Controlling the Cost of Individual Network Segments

When evaluating the cost of individual network segments, OSPF evaluates the reference bandwidth. For any link faster than 100 Mbps, the default cost metric is 1. When OSPF calculates the SPF algorithm, it sums the metrics of all interfaces along a path to determine the overall cost of the path. The path with the lowest metric is selected for the forwarding table.

To control the cost of the network segment, you can modify the metric value on an individual interface. Suppose all routers in the OSPF network use default metric values. If you increase the metric on an interface to 5, all paths through this interface have a calculated metric higher than the default and are not preferred.

To manually set the cost of a network segment on the stub area's Fast Ethernet interface by modifying the interface metric:

1. Navigate to the top of the configuration hierarchy in either the J-Web or the CLI configuration editor.
2. Perform the configuration tasks described in Table 132.

Table 132: Controlling the Cost of Individual Network Segments by Modifying the Metric