[OpenSIPS-Users] Mediaproxy not updating with new SDPs

[Richard Revels]

No, you aren't overlooking anything.  What you describe is what happens.  User B answers with a different port in the 200 but the rtp continues to source from the same port.  The media relay just doesn't forward those packets.

I will try to get set back up to make some calls with this ALG device early this week and send the traces.

Richard


On Jul 30, 2010, at 4:35 AM, Saúl Ibarra Corretgé wrote:

> Hi Richard,
> 
> On 28/07/10 23:04, Richard Revels wrote:
>> No need to apologize.  I'm intruding on your time.  Just wanted to make sure I didn't sit in a spam filter for a week or anything.  :>
>> 
>> I found I had the same problem if I used use_media_proxy in the invite and reinvite.  However, since I am assured of the reinvite on every call from this source I just set a dialog flag in the invite to indicate I needed media proxy and waited to turn it on for the first time in the reinvite.  That is doing the job for now.  I suspect most users behind a Belkin home wifi router will cause this problem.  On the particular model we have been working with, there seems to be no way to turn off the SIP ALG so it is particularly irritating.
>> 
> 
> I looked at the SIP trace you sent but I can't see the reason why it 
> fails. User A sends the INVITE and after he sends the reINVITE (which 
> btw has the same media information) and user B answers with a different 
> port in the 200 OK.
> 
> We have code to handle this situation, the stream is reset and the 
> conntrack rule will be re-generated same as it did with the first 
> INVITE, IIRC.
> 
> Am I overlooking something here?
> 
>> Anyway, I have a working solution and if you find something that can fix this while still using engage_media_proxy() that will be even better.
>> 
> 
> You mentioned some ALG in the middle, can you confirm this doesn't 
> happen if you don't use this ALG device? How does the ALG craft the packets?
> 
> 
> Regards,
> 
> PS: Maybe you can find what the ALG does by capturing packets before and 
> after, just paste the differences. Ngrep is much nices to read btw ;-)
> 
> -- 
> Saúl Ibarra Corretgé
> AG Projects
> 
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