VLAN Segmentation: Broadcast-Domain Isolation

Bundle lab · $29.99

Build VLANs across two access switches with an 802.1Q trunk and a router uplink. Verify that hosts in the same VLAN can communicate (even across switches) while hosts in different VLANs cannot. Then troubleshoot a failure caused by a trunk allow-list misconfiguration.

Learning objectives

• Create VLANs to segment a Layer-2 network into separate broadcast domains.
• Assign access ports to the correct VLANs and harden them with edge features.
• Configure 802.1Q trunks, native VLANs, and explicit allow-lists between switches and to a router-on-a-stick uplink.
• Verify intra-VLAN reachability across switches and demonstrate inter-VLAN isolation without routing.
• Troubleshoot cross-switch VLAN failures caused by missing VLANs in trunk allow-lists.

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.