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@bt-sys.bt.co.uk Tel: +44 1473 646436 Fax: +44 1473 645499 =================================