@Hornet
It’s possible to connect to your own firewall over P2P fiber, (1Gbit) e.g the non XGS-PON, This is the wholesale interface that runs on the Swisscom BBCS platform, you just need to buy a SFP module (or pull the one out of the sunrise modem) and set on the WAN interface as follows:
VLAN ID 10 and + DHCP option 60: dslforum.org,Fast5360-sunrise (can be anything)
This will get you the correct IP
Google around and you can find others that do it. but be aware, there isn’t much reliable reports of people bringing up SFP+ XSG-PON based WAN’s with there own modems as the ONT needs to be supported by the ISP,
I did not upgrade to 10Gbit simple to keep that support
if you do some research to understand the terms will help
