BigIron RX Series Configuration Guide 70753-1001810-01Configuring OSPF 25Syntax: [no default-information-originate [always] [metric ] [metric-type ]The always parameter advertises the default route regardless of whether the router has a defaultroute. This option is disabled by default.The metric parameter specifies a metric for the default route. If this option is not used, thedefault metric is used for the route.The metric-type parameter specifies the external link type associated with the default routeadvertised into the OSPF routing domain. The can be one of the following:• 1 – Type 1 external route• 2 – Type 2 external routeIf you do not use this option, the default redistribution metric type is used for the route type.NOTEIf you specify a metric and metric type, the values you specify are used even if you do not use thealways option.Configuring a default network routeThe device enables you to specify a candidate default route without the need to specify the nexthop 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 defaultnetwork route as a default route instead.When the software uses the default network route, it also uses the default network route's next hopgateway as the gateway of last resort.This feature is especially useful in environments where network topology changes can make thenext hop gateway unreachable. This feature allows the device to perform default routing even if thedefault network route's default gateway changes.The feature thus differs from standard default routes. When you configure a standard defaultroute, 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 routetable does not contain an explicit default route (0.0.0.0/0), the software uses the default networkroute and automatically uses that route's next hop gateway as the default gateway. If a topologychange occurs and as a result the default network route's next hop gateway changes, the softwarecan still use the default network route.Configuring a default network routeYou can configure up to four default network routes. To configure a default network route, entercommands such as the following.BigIron RX(config)# ip default-network 209.157.22.0BigIron RX(config)# write memorySyntax: ip default-network The parameter specifies the network address.
