VXLAN & OSI Layers

[Ringhio_Reinard]

Hello Group,

I keep reading that VXLAN is a Layer 2 technology but somehow it does not click.
According to Cisco VXLAN "... encapsulates Ethernet frames into IP User Data Protocol (UDP) headers and transports the encapsulated packets through the underlay network to the remote VTEPs using the normal IP routing and forwarding mechanism." ( www.cisco.com/c...c11-732453.html ).
That seems more like a layer above 4 as the UDP segment encapsulates the upper layer, the VXLAN "Frame", which in turn encapsulates the original Ethernet frame.
That would explain how VXLAN can leverage standard L2 and L3 network appliances.

Regards
DR

[Luke Hoffer]

You're correct that the VXLAN protocol itself operates a little further up the stack.  When people refer to it as a L2 technology, they're really referring to its inherent ability to encapsulate L2 traffic so that it can be forwarded across L3 boundaries to essentially decouple the L2 domain from the underlying physical infrastructure.  Assuming that the infrastructure can accommodate the slight uptick in MTU size to accommodate the encapsulation overhead (VMware NSX requires at least a 1600 byte MTU), then the use of VXLAN is transparent to the physical infrastructure as the encapsulated traffic is just normal UDP/IP traffic.