OSPF Stub vs Totally-Stubby: Fault & Recovery

Bundle lab · $29.99

Deploy a compact enterprise multi-area OSPF with a backbone (area 0) and one branch area (area 10). You will configure area 10 as a stub, then transition it to a totally-stubby area from the ABR, validate reduced LSDB and routing tables, and simulate an operational fault (area mismatch) to diagnose adjacency loss and restore full transit. The lab uses three routers and two hosts to verify end-to-end reachability and real-world outcomes.

Learning objectives

• Stand up a multi-area OSPF design with area 0 and an ABR into area 10.
• Implement an OSPF stub area and then convert it to a totally-stubby area on the ABR.
• Validate adjacency states, LSDB content, and routing table differences between stub and totally-stubby.
• Reproduce and resolve an OSPF adjacency loss due to an area mismatch and confirm restored transit.

Troubleshooting focus

• Verify every link's interface status and IP addressing (`show ip interface brief`) and correct any interface that is down or misaddressed.
• Confirm each device's running configuration matches the lab objective, and bring any interface, route, or service that is not in its expected state back to health.
• Trace end-to-end reachability with ping/traceroute and isolate the first hop where forwarding fails.