Components of VXLAN Frame FormatSome of the important fields of the VXLAN frame format are described below:Outer EthernetHeader: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 anassociated VLAN ID tag.• Ethertype: It is set to 0×0800 because the payload packet is an IPv4 packet. The initial VXLAN draft does notinclude 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 L3header.• VXLAN Port : IANA-assigned VXLAN Port (4789).• UDP Checksum: The UDP checksum field is transmitted as zero. When a packet is received with a UDPchecksum 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• VNI: The 24-bit field that is the VXLAN Network Identifier• Reserved: A set of fields, 24 bits and 8 bits, that are reserved and set to zero .Frame CheckSequence (FCS):Note that the original Ethernet frame's FCS is not included, but new FCS is generated on the outer Ethernetframe.Configuring and Controlling VXLAN from the NVPController GUIYou can configure and control VXLAN from the NVP controller GUI, by adding a hardware device to NSX and authenticating the device.1 Generate a certificate in your system and add it to the NSX before adding a hardware device for authentication.To generate a certificate, use the following command:• crypto cert generate self-signed cert-file flash://vtep-cert.pem key-file flash://vtep-privkey.pemVirtual Extensible LAN (VXLAN) 997
