BGP why route dampening is obsolete
BGP route dampening is a feature that is considered obsolete for today's networks. It is considered best practice not to employ it.
BGP route dampening can be used to prevent installing flapping BGP routes and forwarding them to other BGP routers. This decreases the CPU load of routers and increases network stability. Nowadays, routers are powerful enough to process BGP updates so dampening isn’t considered a best practice anymore. Back in the 90s, routers weren’t so powerful.
BGP dampening introduces some unwanted phenomena in BGP. RIPE NCC, or Réseaux IP Européens Network Coordination Centre is the regional internet registry for Europe, the Middle East, and parts of Asia. They’ve issued a Working Group Recommendation concerning dampening which shows that BGP dampening introduces impeded convergence and incompatible minimum route advertisement interval on networks managed by different ISPs.
In the past, overwhelming the CPU resources of a BGP router due to flapping BGP routes was worse than the network problems introduced by the feature. Today, however, it is preferable to just let BGP routes flap, rather than dampen them.