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| 6.7 |  | Stub, Totally Stubby, and Not-So-Stubby Areas |
| 6.7.3 |  | Configuring stub and totally stubby areas |

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, there is the option of defining the cost of the default route that is automatically injected in the stub or totally stubby area. Use the following syntax to configure the cost of the default route:

> Router(config-router)#area area-id default-cost cost

| Lab Activity e-Lab Activity: Configuring Stub and Totally stubby Areas In this lab, configure a router to be a stub router and set the cost of the default route.