OSPF stands for Open Shortest Path First which is an open standard routing protocol that’s been implemented by lots of network vendors, including Cisco. If we have multiple routers and not all of them are Cisco, then we can’t use EIGRP, so our remaining protocol options are basically RIP RIPv2 and OSPF. If it’s a large network, then, we cannot use RIP protocol really, our only options are OSPF and something called route redistribution. OSPF uses the Dijkstra algorithm for best path selection in the Network. First, the shortest path is constructed, and then the routing table contains the resulting best paths. OSPF converges is quick, although perhaps not as quickly as EIGRP, it also supports both IP and IPv6 routing protocols.