Brocade TurboIron 24X Series Configuration Guide - Manual (Page 653)

Brocade TurboIron 24X Series Configuration Guide 619
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Configuring OSPF
This example shows two routing domains, a RIP domain and an OSPF domain. The ASBR inside the
NSSA imports external routes from RIP into the NSSA as Type-7 LSAs, which the ASBR floods
throughout the NSSA.
The ABR translates the Type-7 LSAs into Type-5 LSAs. If an area range is configured for the NSSA,
the ABR also summarizes the LSAs into an aggregate LSA before flooding the Type-5 LSAs into the
backbone.
Since the NSSA is partially “stubby” the ABR does not flood external LSAs from the backbone into
the NSSA. To provide access to the rest of the Autonomous System (AS), the ABR generates a
default Type-7 LSA into the NSSA.
Configuring an NSSA
To configure OSPF area 10.1.1.1 as an NSSA, enter the following commands.
TurboIron(config)#router ospf
TurboIron(config-ospf-router)#area 10.1.1.1 nssa 1
TurboIron(config-ospf-router)#write memory
Syntax: area | nssa | default-information-originate
The | parameter specifies the area number, which can be a number or in IP
address format. If you specify an number, the number can be from 0 – 2,147,483,647.
The nssa | default-information-originate parameter specifies that this is a
Not-So-Stubby-Area (NSSA). The specifies an additional cost for using a route to or from this
NSSA and can be from 1 – 16777215. There is no default. Normal areas do not use the cost
parameter. Alternatively, you can use the default-information-originate parameter causes the Layer
3 Switch to inject the default route into the NSSA.
NOTE
The Layer 3 Switch does not inject the default route into an NSSA by default.
NOTE
You can assign one area on a router interface. For example, if the system or chassis module has 16
ports, 16 areas are supported on the chassis or module.
To configure additional parameters for OSPF interfaces in the NSSA, use the ip ospf area…
command at the interface level of the CLI.
Configuring a summary address for the NSSA
If you want the ABR that connects the NSSA to other areas to summarize the routes in the NSSA
before translating them into Type-5 LSAs and flooding them into the other areas, configure a
summary address. The ABR creates an aggregate value based on the summary address. The
aggregate value becomes the address that the ABR advertises instead of advertising the individual
addresses represented by the aggregate.
To configure a summary address in NSSA 10.1.1.1 enter the following commands. This example
assumes that you have already configured NSSA 10.1.1.1.
TurboIron(config)#router ospf
TurboIron(config-ospf-router)#summary-address 10.157.22.1 255.255.0.0
TurboIron(config-ospf-router)#write memory
Syntax: [no] summary address