Virtual Extensible LAN
Virtual Extensible LAN is a network virtualization technology that attempts to address the scalability problems associated with large cloud computing deployments. It uses a VLAN-like encapsulation technique to encapsulate OSI layer 2 Ethernet frames within layer 4 UDP datagrams, using 4789 as the default IANA-assigned destination UDP port number. VXLAN endpoints, which terminate VXLAN tunnels and may be either virtual or physical switch ports, are known as VXLAN tunnel endpoints.
VXLAN is an evolution of efforts to standardize on an overlay encapsulation protocol. It increases scalability up to 16 million logical networks and allows for layer 2 adjacency across IP networks. Multicast or unicast with head-end replication is used to flood broadcast, unknown unicast, and multicast traffic.
The VXLAN specification was originally created by VMware, Arista Networks and Cisco. Other backers of the VXLAN technology include Huawei, Broadcom, Citrix, Pica8, Big Switch Networks, Cumulus Networks, Dell EMC, Ericsson, Mellanox, FreeBSD, OpenBSD, Red Hat, Joyent, and Juniper Networks.
VXLAN was officially documented by the IETF in RFC 7348. VXLAN uses the MAC-in-UDP packet encapsulation mode that restricts direct access to some of an object's components.
Open vSwitch is an example of a software-based virtual network switch that supports VXLAN overlay networks.
