Underlay via public connection such as the internet corresponds to which UCS type?

• A. Private UCS
• B. Flat Rate UCS
• C. Non Shared Underlay Transport
• D. Public UCS

Answer: (D)

Underlay connectivity in SD-WAN refers to the actual transport network that carries the overlay traffic. When that underlay runs over a public network like the Internet, it is categorized as Public UCS. This reflects the shared, public nature of the transport rather than a private, dedicated path.

Public UCS is chosen because the Internet is a common, non-dedicated medium used by many customers, unlike Private UCS, which would imply a dedicated private link (such as MPLS or dedicated fiber). Non Shared Underlay Transport would suggest a dedicated path not shared with others, which doesn’t align with using the public Internet. Flat Rate UCS describes a pricing model, not the type of underlay network.