H3C S9500 Series Operation Manual page 254

Operation Manual – Routing Protocol
H3C S9500 Series Routing Switches
If you use the default-route-advertise command on an ASBR or ABR of a
common OSPF area, the system generates a Type-5 LSA, advertising the default
route in the OSPF route area.
If you use the default-route-advertise command on an ASBR or ABR of an NSSA,
the system generates a Type-7 LSA, advertising the default route in the NSSA.
This command is invalid for a stub area or a totally stub area.
For an ASBR, the system generates the corresponding Type-5 LSA or Type-7
LSA by default when a default route existed in the routing table.
For an ABR, the system will generate a Type-5 LSA or Type-7 LSA no matter
whether there is a default route in the routing table.
The broadcasting scope of Type-5 LSA or Type-7 LSA advertising the default
route is the same as that of the common Type-5 LSA or Type-7 LSA.
Perform the following configuration in OSPF view.
Table 4-9 Configure OSPF to import the default route
Import the default route to
OSPF
Remove
default route
By default, OSPF does not import the default route.
If you use the always keyword of this command, the system will generate a Type-5 or
Type-7 LSA no matter whether there is default route in the routing table. Be cautious
that the always keyword is only valid for an ASBR.
Because OSPF does not calculate the LSAs it generated during SPF calculation, there
is no default route in the OSPF route on this router. To ensure the correct routing
information, you should configure to import the default route on the router only
connected to the external network.
Note:
After the default-route-advertise command is configured on the OSPF router, this
router becomes an ASBR. For the OSPF router, the default-route-advertise and
import-route commands have the similar effect.
For the ABR or ASBR in the NSSA area, the default-route-advertise and nssa
default-route-advertise commands have the same effect.
Operation
the imported
Command
default-route-advertise [ always | cost value | type
type-value | route-policy route-policy-name ]*
undo default-route-advertise [ always | cost | type
| route-policy ]*
4-12
Chapter 4 OSPF Configuration