Final answer:
The OSPF path cost from RouterA to RouterC, which goes through RouterB, is 11, as it adds individual default costs of 1 for FastEthernet and 10 for Ethernet.
Step-by-step explanation:
The question asks about the OSPF path cost from RouterA to RouterC. In OSPF, the default cost value for a FastEthernet link (100 Mbps) is 1, and the default cost value for an Ethernet link (10 Mbps) is 10. Since the path from RouterA to RouterC goes through both a FastEthernet and an Ethernet connection, the total cost would be the sum of the individual costs of these links.
Therefore, the OSPF cost from RouterA to RouterB (FastEthernet link) is 1, and from RouterB to RouterC (Ethernet link) is 10. When you sum these costs, you get a total OSPF path cost of 11.
In OSPF, the cost of a path is determined based on the bandwidth of the link. The default formula to calculate the cost is inversely proportional to the bandwidth. Specifically, the cost is computed as Cost = Reference Bandwidth / Interface Bandwidth.
The default reference bandwidth in OSPF is 10^8 bps (bits per second). For FastEthernet, which typically has a bandwidth of 100 Mbps, the cost would be 10^8 / 10^8 = 1. For Ethernet, which usually has a bandwidth of 10 Mbps, the cost would be 10^8 / 10^7 = 10.
Therefore, the OSPF cost for the FastEthernet link between RouterA and RouterB will likely be 1, and for the Ethernet link between RouterB and RouterC, it will likely be 10. When calculating the total cost from RouterA to RouterC, OSPF sums up the individual link costs, resulting in a most likely total cost of 1 + 10 = 11 for the path from RouterA to RouterC.