Which protocol is used for control connections between SD-WAN devices?

DTLS (Datagram Transport Layer Security) is the protocol used for establishing secure control plane connections between SD-WAN devices like vSmart controllers, vManage, and vBond orchestrators, as well as between vEdge routers and controllers. It provides authentication, encryption, and data integrity for the control traffic. BGP (Border Gateway Protocol) and OSPF (Open Shortest Path First) are routing protocols used for exchanging routing information within the data plane, not for control connections between SD-WAN components. OMP (Overlay Management Protocol) is a Cisco proprietary routing protocol that runs over DTLS connections to exchange routing, policy, and service information within the SD-WAN overlay, but DTLS is the underlying transport for OMP.