Advanced BGP Features: Route Dampening

When you check the BGP prefixes using the "show ip bgp", besides the arguments that appeared so far (*, >, r) there
is another "Tag" that can appear, and it's a letter "d", which stends for DAMPENING.
#show ip bgp
BGP table version is 5, local router ID is 192.168.2.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal <- CHECK THIS LINE
              r RIB-failure, S Stale

From Cisco Docs: "Route dampening is a BGP feature designed to minimize the propagation of flapping routes across
an internetwork. A route is considered to be flapping when its availability alternates repeatedly"

If you're configuring it without any parameter tuning, there is an enable command under the BGP process:
(config-router)#bgp dampening

If you want to use this feature - make sure you understand the concept of PENALTIES being "rewarded" to a route
every time it FLAPS, and make sure you're familiar with the PARAMETERS of BGP DAMPENING:
#sh ip bgp dampening parameters
 dampening 15 750 2000 60 (DEFAULT)
  Half-life time      : 15 mins       Decay Time       : 2320 secs
  Max suppress penalty: 12000         Max suppress time: 60 mins
  Suppress penalty    :  2000         Reuse penalty    : 750
 
1. HALF-TIME (default 15 minutes)
When the penalty is assigned to a route, the accumulated penalty is decreased every 5 seconds. When the half-time
expires, accumulated penalties are reduced by half.  Default HALF-TIME is 15 minutes, and range 1-45 minutes.

2. REUSE (default 750)
The route can be REUSABLE if the penalties for flapping route go BELOW THIS VALUE. By default it's 750,
and the range is 1 to 20000

3. SUPRESS
The route is SUPRESSED when the penalties REACH THIS VALUE. Default is 2000, and the range is 1-20000

4. MAX-SUPRESS-TIME
Max time that the route can STAY SUPRESSED. Default is 4 times Half-Time value (60 minutes), range is 1-255

If you need to configure the BGP DAMPENING for a certain routes, use the ROUTE-MAP:
(config-router)#route-map DAMPEN_1
(config-route-map)#match ip add 15 <- CONFIGURE THE ROUTES YOU ARE DAMPENING IN AN ACL
(config-route-map)#set dampening 15 700 2000 60 <- SET DESIRED DAMPENING PARAMETERS

Then apply it within the BGP configuration process:
(config-router)#bgp dampening route-map DAMPEN_1

!!!This configuration can get quite complicated, so you might need to MATCH THE AS-PATH,
for this you need to be quite comfortable with META CHARACTERS, so for example match prefixes originated in AS 300:
(config)#ip as-path access-list 15 permit ^300$

And then MATCH it in the route-map and SET the dampening parameters:
(config-router)#route-map DAMPEN_2
(config-route-map)#match as-path 15
(config-route-map)#set dampening 15 700 2000 60