Explanation Link aggregation (LAG) is a partial implementation of the 802.3ad port aggregation standard. It bundles all of thecontroller's distribution system ports into a single 802.3ad port channel. Restriction for Link aggregation: + LAG requires the EtherChannel to be configured for 'mode on' on both the controller and the Catalyst switch. ... Reference: https://www.cisco.com/c/en/us/td/docs/wireless/controller/7-5/configuration-guide/b_cg75/b_cg75_chapter_0100