When vSmart is configured as a route reflector, which protocol carries routes between vSmart and WAN Edge routers?

The correct answer is OMP inside the DTLS/TLS control connection. The Overlay Management Protocol (OMP) is the routing protocol of Cisco SD-WAN, responsible for advertising routes, next-hop information, and security policies between vSmart controllers and WAN Edge routers. This communication occurs securely within the established DTLS (Datagram Transport Layer Security) or TLS (Transport Layer Security) control connections. IPsec inside the DTLS/TLS control connection is incorrect because IPsec is primarily used for data plane encryption between WAN Edge devices, not for control plane routing information. BGP inside the DTLS/TLS is incorrect because while BGP can be used in SD-WAN for specific scenarios (e.g., peering with external networks), OMP is the native and primary routing protocol between vSmart and WAN Edge routers. OMP outside the DTLS/TLS control connection is incorrect because all control plane communication in Cisco SD-WAN, including OMP, is secured and encapsulated within DTLS/TLS tunnels.