OSPF Virtual Links

Configuring OSPF Stub Areas

Three types of OSPF stub areas must be configured:

• Stub

• NSSA

• Totally stubby

To configure stub areas, use the area command followed by what type of stub area you want to configure. All routers on the same IP network must be in the same area, and area parameters also must match for neighbors and adjacencies to form.

To configure Area X as a stub area, enter the following:

  Router(config-route)area X stub  

To configure Area X as a not-so-stubby area, enter the following:

  Router(config-route)area   X   nssa {default-information originate}.  

Use the keyword default-information originate on the area statement in the preceding example to propagate a default route to an NSSA area.

To configure Area X as a totally stubby area, enter the following:

  Router(config-route)area X stub no-summary