Conflicting text in H.323 concerning the requirement for esta blishing a H.245 control channel??

[Chris Wayman Purvis]

Charles,

> Part of  establishing a "point-to-point" call involves opening 2 TCP
> connnections using the Fast Connect procedure as you described it.  If that
> is the case, then the extract from H.323v2 below is misleading(I believe).
>
> H.323v2: 8.1.7 Fast Connect Procedure
>
> "..... The Fast Connect procedure allows the endpoints to establish a basic
> point-to-point call with as few as one round-trip message exchange, enabling
> immediate media stream delivery upon call connection."

I don't see a conflict between that quotation and what I said.  You have a
basic point-to-point call quickly.  Media flow.  Then you set up the H.245
session with all reasonable speed WHILE MEDIA ARE FLOWING.  So you get your
media channels set up as a result of fastConnect, and THEN negotiate other
capabilities, master-slave etc.

Oh, and there's no need for a second TCP connection anyway - use H.245
tunnelling.

Regards,
Chris


>> -----Original Message-----
>> From: Chris Wayman Purvis [mailto:cwp at ISDN-COMMS.CO.UK]
>> Sent: Tuesday, March 20, 2001 5:47 PM
>> To: ITU-SG16 at MAILBAG.INTEL.COM
>> Subject: Re: Conflicting text in H.323 concerning the requirement for
>> esta blishing a H.245 control channel??
>>
>>
>> Charles,
>>
>> It does NOT defeat ANY of the stated aims of FastConnect.
>> These aims were to get agreed media channels in both
>> directions open as
>> quickly as possible.  Doing FastStart AND H.245 gives you your media
>> quickly, and means you have the power of H.245 thereon.
>>
>> In-band DTMF transfer may be used.  If you happen to be using
>> a codec that
>> supports it.  If you assume it when you're using an
>> unsuitable codec you'll
>> have a problem.  Which is a reason for using H.245 capability
>> negotiation.
>>
>> Regards,
>> Chris
>>
>> Agboh, Charles wrote:
>>
>>
>>> which defeats the whole point of having a Fast Connect
>>
>> procedure (FS +
>>
>>> H.245).  Why isn't in-band- DTMF transfer used instead (in FS)?
>>>
>>> -Charles
>>>
>>>
>>>
>>>> -----Original Message-----
>>>> From: Frank Derks [mailto:frank.derks at PHILIPS.COM]
>>>> Sent: Tuesday, March 20, 2001 4:40 PM
>>>> To: ITU-SG16 at MAILBAG.INTEL.COM
>>>> Subject: Re: Conflicting text in H.323 concerning the
>>>
>> requirement for
>>
>>>> establishing a H.245 control channel??
>>>>
>>>>
>>>> Chris,
>>>>
>>>> I thought I was being clear enough, so let me try again.
>>>> 6.2.8/H.323 states
>>>> that an enpoint must open one (and exactly one) H.245 control
>>>> channel. When
>>>> Fast Connect is being used, I assume that the intention is
>>>> that no such control
>>>> channel is opened.
>>>>
>>>> To be compliant with 6.2.8/H,323 I would have to open a H.245
>>>> control channel
>>>> irrespective of which type of H.245 procedures I will be
>>>> using. So if I intend
>>>> to use Fast Start (and assuming that the other party also
>>>> supports this), I
>>>> still have to open a H.245 control channel.
>>>>
>>>> Frank
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> cwp at isdn-comms.co.uk on 20-03-2001 15:17:14
>>>> To:     Frank Derks/HVS/BE/PHILIPS at EMEA2
>>>> cc:     ITU-SG16 at mailbag.cps.INTEL.COM@SMTP
>>>> Subject:        Re: Conflicting text in H.323 concerning the
>>>> requirement for establishing a H.245 control channel??
>>>> Classification:
>>>>
>>>> Frank,
>>>>
>>>> Why do you consider this text to be "conflicting"?
>>>> Specifically, with what does it conflict?
>>>>
>>>> Regards,
>>>> Chris
>>>>
>>>>
>>>>
>>>>> 6.2.8/H.323 states: "The endpoint shall establish exactly
>>>>
>> one H.245
>>
>>>>> Control Channel for each call that the endpoint is
>>>>
>>>> participating in."
>>>>
>>>>
>>>>> 8.1.7/H.323 never states that when Fast Connect is being
>>>>
>> used such a
>>
>>>>> control channel should be established. As far as I understand the
>>>>> mechanism this is only required to switch to "normal" H.245
>>>>
>>>> procedures.
>>>>
>>>>
>>>>> It would seem that section 6.2.8 should be rephrased to
>>>>
>>>> make clear that
>>>>
>>>>
>>>>> the H.245 control channel shall only be established when
>>>>
>>>> "normal" H.245
>>>>
>>>>
>>>>> procedures are being followed and not in the fast connect case.
>>>>>
>>>>> Frank
>>>>
>>>> --
>>>> Dr Chris Purvis -- Development Manager
>>>> ISDN Communications Ltd, The Stable Block, Ronans, Chavey Down Road
>>>> Winkfield Row, Berkshire.  RG42 6LY  ENGLAND
>>>> Phone: +44 1344 899 007
>>>> Fax:   +44 1344 899 001
>>>>
>>>>
>>>
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>>>> For help on this mail list, send "HELP ITU-SG16" in a message to
>>>> listserv at mailbag.intel.com
>>>>
>>>
>>>
>>>
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>>> For help on this mail list, send "HELP ITU-SG16" in a message to
>>> listserv at mailbag.intel.com
>>
>>
>> --
>> Dr Chris Purvis -- Development Manager
>> ISDN Communications Ltd, The Stable Block, Ronans, Chavey Down Road
>> Winkfield Row, Berkshire.  RG42 6LY  ENGLAND
>> Phone: +44 1344 899 007
>> Fax:   +44 1344 899 001
>>
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> For help on this mail list, send "HELP ITU-SG16" in a message to
>> listserv at mailbag.intel.com
>>


--
Dr Chris Purvis -- Development Manager
ISDN Communications Ltd, The Stable Block, Ronans, Chavey Down Road
Winkfield Row, Berkshire.  RG42 6LY  ENGLAND
Phone: +44 1344 899 007
Fax:   +44 1344 899 001

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
For help on this mail list, send "HELP ITU-SG16" in a message to
listserv at mailbag.intel.com