Subject: [rtcweb] Same answer in a provisional and a final response

From: Gonzalo Camarillo <[email-masked]>
Date: Tue, 15 Nov 2011 10:38:44 +0800

Hi,

with respect to today's discussion during the face-to-face session about
whether a SIP UAS needs to place the same answer in a final response as
it placed in a previous provisional response, this is the relevant text
in RFC 3261:

http://tools.ietf.org/html/rfc3261#page-80

        "If the initial offer is in an INVITE, the answer MUST be in a
         reliable non-failure message from UAS back to UAC which is
         correlated to that INVITE.  For this specification, that is
         only the final 2xx response to that INVITE.  That same exact
         answer MAY also be placed in any provisional responses sent
         prior to the answer."

Cheers,

Gonzalo

---

From: Randell Jesup <[email-masked]>
Date: Mon, 14 Nov 2011 23:30:35 -0500

>           answer MAY also be placed in any provisional responses sent

Yes, though I'll note that differing 200 OK's from 18x provisionals is 
in my experience far more common than identical 200 OK's.  (As Cullen 
alluded to.)

-- 
Randell Jesup
[email-masked]

---

From: Roman Shpount <[email-masked]>
Date: Mon, 14 Nov 2011 23:50:02 -0500

On Mon, Nov 14, 2011 at 11:30 PM, Randell Jesup <[email-masked]>wrote:

>> http://tools.ietf.org/html/**rfc3261#page-80<http://tools.ietf.org/html/rfc3261#page-80>
>>
> Yes, though I'll note that differing 200 OK's from 18x provisionals is in
> my experience far more common than identical 200 OK's.  (As Cullen alluded
> to.)
>
>
The above mentioned quote from RFC 3261 only means that the same SDP must
be present in 200 OK and 18x provisional for the same dialog. If you have
an early dialog and different final dialog (different to tags in 18x and
200), it is legal, and, in fact, expected to have different SDPs.
_____________
Roman Shpount

---

From: "Ravindran, Parthasarathi" <[email-masked]>
Date: Tue, 15 Nov 2011 04:48:19 +0000

Hi Gonzalo,

Agreed. IIUC, RTCWeb ROAP slide was discussing about forking issue wherein 
it is possible to have different answer in provisional (UAS1) and final 
response (UAS2). In case the callflow slide is shown with different to-tags,
it may be very clear.

Thanks
Partha 

>-----Original Message-----
>From: [email-masked] [mailto:[email-masked]] On Behalf
>Of Gonzalo Camarillo
>Sent: Tuesday, November 15, 2011 10:39 AM
>To: [email-masked]
>Subject: [rtcweb] Same answer in a provisional and a final response
>
>Hi,
>
>_______________________________________________
>rtcweb mailing list
>[email-masked]
>https://www.ietf.org/mailman/listinfo/rtcweb