Chapter 15. Controlling the OSPF Router ID
ip-address—. The IP address that is to be used as the OSPF router ID.
Purpose: To configure the OSPF router ID. The default OSPF router ID is the numerically highest IP address of any loopback interface that has been configured on the router. If no loopback interfaces have been configured, then the OSPF router ID is the numerically highest IP address of any active interface. The router ID is a component of every OSPF exchange, including Hello packets and link-state advertisements (LSAs). For multiaccess networks, the OSPF router ID is used in the election of the Designated Router (DR). It is desirable to have an OSPF router ID that does not change. If loopback interfaces ...