Route Flap Damping Commands

The route flap damping capability treats routes that are being announced and withdrawn (flapping) at a rapid rate as unreachable. If a route flaps at a low rate, it should not be suppressed at all, or suppressed for only a brief period of time. With route flap damping, the suppression of a route or routes occurs in a manner that adapts to the frequency and duration that a particular route appears to be flapping. The more a route flaps during a period of time, the longer it will be suppressed.

Each time a route flap occurs, a penalty of 100 is added to the route. When a route penalty exceeds the suppression threshold, the route is suppressed. The route penalty value decays over time. The half life of a route penalty is configurable for both reachable and unreachable routes. When the penalty falls below the reuse threshold, route dampening no longer suppresses the route. A hold-time value allows for the setting of a maximum time route dampening suppresses a route, regardless of its current route penalty. The amount of time a route flap is kept in memory is also configurable for both reachable and unreachable routes.