2
Figure 1 VXLAN network model
VXLAN packet format
As shown in
, 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