Content

| 6.7 |  | Stub, Totally Stubby, and Not-So-Stubby Areas |
| 6.7.2 |  | Stub and totally stubby area criteria |

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 module.
- No ASBR is internal to the stub area.
- The area is not the backbone area, or Area 0.

These criteria are important because a stub or 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.

| Interactive Media Activity Drag and Drop: ID the Area Upon completion of this activity, the student will be able to identify the difference between stub and totally stubby areas in OSPF.