What does OSPF use to maintain an up-to-date routing table?

• A. Each OSPF router collects link-state information to construct a database representing the network topology
• B. Periodic exchange of distance vectors
• C. Static routes configured by the administrator
• D. A central controller distributing routes

Answer: (A)

OSPF keeps its routing table current by using a link-state approach. Each router learns the status of its own links and then floods that link-state information to every other router in the area, creating a common, complete view of the network topology. With this shared database, each router runs the shortest-path-first algorithm to compute the best paths and update its routing table. When a link or topology changes, the new information is propagated and the SPF calculation runs again to refresh the routes.

This differs from periodic distance-vector updates (typical of protocols like RIP), which recalculates routes based on hop counts exchanged periodically. Static routes are fixed and don’t adapt to topology changes, and a central controller distributing routes describes a software-defined networking approach, not OSPF’s distributed model.