AW: On TD26 - Fast TCS and M/S negotiation in H.323v4
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@PACKETIZER.COM] Gesendet am: Wednesday, June 07, 2000 09:59 An: ITU-SG16@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@YAHOO.COM To: ITU-SG16@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@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@ICN.SIEMENS.COM] Sent: Tuesday, June 06, 2000 10:27 AM To: ITU-SG16@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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Klaghofer Karl ICN SIB NL D1