How does OSPF measure the metric of a network?

• A. Cisco's Cost-Based Cumulative Bandwidth From Source To Destination
• B. Hop Count
• C. Delay
• D. Bandwidth

Answer: (A)

OSPF uses a metric called cost, which is tied to the bandwidth of each link. Each interface is assigned a cost based on its speed (in most implementations cost = reference bandwidth / interface bandwidth). The total cost to reach a destination is the sum of the costs of all the links along the path, so the router chooses the path with the smallest total cost. This is why a cost-based, cumulative measure of bandwidth best describes how OSPF evaluates routes. It’s not simply hop count or delay, and it’s not the raw bandwidth itself—the cost reflects bandwidth in a way that favors higher-speed paths while summing across the route.