Work on software-defined networking has been going on for almost two decades, but it’s only been in the past year that all of the pieces needed have been available to make a truly automated system.

But while a number of enterprises have downloaded versions of OpenFlow and other SDN components to play with there have been few software-defined networks put into production in organizations.

This week Gartner published a report for purchase studying some 30 deployments that showed increased agility, cost savings and/or improved security using SDN-based technologies. Four of those were detailed in the report including

–a U.S government agency using SDN to create a self-service development cloud;

–a consulting/services firm that needed to upgrade and expand its monitoring network in a cost-effective manner;

–a logistics company that wanted to reduce opex, enable multi-tenancy and improve agility

–and a regional bank that wanted to improve its intra-data-centre security.

In a blog Gartner’s Andrew Lerner gave away few secrets. But he did say the report estimates there are only between 500 and 1,000 mainstream deployments of SDN around the world.

Interestingly, roughly half of those studied use technology from vendors that are not in the top five in switching revenue, including NEC and VMware. (Other used solutions from Alcatel-Lucent, Cisco Systems Inc., Hewlett-Packard, Big Switch, Microsoft, Viptela, Plexxi and OpenDaylight.

Finally, the report concludes the biggest challenge SDN has to overcome has been organizational/cultural, not technology. SDN means that network control shifts to operations, which Lerner has been particularly difficult for network teams to accept.

As more vendors release case studies of enterprise implementations the case for when, where and how for SDN will be better made.