Ah! The reasoning becomes clear - thanks Paul! Nevertheless, Pete is right. Given that the term "endpoints" can include answering machines this needs some careful rewording!
Regards, Chris
Paul E. Jones wrote:
Peter,
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.
Paul
----- Original Message ----- From: "Peter Price" PeterP@VEGASTREAM.COM To: ITU-SG16@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 before.
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
send
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
the
timeout for the sending endpoint.
I think the sentence should read: "If an endpoint can respond to a Setup message with a Connect, Alerting,
or
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
8.1.8.2
(second para).
Peter Price
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