CCNA Drill: Underlay vs Overlay in 20 seconds
Do you know the difference between underlay and overlay? Drop your answer in the comments before the timer runs out!
The question
In Cisco SD-Access, what term describes the physical infrastructure providing underlying IP reachability?
The answer
A Underlay
The underlay is just your physical routers, switches, and baseline routing providing raw transport. Don't confuse it with the overlay, which is the virtual tunnel network riding on top. Follow for tomorrow's rep.
Exam tip
Read what the question is actually asking before looking at the options. The wrong answers here are ones candidates genuinely pick — each is true of something adjacent, just not of what was asked.