Lab 23 - OSPF Changing Auto-Cost Reference-Bandwidth

Prerequisites: CCNP level skills.

Note!
Use OSPF point-to-multipoint on the Frame-Relay connections (configuration and topology from Lab20).

Topology

Pic. 1 - OSPF Topology.

Icons designed by: Andrzej Szoblik - http://www.newo.pl

Task 1

In order to support 1 Gbps interfaces, change the way OSPF calculates the cost. The cost of FastEthernet interface should be 500.

Lab Solution

Task 1
In order to support 1 Gbps interfaces, change the way OSPF calculates the cost. The cost of FastEthernet interface should be 500.

Note!

The default OSPF reference bandwidth used to calculate the cost of the interface is 100Mbps (number=100). The formula is:

cost = Reference-Bandwidth / Bandwidth_of_the_link

Note!

After changing the reference-bandwidth on one router, this same way should be used on all of them in order to have a consistent way of calculating the cost.

R1, R2, R3 Configuration:

!

router ospf 1
 auto-cost reference-bandwidth 50000

!

Verification:

Pic. 2 - R2's Cost of F1/0.