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

Paul Long Plong at SMITHMICRO.COM
Wed Jun 7 02:36:36 EDT 2000


Bob (Jane?),

H.323 allows the message that carries the accepted FC channels, e.g.,
Alerting, to also carry tunneled H.245 messages. What you may be thinking of
is that 8.2.1/H.323v3 (see below) says that an EP cannot tunnel H.245
_prior_ to the call-signaling message that carries the accepted FC channels.
It's okay to do it in the same message, though.

"The sending of encapsulated H.245 messages or the initiation of the
separate H.245 connection by either endpoint prior to the sending of a Q.931
message containing fastStart by the called endpoint terminates the Fast
Connect procedures."

Paul Long
Smith Micro Software, Inc.
"Primum non nocere"


-----Original Message-----
From: Jane Hua [mailto:huajane at YAHOO.COM]
Sent: Wednesday, June 07, 2000 12:51 AM
To: ITU-SG16 at MAILBAG.INTEL.COM
Subject: Re: On TD26 - Fast TCS and M/S negotiation in H.323v4


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
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

> 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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