Definition
VXLAN, or Virtual eXtensible LAN, is a network virtualization technology that creates virtual Layer 2 networks on top of an existing Layer 3 infrastructure. It achieves this by encapsulating Layer 2 Ethernet frames within Layer 3 UDP packets, allowing for the extension of Layer 2 segments across geographically dispersed data centers or cloud environments. This encapsulation process effectively masks the underlying IP network, enabling the creation of isolated and scalable virtual networks. VXLAN is crucial for modern data centers and cloud deployments, providing the flexibility to segment tenant traffic and manage large numbers of virtual machines without being constrained by physical network topology. For instance, cloud providers use VXLAN to offer isolated virtual networks to their customers, ensuring security and resource segregation. It is distinct from VLANs, which are limited to a single broadcast domain and a maximum of 4094 IDs, whereas VXLAN supports over 16 million segments. Understanding VXLAN is beneficial for roles involving network architecture and cloud security, appearing on certifications like CISSP and CCSP.