Vxlan Frame Format; Components Of Vxlan Frame Format - Dell S4048–ON Configuration Manual

• VXLAN communicates with the VTEP using a standard protocol called OvsDb Protocol. The protocol uses the JSON RPC-
based message format.
• The VTEP acts according to the TOR schema defined by VMWare. The solution is very specific to VMWare-based
orchestration platforms and does not work with other orchestration platforms.

VXLAN Frame Format

VXLAN provides a mechanism to extend an L2 network over an L3 network. In short, VXLAN is an L2 overlay scheme over an L3
network and this overlay is termed as a VXLAN segment. VMs within the same VXLAN segment communicate with each other
through a 24–bit ID called VXLAN Network Identifier (VNI). This 24–bit ID allows up to 16 million VXLAN segments to coexist within
the same administrative domain. The VNI scopes the inner MAC frame originated by the VM. This model has over-lapping MAC
addresses without traffic cross-over
VXLAN achieves L2 over L3 overlay using the tunneling mechanism. VTEPs are the end points of a tunnel located within the
hypervisor on the server that hosts VMs. The VXLAN frame format is shown in the following figure:
Figure 147. VXLAN Frame Format

Components of VXLAN Frame Format

Some of the important fields of the VXLAN frame format are described below:
Outer Ethernet The Outer Ethernet Header consists of the following components:
Header:
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Outer IP Header: The Outer IP Header consists of the following components:
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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.
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.
Virtual Extensible LAN (VXLAN)
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