xs:token">
             <xs:enumeration value="success"/>
             <xs:enumeration value="updateFailed"/>
             <xs:enumeration value="authorizationRequired"/>
             <xs:enumeration value="badRequest"/>
             <xs:enumeration value="unauthorized"/>



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             <xs:enumeration value="forbidden"/>
             <xs:enumeration value="objectNotFound"/>
             <xs:enumeration value="userNotFound"/>
             <xs:enumeration value="invalidConfUserID"/>
             <xs:enumeration value="confPasswordRequired"/>
             <xs:enumeration value="invalidConfPassword"/>
             <xs:enumeration value="forbiddenDeleteParent"/>
             <xs:enumeration value="forbiddenChangeProtected"/>
             <xs:enumeration value="requestTimeout"/>
             <xs:enumeration value="serverInternalError"/>
             <xs:enumeration value="notImplemented"/>
             <xs:enumeration value="authenticationRequired"/>
           </xs:restriction>
         </xs:simpleType>

          <!-- operationType -->

         <xs:simpleType name="operationType">
           <xs:restriction base="xs:token">
             <xs:enumeration value="retrieve"/>
             <xs:enumeration value="create"/>
             <xs:enumeration value="update"/>
             <xs:enumeration value="delete"/>
           </xs:restriction>
         </xs:simpleType>

   <!-- subject-type -->

   <xs:complexType name="subject-type">
       <xs:sequence>
           <xs:element name="username" type="xs:string"
                       minOccurs="0" maxOccurs="1" />
           <xs:element name="password" type="xs:string"
                       minOccurs="0" maxOccurs="1" />
           <xs:any namespace="##other" processContents="lax"
                   minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##any" processContents="lax"/>
   </xs:complexType>

 </xs:schema>



                                 Figure 25






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13.  IANA Considerations

   This document registers a new XML namespace, a new XML schema, and
   the MIME type for the schema.  This document also registers the
   "XCON" Application Service tag and the "CCMP" Application Protocol
   tag.  This document also defines registries for the CCMP operation
   types and response codes.

13.1.  URN Sub-Namespace Registration

   This section registers a new XML namespace,
   ""urn:ietf:params:xml:ns:xcon:ccmp"".

      URI: "urn:ietf:params:xml:ns:xcon:ccmp"

      Registrant Contact: IETF, XCON working group, (xcon@ietf.org),
      Mary Barnes (mary.barnes@nortel.com).

      XML:


         BEGIN
           <?xml version="1.0"?>
           <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
             "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
           <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
             <head>
               <title>CCMP Messages</title>
             </head>
             <body>
               <h1>Namespace for CCMP Messages</h1>
               <h2>urn:ietf:params:xml:ns:xcon:ccmp</h2>
   [[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX
       with the RFC number for this specification.]]
               <p>See <a href="[[RFC URL]]">RFCXXXX</a>.</p>
             </body>
           </html>
         END


13.2.  XML Schema Registration

   This section registers an XML schema as per the guidelines in
   [RFC3688].







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   URI:  urn:ietf:params:xml:schema:xcon:ccmp

   Registrant Contact:  IETF, XCON working group, (xcon@ietf.org), Mary
      Barnes (mary.barnes@nortel.com).

   Schema:  The XML for this schema can be found as the entirety of
      Section 12 of this document.

13.3.  MIME Media Type Registration for 'application/ccmp+xml'

   This section registers the "application/ccmp+xml" MIME type.

   To:  ietf-types@iana.org

   Subject:  Registration of MIME media type application/ccmp+xml

   MIME media type name:  application

   MIME subtype name:  ccmp+xml

   Required parameters:  (none)

   Optional parameters:  charset
      Indicates the character encoding of enclosed XML for which the
      default is UTF-8.

   Encoding considerations:  Uses XML, which can employ 8-bit
      characters, depending on the character encoding used.  See RFC
      3023 [RFC3023], section 3.2.

   Security considerations:  This content type is designed to carry
      protocol data related conference control.  Some of the data could
      be considered private and thus should be protected.

   Interoperability considerations:  None.

   Published specification:  RFC XXXX [[NOTE TO IANA/RFC-EDITOR: Please
      replace XXXX with the RFC number for this specification.]]

   Applications which use this media type:  Centralized Conferencing
      control clients and servers.

   Additional Information:  Magic Number(s): (none)
      File extension(s): .xml
      Macintosh File Type Code(s): (none)






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   Person & email address to contact for further information:  Mary
      Barnes <mary.barnes@nortel.com>

   Intended usage:  LIMITED USE

   Author/Change controller:  The IETF

   Other information:  This media type is a specialization of
      application/xml [RFC3023], and many of the considerations
      described there also apply to application/ccmp+xml.

13.4.  DNS Registrations

   Section 13.4.1 defines an Application Service tag of "XCON", which is
   used to identify the centralized conferencing (XCON) server for a
   particular domain.  The Application Protocol tag "CCMP", defined in
   Section 13.4.2, is used to identify an XCON server that understands
   the CCMP protocol.

13.4.1.  Registration of a Conference Control Server Application Service
         Tag

   This section registers a new S-NAPTR/U-NAPTR Application Service tag
   for XCON, as mandated by [RFC3958].

   Application Service Tag: XCON

   Intended usage: Identifies a server that supports centralized
   conferencing.

   Defining publication: RFCXXXX

   Contact information: The authors of this document

   Author/Change controller: The IESG

13.4.2.  Registration of a Conference Control Server Application
         Protocol Tag for CCMP

   This section registers a new S-NAPTR/U-NAPTR Application Protocol tag
   for the CCMP protocol, as mandated by [RFC3958].

   Application Service Tag: CCMP

   Intended Usage: Identifies the Centralized Conferencing (XCON)
   Manipulation Protocol.

   Applicable Service Tag(s): XCON



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   Terminal NAPTR Record Type(s): U

   Defining Publication: RFCXXXX

   Contact Information: The authors of this document

   Author/Change Controller: The IESG

13.5.  CCMP Protocol Registry

   This document requests that the IANA create a new registry for the
   CCMP protocol including an initial registry for operation types and
   response codes.

13.5.1.  CCMP Message Types

   The CCMP messages are described in Section 5.1 and defined in the XML
   schema in Section 12.  The following summarizes the requested
   registry:

   Related Registry:   CCMP Message Types Registry

   Defining RFC:  RFC XXXX [NOTE TO IANA/RFC-EDITOR: Please replace XXXX
      with the RFC number for this specification.]

   Registration/Assignment Procedures:  New CCMP message types are
      allocated on a specification required basis.

   Registrant Contact:  IETF, XCON working group, (xcon@ietf.org), Mary
      Barnes (mary.barnes@nortel.com).

   This section pre-registers the following initial CCMP message types:

   blueprintsRequest:  Used by a conference control client to query a
      conferencing system for its capabilities, in terms of available
      conference blueprints.

   blueprintsResponse:  The blueprintsResponse returns a list of
      blueprints supported by the specific conference server.

   confsRequest:  Used by a conference control client to query a
      conferencing system for its scheduled/active conferences.

   confsResponse:  The "confsResponse" returns the list of the currently
      activated/scheduled conferences at the server.






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   confRequest:  The "confRequest" is used to create a conference object
      and/or to request an operation on the conference object as a
      whole.

   confResponse:  The "confResponse" indicates the result of the
      operation on the conference object as a whole.

   userRequest:  The "userRequest" is used to request an operation on
      the "user" element in the conference object.

   userResponse:  The "userResponse" indicates the result of the
      requested operation on the "user" element in the conference
      object.

   usersRequest  This "usersRequest" is used to manipulate the "users"
      element in the conference object, including parameters such as the
      "allowed-users-list", "join-handling", etc.

   usersResponse:  This "usersResponse" indicates the result of the
      request to manipulate the "users" element in the conference
      object.

   sidebarRequest:  This "sidebarRequest" is used to retrieve the
      information related to a sidebar or to create, change or delete a
      specific sidebar.

   sidebarResponse:  This "sidebarResponse" indicates the result of the
      sidebarRequest.

13.5.2.  CCMP Response Codes

   The following summarizes the requested registry for CCMP Response
   codes:

   Related Registry:   CCMP Response Code Registry

   Defining RFC:  RFC XXXX [NOTE TO IANA/RFC-EDITOR: Please replace XXXX
      with the RFC number for this specification.]

   Registration/Assignment Procedures:  New response codes are allocated
      on a first-come/first-serve basis with specification required.

   Registrant Contact:  IETF, XCON working group, (xcon@ietf.org), Mary
      Barnes (mary.barnes@nortel.com).

   This section pre-registers the following thirteen initial response
   codes as described above in Section 5.1:




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   success:  This code indicates that the request was successfully
      processed.

   updateFailed:  This code indicates that a requested "update" cannot
      be successfully completed by the server.  An example of such
      situation is when the modification of an object cannot be applied
      due to conflicts arising at the server's side (e.g. because the
      client version of the object is an obsolete one and the requested
      modifications collide with the up-to-date state of the object
      stored at the server).

   badRequest:  This code indicates that the request was badly formed in
      some fashion.

   unauthorized:  This code indicates that the user was not authorized
      for the specific operation on the conference object.

   forbidden:  This code indicates that the specific operation is not
      valid for the target conference object.

   objectNotFound:  This code indicates that the specific conference
      object was not found.

   userNotFound:  This code is returned in answer to a "userRequest/
      create" operation, in the case of a third-party invite, when the
      "confUserID" (contained in the "entity" attribute of the
      "userInfo" parameter) of the user to be added is unknown.

   invalidConfUserID:  This code is returned in the case of requests in
      which the "confUserID" of the sender is invalid.

   invalidConfPassword:  This code is returned in response to all
      requests wishing to access/manipulate a password-protected
      conference object, when the "conference-password" parameter
      contained in the request is wrong.

   confPasswordRequired:  This code is returned in response to all
      requests wishing to access/manipulate a password-protected
      conference object, when the "conference-password" parameter is
      missing in the request.

   authenticationRequired:  This code is returned in response whenever
      the server wants to authenticate the requestor through the
      "subject" parameter and such a parameter is not provided in the
      request.






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   forbiddenDeleteParent:  This code indicates that the conferencing
      system cannot delete the specific conference object because it is
      a parent for another conference object.

   forbiddenChangeProtected:  This code indicates that the target
      conference object cannot be changed (e.g., due to policies, roles,
      privileges, etc.).

   requestTimeout:  This code indicates that the request could not be
      processed within a reasonable time, with the time specific to a
      conferencing system implementation.

   serverInternalError:  This code indicates that the conferencing
      system experienced some sort of internal error.

   notImplemented:  This code indicates that the specific operation is
      not implemented on that conferencing system.


































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14.  Acknowledgments

   The authors appreciate the feedback provided by Dave Morgan, Pierre
   Tane, Lorenzo Miniero, Tobia Castaldi, Theo Zourzouvillys, Sean
   Duddy, Oscar Novo, Richard Barnes and Simo Veikkolainen.  Special
   thanks go to Roberta Presta for her invaluable contribution to this
   document.  Roberta has worked on the specification of the CCMP
   protocol at the University of Napoli for the preparation of her
   Master thesis.  She has also implemented the CCMP prototype used for
   the trials and from which the dumps provided in Section 7 have been
   extracted.








































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15.  Changes since last Version

   NOTE TO THE RFC-Editor: Please remove this section prior to
   publication as an RFC.

   The following summarizes the changes between the WG 03 and the 04:

   1.  Re-organized document based on feedback from Richard Barnes.

   2.  Editorial clarifications and nits, including those identified by
       Richard and Simo Veikkolainen.

   The following summarizes the changes between the WG 02 and the 03:

   1.  Clarified that the confUserID is optional in the generic CCMP
       request message for a userRequest with a "create" operation.

   2.  Added response-code (error cases) handling - a general section
       for each of the operations (as part of CCMP Response Code
       section), so we don't need to re-iterate for each of the messages
       and message specific cases as appropriate (e.g.,
       deleteParentFailed, modified)

   3.  Moved "operation" parameter to be part of general CCMP request
       and response messages since it is used for more than one message
       type.  And, it's necessary to define before describing the
       operation specific response-code handling.

   4.  Revised normative statements for the various protocol messages
       and operations - e.g., messages MUST include parameter x versus
       SHOULD, adding text for handling of cases where the SHOULDs don't
       happen and the SHOULD NOTs do.  Added descriptions for all the
       operation types, as appropriate.

   5.  Added lots more details in the security section.

   6.  Added section to describe requirements for an HTTP implementation
       to support CCMP.

   7.  Updated section on notifications - XCON SIP event package is
       default, with some discussion of an HTTP callback mechanism
       (ffs).

   8.  Misc editorial nits: qualifying message names in the text, etc.,
       etc., etc.

   The following summarizes the changes between the WG 01 and the 02:




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   1.  Changed the basic approach from REST to HTTP as a transport.
       This impacted most of the document - i.e., a major rewrite - 02
       is closer to 00 than the 01.

   2.  Added full example based on prototype.

   The following summarizes the changes between the WG 00 and the 01:

   1.  Changed the basic approach from using SOAP to REST - the
       fundamentals are the same in terms of schema, basic operations.
       This impacted most sections, in particular introduction and
       motivation.

   2.  Added new request types - blueprintsRequest, blueprintRequest and
       confsRequest.  The first replaces the optionsRequest and the
       latter allows the client to get a list of all active conferences.

   3.  Merged all requests into the basic operations table.  Added
       summary of RESTful examples (referenced by the basic operations
       table.

   4.  Added examples showing RESTful approach - i.e., HTTP methods for
       message exchange.

   5.  Removed requestID from the schema (it should be handle by the
       transport - e.g., HTTP).  Updated schema (based on current
       prototype - it still needs another revision.

   6.  Added placeholders for Notifications and Role Based Access
       Control.

   7.  Added some text for discovery using DNS (including IANA
       registrations)

   8.  Updated References: updated XCON FW RFC, SOAP/W3C moved to
       informational section.















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16.  References

16.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
              Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
              Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.

   [RFC2617]  Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
              Leach, P., Luotonen, A., and L. Stewart, "HTTP
              Authentication: Basic and Digest Access Authentication",
              RFC 2617, June 1999.

   [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.

   [RFC2965]  Kristol, D. and L. Montulli, "HTTP State Management
              Mechanism", RFC 2965, October 2000.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              January 2004.

   [RFC5239]  Barnes, M., Boulton, C., and O. Levin, "A Framework for
              Centralized Conferencing", RFC 5239, June 2008.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246, August 2008.

   [I-D.ietf-xcon-common-data-model]
              Novo, O., Camarillo, G., Morgan, D., and J. Urpalainen,
              "Conference Information Data Model for Centralized
              Conferencing (XCON)", draft-ietf-xcon-common-data-model-16
              (work in progress), February 2010.

16.2.  Informative References

   [REST]     Fielding, "Architectural Styles and the Design of Network-
              based Software Architectures", 2000.

   [RFC3023]  Murata, M., St. Laurent, S., and D. Kohn, "XML Media
              Types", RFC 3023, January 2001.

   [RFC3261]  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.



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   [RFC3958]  Daigle, L. and A. Newton, "Domain-Based Application
              Service Location Using SRV RRs and the Dynamic Delegation
              Discovery Service (DDDS)", RFC 3958, January 2005.

   [RFC3966]  Schulzrinne, H., "The tel URI for Telephone Numbers",
              RFC 3966, December 2004.

   [I-D.ietf-xcon-event-package]
              Camarillo, G., Srinivasan, S., Even, R., and J.
              Urpalainen, "Conference Event Package Data Format
              Extension for Centralized Conferencing (XCON)",
              draft-ietf-xcon-event-package-01 (work in progress),
              September 2008.

   [I-D.ietf-xcon-examples]
              Barnes, M., Boulton, C., Miniero, L., Presta, R., and S.
              Romano, "Centralized Conferencing Manipulation Protocol
              (CCMP) Call Flow Examples", draft-ietf-xcon-examples-02
              (work in progress), December 2009.

   [W3C.REC-soap12-part1-20030624]
              Gudgin, M., Mendelsohn, N., Hadley, M., Moreau, J., and H.
              Nielsen, "SOAP Version 1.2 Part 1: Messaging Framework",
              World Wide Web Consortium FirstEdition REC-soap12-part1-
              20030624, June 2003,
              <http://www.w3.org/TR/2003/REC-soap12-part1-20030624>.

   [W3C.REC-soap12-part2-20030624]
              Mendelsohn, N., Hadley, M., Gudgin, M., Moreau, J., and H.
              Nielsen, "SOAP Version 1.2 Part 2: Adjuncts", World Wide
              Web Consortium FirstEdition REC-soap12-part2-20030624,
              June 2003,
              <http://www.w3.org/TR/2003/REC-soap12-part2-20030624>.


















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Appendix A.  Appendix A: Other protocol models and transports considered
             for CCMP

   The operations on the objects can be implemented in at least two
   different ways, namely as remote procedure calls - using SOAP as
   described in Appendix A.1 and by defining resources following a
   RESTful architecture Appendix A.2.

   In both approaches, servers will have to recreate their internal
   state representation of the object with each update request, checking
   parameters and triggering function invocations.  In the SOAP
   approach, it would be possible to describe a separate operation for
   each atomic element, but that would greatly increase the complexity
   of the protocol.  A coarser-grained approach to the CCMP does require
   that the server process XML elements in updates that have not changed
   and that there can be multiple changes in one update.

   For CCMP, the resource (REST) model might appear more attractive,
   since the conference operations fit the CRUD approach.

   Neither of these approaches were considered ideal as SOAP was not
   considered to be general purpose enough for use in a broad range of
   operational environments.  It is quite awkward to apply a RESTful
   approach since the CCMP requires a more complex request/response
   protocol in order to maintain the data both in the server and at the
   client.  This doesn't map very elegantly to the basic request/
   response model, whereby a response typically indicates whether the
   request was successful or not, rather than providing additional data
   to maintain the synchronization between the client and server data.
   In addition, the CCMP clients may also receive the data in
   Notifications.  While the notification method or protocol used by
   some conferencing clients can be independent of the CCMP, the same
   data in the server is used for both the CCMP and Notifications - this
   requires a server application above the transport layer (e.g., HTTP)
   for maintaining the data, which in the CCMP model is transparent to
   the transport protocol.

A.1.  Using SOAP for the CCMP

   A remote procedure call (RPC) mechanism for the CCMP could use SOAP
   (Simple Object Access Protocol[W3C.REC-soap12-part1-20030624][W3C.REC
   -soap12-part2-20030624]), where conferences and the other objects are
   modeled as services with associated operations.  Conferences and
   other objects are selected by their own local identifiers, such as
   email-like names for users.  This approach has the advantage that it
   can easily define atomic operations that have well-defined error
   conditions.




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   All SOAP operations would use a single HTTP verb.  While the RESTful
   approach requires the use of a URI for each object, SOAP can use any
   token.

A.2.  A RESTful approach for the CCMP

   Conference objects can also be modeled as resources identified by
   URIs, with the basic CRUD operations mapped to the HTTP methods POST/
   PUT for creating objects, GET for reading objects, PATCH/POST/PUT for
   changing objects and DELETE for deleting them.  Many of the objects,
   such as conferences, already have natural URIs.

   CCMP can be mapped into the CRUD (Create, Read, Update, Delete)
   design pattern.  The basic CRUD operations are used to manipulate
   conference objects, which are XML documents containing the
   information characterizing a specified conference instance, be it an
   active conference or a conference blueprint used by the conference
   server to create new conference instances through a simple clone
   operation.

   Following the CRUD approach, CCMP could use a general-purpose
   protocol such as HTTP [RFC2616] to transfer domain-specific XML-
   encoded data objects defined in the Conference Information Data Model
   for Centralized Conferencing [I-D.ietf-xcon-common-data-model].

   Following on the CRUD approach, CCMP could follow the well-known REST
   (REpresentational State Transfer) architectural style [REST].  The
   CCMP could map onto the REST philosophy, by specifying resource URIs,
   resource formats, methods supported at each URI and status codes that
   have to be returned when a certain method is invoked on a specific
   URI.  A REST-style approach must ensure sure that all operations can
   be mapped to HTTP operations.

   The following summarizes the specific HTTP method that could be used
   for each of the CCMP Requests:

   Retrieve: HTTP GET could be used on XCON-URIs, so that clients can
   obtain data about conference objects in the form of XML data model
   documents.

   Create: HTTP PUT could be used to create a new object as identified
   by the XCON-URI or XCON-USERID.

   Change: Either HTTP PATCH or HTTP POST could be used to change the
   conference object identified by the XCON-URI.

   Delete: HTTP DELETE could be used to delete conference objects and
   parameters within conference objects identified by the XCON-URI.



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Internet-Draft                    CCMP                     February 2010


Authors' Addresses

   Mary Barnes
   Nortel

   Email: mary.barnes@nortel.com


   Chris Boulton
   NS-Technologies

   Email: chris@ns-technologies.com


   Simon Pietro Romano
   University of Napoli
   Via Claudio 21
   Napoli  80125
   Italy

   Email: spromano@unina.it


   Henning Schulzrinne
   Columbia University
   Department of Computer Science
   450 Computer Science Building
   New York, NY  10027

   Email: hgs+xcon@cs.columbia.edu





















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