Version 4.1 - 6.5.b VXLAN
VXLAN is a technology which allows overlaying a Layer 2 (L2) network over a Layer 3 (L3) underlay with use of any IP routing protocol. It uses MAC-in-UDP Encapsulation.
VXLAN (Virtual Extensible LAN) - The technology that provides the same Ethernet Layer 2 network services as VLAN does today, but with greater extensibility and flexibility.
VNID (Vxlan Network Identifier) - 24 bit segment ID that defines the broadcast domain. Interchangeable with "VXLAN Segment ID".
VTEP (Virtual Tunnel Endpoint) - This is the device that does the encapsulation and de-encapsulation.
NVE (Network Virtual Interface) - Logical interface where the encapsulation and de-encapsulation occur.
Now this is a topic that I don't have a lot of experience with, so I'm using the Configure VXLAN page in the Configuration Examples and TechNotes for this section.
There is also a White Paper - VXLAN Overview that is quite thorough.
VXLANs are covered in RFC 7348. The RFC outlines the problem that VXLANs were created to solve and Security concerns.
IANA has assigned the value 4789 for the VXLAN UDP port, and this value SHOULD be used by default as the destination UDP port. When calculating the UDP source port number using a hash of fields from the inner packet, it is RECOMMENDED that the value be in the dynamic/private port range 49152-65535.