| To configure an area as a stub or
totally stubby area, use the following syntax on all router
interfaces that are configured to belong to that area:
Router(config-router)#area
area-id stub
The optional no-summary
keyword is used only on ABRs. This keyword configures the ABR to
block interarea summaries (Type 3 and Type 4 LSAs). The no-summary
keyword creates a totally stubby area.
The area stub command is configured on each router in the stub
location, which is essential for the routers to become neighbors and
exchange routing information. When this command is configured, the
stub routers exchange hello packets with the E bit set to 0. The E
bit is in the Options field of the hello packet. It indicates that
the area is a stub area. The state of this bit must be agreed upon
otherwise the routers will not become neighbors.
On ABRs only, you also have the
option of defining the cost of the default route that is
automatically injected in the stub/totally stubby area.
You use the following syntax to configure the default route's cost:
Router(config-router)#area
area-id default-cost cost
|