Internet DRAFT - draft-boulton-xcon-conference-control-package
draft-boulton-xcon-conference-control-package
XCON Working Group C. Boulton
Internet-Draft NS-Technologies
Intended status: Standards Track M. Barnes
Expires: January 17, 2013 Polycom
July 16, 2012
An XCON Client Conference Control Package for the Media Control Channel
Framework
draft-boulton-xcon-conference-control-package-07
Abstract
The Centralized Conferencing framework defines a model whereby client
initiated interactions are required for creation, deletion,
manipulation and querying the state of a of conference. This
document defines a Media Control Channel Package for XCON client
initiated Conference Control. The Package is based on the Media
Control Channel Framework, which is also used for media server
control, thus optimizing the implementation for some entities
participating in an XCON system.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on January 17, 2013.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. Control Package Detail . . . . . . . . . . . . . . . . . . . . 6
5.1. Control Package Name . . . . . . . . . . . . . . . . . . . 6
5.2. Framework Message Usage . . . . . . . . . . . . . . . . . . 6
5.3. Common XML Support . . . . . . . . . . . . . . . . . . . . 6
5.4. Control Message Bodies . . . . . . . . . . . . . . . . . . 6
5.5. REPORT Message Bodies . . . . . . . . . . . . . . . . . . . 6
5.6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
6.1. Control Package Registration . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
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1. Introduction
The Conference Control Manipulation Protocol (CCMP) [RFC6503]
provides a standards based mechanism to enable third party conference
clients participating to interoperate with conference servers and
manipulate conference parameters using HTTP as a transport. A Data
Model [RFC6501] provides the data associated with a conference
instance that is the target for the CCMP protocol operations.
A Control Channel Framework[RFC6230] has been created based on the
Session Initiation protocol (SIP). It uses SIP to setup, maintain
and terminate a reliable control channel for the purpose of
exchanging control based interactions. While the control of media
was the original problem domain for which this framework was
developed, the Control Framework provides an extension template for
creating extensions that specify the semantic detail associated with
the control channel operations. The extension documents are known as
Control Packages and an example is the 'Basic Mixer Control Package'
[RFC6505].
This document will specify a Control Package for Conference Control
using the SIP Control Framework. The target for these operations is
the same data, associated with conference instances per the data
model, as CCMP. It should be noted that this mechanism is a
complementary approach to CCMP. In fact this specification simply
provides a different transport mechanism. While the use of HTTP as a
transport for CCMP is ideal for certain network deployments (for
example Service Orientated Architectures), it is important to offer
an alternative access method for clients with non SOA based
technologies.
The Media Control Channel Framework provides the ideal mechanism for
reliably exchanging control messages between a conference client and
server. It provides inherent properties such as:
o Reliable delivery of control messages.
o Lightweight Protocol Data Units (PDU).
o Linked asynchronous transactional mechanism.
o Asynchronous event mechanism.
The SIP Control Framework uses SIP as its overlying rendezvous
mechanism. This provides all the inherent benefits like:
o SIP Service Location - Use SIP Proxies or Back-to-Back User Agents
for discovering Control Servers.
o SIP Security Mechanisms - Leverage established security mechanisms
such as Transport Layer Security (TLS) and Client Authentication.
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o Connection Maintenance - The ability to re-negotiate a connection,
ensure it is active, audit parameters, and so forth.
o Agnostic - Allows for ease of extension.
Not only is the Media Control Channel Framework an ideal mechanism
for controlling conference instances by participating clients, it
also provides the property of re-use by conferencing systems of
functionality implemented for controlling Media Servers etc. This
includes re-using the SIP stack for control channel setup as well as
the Control Channel Framework stack for receiving/sending the PDUs
for multiple control packages in a conference system.
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].
3. Terminology
This document reuses the terminology defined and used in the
framework and data model for centralized conferencing [RFC5239],
[RFC6501] and [RFC6503] .
4. Overview
The use of the Media Control Channel Framework offers an ideal
mechanism for creating, deleting and manipulating XCON conference
instances by participating clients. As the Control Channel Framework
is a generic mechanism, this section provides non-normative detail
showing how the Control Channel Framework can be applied to this
particular use-case. In [RFC5239], two distinct roles are defined -
A 'Control Client' and a 'Control Server'. Such roles are
interchangeable between entities within a session depending on
package requirements. A simple diagram is illustrated in Figure 1
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+--------------SIP Traffic--------------+
| |
v v
+-----+ +--+--+
| SIP | | SIP |
|Stack| |Stack|
+---+-----+---+ +---+-----+---+
| Control | | Control |
| Client |<----Control Channel---->| Server |
+-------------+ +-------------+
Figure 1: Basic Architecture
The XCON Conference Control package will cast a participating
compliant User Agent that wishes to control a conference instance as
a 'Control Client' as defined in the SIP Control Framework. It will
have permission to generate and issue commands in CONTROL messages as
defined in Section 5.2 of this document. It will also have the
ability to receive responses to Conference Package CONTROL requests
that are contained in either appropriate responses or subsequent
REPORT messages, also specified in Section 5.2. The specific format
of the conference control messages and responses are defined in
Section 5.4 and Section 5.5. They re-use the format specified in
CCMP[RFC6503]. This provides a common binding set with alternative
access mechanism depending on client requirements. The previous
diagram can be updated as illustrated in Figure 2.
+--------------SIP Traffic--------------+
| |
v v
+-----+ +--+--+
| SIP | | SIP |
|Stack| |Stack|
+---+-----+---+ +---+-----+---+
| XCON | | XCON |
| Control | | Conference |
| Client |<----Control Channel---->| System |
+-------------+ +-------------+
Figure 2: Conference Control Architecture
Editor's Note: The Overview section will be expanded in later
versions of the document.
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5. Control Package Detail
The Media Control Channel Framework defines rules that Control
Package extensions must provide mandatory information as described in
section 10 of [RFC6230]. This section fulfils the obligation.
5.1. Control Package Name
The SIP Control Framework requires a Control Package definition to
specify and register a unique package name. The name and version of
this Control Package is "xcon-conf-control/1.0".
5.2. Framework Message Usage
The Conference Control package uses the XML schema defined in CCMP
[RFC6503]. To maintain the consistency with the design of the XML
schema, the SIP Control Framework messages will be applied in a
similar manner. The CONTROL message will be used to contain requests
that enable conference manipulation - as specified in Section 5.4 and
can only travel from the client to a Conferencing System. Responses,
as specified in Section 5.5, can only travel from the Conferencing
System to an expectant client. Depending on the time it takes to
process the request (as specified in [RFC6230]), responses can either
be contained in a Control Framework 200 response or subsequent REPORT
method.
5.3. Common XML Support
The Control Framework requires a Control Package definition to
specify if the attributes for media dialog or conference references
are required.
This package requires that the XML Schema in Section 16.1 of
[RFC6230] MUST NOT be supported for media dialogs and conferences.
But rather this package SHOULD use the XML schema as defined in
[RFC6501], which is the same schema upon which CCMP is based.
5.4. Control Message Bodies
A valid CONTROL body message MUST conform to the XML schema defined
in [RFC6503] for the conference control. To be precise, the CONTROL
message body MUST comply only to the 'ccmp-request-type' complexType.
5.5. REPORT Message Bodies
A valid CONTROL body message MUST conform to the XML schema defined
in [RFC6503]. To be precise, the REPORT message body MUST comply
only to the 'ccmp-response-type' complexType.
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5.6. Examples
TODO
6. IANA Considerations
6.1. Control Package Registration
This section registers a new Media Control Channel Framework package,
per the instructions in Section 12.1 of [RFC6230].
To: ietf-sip-control@iana.org Subject: Registration of new Media
Control Channel Framework package Package Name: xcon-conf-control/1.0
[NOTE TO IANA/RFC-EDITOR: Please replace XXXX with the RFC number for
this specification.] Published Specification(s): RFCXXXX Person &
email address to contact for further information: IETF, XCON working
group, (xcon@ietf.org), Mary Barnes (mary.ietf.barnes@gmail.com).
7. Security Considerations
Access to conference control functionality needs to be tightly
controlled to avoid attackers disrupting conferences, adding
themselves to conferences or engaging in theft of services.
The Framework for Centralized Conferencing [RFC5239] specifies that
the protocols used for manipulation and retrieval of confidential
information MUST support a confidentiality and integrity mechanism.
To support the confidentiality and integrity requirements, all
conference control information included in the package defined in
this document SHOULD be carried over TLS.
Additional information should be added to this section based on the
final material in the Control Framework for SIP [RFC6230].
There are also security issues associated with the authorization to
perform actions on the conferencing system to invoke specific
capabilities. Implementers MUST deploy appropriate authentication
and authorization mechanisms to ensure that only authorized entities
are able to manipulate the data.
8. Acknowledgments
9. References
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9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC6501] Novo, O., Camarillo, G., Morgan, D., and J. Urpalainen,
"Conference Information Data Model for Centralized
Conferencing (XCON)", RFC 6501, March 2012.
[RFC6230] Boulton, C., Melanchuk, T., and S. McGlashan, "Media
Control Channel Framework", RFC 6230, May 2011.
[RFC6505] McGlashan, S., Melanchuk, T., and C. Boulton, "A Mixer
Control Package for the Media Control Channel Framework",
RFC 6505, March 2012.
[RFC6503] Barnes, M., Boulton, C., Romano, S., and H. Schulzrinne,
"Centralized Conferencing Manipulation Protocol",
RFC 6503, March 2012.
9.2. Informative References
[W3C.CR-wsdl20-20051215]
Chinnici, R., Moreau, J., Ryman, A., and S. Weerawarana,
"Web Services Description Language (WSDL) Version 2.0 Part
1: Core Language", W3C CR CR-wsdl20-20051215,
December 2005.
[W3C.REC-soap12-part1-20030624]
Gudgin, M., Mendelsohn, N., Nielsen, H., Moreau, J., 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., Nielsen, H., Gudgin, M., and
J. Moreau, "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>.
[RFC5239] Barnes, M., Boulton, C., and O. Levin, "A Framework for
Centralized Conferencing", RFC 5239, June 2008.
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Authors' Addresses
Chris Boulton
NS-Technologies
Email: chris@ns-technologies.com
Mary Barnes
Polycom
TX
Email: mary.ietf.barnes@gmail.com
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