Huawei Quidway S3500 Series Operation Manual page 202

Operation Manual - Routing Protocol
Quidway S3500 Series Ethernet Switches
type-5 LSAs that will be propagated in the OSPF AS. However, the type-5 LSAs will not
reach Area 1 because Area 1 is an NSSA. NSSAs and STUB areas have the same
approach in this aspect.
Similar to a STUB area, the NSSA cannot be configured with virtual links.
RIP RIP
Figure 4-1 NSSA area
Perform the following configuration in OSPF Area view.
Table 4-15 Configuring NSSA of OSPF
Configure an area to be the NSSA area
Cancel the configured NSSA
Configure the default cost value of the
route to the NSSA
Restore the default cost value of the
route to the NSSA area
All the routers connected to the NSSA should use the nssa command to configure the
area with the NSSA attribute.
The keyword default-route-advertise is used to generate the default type-7 LSAs.
When default-route-advertise is configured, the default type-7 LSA route will be
generated on the ABR, even though no default route 0.0.0.0 is in the routing table. On
an ASBR, however, the default type-7 LSA route can be generated only if the default
route 0.0.0.0 is in the routing table.
Executing the keyword no-import-route on the ASBR will prevent the external routes
that OSPF imported through the import-route command from advertising to the NSSA.
Generally, if an NSSA router is both ASBR and ABR, this argument will be used.
The keyword default-cost is used on the ABR attached to the NSSA. Using this
command, you can configure the default route cost on the ABR to NSSA.
By default, the NSSA is not configured, and the cost of the default route to the NSSA is
1.
area 0 area 0
area 2 area 2
Operation
Huawei Technologies Proprietary
NSSA NSSA
ABR ABR
area 1 area 1
NSSA NSSA
RIP RIP
nssa [
no-import-route | no-summary ]*
undo nssa
default-cost cost
undo default-cost
4-14
Chapter 4 OSPF Configuration
NSSA NSSA
ASBR ASBR
Command
default-route-advertise |