Sending the "empty capability set" in the first TCS

Paul Long plong at IPDIALOG.COM
Wed Apr 4 14:30:30 EDT 2001


Frank,

But it was also noted that an EP could send an "almost empty" TCS. Don't
send a capability table or descriptors but do send H.225.0 mux caps even if
it is essentially null. That will distinguish it from a truly empty TCS and
therefore permit you to send it as the first TCS. This is not to say that
some implementations still won't get confused by the almost empty TCS, but
at least you'll be right. :-)

Paul Long
ipDialog, Inc.

-----Original Message-----
From: Mailing list for parties associated with ITU-T Study Group 16
[mailto:ITU-SG16 at mailbag.cps.INTEL.COM]On Behalf Of Paul E. Jones
Sent: Wednesday, April 04, 2001 12:00 PM
To: ITU-SG16 at mailbag.cps.INTEL.COM
Subject: Re: Sending the "empty capability set" in the first TCS


Frank,

It is better not to get into situations where you wait for the other end to
do something: you will ultimately end up waiting for long periods of time.

It is far better to send your capability set immediately after the H.245
control channel is open.

The first message shall *not* be an empty TCS.  Through discussions last
week, it was clear that a number of vendors' implementations would break as
a result of that.  It is currently not valid.

Paul

----- Original Message -----
From: "Frank Derks" <frank.derks at PHILIPS.COM>
To: <ITU-SG16 at mailbag.cps.INTEL.COM>
Sent: Wednesday, April 04, 2001 5:56 AM
Subject: Sending the "empty capability set" in the first TCS


> Suppose that, after having established a call with a remote party, I
> want the remote party to send its capability set, but do not yet want
> to send my own capability set. If I am the one that established the
> H.245 Control Channel, I can imagine that the establishment itself
> does not necessarily trigger the remote party to send its capability
> set (although it could), but that the reception of a TCS message does.
>
> If I now send a TCS message with an empty capability set, am I doing
> something that I shouldn't do, or is this perfectly alright and does
> this trigger the remote party to send its capability set?
>
> Regards,
>
> Frank
>
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