LAB: BGP Dampening w route-map

-  Ensure that dampening process applies only to AS 100 originated routes, and does not affect any other prefixes.

Sometimes it might be desirable to apply dampening only to a certain set of routes, e.g. to the prefixes originated from the “problematic” AS. Another good example might be a set of prefixes describing critical network resources that must always be available. To account for such situations it is possible to use a route map with the BGP dampening command to select prefixes eligible for dampening. The command 

bgp dampening route-map <MAP_NAME> 

where the route-map may match IP addresses using access-lists, prefix-lists and aspath lists. For every route-map entry you may set specific dampening parameters using the command set dampening

<Half_Life> <ReuseLimit><SuppressLimit> <MaximumSuppressTime>.

configuration:

R2, R3, R5, SW2, SW4:
ip as-path access-list 100 permit _100$
!
route-map DAMPENING
match as-path 100
set dampening 4 750 2000 16
!
router bgp 200
no bgp dampening
bgp dampening route-map DAMPENING

verification:

Rack1R3#show ip bgp dampening parameters
 dampening 4 750 2000 16 (route-map DAMPENING 10)
  Half-life time      : 4  mins       Decay Time       : 620 secs
  Max suppress penalty: 12000         Max suppress time: 16 mins
  Suppress penalty    :  2000         Reuse penalty    : 750

Rack1R3#show ip bgp dampening parameters
 dampening 4 750 2000 16 (route-map DAMPENING 10)
  Half-life time      : 4  mins       Decay Time       : 620 secs
  Max suppress penalty: 12000         Max suppress time: 16 mins
  Suppress penalty    :  2000         Reuse penalty    : 750