VXLAN
VXLAN (Virtual Extensible LAN) is a network virtualization technology that creates layer 2 overlay networks on top of layer 3 infrastructure, using MAC-in-UDP encapsulation. It extends VLAN scalability by providing a 24-bit segment ID (VXLAN Network Identifier or VNI) that supports up to 16 million logical networks, compared to VLAN's 4094 limit. VXLAN is commonly used in data centers and cloud environments to enable multi-tenancy, workload mobility, and network segmentation across physical boundaries.
Developers should learn VXLAN when working in large-scale cloud, data center, or virtualized environments where traditional VLANs are insufficient due to scalability limitations or when needing to span layer 2 networks across layer 3 boundaries. It's essential for implementing software-defined networking (SDN), network virtualization, and microsegmentation in modern infrastructure, particularly with technologies like VMware NSX, Cisco ACI, or open-source solutions like Open vSwitch.