Configuring Flap Damping for BGP Routes
BGP route flapping describes the situation in which BGP systems send an excessive number of update messages to advertise network reachability information. BGP flap damping is a method of reducing the number of update messages sent between BGP peers, thereby reducing the load on these peers, without adversely affecting the route convergence time for stable routes.
By default, route flap damping is disabled. To enable it, include the damping statement:
For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.
Damping is applied to external peers and to peers at confederation boundaries. For finer control over which peers have damping enabled, include the damping statement at the [edit protocols bgp group group-name] hierarchy level.
By default, route flap damping uses the following parameters:
- Decay half-life while reachable—15 minutes
- Maximum hold-down time—60 minutes
- Reuse threshold—750
- Cutoff threshold—3000
To change these default parameters, you must define the flap damping parameters by including the damping statement at the [edit policy-options] hierarchy level and then apply them by including an import statement when configuring BGP. For more information about flap damping and defining flap damping parameters, see the Junos Policy Framework Configuration Guide. For more information about applying policy filters in BGP, see Applying Policies to BGP Routes.
