We have 2 CME setup, one in Montreal and one in Milan.
I have set the following rule in the Montreal's router:
dial-peer voice 37000 voip
progress_ind setup enable 3
session target ipv4:10.105.10.10
so each extension number that starts with 37xxx are forwarded to the CME setup in Milan through our permanent VPN connection.
However, sometime it works fine, sometime I have an 'unknown number' error...
Any idea why it would work randomly ?