OSPF: Could not allocate router id Error Message

OSPF: "Could not allocate router id" Error Message

This message appears in two situations:

• No up/up interface with a valid IP address

• Not enough up interfaces with a valid IP address for multiple OSPF processes

OSPF requires a valid IP address that is up/up so that it can allocate a router ID for the OSPF process. The IP address must be assigned on an up/up interface. If a router fails to allocate router IDs, OSPF will not function. This problem can be corrected by using loopback addresses.

The loopback interface solution works for both situations. Just configure a loopback interface for one process. If you are trying to run more than one process, you might need more than one loopback interface.