VXLAN packet format
As shown in Figure 2, a VTEP encapsulates a frame in the following headers:
8-byte VXLAN header—VXLAN information for the frame.
Flags—If the I bit is 1, the VXLAN ID is valid. If the I bit is 0, the VXLAN ID is invalid. All other bits are reserved and set to 0.
24-bit VXLAN ID—Identifies the VXLAN of the frame. It is also called the virtual network identifier (VNI).
8-byte outer UDP header for VXLAN—The default VXLAN destination UDP port number is 4789.
20-byte outer IP header—Valid addresses of VTEPs or VXLAN multicast groups on the transport network. Devices in the transport network forward VXLAN packets based on the outer IP header.
Figure 2: VXLAN packet format
