In a Cisco SD-Access wireless deployment, the roaming method used when a user moves from one access point to another on a different access switch using a single Wireless LAN Controller (WLC) is known as inter-xTR roaming. This method involves the use of Extended Node (xNode) which acts as a Remote Edge Node (REN) to facilitate seamless roaming across different access switches while maintaining the user's session and security context. https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/config-guide/b_wl_16_10_cg/mobility.html