DELL S6000-ON User Manual

Components of VXLAN Frame Format

Some of the important fields of the VXLAN frame format are described below:

Outer Ethernet 
Header:

The Outer Ethernet Header consists of the following components:

• Destination Address: Generally, it is a first hop router's MAC address when the 

VTEP is on a different address.

• Source Address : It is the source MAC address of the router that routes the 

packet.

• VLAN: It is optional in a VXLAN implementation and will be designated by an 

ethertype of 0×8100 and has an associated VLAN ID tag.

• Ethertype: It is set to 0×0800 because the payload packet is an IPv4 packet. 

The initial VXLAN draft does not include an IPv6 implementation, but it is 
planned for the next draft.

Outer IP 
Header:

The Outer IP Header consists of the following components:

• Protocol: It is set to 0×11 to indicate that the frame contains a UDP packet .
• Source IP: It is the IP address of originating VTEP.
• Destination IP: : It is the IP address of target VTEP.

Outer UDP 
Header: 

The Outer UDP Header consists of the following components:

• Source Port: Entropy of the inner frame. The entropy could be based on the 

Inner L2 header or Inner L3 header.

• VXLAN Port : IANA-assigned VXLAN Port (4789).
• UDP Checksum: The UDP checksum field is transmitted as zero. When a packet 

is received with a UDP checksum of zero, it is accepted for decapsulation.

VXLAN 
Header :

• VXLAN Flags : Reserved bits set to zero except bit 3, the first bit, which is set to 

1 for a valid VNI

1000

Virtual Extensible LAN (VXLAN)