Brocade Communications Systems FastIron SX 1600, Configuration Manual, Page: 294 / 593

– ABRs translate type 7 LSAs into type 5 External LSAs, which can then be flooded throughout the AS. You can configure
address ranges on the ABR of an NSSA so that the ABR converts multiple type-7 External LSAs received from the NSSA
into a single type-5 External LSA.
When an NSSA contains more than one ABR, OSPFv3 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, OSPFv3 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.
For example, to set up OSPFv3 areas 10.70.12.10, 10.70.12.11, 10.70.12.12, and 10.70.12.13, enter the following commands.
device(config-ospf6-router)# area 10.70.12.10
device(config-ospf6-router)# area 10.70.12.11
device(config-ospf6-router)# area 10.70.12.12
device(config-ospf6-router)# area 10.70.12.13
Syntax: [no] area { number | ipv4-address }
The number and ipv4-address parameters specify the area number, which can be a number or in IPv4 address format.
NOTE
You can assign only one area on a device interface.
Assigning a totally stubby area
By default, the device sends summary LSAs (type 3 LSAs) into stub areas. You can reduce the number of LSAs sent into a stub area by
configuring the device to stop sending summary 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 into a stub area, but the device still accepts summary LSAs from OSPF neighbors
and floods them to other areas. The device can form adjacencies with other routers regardless of whether summarization is enabled or
disabled for areas on each router.
When you 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 Brocade 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.
For example, to disable summary LSAs for stub area 40 and specify an additional metric of 99, enter the following command.
device(config-ospf6-router)# area 40 stub 99 no-summary
Syntax: [no] area { number | ipv4-address } stub metric [ no-summary ]
The number and ipv4-address parameters specify the area number, which can be a number or in IPv4 address format. If you specify a
number, the number can be from 0 through 2,147,483,647.
The stub metric parameter specifies an additional cost for using a route to or from this area and can be from 1 through 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.
Configuring OSPFv3
FastIron Ethernet Switch Layer 3 Routing
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