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CCNP · ENARSIAdvanced

OSPF Multi-Area & Redistribution

An area range that was accepted, is in the running config, and summarizes nothing at all. Find the router it belongs on, live, right below.

Interactive simRoutingOSPFRedistribution

Symptom

Areas and LSA types, route summarization, and controlled redistribution between OSPF and EIGRP.

Your mission

Inspect, recover, then verify

Format

Cisco IOS CLI

Start interactive labSee the investigation plan ↓Need a hint? Reveal the root cause ↓
OSPF Multi-Area: Summary Never Reaches the Backbone

Investigate before you configure.

Use the CLI evidence to isolate the fault, make the smallest safe correction, then verify the network state changed.

Observe the symptom and link state.

Diagnose by comparing the protocol evidence.

Verify the expected device state and confirm the original symptom is resolved.

Console access: R1 (Area 0 core) · R2 (ABR area 0/3) · R3 (ABR area 0/2)

This workspace stacks for portrait phones. Rotate to landscape for the full split-screen console.

Need a hint?

Reveal the root cause when you're ready.

Try the investigation first, then use this as your escape hatch, not a dead end.

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Lab debrief

Turn the session into a repeatable troubleshooting pattern.

Use this reference after your attempt: first explain the symptom, then verify the evidence, then confirm the repair.

The problem

Area 3's routers can see routes from Area 0, but a static host behind Area 3 is unreachable from Area 0, and the summarization you'd expect at the ABR isn't showing up in the routing table at all.

What you'll practice

  • Design and configure a multi-area OSPF topology (Area 0 + non-backbone areas)
  • Identify and interpret LSA types across area boundaries
  • Summarize routes at ABRs and ASBRs
  • Redistribute routes between OSPF and EIGRP with route-maps and filtering
  • Troubleshoot suboptimal routing and redistribution loops

The topology

Five Cisco IOS routers form a hub-and-spoke multi-area OSPF network, one core router in Area 0 connecting four area routers, so you can practice area design, summarization and redistribution without a simulated/limited IOS subset.

Commands to run yourself

The real diagnostic commands for this lab, copy-paste ready. Run these in the same order to reproduce the investigation on your own session.

Find the real ABRs
show ip ospf border-routers
Read what the backbone learns
show ip route ospf
Inspect an ABR's OSPF config
show running-config | section router ospf
OSPF multi-area redistributionFive routers across the backbone, Area 1, Area 2 and Area 3.AREA 3Gi0/010.0.1.0/30Gi0/110.0.2.0/30Gi0/210.0.3.0/30Gi0/1 to Gi0/010.0.34.0/30R0RID 100.100.100.100Area 0 onlyR1RID 1.1.1.1Area 0 + Lo1R2RID 2.2.2.2Area 0 + 2 · ASBRR3RID 3.3.3.3Area 0 + Area 3R4RID 4.4.4.4Area 3 onlyLo99 172.16.99.99/32AREA 1 (Lo1)AREA 2 (via R2)Trace the Area 3 route to R0R4's loopback route must reach the backbone.

Fact-checked references

The commands and behaviour in this lab were checked against these primary references.

Frequently asked

What runs in the browser, and how does it differ from a live lab?

This page uses a focused browser simulation with modeled commands and device state. It is not a full device operating system. Hosted Network Lab sessions are a separate product; check the available topology and booking details before purchasing hosted time.

Does this cover the CCNP ENARSI exam topics?

Yes. Multi-area OSPF, LSA types, summarization and redistribution are core ENARSI (300-410) blueprint topics.

Ready to run this lab yourself?

No setup, no image sourcing. Book a session or ask for a live demo.

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