Episode 30 — VLAN Segmentation: what it solves and common design traps
VLANs remain a common segmentation mechanism in campus and data center scenarios, and this episode explains what VLAN segmentation solves and where it commonly goes wrong. It defines VLANs as a way to separate broadcast domains at Layer 2 while allowing shared physical infrastructure, and it explains how VLANs support organizational separation, reduce unnecessary broadcast traffic, and establish boundaries that can be enforced with routing and policy. The first paragraph focuses on the relationship between VLANs, trunking, tagging, and inter-VLAN routing, explaining that VLAN separation alone does not create security unless policies are enforced at the routing boundary or through additional controls. It also explains why VLAN design must align to roles, trust levels, and operational ownership rather than being created ad hoc, because unmanaged VLAN sprawl becomes difficult to secure and troubleshoot.
