Which control-plane protocol does an SD-Access fabric use for endpoint mapping and resolution?

LISP (Locator/ID Separation Protocol) is the correct answer because SD-Access uses it as the control plane protocol for endpoint registration, mapping, and resolution. LISP separates the endpoint identifier (EID) from its routing locator (RLOC), allowing for scalable mobility and host reachability within the fabric. DHCP is incorrect because it's used for IP address assignment, not endpoint mapping. VXLAN is incorrect because it's the data plane encapsulation protocol in SD-Access, responsible for forwarding traffic, not control plane functions. SXP (Security Group Tag Exchange Protocol) is incorrect because it's used to propagate Security Group Tags (SGTs), which are part of the security policy, not endpoint mapping.