Lan port or vlan for physical setting?

When I create an additional WAN interface:
In “Physical Settings”-Tab I can either select a port-mapped vlan (i.e br-lan.3 or br-lan.4) or I can directly select a port like “lan3” or “lan4”.

Can anyone tell me what the difference is?

Good afternoon,

As you have mentioned, the port mapped vlan (i.e br-lan.3 or br-lan.4) utilizes VLAN separation, not exposing your Lan or Wan traffic.

VLANs provide a logical separation layer, which is especially important in professional or multi-network environments.

Port-mapped VLAN (e.g., br-lan.3, eth0.3)The interface is tied to a specific VLAN ID, allowing logical separation of traffic even over the same physical port.|Use when you need to separate traffic for different networks or services on the same port.|

Direct Port (e.g., lan3, lan4) The interface is mapped directly to a physical port, without VLAN tagging. Use for simple setups where each port is dedicated to a single network or service.

Regards,
Arturas