Which WLC port connects to a switch to carry normal access-point data traffic?

The distribution system (DS) port on a Wireless LAN Controller (WLC) is the primary port used to connect to the wired network (typically a switch). This port carries all normal access point (AP) data traffic, as well as management traffic between the WLC and the APs. It's essential for the WLC to communicate with the rest of the network infrastructure and forward client data. The redundancy port is used for high availability between two WLCs. The service port is for out-of-band management and troubleshooting. The console port is for local, direct access to the WLC's command-line interface.