VMware has a technology problem. It's backing two competing standards for overlay networks: Nicira's STT and the IETF draft standard VXLAN. An overlay network enables network virtualization, which is a core component of VMware's software-defined data center initiative. Both STT and VXLAN have upsides and downsides. I'll look at each protocol and speculate on which direction VMware may go.

First, a little background. Before being acquired by VMware, Nicira developed the Stateless Transport Tunneling (STT) protocol for tunneling between open source software switches in the Openvswitch project.

VXLAN, which is now an IETF draft standard, was originally proposed by Cisco. Cisco sources say that the company then got VMware involved (although the IETF draft has a lot of names on it). The end result is VMware is telling everyone that it has this great VXLAN overlay network technology that removes any hypervisor dependency from physical network devices. Even better, it's configured and managed from vCenter.

The question is, which protocol will win?