Smart Connect - Creates a 'single' wireless network for your devices to connect to. Behind the scenes, the router automatically determines whether to connect a device to the 2.4 or 5 GHz band, thereby providing the best speed and range for each device and optimally distributing devices to each network.

Smart connect is enabled by default in Setting -> Wireless:


If disable smart connect, you’ll need to configure 2.4G/5G band individually.