Scenario guide
How to approach ospf troubleshooting scenarios
OSPF neighbour adjacencies, route advertisements, and DR/BDR elections appear consistently on the CCNA. These questions test whether you can read OSPF state from show commands and identify why two routers fail to reach FULL adjacency or why a route isn't being learned.
Quick answer
OSPF questions usually test neighbour formation, areas, router IDs, route preference, metrics and command-output interpretation.
How OSPF neighbours form and why adjacency can fail.
How router ID, area ID, timers, passive interfaces and authentication affect OSPF.
How OSPF cost influences route selection.
How to read show ip route and show ip ospf neighbor output.