VLAN

A VLAN logically segments a switch network into separate broadcast domains.

Updated: 2026-03-05

Definition

A VLAN (Virtual LAN) separates devices on a switch into different logical networks, even if they share the same physical switch.

VLANs reduce broadcast traffic and improve security by segmentation.

Key points

Each VLAN is a separate broadcast domain
Inter-VLAN routing requires a Layer 3 device (router/L3 switch)
Common in enterprise networks to segment users/servers/voice

Common mistakes

Assuming VLAN alone is strong security (it’s segmentation, not encryption).
Forgetting to configure VLANs consistently across trunk links.

Related exams

Cisco CCNA (200-301)

Free CCNA 200-301 mini test. Continue in the app for offline packs and detailed explanations.

CompTIA Network+ (N10-009)

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