OSPF is by far the most popular and important protocol in use today.

Most important features of OSPF:

1. Its open source !
2. Very fast convergence time, ( a tad close to even EIGRP )
3. Link-state routing protocol
4. Supports multiple, equal cost routes to the same destination
5. Supports both IPv4 and IPv6
6. Uses Dijkstra’s algorithm to find the shortest path tree and follows that by populating the routing table with resulting best path.
7. Allows creation of areas and autonomous system
8. Minimizes routing update traffic
9. Supports VLSM/CIDR
10. Unlimited hop count (unlike RIP)
11. Supports Multi-vendor deployment.