During a client roaming event, which device is responsible for communicating the new Layer 2...

 During a client roaming event, the Wireless LAN Controller (WLC) is responsible for communicating the new Layer 2 Endpoint ID (EID) mapping of a wireless supplicant to the fabric domain. The WLC acts as a mobility orchestrator within the Cisco Digital Network Architecture (DNA) to ensure seamless roaming and connectivity. References: Designing Cisco Enterprise Wireless Networks (ENWLSD 300-425)

https://www.cisco.com/c/dam/en/us/td/docs/cloud-systems-management/network-automation-and-management/dna-center/deploy-guide/cisco-dna-center-sd-access-wl-dg.pdf