A reference diagram showing how VLANs create logically separate broadcast domains on shared physical switching hardware — the foundational concept behind network segmentation.
A VLAN is a logical segmentation, not a physical one — all four groups share the same physical switch, but the switch enforces that traffic stays isolated within each virtual network unless explicitly routed between them.
Last reviewed 2026-09-30
What this shows
How a single physical switch carries multiple logically isolated VLANs, and why that logical separation (not physical hardware) is what enforces network segmentation in most business network designs.
Intended audience
IT and network administrators designing or reviewing a segmentation approach; non-network-specialist IT leaders who need the concept explained clearly.
Methodology
Reflects standard IEEE 802.1Q VLAN tagging concepts as applied in typical business network design — a generic illustration, not a specific vendor’s switch configuration.
Limitations
Shows the logical segmentation concept, not a complete network security design — VLANs alone do not constitute a full segmentation or zero-trust strategy without accompanying firewall/ACL policy.
Citing this resource
To reference this resource, link directly to this page — e.g. “IT KORR’s VLAN Segmentation on a Single Physical Switch, itkorr.com/technical-resources/vlan-segmentation.” This page may be linked to and quoted from with attribution; republishing or redistributing the diagram itself requires separate permission.
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