H3C Technologies H3C S12500-X Series Switches - Manual (Page 9)

2
Figure 1 VXLAN network model
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 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