The controller’s neighbor devices must also be properly configured to support LAG
When you enable LAG, all ports participate in LAG by default.
When you enable LAG, you cannot create interfaces with a primary port other than 29.When you enable LAG, all dynamic AP-manager interfaces and untagged interfaces are deleted, and all WLANs get mapped to the management interface.When you enable LAG, you can configure only one AP-manager interface because only one logical port is needed.When LAG is enabled, any change to the LAG configuration requires a controller reboot.Therefore, you can connect a controller in LAG mode to only one neighbor device. Only one LAG group is supported per controller. You cannot configure the controller’s ports into separate LAG groups.Keep these guidelines in mind when using LAG "Make sure the port-channel on the switch is configured for the IEEE standard Link Aggregation Control Protocol (LACP), not the Cisco proprietary Port Aggregation Protocol (PAgP)."Controller only supports the on mode of the LAG. LACP and PAgP are not supported on the controller Link to configure Etherchannel on switches Controller only supports the on mode of the LAG Hence, if you have LAG on WLC, then ETHERCHANNEL must be configured on the switch Wireless LAN Controller (WLC) FAQ you want to connect controller ports to different switches, LAG must be disabled, and you must configure one (1) AP Manager Interface for each WLC distribution port. The width of the data pipe on wlc must match with the width of the data pipe on the switch ! So, if you are combining physical ports of WLC, you must combine physical ports of the switch. In this document we will see important guidelines while using LAG - Link Aggregation. Cisco WLC Configuration Guide, Release 7.6-Restrictions for Link Aggregation.The controller’s neighbor devices must also be properly configured to support LAG.Keep these guidelines in mind when using LAG.Controller only supports the on mode of the LAG.