Which tunnel type allows clients to perform a seamless Layer 3 roam between a Cisco AireOS WLC and a Cisco IOS XE WLC?

CAPWAP (Control and Provisioning of Wireless Access Points) is the standard protocol used by Cisco wireless solutions for tunneling client traffic between APs and WLCs. This tunneling mechanism allows clients to maintain their IP address and session even when roaming across different APs connected to separate WLCs, ensuring seamless Layer 3 mobility.

IPsec is a suite of protocols for securing IP communications through authentication and encryption, but it is not the native protocol used for client data tunneling and roaming in Cisco wireless architectures.

VPN is a general term for secure tunnels, but it does not specify the particular protocol that facilitates seamless client mobility between Cisco WLCs.

Ethernet over IP (EoIP) is a tunneling protocol used to extend Layer 2 networks over Layer 3, but it is not the standard mechanism for client roaming between Cisco WLCs.