What does 'OSPF cost' determine in the protocol's metric?

In OSPF (Open Shortest Path First), the OSPF cost primarily represents the inverse of the bandwidth of the link. It is calculated based on the link's bandwidth, with higher bandwidth links receiving a lower cost value, thus making them more favorable for routing decisions.

The cost metric helps OSPF determine the best path to a destination based on link speed rather than distance in terms of hop count. When OSPF assesses multiple routes to a destination, it will choose the route with the lowest cost, which corresponds to the highest bandwidth link available.

While it may seem that the choice regarding the overhead of using a particular route could relate to the OSPF cost, this is not the case as the cost is specifically tied to the bandwidth rather than overhead related to the protocol’s operation. Cost in OSPF does not quantify distance in terms of hops or reliability; instead, it focuses directly on the capacity of the communication links. Thus, it is essential to understand that OSPF cost acts as a measure of the effective bandwidth for routing decisions.