What is a stub network in routing terms?

• A. A network with only a single exit path, typically requiring a default route to reach elsewhere.
• B. A network with no routes learned.
• C. A network that uses only static routes.
• D. A network that can only be reached via BGP.

Answer: (A)

A stub network is a network that has only one exit point to reach destinations outside its own network. Because there’s a single path out, the router at the edge usually uses a default route (a catch-all route) to forward traffic for any destinations not in its local network. This simplifies routing and reduces the amount of detailed external reachability the router must maintain. It’s not about having no routes, nor about requiring static routes or being tied to a specific protocol like BGP—the key idea is the single exit path that makes a default route practical.