[OpenSIPS-Users] Prevent re-INVITE to T.38

Jeff Pyle jpyle at fidelityvoice.com
Mon Mar 17 17:27:02 CET 2014


Excellent!  Apparently I mis-read this part of the RFC.  Thanks.


- Jeff



On Mon, Mar 17, 2014 at 12:02 PM, Bogdan-Andrei Iancu
<bogdan at opensips.org>wrote:

>  Hi Jeff,
>
> Alice expects just a higher cseq number, not an increment with 1 or any
> step...just higher than the prev one :)
>
> Regards,
>
> Bogdan-Andrei Iancu
> OpenSIPS Founder and Developerhttp://www.opensips-solutions.com
>
> On 17.03.2014 17:52, Jeff Pyle wrote:
>
>  Hi Bogdan,
>
>  Let's say Bob reinvites Alice to T.38 through my proxy.  My proxy
> declines the reinvite.  That transaction has completed and Bob has
> incremented his CSeq number.  Now, if Bob sends another in-dialog request
> (such as a BYE), the CSeq is one higher than Alice is expecting.  That's
> not a problem?  Alice won't reply with a 400?
>
>
>  - Jeff
>
>
>
> On Mon, Mar 17, 2014 at 11:24 AM, Bogdan-Andrei Iancu <bogdan at opensips.org
> > wrote:
>
>>  Hi Jeff,
>>
>> This is a false problem - you can simply decline the re-INVITE without
>> breaking anything - each side has its own cseq number, and they are
>> independently increased when a party is generating a new requests.
>>
>> So, just decline it and that's it !
>>
>> Regards,
>>
>> Bogdan-Andrei Iancu
>> OpenSIPS Founder and Developerhttp://www.opensips-solutions.com
>>
>>  On 11.03.2014 19:42, Jeff Pyle wrote:
>>
>>   Hi Alexander,
>>
>>  To detect the "image" session in the SDP, you are thinking the same way
>> that I am.  The problem I see is how to actually reject the re-INVITE.  If
>> I were to do something like a sl_send_reply("488", "Not Acceptable Here"),
>> that would work in the moment, but the CSeq values would be increased by
>> one on side compared to the other.  That sounds to me like a recipe for
>> problems in future in-dialog transactions (like BYE).
>>
>>
>>
>>  - Jeff
>>
>>
>>
>>
>> On Tue, Mar 11, 2014 at 12:58 PM, Alexander Mustafin <
>> mustafin.aleksandr at gmail.com> wrote:
>>
>>> Hi, Jeff.
>>>
>>>  Maybe stream_exists(regexp) in sipmsgops module will be useful for
>>> you.
>>>
>>>   Best regards,
>>> Alexander Mustafin
>>> mustafin.aleksandr at gmail.com
>>>
>>>
>>>
>>>
>>>  11 марта 2014 г., в 20:07, Jeff Pyle <jpyle at fidelityvoice.com>
>>> написал(а):
>>>
>>>    Hello,
>>>
>>>  Is there anything I can do at the proxy level to prevent a dialog from
>>> reinviting to to T.38?  I think I could detect the T.38 attributes easily
>>> enough and respond with a 488, although I'm concerned the CSeq values would
>>> be out of sequence for the next transaction that did make it through the
>>> proxy to the far end.  That could cause a problem, no?
>>>
>>>  Is this something that requires a B2BUA?  Is it possible from within
>>> the OpenSIPS B2B modules to do SDP inspection of any sort?
>>>
>>>
>>>  - Jeff
>>>
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>>
>>
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>
>
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