Configuration Guide User guide

1240 FastIron Configuration Guide
53-1002494-01
Configuring OSPF
FIGURE 162 OSPF network containing an NSSA
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 1.1.1.1 as an NSSA, enter the following commands.
Brocade(config)#router ospf
Brocade(config-ospf-router)#area 1.1.1.1 nssa 1
Brocade(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 a number, the number can be from 0 through 18.
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 through 16777215. There is no default. Normal areas do not use the cost parameter.
Alternatively, the default-information-originate parameter causes the Layer 3 Switch to inject the
default route into the NSSA.
RIP Domain
FastIron Layer 3
Switch
FastIron Layer 3
Switch
FastIron Layer 3
Switch
NSSA Area 1.1.1.1
Internal ASBR
OSPF ABR
OSPF Area 0
Backbone