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NOTE:
Virtual links cannot transit totally stub areas.
Configuring an NSSA area
A stub area cannot redistribute routes. Configure the area as an NSSA area to allow for route
redistribution by keeping other stub area characteristics.
To configure an NSSA area:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter OSPF view.
ospf
[
process-id
|
router-id
router-id
|
vpn-instance
vpn-instance-name
] *
N/A
3.
Enter area view.
area
area-id
N/A
4.
Configure the area as an
NSSA area.
nssa
[
default-route-advertise
|
no-import-route
|
no-summary
|
translate-always
|
translator-stability-interval
value
]
*
Not configured by default.
You must use the
nssa
command on
all the routers attached to an NSSA
area.
5.
Specify a cost for the default
route advertised to the
NSSA area.
default-cost
cost
Optional.
1 by default.
The
default-cost
command is
available only on the ABR/ASBR of
an NSSA area.
Configuring a virtual link
Non-backbone areas exchange routing information via the backbone area. Connectivity between the
backbone and non-backbone areas and within the backbone must be maintained.
If the required physical links are not available for this connectivity maintenance, you can configure virtual
links to resolve it.
To configure a virtual link:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter OSPF view.
ospf
[
process-id
|
router-id
router-id
|
vpn-instance
vpn-instance-name
] *
N/A
3.
Enter area view.
area
area-id
N/A