Setting the Interface Cost

You can adjust and optimize route selection by setting the OSPF interface cost.

Context

After the OSPF interface costs are set, the interface with a smaller cost value preferentially transmits routing information. This helps select the optimal route.

The OSPF interface cost can be set or calculated based on the interface bandwidth.

External factors may affect the physical bandwidth of links and change the physical bandwidth of interfaces, which in turn affects network performance. To address this problem, you can run the bandwidth bandwidth command in the interface view to set configuration bandwidth for the interface, and then run the bandwidth-config enable command to enable the device to calculate the cost for the OSPF interface based on the configuration bandwidth of the interface.

Procedure

Manually configure a cost for an OSPF interface.
1. Run system-view
  The system view is displayed.
2. Run interface interface-type interface-number
  The interface view is displayed.
3. Run ospf cost value
  A cost is set for the interface.
4. Run commit
  The configuration is committed.
Configure bandwidth-based automatic OSPF interface cost calculation.
The calculation formula is as follows: Interface cost = Bandwidth reference value/Interface bandwidth. The integer of the calculation result is used as the cost of the interface. If the result is less than 1, the cost is 1.
Perform the following operations as required:
- To use the bandwidth reference value to determine the interface cost, run the bandwidth-reference command.
- To use the interface bandwidth to determine the interface cost, run the bandwidth command to set configuration bandwidth for an interface, and then run the bandwidth-config enable command to enable the device to calculate the cost for the OSPF interface based on the configuration bandwidth of the interface.
- To use both the bandwidth reference value and interface bandwidth to determine the interface cost, run the preceding three commands.
1. Run system-view
  The system view is displayed.
2. Run interface interface-type interface-number
  The interface view is displayed.
3. Run bandwidth bandwidth
  Configuration bandwidth is set for the interface.
4. Run quit
  Exit the interface view.
5. Run ospf [ process-id ]
  The OSPF view is displayed.
6. Run bandwidth-reference value
  A bandwidth reference value is set.
7. Run bandwidth-config enable
  The configuration bandwidth of each OSPF interface is allowed to participate in cost calculation for the interface.
  - If the bandwidth command is not run, the cost is calculated based on the physical bandwidth of each OSPF interface.
  - If the bandwidth-config enable command is not run, the cost is calculated based on the physical bandwidth of each OSPF interface.
8. Run commit
  The configuration is committed.