OSPF is a link-state routing protocol:

-Each OSPF router maintains an identical database describing the Autonomous System’s topology

-From this database, a routing table is calculated by constructing a shortest-path tree

Why OSPF?

It is designed to be run internal to a single Autonomous System.

OSPFv2 Advantages:

-OSPF recalculates routes quickly in the face of topological changes, utilizing a minimum of routing protocol traffic.

-OSPF provides support for equal-cost multipath.

-An area routing capability is provided, enabling an additional level of routing protection and a reduction in routing protocol traffic

Network types:

-Point-to-point networks

-Broadcast networks 

-Non-broadcast networks