Which protocol enables WAN Edge devices to learn remote sites and establish overlay tunnels?

• A. BFD
• B. SLAAC
• C. CAPWAP
• D. Overlay Management Protocol (OMP)

Answer: (D)

The capability to learn remote sites and automatically set up overlay tunnels is driven by the overlay management/control plane used in SD-WAN. This protocol distributes reachability information, site metadata, and policy between WAN Edge devices, so each edge knows about other sites and which VPNs or overlays to use. With this information, the edges can establish the appropriate overlay tunnels (such as IPsec tunnels) and steer traffic across the unified network according to the defined policies.

Other protocols don’t provide this combination of site discovery and overlay tunnel provisioning: a fast-fail detection protocol checks connectivity quickly but doesn’t learn sites or build tunnels; an IPv6 address autoconfiguration protocol assigns addresses but doesn’t manage overlay topology; a wireless AP management protocol handles access points, not WAN-edge site learning or overlay tunnels.