Subject: MGC-MG Control Relationship

From: Hong Liu <[email-masked]>
Date: Thu, 21 Oct 1999 01:00:51 -0400

Hi, all,

I have been involved in MEGACO/H.248 from the very beginning. I have
been always under the impression that at least for version 1 of the
protocol, at any instance of time, a single MG (physical or virtual) is
under the control of EXACTLY ONE MGC. However, in the MEGACO/H.248
discussion this afternoon (10/20), I was told that this is not true. In
other words, multiple MGCs can control the same MG at the same time. I
may be totally out of touch, this is a big surprise to me. Maybe someone
on the list can remind me when this decision was made.

While there may be situations where multiple MGCs controlling a single
MG is desirable, there is a lot of issues to be resolved for sharing the
same set of terminations. This is certainly an area that requires
further study. I just don't think it is a good idea to include this
feature in the current protocol.

--Hong

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From: Christer Holmberg <[email-masked]>
Date: Thu, 21 Oct 1999 12:41:54 +0300

Hi,

For redundancy reasons you could have multiple MGCs controlling one MG (only
one at the time, though, if you use the active/stand-by architecture), and
you could devide one physical MG into multiple virtual MGs, each controlled
by a separate MGC. However, I think what you mean is that when multiple MGCs
can control the SAME termination/endpoint at the SAME time. This can happen
if you, for example, have some kind of load share between the MGCs, or if
different tasks are handled by different MGCs, or for some other reasons. No
matter the reason, I think there are scenarios when this is needed, and it
IS a problem, but it is "out of the scope of the H.248 protocol" (this is
said in the draft). Of course, you don't solve problems by giving them to
someone else, but this is more an inter-MGC communication problem, and also
a security issue, and must of course be solved - not only for the case when
a MG is controlled by multiple MGCs, but also for other purposes.

Christer