The stub area is a special area defined by OSPF, which has only one ABR. When an area meets certain requirements, you can configure it as a stub area. In this case, OSPF routes can be quickly aggregated and effectively spread.
After area partition, the number of LSAs in the network decreases, and the OSPF extensibility is enhanced. To reduce its routing table size and the number of LSAs, you can configure some non-backbone areas on the AS border as stub area.
You must use the stub command to configure the area with Stub functions on the FWs that are connected to the stub area.
ospf [ process-id ]
area area-id
stub [ no-summary ]
The parameter in the stub command is valid only when you configure the command on ABRs.
default-cost cost
The default-cost command can be configured on ABRs only.