A diagram-driven workspace for single-area OSPFv2. Watch neighbors form, build Cisco IOS configurations, inject realistic faults, and drill CCNA-level verification — all on one three-router topology.
Topology summary (text)
No Hello has been received yet, or the neighbor was just cleared. The router may send Hellos if OSPF is enabled on the interface.
Packets this stage: Hello — Discovers/maintains neighbors; carries timers, area, router ID, DR/BDR on multiaccess.
Broadcast/P2P defaults: Hello 10s, Dead 40s (4× Hello).
Values depend on OSPF network type and can be changed per interface.
Point-to-point links do not use DR/BDR. This panel models a shared Ethernet segment.
DR: 2.2.2.2 · BDR: 3.3.3.3
Priority 0 = DROTHER only. Election is non-preemptive after formation.
Neighbor table
Who am I connected to?
show ip ospf neighborLSDB
What topology information do I know?
show ip ospf databaseRouting table
Which path will I actually use?
show ip route ospfLowest cost from R1: 1 via R1 → R3
Cost = reference BW ÷ interface BW (default ref 100 Mbps). Use auto-cost reference-bandwidth on modern networks.
Optional IPv6 note: OSPFv3 is commonly used with IPv6. This lab focuses on single-area OSPFv2 for CCNA.