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

[Dave Walker]

In Q.931, the user-user IE is typically optional, so the clause that
Paul Long's been quoting wouldn't apply.  However, since H.323 makes
the UUIE mandatory, it *does* apply in the case under discussion.
I think that the statement contained in TD-26, that it preserves
backwards compatibility, is completely wrong.  The correct statement
should have been that it doesn't break implementations known to the
authors.  I agree with Paul that we should try to develop a better
solution.

Regards,

Dave Walker
SS8 Networks
Ottawa, Canada


Paul Long wrote:
>
> Francois,
>
> The UUIE _is_ a Q.931 IE, 5.8.6.2/Q.931 does not exclude this IE, and
> neither H.225.0 or H.323 address the issue of how to handle a UUIE--or any
> other IE, for that matter--with invalid content, therefore the behavior
> defined in Q.931 is normative for H.323.
>
> _All_ of Q.931 is an "ISDN thing," so what's your point?
>
> Finally, there is much in Q.931 that H.323 does not reference, but that does
> not invalidate the parts of Q.931 that H.323 references.
>
> Paul Long
> Smith Micro Software, Inc.
>
> -----Original Message-----
> From: Francois Audet [mailto:audet at NORTELNETWORKS.COM]
> Sent: Thursday, June 01, 2000 7:34 AM
> To: ITU-SG16 at MAILBAG.INTEL.COM
> Subject: Re: On TD26 - Fast TCS and M/S negotiation in H.323v4
>
> > 5.8.6.2/Q.931: When a SETUP or RELEASE message is received
> > which has one or
> > more mandatory information elements with invalid content, a
> > RELEASE COMPLETE
> > message with cause No. 100, “invalid information element
> > contents” shall be
> > returned."
>
> My understanding of this statement is that it is meant to cover
> Q.931 elemements themselves, NOT UUIE content. As far as Q.931 is
> concerned, the User-user information element can be coded in
> whatever way we want. It is an ISDN thing that was carried over
> in H.225.0.
>
> So, my take is that this section is completely irrelevant to the
> H.245 tunnelling (or in fact H.245 in general). Also, it talks about
> a message (RELEASE) that is not even supported in H.225.0.
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 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