XCON Working Group M. Barnes
Internet-Draft Nortel
Intended status: Standards Track C. Boulton
Expires: May 16, 2010 NS-Technologies
S P. Romano
University of Napoli
H. Schulzrinne
Columbia University
November 12, 2009
Centralized Conferencing Manipulation Protocol
draft-ietf-xcon-ccmp-04
Abstract
The Centralized Conferencing Manipulation Protocol (CCMP) can create,
retrieve, change and delete objects describing a centralized
conference, such as state and capabilities of the conference,
participants, and their roles. The conference information is
contained in XML documents and fragments conforming to the
centralized conferencing data model schema. Even though the goal of
the CCMP is to appropriately manage conference state, the mechanisms
upon which the protocol itself is built are based on a state-less
request/response paradigm. Conferencing clients send requests to
conference servers, which respond to the client with the conference
information.
Status of this Memo
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This Internet-Draft will expire on May 16, 2010.
Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the
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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 . . . . . . . . . . . . . . . . . . . . . 8
5. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 10
5.1. Protocol Operations . . . . . . . . . . . . . . . . . . . 10
5.2. Implementation Approach . . . . . . . . . . . . . . . . . 12
6. CCMP messages . . . . . . . . . . . . . . . . . . . . . . . . 13
6.1. CCMP Request Message Type . . . . . . . . . . . . . . . . 13
6.2. CCMP Response Message Type . . . . . . . . . . . . . . . . 14
6.3. Detailed messages . . . . . . . . . . . . . . . . . . . . 16
6.3.1. blueprintsRequest and blueprintsResponse . . . . . . . 19
6.3.2. confsRequest and confsResponse . . . . . . . . . . . . 21
6.3.3. blueprintRequest and blueprintResponse . . . . . . . . 22
6.3.4. confRequest and confResponse . . . . . . . . . . . . . 24
6.3.5. usersRequest and usersResponse . . . . . . . . . . . . 27
6.3.6. userRequest and userResponse . . . . . . . . . . . . . 30
6.3.7. sidebarsByValRequest and sidebarsByValResponse . . . . 34
6.3.8. sidebarByValRequest and sidebarByValResponse . . . . . 36
6.3.9. sidebarsByRefRequest and sidebarsByRefResponse . . . . 39
6.3.10. sidebarByRefRequest and sidebarByRefResponse . . . . . 41
6.4. CCMP Response Codes . . . . . . . . . . . . . . . . . . . 44
7. A complete example of the CCMP in action . . . . . . . . . . . 48
7.1. Alice retrieves the available blueprints . . . . . . . . . 48
7.2. Alice gets detailed information about a specific
blueprint . . . . . . . . . . . . . . . . . . . . . . . . 51
7.3. Alice creates a new conference through a cloning
operation . . . . . . . . . . . . . . . . . . . . . . . . 53
7.4. Alice updates conference information . . . . . . . . . . . 55
7.5. Alice inserts a list of users in the conference object . . 57
7.6. Alice joins the conference . . . . . . . . . . . . . . . . 59
7.7. Alice adds a new user to the conference . . . . . . . . . 61
8. Locating a Conference Control Server . . . . . . . . . . . . . 64
9. Managing Notifications . . . . . . . . . . . . . . . . . . . . 66
10. HTTP Transport . . . . . . . . . . . . . . . . . . . . . . . . 67
11. Security Considerations . . . . . . . . . . . . . . . . . . . 69
11.1. Assuring that the Proper Conferencing Server has been
contacted . . . . . . . . . . . . . . . . . . . . . . . . 70
11.2. User Authentication and Authorization . . . . . . . . . . 70
11.3. Security and Privacy of Identity . . . . . . . . . . . . . 71
12. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 72
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 83
13.1. URN Sub-Namespace Registration . . . . . . . . . . . . . . 83
13.2. XML Schema Registration . . . . . . . . . . . . . . . . . 83
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13.3. MIME Media Type Registration for 'application/ccmp+xml' . 84
13.4. DNS Registrations . . . . . . . . . . . . . . . . . . . . 85
13.4.1. Registration of a Conference Control Server
Application Service Tag . . . . . . . . . . . . . . . 85
13.4.2. Registration of a Conference Control Server
Application Protocol Tag for CCMP . . . . . . . . . . 85
13.5. CCMP Protocol Registry . . . . . . . . . . . . . . . . . . 86
13.5.1. CCMP Message Types . . . . . . . . . . . . . . . . . . 86
13.5.2. CCMP Response Codes . . . . . . . . . . . . . . . . . 87
14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 90
15. Changes since last Version . . . . . . . . . . . . . . . . . . 91
16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 93
16.1. Normative References . . . . . . . . . . . . . . . . . . . 93
16.2. Informative References . . . . . . . . . . . . . . . . . . 93
Appendix A. Appendix A: Other protocol models and transports
considered for CCMP . . . . . . . . . . . . . . . . . 95
A.1. Using SOAP for the CCMP . . . . . . . . . . . . . . . . . 95
A.2. A RESTful approach for the CCMP . . . . . . . . . . . . . 96
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 97
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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 conferencing client and conference control server
acting as client and server, respectively. The CCMP uses HTTP
[RFC2616] as the protocol to transfer the CCMP requests and
responses, which contain the domain-specific XML-encoded data objects
defined in the Conference Information Data Model for Centralized
Conferencing (XCON Data Model) [I-D.ietf-xcon-common-data-model].
Other protocol models such as the use of a REST (REpresentational
State Transfer) architectural style [REST] were considered.
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:
CRUD: CRUD stands for Create/Read/Update/Delete and indicates a
design pattern supporting creating, retrieving, updating and
destroying objects.
REST: REpresentational State Transfer (REST) is an architectural
style, i.e., a coordinated set of architectural constraints. REST
is based on the consideration that a software architecture can
often be specified as an appropriate configuration of components,
data and connectors, all coordinated through constraining their
mutual relationships. Coordination and constraints help achieve a
desired set of architectural properties. [REST]
SOAP: Simple Object Access Protocol defined in
[W3C.REC-soap12-part1-20030624] and
[W3C.REC-soap12-part2-20030624].
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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 | .
. +-------------------+ .
. ^ .
.........................|..............................
|
|Conference
|Control
|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 operations. Their identifiers are
widely used for creating the CCMP requests and responses. Such
identifiers, used in CCMP for the conference object (XCON-URI) and
conference user (XCON-USERID), are introduced in the XCON framework
and defined in the XCON data model [I-D.ietf-xcon-common-data-model].
The main conference objects and users features 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 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. An
object can mark certain of its properties as unalterable, so that
they cannot be overridden.
The schema for the conference object is defined in the XCON data
model. Conference objects are uniquely identified by the XCON-URI.
A client MAY specify a parent object (a conference or blueprint) from
which to inherit values.
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).
A variety of elements defined in the common <conference-info> element
as specified in the XCON data model are used to determine how a
specific user expects and is allowed to join a conference as a
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participant or as a user with specific privileges (e.g., observer).
For example, each <target> element representing a user in the
conference <allowed-user-list> shows a "method" attribute which
defines 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. "dial-in" is the
default. If the conference is currently active, dial-out users are
contacted immediately; otherwise, they are contacted at the start of
the conference. The conference control protocol provides a mean to
manipulate these and other kinds of user-related features.
The conference control server assigns a unique Conference User
Identifier (XCON-USERID) to each conferencing system user. The
conference control server uses the XCON-USERID to change or delete
<user> elements. Depending upon policies and privileges, specific
conference control clients MAY also manipulate <user> elements.
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5. Protocol Overview
CCMP is a client-server, XML-based, state-less protocol, which has
been specifically conceived to provide users with the necessary means
for the creation, retrieval, modification and deletion of conference
objects.
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.
Conference-related information is encapsulated into CCMP messages in
the form of documents or document fragments compliant with the XCON
data model representation. 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 active conferences and/or
blueprints available at the server.
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:
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. <sidebars-by-value> elements) and external
to it (i.e. <sidebars-by-ref> elements),
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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
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 except those associated
with the retrieval of either the list of blueprints or the list of
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conferences will have to contain a mandatory "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.
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 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:
confUserId: An optional parameter containing the XCON-USERID of the
client. The "confUserID" parameter is used to determine if the
conference control client has the authority to perform the
operation, as well as other Authorization, Authentication and
Accounting (AAA) procedures. The attribute 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.
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]).
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.
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<xs:element name="ccmpRequest" type="ccmp-request-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>
<!-- Definition of ccmp-request-message-type -->
<xs:complexType abstract="true"
name="ccmp-request-message-type">
<xs:sequence>
<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="password" type="xs:string"
minOccurs="0" maxOccurs="1" />
</xs:sequence>
</xs:complexType>
Figure 2: Structure of CCMP Request messages
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.
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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.
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 responseCode of
"badRequest". The details for the specialized messages and
associated parameters are provided in Section 6.3.
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<xs:element name="ccmpResponse" type="ccmp-response-type" />
<!-- 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-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" type="operationType"
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:sequence>
</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
2. confsRequest/confsResponse
3. blueprintRequest/blueprintResponse
4. confRequest/confResponse
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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 | | | | |
+---------------+------------+------------+------------+------------+
| blueprintsReq | Get list | N/A | N/A | N/A |
| uest | of | | | |
| | blueprints | | | |
| | | | | |
| ------------- | ---------- | ---------- | ---------- | ---------- |
| | | | | |
| blueprintRequ | Get | N/A* | N/A* | N/A* |
| est | blueprint | | | |
| | | | | |
| ------------- | ---------- | ---------- | ---------- | ---------- |
| | | | | |
| confsRequest | Get list | N/A | N/A | N/A |
| | of confs | | | |
| | (active, | | | |
| | etc.) | | | |
| | | | | |
| ------------- | ---------- | ---------- | ---------- | ---------- |
| | | | | |
| confRequest | Gets | Creates | Changes | Deletes |
| | conference | conference | conference | conference |
| | object or | object | object | Object as |
| | blueprint | | | a whole |
| | | | | |
| ------------- | ---------- | ---------- | ---------- | ---------- |
| | | | | |
| usersRequest | Gets | N/A | Changes | N/A |
| | specific | | specified | |
| | users | | users | |
| | element | | element | |
| | | | | |
| ------------- | ---------- | ---------- | ---------- | ---------- |
| | | | | |
| userRequest | Gets | Adds a | Changes | Deletes |
| | specific | user to a | specified | user |
| | user | conf (**) | user | element as |
| | element | | element | a whole |
| | | | | |
| ------------- | ---------- | ---------- | ---------- | ---------- |
| | | | | |
| sidebarsByVal | Gets | N/A | N/A | N/A |
| Request | sidebars-b | | | |
| | y -val | | | |
| | element | | | |
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| ------------- | ---------- | ---------- | ---------- | ---------- |
| | | | | |
| sidebarsByRef | Gets | N/A | N/A | N/A |
| Request | sidebars-b | | | |
| | y -ref | | | |
| | element | | | |
| | | | | |
| ------------- | ---------- | ---------- | ---------- | ---------- |
| | | | | |
| sidebarByValR | Gets a | Creates a | Adds or | Removes/ |
| equest | sidebar | sidebar by | modifies a | deletes |
| | element | cloning | sidebar | entire |
| | | existing | | sidebar |
| | | conf | | |
| | | object | | |
| | | | | |
| ------------- | ---------- | ---------- | ---------- | ---------- |
| | | | | |
| sidebarByRefR | Gets a | Creates | Adds or | Removes/ |
| equest | sidebar | sidebar by | modifies | deletes |
| | element | cloning | sidebar | entire |
| | | existing | | sidebar |
| | | conf | | |
| | | object | | |
+---------------+------------+------------+------------+------------+
Table 1: Request Type Operation Specific Processing
(**): This operation can involve the creation of an XCON-UserID, if
the sender does not add it in the "confUserId" parameter, 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. A
"blueprintsRequest" message REQUIRES no additional parameters beyond
those specified for the basic CCMP request message. The "confObjId"
and "operation" parameters MUST NOT be included in the request or
response for this transaction.
The associated "blueprintsResponse" message SHOULD contain, as shown
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in Figure 4, a "blueprintsInfo" parameter containing the above
mentioned XCON-URI list. If the "blueprintsInfo" parameter is empty,
the conference control client MAY attempt to use a local default
blueprint to create conferences. However, the handling in this
situation is specific to the conference control client
implementation.
<!-- blueprintsRequest -->
<xs:complexType name="ccmp-blueprints-request-message-type">
<xs:complexContent>
<xs:extension base="tns:ccmp-request-message-type"/>
</xs:complexContent>
</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:sequence>
</xs:complexType>
Figure 4: Structure of the blueprintsRequest and blueprintsResponse
messages
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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 A
"confsRequest" message REQUIRES no additional parameters beyond those
specified for the basic CCMP request message. 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. 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:complexContent>
</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:sequence>
</xs:complexType>
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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. The request MUST
include an "operation" parameter and a "confObjId" parameter. 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).
In the case of responseCode 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.
If a response code fo "objectNotFound" is received in a
"blueprintResponse" message, a conference control client may attempt
to retrieve another conference blueprint if more than one had been
received in the "blueprintsResponse" message. If there was only one
blueprint in the "blueprintsResponse" initially, then the client
should send another "blueprintsRequest" message to determine if there
may be new or additional blueprints for the specific conferencing
system. If this "blueprintsResponse" message contains no blueprints,
the handling is specific to the conference control client.
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<!-- 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>
<xs:element name="blueprintInfo"
type="info:conference-type" minOccurs="0"/>
</xs:sequence>
</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"/>
</xs:sequence>
</xs:complexType>
Figure 6: Structure of the blueprintRequest and blueprintResponse
messages
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6.3.4. confRequest and confResponse
With a "confRequest" message, CCMP clients can manipulate conference
objects associated with either active or registered conferences
(blueprints or reservations). The request MUST include an
"operation" parameter. Depending upon the type of "operation" a
"confObjId" parameter MAY be included. The "confObjId" parameter
contains the XCON-URI of the specific active or registered
conference. The requirements for inclusion of "confInfo" parameter
depends upon the specific "operation" in the confRequest/confResponse
and are detailed below. The detailed information included in the
"confInfo" parameter MUST follow the rules as specified in the XCON
Data Model document [I-D.ietf-xcon-common-data-model].
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 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, whereas the "confInfo" parameter describing the
conference to be created MUST be included in the confRequest.
In both cases, the confResponse, for a successful completion of a
"create" operation, contains a responseCode of "success" and MUST
contain the XCON-URI of the created conference in the "confObjID"
parameter. In addition, the "confInfo" parameter transporting the
created conference document MAY be included. Obviously, the newly
created object can be manipulated by the client through a subsequent
"update" operation. For example, after the creation and addition of
the participants, the creator may want to lock the conference object.
This can be accomplished with a confRequest with an operation of
"update" by setting the "locked" element in the confInfo included in
the confRequest message described below.
In the case of a confRequest with a "retrieve" operation, the
"confObjId" representing the XCON-URI of the target conference the
conference control client MUST be included and the "confInfo"
parameter SHOULD NOT be included in the request. The conferencing
server MUST ignore any "confInfo" parameter that is received in a
"confRequest" and this "confInfo" parameter MUST NOT be included in
the confResponse. If the confResponse for the "retrieve" operation
contains a responseCode of "success", the "confInfo" parameter MUST
be included in the response. The "confInfo" parameter MUST contain
the entire conference document describing the target conference
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object in its current state.
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". In the case of a confResponse with a responseCode of
"success", no additional information is required in the
"confResponse" message. A responseCode of "success" indicates that
the referenced conference document has been changed by the conference
server. A responseCode of "changeFailedProtected" indicates that the
conferencing client is not allowed to make the changes reflected in
the "confInfo" in the initial request. This could be due to
policies, roles, specific privileges, etc.), with the reason specific
to a conferencing system and its configuration. Thus, it is
RECOMMENDED that the client continue using the previous version of
the "confInfo", if the conference was active. If the conference was
not active, it is RECOMMENDED that the client revert to an original
version of the blueprint or use another blueprint - one previously
retrieved with a blueprintRequest or one obtained via a new
blueprintsRequest/blueprintRequest sequence.
In the case of a confRequest with a "delete" operation, the
"confObjId" representing the XCON-URI of the target conference MUST
be included and the "confInfo" SHOULD NOT be included in the request.
The conferencing server MUST ignore any "confInfo" parameter that is
received. The confResponse MUST contain the same "confObjId" that
was included in the confRequest. The confResponse MUST contain a
responseCode of "success" if the targeted conference is successfully
deleted. If the confResponse for the "retrieve" operation contains a
responseCode of "success", the confResponse SHOULD NOT contain the
"confInfo" parameter. 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 responseCode of
"deleteParentFailed".
The schema for the confRequest/confResponse pair is shown in
Figure 7.
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<!-- 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>
<!-- confRequestType -->
<xs:element name="confRequest" type="confRequestType" />
<xs:complexType name="confRequestType">
<xs:sequence>
<xs:element name="confInfo"
type="info:conference-type" minOccurs="0"/>
</xs:sequence>
</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"/>
</xs:sequence>
</xs:complexType>
Figure 7: Structure of the confRequest and confResponse messages
The following provides an example of the "confInfo" parameter
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required to change the title of a conference:
<conf-info entity="123">
<conference-description>
<display-text>New conference title</display-text>
</conference-description>
</conf-info>
Figure 8: Updating a conference object: modifying the title of a
conference
Similarly, to remove the title of an existing conference, an "update"
operation carrying the following "confInfo" parameter would do the
job.
<conf-info entity="123">
<conference-description>
<display-text/>
</conference-description>
</conf-info>
Figure 9: Updating a conference object: removing the title of a
conference
6.3.5. usersRequest and usersResponse
Through a usersRequest message the CCMP client manipulates the
<users> element of the conference document associated with the
conference identified by the "confObjId" parameter. Inside the
<users> element, along with the list of conference users, there is
information that the client may be interested in controlling, such as
the lists of 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.
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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 be 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 responseCode is "success", then the "usersInfo" parameter
SHOULD NOT be returned. Any "usersInfo" parameter that is
returned SHOULD be ignored. A responseCode of
"changeFailedProtected" indicates that the conferencing client is
not allowed to make the changes reflected in the "usersInfo" in
usersRequest message. This could be due to policies, roles,
specific privileges, etc.), with the reason specific to a
conferencing system and its configuration. Thus, it is
RECOMMENDED that the client continue using the previous version
of the "usersInfo".
Operations of "create" and "delete" are not applicable to a
usersRequest message and MUST NOT be considered by the server, which
means that a responseCode of "forbidden" MUST be included in the
usersResponse message.
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<!-- 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:sequence>
</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"/>
</xs:sequence>
</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
"responseCode" 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 responseCode 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
responseCode 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 an appropriate XCON-USERID. 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=null>
<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 "entity" attribute MUST NOT be included in the
request. The XCON-USERID generated by the conference server for
such a user MUST also be returned to the client as the value of
the "entity" attribute in the "userInfo" parameter of the response
if the responseCode is "success". This scenario is mainly
intended to support the case whereby an XCON aware client is added
to a conference by a third party, e.g. the chairperson of the
conference.
o Conferencing client obtains a new user profile in the context of a
conference: this case is handled in the same manner as the
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previous case associated with the creation of a user on behalf of
a third party when the XCON-USERID is unknown, thus indicating to
the conference server that the client wants a new XCON-USERID and
associated "userInfo" parameter to be allocated and populated
respectively.
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" MUST be included in the userRequest
message. This "confUserId" indicates the specific <user> element in
XCON data model, as reflected by the "entity" attribute in the <user>
element that the conference client is requesting to retrieve. The
"userInfo" parameter MUST NOT be included in the request. The
conferencing server MUST ignore any "userInfo" parameter that is
received in a "userRequest" and this "userInfo" parameter MUST NOT be
included in the userResponse. If the userResponse for the "retrieve"
operation contains a responseCode 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. In the
case of a user Response with a responseCode of "success", no
additional information is required in the "confResponse" message. A
responseCode of "success" indicates that the referenced user element
has been updated by the conference server. A responseCode of
"changeFailedProtected" 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
and its configuration. Thus, it is RECOMMENDED that the client
continue using the previous version of the "userInfo".
In the case of a userRequest with a "delete" operation, the
"confObjId" representing the XCON-URI of the target conference and
the "confUserID" associated with the specific <user> element (i.e.,
matching the "entity" attribute) that the conferencing client is
requesting to be deleted MUST be included in the userRequest message.
The userResponse MUST contain the same "confObjId" that was included
in the userRequest. The userResponse MUST contain a responseCode of
"success" if the target <user> element has been successfully deleted.
If the userResponse for the "delete" operation contains a
responseCode of "success", the userResponse MUST NOT contain the
"userInfo" parameter.
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<!-- 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:sequence>
</xs:complexType>
<!-- 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"/>
</xs:sequence>
</xs:complexType>
Figure 12: Structure of the userRequest and userResponse messages
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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. A
"sidebarsByValResponse" with a responseCode of "success" MUST contain
a "sidebarsByValInfo" parameter containing the desired <sidebars-by-
val> element. 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="sidebarsByValInfo"
type="info:sidebars-by-val-type" minOccurs="0"/>
</xs:sequence>
</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"/>
</xs:sequence>
</xs:complexType>
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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 is to be created. The "sidebarByValInfo" parameter
SHOULD NOT be included in the request, since, as envisaged in the
XCON framework ([RFC5239]), sidebars are always created by cloning
the main conference. Any "sidebarByValInfo" included in the request
MUST be ignored. The conference server sets the "active" element to
"false" of the cloned conference to reflect that it is a "reserved"
conference. The conference server MUST update the conference object
reflected by the "confObjID" parameter, in the sidebarbyVal request
message, from which the sidebar was created to reflect the newly
created sidebar. The newly created conference object MAY be included
in the response in the "sidebarByValInfo" parameter, if the
responseCode is "success". The URI of 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 "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.
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.
If an "operation" of "delete" is included in the sidebarByVal
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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.
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<!-- 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 -->
<xs:element name="sidebarByValRequest"
type="sidebarByValRequestType" />
<xs:complexType name="sidebarByValRequestType">
<xs:sequence>
<xs:element name="sidebarByValInfo"
type="info:conference-type" minOccurs="0"/>
</xs:sequence>
</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"/>
</xs:sequence>
</xs:complexType>
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Figure 14: Structure of the sidebarByValRequest and
sidebarByValResponse messages
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 responseCode 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.
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<!-- 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="sidebarsByRefInfo"
type="info:uris-type" minOccurs="0"/>
</xs:sequence>
</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"/>
</xs:sequence>
</xs:complexType>
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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 an "operation of "create", the "confObjId" parameter
representing the XCON-URI of the conference from which the sidebar is
to be created (cloned) MUST be included in all sidebarByRefRequest
messages. The "sidebarByRefInfo" parameter SHOULD NOT be included in
the request, since, as envisaged in the XCON framework ([RFC5239]),
sidebars are always created by cloning the main conference. Any
"sidebarByRefInfo" included in the request MUST be ignored. 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 for the newly
created sidebar. The newly created conference object MAY be included
in the response in the "sidebarByRefInfo" parameter with a
responseCode "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.
If an "operation" of "delete" is included in the sidebarByRef
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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
authorized to receive the notifications, of the deletion of the
sidebar.
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<!-- 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:sequence>
</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"/>
</xs:sequence>
</xs:complexType>
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Figure 16: Structure of the sidebarByRefRequest and
sidebarByRefResponse messages
6.4. CCMP Response Codes
All CCMP response messages MUST include a "responseCode". 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).
invalidPassword: Target conference object's password contained in
the request is wrong.
passwordRequired: Conference password missing in a request to access
a password-protected conference object.
unauthorized: User not allowed to perform the required operation.
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.
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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 "responseCode" of "objectNotFound", "userNotFound",
"deleteParentFailed" and "changeFailedProtected" are only applicable
to specific operations for specialized message responses and the
details are provided in Section 6.3. The following table summarizes
these "responseCodes" and the specialized message and operation to
which they are applicable:
+---------------+------------+------------+------------+------------+
| 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) | | | |
| | (*) | | | |
| | | | | |
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| ------------- | ---------- | ---------- | ---------- | ---------- |
| | | | | |
| 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 | |
+---------------+------------+------------+------------+------------+
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.
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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 responseCode SHOULD be treated by the
client in the same manner as a "serverInternalError" responseCode,
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
[spromano-09] This section has to be updated, since we added the
"operation" parameter in response messages. Hence, we first have to
update the schema file; then, we have to change the excrpts in this
section.
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 is
"Alice" 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 (whose "confUserId" is "Ciccio") 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
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blueprints, in the form of the standard XCON-URI of the blueprint,
plus additional (and optional) information, like its display-text and
purpose.
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) |
| - responseCode: 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 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-blueprints-response-message-type">
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<confUserID>xcon-userid:Alice@example.com</confUserID>
<ccmp:response-code>success</ccmp:response-code>
<ccmp:blueprintsResponse>
<blueprintsInfo>
<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:
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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
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 |
| - responseCode: 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 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-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>
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<xcon:floor-request-handling>confirm
</xcon:floor-request-handling>
<xcon:conference-floor-policy>
<xcon:floor id="audioLabel"></xcon:floor>
</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 |
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| - confUserID: Alice |
| - confObjId: newConfId |
| - operation: create |
| - responseCode: success |
| - 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:confResponse>
<confInfo entity="xcon:8977794@example.com">
<info:conference-description>
<info:display-text>
New conference by Alice cloned from AudioRoom
</info:display-text>
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<info:conf-uris>
<info:entry>
<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
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document to which the required changes have to be applied. As shown
in the picture, the response contains a code of "success", which
acknowledges the modifications requested by the client.
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 |
| - responseCode: success |
| - 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>
Alice's conference
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</info:display-text>
</info:conference-description>
</confInfo>
</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>update</operation>
<ccmp:response-code>success</ccmp:response-code>
<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 |
| - confObjId: 8977794 |
| - operation: update |
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| - usersInfo: usersUpdates |
|------------------------------------------------------>|
| |
| CCMP usersResponse message |
| - confUserID: Alice |
| - confObjId: 8977794 |
| - operation: update |
| - responseCode: success |
| - 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 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"
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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: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 |
| - confUserID: Alice |
| - confObjId: 8977794 |
| - operation: create |
| - responseCode: success |
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| - 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 from 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>
<confObjID>xcon:8977794@example.com</confObjID>
<operation>create</operation>
<ccmp:response-code>success</ccmp:response-code>
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<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 user to the
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
his current end-point. The picture below shows the transaction.
Notice how the "confUserId" parameter in the request is Alice's id,
whereas the <userInfo> element has no "entity" attribute and contains
information about a different user, thus indicating that the request
issued by the client is a third-party one. This is also reflected in
the response coming from the server, which this time contains a
"confUserID" parameter representing the conference user id of the
user just added to the conference with Alice's third-party request.
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 |
|------------------------------------------------------>|
| |
| CCMP userResponse message |
| - confUserID: ciccio |
| - confObjId: 8977794 |
| - operation: create |
| - responseCode: success |
| - userInfo: (null) |
|<------------------------------------------------------|
| |
. .
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. .
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>
<info:associated-aors>
<info:entry>
<info:uri>
mailto:ciccio@pernacchio.com
</info:uri>
<info:display-text>email</info:display-text>
</info:entry>
</info:associated-aors>
<info:endpoint entity="sip:ciccio@pernacchio.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:ciccio@example.com</confUserID>
<confObjID>xcon:8977794@example.com</confObjID>
<operation>create</operation>
<ccmp:response-code>success</ccmp:response-code>
<ccmp:userResponse/>
</ccmpResponse>
</ccmp:ccmpResponse>
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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 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 "confUserId" and
"password" fields; see Section 7.2.1).
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 -->
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<xs:complexType abstract="true"
name="ccmp-request-message-type">
<xs:sequence>
<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="password" type="xs:string"
minOccurs="0" maxOccurs="1" />
</xs:sequence>
</xs:complexType>
<!-- blueprintsRequest -->
<xs:complexType name="ccmp-blueprints-request-message-type">
<xs:complexContent>
<xs:extension base="tns:ccmp-request-message-type"/>
</xs:complexContent>
</xs:complexType>
<!-- 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>
<xs:element name="blueprintInfo"
type="info:conference-type"
minOccurs="0"/>
</xs:sequence>
</xs:complexType>
<!-- confsRequest -->
<xs:complexType name="ccmp-confs-request-message-type">
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<xs:complexContent>
<xs:extension base="tns:ccmp-request-message-type"/>
</xs:complexContent>
</xs:complexType>
<!-- 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>
<!-- confRequestType -->
<xs:element name="confRequest" type="confRequestType" />
<xs:complexType name="confRequestType">
<xs:sequence>
<xs:element name="confInfo"
type="info:conference-type"
minOccurs="0"/>
</xs:sequence>
</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" />
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</xs:sequence>
</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:sequence>
</xs:complexType>
<!-- sidebarsByValRequest -->
<xs:complexType name="ccmp-sidebarsByVal-request-message-type">
<xs:complexContent>
<xs:extension base="tns:ccmp-request-message-type"/>
</xs:complexContent>
</xs:complexType>
<!-- sidebarsByRefRequest -->
<xs:complexType name="ccmp-sidebarsByRef-request-message-type">
<xs:complexContent>
<xs:extension base="tns:ccmp-request-message-type"/>
</xs:complexContent>
</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" />
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</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<!-- sidebarByValRequestType -->
<xs:element name="sidebarByValRequest"
type="sidebarByValRequestType" />
<xs:complexType name="sidebarByValRequestType">
<xs:sequence>
<xs:element name="sidebarByValInfo"
type="info:conference-type"
minOccurs="0"/>
</xs:sequence>
</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:sequence>
</xs:complexType>
<!-- Definition of ccmp-response-message-type -->
<xs:complexType abstract="true"
name="ccmp-response-message-type">
<xs:sequence>
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<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:sequence>
</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:sequence>
</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"/>
</xs:sequence>
</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:sequence>
</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>
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</xs:complexType>
<!-- confResponseType -->
<xs:element name="confResponse" type="confResponseType" />
<xs:complexType name="confResponseType">
<xs:sequence>
<xs:element name="confInfo" type="info:conference-type"/>
</xs:sequence>
</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"/>
</xs:sequence>
</xs:complexType>
<!-- 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" />
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<xs:complexType name="userResponseType">
<xs:sequence>
<xs:element name="userInfo" type="info:user-type"/>
</xs:sequence>
</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"/>
</xs:sequence>
</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">
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<xs:sequence>
<xs:element name="sidebarsByRefInfo"
type="info:uris-type"/>
</xs:sequence>
</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"/>
</xs:sequence>
</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">
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<xs:sequence>
<xs:element name="sidebarByRefInfo"
type="info:conference-type"/>
</xs:sequence>
</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="badRequest"/>
<xs:enumeration value="unauthorized"/>
<xs:enumeration value="forbidden"/>
<xs:enumeration value="objectNotFound"/>
<xs:enumeration value="userNotFound"/>
<xs:enumeration value="invalidConfUserID"/>
<xs:enumeration value="passwordRequired"/>
<xs:enumeration value="invalidPassword"/>
<xs:enumeration value="forbiddenDeleteParent"/>
<xs:enumeration value="forbiddenChangeProtected"/>
<xs:enumeration value="requestTimeout"/>
<xs:enumeration value="serverInternalError"/>
<xs:enumeration value="notImplemented"/>
</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>
</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.
invalidPassword: This code is returned in response to all requests
wishing to access/manipulate a password-protected conference
object, when the "password" parameter contained in the request is
wrong.
passwordRequired: This code is returned in response to all requests
wishing to access/manipulate a password-protected conference
object, when the "password" parameter is missing in the request.
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.).
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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 responseCode (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 responseCode 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-14
(work in progress), November 2009.
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-01
(work in progress), July 2009.
[W3C.REC-soap12-part1-20030624]
Nielsen, H., Gudgin, M., Moreau, J., Mendelsohn, N., and
M. Hadley, "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]
Hadley, M., Mendelsohn, N., 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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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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