1. OSPF :
It was developed because of in demand in the internet society to launch a high functionality non-proprietary IGP for the
TCP/IP protocol community.
The OSPF is an intradomain routing protocol and is based on link state routing technology. It has introduced some new concepts that are authentication of routing updates, variable length Subnet masks (VLSM), root summarizations etc.
2. IS-IS :
Intermediate System to Intermediate System is a standardized link-state protocol that was developed to the definitive routing protocol for the
OSI Model.
IS-IS is a Link-state IGP. Link-state protocols are distinguished by the circulation of the information required to build a complete network connectivity map on each participating router. This map is then used to calculate the shortest path to destinations.
Predominantly used in ISP environment.
Difference between OSPF and IS-IS :
