Distributed Multisite Circuit BasedConferencing

In the ITU standards work, a ``conference'' refers to a group of geographically dispersed nodes that are joined together and that are capable of exchanging audiographic and audiovisual information across various communication networks.

Participants taking part in a conference may have access to various types of media handling capabilities such as audio only (telephony), audio and data (audiographics), audio and video (audiovisual), and audio, video, and data (multimedia).

The F, H, and T Series Recommendations provide a framework for the interworking of audio, video, and graphics terminals on a point-to-point basis through existing, telecommunication networks. They also provide the capability for three or more terminals in the same conference to be interconnected by means of an MCU.

This Recommendation provides a high-level framework for conference management and control of audiographics and audiovisual terminals, and MCUS. It coexists with companion Recommendations T.122 and T.125 (MCS) and T.123 (AVPS) to provide a mechanism for conference establishment and control. T.GCC also provides access to certain MCS functions and primitives, including tokens for conference conductorship. T.GCC, T.122, T.123, and T.125 form the minimum set of Recommendations to develop a fully functional terminal or MCU.

Generic conference control (GCC) functional components: conference establishment and termination. maintenance, the conference roster, managing the application roster, remote actuation, conference conductorship, bandwidth control, and application registry services. The service definitions for the primitives associated with these functional components are contained later, as are the corresponding protocol definitions are

The figure below shows an example of how the GCC components fit together.

The Top GCC Server contains Application Registry information for the conference

Each Node participating in a GCC conference consists of an MCS layer, a GCC layer, a Node Controller and may also include one or more Client Applications. The relationship between these components within a single node is illustrated in the figure below.

  

Figure 7.3: ITU Based Generic Conference Control

The Node Controller is the controlling entity at a node, dealing with the aspects of a conference which apply to the entire node. The Node Controller interacts with GCC, but may not interact directly with MCS. Client Applications also interact with GCC, and may or may not interact with MCS directly. The services provided by GCC to Client Applications are primarily to enable peer Client Applications to communicate directly, via MCS. Communication between Client

Applications or between Client Applications and the Node Controller may take place, but is a local implementation matter not covered by this Recommendation. The practical distinction between these Node Controller and the Client Applications is also a local matter not covered by this Recommendation.

The Generic Conference Control Service includes the set of primitives as shown in table 7.1 .

 

Table 7.1: Conference Control Primitives

GCC-Conference-Join

GCC-Conference-Query

GCC-Conference-Create

GCC-Conference-Add

GCC-Conference-Invite

GCC-Conference-Lock

GCC-Conference-Unlock

GCC-Conference-Disconnect

GCC-Conference-Terminate

GCC-Conference-Eject-User

GCC-Conference-Transfer

GCC-Conference-Time-Remaining

GCC-Conference-Time-Inquire

GCC-Conference-Extend

GCC-Conference-Ping

The Conference Roster

GCC-conference-Announce-Presence

GCC-Conference-Roster-Inquire

The Application Roster

GCC-Application-Enrol

GCC-Application-Attach

GCC-Application-User-ID

GCC-Application-Roster-Report

GCC-Application-Roster-Inquire

Remote Actuation

GCC-Action-List-Announce

GCC-Action-List-Inquire

GCC-Action-Actuate

Conference Conductorship

GCC-Conductor-Assign

GCC-Conductor-Release

GCC-Conductor-Please

GCC-Conductor-Give

GCC-Conductor-Inquire