Hello,
180 and 183 have the same To-Tag, the first one contain SDP and connects early
media (announcement/in-band) that A-side SIP device hears, but no indication
that announcement has stop is received, then 180 Ringing without SDP is
received from A-side SIP device but the device does not generates local ring
back tone.
Is it a limitation of the device if it does not generate local ring back tone
in that case,
is a 199 needed in this case since we have one dialog??
Also according to standards 180 Ringing without SDP will trigger local ring
back tone
RFC3960:
With this in mind, a UAC should develop its local policy regarding
local ringing generation. For example, a POTS ("Plain Old Telephone
Service")-like SIP User Agent (UA) could implement the following
local policy:
1. Unless a 180 (Ringing) response is received, never generate
local ringing.
2. If a 180 (Ringing) has been received but there are no incoming
media packets, generate local ringing.
3. If a 180 (Ringing) has been received and there are incoming
media packets, play them and do not generate local ringing.
Note that a 180 (Ringing) response means that the callee is
being alerted, and a UAS should send such a response if the
callee is being alerted, regardless of the status of the early
media session.
Is there a known limitation on sip devices that if an early-media inband
information is connected ( in our case announcement) then afterwards it cannot
generate local ringing???
Thank you very much,
Despina
> Date: Wed, 9 Oct 2013 11:10:52 -0400
> From: [email protected]
> To: [email protected]
> Subject: Re: [Sip-implementors] sip device ring back tone
>
> On 10/9/13 10:39 AM, Despina Kitsou wrote:
> >
> > Hello,
> >
> > I have the following issues regarding the :
> >
> > Firstly, A-SIP subscriber call to a TDM subscriber that has been ported now
> > to a C-SIP subscriber.So A-SIP subscriber receives an 183 Session progress
> > with SDP in order for an announcement to be heard that this subscriber is
> > ported and that you call is being diverted, then C-SIP subscriber is
> > reached and sent 180 Ringing without SDP but my A-SIP device does not
> > generate local ringing,
> > Is that a limitation of the sip device to Switch Between Early Media and
> > Local Ringing???PLEASE HELP ME!!
>
> More detail would be helpful.
>
> Are the 183 and 180 on different early dialogs (different to-tags), or
> the same one?
>
> Does the early media from the 183 continue after the 180 is received, or
> does it stop?
>
> If its all on one early dialog, then it should be clear (based on the
> 180) to the caller that the call is ringing. While media is being
> received it should be played. If it stops, then the caller ought to
> generate local ringback.
>
> If these are on two different early dialogs, then it is tricky. The
> caller doesn't know which of the two dialogs will eventually be
> answered. It also doesn't know which dialog the media is coming from. So
> the device has to take a lot of discretion in what it does. There is no
> one right answer in this case. I'd be inclined to say it ought to behave
> the same as if there was only one early dialog.
>
> The callee could help this along a bit by returning a 199 () on
> the dialog containing the 183 to indicate that is done.
>
> Thanks,
> Paul
>
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