CCNA Day 4: Inter-VLAN Routing (Router-on-a-Stick)

Archive lab

Deploy router-on-a-stick inter-VLAN routing across a compact branch topology with a distribution and access switch, a hardened 802.1Q trunk, and two user VLANs. Configure VLANs and access/trunk ports, build router subinterfaces, verify end-to-end user reachability, and troubleshoot trunk/native-VLAN/subinterface mismatches.

Learning objectives

• Configure VLANs and access/trunk ports on Layer 2 switches with hardened 802.1Q trunks.
• Configure router subinterfaces for router-on-a-stick inter-VLAN routing.
• Assign hosts to different VLANs and verify inter-VLAN connectivity.
• Verify connected routes and VLAN/trunk interface status.
• Troubleshoot inter-VLAN routing and trunking misconfigurations.

Troubleshooting focus

• Verify every link's interface status and IP addressing (`show ip interface brief`) and correct any interface that is down or misaddressed.
• Confirm each device's running configuration matches the lab objective, and bring any interface, route, or service that is not in its expected state back to health.
• Trace end-to-end reachability with ping/traceroute and isolate the first hop where forwarding fails.