Understand OSPF.

Very few can explain what actually happens after you enable it.

This single diagram shows the real internal workflow:

1️⃣ Neighbors discovered via Hello packets
2️⃣ Compatibility checks (area, mask, timers)
3️⃣ LSAs exchanged → LSDB built
4️⃣ SPF (Dijkstra) runs
5️⃣ Best path selected by total cost
6️⃣ Neighbors reach FULL state
7️⃣ DR/BDR reduce LSA flooding

If you can’t mentally simulate these 7 steps,
you don’t understand OSPF — you’ve memorized commands.

That’s the difference between:
“I configured OSPF”
vs
“I know why traffic chose that path.”