H.323 (8.1) Phase A - Call Setup
Chris Wayman Purvis
cwp at ISDN-COMMS.CO.UK
Fri Jul 20 08:56:30 EDT 2001
Hi Pete (long time, no see!),
The sentence "An endpoint shall be capable of sending the Alerting message"
is surely bogus. For example in the case of an answering machine there can
be no requirement to be capable of sending Alerting - it must be acceptable
to make the decision on receipt of the setup message either to accept the
call (Connect) or not (ReleaseComplete). Similarly there is no absolute
requirement to be able to send CallProceeding.
I suggest you formally propose the removal of the offending sentence as an
item for the Implementor's Guide.
Peter Price wrote:
> 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 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 220.127.116.11
> (second para).
> Peter Price
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Dr Chris Purvis -- Development Manager
ISDN Communications Ltd, The Stable Block, Ronans, Chavey Down Road
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