Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 257)

When an NSSA contains more than one ABR, OSPF elects one of the ABRs to perform the LSA
translation for NSSA. OSPF elects the ABR with the highest router ID. If the elected ABR becomes
unavailable, OSPF automatically elects the ABR with the next highest router ID to take over translation
of LSAs for the NSSA. The election process for NSSA ABRs is automatic.
To set up the OSPF areas use the following method.
device(config-ospf-router)# area 192.5.1.0
device(config-ospf-router)# area 200.5.0.0
device(config-ospf-router)# area 195.5.0.0
device(config-ospf-router)# area 0.0.0.0
device(config-ospf-router)# write memory
Syntax: [no] area { num | ip-addr }
The num and ip-addr parameters specify the area number, which can be a number or in IP address
format. If you specify a number, the number can be from 0 - 2,147,483,647.
Assign a totally stubby area
By default, the device sends summary LSAs (LSA type 3) into stub areas. You can further reduce the
number of link state advertisements (LSA) sent into a stub area by configuring the device to stop
sending summary LSAs (type 3 LSAs) into the area. You can disable the summary LSAs when you are
configuring the stub area or later after you have configured the area.
This feature disables origination of summary LSAs, but the device still accepts summary LSAs from
OSPF neighbors and floods them to other neighbors. The device can form adjacencies with other
routers regardless of whether summarization is enabled or disabled for areas on each router.
When you enter a command to disable the summary LSAs, the change takes effect immediately. If you
apply the option to a previously configured area, the device flushes all of the summary LSAs it has
generated (as an ABR) from the area.
NOTE
This feature applies only when the device is configured as an Area Border Router (ABR) for the area.
To completely prevent summary LSAs from being sent to the area, disable the summary LSAs on each
OSPF router that is an ABR for the area.
To disable summary LSAs for a stub area, enter commands such as the following.
device(config-ospf-router)# area 40 stub 99 no-summary
Syntax: [no] area { num | ip-addr stub cost [ no-summary ] }
The num and ip-addr parameters specify the area number, which can be a number or in IP address
format. If you specify a number, the number can be from 0 - 2,147,483,647.
The stub cost parameter specifies an additional cost for using a route to or from this area and can be
from 1 - 16777215. There is no default. Normal areas do not use the cost parameter.
The no-summary parameter applies only to stub areas and disables summary LSAs from being sent
into the area.
Assign a Not-So-Stubby Area (NSSA)
The OSPF Not So Stubby Area (NSSA) feature enables you to configure OSPF areas that provide the
benefits of stub areas, but that also are capable of importing external route information. OSPF does not
flood external routes from other areas into an NSSA, but does translate and flood route information from
the NSSA into other areas such as the backbone.
Assign a totally stubby area
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