The problem with RIP is it's not very robust, meaning it lacks the ability of handling larger networks and the capability to effectively determine alternate paths. OSPF is an efficient protocol, supporting speedy recovery from topology changes because OSPF routers can reroute data traffic as necessary. OSPF also minimizes overhead packet traffic when announcing changes by only sending information regarding only the change, instead of the entire routing table. OSPF is a link state routing protocol. OSPF maintains a topological database that stores information related to the state of links within an autonomous network and uses this information to calculate the shortest path.
Many companies incorporate OSPF into their routers.
With OSPF, a router announces its presence by sending a Hello message to each of its possible neighbors. Periodically, each neighbor sends a Hello message to show it's still operational. Therefore, the new router will soon learn of its neighbors as well. Base on the TOS, OSPF calculates the best. For example, OSPF can respond to all eight combinations of IP's TOS bits, which can represent all combinations of delay, throughput, and reliability.