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Chapter 5
Interconnecting OSPF Areas
amount of route information that is injected into an area, thus reducing a
router's memory and processor overhead.
We detailed the function of different OSPF Link State Advertisements
(LSAs). We saw how these LSAs could be minimized through the effective
implementation of specific OSPF area types.
Specifically, we examined stub areas, totally stubby areas, and not-so-
stubby areas and showed how these areas can be used to minimize LSAs
advertised into an area. We provided a set of design guidelines and configu-
ration examples. We also showed the syntax required to configure route
summarization at both area border routers and autonomous system bound-
ary routers.
Since all areas need to have a link to the backbone area, we explained how
virtual links could be used to span transit areas in OSPF networks where all
areas are not physically adjacent to the backbone area. We then concluded
with a collection of debug and show commands that can be used to effec-
tively monitor and troubleshoot a multi-area OSPF implementation.
Key Terms
Before taking the exam, make sure you're familiar with the following terms:
transit area
virtual link
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