VLAN is Layer 2 (Ethernet); subnet is Layer 3 (IP). In practice they are usually mapped 1:1.

What Is VLAN?

Q: Why put voice on its own VLAN

To apply QoS priority to voice over data, reducing latency and jitter for better call quality.

Q: How many VLANs can a switch support

802.1Q allows VLAN IDs 1-4094 (4094 total), but per-switch concurrent VLAN limits vary by model.

2026-05-07 2 min readSIPPER Team

VLAN is a Layer 2 segmentation technique that divides one switch into multiple isolated networks, with separate broadcast domains. Used for security and traffic management.

Definition

VLAN (IEEE 802.1Q) tags Ethernet frames with a VLAN ID (1-4094). Switches forward frames only within the same VLAN; cross-VLAN traffic must go through a router or Layer 3 switch.

Usage

Separate Voice VLAN (IP phones), Data VLAN (computers), Guest VLAN (visitor Wi-Fi), Management VLAN (switches / APs). Lets QoS prioritize voice over data.

Related Concepts

Trunk Port (multiple VLANs over one cable), Access Port (single VLAN), Native VLAN (untagged frames).

Frequently Asked Questions

Why put voice on its own VLAN

VLAN vs subnet

How many VLANs can a switch support

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