Force remote to start H.245 session?

[Chris Wayman Purvis]

Paul,

> I think you see my point, then. Now that I think about it, an EP _is_
> required to at least send its TCS, if it has not already, if it receives an
> H.245 request message. Specifically, it cannot send the TCSAck until it has
> sent its own TCS, according to the following:
>
> 8.2/H.323v3: "Endpoint system capabilities are exchanged by transmission of
> the H.245 terminalCapabilitySet message. This capability message shall be
> the first H.245 message sent."

That's what I thought, although I didn't have the reference to hand...

> And then there's the following. I think it means that if an EP receives TCS
> without already having sent TCS itself, it shall do so now. Is that your
> understanding?
>
> 8.2/H.323v3: "An endpoint which receives a terminalCapabilitySet message
> from a peer prior to initiating capabilities exchange shall  respond as
> required by 6.2.8.1, and should initiate and successfully complete
> capabilities exchange with that peer prior to initiating any other
> procedure."

Let's just say that your interpretation is not so much my "understanding" of
that text as its "intention" when Dave Walker and I wrote that passage...

> So if an EP initiates H.245 procedures, the remote is forced to also perform
> H.245 procedures. Okay, that's what I was looking for. Maybe it just means
> that it has to perform the cap exchange. You know, both sides don't really
> need to initiate the MSD. It's enough that the side that first wanted to use
> H.245 procedures has performed it, so TCS alone is enough of a prelude to
> get the H.245 session up and running. Do you think this needs clarification
> text?

As long as MSD is completed that's fine.  I agree there's no point in it being
initiated by each side.  Is that required somewhere?  The intention was that
one should always do one's best to get MSD out of the way "as soon as
possible", but TCS must happen (or at least start...!) first.

Regards,
Chris
--
Dr Chris Purvis -- Development Manager
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