In my last ISIS tutorial, I mentioned that while ISIS and OSPF are both link state protocols, their actual operation differs greatly.
Cisco CCNP / BSCI Tutorial: Comparing OSPF and ISIS Hellos
While studying to pass the BSCI exam and preparing to earn your CCNP certification, youll quickly notice that while OSPF and ISIS are both link-state protocols, there are a lot of differences between the two.