H.323 (8.1) Phase A - Call Setup

[Peter Price]

Paul,

in fact, on further reflection, your second paragaraph highlights the error
in (8.1)
We both agree Alerting should be sent to the caller as soon as the callee's
phone is ringing but the text opens the door for someone to send Call
Proceeding and then not ever send Alerting.

It becomes clearer to me that the original intent was almost certainly
"If an endpoint can respond to a Setup message with a Connect within 4
seconds, it is not required to send the Alerting message."
Reference to Call Proceeding is incorrect and to Release Complete
irrelevent.

I'm not sure what should be done to clarify the purpose of Call Proceeding.
I think it being optional for terminal devices has led people to ignore its
correct use in gateways which are an important part of the network.  Perhaps
this need a separate thread.

Peter

> -----Original Message-----
> From: Peter Price [mailto:PeterP at VEGASTREAM.COM]
> Sent: 20 July 2001 14:05
> To: ITU-SG16 at mailbag.cps.INTEL.COM
> Subject: Re: H.323 (8.1) Phase A - Call Setup
>
>
> Paul,
>
> I forgot to say that I agree with your second paragraph with
> the proviso
> that it might take more than 4 seconds to send the Alerting.
> Call Proceeding is not a substitue for Alerting its just an
> indication that
> the caller should not give up too quickly.
>
> Pete
>
> > -----Original Message-----
> > From: Paul E. Jones [mailto:paulej at PACKETIZER.COM]
> > Sent: 20 July 2001 12:48
> > To: ITU-SG16 at mailbag.cps.INTEL.COM
> > Subject: Re: H.323 (8.1) Phase A - Call Setup
> >
> >
> > 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 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
> > > 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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> >
> >
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