Wireless - WLC trunk connection to core
In a typical wireless network where a Wireless LAN Controller (WLC) is used, best practice dictates that the WLC will have a trunk connection to the core network which includes all of the VLANs that correspond to the SSIDs that they serve, similar to the following diagram.
Notice that the WLC1 has a trunk connection to the core which includes VLANs 10, 20, and 30, each of which corresponds to an SSID in the network.
This is best practice because it allows the core network to perform the routing between such networks. Alternatively, the WLC could perform routing, however this is not considered best practice, especially for larger networks.