What is the default OSPF cost for any link with a bandwidth of 100 Mb/s or greater?

In OSPF (Open Shortest Path First), the cost of a link is inversely related to its bandwidth. The formula used to calculate the OSPF cost is:

Cost = Reference Bandwidth / Interface Bandwidth

The default reference bandwidth in OSPF is typically set to 100 Mbps, although it can be modified if needed. For any link with a bandwidth of 100 Mb/s or greater, the cost would be calculated as follows:

Cost = 100,000 kbps / 100,000 kbps = 1

This means that any link running at 100 Mbps or faster will have a default OSPF cost of 1. This value is essential for OSPF to determine the most efficient path through the network based on link costs. A lower cost indicates a more preferred route. Higher bandwidth links contribute to lower costs, making them more favorable during the OSPF route selection process.

Understanding this cost calculation is crucial for network engineers and administrators when designing and troubleshooting OSPF-configured networks, ensuring optimal routing decisions are made for data flow.