That result chimes with our own informal investigations, which is why we've done a series of explanatory videos and featured a lengthy "Intelligent Person's Guide" to SDN. And we are preparing some more research questions which we'll be asking you for help on soon.

According to the Tail-f survey, more than 200 large US companies judge SDN to be the most important current technology initiative - eclipsing cloud (that was 3 years ago), and virtualisation (10 years ago). When presented with a list of five different IT initiatives, 87 percent of respondents chose SDN as important.

Most respondents (92 per cent) rate their understanding of SDN as pretty good or even complete; yet only about half (51 per cent) chose a correct definition of SDN, says Tail-f (though whether all the other experts would agree with Tail-f's 'correct' version might be a discussion worth having).

The SDN confusion is not surprising. One month it appeared to be a rather futuristic concept, inevitable later rather than sooner. The next month SDN was suddenly a done deal and just around the corner. As a result many people in our industry are not so much confused, but not quite fully up to speed. They understand why SDN is a good idea and they can see its broad implications. But beyond that, a wealth of detail is still missing.