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

A redundancy port is used for high availability and failover between two WLCs, not for normal client traffic forwarding.

A console port is used for direct, out-of-band management and initial configuration of the WLC, not for passing access-point data traffic.

The distribution system (DS) port, often labeled as a service port or management port in some contexts but specifically referring to the data plane, is the interface on the WLC that connects to the network's switches. This port carries the aggregated client data traffic from all associated access points back into the wired network infrastructure.

A service port (sometimes called a management port) is typically used for out-of-band management, specific services, or sometimes for internal WLC processes, but the distribution system port is for aggregated access point data traffic.