Configuring a stub area

Configure stub areas to control external advertisements flooding and to minimize the size of the topological databases on an area's routers. A stub area cannot also be configured as an NSSA.

By default, summary route advertisements are sent into stub areas. The no form of the summary command disables sending summary route advertisements and only the default route is advertised by the ABR. This example retains the default so the command is not entered.

If this area is configured as a transit area for a virtual link, then existing virtual links of a non-stub or NSSA area are removed when its designation is changed to NSSA or stub.

Stub areas for OSPF3 are configured the same as OSPF stub areas.

Use the following CLI syntax to configure virtual links.

CLI syntax

ospf
  area area-id
  stub
  default-metric metric
  summaries

Use the following CLI syntax to configure virtual links for OSPF3.

CLI syntax

ospf
ospf3
  area area-id
  stub
  default-metric metric
  summaries

The following displays a stub configuration example:

ALA-A>config>router>ospf>area># info
----------------------------------------------
...
            area 0.0.0.0
            exit
            area 0.0.0.20
                stub
                exit
            exit
...
----------------------------------------------
ALA-A>config>router>ospf#

The following displays a stub configuration example:

ALA-A>config>router>ospf>area># info
----------------------------------------------
...
            area 0.0.0.0
            exit
            area 0.0.0.20
                stub
                exit
            exit
...
----------------------------------------------
ALA-A>config>router>ospf#

The following displays a stub configuration example for the OSPF3:

A:ALA-48>config>router>ospf3>area# info
----------------------------------------------
                stub
                    default-metric 5000
                exit
----------------------------------------------
A:ALA-48>config>router>ospf3>area#