
Configuring IP Services
7-60 117356-A Rev. A
Configuring a Stub Area
A stub area does not import ASEs and may or may not import internal route
summaries. In place of routes to destinations outside the stub, a border router
connected to a stub injects a default route advertisement. When an internal router
encounters a datagram addressed to a destination outside the stub, the router
forwards it to the border router specified in the default route advertisement.
Assume, for example, that the stub area in F
igure 7-1 has been configured to
import no internal or external routing information. Border router 8 receives ASEs
and internal summaries from its interface to the backbone. However, Border
router 8 does not forward the ASEs or summaries to the stub. Instead, it injects a
default route that internal routers use to forward datagrams to destinations beyond
the stub.
Using the BCC
By default, OSPF assumes that the area you define is not a stub area. If the area is
a stub, navigate to the prompt for the area and enter
non-stub false
By default, a border router that injects a default route into a stub area assigns a
cost metric of 1 to that default route. To specify a different cost metric, enter
stub-metric
cost
cost is an integer.
By default, a border router injects network summaries into an attached stub area.
To disable this function, enter
import-summaries false
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