Subject: RE: [Sip] Local vs. Remote ringback on 180

From: [email-masked]
Date: Mon, 17 Jun 2002 08:19:00 -0600

Jason Bach wrote:

Please be aware that in some service provider enviroments, 183 /w SDP is the
prefered method of producing ringing given the fact that the alternative,
180 /wo SDP, makes for a clipping condition when using the 200 OK to
iniciate RTP cut through. 

Regards, 

-----Original Message-----
From: Flemming Andreasen [mailto:[email-masked]] 
Sent: Sunday, June 16, 2002 4:43 PM
To: Adam Roach
Cc: 'Christer Holmberg'; Mark Watson; [email-masked]
Subject: Re: [Sip] Local vs Remote ringback on 180

Adam Roach wrote:

> No.
>
> No, no, no, no, no.
>
> If you know there is user alerting going on, use 180.
>
> Sending 183 and playing in-band ringback is not a
> generally acceptable solution; you're overriding
> the calling party's user interface's rendering of
> "remote party is being alerted." Their client may
> very well not render this using audio at all.

Could you point me to where in SIP this is stated ? Also, how come the unify
draft (in Figure 10) contains an example that explicitly uses 183 for inband
ringback ? The call-flows draft shows this as well.

>
> Think of the interactions between abusing 183 this
> way and, say, a deaf user.
>

I would assume that most deaf users would be using a relay or transcoding
service of some kind (e.g TDD) rather than having a plain old audio
telephone conversation, and hence I'm not sure it makes much difference in
that case.

-- Flemming

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_______________________________________________
Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [email-masked] for questions on current sip
Use [email-masked] for new developments on the application of sip