Hello Starts The Neighbor
What has to match before an OSPF Hello can even start a neighbor relationship?
Open Session 01Sessions
OSPF track sessions
Neighbor State Machine
How does a received Hello turn into Init, 2-Way, or Full?
DR And BDR Election
If several routers share one broadcast segment, how does the code pick DR and BDR?
Open Session 03LSA As An Object
What does a Router-LSA have to contain before flood and SPF can use it?
Open Session 04Flooding Decides Where The LSA Goes
Once a newer LSA is received, where should it be forwarded next?
Open Session 05LSDB Keeps The Version
How does the LSDB decide whether a newly received Router-LSA replaces the old one?
Open Session 06SPF Turns The LSDB Into A Tree
What are the exact inputs to SPF, and what object does SPF return?
Open Session 07The Tree Becomes Routes
How does the shortest-path tree turn into actual reachable prefixes?
Open Session 08Cost Picks The Winner
If the same prefix appears more than once, which route wins?
Open Session 09Topology Change Recomputes The RIB
When a Router-LSA changes, which part of the route table has to be recomputed?
Open Session 10Area Boundaries Rewrite The View
What changes when routes cross an area boundary through an ABR-like summary step?
Open Session 11Build The Toy OSPF Speaker Loop
What does the smallest readable OSPF speaker look like when Hello, LSDB, SPF, and area summary are connected?
Open Session 12