The bandwidth-reference command sets the bandwidth reference value that is used to calculate interface costs.
The undo bandwidth-reference command restores the default bandwidth reference value.
The default bandwidth reference value is 100 Mbit/s.
| Parameter | Description | Value |
|---|---|---|
| value | Specifies the bandwidth reference value for link cost calculation. | The value is an integer ranging from 1 to 2147483648, in Mbit/s. The default value is 100Mbit/s. |
Usage Scenario
The calculation formula is as follows: Interface cost = Bandwidth reference value/Interface bandwidth. The integer of the calculated result is the interface cost. If the calculated result is smaller than 1, the interface cost value is 1. If the bandwidth-reference command is executed to configure a new bandwidth reference value, the interface cost will be changed. As a result, OSPF will re-select routes.
The default bandwidth reference value is 100 Mbit/s. The interface cost value is 100000000 divided by the interface bandwidth value.
With the formula 100000000/Bandwidth, the default costs of various types of interfaces are as follows:
56 kbit/s Serial port: 1785
64 kbit/s Serial port: 1562
E1 (2.048 Mbit/s): 48
Ethernet (100 Mbit/s): 1
Configuration Impact
After the bandwidth-reference command is configured in a process view, bandwidth reference values of all interfaces in the process are changed to the specified value.
Precautions
Generally, OSPF automatically calculate the link cost for an interface based on the bandwidth of the interface. You can modify the interface cost using the ospf cost command.
The bandwidth-reference command can be operated on Eth-Trunk interfaces as same with on physical interfaces. If the command is run on an Eth-Trunk interface, the bandwidth of the Eth-Trunk interface is equal to the total bandwidth of all its member interfaces.