What is the OSPF cost of an Ethernet interface operating at 10 mbps with the default reference bandwidth?

To determine the OSPF cost of an Ethernet interface operating at 10 Mbps using the default reference bandwidth, it’s essential to understand how the OSPF cost is calculated.

OSPF (Open Shortest Path First) uses a cost metric to determine the best path for data. The cost is inversely proportional to the bandwidth of the interface. The formula used to calculate the OSPF cost for an interface is:

Cost = Reference Bandwidth / Interface Bandwidth

By default, Cisco routers use a reference bandwidth of 100 Mbps. Therefore, for an Ethernet interface with a bandwidth of 10 Mbps, the calculation is as follows:

Cost = 100,000 kbps / 10,000 kbps = 10

This means the OSPF cost for a 10 Mbps Ethernet interface, with the default reference bandwidth, is indeed 10. This calculation demonstrates how OSPF determines path selection, where lower costs indicate preferred paths.

Understanding this calculation is crucial, as it allows network professionals to effectively manage and optimize routing protocols for efficient network performance.