A wireless LAN controller (WLC) is a network device used to monitor and manage wireless access points in an organization.
WLCs are generally used in combination with the Lightweight Access Point Protocol (LWAPP) to manage light-weight access points in bulk by the network administrator or network operations center.
The WLAN controller automatically handles the configuration of wireless access-points.
It centralizes wireless network infrastructure and handles bandwidth allocation to the access points (APs).
Before the use of WLCs were widespread, APs had to handle connections individually, leading to unstable data links and poor connections.