Users Guide

Link dampening minimizes the risk created by flapping by imposing a penalty for each interface flap and decaying the penalty
exponentially. After the penalty exceeds a certain threshold, the interface is put in an Error-Disabled state and for all practical
purposes of routing, the interface is deemed to be “down.” After the interface becomes stable and the penalty decays below a
certain threshold, the interface comes up again and the routing protocols re-converge.
Link dampening:
• reduces processing on the CPUs by reducing excessive interface flapping.
• improves network stability by penalizing misbehaving interfaces and redirecting traffic.
• improves convergence times and stability throughout the network by isolating failures so that disturbances are not
propagated.
Important Points to Remember
• Link dampening is not supported on VLAN interfaces.
• Link dampening is disabled when the interface is configured for port monitoring.
• You can apply link dampening to Layer 2 and Layer 3 interfaces.
• You can configure link dampening on individual interfaces in a LAG.
Enabling Link Dampening
To enable link dampening, use the following command.
• Enable link dampening.
INTERFACE mode
dampening
Examples of the show interfaces dampening Commands
To view the link dampening configuration on an interface, use the show config command.
R1(conf-if-te-1/1)#show config
!
interface TenGigabitEthernet 1/1
ip address 10.10.19.1/24
dampening 1 2 3 4
no shutdown
To view dampening information on all or specific dampened interfaces, use the show interfaces dampening command
from EXEC Privilege mode.
Dell#show interfaces dampening
Interface Supp Flaps Penalty Half-Life Reuse Suppress Max-Sup
State
Te 1/1 Up 0 0 1 2 3 4
Te 1/2 Up 0 0 1 2 3 4
Te 1/2 Up 0 0 1 2 3 4
Dell#
To view a dampening summary for the entire system, use the show interfaces dampening summary command from EXEC
Privilege mode.
Dell# show interfaces dampening summary
20 interfaces are configured with dampening. 3 interfaces are currently suppressed.
Following interfaces are currently suppressed:
Te 1/2
Te 3/1
Te 4/2
Dell#
Interfaces 399