VXLAN appears in modern network design scenarios as a way to extend segmentation across large environments without relying on traditional Layer 2 scaling limits. This episode introduces VXLAN as an overlay approach that carries Layer 2 segments over a Layer 3 underlay, enabling flexible placement of workloads while preserving logical separation. The first paragraph focuses on what overlays enable: large numbers of isolated segments, consistent segmentation across racks or sites, and the ability to support multi-tenant or multi-environment patterns without VLAN sprawl. It explains why architects use VXLAN when a design demands scale, mobility, and uniform behavior, and it emphasizes that the underlay must be stable and well-routed for the overlay to function reliably. The episode also frames VXLAN as a design tool for building predictable fabrics where segmentation and reachability can be expressed consistently even as physical topology grows.