I facing a mayor problem setting up my connection properly.
I have the following setup:
ISP - VGV7510KW22 / O2 Box 6431 -2.Router - all devices in my network
I believe that chapter "9.8 Bridge mode for VDSL Connection - updated Dec’17" of LEDE Installation Guide for HH5A v1.62b.pdf on https://www.dropbox.com/sh/c8cqmpc6cacs5n8/AAA2f8htk1uMitBckDW8Jq88a?dl=0 should be a decent proposal, even though i would expect some difference due to the different hardware.
Do not thank me, thank @bill888, who I believe to be the author of that great installation guide. Sidenote if you still remember the tweaks required to make it work on your O2 Box, maybe you could summarize them in this thread, sort of as a service to others wanting to do the same?
Not sure what the manual recommends, but I basically used an additional port of the switch with a different VLAN tag as input from the LAN side (I changed the modem's subnet to 192.168.100.0/24 and added an new interface on the real router's wan interface using the same VLAN and hence can reach the modem easily through my router, but I digress)
Sidenote: I believe that openwrt trunk/master (and hence openwrt 18.5 as well) will use the interface name dsl0 instead of nas0 and ptm0 allowing to switch the link technology from adsl to vdsl and back without the need for reconfiguration...