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Layer 3 switches route between VLANs in hardware at wire speed — no external router bottleneck. Here is how to configure SVI-based inter-VLAN routing on a Catalyst 9300.

When you don't have a Layer 3 switch, router-on-a-stick provides inter-VLAN routing via a single physical link split into subinterfaces. Learn when this design is appropriate, how to configure subinterfaces, and why it's a bandwidth bottleneck.

DTP lets switches negotiate trunk formation automatically—but this convenience comes with security risks that make disabling it a best practice in production networks.

Learn the differences between access mode, trunk mode, and dynamic trunking protocol negotiation on Cisco Catalyst switches, and why static configuration is the production standard.

VLANs are more than a configuration checkbox — they change how every frame is tagged, forwarded, and filtered inside the switch. Here's the mechanics.

VLANs let you carve one physical switch into multiple isolated broadcast domains — without buying more hardware. Here's how they work and why every network uses them.