[OpenWrt Wiki] VLAN
https://openwrt.org/docs/guide-user/network/vlan/switch_configuration05.11.2021 · It works by adding a label (VLAN ID) on networking traffic, and using this label to route the traffic to keep isolated clients in different VLANs. To use a VLAN you need at least 2 devices supporting VLAN features (as any route requires at least 2 points), which is usually advanced routers, any OpenWrt device, and any self-respecting ...