Why It Matters

Whether you’re working in IT support, system administration, or cybersecurity, having a solid grasp of network segmentation and subnetting is essential. These concepts form the backbone of modern network design and are critical for building secure, scalable, and high-performance environments.

Knowing how to segment a network properly allows you to:

• Control and limit access between departments (e.g., finance and HR)
• Isolate sensitive devices or servers from the rest of the network
• Reduce the spread of malware or unauthorized traffic in case of a breach
• Optimize network performance by minimizing unnecessary broadcast traffic

You’ll often apply this knowledge in real-world scenarios such as:

Understanding VLANs: Virtual Local Area Networks

What is a VLAN?

A Virtual Local Area Network (VLAN) is a method of network segmentation that creates isolated logical networks within a physical switch. Unlike traditional LANs, which rely on physical topology to group devices together, VLANs provide virtualized segmentation, allowing network administrators to define communication boundaries without being restricted by physical connections.

Each VLAN functions as an independent network, meaning devices within the same VLAN can communicate directly, while communication between different VLANs requires a Layer 3 device (router or Layer 3 switch). This logical separation improves security, performance, and network management.