I don't believe there was any APC. I introduced some ideas and proposed text on the mailing list. The text was revised in response to ensuing discussion and Jim inserted it into the IG draft. I agree it seems contradictory. The way it was written had changed "shall be the first message sent" to "should be the first message sent". The intention was that you wouldn't have to send TCS, but if the peer got totally confused about what was going on without it, the exchange would take place.

I believe that the Monterey meeting rejected my "shall" to "should" change but accepted everything else. I unfortunately wasn't present while this item was discussed. However, notice that in the last sentence of the paragraph, the EP "shall" respond to the TCS, and only "should" complete a caps exchange before doing anything else. So the EP can still do things essentially in parallel.

As an aside, my belief is that other H.245 procedures besides MSD may be initiated prior to completion of caps exchange, for example, OLC.

Regards,

Dave Walker Mitel Corporation Ontario, CANADA

Chris Purvis wrote:

Paul,

No. I think it comes out of things Dave was talking about. Do you recall, Dave?

By the way, you guys may as well be the first to know (I'll email the lists at some point): I'll moving on from Madge in two and a half weeks time, and although I'll still be in the telecoms industry I don't expect to be active in the H.323 arena, at least for a while.

Chris

...

-----Original Message----- From: Paul E. Jones [mailto:paul.jones@ties.itu.int] Sent: 23 June 1999 2:03 To: Chris.Purvis@MADGE.COM; pete@TECH-KNOW-WARE.COM Subject: Re: Re: Question about text in implementers guide

Chris,

Do you recall what APC introduced the text?

Paul

----- Original Message ----- From: Chris Purvis Chris.Purvis@MADGE.COM To: ITU-SG16@MAILBAG.INTEL.COM Sent: Wednesday, June 23, 1999 7:00 AM Subject: Re: Question about text in implementers guide

...

Pete,

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).

Regards, Chris

...

-----Original Message----- From: Pete Cordell [mailto:pete@TECH-KNOW-WARE.COM] Sent: 22 June 1999 9:54 To: ITU-SG16@MAILBAG.INTEL.COM 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 6.2.8.1, 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@tech-know-ware.com =============================================