OSPF reduces routing updates by only sending updates when topology changes occur.

• A. It Sends Updates Only When There Is A Topology Change
• B. It Floods Updates Periodically Every Minute
• C. It Uses Constant Updates
• D. It Relies On BGP Metrics

Answer: (D)

OSPF is a link-state protocol that keeps a map of the network and uses the SPF algorithm to compute the best paths. Updates are produced and flooded only when there’s a topology change—like a link failing, a neighbor coming up, or a cost changing. This event-driven behavior means routers don’t send updates on a fixed schedule or at a constant rate; they react to changes and re-run the route calculation as needed. That’s why the scenario describes updates occurring only when topology changes happen.

The other ideas don’t fit because OSPF doesn’t flood updates periodically or continuously. It relies on its own per-link cost values to influence path selection, not external metrics from BGP, which is a different protocol used for routing between autonomous systems.