Subject: Re: MGC-MG Control Relationship

From: "Neogi, Raja" <[email-masked]>
Date: Thu, 21 Oct 1999 10:38:15 -0700

Right from the beginning there was understanding
that multiple MGCs may control an MG but not at
the same time. There is only one primary MGC and
multiple secondary MGCs. Look at the Fault management
section of the latest draft.

This enables "fault tolerance".

raja neogi
Intel

-----Original Message-----
From: Hong Liu [mailto:[email-masked]]
Sent: Wednesday, October 20, 1999 10:01 PM
To: [email-masked]
Subject: MGC-MG Control Relationship

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

---

From: Danny Levin <[email-masked]>
Date: Thu, 21 Oct 1999 18:08:14 -0400

See MEGACO requirement :

8.1.  MG-MGC Association Requirements

The Protocol must:

a.   Support the establishment of a control relationship between an MGC
     and an MG.

b.   Allow multiple MGCs to send control messages to an MG. Thus, the
     protocol must allow control messages from multiple signalling
     addresses to a single MG.

Fault tolerance is not the only issue.
What about sharing resources : one announcement player that serves multiple
announcement controllers.

Danny

-----Original Message-----
From:   Media Gateway Control (megaco)
[mailto:[email-masked]] On Behalf Of Neogi, Raja
Sent:   Thursday, October 21, 1999 1:38 PM
To:     [email-masked]
Subject:        Re: MGC-MG Control Relationship

raja neogi
Intel

-----Original Message-----
From: Hong Liu [mailto:[email-masked]]
Sent: Wednesday, October 20, 1999 10:01 PM
To: [email-masked]
Subject: MGC-MG Control Relationship

Hi, all,

--Hong

---

From: Hong Liu <[email-masked]>
Date: Fri, 22 Oct 1999 10:16:26 -0400

Raja,

If this is what we mean by multiple MGCs controlling a single MG, I have no
problem with that at all. However, when I raised the question on the list, I
was under the impression that multiple MGCs are ACTIVELY controlling one MG
simultaneously. In other words, they are of equal roles in terms of control.
This raises questions as how share resources are managed, such as deadlock.

--Hong

---

From: Hong Liu <[email-masked]>
Date: Fri, 22 Oct 1999 10:24:47 -0400

Danny,

I am not against this feature totally. This is a priority issue: do we want to
allow this in version 1 or not. In my opinion, this issue requires more study.
From the email responses I saw so far, different people have different
interpretation on what it means. If my email starts a thread that helps clarify
the issue, then it serves the purpose.

Announcement server is a very special case of the MGs this protocol is used to
control. It is primarily a "read-only" server, hence resource contention is
less likely, but not completely. Shall we be more specific in the document on
how this feature is to be used?

--Hong