VXLAN

VXLAN extends layer 2 networks over layer 3 infrastructure by encapsulating Ethernet frames in UDP, and it is the backbone of network virtualization in modern data centers and clouds. It supports about 16 million virtual segments versus the 4096 limit of traditional VLANs. The encapsulation has no built-in authentication or encryption, so a host that can inject VXLAN packets may spoof traffic into other tenants' segments, making underlay access control critical.