1. What are the functions of the loopback interface in voice gateways?
2. Since loopback interface is always up unless the router is broken, is it advisable to tie the interface which generates H323 traffic to the loopback interface?
The loopback interface is a virtual interface that is always up and available after it has been configured.
It not adivse to use Loopback interface for any Data Traffic as best practice. end the loopback again need to use other interface source to in and out for traffic.
it all depends on your network and how you configured, as per standard loopback interface meant to use for :