[OpenSIPS-Users] Trouble SDP o-line

[Saúl Ibarra Corretgé]

Hi,

On Jul 22, 2013, at 3:09 PM, Julian Santer wrote:

> Hi,
> 
> we are using OpenSips 1.6.4 (starting with the migration to 1.8.x) with nat_traversal module and Mediaproxy 2.5.2.
> The Media at the moment will be relayed over the Mediaproxy only if it is necessary.
> 
> For the routing to PSTN we have two carriers.
> One of them ignores the o-line in SDP the other not.
> 
> So we got problems with one of the carrier, when in the o-line is a private or invalid IP and also if the o-line is not the same as the c-line
> 
> Example:
> 
> OK:
> 	v=0
> 	o=root 2142162444 2142162444 IN IP4 $PUBLIC_IP
> 	s=call
> 	c=IN IP4 $PUBLIC_IP
> 
> KO:
> 	v=0
> 	o=user 15997790 15997790 IN IP4 $PRIVATE_IP
> 	s=call
> 	c=IN IP4 $PUBLIC_IP
> 
> But also if we relay over our Mediaproxy, only the c-line will be changed.
> 
> KO:
> 	v=0
> 	o=- 46755 32066 IN IP4 $INVALID_IP
> 	s=bjoraow
> 	c=IN IP4 $MEDIAPROXY_IP
> 
> Have I any possiblity to inject the o-line or shouldn't I do that?
> Will the change of the o-line break the signalization?
> Should the carrier ignore the IP in the o-line?
> 

The o line is not used for routing and shouldn't be changed. I have heard of providers who check for this, but it's incorrect, that's why MediaProxy doesn't do it. If you feel like modifying the mediaproxy OpenSIPS module yourself, the required changes should be pretty straightforward.


Regards,

--
Saúl Ibarra Corretgé
AG Projects