An area can be qualified as a stub or totally stubby when it meets
the following criteria:
- There is a single exit point from that area.
- The area is not needed as a transit area for virtual links.
(Virtual links are discussed at the end of this chapter.)
- No ASBR is internal to the stub area.
- The area is not the backbone area (Area 0).
These criteria are important because a stub/totally stubby area
is configured primarily to exclude external routes. If these
criteria are not met, external links may be injected into the area,
invalidating their stubby nature.
|
|