ECS4660-28F_Management Guide-R03

C HAPTER 51 | IP Routing Commands
Border Gateway Protocol (BGPv4)
– 1844 –
EXAMPLE
This example divides AS 600 into four smaller ASes 101-104, and assigns a
neighboring router as a member of the sub-AS 101.
Console(config-router)#bgp confederation identifier 600
Console(config-router)#bgp confederation peer 101
Console(config-router)#bgp confederation peer 102
Console(config-router)#bgp confederation peer 103
Console(config-router)#bgp confederation peer 104
Console(config-router)#neighbor 192.168.0.9 remote-as 101
Console(config-router)#
RELATED COMMANDS
bgp confederation identifier (1842)
bgp dampening This command configures route dampening to reduce the propagation of
unstable routes. Use the no form to restore the default settings.
SYNTAX
bgp dampening [half-life [reuse-limit [suppress-limit
max-suppress-time]]]
no dampening
half-life – The time after which a penalty is reduced. The penalty
value is reduced to half of the previous value after the half-life time
expires. (Range: 1-45 minutes)
reuse-limit – The point at which the penalty for a flapping route
must fall before a route is unsuppressed. (Range: 1-2000)
suppress-limit – The point at which to start suppressing a route.
(Range: 1-2000)
max-suppress-time – The maximum time a route can be
suppressed. (Range: 1-255 minutes)
COMMAND MODE
Router Configuration
DEFAULT SETTING
half-life: 15 minutes
reuse-limit: 750
suppress-limit: 2000
max-suppress-time: 60 minutes (4 x half-life)
COMMAND USAGE
◆ Route dampening is used to reduce the frequency of routing updates
due to unstable routes. Dampened routes are not used in the BGP
decision process nor installed in the routing table.
◆ Each time a route flaps, the router assigns the route a penalty of 1000.
If BGP receives an attribute change, BGP increases the penalty by 500.