OSPF - 3 Router Lab
📌 Overview
This lab demonstrates OSPF adjacency formation, neighbor discovery, and route exchange using a 3-router straight-line topology. All routers are configured in Area 0, and each router uses its loopback interface as its OSPF router ID.
Routers:
- R1 – Router ID: 1.1.1.1
- R2 – Router ID: 2.2.2.2
- R3 – Router ID: 3.3.3.3
📡 Topology
🔧 Objectives
- Configure IP addresses on all routers
- Enable OSPF on all interfaces
- Advertise loopbacks and connected networks
- Verify OSPF neighbor adjacencies
- Validate that all loopback networks are reachable across the topology
🧪 Commands Used
show ip ospf neighbor
show ip route ospf
show ip protocols
show ip ospf interface
ping <loopback-address>
📈 Results
- Full OSPF adjacencies formed between all routers
- Loopback networks (1.1.1.1, 2.2.2.2, 3.3.3.3) are reachable across all routers
- Routing table shows OSPF-learned routes for each loopback
- Convergence confirmed with ping tests
📁 Configuration Files
- R1.txt – OSPF and IP configuration
- R2.txt – OSPF and IP configuration
- R3.txt – OSPF and IP configuration
📝 Notes / Lessons Learned
- Loopbacks are useful as stable OSPF router IDs
- OSPF adjacency forms only on interfaces with matching hello/dead timers and area configuration
- Network statements determine which interfaces participate in OSPF
- Straight-line topologies illustrate convergence and route propagation clearly