| 1. | OSPF stands for Open Shortest Path First. | IGRP stands for Interior Gateway Routing Protocol. |
| 2. | OSPF works on Dijkstra Algorithm. | IGRP works on Bellman Ford Algorithm. |
| 3. | It is a link state protocol. | It is a distance vector protocol. |
| 4. | It is basically used for larger size organizations in the network. | It is basically used for medium to larger size organizations in the network. |
| 5. | There is no such restriction on the hop count. | It allows maximum hop count up to 255. |
| 6. | It is a more intelligent routing protocol than IGRP. | It is not more intelligent routing protocol. |
| 7. | OSPF routing protocol creates three Tables in the router: Neighbor Table, Database Table, and Routing Table. | IGRP routing protocol creates three tables In the router: Neighbor Table, Topology Table, and Routing Table. |
| 8. | Its administrative distance is 110. | Its administrative distance is 100. |
| 9. | It is an Industry standard routing protocol. | It is a Cisco standard routing protocol. |
| 10. | It calculates the metric in terms of bandwidth. | It calculates the metric In terms of bandwidth, load, and delay. |
| 11. | To calculate the best path SPF algorithm is used. | To calculate the best path distance vector algorithm is used and the load balancing of unequal cost is done by a variance mechanism. |
| 12. | The area no. is used to create a separate administrative boundary. The routers that are within the same area able to exchange the route information with neighbor routers in the network. | The Autonomous System (AS) No. is used to create a separate administrative boundary in the network. |
| 13. | VLSM (Variable Length Subnet Mask) is supported. | It does not provide VLSM (Variable Length Subnet Mask). |