A small Router-on-a-Stick (ROAS) topology built in Cisco Packet Tracer. It demonstrates VLAN segmentation and inter-VLAN routing using a single trunk link between a Layer 2 switch and a router.

VLANs

• VLAN 10 – Management
• VLAN 20 – Finance
• VLAN 30 – Engineering
• VLAN 40 – HR

Key Concepts Demonstrated

• VLAN creation and access port assignment
• 802.1Q trunk configuration
• Router subinterfaces
• Inter-VLAN routing
• Default gateway configuration per VLAN

Result

• All hosts within the same VLAN can communicate, and inter-VLAN communication is achieved through router subinterfaces over a single trunk link.

What I Learned

• How trunk links carry multiple VLANs over a single interface
• How router subinterfaces process tagged traffic
• How default gateways allow inter-VLAN communication

Topology