Dell BigIron RX Series, Configuration Manual

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710 BigIron RX Series Configuration Guide
53-1002253-01
Configuring OSPF
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The metric-type <type> parameter specifies the external link type associated with the default route
advertised into the OSPF routing domain. The <type> can be one of the following:
•
1 – Type 1 external route
•
2 – Type 2 external route
If you do not use this option, the default redistribution metric type is used for the route type.
NOTE
If you specify a metric and metric type, the values you specify are used even if you do not use the
always option.
Configuring a default network route
The BigIron RX enables you to specify a candidate default route without the need to specify the next
hop gateway. If the IP route table does not contain an explicit default route (for example, 0.0.0.0/0)
or propagate an explicit default route through routing protocols, the software can use the default
network route as a default route instead.
When the software uses the default network route, it also uses the default network route's next hop
gateway as the gateway of last resort.
This feature is especially useful in environments where network topology changes can make the
next hop gateway unreachable. This feature allows the BigIron RX to perform default routing even if
the default network route's default gateway changes.
The feature thus differs from standard default routes. When you configure a standard default
route, you also specify the next hop gateway. If a topology change makes the gateway unreachable,
the default route becomes unusable.
For example, if you configure 10.10.10.0/24 as a candidate default network route, if the IP route
table does not contain an explicit default route (0.0.0.0/0), the software uses the default network
route and automatically uses that route's next hop gateway as the default gateway. If a topology
change occurs and as a result the default network route's next hop gateway changes, the software
can still use the default network route.
Configuring a default network route
You can configure up to four default network routes. To configure a default network route, enter
commands such as the following.
BigIron RX(config)# ip default-network 209.157.22.0
BigIron RX(config)# write memory
Syntax: ip default-network <ip-addr>
The <ip-addr> parameter specifies the network address.
To verify that the route is in the route table, enter the following command at any level of the CLI.
BigIron RX(config)# show ip route
Total number of IP routes: 2
Start index: 1 B:BGP D:Connected R:RIP S:Static O:OSPF *:Candidate default
Destination Gateway Port Cost Type
1 209.157.20.0 0.0.0.0 lb1 1 D
2 209.157.22.0 0.0.0.0 4/11 1 *D