BGP and Dampened Routes

The switch supports route dampening (route suppression). When you use route dampening, a route accumulates penalties each time the route fails. After the accumulated penalties exceed a threshold, the router no longer advertises the route. The router enters the suppressed routes into the routing table only after the accumulated penalty falls below the reuse threshold.

Route flap dampening suppresses the advertisement of the unstable route until the route becomes stable. For information about how to enable flap-dampening, see Configure BGP. For information about viewing flap dampening configurations, see View Global Flap-Dampening Configurations.

Dampening applies only to routes that are learned through an eBGP. Route flap dampening prevents routing loops and protects iBGP peers from having higher penalties for routes external to the AS.

The following paragraph describes the algorithm that controls route flaps.

After the route flaps the first time

After the route flaps a second time