.. _example_protocols_bgp_parameters_dampening: ######### Dampening ######### Scenario to verify BGP **dampening** parameter configuration. By default, BGP processes all route updates immediately, including routes that frequently change state. When a route repeatedly appears and disappears, it consumes CPU resources and can cause network instability. Route-flap dampening addresses this problem by assigning penalties to unstable routes. When a route flaps, its penalty increases, and once the penalty exceeds a threshold, the route is marked as damped with the ``d`` flag and is no longer advertised to peers, even though it remains visible in the BGP table. The ``dampening`` parameter requires four values that control the penalty system. The ``half-life`` determines how quickly penalties decay over time. The ``start-suppress-time`` sets the penalty threshold that triggers suppression. Once suppressed, a route remains damped until its penalty drops below ``re-use``. The ``max-suppress-time`` caps how long any route can be suppressed regardless of its penalty. In this test, **DUT0** (AS 100) establishes an eBGP session with **DUT1** (AS 200). The test configures aggressive dampening values to demonstrate the feature quickly. After simulating route flapping by repeatedly toggling redistribute connected, the route accumulates penalties and becomes suppressed, appearing with the ``d`` flag in the BGP table and in the dampening statistics. These aggressive values are optimized for testing; production environments typically use more conservative values to balance stability with responsiveness. ****************** Test BGP Dampening ****************** Description =========== This test verifies that route-flap dampening suppresses unstable routes by accumulating penalties. After configuring aggressive dampening values (1/1/1/1) on **DUT0**, the test simulates route flapping by repeatedly toggling redistribute connected on **DUT1**. The route quickly accumulates penalties and becomes suppressed, marked with the ``d`` (damped) flag in the BGP table. The test verifies the route appears in dampening statistics and is no longer advertised to peers until it stabilizes. Scenario ======== .. include:: dampening/testbgpdampening .. raw:: html