Brocade Virtual ADX Switch and Router Guide (Supporting ADX v03.1.00) - Manual (Page 126)

112 Brocade Virtual ADX Switch and Router Guide
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Configuring OSPF
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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 LSA(s) 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.
Virtual ADX(config)# router ospf
Virtual ADX(config-ospf-router)# area 10.1.1.1 nssa 1
Virtual ADX(config-ospf-router)# write memory
Syntax: area num | ip-addr nssa cost | default-information-originate
The num | ip-addr 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 cost | default-information-originate parameter specifies that this is a Not-So-Stubby-Area
(NSSA). The cost 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 an address range 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 an
address range. The ABR creates an aggregate value based on the address range. The aggregate
value becomes the address that the ABR advertises instead of advertising the individual addresses
represented by the aggregate. You can configure up to 32 ranges in an OSPF area.
To configure an address range in NSSA 10.1.1.1, enter the following commands. This example
assumes that you have already configured NSSA 10.1.1.1.
Virtual ADX(config)# router ospf
Virtual ADX(config-ospf-router)# area 10.1.1.1 range 10.157.22.1 255.255.0.0
Virtual ADX(config-ospf-router)# write memory
Syntax: [no] area num | ip-addr range ip-addr ip-mask [advertise | not-advertise]
The num | ip-addr parameter specifies the area number, which can be in IP address format. If you
specify a number, the number can be from 0 – 2,147,483,647.