[SIPForum-discussion] Should session version in "o=" line be same for 180 ringing and 200 ok message?

[Stephen James]

A strict reading of RFC 3261 indicates that the sending of the BYE is not 
correct.

The UAC MUST treat the first session description it receives as the answer, and 
MUST ignore any session descriptions in subsequent responses to the initial 
INVITE.

So it should really ignore the SDP in the 200 OK.

The reason that the UAC is probably failing the call is this from 3261

Once the UAS has sent or received an answer to the initial offer, it MUST NOT 
generate subsequent offers in any responses to the initial INVITE.  This means 
that a UAS based on this specification alone can never generate subsequent 
offers until completion of the initial transaction.

The change in the o= line means new SDP and therefore an offer.


 
Stephen James 
sjames_1958 at yahoo.com
 
We are not princes of the earth, we are the descendants of worms, and any 
nobility must be earned.





________________________________
From: Vijay Tiwari <vijay11tiwari at gmail.com>
To: sid <sid77sharma77 at gmail.com>
Cc: "discussion at sipforum.org" <discussion at sipforum.org>
Sent: Fri, May 17, 2013 10:44:44 AM
Subject: Re: [SIPForum-discussion] Should session version in "o=" line be same 
for 180 ringing and 200 ok message?


Hello Sid 

If there is no change in 180 ringing and 200 ok SDP then "o=" line should be 
same. 

Regards
vijay 



On Thu, May 16, 2013 at 1:53 AM, sid <sid77sharma77 at gmail.com> wrote:

Hi,
>Yes, both 180 riniging and 200 ok carries sdp information. but I did not find 
>any change.
>
>Sent from my iPod
>
>On 15-May-2013, at 9:49 PM, Kovács György <gykovacs.datanet at gmail.com> wrote:
>
>
>If the SDP has changed the version number in origin line must be incremented, it 
>is normal behavior. 
>
>>Are you sending 200 OK with SDP? Is there any difference between the 180 Ringing 
>>SDP and the 200 OK SDP?
>>Maybe the problem is with the SDP (probably there were different codec 
>>settings?), not the origin line itself.
>>
>>
>>-- 
>>Kovács György  
>>On Wed, 2013-05-15 at 13:08 +0530, siddharth sharma wrote: 
>>
>>Hi Guys,
>>> 
>>>I have one scenario, where my carrier is complaining that their calls are 
>>>getting disconnected after few milliseconds.
>>>According to their analysis, they are saying that session version in "o=" line  
>>>is not same as in 180 ringing and 200 Ok message.
>>>Because of this, they are sending BYE message.
>>> 
>>>Is this valid reason?
>>> 
>>>I have checked message, I have not found any difference. 
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>
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