Dell PowerConnect B-RX - Page 790

714 BigIron RX Series Configuration Guide
53-1002253-01
Configuring OSPF
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• With this feature enabled in the “out” direction, all type 3 LSAs advertised by the ABR,
based on information from this area to all other areas, are filtered by the prefix list. If the
area range command has been configured for this area, Type 3 LSAs that corresponds to
the area range command are treated like any other type 3 LSA.
• Prefixes that are not permitted by the prefix list are implicitly denied.
• The following table displays the behavior for prefix list configurations
Configuring an OSPF area prefix list
To filter prefixes advertised in type 3 link-state advertisements (LSAs) between (OSPF) areas of an
Area Border Router (ABR), use the area prefix-list command in router configuration mode. To
change or cancel the filter, use the no form of this command.
Configuring OSPF ABR type 3 LSA filtering
To filter inter-area routes into a specified area, use the following commands beginning in router
configuration mode.
To configure the router to run an OSPF process, enter commands such as the following.
BigIron RX(config)# router ospf
BigIron RX(config-ospf-router)#
To filter prefixes advertised in type 3 link-state advertisements (LSAs) between (OSPF) areas of an
Area Border Router (ABR), use the area prefix-list command in router configuration mode. To
change or cancel the filter, use the no form of this command.
BigIron RX(config-ospf-router)#area 1 prefix-list area 1 in
To configure the switch to filter inter-area routes out of the specified area, enter a command such
as the following.
BigIron RX(config-ospf-router)# area 10.10.10.1 prefix-list Routesfor20 out
Syntax: [no] area {<area-id> | <area_ip>} prefix-list {prefix-list-name in | out}
The < prefix-list-name > parameter specifies the prefix list name.
The {<area-id> | <area_ip>} parameter specifies the area id in different formats.
TABLE 110 Behavior for prefix list configurations
IP prefix list OSPF area prefix list Event Filtering done
XXX Not defined None No (permit all)
Not defined Defined None Yes (deny all)
Not defined Defined IP prefix list defined Recalculation
Defined (no rules
configured)
Defined None Implicit deny (deny all)
Defined (rules
configured)
Defined IP prefix list deleted Recalculation and deny all
Defined (rules
configured)
Defined IP prefix list rule added or
modified or deleted
Recalculation
Defined (rules
configured)
Defined Area prefix list deleted Recalculation and permit all