H.323 (8.1) Phase A - Call Setup
Paul E. Jones
paulej at PACKETIZER.COM
Fri Jul 20 07:48:18 EDT 2001
Alerting was the intent. Call Proceeding not produce a ringing sound in the
caller's ear. H.323 devices have to be able to send an Alerting, though
they're not required to do so if they can send a Connect within 4 second.
The 4 seconds is the T303 timeout and the T303 timer is disabled when
receiving Alerting, too... not just Call Proceeding.
The ideas are related, but independent. What we have seen some folks do is
send a Call Proceeding to the caller and then nothing else until the
connect. The result is that the calling party hears silence for a very long
time: that's not good.
----- Original Message -----
From: "Peter Price" <PeterP at VEGASTREAM.COM>
To: <ITU-SG16 at mailbag.cps.INTEL.COM>
Sent: Friday, July 20, 2001 6:54 AM
Subject: H.323 (8.1) Phase A - Call Setup
> Hi folks,
> I think I may have found some incorrect text in H.323 8.1
> The same text appears in both V3 and V4 so I suspect nobody has commented
> In the paragraph beginning:
> "An endpoint shall be capable of sending the Alerting message. ..."
> it goes on to say:
> "If an endpoint can respond to a Setup message with a Connect, Call
> Proceeding, or Release Complete within 4 seconds, it is not required to
> the Alerting message. An endpoint sending the Setup message can expect to
> receive either an Alerting, Connect, Call Proceeding, or Release Complete
> message within 4 seconds after successful transmission."
> I believe the first sentence here should really be discussing the
> requirement to send a Call Proceeding (not Alerting) message.
> The period of 4 seconds in the last sentence is related to T303 which is
> specifically terminated by a Call Proceeding message in order to extend
> timeout for the sending endpoint.
> I think the sentence should read:
> "If an endpoint can respond to a Setup message with a Connect, Alerting,
> Release Complete within 4 seconds, it is not required to send the Call
> Proceeding message."
> This is then consistent with the use of Call Proceeding described in
> (second para).
> Peter Price
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