VLANs (Virtual LANs)

Network segmentation for performance & security


+ What is a VLAN?

A VLAN (Virtual Local Area Network) is a logical segmentation of a physical network. Devices in different VLANs behave as if they are on separate networks.

+ Why do we need VLANs?
  • Improves network security
  • Reduces broadcast traffic
  • Better performance
  • Logical separation without extra hardware
+ VLAN vs Physical Network Separation

Without VLANs, separate switches are required for each department. VLANs allow multiple departments to share the same switch while remaining isolated.

+ What is an Access Port?

An access port carries traffic for only one VLAN. End devices like PCs and printers connect to access ports.

+ What is a Trunk Port?

A trunk port carries traffic for multiple VLANs using VLAN tags. It is commonly used between switches.

+ What is IEEE 802.1Q?

IEEE 802.1Q is the standard used for VLAN tagging. It adds VLAN information to Ethernet frames on trunk links.

+ Real-World Example (Office / Hospital)
  • VLAN 10 – Administration
  • VLAN 20 – Doctors / Staff
  • VLAN 30 – Laboratory Systems
  • VLAN 40 – Guest Wi-Fi