Brocade BigIron RX Series Configuration Guide - Manual (Page 918)

840 BigIron RX Series Configuration Guide
53-1002484-04
Configuring route flap dampening
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Syntax: confederation peers <num> [<num> …]
The <num> parameter with the confederation peers command indicates the sub-AS numbers for
the sub-ASs in the confederation. You may list all sub-ASs in the confederation. Also, you must
specify all the sub-ASs with which this router has peer sessions in the confederation. All the
routers within the same sub-AS use IBGP to exchange router information. Routers in different
sub-ASs within the confederation use EBGP to exchange router information. You can specify a
number from 1 – 65535.
Commands for Router B
BigIron RXB(config)# router bgp
BigIron RXB(config-bgp)# local-as 64512
BigIron RXB(config-bgp)# confederation identifier 10
BigIron RXB(config-bgp)# confederation peers 64512 64513
BigIron RXB(config-bgp)# write memory
Commands for Router C
BigIron RXC(config)# router bgp
BigIron RXC(config-bgp)# local-as 64513
BigIron RXC(config-bgp)# confederation identifier 10
BigIron RXC(config-bgp)# confederation peers 64512 64513
BigIron RXC(config-bgp)# write memory
Commands for Router D
BigIron RXD(config)# router bgp
BigIron RXD(config-bgp)# local-as 64513
BigIron RXD(config-bgp)# confederation identifier 10
BigIron RXD(config-bgp)# confederation peers 64512 64513
BigIron RXD(config-bgp)# write memory
Configuring route flap dampening
Route Flap Dampening reduces the amount of change propagated by BGP due to routing state
caused by unstable routes. Reducing change propagation will help reduce processing
requirements.
To enable route flap dampening using the default values, enter the following command.
BigIron RX(config-bgp)# dampening
Syntax: dampening [<half-life> <reuse> <suppress> <max-suppress-time>]
The <half-life> parameter specifies the number of minutes after which the route’s penalty becomes
half its value. The route penalty allows routes that have remained stable for a while despite earlier
instability to eventually become eligible for use again. The decay rate of the penalty is proportional
to the value of the penalty. After the half-life expires, the penalty decays to half its value. Thus, a
dampened route that is no longer unstable can eventually become eligible for use again. You can
configure the half-life to be from 1 - 45 minutes. The default is 15 minutes.
The <reuse> parameter specifies how low a route’s penalty must become before the route
becomes eligible for use again after being suppressed. You can set the reuse threshold to a value
from 1 – 20000. The default is 750 (0.75, or three-fourths, of the penalty assessed for a one
“flap”).