AT&T's IP passthrough isn't a true layer 2 bridge. It's a NAT hack that allows the same public IP(v4) address to be used by the ONT/router and your router.
As such, you're limited to the resources of the ONT/router. For example, the number of hardware-accelerated flows is limited (~8000 I believe? I can't find a source right now).
As such, you're limited to the resources of the ONT/router. For example, the number of hardware-accelerated flows is limited (~8000 I believe? I can't find a source right now).