[SOLVED] Setting up OpenWrt with VLANs on Unifi 6 Lite

I installed OpenWRT 21.02.2 on a Unifi 6 Lite.
The instructions on the wiki/site worked well for that.

I then tried to set up the system as a dumb access point with two SSID networks. One network is the 5ghz and the other is 2ghz.

I could not figure out how to set up these networks as VLANS.

I tried using my old knowledge about Linux and tried creating interfaces eth0.1 etc. for each VLAN.

This didn't work. In fact, when I did tcpdump on the packets from my other router box, I noticed that the packets were mangled.

I wan't aware about the new DSA network architecture in the kernel.
I think that is why things didn't go well.

Hopefully, this guide will be helpful to others doing a similar set up.

Here is what I did to configure my setup.
Again, I have 1 untagged network for openwrt. I have two SSIDs for 5ghz and 2.4ghz wireless. This is all set up as a 'dumb' ap mode.

I will only cover what I did to configure the VLANs.

In the web interface/LUCI, I went to Network > Interfaces.
Go to the devices tab.

I left the 'br-lan' alone as my management interface. It is not on a vlan.

Create two VLANS.
I called them lan.100 and lan.300. Their base device was the 'lan'

Create two bridge devices. Assign the respective VLAN to the 'Bridge ports' field for each bridge.
Example: 'IOTBridge' got 'lan.300'.

Now in Network > Interfaces, create two interfaces via 'Add New Interface'.
Give each a name and set them to 'unmanaged'.
Then assign the respective bridge device to the interface.

Now go to Network > Wireless
Disable the default SSIDs set up.
Add your wireless SSIDs for each radio.
Add the interfaces you just set up for each SSID in the 'Network' field.

Other than setting up your wireless passwords, etc... you should be good to go at this point.