A hands-on lab demonstrating OSPF backbone reachability using a virtual link. Step-by-step topology, practical Cisco IOS config examples, verification commands, and troubleshooting tips — perfect for network engineers, students preparing for CCNA/CCNP, or anyone learning OSPF design 🚀 Highlights Clear multi-area OSPF topology with Area 0, Area 2, NSSA (Area 3), and a non-backbone Area (Area 10) connected via a virtual link. Complete configuration examples for router interfaces and OSPF process (virtual link creation). Verification commands and troubleshooting tips. Accompanying step-by-step video tutorial on YouTube.(computer scienceکمپیوتر ساینس)
🛠️ Prerequisites Basic familiarity with Cisco IOS (or similar vendor) CLI. Packet Tracer / GNS3 / EVE-NG for lab deployment (recommended). Routers with OSPF support.
🔍 Verification & Useful Commands show ip ospf neighbor show ip ospf virtual-links show ip ospf show ip route (confirm routes from the remote area are in the RIB) debug ip ospf adj (use carefully in lab only)
🛑 Troubleshooting Tips Virtual links require OSPF adjacency across the transit area — the transit area must be configured on intermediate routers and not be a stub. Ensure router IDs are unique. Use show ip ospf database to confirm LSAs and the virtual link’s LSAs. If adjacency won’t form, check MTU mismatches, hello/dead timers, and authentication mismatch. 🎥 Video Tutorial
A full, narrated step-by-step walkthrough is available on YouTube — (https://www.youtube.com/channel/UCAvnuCGBgYjizY3lCZ7Brrw?sub_confirmation=1). The video shows topology setup, full config on each router, verification and troubleshooting.
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License
Feel free to reuse these configs and topology for study. If you publish derivative content, a short attribution is appreciated.
Enjoy the lab — and let me know if you want additional variants (e.g., with authentication, LSA filtering, or OSPF summarization)!