Subject: [Megaco] draft-ietf-megaco-callflows-00.txt

From: Raphael Tryster <[email-masked]>
Date: Thu, 18 Apr 2002 21:37:53 +0200

I have some questions about the examples in this document relating to call
transfer:

1.	When UserB presses flash and is dialing UserC, what happens with
UserA?  It appears to me that in steps 19 through 30, nothing happens that
affects UserA, so UserA and UserB would continue to hear each other.  Is
this a real world scenario?  If not, what would happen in the real world?

2.	In the description before step 24, I think that "The physical
termination TermA is added to context 1" should be "The physical termination
TermC is added to context 3".

3.	Step 31 seems to be missing the ephemeral termination EphB, referred
to in the description preceding it.

4.	After step 31, the remote SDP of UserB and UserC point to each
other, but the remote SDP of UserA still points to UserB.  What is the
physical effect of this?

	And about call waiting:

5.	I believe the description before step 26 should refer to TermC
instead of TermB, and MG3 instead of MG2.

6.	In this example, each of the physical terminations has a single
ephemeral termination in the same context, and the MGC sends updated remote
SDP information each time UserB presses flash.  What are the considerations
for doing it this way, rather than creating in UserB's context a separate
ephemeral termination for each of its conversation partners and switching
the mode, such that at any time one is sendrecv and the others are inactive?

7.	What happens to UserA while UserB is in conversation with UserC?
UserA's remote SDP information still points to UserB.

	And some general questions:

8.	Does it ever make sense, and is it possible, to send a signal
"backwards" to a user by directing it at an ephemeral termination to which
it is connected?  For example, when UserA and UserB have EphA and EphB
pointing to each other, is it possible for an MGC to send a signal to EphA
to be sent to UserB?

9.	Under what circumstances, is any, could there be more than one
physical termination in a context?

Raphael Tryster