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List:       sip-implementors
Subject:    Re: [Sip-implementors] 180 Ringing with SDP
From:       "Gupta, Ajay" <ajgupta () verisign ! com>
Date:       2006-01-25 10:56:46
Message-ID: 51A01D83FA287B469512A695F559B92FE260A8 () DUL1WNEXMB03 ! vcorp ! ad ! vrsn ! com
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The SDP in 180 response could be used for multiple reasons e.g. for
playing a ringtone from the far end switch/GW or for playing early media
announcements and collecting digits etc without connecting the calls

However the SDP being carried in messages which belong to one
transaction should follow the offer-answer model (see RFC 3264 for
details) Sending SDP in 180 response is optional but if sent should be
sent reliably (see RFC 3262 for details)

Ajay

-----Original Message-----
From: sip-implementors-bounces@cs.columbia.edu
[mailto:sip-implementors-bounces@cs.columbia.edu] On Behalf Of Paulo de
Arruda Borelli
Sent: Tuesday, January 24, 2006 7:49 PM
To: sip-implementors@cs.columbia.edu
Subject: [Sip-implementors] 180 Ringing with SDP

Hi,

 

Why would an UAC send 180 Ringing with SDP? If it's supposed to use
early media, then 183 Session Progress is more appropriate, right?

 

In my understanding, 180 with SDP is contradictory. 180 means: "play a
local ringback tone". But the SDP content means: open the media path (in
my scenario, the original INVITE message did include SDP too).

 

So what is the reason for using 180 with SDP in the scenario bellow?

INVITE/SDP from A to B

180/SDP from B to A

200/SDP from B to A

 

Thank you,

 

Paulo A. Borelli
Gerente de Engenharia / Engineering Manager TMais S.A.
VoIPMais: +55-11-2626-1080, r. 1136
Cell: +55-11-9282-5990
 <BLOCKED::mailto:pborelli@tmais.com.br> pborelli@tmais.com.br
<BLOCKED::http://www.tmais.com.br> www.tmais.com.br

 

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