Procedure

1. Check whether the area where the device resides is connected to the backbone area.

   Run the display ospf [ process-id ] brief command on the ABR in the area where the device resides to check area configuration.

   OSPF requires that all non-backbone areas remain connected to the backbone area.

   If no backbone area information is configured on the ABR, run the area area-id command in the OSPF view to modify the OSPF area information. Ensure that at least one interface on the ABR runs in the backbone area.

   If some non-backbone areas cannot be connected to the backbone area due to networking restrictions, configure OSPF virtual links to resolve this problem.

2. Check whether the area where the device resides is a totally stub area.

   Run the display current-configuration configuration ospf [ process-id ] command on the device to check the OSPF process configuration.

   If you specify the parameter no-summary (run the stub no-summary command in the OSPF area view) when configuring a non-backbone area as a stub area on the ABR, the area is configured as a totally stub area.

   A totally stub area allows only intra-area routes to be advertised within the area.

   If the area where the device resides is configured as a totally stub area, perform the following configuration based on service requirements:

   • To restore the totally stub area to a common area, run the undo stub command in the OSPF area view on all devices in the area.

   • To restore a totally stub area to a stub area, run the undo stub command in the OSPF area view on the ABR in the area and then run the stub command.

3. Check whether the area where the device resides is a totally NSSA.

   Run the display current-configuration configuration ospf [ process-id ] command on the device to check the OSPF process configuration.

   If you specify the parameter no-summary (run the nssa no-summary command in the OSPF area view) when configuring a non-backbone area as an NSSA on the ABR, the area is configured as a totally NSSA.

   A totally NSSA allows only intra-area routes to be advertised within the area.

   If the area where the device resides is configured as a totally NSSA, perform the following configuration based on service requirements:

   • To restore the totally NSSA to a common area, run the undo nssa command in the OSPF area view on all devices in the area.

   • To restore a totally NSSA to a stub area, run the undo nssa command in the OSPF area view on the ABR in the area and then run the nssa command.