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PowerConnect B-Series FCX Configuration Guide 1009
53-1002266-01
Optional configuration tasks
30
To configure a route map, and use it to set or change route attributes for a network you define for
BGP4 to advertise, enter commands such as the following.
PowerConnect(config)#route-map set_net permit 1
PowerConnect(config-routemap set_net)#set community no-export
PowerConnect(config-routemap set_net)#exit
PowerConnect(config)#router bgp
PowerConnect(config-bgp-router)#network 100.100.1.0
/24 route-map set_net
The first two commands in this example create a route map named “set_net” that sets the
community attribute for routes that use the route map to “NO_EXPORT”. The next two commands
change the CLI to the BGP4 configuration level. The last command configures a network for
advertising from BGP4, and associates the “set_net” route map with the network. When BGP4
originates the 100.100.1.0/24 network, BGP4 also sets the community attribute for the network to
“NO_EXPORT”.
Syntax: network <ip-addr> <ip-mask> [route-map <map-name>] | [weight <num>] | [backdoor]
The route-map <map-name> parameter specifies the name of the route map you want to use to set
or change BGP4 attributes for the network you are advertising. The route map must already be
configured.
For information about the other parameters, refer to “Defining route maps” on page 1042.
Changing the default local preference
When the router uses the BGP4 algorithm to select a route to send to the IP route table, one of the
parameters the algorithm uses is the local preference. Local preference is an attribute that
indicates a degree of preference for a route relative to other routes. BGP4 neighbors can send the
local preference value as an attribute of a route in an UPDATE message.
Local preference applies only to routes within the local AS. BGP4 routers can exchange local
preference information with neighbors who also are in the local AS, but BGP4 routers do not
exchange local preference information with neighbors in remote autonomous systems.
The default local preference is 100. For routes learned from EBGP neighbors, the default local
preference is assigned to learned routes. For routes learned from IBGP neighbors, the local
preference value is not changed for the route.
When the BGP4 algorithm compares routes on the basis of local preferences, the route with the
higher local preference is chosen.
NOTE
To set the local preference for individual routes, use route maps. Refer to “Defining route maps” on
page 1042. Refer to “How BGP4 selects a path for a route” on page 983 for information about the
BGP4 algorithm.
To change the default local preference to 200, enter the following command.
PowerConnect(config-bgp-router)#default-local-preference 200
Syntax: default-local-preference <num>
The <num> parameter indicates the preference and can be a value from 0 through 4294967295.