21 hands-on OSPF scenarios you build in your own Cisco Modeling Labs instance and grade against the answer key. Focused OSPF configuration and troubleshooting practice for CCNA and CCNP.
A compact, enterprise-clean, 5-node CML lab that builds on OSPF multi-area design. You will enable OSPF across a small core–ABR–branch topology, advertise multiple branch networks in area 10, and summarize them at the ABR using 'area range'. You will verify that specific inter-area routes are replaced by a single summary in area 0 while preserving end-to-end reachability between hosts.
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Build and verify a compact, enterprise-clean multi-area OSPF network with an ABR. Configure area 0 and a non-backbone area, advertise loopbacks and LANs, enforce OSPF hygiene (passive LANs, explicit router-ids), and verify O IA inter-area routes from the endpoints.
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Build a 5-node triangle OSPF topology with a branch and a data center connected by two paths: a direct link and an indirect path via a core router. Implement OSPFv2 with clean hygiene (router-ids, passive on LANs), then influence path selection by adjusting interface cost so branch-to-DC traffic prefers the core path. Verify the chosen path from the end hosts using traceroute and confirm symmetric routing by validating the reverse path.
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Three IOS routers share a true broadcast multi-access segment through a Layer-2 switch. You will deploy OSPFv2, influence the DR/BDR election using interface priorities, and verify full adjacencies to the DR. An alpine client behind RTR-HQ-R3 must reach loopbacks on RTR-HQ-R1 and RTR-HQ-R2 via OSPF-learned routes. The lab emphasizes proper multi-access deployment hygiene (router-ids, passive default, interface selection) and realistic verification from the end host.
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Build a two-router OSPFv2 lab, assign deterministic router-ids using loopbacks, form a clean adjacency from Down through Exchange to FULL, and verify neighbor state and router-ids. End-to-end reachability is validated from real hosts across an enterprise-clean topology.
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Bring up OSPFv2 adjacency between two branch routers over a point-to-point /30, advertise each site’s user LAN and router loopback in area 0, and verify end-to-end pings succeed from the hosts. The baseline ships with addressing and SSH management ready; you will enable and tune OSPF only.
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Build an internal BGP (iBGP) peering between two IOS routers in the same AS over stable Loopback0 addresses, with OSPF providing loopback reachability. Each router originates a /24 from Loopback1 into BGP, and next-hop/peering behavior is validated from end hosts. This lab emphasizes the deterministic neighbor configuration (remote-as, update-source Loopback0, router-id) and exact-match network origination, supported by a minimal, secure OSPF core.
In this CCNP-level lab (BGP Fundamentals Lab 4/10), you will build a small, realistic transit-AS scenario: an external route learned by R1 via eBGP from AS 65003 must be carried across iBGP to R2 inside AS 65001. You will intentionally encounter the classic iBGP next-hop problem (R2 sees an unreachable next-hop for 172.16.30.0/24) and fix it on R1 with neighbor next-hop-self. iBGP peering runs over Loopback0 addresses with reachability provided by OSPF area 0 between R1 and R2. Two hosts validate end-to-end data-plane reachability and routing control-plane state.
Advanced CCNP capstone on a compact 3-router, 2-host CML-Free topology. Restore end-to-end reachability to a remote advertised network by diagnosing and correcting two independent BGP issues on the hub router. The design intentionally combines an eBGP edge (R2–R1) with iBGP over loopbacks (R1–R3 with OSPF reachability) so learners validate neighbor formation, next-hop reachability, and route propagation end-to-end.
Hands-on CCNP OSPF lab comparing broadcast and point-to-point network types. Three routers share a multi-access Ethernet via an access switch to observe DR/BDR election, manipulate interface priorities, and then convert to point-to-point. Includes a user LAN behind R1 and realistic troubleshooting: neighbor stuck in 2-Way due to type mismatch, area mismatch isolating a router, and incorrect interface priority preventing desired DR/BDR roles.
Deploy a 5-node OSPFv2 lab featuring a redundant area 0 triangle (R1–R2–R3) and an ABR (R3) connecting to area 1 with branch networks on R4. A client on R1’s area 0 LAN validates reachability to branch loopback networks summarized by the ABR. You will set explicit router-ids from Loopback0, use passive-interface default, advertise R4’s loopbacks as /24s using ip ospf network point-to-point, and summarize area 1 into a /23 on the ABR. Verify FULL adjacencies, a single O IA summary on R1, and end-to-end connectivity. Troubleshoot an introduced area mismatch and interface/addressing issues.
Build a 3-router triangle with two end-to-end paths between Branch A and the Data Center. Stand up OSPF area 0, create an ECMP condition, then intentionally steer traffic using ip ospf cost. Verify from the end hosts and troubleshoot common OSPF control-plane mismatches.
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.
Build a 5-node CML lab to design OSPFv2 across two areas with an ABR that summarizes non-backbone routes using area range. Validate adjacencies, end-to-end reachability, and that the backbone learns a single summary in place of specific inter-area routes. Intentionally introduce an area mismatch, diagnose why the adjacency does not form, and repair it.
Build and troubleshoot a compact multi-area OSPF design with a single ABR between area 0 and area 10. You will deploy OSPF, observe an adjacency failure caused by an area mismatch on one transit link, repair it, and validate that routes propagate end to end between two user LANs.
Deploy OSPFv2 with MD5 authentication on backbone links, deliberately trigger and diagnose an area mismatch adjacency failure, then fix it and restore end-to-end reachability between two branch hosts in a compact three-router topology.
Hands-on CCNA beginner lab: build a 3-router chain with end hosts, enable OSPFv2 area 0, form full adjacencies, advertise loopbacks and LANs, verify route propagation end-to-end, and intentionally create then resolve an OSPF area mismatch on a transit segment.
Deploy OSPFv2 across a 3-router, 2-LAN branch/core/edge topology. Mark LAN-facing interfaces as passive so they do not send OSPF hellos or form adjacencies. Originate a default route only from the edge router and verify default propagation end-to-end using real client traffic. Includes realistic troubleshooting around missing adjacencies, non-propagating defaults, and unreachable external destinations.
Advanced CCNP OSPFv2 multi-area capstone. Build a three-router line topology with area 10 at the branch, area 0 at the core, and MD5 authentication on the area 0 transit. Advertise all loopbacks and a branch user LAN. Validate end-to-end reachability from the branch host to every router loopback and the core LAN. Includes realistic enterprise management and verification flows.
Deploy OSPFv2 across three routers with unique, loopback-derived router-ids. Observe OSPF neighbor state transitions, advertise loopbacks and LANs, and troubleshoot an adjacency failure caused by a duplicate router-id. Validate full end-to-end reachability from client hosts after fixing the issue.
Advanced multi-area OSPF lab with a realistic two-site design and a WAN ABR. You will deploy OSPF with a backbone (area 0) and a non-backbone area, intentionally create an area mismatch on one transit link to observe the failure, then correct it to restore full reachability. The final build demonstrates solid OSPF hygiene and SSH-only management.
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Open Shortest Path First (OSPF) is the link-state IGP at the heart of the CCNA and CCNP exams, and the protocol you're most likely to touch on day one of an enterprise networking job. Reading about LSAs, areas, and the SPF algorithm only takes you so far — OSPF clicks when you watch adjacencies form, break a neighbor relationship on purpose, and trace why a route did or didn't make it into the table.
Every OSPF lab here ships as a license-free Cisco Modeling Labs topology you build on real Cisco IOS. You'll configure router ospf, advertise networks into the right areas, tune interface cost and reference bandwidth, and verify with show ip ospf neighbor, show ip route ospf, and show ip ospf interface. Scenarios run from a single-area adjacency between two routers up to multi-area designs with an ABR, route summarization, and stub areas — plus deliberate faults (a mismatched area, a passive interface, an MTU or timer mismatch) so you practice the troubleshooting the exam and the job actually test. Upload your export when you finish and it's graded requirement by requirement, so you find out whether your OSPF is genuinely correct, not just whether it looks right.
Yes. Each lab is a license-free YAML package built on CML free-tier images. You import it into your own Cisco Modeling Labs instance, build it there, then upload your configuration to be graded.
Single-area adjacencies, multi-area design with an ABR, cost and reference-bandwidth tuning, route summarization, stub and totally-stubby areas, passive interfaces, default-route origination, and common break/fix faults like area, timer, and MTU mismatches.
Both. The single-area labs map to the CCNA OSPFv2 objectives; the multi-area, summarization, and troubleshooting labs go into CCNP ENARSI depth. Each lab is tagged by track so you can filter to your level.
Study the theory behind these labs — the concept explainer and step-by-step guides.
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