[ Router 192.168.0.1 ]
        |
   LAN 192.168.0.0/24
        |
[ VirtualBox (bridge) ]
        |
[ nic0 ]   ← NIC virtual
        |
[ vmbr0 ]  ← switch virtual + IP
        |
[ Proxmox Host 192.168.0.16 ]
        |
[ VMs / LXC ]