Brocade TurboIron 24X Series Configuration Guide - Manual (Page 721)

Brocade TurboIron 24X Series Configuration Guide 687
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Optional configuration tasks
Using the IP default route as a valid next hop for
a BGP4 route
By default, the Layer 3 Switch does not use a default route to resolve a BGP4 next-hop route. If the
IP route lookup for the BGP4 next hop does not result in a valid IGP route (including static or direct
routes), the BGP4 next hop is considered to be unreachable and the BGP4 route is not used.
In some cases, such as when the Layer 3 Switch is acting as an edge router, you might want to
allow the device to use the default route as a valid next hop. To do so, enter the following command
at the BGP4 configuration level of the CLI.
TurboIron(config-bgp-router)#next-hop-enable-default
Syntax: [no] next-hop-enable-default
Advertising the default route
By default, the Layer 3 Switch does not originate and advertise a default route using BGP4. A BGP4
default route is the IP address 0.0.0.0 and the route prefix 0 or network mask 0.0.0.0. For example,
0.0.0.0/0 is a default route. You can enable the router to advertise a default BGP4 route using
either of the following methods.
NOTE
The Layer 3 Switch checks for the existence of an IGP route for 0.0.0.0/0 in the IP route table before
creating a local BGP route for 0.0.0.0/0.
To enable the router to originate and advertise a default BGP4 route, enter the following command.
TurboIron(config-bgp-router)#default-information-originate
Syntax: [no] default-information-originate
Changing the default MED (Metric) used for
route redistribution
The Layer 3 Switch can redistribute directly connected routes, static IP routes, RIP routes, and
OSPF routes into BGP4. The MED (metric) is a global parameter that specifies the cost that will be
applied to all routes by default when they are redistributed into BGP4. When routes are selected,
lower metric values are preferred over higher metric values. The default BGP4 MED value is 0 and
can be assigned a value from 0 – 4294967295.
NOTE
RIP and OSPF also have default metric parameters. The parameters are set independently for each
protocol and have different ranges.
To change the default metric to 40, enter the following command.
TurboIron(config-bgp-router)#default-metric 40
Syntax: default-metric <num>
The <num> indicates the metric and can be a value from 0 – 4294967295.