[OpenSIPS-Users] Removing a VIA line required by Telco.

[David Gilbert]

Jeff Pyle wrote:
> David,
>
> As I understand it, a SIP proxy needs the Via lines to properly route.  It
> sounds like in your case you need to move Asterisk (or any B2BUA) forward in
> your diagram to be the entity that communicates with your telco.  No Via
> lines, no proxy.  A B2BUA, however, by design hides the topology of the
> network behind it.  No extra Via lines.  Other SBC-class products do that as
> well but probably aren't worth the potential cost.
>
> Or, find a telco that sucks less.  Unfortunately that doesn't sound like a
> possibility.
>
>   
That's our current fallback position.  The issue is complex.  We're 
using the OpenSIPS proxy for two reasons: a) reliability (it's in a 
configuration with CARP and other fancy stuff)... and b) to divide 
billing.  The issue is that we "receive" multiple PRI with different 
parameters from the Telco and they require that be on a different IP for 
each one.  OpenSIPS makes that fairly easy.  Asterisk will only talk to 
one IP per installation (requiring multiple machines or virtualization).

Can't OpenSIPS be smart and remember the other VIA line as part of the 
"state" it keeps?  I know that the solution we replaced (run by another 
company) used a switch that didn't handle the media and yet still 
managed to deliver only one VIA line to this telco.