On TD26 - Fast TCS and M/S negotiation in H.323v4
Plong at SMITHMICRO.COM
Tue May 30 10:37:39 EDT 2000
The behavior is NOT not defined. In fact, an H.323v2 or v3 EP receiving a
Setup message containing both a fastStart and h245Control component _shall_
respond with ReleaseComplete, thus terminating the call. This is defined in
Q.931 (see below) and not otherwise countermanded by H.225.0 or H.323.
Further, it follows that an EP which does not terminate the call is not
compliant. Since the calling EP cannot know the version of the called EP
before it sends Setup, I recommend that this v4 "feature" be removed from
the Recommendation or at least deprecated and that it not be implemented.
18.104.22.168/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
Smith Micro Software, Inc.
From: Paul E. Jones [mailto:paulej at PACKETIZER.COM]
Sent: Monday, May 29, 2000 9:46 PM
To: ITU-SG16 at MAILBAG.INTEL.COM
Subject: Re: On TD26 - Fast TCS and M/S negotiation in H.323v4
Pete, Sasha, Francois, Dale, et al,
I have concerns about this document that differ from Pete's. However,
discussion on this document has started, I thought I might as well
my concerns now while the material is fresh on people's minds.
The issue has to do with the very first sentence of the proposal, which
to strike "shall not" and replace it with "may". So, V2 devices shall
send a fastStart element and an H.245 message in SETUP, but V4 may.
seems to be a serious backward compatibility issue. If a V2 device were
receive a SETUP containing fastStart and an encapsulated H.245 message,
would it do? I believe the behavior is not defined.
Would somebody like to comment?
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