Configuring OSPFv3 Stub Areas

A stub area is a special area in which ABRs do not flood the received AS external routes. Therefore, the number of LSAs is greatly reduced.

Context

To reduce the number of LSAs in the network and enhance OSPFv3 extensibility, define OSPFv3 areas. For some non-backbone areas at the edge of ASs, you can define them as stub areas for further reducing the size of the routing table and the number of LSAs.

Procedure

Access the system view.
system-view
Access the OSPFv3 process view.
ospfv3 [ process-id ]
Access the OSPFv3 area view.
area area-id
Configure the area as a stub area.
stub [ no-summary ]
(Optional) Set the cost value of the default route sent to the stub area.
default-cost cost

By default, the cost of the default route sent to the Stub area is set to 1.

You should set the cost of the default route sent to the Stub area only on the ABR in the Stub area. In addition, the specified parameter no-summary of the stub command only takes effect on the ABR. If parameter no-summary is specified, the ABR only sends the Summary-LSA of a default route to the area, and does not generate other Summary-LSAs. An area without AS-external-LSAs and Summary-LSAs is called a Totally Stub area.