Nokia NRS II Composite (OSPF): Troubleshooting, Verification and Show Commands

Troubleshooting, Verification and Show Commands

This domain tests whether you can prove a diagnosis with SR OS commands rather than guess. Expect scenario questions that give a symptom and ask for the next command or the likely cause.

Command map

• show router ospf neighbor - state, priority, dead time, and which neighbour is DR/BDR.
• show router ospf interface - area, interface type, metric, hello/dead, DR/BDR, authentication, passive state.
• show router ospf database and database extensive - LSA presence and content; summarize for counts.
• show router ospf routes - installed OSPF routes with area, type, cost and next hops.
• show router ospf status and statistics - instance state, SPF runs, packet counters.
• show router ospf virtual-link and sham-link output for those designs.
• OSPFv3 uses the same command family under show router ospf3.

Worked example

A neighbour is stuck in ExStart while the interface shows matching area and timers. Check MTU on both interfaces first, then look for duplicate router IDs. show router ospf neighbor confirms the state; show router ospf interface confirms the parameters; the MTU itself comes from the router interface output.

Traps that cost marks

• Checking only the local side; most mismatches are two-sided.
• Reading show router ospf routes as the LSDB - it is the SPF result.
• Forgetting show router ospf3 exists for IPv6 and running the v2 command on a v3-only problem.
• Ignoring counters: a rising retransmission count points at a specific neighbour, not the whole area.