AW: On TD26 - Fast TCS and M/S negotiation in H.323v4

Klaghofer Karl ICN SIB NL D1 Karl.Klaghofer at ICN.SIEMENS.DE
Wed Jun 7 12:49:07 EDT 2000


Osaka contributions like APC-1866 suggested to enhance the Fast Start
structures by adding elements like userInputCapability to the fast start
structure (to allow e.g. negotiation of the user input caps as early as
possible together with fast start for subsequent UserInputCapability
messages to be sent). This was rejected since the participants felt that
start adding pieces of H.245 to Fast Connect might turn out as a never
ending story.

Instead, the consensus in Osaka was to allow the complete H.245 tunnel
itself together with the fast start in SETUP. The backwards compatibility
issue is of course important to consider.

I agree with the principles what Paul said. I propose to continue the agreed
approach from Osaka and further develop it using a new tunnel field in
H323-UU-PDU construct (however, I believe it is saver that this new tunnel
field should be used not only in SETUP but also in the other H.225.0
messages).

Remark: I do not like the term "earlyH245Control" since "early H.245" in
H.323 means something total different, as mentioned alrealy by a previous
e-mail. Since this is in fact a new tunnel procedure available with v4, it
could be named something like "245V4Control. But this are only names....

Regards,
Karl


> -----Ursprüngliche Nachricht-----
> Von:  Paul E. Jones [SMTP:paulej at PACKETIZER.COM]
> Gesendet am:  Wednesday, June 07, 2000 09:59
> An:   ITU-SG16 at mailbag.cps.intel.com
> Betreff:      Re: On TD26 - Fast TCS and M/S negotiation in H.323v4
>
> Jane,
>
> I suspect that TD-26 has the procedural issues addressed-- it will just be
> a
> matter of specifying the usage of a different field.
>
> I'll have to review what is written there, but the most obvious way to
> prevent race conditions is to specify that channels may not be opened via
> H.245 until Fast Connect is accepted, explicitly refused, or implicitly
> refused by not receiving a fastStart element up to and including CONNECT.
>
> Paul
>
> ----- Original Message -----
> From: "Jane Hua" <huajane at YAHOO.COM>
> To: <ITU-SG16 at mailbag.cps.intel.com>
> Sent: Wednesday, June 07, 2000 2:18 AM
> Subject: Re: On TD26 - Fast TCS and M/S negotiation in H.323v4
>
>
> > Pre Script: Sorry for the previous mail
> >
> > Hi All,
> >
> > As far as my understanding goes, the purpose of prohibiting both
> > fastStart and H.245 tunnel in SETUP was to avoid race conditions in two
> > tunnels (fastStart can also be considered as a H.245 tunnel with
> > different procedures). Here we are adding a new tunnel which will lead
> > to more such race scenarios until proper care is taken in defining the
> > procedures.
> >
> > The decision on this should not be like a voice vote in Congress. The
> > procedures should be clearly documented and circulated over the
> > reflector and let people argue on those concrete documented steps.
> >
> > Let us see, can we fix the problem introduced by introduction of
> > fastStart?
> >
> > Regards,
> > Jane Hua
> >
> >
> > Paul-
> > The problem is that inclusion of an H.245 message in the tunnel
> > terminates
> > FastStart according to section 8.2.1 of H.323.  This could be
> > "satisfied"
> > by using the early H.245 element for the replys so that FastStart could
> > proceed.
> > At least this mechanism would make it easy to know that the responder
> > (the
> > called endpoint) was able to overlap FastStart and H.245.
> > -Bob
> > ----------------------------------------------------
> > Bob Gilman       rrg at lucent.com      +1 303 538 3868
> >
> >
> > Paul Long wrote:
> > >
> > > Bob,
> > >
> > > H.323 only says that fastStart and h245Control cannot both be included
> in
> > > _Setup_, so it could indeed be included in the Setup-UUIE type.
> > >
> > > Paul Long
> > > Smith Micro Software, Inc.
> > >
> > > -----Original Message-----
> > > From: Callaghan, Robert [mailto:Robert.Callaghan at ICN.SIEMENS.COM]
> > > Sent: Tuesday, June 06, 2000 10:27 AM
> > > To: ITU-SG16 at MAILBAG.INTEL.COM
> > > Subject: Re: On TD26 - Fast TCS and M/S negotiation in H.323v4
> > >
> > > Paul,
> > >
> > > It would be required in the SETUP, CALL PROCeeding, ALERT, FACILITY,
> and
> > > CONNECT message in that all of these messages can be sent before Fast
> > > Start
> > > is completed or may not be present with Fast Start elements based on
> v2.
> > >
> > > Bob
> > >
> > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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>
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