Users Guide

0 4 SFP 10GBASE-SX APF12420031B3P
0 5 SFP 10GBASE-SX APF12420031B3P
0 6 SFP 10GBASE-SX APF12420031B3P
0 7 SFP 10GBASE-SX APF12420031B3P
0 8 QSFP 4x10GBASE-CR1-3M APF12420031B3P
0 9 QSFP 4x10GBASE-CR1-3M APF12420031B3P
0 10 QSFP 4x10GBASE-CR1-3M APF12420031B3P
0 11 QSFP 4x10GBASE-CR1-3M APF12420031B3P
0 12 QSFP 40GBASE-SR4
Link Dampening
Interface state changes occur when interfaces are administratively brought up or down or if an interface state changes.
Every time an interface changes a state or aps, routing protocols are notied of the status of the routes that are aected by the
change in state. These protocols go through the momentous task of re-converging. Flapping; therefore, puts the status of entire
network at risk of transient loops and black holes.
Link dampening minimizes the risk created by apping by imposing a penalty for each interface ap 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 apping.
• improves network stability by penalizing misbehaving interfaces and redirecting trac.
• 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 congured for port monitoring.
• You can apply link dampening to Layer 2 and Layer 3 interfaces.
• You can congure 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 conguration 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 specic dampened interfaces, use the show interfaces dampening command from
EXEC Privilege mode.
Dell# show interfaces dampening
InterfaceStateFlapsPenaltyHalf-LifeReuseSuppressMax-Sup
Te 1/1Up005750250020
390
Interfaces