How does BGP handle route flapping in large networks?

Ask any question about Networking here... and get an instant response.

Post this Question & Answer:

How does BGP handle route flapping in large networks?

Asked on Dec 14, 2025

Answer

BGP handles route flapping in large networks using a mechanism called route dampening, which aims to stabilize the network by suppressing routes that change state too frequently. This helps prevent excessive CPU and memory usage on routers due to constant updates.

Example Concept: BGP route dampening assigns a penalty to routes each time they flap (go up and down). When the penalty exceeds a predefined "suppress limit," the route is suppressed and not advertised. Over time, the penalty decays, and once it falls below a "reuse limit," the route can be advertised again. This mechanism helps maintain network stability by reducing the impact of unstable routes.

Additional Comment:

Route dampening is configurable on routers running Cisco IOS, Juniper Junos, and other BGP-capable platforms.
The parameters for route dampening include half-life, reuse limit, suppress limit, and maximum suppress time.
Careful tuning of these parameters is essential to balance between stability and convergence time.
Route dampening is not recommended for all BGP environments, especially where route stability is critical.

✅ Answered with Networking best practices.

Ask any question about Networking here... and get an instant response.