The apply dampening command sets dampening parameters for EBGP routes.
The undo apply dampening command cancels the configuration.
By default, no dampening parameters are set for EBGP routes.
| Parameter | Description | Value |
|---|---|---|
| half-life-reach | Specifies the half-life of a reachable route. | The value is an integer ranging from 1 to 45, in minutes. |
| reuse | Specifies the threshold for routes to be released from the dampening state. When the penalty value falls below the threshold, routes are reused. | The value is an integer ranging from 1 to 20000. |
| suppress | Specifies the threshold for routes to enter the dampening state. When the penalty value exceeds the threshold, routes are suppressed. | The value is an integer ranging from 1 to 20000. The configured value of suppress must be much greater than the value of reuse. |
| ceiling | Specifies the upper limit of the penalty value of routes. | The value is an integer ranging from 1001 to 20000. The configured value of ceiling must be greater than the value of suppress. |
Usage Scenario
The apply dampening command, which is mostly used in BGP, is used to prevent frequent route dampening from affecting routers on the network.
You can configure different route dampening parameters for different nodes in the same route-policy. When route flapping occurs, BGP can use different route dampening parameters to suppress the routes that match the route-policy.
Procedure
If the apply dampening command is run more than once, the latest configuration overwrites the previous one.
Configuration Impact
If the apply dampening command is run, each time route flapping occurs, BGP adds a certain penalty value to this route.
Precautions
The parameters in this command do not have default values and therefore must be set. The values of reuse, suppress, and ceiling are listed in ascending order: reuse < suppress <ceiling. According to the formula, MaxSuppressTime = half-life-reach x 60 x (ln (ceiling/reuse)/ln (2)), routes are unsuppressed if the value of MaxSuppressTime is less than 1. Therefore, the value of the ceiling/reuse must be great enough so that the value of MaxSuppressTime can be equal to or greater than 1.