area nssa (OSPF)

To configure an area as an Open Shortest Path First (OSPF) not-so-stubby (NSSA) area, use the area nssa command. To remove the NSSA area, use the no form of this command.

area area-id nssa [ default-information-originate [ route-map map-name ]] [ no-redistribution ] [ no-summary ] [ translate type7 [ always | never ] [ suppress-fa ]]

no area area-id nssa [ default-information-originate [ route-map map-name ]] [ no-redistribution ] [ no-summary ] [ translate type7 [ always | never ] [ suppress-fa ]]

Syntax Description

area-id
Identifier for the OSPF NSSA area. The area ID can be from 0 to 4294967295 or an IP address.
default-information-
originate
(Optional) Generates a Type 7 default into the NSSA area. This keyword takes effect only on NSSA area border router (ABR) or NSSA autonomous system border router (ASBR).
route-map map-name
(Optional) Filters the Type 7 default generation based on the route map. The map-name argument can be any alphanumeric string up to 63 characters.
no-redistribution
(Optional) Blocks redistributed link-state advertisements (LSAs) from entering this NSSA area. Use this keyword when the router is both an NSSA ASBR and an NSSA ABR and you want the redistribute command to import routes into the normal areas but not into the NSSA area.
no-summary
(Optional) Allows an area to be an NSSA area but not have summary routes injected into it.
translate type7
(Optional) Translates Type 7 LSAs to type 5 LSAs.
always
(Optional) Always translates LSAs.
never
(Optional) Never translates LSAs.
suppress-fa
(Optional) Suppresses the forwarding address in translated LSAs. The ABR uses 0.0.0.0 as the forwarding IPv4 address.

Command Default

None

Command Modes

Router configuration mode

Command History

Release
Modification
5.0(3)N1(1)
This command was introduced.

Usage Guidelines

Use the area nssa command to create an NSSA area in an OSPF autonomous system. We recommend that you understand the network topology before configuring forwarding address suppression for translated LSAs. Suboptimal routing might result because there might be better paths to reach the destination’s forwarding address.

This command requires the LAN Base Services license.

Examples

This example shows how to configure area 1 as an NSSA area:

switch(config)# router ospf 10
switch(config-router)# area 1 nssa
switch(config-router)#
 

This example shows how to configure area 1 as an NSSA area and translate Type 7 LSAs from area 1 to Type 5 LSAs, but not place the Type 7 forwarding address into the Type 5 LSAs. (OSPF places 0.0.0.0 as the forwarding address in the Type 5 LSAs.)

switch(config)# router ospf 2
switch(config-router)# area 1 nssa translate type7 suppress-fa
switch(config-router)#
 

Related Commands

Command
Description
copy running-config startup-config
Saves the configuration changes to the startup configuration file.
redistribute
Redistributes routes learned from one routing protocol to another routing protocol domain.
show ip ospf
Displays OSPF information.