Subject: question about conference

From: "mu lj" <[email-masked]>
Date: Thu, 14 Jun 2001 17:06:42 +0800

Tom Taylor:

    There is a conference call, user1 and user2 in MG1,user3 in MG2, 
the conference resources in MG3.
1. How to describe a conference resource use terminationID?
2. How to choose a RTP resource in a conference resource?
3. What is Call flows about this conference call?

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From: "Even ,Roni" <[email-masked]>
Date: Sun, 17 Jun 2001 08:30:54 +0200

mu lj

In general a conference is implied by having all streams in a context mixed.
In you question since I assume you have two physical MGs There are two
options to model the conference
1. A cascaded conference which means you have mixed streams from MG1 to MG2.
In that case there is a context in MG1 with user1 and user2 and according to
H.248 mixing is implied (How is implementation dependent) and the output
stream goes to MG2 as a new RTP stream to a context with user3. These are
bi-directional connections. The context with version 2 of H.248 can have
properties based on package that will define the mixing.
2. MG1 is just passing user1 and user2 streams. You may create two contexts
one for each user in MG1 and have a context with three termination in MG2.

The MGs handle only media streams. Call signalling and control are in the
MGC. If one MGC is handling both MGs then it is a simple conference with the
streams according to the above options.
If you have two MGC each controlling an MG then it is a cascaded conference
according to H.323. 

Please note that the ITU is working on MCU decomposition and a profile and
packages for supporting multimedia conferences will be defined.

Roni
**********************************************
Roni Even
VP Product Planning
Polycom Israel
Tel: +972-3-9251200
Fax: +972-3-9211571
Email: [email-masked]