Does Rackspace use SDN to build its network in data centers

Rackspace have lunched a while ago cloud network product that provide the networking services as well as is the network infrastructure building block for the Openstack based cloud images. It can be pictured in this simple way like below.

But what vendor does Rackspace use to build its SDN based cloud network?

The cloud network at Rack is based on Nicira NVP product line. More info how we use and what it allows us to achieve can be found in the 'Nicira: Creating Virtual Networks in Cloud Data Centers' video.