Task 1
Remove configuration from the previous lab.
Task 2
You will need to prepare for the migration towards 10Gbps. As a test, you have been asked to change the metric on R6 so that a 100Mbps link should have a metric of 100 instead of 1 (default).
Task 3
If the result of the configuration is satisfactory, restore the default cost calculation on R6.
Questions
Task 2
You will need to prepare for the migration towards 10Gbps. As a test, you have been asked to change the metric on R6 so that a 100Mbps link should have a metric of 100 instead of 1 (default).
Task 3
If the result of the configuration is satisfactory, restore the default cost calculation on R6.
- What are the options to change OSPF metric in an consistent manner?
Lab Solution
Solution configuration can be accessed below; solution contains task 1 and task 2 (if you want to save it, click the link, then go to File-->Download):
https://drive.google.com/file/d/0BwE5C95tpjZOM3NWTTA5UktFdW8/edit?usp=sharing
Task 1
Remove configuration from the previous lab.
R1 Config:
!
router ospf 1
no neighbor 172.16.0.4 cost 100
!
Task 2
You will need to prepare for the migration towards 10Gbps. As a test, you have been asked to change the metric on R6 so that a 100Mbps link should have a metric of 100 instead of 1 (default).
R6 Config:
!
router ospf 1
auto-cost reference-bandwidth 10000
!
Note!
As soon as you change the default auto-cost reference-bandwidth, you get the warning as shown below. The same configuration should be applied on all routers in the OSPF domain. In our case it is just a quick test, so we will revert this back to the default value.
Task 3
If the result of the configuration is satisfactory, restore the default cost calculation on R6.
R6 Config:
!
router ospf 1
no auto-cost reference-bandwidth 10000
!
R1 Config:
!
router ospf 1
no neighbor 172.16.0.4 cost 100
!
Task 2
You will need to prepare for the migration towards 10Gbps. As a test, you have been asked to change the metric on R6 so that a 100Mbps link should have a metric of 100 instead of 1 (default).
R6 Config:
!
router ospf 1
auto-cost reference-bandwidth 10000
!
Note!
As soon as you change the default auto-cost reference-bandwidth, you get the warning as shown below. The same configuration should be applied on all routers in the OSPF domain. In our case it is just a quick test, so we will revert this back to the default value.
Pic. 2 - Warning.
Pic. 3 - New Metric on R6.
If the result of the configuration is satisfactory, restore the default cost calculation on R6.
R6 Config:
!
router ospf 1
no auto-cost reference-bandwidth 10000
!
Pic. 4 - Metric on R6 Restored.
Study Drill
If a network designer wants to apply consistent metric in Cisco OSPF domain, there are two common solutions in use. In the first one, a consistent bandwidth-to-cost conversion table can be created similar to the one STP uses. Then, the designer can use 'ip ospf cost' command throughout the domain to manually apply the costs on every interface. Alternatively, every router can have the value of auto-cost reference-bandwidth changed using the new value (default = 100, representing 100Mbps).