ECS4660-28F_Management Guide-R03

C HAPTER 51 | IP Routing Commands
Open Shortest Path First (OSPFv2)
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EXAMPLE
This example creates a stub area 10.3.0.0, and assigns all interfaces with
class B addresses 10.3.x.x to the NSSA. It also instructs the router to
generate external LSAs into the NSSA when it is an NSSA ABR or NSSA
ASBR.
Console(config-router)#area 10.3.0.0 nssa default-information-originate
Console(config-router)#network 10.3.0.0 255.255.0.0 area 10.2.0.0
Console(config-router)#
area stub This command defines a stub area. To remove a stub, use the no form
without the optional keyword. To remove the summary attribute, use the
no form with the summary keyword.
SYNTAX
[no] area area-id stub [no-summary]
area-id - Identifies the stub area. The area ID can be in the form of
an IPv4 address or as a four octet unsigned integer ranging from
0-4294967295.
no-summary - Stops an Area Border Router (ABR) from sending
summary link advertisements into the stub area.
COMMAND MODE
Router Configuration
DEFAULT SETTING
No stub is configured.
Summary advertisement are sent into the stub.
COMMAND USAGE
◆ All routers in a stub must be configured with the same area ID.
◆ Routing table space is saved in a stub by blocking Type-4 AS summary
LSAs and Type 5 external LSAs. The default setting for this command
completely isolates the stub by blocking Type-3 summary LSAs that
advertise the default route for destinations external to the local area or
the autonomous system.
◆ Use the no-summary parameter of this command on the ABR attached
to the stub to define a totally stubby area. Define an area as a totally
stubby area only if routers in the area do not require summary LSAs
from other areas.
◆ Use the area default-cost command to specify the cost of a default
summary route sent into a stub by an ABR attached to the stub area.