Command Line Interface
10691553-KDU 137 365 Uen D 2006-06-16
• no-redistribution - Use this keyword when the router is an
NSSA Area Border Router (ABR) and the redistribute
command is required to import routes only into normal areas, and
not into the NSSA. In other words, this keyword prevents the NSSA
ABR from advertising external routing information (learned through
routers in other areas) into the NSSA.
• default-information-originate - When the router is an
NSSA Area Border Router (ABR) or an NSSA Autonomous System
Boundary Router (ASBR), this parameter causes it to generate
Type-7 default LSA into the NSSA. This default provides a route to
other areas within the AS for an NSSA ABR, or to areas outside the
AS for an NSSA ASBR.
Command Mode
Router Configuration
Default Setting
No NSSA is configured.
Command Usage
• All routers in a NSSA must be configured with the same area ID.
• An NSSA is similar to a stub, because when the router is an ABR, it can
send a default route for other areas in the AS into the NSSA using the
default-information-originate keyword. However, an NSSA is
different from a stub, because when the router is an ASBR, it can import
a default external AS route (for routing protocol domains adjacent to the
NSSA but not within the OSPF AS) into the NSSA using the default-
information-originate keyword.
• External routes advertised into an NSSA can include network
destinations outside the AS learned through OSPF, the default route,
static routes, routes imported from other routing protocols such as RIP,
and networks directly connected to the router that are not running
OSPF.
•
NSSA external LSAs (Type 7) are converted by any ABR adjacent to the
NSSA
into external LSAs (Type-5), and propagated into other areas
within the AS.
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