Internet Engineering Task Force (IETF) M. Barnes
Request for Comments: 6504 Polycom
Category: Informational L. Miniero
ISSN: 2070-1721 Meetecho
R. Presta
S P. Romano
University of Napoli
March 2012
Centralized Conferencing Manipulation Protocol (CCMP)
Call Flow Examples
Abstract
This document provides detailed call flows for the scenarios
documented in the Framework for Centralized Conferencing (XCON) (RFC
5239) and in the XCON scenarios (RFC 4597). The call flows document
the use of the interface between a conference control client and a
conference control server using the Centralized Conferencing
Manipulation Protocol (CCMP) (RFC 6503). The objective is to provide
detailed examples for reference by both protocol researchers and
developers.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6504.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
Barnes, et al. Informational [Page 1]
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction ....................................................3
2. Terminology .....................................................3
3. Overview ........................................................4
4. Working with CCMP ...............................................4
4.1. CCMP and the Data Model ....................................5
4.2. Using HTTP/TLS as a Transport ..............................6
4.3. Conference Notifications ..................................10
5. Conference Creation ............................................11
5.1. Basic Conference Creation .................................12
5.2. Conference Creation Using Blueprints ......................16
5.3. Conference Creation Using User-Provided Conference
Information ...............................................23
5.4. Cloning an Existing Conference ............................28
6. Conference Users Scenarios and Examples ........................31
6.1. Adding a Party ............................................32
6.2. Muting a Party ............................................35
6.3. Conference Announcements and Recordings ...................38
6.4. Monitoring for DTMF .......................................41
6.5. Entering a Password-Protected Conference ..................42
7. Sidebars Scenarios and Examples ................................44
7.1. Internal Sidebar ..........................................45
7.2. External Sidebar ..........................................54
7.3. Private Messages ..........................................60
7.4. Observing and Coaching ....................................64
8. Removing Participants and Deleting Conferences .................71
8.1. Removing a Party ..........................................71
8.2. Deleting a Conference .....................................74
9. Security Considerations ........................................75
10. Acknowledgements ..............................................76
11. References ....................................................76
11.1. Normative References .....................................76
11.2. Informative References ...................................76
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1. Introduction
This document provides detailed call flows for the scenarios
documented in the Framework for Centralized Conferencing (XCON)
[RFC5239] and in the XCON scenarios [RFC4597]. The XCON scenarios
describe a broad range of use cases taking advantage of the advanced
conferencing capabilities provided by a system realization of the
XCON framework. The call flows document the use of the interface
between a conference control client and a conference control server
using the Centralized Conferencing Manipulation Protocol (CCMP)
[RFC6503].
Due to the broad range of functionality provided by the XCON
framework and the flexibility of the CCMP messaging, these call flows
should not be considered inclusive of all the functionality that can
provided by the XCON framework and protocol implementations. These
flows represent a sample to provide an overview of the feature-rich
capabilities of the XCON framework and CCMP messaging for protocol
developers, software developers, and researchers.
2. Terminology
This document uses the same terminology as found in the Architectural
Framework for Media Server Control [RFC5567] and in the Media Control
Channel Framework Call Flow Examples [CALL-FLOWS], with the following
terms and abbreviations used in the call flows. Also, note that the
term "call flows" is used in a very generic sense in this document
since the media is not limited to voice. The calls supported by the
XCON framework and CCMP can consist of media such as text, voice, and
video, including multiple media types in a single active conference.
Conference and Media Control Client (CMCC): as defined in the XCON
framework. In the flows in this document, the CMCC is logically
equivalent to the use of a User Agent Client (UAC) as the client
notation in the media control call flows [CALL-FLOWS]. A CMCC
differs from a generic media client in being an XCON-aware entity,
thus, also being able to issue CCMP requests.
Conference Server (ConfS): In this document, the term "conference
server" is used interchangeably with the term "Application Server
(AS)" as used in the media control architectural framework
[RFC5567]. A conference server is intended to be able to act as a
conference control server, as defined in the XCON framework, i.e.,
it is able to handle CCMP requests and issue CCMP responses.
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Media Server (MS): as defined in the media control architectural
framework [RFC5567].
3. Overview
This document provides a sampling of detailed call flows that can be
implemented based on a system realization of the XCON framework
[RFC5239] and implementation of CCMP [RFC6503]. This is intended to
be a simple guide for the use of the conference control protocol
between the conference server and the conference control client. The
objective is to provide an informational base reference for protocol
developers, software developers, and researchers.
This document focuses on the interaction between the conference and
media control client and the conferencing system, specifically the
conference server. The scenarios are based on those described in the
XCON framework, many of which are based on the advanced conferencing
capabilities described in the XCON scenarios. Additional scenarios
have been added to provide examples of other real-life scenarios that
are anticipated to be supported by the framework. With the exception
of an initial example with media control messaging, the examples do
not include the details for the media control [RFC6505], call
signaling, or Binary Floor Control Protocols (BFCPs) [RFC4582]. This
document references the scenarios in the media control call flows
[CALL-FLOWS], SIP call control conferencing, [RFC4579], and BFCP
documents.
The rest of this document is organized as follows. Section 4
presents an overview on CCMP, together with some implementation-
related details and related matters like HTTPS transport and
notifications. Section 5 presents the reader with examples showing
the different approaches CCMP provides to create a new conference.
Section 6 more generally addresses the different user-related
manipulations that can be achieved by means of CCMP, by presenting a
number of interesting scenarios. Section 7 addresses several
scenarios that may involve the use of sidebars. Section 8 shows how
CCMP can be used to remove conferences and users from the system.
Finally, Section 9 provides a few details on the security
considerations when it comes to implementing CCMP.
4. Working with CCMP
This section provides a brief introduction as to how the Centralized
Conferencing Manipulation Protocol (CCMP) [RFC6503] works and how it
can be transported across a network. A typical CCMP interaction
focusing on relevant aspects of the client-server communication is
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described. Please note that this section assumes the reader has read
and understood the CCMP document. This section is intended to help
the reader understand the actual protocol interactions.
First, a description of the protocol itself is provided Section 4.1,
including some implementation considerations. In Section 4.2, an
effective CCMP interaction is presented by exploiting HTTPS as a
transport. Finally, notifications are described in Section 4.3.
The document then presents and describes some actual flows in detail
in the sections to follow.
4.1. CCMP and the Data Model
CCMP is an protocol based on XML [W3C.REC-xml-20081126]. It has been
designed as a request/response protocol. It is completely stateless,
which means implementations can safely handle transactions
independently from each other.
The protocol allows for the manipulation of conference objects and
related users. This manipulation allows a conference and media
control client (briefly CMCC in all the following sections) to
create, update, and remove basically everything that is related to
the objects handled by a conferencing system. This is reflected in
the allowed operations (retrieve, create, update, delete) and the
specified request types (ranging from the manipulation of blueprints
and conferences to users and sidebars). For instance, CCMP provides
ways to:
o retrieve the list of registered and/or active conferences in the
system;
o create new conferences by exploiting several different approaches;
o add/remove users to/from a conference;
o update a conference with respect to all of its aspects;
and so on.
While CCMP acts as the means to manipulate conference objects, CCMP
does not define these conference objects. A separate document
specifies how a conference object and all its components have to be
constructed (Conference Information Data Model for Centralized
Conferencing (XCON) [RFC6501]). CCMP, depending upon the request
type and the related operation, carries pieces of conference objects
(or any object as a whole) according to the aforementioned
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specification. This means that any implementation aiming at being
compliant with CCMP has to make sure that the transported objects are
completely compliant with the data model specification and coherent
with the constraints defined therein. To make this clearer, there
are elements that are mandatory in a conference object: issuing a
syntactically correct CCMP request that carries a wrong conference
object is doomed to result in a failure. For this reason, it is
suggested that the interested implementers take special care in
carefully checking the data model handlers as well in order to avoid
potential mistakes.
However, there are cases when a mandatory element in the data model
cannot be assigned in a conference object by a CCMP user. For
example, a CMCC may be requesting the direct creation of a new
conference; in this case, a conference object assumes an 'entity'
attribute uniquely identifying the conference to be in place. Thus,
the CMCC has no way to know a priori what the entity will be, since
it is generated by the ConfS after the request. For scenarios like
this one, the CCMP specification describes the use of a dedicated
placeholder wildcard (i.e., "AUTO_GENERATE_X", where X is an integer)
to make the conference object compliant with the data model: the
wildcard would then be replaced by the ConfS with the right value.
4.2. Using HTTP/TLS as a Transport
CCMP requires that implementations support HTTP/TLS as the transport
mechanism. Per CCMP, a CMCC sends a request as part of an HTTPS POST
message, and the ConfS would reply with a 200 OK HTTPS response. In
both cases, the HTTPS messages carry the CCMP messages as payload,
which is reflected in the Content-Type header
("application/ccmp+xml"). Figure 1 presents a ladder diagram of such
an interaction, which is followed by a dump of the exchanged HTTPS
messages for further analysis. The examples in the remainder of this
document show only the CCMP interactions.
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CMCC ConfS
| |
| 1. HTTPS POST (CCMP request) |
|--------------------------------------------->|
| |
| |--+ Parse request,
| | | update object
| |<-+ and reply
| |
| 2. 200 OK (CCMP response) |
|<---------------------------------------------|
| |
|--+ Parse response and |
| | update local copy |
|<-+ of conference object |
| |
' '
' '
Figure 1: CCMP on HTTPS
Per the protocol dump in the following lines, the CMCC has issued a
CCMP request (a blueprintRequest message asking for a blueprint
retrieval, i.e., with the element set to "retrieve" )
towards the ConfS. The request has been carried as payload of an
HTTPS POST (message 1.) towards a previously known location. The
mandatory Host header has been specified, and the Content-Type header
has been correctly set as well ("application/ccmp+xml").
The ConfS, in turn, has handled the request and replied accordingly.
The response (a blueprintResponse message with a set
to a successful value, "200") has been carried as payload of a 200 OK
HTTPS response (message 2.). As before, the Content-Type header has
been correctly set ("application/ccmp+xml").
1. CMCC -> ConfS (HTTPS POST, CCMP request)
------------------------------------------
POST /Xcon/Ccmp HTTP/1.1
Content-Length: 657
Content-Type: application/ccmp+xml
Host: example.com:443
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.0.1 (java 1.5)
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xcon-userid:Alice@example.com
xcon:AudioRoom@example.com
retrieve
2. CMCC <- ConfS (200 to POST, CCMP response)
---------------------------------------------
HTTP/1.1 200 OK
X-Powered-By: Servlet/2.5
Server: Sun GlassFish Communications Server 1.5
Content-Type: application/ccmp+xml;charset=ISO-8859-1
Content-Length: 1652
Date: Thu, 04 Feb 2010 14:47:56 GMT
xcon-userid:Alice@example.com
xcon:AudioRoom@example.com
retrieve
200
success
AudioRoom
2
audio
allow
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confirm
For completeness, the following provides some details of the CCMP
interaction. Despite the simplicity of the request, this flow
provides some relevant information on how CCMP messages are built.
Specifically, both the CCMP request and the CCMP response share a
subset of the message:
o : this element, provided by the CMCC, refers to the
requester by means of his XCON-USERID; except in a few scenarios
(presented in the following sections), this element must always
contain a valid value;
o : this element refers to the target conference object,
according to the request in place;
o : this element specifies the operation the CMCC wants
to perform, according to the specific request type.
Besides those elements, the CMCC (let's say Alice, whose XCON-USERID
is "xcon-userid:Alice@example.com") has also provided an additional
element, . The name of that element varies
according to the request type in which the CMCC is interested. In
this specific scenario, the CMCC was interested in acquiring details
concerning a specific blueprint (identified by its XCON-URI
"xcon:AudioRoom@example.com", as reflected in the provided
target element), and so the request consisted in an empty
element. It will be clearer in the following
sections that different request types may require different elements
and, as a consequence, different content.
Considering the request was a blueprintRequest message, the ConfS has
replied with a blueprintResponse message containing a
element. This element includes a complete dump
of the conference object (compliant with the data model) describing
the requested blueprint.
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Without providing additional details of this interaction, it is worth
noting that this was the example of the simplest CCMP communication
that could take place between a CMCC and a ConfS, a blueprint
request: this scenario will be described in more detail in
Section 5.2.
4.3. Conference Notifications
The XCON framework [RFC5239] identifies several different possible
protocol interactions between a conference server and a conferencing
client. One of those interactions is generically called
"notification protocol" providing a mechanism for all clients
interested in being informed by the server whenever something
relevant happens in a conference. When SIP is used as the call
signaling protocol in a CCMP implementation, the XCON event package
[RFC6502], which extends the SIP event package for conference state
[RFC4575] must be supported. A SIP client uses the SIP SUBSCRIBE
message for the XCON event package to subscribe to notifications
related to a specific conference. A SIP client would receive
notifications describing all the changes to the document via a SIP
NOTIFY message. An example ladder diagram is presented in Figure 2;
in this figure, we assume a CMCC has updated a conference object, and
a previously subscribed SIP client is notified of the update.
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CMCC ConfS UAC
| | |
| | 1. SIP SUBSCRIBE |
| |<--------------------------|
| Handle +--| |
| new | | |
| subscription +->| 2. SIP 200 OK |
| |-------------------------->|
| | |
' ' '
' ' '
| | |
| 3. CCMP (add user) | |
|---------------------->| |
| |--+ Add user |
| | | to conf. |
| |<-+ object |
| 4. CCMP (success) | |
|<----------------------| |
| | 5. SIP NOTIFY (changes) |
| |-------------------------->|
| | 6. SIP 200 OK |
| |<--------------------------|
| | |
' ' '
' ' '
Figure 2: XCON Event Package: SIP Notifications
The detailed flows in this document generically present a
notification, when appropriate, but do not include the SIP messaging
details.
5. Conference Creation
This section provides details associated with the various ways in
which a conference can be created using CCMP and the XCON framework
constructs. As previously mentioned, the details of the media
control, call signaling, and floor control protocols, where
applicable, are annotated in the flows without showing all the
details. This also applies to CCMP, whose flows are related to the
protocol alone, hiding any detail concerning the transport that may
have been used (e.g., HTTPS). However, for clarification purposes,
the first example in Section 5.1 provides the details of the media
control messaging with the standard annotation used throughout the
remainder of this document. In subsequent flows, only this
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annotation (identified by lowercase letters) is included, and the
reader is encouraged to refer to the call flows in the relevant
documents for details about the other protocols. The annotations for
the call signaling are on the left side of the conference server
vertical bar, and those for the media control messaging are on the
right side.
5.1. Basic Conference Creation
The simplest manner in which a conference can be created is
accomplished by the client sending a confRequest message with the
element set to "create" as the only parameter to the
conference server, together with the associated with the
requesting client itself. This results in the creation of a default
conference, with an XCON-URI in the form of the element,
the XCON-USERID in the form of the element (the same one
already present in the request), and the data for the conference
object in the parameter all returned in the confResponse
message. This example also adds the issuing user to the conference
upon creation with the 'method' attribute in the child
element of set to "dial-out".
The specific data for the conference object is returned in the
confResponse message in the parameter. This allows the
client (with the appropriate authorization) to manipulate these data
and add additional participants to the conference, as well as change
the data during the conference. In addition, the client may
distribute the conferencing information to other participants
allowing them to join, the details of which are provided in
additional flows. Please notice that, according to the CCMP
specification, the return of the new conference data in the
element is not mandatory: if the parameter of
is not included in the successful confResponse/create message, a
subsequent confRequest/retrieve message of the returned
can be triggered to provide the requesting client with the detailed
conference description.
Clients that are not XCON-aware can join the conference using a
specific signaling interface such as SIP [RFC3261] (using the
signaling interface to the conference focus as described in
[RFC4579]), or other supported signaling protocols, being XCON-
agnostic with respect to them. However, these details are not shown
in the message flows. The message flows in this document identify
the point in the message flows at which this signaling occurs via the
lowercase letter items (i.e., (a)...(x)) along with the appropriate
text for the processing done by the conference server.
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As previously described, this example also shows how the conferencing
system may make use of other standard protocol components for
complete functionality. An example of that is the media control
framework [RFC5567], which allows the conferencing system to
configure conference mixes, Interactive Voice Response (IVR) dialogs,
and all sorts of media-related interactions an application like this
may need. In order to provide the reader with some insight on these
interactions, the conference server in this example also configures
and starts a mixer via a media control channel as soon as the
conference is created (transactions A1 and A2), and attaches clients
to it when necessary (e.g., when CMCC1 joins the conference by means
of SIP signaling, its media channels are attached to the media server
(MS) in B1/B2). Note, that the media control interfaces are NOT
shown in the remaining call flows in this document but rather follow
the same annotation as with the SIP signaling such that (b)
correlates with the A1 and A2 transactions and (d) correlates with
the B1 and B2 transactions.
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CMCC1 CMCC2 CMCCx ConfS MS
| | | | |
|(1)confRequest(confUserID, create) | |
|-------------------------------------->| |
| | (a)Create +---| |
| | |Conf | | |
| | |Object | | |
| | |& IDs +-->| |
| | | | A1. CONTROL |
| | | |+++++++++++>>|
| | | |(create conf)|--+ (b)
| | | | | | create
| | | | | | conf and
| | | | A2. 200 OK |<-+ its ID
| | | |<<+++++++++++|
| | | |(confid=Y) |
|(2)confResponse(confUserID,confObjID, | |
| create, 200, success, | |
| version, confInfo) | |
|<--------------------------------------| |
| | | | |
| | (c) Focus +---| |
| | sets up | | |
| | signaling | | |
| | to CMCC1 +-->| |
| | | | |
| | | | B1. CONTROL |
| | | |+++++++++++>>|
| | | | (join CMCC1 |
| | | | <->confY) |
| | | | |
| | | | |--+(d) join
| | | | | | CMCC1 &
| | | | B2.200 OK |<-+ conf Y
| | | |<<+++++++++++|
| | | | |
|<<#################################################>>|
| Now the CMCC1 is mixed in the conference |
|<<#################################################>>|
| | | | |
|******CMCC1 may then manipulate conference data *****|
|****** and add addt'l users, etc. | *****|
' ' ' ' '
' ' ' ' '
' ' ' ' '
Figure 3: Create Basic Conference - Complete flow
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1. confRequest/create message (Alice creates a default conference)
xcon-userid:Alice@example.com
create
2. confResponse/create message ("success", created conference
object returned)
xcon-userid:Alice@example.com
xcon:8977794@example.com
create
200
success
1
Default conference initiated by Alice
xcon:8977794@example.com
Conference XCON-URI
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10
audio
false
allow
Figure 4: Create Basic Conference Detailed Messaging
5.2. Conference Creation Using Blueprints
The previous example showed the creation of a new conference using
default values. This means the client provided no information about
how she wanted the conference to be created. The XCON framework (and
CCMP as a consequence) allows for the implementation of templates.
These templates are called "conference blueprints" and are basically
conference objects with predefined settings. This means that a
client might get a list of blueprints, choose the one that most fits
his needs, and use the chosen blueprint to create a new conference.
Figure 5 provides an example of one client, Alice, discovering the
conference blueprints available for a particular conferencing system
and creating a conference based on the desired blueprint. In
particular, Alice is interested in those blueprints suitable to
represent a video conference, i.e., a conference in which both audio
and video are available, so she makes use of the filter mechanism
provided by CCMP to make a selective blueprints retrieve request.
This results in three distinct CCMP transactions.
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CMCC Alice ConfS
| |
| (1) blueprintsRequest |
| (confUserID,xpathFilter) |
|------------------------------>|
| |
| (2) blueprintsResponse |
| (confUserID, |
| 200, success, |
| blueprintsInfo) |
| |
|<------------------------------|
| |
|--+ |
| | choose preferred |
| | blueprint from the |
| | list (blueprintName) |
|<-+ |
| |
| (3) blueprintRequest |
| (confUserID,confObjID, |
| retrieve) |
|------------------------------>|
| |
| 4) blueprintResponse |
| (confUserID,confObjID,|
| retrieve, 200, |
| success, confInfo) |
|<------------------------------|
| |
| (5) confRequest(confUserID, |
| confObjID,create) |
|------------------------------>|
| |
| (a)Create +---|
| Conf | |
| Object | |
| & IDs +-->|
| |--+ (b) MS
| | | creates
| | | conf and
| |<-+ its ID
| | (confid=Y)
|(6) confResponse |
| (confUserID, confObjID*, |
| create, 200, success) |
|<------------------------------|
| |
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| |
| |
' '
' '
Figure 5: Client Creation of Conference Using Blueprints
1. Alice first sends a blueprintsRequest message to the conference
server identified by the conference server discovery process.
This request contains the set to the XCON-USERID of
the user issuing the request (in this case, the one belonging to
Alice) and the element by which Alice specifies she
desires to obtain only blueprints providing support for both
audio and video: for this purpose, the xpath query contained in
this field is: "/conference-info[conference-description/
available-media/entry/type='audio' and conference-description/
available-media/entry/type='video']". Upon receipt of the
blueprintsRequest message, the conference server would first
ensure, on the basis of the parameter, that Alice
has the appropriate authority based on system policies to receive
the requested kind of blueprints supported by that system.
2. All blueprints that Alice is authorized to use are returned in a
blueprintsResponse message in the element.
3. Upon receipt of the blueprintsResponse message containing the
blueprints, Alice determines which blueprint to use for the
conference to be created. Alice sends a blueprintRequest message
to get the specific blueprint as identified by the .
4. The conference server returns the details associated with the
specific blueprint identified by the in the
element within the blueprintResponse message.
5. Alice finally sends a confRequest message with a "create"
to the conference server to create a conference
reservation cloning the chosen blueprint. This is achieved by
writing the blueprint's XCON-URI in the parameter.
6. Upon receipt of the confRequest/create message, the conference
server uses the received blueprint to clone a conference,
allocating a new XCON-URI (called "confObjID*" in the example).
The conference server then sends a confResponse message including
the new "confObjID*" associated with the newly created conference
instance as the value of the parameter. Upon receipt
of the confResponse message, Alice can now add other users to the
conference.
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1. blueprintsRequest message (Alice requires the list of the
available blueprints with video support)
xcon-userid:Alice@example.com
/conference-info[conference-description/
available-media/entry/type='audio'
and
conference-description/available-media/entry/type='video']
2. blueprintsResponse message (the server provides a
descriptions of the available blueprints
fitting Alice's request)
xcon-userid:Alice@example.com
200
success
xcon:VideoRoom@example.com
VideoRoom
Video Room:
conference room with public access,
where both audio and video are available,
4 users can talk and be seen at the same time,
and the floor requests are automatically accepted.
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xcon:VideoConference1@example.com
VideoConference1
Public Video Conference: conference
where both audio and video are available,
only one user can talk
3. blueprintRequest/retrieve message (Alice wants the
"VideoRoom" blueprint)
xcon-userid:Alice@example.com
xcon:VideoRoom@example.com
retrieve
4. blueprintResponse/retrieve message ("VideoRoom"
conference object returned)
xcon-userid:Alice@example.com
xcon:VideoRoom@example.com
retrieve
200
success
VideoRoom
Barnes, et al. Informational [Page 20]
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4
audio
video
allow
confirm
audioLabel
videoLabel
5. confRequest/create message (Alice clones the "VideoRoom" blueprint)
xcon-userid:Alice@example.com
xcon:VideoRoom@example.com
create
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6. confResponse/create message (cloned conference
object returned)
xcon-userid:Alice@example.com
xcon:8977794@example.com
create
200
success
1
New conference by Alice cloned from VideoRoom
xcon:8977794@example.com
conference xcon-uri
8601
10
audio
video
allow
Barnes, et al. Informational [Page 22]
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confirm
11
12
Figure 6: Create Conference (Blueprint) Detailed Messaging
5.3. Conference Creation Using User-Provided Conference Information
A conference can also be created by the client sending a confRequest
message with the "create" , along with the desired data in
the form of the element for the conference to be created.
The request also includes the set to the XCON-USERID of
the requesting entity.
This approach allows for a client (in this example Alice) to
completely describe what the conference object should look like,
without relying on defaults or blueprints; for example, which media
should be available, the topic, the users allowed to join, any
scheduling-related information, and so on. This can be done by
providing, in the creation request, a full conference object for the
server to parse.
This parameter must comply with the data model
specification. This means that the 'entity' attribute is mandatory
and cannot be missing in the document. However, in this example, the
client is actually requesting the creation of a new conference, which
doesn't exist yet, so the 'entity' attribute is unknown. As
discussed in Section 4.1, CCMP allows for the use of a wildcard
placeholder. This placeholder ("xcon:AUTO_GENERATE_1@example.com" in
the example) is only to ensure the element is compliant
with the data model and would subsequently be replaced by the
conference server with the actual value. Thus, when the conference
server actually creates the conference, a valid value for the
'entity' attribute is created for it as well, which takes the place
Barnes, et al. Informational [Page 23]
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of the wildcard value when the actual conference object provided by
the client is populated.
To give a flavor of what could be added to the conference object, we
assume Alice is also interested in providing scheduling-related
information. So, in this example, Alice also specifies by the
element included in the that the
conference she wants to create has to occur on a certain date
spanning from a certain start time to a certain stop time and has to
be replicated weekly.
Moreover, Alice indicates by means of the
element that at the start time Bob, Carol, and herself have to be
called by the conferencing system to join the conference (in fact,
for each field corresponding to one of the aforementioned
clients, the 'method' attribute is set to "dial-out").
Once Alice has prepared the element and sent it as part of
her request to the server, if the conferencing system can support
that specific type of conference (capabilities, etc.), then the
request results in the creation of a conference. We assume the
request has been successful, and as a consequence, the XCON-URI in
the form of the parameter and the XCON-USERID in the form
of the parameter (again, the same as the requesting
entity) are returned in the confResponse message.
In this example, the created conference object is not returned in the
successful confResponse message in the parameter.
Nevertheless, Alice could still retrieve the actual conference object
by issuing a confRequest message with a "retrieve" on the
XCON-URI returned in the of the previous response. Such
a request would show how, as described at the beginning of this
section, the 'entity' attribute of the conference object in the
field is replaced with the actual information (i.e.,
"xcon:6845432@example.com").
Barnes, et al. Informational [Page 24]
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Alice Bob Carol ConfS
| | | |
| | | |
|(1)confRequest(confUserID, | |
| create, confInfo) | |
| | | |
|-------------------------------------->|
| | | |
| | (a)Create +---|
| | |Conf | |
| | |Object | |
| | |& IDs +-->|
| | | |--+ (b) MS
| | | | | creates
| | | | | conf and
| | | |<-+ its ID
| | | | (confid=Y)
|(2)confResponse(confUserID,| |
| confObjID, create, | |
| 200, success, version) |
|<--------------------------------------|
| | | |
===========================================
... ... ... ...
========== START TIME OCCURS ==============
| | (c) Focus +---|
| | sets up | |
| | signaling | |
| | to Alice +-->|
| | | |
| | | |--+(d) MS joins
| | | | | Alice &
| | | |<-+ conf Y
| | | |
| | | |
|<<###################################>>|
| Alice is mixed in the conference |
|<<###################################>>|
| | | |
| | (e)Focus +---|
| | sets up | |
| | signaling | |
| | to Bob | |
| | | +-->|
| | | |
| | | |--+(f)MS joins
| | | | | Bob &
| | | |<-+ conf Y
Barnes, et al. Informational [Page 25]
RFC 6504 CCMP Call Flow Examples March 2012
| | | |
| |<<###################>>|
| | Bob is mixed too |
| |<<###################>>|
| | | |
| | (g )Focus +---|
| | sets up | |
| | signaling | |
| | to Carol | |
| | CMCCx +-->|
| | | |
| | | |--+(h)MS joins
| | | | | CMCCx &
| | | |<-+ conf Y
| | | |
| | |<<#######>>|
| | |Carol mixed|
| | |<<#######>>|
| | | |
| | | |
| | | |
|<***All parties connected to conf Y***>|
| | | |
| | | |
' ' ' '
' ' ' '
' ' ' '
Figure 7: Create Basic Conference from User-Provided Conference Info
1. confRequest/create message (Alice proposes a conference object
to be created)
xcon-userid:Alice@example.com
create
Dial-out conference initiated by Alice
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10
audio
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Mozilla.org/NONSGML
Mozilla Calendar V1.0//EN
BEGIN:VEVENT
DTSTAMP: 20100127T140728Z
UID: 20100127T140728Z-345FDA-alice@example.com
ORGANIZER:MAILTO:alice@example.com
DTSTART:20100127T143000Z
RRULE:FREQ=WEEKLY
DTEND: 20100127T163000Z
END:VEVENT
END:VCALENDAR
2010-01-27T14:29:00Z
2010-01-27T16:31:00Z
2010-01-27T15:30:00Z
allow
Barnes, et al. Informational [Page 27]
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2. confResponse/create message ("200", "success")
xcon-userid:Alice@example.com
xcon:6845432@example.com
create
200
success
1
Figure 8: Create Basic Conference Detailed Messaging
5.4. Cloning an Existing Conference
A client can also create another conference by cloning an existing
conference, such as an active conference or conference reservation.
This approach can be seen as a logical extension of the creation of a
new conference using a blueprint: the difference is that, instead of
cloning the predefined settings listed in a blueprint, the settings
of an existing conference would be cloned.
In this example, the client sends a confRequest message with the
"create" , along with her XCON-USERID in the
element and the XCON-URI of the conference from which a new
conference is to be cloned in the element.
An example of how a client can create a conference based on a
blueprint is provided in Section 5.2. The manner by which a client
in this example might learn about a conference reservation or active
conferences is similar to the first step in the blueprint example,
with the exception of querying for different types of conference
Barnes, et al. Informational [Page 28]
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objects supported by the specific conferencing system. For instance,
in this example, the client clones a conference reservation (i.e., an
inactive conference).
If the conferencing system can support a new instance of the specific
type of conference (capabilities, etc.), then the request results in
the creation of a conference, with an XCON-URI in the form of a new
value in the parameter to reflect the newly cloned
conference object returned in the confResponse message.
Alice ConfS
| |
|(1)confRequest(confUserID, |
| confObjID, create) |
|------------------------------>|
| (a)Create +---|
| Conf | |
| Object | |
| & IDs +-->|
| |--+ (b) MS
| | | creates
| | | conf and
| |<-+ its ID
| | (confid=Y)
| |
|(2)confResponse(confUserID, |
| confObjID*,create, |
| 200, success, |
| version, confInfo) |
| |
|<------------------------------|
| |
' '
Figure 9: Create Basic Conference - Clone
1. Alice, a conferencing system client, sends a confRequest message
to clone a conference based on an existing conference
reservation. Alice indicates this conference should be cloned
from the specified parent conference represented by the XCON-URI
in the provided in the request.
2. Upon receipt of the confRequest message containing a "create"
and the aforementioned XCON-URI in the ,
the conference server ensures that such received XCON-URI is
valid. The conference server determines the appropriate read/
write access of any users to be added to a conference based on
this XCON-URI (using membership, roles, etc.). The conference
Barnes, et al. Informational [Page 29]
RFC 6504 CCMP Call Flow Examples March 2012
server uses the received to clone a conference
reservation. The conference server also reserves or allocates a
new XCON-URI (called "confObjID*" in Figure 9) to be used for the
cloned conference object. This new identifier is, of course,
different from the one associated with the conference to be
cloned, since it represents a different conference object. Any
subsequent protocol requests from any of the members of the
conference must use this new identifier. The conference server
maintains the mapping between this conference ID and the parent
conference object ID associated with the reservation through the
conference instance, and this mapping is explicitly addressed
through the element of the in the new conference object.
1. confRequest/create message (Alice clones an existing conference)
xcon-userid:Alice@example.com
xcon:6845432@example.com
create
2. confResponse/create message (created conference
object returned)
xcon-userid:Alice@example.com
xcon:8977794@example.com
create
200
success
1
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RFC 6504 CCMP Call Flow Examples March 2012
New conference by Alice cloned from 6845432
10
audio
xcon:6845432@example.com
allow
confirm
11
Figure 10: Create Basic Conference (Clone) Detailed Messaging
6. Conference Users Scenarios and Examples
Section 5 showed examples describing the several different ways a
conference might be created using CCMP. This section focuses on
user-related scenarios, i.e., typical scenarios that may occur during
Barnes, et al. Informational [Page 31]
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the lifetime of a conference, like adding new users and handling
their media. The following scenarios are based on those documented
in the XCON framework. The examples assume that a conference has
already been correctly established, with media, if applicable, per
one of the examples in Section 5.
6.1. Adding a Party
In this example, Alice wants to add Bob to an established conference.
In the following example we assume Bob is a new user of the system,
which means Alice also needs to provide some details about him. In
fact, the case of Bob already present as a user in the conferencing
system is much easier to address, and will be discussed later.
Alice Bob
CMCC1 CMCC2 CMCCx ConfS
| | | |
|(1) userRequest(confUserID,| |
| confObjID, create, | |
| userInfo) | | |
|-------------------------------------->|
| | | |
| | (a) Create +---|
| | | Bob | |
| | | as a | |
| | | user +-->|
| | | |
|(2) userResponse(confUserID, confObjID |
| create, 200, success, userInfo) |
|<--------------------------------------|
| | | |
| | | (b) Focus |
| | | sets up |
| | | signaling |
| | | to Bob |
| |<----------------------|
| | | |
| | | (c) Notify|
| | | ("Bob just|
| | | joined") |
| | |<----------|
| | | |
' ' ' '
' ' ' '
' ' ' '
Figure 11: Client Manipulation of Conference - Add a Party
Barnes, et al. Informational [Page 32]
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1. Alice sends a userRequest message with an operation of "create"
to add Bob to the specific conference as identified by the XCON-
URI in the . The "create" also makes sure
that Bob is created as a user in the whole conferencing system.
This is done by adding in the request a element
describing Bob as a user. This is needed in order to let the
conferencing system be aware of Bob's characteristics. In case
Bob was already a registered user, Alice would just have
referenced him through his XCON-USERID in the 'entity' attribute
of the field, without providing additional data. In
fact, that data (including, for instance, Bob's SIP-URI to be
used subsequently for dial-out) would be obtained by referencing
the extant registration. The conference server ensures that
Alice has the appropriate authority based on the policies
associated with that specific conference object to perform the
operation. As mentioned before, a new XCON-USERID is created for
Bob, and the is used to update the conference object
accordingly. As already seen in Section 5.3, a placeholder
wildcard ("xcon-userid:AUTO_GENERATE_1@example.com" in the CCMP
messages below) is used for the 'entity' attribute of the
element, to be replaced by the actual XCON-USERID
later;
2. Bob is successfully added to the conference object, and an XCON-
USERID is allocated for him ("xcon-userid:Bob@example.com"); this
identifier is reported in the response as the value of the
'entity' attribute of the returned ;
3. In the presented example, the call signaling to add Bob to the
conference is instigated through the focus as well. As noted
previously, this is implementation specific. In fact, a
conferencing system may accomplish different actions after the
user creation, just as it may do nothing at all. Among the
possible actions, for instance, Bob may be added as a
element to the element, whose joining
'method' may be either "dial-in" or "dial-out". Besides, out-of-
band notification mechanisms may be involved as well, e.g., to
notify Bob via mail of the new conference, including details as
the date, password, expected participants, and so on (see
Section 4.3).
Once Bob has been successfully added to the specified conference,
per updates to the state, and depending upon the policies, other
participants (including Bob himself) may be notified of the
addition of Bob to the conference via the conference notification
service in use.
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RFC 6504 CCMP Call Flow Examples March 2012
1. userRequest/create message (Alice adds Bob)
xcon-userid:Alice@example.com
xcon:8977878@example.com
create
Bob
mailto:bob.depippis@example.com
Bob's email
Bob's laptop
2. userResponse/create message (a new XCON-USERID is
created for Bob and he is added to the conference)
xcon-userid:Alice@example.com
xcon:8977878@example.com
create
200
success
10
Bob
Barnes, et al. Informational [Page 34]
RFC 6504 CCMP Call Flow Examples March 2012
mailto:bob.depippis@example.com
Bob's email
Bob's laptop
Figure 12: Add Party Message Details
6.2. Muting a Party
This section provides an example of the muting of a party in an
active conference. We assume that the user to mute has already been
added to the conference. The document only addresses muting and not
unmuting, since the latter would involve an almost identical CCMP
message flow anyway. However, if any external floor control is
involved, whether a particular conferencing client can actually mute/
unmute itself must be considered by the conferencing system.
Please notice that interaction between CCMP and floor control
should be carefully considered. In fact, handling CCMP- and BFCP-
based media control has to be considered as multiple layers: that
is, a participant may have the BFCP floor granted, but be muted by
means of CCMP. If so, he would still be muted in the conference,
and would only be unmuted if both the protocols allowed for this.
Figure 13 provides an example of one client, Alice, impacting the
media state of another client, Bob. This example assumes an
established conference. In this example, Alice, who is the moderator
of the conference, wants to mute Bob on a medium-sized multi-party
conference, as his device is not muted (and he's obviously not
listening to the call) and background noise in his office environment
is disruptive to the conference. BFCP floor control is assumed not
to be involved.
Muting can be accomplished using the control element
associated with the target user's audio, in which case the conference
server must update the settings associated with the user's media
streams. Muting/unmuting can also be accomplished by directly
modifying the settings related to the target user's media streams,
which is the approach shown in this example. Specifically, Bob's
is updated by modifying the element in the
Barnes, et al. Informational [Page 35]
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part related to audio information, identified by the 'id'
attribute. The modification consists in setting the audio
to "recvonly", in case of muting.
Alice Bob
CMCC1 CMCC2 CMCCx ConfS MS
| | | | |
|(1) userRequest(subject, | | |
| confUserID,confObjID, | | |
| update,userInfo) | | |
| | | | |
|--------------------------------------->| |
| | | | Mute Bob |
| | | |----------------->|
| | | | 200 OK |
| | | |<-----------------|
| | | | |
| |<====== XXX Bob excluded from mix XXX ====>|
| | | | |
| | (a) Update +---| |
| | Bob in | | |
| | data model | | |
| | (muted) +-->| |
| | | | |
| (2)userResponse(confUserID,confObjID, | |
| update,200,success,version) | |
|<---------------------------------------| |
| | | | |
| | | (b) Notify | |
| | | ("Bob is | |
| | | muted") | |
| | |<-----------| |
| | | | |
' ' ' ' '
' ' ' ' '
' ' ' ' '
Figure 13: Client Manipulation of Conference - Mute a Party
1. Alice sends a userRequest message with an "update"
and the with the field in the element
for Bob's set to "revconly". In order to authenticate
herself, Alice provides in the request parameter her
registration credentials (i.e., username and password). The
parameter is an optional one: its use can be systematic
whenever the conference server envisages to authenticate each
Barnes, et al. Informational [Page 36]
RFC 6504 CCMP Call Flow Examples March 2012
requester. In such cases, if the client does not provide the
required authentication information, the conferencing server
answers with a CCMP "authenticationRequired" ,
indicating that the request cannot be processed without including
the proper parameter. The conference server ensures
that Alice has the appropriate authority based on the policies
associated with that specific conference object to perform the
operation. It recognizes that Alice is allowed to request the
specified modification, since she is moderator of the target
conference, and updates the in the conference object
reflecting that Bob's media is not to be mixed with the
conference media. If the conference server relies on a remote
media server for its multimedia functionality, it subsequently
changes Bob's media profile accordingly by means of the related
protocol interaction with the MS. An example describing a
possible way of dealing with such a situation using the media
server control architecture [RFC5567] is described in Figure 31,
"Simple Bridging: Framework Transactions (2)", in [CALL-FLOWS].
2. A userResponse message with a "200" ("success")
is then sent to Alice. Depending upon the policies, the
conference server may notify other participants (including Bob)
of this update via any conference notification service that may
be in use.
1. userRequest/update message (Alice mutes Bob)
Alice83
13011983
xcon-userid:Alice@example.com
xcon:8977878@example.com
update
123
recvonly
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2. userResponse/update message (Bob has been muted)
xcon-userid:Alice@example.com
xcon:8977878@example.com
update
200
success
7
Figure 14: Mute Message Details
6.3. Conference Announcements and Recordings
This section deals with features that are typically required in a
conferencing system, such as public announcements (e.g., to notify
vocally that a new user joined a conference) and name recording.
While this is not strictly CCMP-related (the CCMP signaling is
actually the same as the one seen in Section 6.1), it is an
interesting scenario to address to see how several components of an
XCON-compliant architecture interact with each other to make it
happen.
In this example, as shown in Figure 15, Alice is joining Bob's
conference that requires that she first enter a passcode. After
successfully entering the passcode, an announcement prompts Alice to
speak her name so it can be recorded. When Alice is added to the
active conference, the recording is played back to all the existing
participants. A very similar example is presented in Figure 33 of
[CALL-FLOWS].
Barnes, et al. Informational [Page 38]
RFC 6504 CCMP Call Flow Examples March 2012
CMCC Alice ConfS MS
| | |
|(1)userRequest(confObjID, | |
| create,userInfo) | |
|--------------------------->| |
| |--+ Alice is |
| | | new in the |
| |<-+ system (create |
| | confUserID) |
| ConfS handles +--| |
| SIP signaling | | |
| (Alice<->ConfS<->MS) +->| |
| | |
| |--+ A password is |
| | | required for |
| |<-+ that conference |
| | |
| | Request IVR menu (PIN) |
| |--------------------------->|
| | |
|<========= MS gets PIN from Alice through DTMF =========>|
| | |
| | Provided PIN is... |
| |<---------------------------|
| Check +--| |
| PIN | | |
| +->| |
| |--+ Alice must |
| | | record her |
| |<-+ name |
| | |
| | Request name recording |
| |--------------------------->|
| | |
|<========= MS records Alice's audio RTP (name) =========>|
| | |
| | Audio recording |
| |<---------------------------|
| Complete +--| |
| creation | | |
| of Alice +->| |
Barnes, et al. Informational [Page 39]
RFC 6504 CCMP Call Flow Examples March 2012
| | |
| | |
| (2)userResponse(confUserID,| |
| confObjID,create,200,| |
| success,version) | |
|<---------------------------| |
| | |
' ' '
Figure 15: Recording and Announcements
1. Upon receipt of the userRequest message from Alice to be added to
Bob's conference, the conference server determines that a
password is required for this specific conference. Thus, an
announcement asking Alice to enter the password is sent back.
This may be achieved by means of typical IVR functionality. Once
Alice enters the password, it is validated against the policies
associated with Bob's active conference. The conference server
then connects to a server that prompts and records Alice's name.
The conference server must also determine whether Alice is
already a user of this conferencing system or whether she is a
new user. In this case, Alice is a new user for this
conferencing system, so a new XCON-USERID is created for Alice.
Based upon the contact information provided by Alice, the call
signaling to add Alice to the conference is instigated through
the focus.
2. The conference server sends Alice a userResponse message that
includes in the the XCON-USERID assigned by the
conferencing system to her. This would allow Alice to later
perform operations on the conference (if she were to have the
appropriate policies), including registering for event
notifications associated with the conference. Once the call
signaling indicates that Alice has been successfully added to the
specific conference, per updates to the state, and depending upon
the policies, other participants (e.g., Bob) are notified of the
addition of Alice to the conference via the conference
notification service and an announcement is provided to all the
participants indicating that Alice has joined the conference.
1. userRequest/create message (a new conferencing system client,
Alice, enters Bob's conference)
Barnes, et al. Informational [Page 40]
RFC 6504 CCMP Call Flow Examples March 2012
xcon:bobConf@example.com
create
mailto:Alice83@example.com
email
2. userResponse/create message (Alice provided with a new XCON-USERID
and added to the conference)
xcon-userid:Alice@example.com
xcon:bobConf@example.com
create
200
success
5
Figure 16: Announcement Messaging Details
6.4. Monitoring for DTMF
Conferencing systems also often need the capability to monitor for
dual-tone multi-frequency (DTMF) from each individual participant.
This would typically be used to enter the identifier and/or access
code for joining a specific conference. This feature is also often
Barnes, et al. Informational [Page 41]
RFC 6504 CCMP Call Flow Examples March 2012
exploited to achieve interaction between participants and the
conferencing system for non-XCON-aware user agents (e.g., using DTMF
tones to get muted/unmuted).
An example of DTMF monitoring, within the context of the framework
elements, is shown in Figure 15. The media control architecture and
protocols [RFC5567] can be used by the conference server for all the
DTMF interactions. Examples for DTMF interception in conference
instances are presented in [CALL-FLOWS].
6.5. Entering a Password-Protected Conference
Some conferences may require a password to be provided by a user who
wants to manipulate the conference objects (e.g., join, update,
delete) via CCMP. In this case, a password would be included in the
element in the appropriate
entry of the conference data model. Such password must be then
included in the field in the CCMP request
addressed to that conference.
In the following example, Alice, a conferencing system client,
attempts to join a password-protected conference.
1. Alice sends a userRequest message with a "create" to
add herself in the conference with XCON-URI
"xcon:8977777@example.com" (written in the
parameter). Alice provides her XCON-USERID via the
field of the userRequest message and leaves out the
one (first-party join). In this first attempt, she doesn't
insert any password parameter.
2. Upon receipt the userRequest/create message, the conference
server detects that the indicated conference is not joinable
without providing the appropriate passcode. A userResponse
message with a "423" ("conference password
required") is returned to Alice to indicate that her join has
been refused and that she has to resend her request including the
appropriate conference password in order to participate.
3. After getting the passcode through out-of-band mechanisms, Alice
provides it in the proper request field of
a new userRequest/create message and sends the updated request
back to the server.
4. The conference server checks the provided password and then adds
Alice to the protected conference. After that, a userResponse
message with a "200" ("success") is sent to
Alice.
Barnes, et al. Informational [Page 42]
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1. userRequest/create message (Alice tries to enter the conference
without providing the password)
xcon-userid:Alice@example.com
xcon:8977794@example.com
create
2. userResponse/create message ("423", "conference password required")
xcon-userid:Alice@example.com
xcon:8977794@example.com
create
423
conference password required
3. userRequest/create message (Alice provides the password)
xcon-userid:Alice@example.com
xcon:8977794@example.com
create
8601
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4. userResponse/create message
(Alice has been added to the conference)
xcon-userid:Alice@example.com
xcon:8977794@example.com
create
200
success
10
Figure 17: Password-Protected Conference Join Messages Details
7. Sidebars Scenarios and Examples
While creating conferences and manipulating users and their media are
sufficient for many scenarios, there may be cases when more complex
management is needed.
In fact, a feature typically required in conferencing systems is the
ability to create sidebars. A sidebar is basically a child
conference that usually includes a subset of the participants of the
parent conference and a subset of its media as well. Sidebars are
typically required whenever some of the participants in a conference
want a private discussion, without interfering with the main
conference.
This section deals with some typical scenarios using a sidebar, like
whispering, private messaging, and coaching scenarios. The first
subsections present some examples of how a generic sidebar can be
created, configured, and managed.
Barnes, et al. Informational [Page 44]
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7.1. Internal Sidebar
Figure 18 provides an example of one client, Alice, involved in an
active conference with Bob and Carol. Alice wants to create a
sidebar to have a side discussion with Bob while still viewing the
video associated with the main conference. Alternatively, the audio
from the main conference could be maintained at a reduced volume.
Alice initiates the sidebar by sending a request to the ConfS to
create a conference reservation based upon the active conference
object. Alice and Bob would remain on the roster of the main
conference, such that other participants could be aware of their
participation in the main conference, while an internal-sidebar
conference is occurring. Besides, Bob decides that he is not
interested in still receiving the conference audio in background (not
even at a lower volume as Alice configured) and so modifies the
sidebar in order to make that stream inactive for him.
Alice Bob ConfS
| | |
|(1) sidebarByValRequest(confUserID, |
| confObjID,create) |
|--------------------------------------------->|
| | |
| | (a) Create +---|
| | sidebar-by-val | |
| | (new conf obj | |
| | cloned from +-->|
| | confObjID) | Sidebar now has
| | | id confObjID*
|(2) sidebarByValResponse(confUserID, | (parent mapping
| (confObjID*,create,200,success, | conf<->sidebar)
| version,sidebarByValInfo) |
|<---------------------------------------------|
| | |
|(3) sidebarByValRequest |
| (confUserID, confObjID*, |
| update,sidebarByValInfo) |
|--------------------------------------------->|
| | |
Barnes, et al. Informational [Page 45]
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| | (b) Update +---|
| | sidebar-by-val | |
| | (media, users | |
| | etc.) +-->|
| | | Sidebar is
| | | modified
|(4) sidebarByValResponse(confUserID, |
| confObjID*, update, |
| 200, success, version) |
|<---------------------------------------------|
| | |
| |(5) userRequest |
| | (confUserID', |
| | confObjID*, |
| | update,userInfo)|
| |---------------------->|
| | |
| | (c) Update +---|
| | user settings | |
| | (Bob's media) | |
| | +-->|
| | | Sidebar is modified
| | | (original audio
| | | inactive for Bob)
| |(6) userResponse |
| | (confUserID', |
| | confObjID*, |
| | update, 200, |
| | success,version) |
| |<----------------------|
| | |
' ' '
' ' '
' ' '
Figure 18: Client Creation of a Sidebar Conference
1. Upon receipt of CCMP sidebarByValRequest message to create a new
sidebar based upon the conference whose XCON-URI is in the
received in the request, the conference server uses
such XCON-URI to clone a conference reservation for the sidebar.
The sidebar reservation is NOT independent of the active main
conference (i.e., parent). The conference server also allocates
a new XCON-URI ("confObjID*" in Figure 18) for that sidebar to be
used for any subsequent protocol requests from any of the members
of the conference. The new XCON-URI is returned in the response
message parameter.
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2. The relationship information is provided in the
sidebarByValResponse message, specifically in the element. A dump of the complete representation of the
main/parent conference is provided below as well to show how the
cloning process for the creation of the sidebar could take place.
3. Upon receipt of the sidebarByValResponse message to reserve the
conference, Alice can now create an active conference using that
reservation or create additional reservations based upon the
existing reservations. In this example, Alice wants only Bob to
be involved in the sidebar; thus, she manipulates the membership
so that only the two of them appear in the
section. Alice also wants both audio and video from the original
conference to be available in the sidebar. For what concerns the
media belonging to the sidebar itself, Alice wants the audio to
be restricted to the participants in the sidebar (that is, Bob
and herself). Additionally, Alice manipulates the media values
to receive the audio from the main conference at a reduced
volume, so that the communication between her and Bob isn't
affected. Alice sends a sidebarByValRequest message with an
operation of "update" along with the
containing the aforementioned sidebar modifications.
4. Upon receipt of the sidebarByValRequest message to update the
sidebar reservation, the conference server ensures that Alice has
the appropriate authority based on the policies associated with
that specific conference object to perform the operation. The
conference server must also validate the updated information in
the reservation, ensuring that a member like Bob is already a
user of this conference server. Once the data for the conference
identified by the is updated, the conference server
sends a sidebarByValResponse message to Alice. Depending upon
the policies, the initiator of the request (i.e., Alice) and the
participants in the sidebar (i.e., Bob) may be notified of his
addition to the sidebar via the conference notification service.
5. At this point, Bob sends a userRequest message to the conference
server with an operation of "update" to completely disable the
background audio from the parent conference, since it prevents
him from understanding what Alice says in the sidebar.
6. Notice that Bob's request only changes the media perspective for
Bob. Alice keeps on receiving both the audio from Bob and the
background from the parent conference. This request may be
relayed by the conference server to the media server handling the
mixing, if present. Upon completion of the change, the
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conference server sends a userResponse message to Bob. Depending
upon the policies, the initiator of the request (i.e., Bob) and
the participants in the sidebar (i.e., Alice) may be notified of
this change via the conference notification service.
The following conference object represents the conference in which
the sidebar is to be created. It will be used by the conference
server to create the new conference object associated with the
sidebar.
MAIN CONFERENCE
sip:8977878@example.com
conference sip uri
main conference audio
audio
sendrecv
main conference video
video
sendrecv
single-view
true
Alice
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123
sendrecv
456
sendrecv
Bob
123
sendrecv
456
sendrecv
Carol
123
sendrecv
456
sendrecv
Figure 19: Conference with Alice, Bob, and Carol
The sidebar creation happens through a cloning of the parent
conference. Once the sidebar is created, an update request makes
sure that the sidebar is customized as needed. The following
protocol dump makes the process clearer.
Barnes, et al. Informational [Page 49]
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1. sidebarByValRequest/create message (Alice creates an
internal sidebar)
xcon-userid:Alice@example.com
xcon:8977878@example.com
create
2. sidebarByValResponse/create message (sidebar returned)
xcon-userid:Alice@example.com
xcon:8974545@example.com
create
200
success
1
SIDEBAR CONFERENCE registered by Alice
main conference audio
audio
sendrecv
main conference video
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video
sendrecv
false
xcon:8977878@example.com
3. sidebarByValRequest/update message (Alice updates the
created sidebar)
xcon-userid:Alice@example.com
xcon:8974545@example.com
update
private sidebar Alice - Bob
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main conference audio
audio
recvonly
-60
main conference video
video
recvonly
sidebar audio
audio
sendrecv
sidebar video
video
sendrecv
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4. sidebarByValResponse/update message (sidebar's
updates accepted)
xcon-userid:Alice@example.com
xcon:8974545@example.com
update
200
success
2
5. userRequest/update message (Bob updates his media)
xcon-userid:Bob@example.com
xcon:8974545@example.com
update
main conference audio
123
inactive
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6. userResponse/update message (Bob's preferences are set)
xcon-userid:Bob@example.com
xcon:8974545@example.com
update
200
success
3
Figure 20: Internal Sidebar Messaging Details
7.2. External Sidebar
Figure 21 provides an example of a different approach towards
sidebars. In this scenario, one client, Alice, is involved in an
active conference with Bob, Carol, David, and Ethel. Alice gets an
important text message via a whisper from Bob that a critical
customer needs to talk to Alice, Bob, and Ethel. Alice creates a
sidebar to have a side discussion with the customer Fred including
the participants in the current conference with the exception of
Carol and David, who remain in the active conference. The difference
from the previous scenario is that Fred is not part of the parent
conference: this means that different policies might be involved,
considering that Fred may access information coming from the parent
conference, in case the sidebar was configured accordingly. For this
reason, in this scenario, we assume that Alice disables all the media
from the original (parent) conference within the sidebar. This means
that, while in the previous example Alice and Bob still heard the
audio from the main conference in background, this time no background
is made available. Alice initiates the sidebar by sending a request
to the conference server to create a conference reservation based
upon the active conference object. Alice, Bob and Ethel would remain
on the roster of the main conference in a hold state. Whether or not
the hold state of these participants is visible to other participants
depends upon the individual and local policy. However, providing the
hold state allows the participants in the main conference to see that
others in the conference are busy. Note, that a separate conference
could have been created by Alice to allow Bob and Ethel to talk to
Fred. However, creating a sidebar has somewhat of an advantage by
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allowing the conference to be created using some of the same settings
(e.g., role, floor control, etc.) that Bob and Ethel had in the main
conference and it would allow for updates such that the media could
be updated, for example, to provide audio from the main conference.
Alice Bob ConfS
| | |
|(1) sidebarByRefRequest(confUserID, |
| confObjID, create) |
|--------------------------------------------->|
| | |
| | (a) Create +---|
| | sidebar-by-ref | |
| | (new conf obj | |
| | cloned from +-->|
| | confObjID) | Sidebar now has
| | | id confObjID*
|(2) sidebarByRefResponse(confUserID, | (parent mapping
| confObjID*,create,200,success, | conf<->sidebar)
| version,sidebarByRefInfo) |
|<---------------------------------------------|
| | |
|(3) sidebarByRefRequest(confUserID, |
| confObjID*,update,sidebarByRefInfo) |
|--------------------------------------------->|
| | |
| | (b) Create +---|
| | new user for | |
| | Fred | |
| | +-->|
| | |
| | (c) Update +---|
| | sidebar-by-ref | |
| | (media, users | |
| | policy, etc.) +-->|
| | | Sidebar is modified:
| | | media from the
| | | parent conference is
| | | not available to
|(4) sidebarByRefResponse(confUserID, | anyone
| confObjID*, update, |
| 200, success, version) |
|<---------------------------------------------|
| | |
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| | Notify (Fred |
| | added to |
| | sidebar users) |
| |<----------------------|
| | |
' ' '
' ' '
' ' '
Figure 21: Client Creation of an External Sidebar
1. Upon receipt of the sidebarByRefRequest message to create a new
sidebar conference, based upon the active conference specified by
in the request, the conference server uses that
active conference to clone a conference reservation for the
sidebar. The sidebar reservation is NOT independent of the
active conference (i.e., parent). The conference server, as
before, allocates a new XCON-URI ("confObjID*" in Figure 21) to
be used for any subsequent protocol requests toward the sidebar
reservation. The mapping between the sidebar XCON-URI and the
one associated with the main conference is maintained by the
conference server and it is gathered from the
element in the sidebar conference object.
2. Upon receipt of the sidebarByRefResponse message, which
acknowledges the successful creation of the sidebar object, Alice
decides that only Bob and Ethel, along with the new participant
Fred are to be involved in the sidebar. Thus, she manipulates
the membership accordingly. Alice also sets the media in the
such that the participants in the sidebar don't
receive any media from the main conference. All these settings
are provided to the conferencing server by means of a new
sidebarByRefRequest message, with an "update" .
3. Alice sends the aforementioned sidebarByRefRequest message to
update the information in the reservation and to create an active
conference. Upon receipt of the sidebarByRefRequest/update
message, the conference server ensures that Alice has the
appropriate authority based on the policies associated with that
specific conference object to perform the operation. The
conference server also validates the updated information in the
reservation. Since Fred is a new user for this conferencing
system, a conference user identifier (XCON-USERID) is created for
Fred. Specifically, Fred is added to the conference by only
providing his SIP URI. Based upon the contact information
provided for Fred by Alice, the call signaling to add Fred to the
conference may be instigated through the focus (e.g., if Fred had
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a "dial-out" value for the 'method' attribute in his
field under ) at the actual activation of the
sidebar.
4. The conference server sends a sidebarByRefResponse message and,
depending upon the policies, the initiator of the request (i.e.,
Alice) and the participants in the sidebar (i.e., Bob and Ethel)
may be notified of his addition to the sidebar via the conference
notification service.
1. sidebarByRefRequest/create message (Alice creates an
external sidebar)
xcon-userid:Alice@example.com
xcon:8977878@example.com
create
2. sidebarByRefResponse/create message (created
sidebar returned)
xcon-userid:Alice@example.com
xcon:8971212@example.com
create
200
success
1
SIDEBAR CONFERENCE registered by Alice
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main conference audio
audio
sendrecv
main conference video
video
sendrecv
false
xcon:8977878@example.com
3. sidebarByRefRequest/update message (Alice updates the sidebar)
xcon-userid:Alice@example.com
xcon:8971212@example.com
update
sidebar with Alice, Bob, Ethel and Fred
main conference audio
audio
inactive
main conference video
video
inactive
sidebar audio
audio
sendrecv
sidebar video
video
sendrecv
single-view
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false
4. sidebarByRefResponse/update message (sidebar updated)
xcon-userid:Alice@example.com
xcon:8971212@example.com
update
200
success
2
Figure 22: External Sidebar Messaging Details
7.3. Private Messages
The case of private messages can be handled as a sidebar with just
two participants, similar to the example in Section 7.1. Unlike the
previous example, rather than using audio within the sidebar, Alice
could just add an additional text-based media stream to the sidebar
in order to convey her textual messages to Bob, while still viewing
and listening to the main conference.
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In this scenario, Alice requests to the conference server the
creation of a private chat room within the main conference context
(presented in Figure 19) in which the involved participants are just
Bob and herself. This can be achieved through the following CCMP
transaction (Figure 23).
1. Alice forwards a sidebarByValRequest/create message to the
conference server with the main conference XCON-URI in the
parameter and the desired sidebar conference object
in the field. In this way, a sidebar creation
using user-provided conference information is requested from the
conference server. Please note that, unlike the previous sidebar
examples, in this case, a completely new conference object to
describe the sidebar is provided: there is no cloning involved,
while the still enforces the parent-child
relationship between the main conference and the to-be-created
sidebar.
2. The conference server, after checking Alice's rights and
validating the conference object carried in the request, creates
the required sidebar-by-val conference and a new XCON-URI for it.
Instead of cloning the main conference object, as shown in
Sections 7.1 and 7.2, the sidebar is created on the basis of the
user-provided conference information. However, the parent
relationship between the main conference and the newly created
sidebar is still maintained by the conference server (as a
consequence of the chosen CCMP request message type -- the
sidebarByVal one) and it is reflected by the
element in the element returned in the
sidebarByValResponse message. Please notice that, according to
the CCMP specification, the return of the created sidebar data in
this kind of "success" response is not mandatory.
1. sidebarByValRequest/create message (Alice creates a private
chat room between Bob and herself)
xcon-userid:Alice@example.com
xcon:8977878@example.com
create
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private textual sidebar alice - bob
main conference audio
audio
recvonly
main conference video
video
recvonly
sidebar text
text
sendrecv
2. sidebarByValResponse/create message (sidebar returned)
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xcon-userid:Alice@example.com
xcon:8974545@example.com
create
200
success
1
private textual sidebar alice - bob
main conference audio
audio
recvonly
main conference video
video
recvonly
sidebar text
text
sendrecv
xcon:8977878@example.com
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Figure 23: Sidebar for Private Messages Scenario
7.4. Observing and Coaching
"Observing and Coaching" is one of the most interesting sidebar-
related scenarios. In fact, it highlights two different interactions
that have to be properly coordinated.
An example of observing and coaching is shown in Figure 25. In this
example, call center agent Bob is involved in a conference with
customer Carol. Since Bob is a new agent and Alice sees that he has
been on the call with Carol for longer than normal, she decides to
observe the call and coach Bob as necessary. Of course, the
conferencing system must make sure that the customer Carol is not
aware of the presence of the coach Alice. This makes the use of a
sidebar necessary for the success of the scenario.
Consider the following as the conference document associated with the
video conference involving Bob (the call agent) and Carol (the
customer) (Figure 24):
CUSTOMER SERVICE conference
sip:8978383@example.com
conference sip uri
service audio
audio
sendrecv
Barnes, et al. Informational [Page 64]
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service video
video
sendrecv
single-view
true
Bob - call agent
123
sendrecv
456
sendrecv
Carol - customer
123
sendrecv
456
sendrecv
Figure 24: A Call-Center Conference Object Example
Barnes, et al. Informational [Page 65]
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Alice Bob ConfS
| | |
|(1) sidebarByRefRequest(confUserID, |
| confObjID, create) |
|--------------------------------------------->|
| | |
| | (a) Create +---|
| | sidebar-by-ref | |
| | (new conf obj | |
| | cloned from +-->|
| | confObjID) | Sidebar now has
| | | id confObjID*
|(2) sidebarByRefResponse(confUserID, | (parent mapping
| confObjID*,create,200,success, | conf<->sidebar)
| version,sidebarByRefInfo) |
|<---------------------------------------------|
| | |
|(3) sidebarByRefRequest(confUserID, |
| confObjID*,update,sidebarByRefInfo) |
|--------------------------------------------->|
| | |
| | (b) Update +---|
| | sidebar-by-val | |
| | (media, users | |
| | policy, etc.) +-->|
| | | Sidebar is modified:
| | | unilateral sidebar
| | | audio, Carol excluded
| | | from the sidebar
|(4) sidebarByRefResponse(confUserID, |
| confObjID*, update, |
| 200, success, version) |
|<---------------------------------------------|
| | |
| | Notify (Bob |
| | he's been added to |
| | sidebar users) |
| |<----------------------|
| | |
' ' '
' ' '
' ' '
Figure 25: Supervisor Creating a Sidebar for Observing/Coaching
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RFC 6504 CCMP Call Flow Examples March 2012
1. Upon receipt of the sidbarByRefRequest/create message from Alice
to create a new sidebar conference from the received
in the request, the conference server uses the received active
conference to clone a conference reservation for the sidebar.
The conference server also allocates a new XCON-URI to be used
for any subsequent protocol requests directed to the new sidebar.
The conference server maintains the mapping between this sidebar
conference ID and the one associated with the main conference
instance. The conference server sends a sidebarByRefResponse
message with the new XCON-URI in the field and other
relevant information in the .
2. Upon receipt of the sidebarByRefResponse message, Alice
manipulates the data received in the in the
response. Alice wants only Bob to be involved in the sidebar;
thus, she updates the to include only Bob
and herself. Alice also wants the audio to be received by
herself and Bob from the original conference, but wants any
outgoing audio from herself to be restricted to the participants
in the sidebar, whereas Bob's outgoing audio should go to the
main conference, so that both Alice and the customer Carol hear
the same audio from Bob. Alice sends a sidebarByRefRequest
message with an "update" including the updated
sidebar information in the element.
3. Upon receipt of the sidebarByRefRequest/update message, the
conference server ensures that Alice has the appropriate
authority based on the policies associated with that specific
conference object to perform the operation. In order to request
the insertion of a further media stream in the sidebar (i.e., in
this example an audio stream from Alice to Bob), the requester
has to provide a new element in the
field of the . The mandatory 'label' attribute
of that new is filled with a dummy value
"AUTO_GENERATE_1", but it will contain the real server-generated
media stream identifier when the media stream is effectively
allocated on the server side. Similarly, the mandatory 'id'
attribute in the element referring to the new sidebar
audio stream under both Alice's and Bob's contains a
wildcard value, respectively, "AUTO_GENERATE_2" and
"AUTO_GENERATE_3": those values will be replaced with the
appropriated server-generated identifiers upon the creation of
the referred media stream. We are assuming the conference server
is able to recognize those dummy values as placeholders.
4. After validating the data, the conference server sends a
sidebarByRefResponse message. Based upon the contact information
provided for Bob by Alice, the call signaling to add Bob to the
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sidebar with the appropriate media characteristics is instigated
through the focus. Bob is notified of his addition to the
sidebar via the conference notification service; thus, he is
aware that Alice, the supervisor, is available for coaching him
through this call.
1. sidebarByRefRequest/create message (Alice as coach creates a sidebar)
xcon-userid:alice@example.com
xcon:8978383@example.com
create
2. sidebarByRefResponse/create message (sidebar created)
xcon-userid:alice@example.com
xcon:8971313@example.com
create
200
Success
1
SIDEBAR CONFERENCE registered by alice
main conference audio
audio
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sendrecv
main conference video
video
sendrecv
xcon:8971313@example.com
false
3. sidebarByRefRequest/update message (Alice introduces unilateral
sidebar audio and excludes Carol from the sidebar)
xcon-userid:alice@example.com
xcon:8971313@example.com
update
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Coaching sidebar Alice and Bob
Alice-to-Bob audio
audio
sendrecv
false
AUTO_GENERATE_1
sendonly
AUTO_GENERATE_1
recvonly
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4. sidebarByRefRequest/update message (updates accepted)
xcon-userid:alice@example.com
xcon:8971313@example.com
update
200
success
2
Figure 26: Coaching and Observing Messaging Details
8. Removing Participants and Deleting Conferences
The following scenarios detail the basic operations associated with
removing participants from conferences and entirely deleting
conferences. The examples assume that a conference has already been
correctly established, with media, if applicable, per one of the
examples in Section 5.
8.1. Removing a Party
Figure 27 provides an example of a client, Alice, removing another
participant, Bob, from a conference. This example assumes an
established conference with Alice, Bob, Claire, and Duck. In this
example, Alice wants to remove Bob from the conference so that the
group can continue in the same conference without Bob's
participation.
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Alice Bob Claire ConfS
| | | |
|(1) userRequest(confUserID,| |
| confObjID, delete,| |
| userInfo) | |
|-------------------------------------->|
| | | |
| | | (a) Focus |
| | | tears down|
| | | signaling |
| | | to Bob |
| |<----------------------|
| | |
| | (b)Deletes+---|
| | | Bob | |
| | | as a | |
| | | user +-->|
| | | in |
| | | confObj |
| | | |
|(2) userResponse(confUserID,confObjID, |
| delete,200,success,version) |
|<--------------------------------------|
| | | |
| | | |
| | | (c) Notify|
| | | ("Bob just|
| | | left") |
| | |<----------|
| | | |
' ' ' '
' ' ' '
' ' ' '
Figure 27: Client Manipulation of Conference - Remove a Party
1. Alice sends a userRequest message with a "delete" .
The conference server ensures that Alice has the appropriate
authority based on the policies associated with that specific
conference object to perform the operation.
2. Based upon the contact and media information in the conference
object for Bob in the element, the conferencing system
starts the process to remove Bob (e.g., the call signaling to
remove Bob from the conference is instigated through the focus).
The conference server updates the data in the conference object,
thus, removing Bob from the list. After updating the
data, the conference server sends a userResponse message to
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Alice. Depending upon the policies, other participants (e.g.,
Claire) may be notified of the removal of Bob from the conference
via the conference notification service.
1. userRequest/delete message (Alice deletes Bob)
xcon-userid:Alice@example.com
xcon:8977794@example.com
delete
2. userResponse/delete message (Bob has been deleted)
xcon-userid:Alice@example.com
xcon:8977794@example.com
delete
200
success
17
Figure 28: Removing a Participant Messaging Details
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8.2. Deleting a Conference
In this section, an example of a successful conference deletion is
provided (Figure 29).
Alice ConfS
| |
|(1)confRequest(confUserID, |
| confObjID, delete) |
|------------------------------>|
| (a)Delete +---|
| Conf | |
| Object | |
| +-->|
| |--+ (b) MS
| | | removes related
| | | mixer instances and
| |<-+ their participants
| | (SIP signaling as well)
| |
|(2)confResponse(confUserID, |
| confObjID,delete,200, |
| success) |
| |
|<------------------------------|
| |
' '
Figure 29: Deleting a Conference
1. The conferencing system client Alice sends a confRequest message
with a "delete" operation to be performed on the conference
identified by the XCON-URI carried in the parameter.
The conference server, on the basis of the included
in the receipt request, ensures that Alice has the appropriate
authority to fulfill the operation.
2. After validating Alice's rights, the conference server instigates
the process to delete the conference object, disconnecting
participants and removing associated resources such as mixer
instances. Then, the conference server returns a confResponse
message to Alice with "200" as and the deleted
conference XCON-URI in the field.
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1. confRequest/delete message (Alice deletes a conference)
xcon-userid:Alice@example.com
xcon:8977794@example.com
delete
2. confResponse/delete message ("200", "success")
xcon-userid:Alice@example.com
xcon:8977794@example.com
delete
200
success
Figure 30: Deleting a Conference Messaging Details
9. Security Considerations
The security considerations applicable to the implementation of these
call flows are documented in the XCON framework, with additional
security considerations documented in the CCMP document. Statements
with regard to the necessary security are discussed in particular
flows; however, this is for informational purposes only. The
implementer is encouraged to carefully consider the security
requirements in the normative documents.
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10. Acknowledgements
The detailed content for this document is derived from the prototype
work of Lorenzo Miniero, Simon Pietro Romano, Tobia Castaldi, and
their colleagues at the University of Napoli.
11. References
11.1. Normative References
[RFC5239] Barnes, M., Boulton, C., and O. Levin, "A Framework for
Centralized Conferencing", RFC 5239, June 2008.
[RFC6501] Novo, O., Camarillo, G., Morgan, D., and J. Urpalainen,
"Conference Information Data Model for Centralized
Conferencing (XCON)", RFC 6501, March 2012.
[RFC6502] Camarillo, G., Srinivasan, S., Even, R., and J.
Urpalainen, "Conference Event Package Data Format
Extension for Centralized Conferencing (XCON)", RFC 6502,
March 2012.
[RFC6503] Barnes, M., Boulton, C., Romano, S., and H. Schulzrinne,
"Centralized Conferencing Manipulation Protocol",
RFC 6503, March 2012.
[W3C.REC-xml-20081126]
Bray, T., Paoli, J., Sperberg-McQueen, C., Maler, E., and
F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth
Edition)", World Wide Web Consortium Recommendation REC-
xml-20081126, November 2008,
.
11.2. Informative References
[CALL-FLOWS]
Amirante, A., Castaldi, T., Miniero, L., and S. Romano,
"Media Control Channel Framework (CFW) Call Flow
Examples", Work in Progress, July 2011.
[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.
[RFC4575] Rosenberg, J., Schulzrinne, H., and O. Levin, "A Session
Initiation Protocol (SIP) Event Package for Conference
State", RFC 4575, August 2006.
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[RFC4579] Johnston, A. and O. Levin, "Session Initiation Protocol
(SIP) Call Control - Conferencing for User Agents",
BCP 119, RFC 4579, August 2006.
[RFC4582] Camarillo, G., Ott, J., and K. Drage, "The Binary Floor
Control Protocol (BFCP)", RFC 4582, November 2006.
[RFC4597] Even, R. and N. Ismail, "Conferencing Scenarios",
RFC 4597, August 2006.
[RFC5567] Melanchuk, T., "An Architectural Framework for Media
Server Control", RFC 5567, June 2009.
[RFC6505] McGlashan, S., Melanchuk, T., and C. Boulton, "A Mixer
Control Package for the Media Control Channel Framework",
RFC 6505, March 2012.
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Authors' Addresses
Mary Barnes
Polycom
TX
USA
EMail: mary.ietf.barnes@gmail.com
Lorenzo Miniero
Meetecho
Via Carlo Poerio 89/a
Napoli 80121
Italy
EMail: lorenzo@meetecho.com
Roberta Presta
University of Napoli
Via Claudio 21
Napoli 80125
Italy
EMail: roberta.presta@unina.it
Simon Pietro Romano
University of Napoli
Via Claudio 21
Napoli 80125
Italy
EMail: spromano@unina.it
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RFC, FYI, BCP