[SIPForum-discussion] 183 Session Progress without SDP

[Tomasz Zieleniewski]

UAS may send SDP in 183 Session Progress response
but under one condition that SDP is the same as in
final 2xx response to that INVITE.
UAC must then treat those media description as the final one.
There is no such rquirement to ingnore SDP if 100rel extension is not supported.

2009/4/10 Sunny <guangu.he at gmail.com>:
> This situation is very strange! I think is wrong, according to RFC3264 and
> other RFC, there is no option tag 100rel
> in the Supported Header, the UAS will not send responds with SDP.
> if the responds had SDP, UAC MUST ignore the SDP of the message
>
> 2009/4/10 Manish Aggarwal <maaggarwal at gmail.com>
>>
>> Multiple provisional responses is allowed as per the protocol spec.
>> This can be used to create an early dialogue.
>>
>> A UAS will send this, when its taking long time to process INVITE (and
>> before sending 200 OK).
>>
>> Have heard of this behavior before though.
>>
>>
>> -Manish
>>
>> On Thu, Apr 9, 2009 at 12:26 PM, nitin kapoor <nitinkapoorr at gmail.com>
>> wrote:
>>>
>>> Dear All,
>>>
>>> We are facing one problem where we are getting two 183 session for 1
>>> INVITE. UAC sending the INVITE to Switch and switch has forwarded the same
>>> invite to UAS. Then UAS first send the 183 Session progress without SDP and
>>> after 2 Sec its sends the another 183 Session Progress with SDP which is
>>> something i am not able to understand.
>>>
>>> 1) Can you please tell me on which cases UAS sends the two 183 Session
>>> progress like this.( with SDP & without SDP)?
>>> 2) Is this the correct behaviour?
>>>
>>> I checked this on RFC3261 and another sip pdf but unable to search it.
>>>
>>> Please find the attached Traces.
>>>
>>> Thanks
>>> Nitin Kapoor
>>>
>>> _______________________________________________
>>> This is the SIP Forum discussion mailing list
>>> TO UNSUBSCRIBE, or edit your delivery options, please visit
>>> http://sipforum.org/mailman/listinfo/discussion
>>> Post to the list at discussion at sipforum.org
>>>
>>
>>
>> _______________________________________________
>> This is the SIP Forum discussion mailing list
>> TO UNSUBSCRIBE, or edit your delivery options, please visit
>> http://sipforum.org/mailman/listinfo/discussion
>> Post to the list at discussion at sipforum.org
>>
>
>
>
> --
> Thanks
>
> Sunny
> --------------------------------------------------------------
> Skype:Guangwu.He
> --------------------------------------------------------------
>
> _______________________________________________
> This is the SIP Forum discussion mailing list
> TO UNSUBSCRIBE, or edit your delivery options, please visit
> http://sipforum.org/mailman/listinfo/discussion
> Post to the list at discussion at sipforum.org
>
>