Req clarification of H.245 SessionID

[Pete Cordell]

Dear All,

Please could some one clarify the use of the H.245 sessionID in
communicationModeCommand and OLC.

For example, H.245 says: "The sessionID is a unique RTP or T.120 Session
Identifier in the conference. It is used by the transmitter to refer to
the session to which the logical channel applies. <BOLD>Only the master
can create the session identification.</BOLD> "

Q: does this mean that the master defines the sessionID in a
communications mode command message, or in the OLC procedure.  e.g. is
it:

My endpoint(slave)           Remote endpoint(master)
---------> OLC (no SessID) ------------->
<--------- OLC ACK (SessID=1) -----------

OR:

My endpoint(slave)           Remote endpoint(master)
<-----ComModeComm (SessID 1 = xyz)<------
----------> OLC (SessID 1) ------------->
<--------OLC ACK (no SessID) <-----------

If it is the second case, what happens if the remote endpoint becomes
the master, but is not an MC.  Do you do:

My endpoint(slave)           Remote endpoint(master)
---------> OLC (no SessID) ------------->
<--------- OLC ACK (SessID=1) -----------

OR:

My endpoint(slave)           Remote endpoint(master)
----------> OLC (SessID 1) ------------->
<--------OLC ACK (no SessID) <-----------

If you want to open a second audio session with an associated second
video session in a point-to-point non-MC case, do you do:

My endpoint(slave)           Remote endpoint(master)
----------> OLC (SessID=0) ------------->
<--------OLC ACK (SessID=4) <------------
----> OLC (SessID=0, AssocSessID=4) ---->
<--------OLC ACK (SessID=5) <------------

OR is there a way to open the two channels at the same time?

Thanks for any pointers,

Pete

P.S. I'm sure Mark Reid wrote down some examples on these sorts of
things, but I can't seem to find them.
=================================
Pete Cordell
BT Labs
E-Mail: pete.cordell at bt-sys.bt.co.uk
Tel: +44 1473 646436
Fax: +44 1473 645499
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