Iñaki Baz Castillo wrote:
> El Miércoles, 10 de Junio de 2009, Dale Worley escribió:
>> And a UAC might want to display the reason phrase, so you could use
>
> Do you mean that the UAC could display the reason phrase in *English*? IMHO a
> standarized code or "string" should be needed for this instead of a custom
> string in English.
You mean everybody doesn't speak English? :-)
Actually, *in theory*, you can put Accept-Language:es into your INVITE,
and then the text messages in the response ought to be written in Spanish.
(And of course everybody's SIP implementation does that. :-)
Practically speaking, if you want the caller to display some indication
with a specific semantic then you do need some signaling that coveys
that semantic. The 182, ignoring the reason phrase, comes *close* -
close enough that IMO it would be reasonable for a UA to display some
message that the user would reasonably interpret as call waiting.
To get more specific than that, I have, for quite some time, been
promoting the concept of using Alert-Info with a URN, and defining URNs
with specific semantics. Having one with a "call waiting" semantic would
be quite reasonable. Alert-Info in a response is already defined, so
this is not an abuse. The main problem preventing use of Alert-Info with
URIs has, IMO, been one of trust - you don't know whether you are going
to get something offensive or dangerous. Using URNs with agreed upon
semantics eliminates that issue.
Thanks,
Paul
>> SIP/2.0 182 Call waiting
>>
>>>> Another option would be a new response code:
>>>> "184 Call-Waiting"
>>>> but it would be very complex to make it work with existing devices
>>>> which basically expect 180 and 183.
>> Any UA must be prepared to receive any 1xx response and perform
>> adequately.
>
> Sure, but do they do? :)
>
> Thanks.
>
>
>
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