[SIPForum-discussion] Ringing / Session Progress (180/183)

[Herve Jourdain]

Hi,

My personal understanding is that you can get - or not - SDP for a data
stream in both 180 and 183 responses.

I think that if SDP is present, and you support the codec(s) present in it,
you should play the RTP stream, and if already generating local tone then
stop and play it. But I'm not sure this is mandatory...

And in case 180 or 183 come without SDP inside, you should generate local
ring tone, at least for 180. I would also personally do it for 183, but I
don't think it's that straightforward...
For what I could see so far, 183 seemed to be used mostly when trunking with
PSTN or other kinds of network, but then it usually came with a SDP, so it
was possible to play the tones received.
And in the cases it didn't come with SDP, it was usually more or less
synonymous to 180, so it was safe to play local ring tone...

But again, personal experience only, so...

Regards,

Herve

-----Original Message-----
From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of Donald Lee
Sent: jeudi 10 janvier 2008 09:15
To: Ramesh Chauhan
Cc: discussion at sipforum.org
Subject: Re: [SIPForum-discussion] Ringing / Session Progress (180/183)

I think you are partly right.
In many scenarios that after receiving the 183 response and doing a
PRACK procedure, another 180 response arrive. In this case, if the RTP
stream is also sending back, then the originator needn't generate
local ring back tone, otherwise it should play itself.

But according to my understanding and the practicality, no matter 183
or 180 responses that received, the UAC should not generate the ring
back tone if there is RTP stream incoming. It's color ring back tone.

On Jan 10, 2008 7:04 AM, Ramesh Chauhan <chauhan_delhi at yahoo.com> wrote:
> Hi,
>
> Can you please tell me the diference between Ringing(180) and Session
> progress(183).
>
> As per me, if we recieve Session Progress(183), then our media will start
> flowing from farend to us and from us to farend. and if we receive
> Ringing(180) then our device will generate his own ring on the phone.
> Eg:
> Session Progress(183):
> Callee                          SIPProxy                          Caller
>       ----------Invite--------------->
>
----------Invite--------------->
>                                            <--------Trying--------------
>       <--------Trying--------------
>                                            <--SessioProgress(183)-
>       <--SessioProgress(183)-
>       --------Here we will receive RTP from-------------------
>
> Ringing (180):
> Session Progress(183):
> Callee                          SIPProxy                          Caller
>       ----------Invite--------------->
>
----------Invite--------------->
>                                            <--------Trying--------------
>       <--------Trying--------------
>                                            <--ringing(183)------------
>       <--ringing(183)------------
>       --------Here our device will generate local ring-----------
>
> Am I correct ???????????/
>
>
> Regards
> Chauhan
>
>
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-- 
BR
Donald
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