Minimum Protocol-Independent Routing Properties Configuration
All statements that configure protocol-independent routing properties are optional and do not have to be included in the configuration for the router to operate. However, if you are configuring BGP, you must configure an AS number and a router identifier. For OSPF, the router uses the IP address configured on the loopback interface (lo0) as the router identifier. If no IP address is configured on the loopback interface, the router uses the highest IP address for the router identifier.
