When configuring any OSPF router, you must establish which area assignment to enable the interface for. OSPF has some basic rules when it comes to area assignment. OSPF must be configured with areas. The backbone area 0, or 0.0.0.0, must be configure...
http://www.ebrahma.com/2013/10/how-to-configuring-ospf-in-a-single-area/Labels: Advantages-of-the-OSPF, area0, areas, backbone-area-0, ij-area-0, Network, OSPF, OSPF-design, OSPF-in-one-are, router-ospf