An administrator types in the command router ospf 1 and receives the error message:
“OSPF process 1 cannot start.” (Output is omitted.) What should be done to correctly set up OSPF?
A.
Ensure that an interface has been configured with an IP address.
B.
Ensure that an interface has been configured with an IP address and is up.
C.
Ensure that IP classless is enabled.
D.
Ensure that the interfaces can ping their directly connected neighbors.
Explanation:
A loopback interface can override the OSPF router ID. If a loopback interface exists, the router ID
is the highest IP address on any active loopback interface.
The OSPF router-id command can be used to override the OSPF router ID.
Using a loopback interface or a router-id command is recommended for stability.