CCNA Foundations: OSPF Day 5 — Multi-Area OSPF & the ABR
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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OSPFv2 Multi-Area with ABR Summarization (Redundant Core)
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.
OSPF Stub vs Totally-Stubby: Fault & Recovery
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.
OSPF Multi-Area: ABR Area Mismatch and Route Repair
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.
OSPFv2 Multi-Area Capstone: 3-Rtr Line, Auth, LAN Host Intact
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.