The largest domain. OSPF is the primary simulation topic — master it completely.

| Topic | File | |-------|------| | Routing Table Components — codes (C/L/S/O), longest prefix match, AD | chapter-3---ip-connectivity/routing-table-components | | Router Forwarding Decisions — CEF, TTL, Layer 2 rewrite per hop | chapter-3---ip-connectivity/router-forwarding-decisions | | Static Routing — network/default/host/floating static, IPv6 static | chapter-3---ip-connectivity/static-routing | | OSPFv2 Fundamentals — neighbor requirements, DR/BDR, cost, states | chapter-3---ip-connectivity/ospfv2-fundamentals | | OSPFv2 Configuration — network statement, passive interface, reference bandwidth | chapter-3---ip-connectivity/ospfv2-configuration | | OSPF Troubleshooting — adjacency states, MTU mismatch, area mismatch | chapter-3---ip-connectivity/ospf-troubleshooting | | First-Hop Redundancy — HSRP, VRRP, GLBP, preemption, virtual MAC | chapter-3---ip-connectivity/first-hop-redundancy | | IPv4 Troubleshooting — ping codes, one-way reachability, missing routes | chapter-3---ip-connectivity/ipv4-troubleshooting |

Priority: OSPF configuration + troubleshooting = the exam. Know all neighbor states and their causes.

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