The bandwidth-reference command sets the bandwidth reference value that is used in automatic IS-IS interface cost calculation.
The undo bandwidth-reference command restores the default bandwidth reference value that is used in automatic IS-IS interface cost calculation.
By default, the bandwidth reference value is 100 Mbit/s.
| Parameter | Description | Value |
|---|---|---|
value |
Specifies the bandwidth reference value used in automatic IS-IS interface cost calculation. |
The value is an integer that ranges from 1 to 2147483648, in Mbit/s. |
Usage Scenario
To make the set link cost of IS-IS routes reflect the actual link cost, configure a proper link cost for all interfaces or enable automatic interface cost calculation. To enable automatic interface cost calculation, set a proper bandwidth reference value.
You can run the bandwidth-reference command to set a proper bandwidth reference value. After automatic interface cost calculation is enabled, and the cost type is wide or wide-compatible, the system calculates the cost of each interface with the following formula: Interface cost = (Bandwidth-reference/Interface bandwidth) x 10. If the interface cost calculated through this formula is greater than 16777214, 16777214 is used as the interface cost for route calculation. That is, the interface cost will never be greater than 16777214.
The bandwidth bandwidth command can only set an interface bandwidth obtained by the NMS from the MIB. It cannot change an interface actual bandwidth and interface cost.
After the auto-cost enable command enables automatic IS-IS interface cost calculation, the system automatically calculates the interface cost based on the bandwidth reference value set using the bandwidth-reference 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.
Precautions
The bandwidth reference value set using the bandwidth-reference command takes effect only when the cost style is wide or wide-compatible. In this case, the interface cost is calculated using the following formula:
Interface cost = (Bandwidth-reference/Interface bandwidth) × 10.
If the cost style of the system is narrow, narrow-compatible or compatible, the cost of each interface is based on the following table.
Cost |
Range of the Interface Bandwidth |
|---|---|
60 |
Interface bandwidth =< 10 Mbit/s |
50 |
10 Mbit/s < Interface bandwidth =< 100 Mbit/s |
40 |
100 Mbit/s < Interface bandwidth =< 155 Mbit/s |
30 |
155 Mbit/s < Interface bandwidth =< 622 Mbit/s |
20 |
622 Mbit/s < Interface bandwidth =< 2.5 Gbit/s |
10 |
2.5 Gbit/s < Interface bandwidth |