Question about text in implementers guide

Chris Purvis Chris.Purvis at MADGE.COM
Wed Jun 23 07:00:46 EDT 1999


The background is that there should be no good reason for not tunnelling TCS
and MSDet into the same H.225 message.  I agree that the wording ought to be
improved (I heard or suggested at Monterey two or three alternatives that I
consider better than the one you quote).


> -----Original Message-----
> From: Pete Cordell [mailto:pete at TECH-KNOW-WARE.COM]
> Sent: 22 June 1999 9:54
> Subject: Question about text in implementers guide
> Dear All,
> The following revised paragraph seems to have been added to
> H.323 v3 via the
> implementers guide.
> Endpoint system capabilities are exchanged by transmission of
> the H.245
> terminalCapabilitySet message. This capability message shall
> be the first
> H.245 message sent. If prior to successful completion of
> terminal capability
> exchange, any other procedure fails, (i.e. rejected, not
> understood, not
> supported) then the initiating endpoint should initiate and
> successfully
> complete terminal capability exchange before attempting any
> other procedure.
> An endpoint which receives a terminalCapabilitySet message
> from a peer prior
> to initiating capabilities exchange shall  respond as
> required by,
> and should initiate and successfully complete capabilities
> exchange with
> that peer prior to initiating any other procedure.
> I'm a bit confused about what it is saying.  It seems to be
> saying that an
> endpoint can send a TCS and prior to receiving the Ack, send
> MSD (as there
> is really no other procedure that can fail).  This is a good thing.
> However, it then says, that if for some reason you receive
> TCS before you
> yourself have sent one, then, I think the paragraph is saying
> that, you must
> send your own TCS, and are not allowed to do MSD until you
> get the TCS Ack
> back.  This is a bad thing.  But worse still there seems to
> be conflicting
> information for what is essentially a minor timing issue.
> Could someone
> kindly explain to me what the background to it is.
> Thanks,
> Pete
> =============================================
> Pete Cordell
> pete at
> =============================================

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