On the IPQ4019, there are typically two active Ethernet MACs. The way the driver works, one is "hard bound" to the "Internet" port (the label, not necessarily how you use it) and the other is hard bound to the "LAN" ports. This is done with VLAN 1 and VLAN 2. Using those two VLANs for anything but untagged on those ports is likely to be a problem. Configuration using LuCI is likely to be "challenging", at best. Editing the config files is my preference.
VLAN trunking on the Internet interface works quite well (for VLAN IDs other than 1 and 2), tagged on both the CPU port and the Internet port of the switch. I have not tried on the LAN ports, but I would expect that it works there as well. (I use the Internet port for my VLAN trunk.)
If you want to bridge between the Internet and LAN ports, then you need to configure it in three places:
- Set up the VLAN on the switch for the Internet port (tagged, for example) and the CPU (tagged)
- Set up the VLAN on the switch for the LAN ports (untagged, for example) and the CPU (tagged)
- Bridge eth0.NNNN and eth1.NNNN