System information

Configuring BGP
12-19
Example
The commands in the following example show four configured route-reflector-clients
for a router acting as a route reflector (as shown in Figure 12-8). The no bgp
client-to-client reflection command disables client-to-client reflection because the
clients are fully meshed.
MOT(config)#router bgp 100
MOT(config-bgp)#neighbor 140.20.10.2 route-reflector-client
MOT(config-bgp)#neighbor 140.20.10.3 route-reflector-client
MOT(config-bgp)#neighbor 140.20.10.4 route-reflector-client
MOT(config-bgp)#neighbor 140.20.10.5 route-reflector-client
MOT(config-bgp)#no bgp client-to-client reflection
Configuring Route Flap Dampening
The BSR supports two types of route flap dampening.
• Global
• Policy-based
Route flapping occurs when a link constantly fluctuates between being available and
unavailable. When a link changes its availability, the upstream neighbor sends an
update message to all its neighbors. These routes are advertised globally. This process
continues until the underlying problem is fixed.
Route flap dampening is a mechanism for minimizing instability caused by route
flapping. A penalty value for a route is increased by 1000 if the route flaps and is
decreased by half after 15 minutes. Once the penalty exceeds the suppress limit of
2000, the route is no longer advertised to neighbors. (The route is damped.) When the
penalty for a damped route falls below the reuse limit of 750, the route is again
available.
Global Route Flap Dampening
1. To enable global route flap dampening with default values on all BGP routes, use
the bgp dampening command in Router BGP Configuration mode, as shown
below:
MOT(config-bgp)#bgp dampening