Hi,
ProSBC has a nice registrar offload feature.
How about an inbound auth offload as well. 
There are multiple scenarios but a one that would allow “open sip trunk termination” is of most interest to us as a “carrier” feature.
This would request an auth on all INVITEs and BYEs on an “open” NAP. ProSBC would request and auth them internally without forwarding downstream.
At the moment creating open NAPs is painful for the “protected” softswitches behind ProSBC.
Paweł,