In reply to John Lichnerowicz.

Thank you for the detailed response John! Wow, I really wish you could come to Cisco Live, as well - I'd love to sit down with you and discuss this further!

Your comments really highlight one of the most important issues when it comes to IoT security. As you correctly point out, there is no "one OT environment" ... rather, most OT environments are comprised of multiple disparate (and often proprietary) systems. Of course, where we may disagree is that they need to communicate with one another. That's not to say that there aren't cells or zones that need to be air gapped due to their sensitive operations or particularly high value, but to truly reap the benefits of IoT, most of the OT systems will need to converge to take advantage of the shared intelligence. Those OT systems will then need to be converged with IT systems for comprehensive end-to-end intelligence across the organization.

Of course, if you do all this, you need to take a radically different approach to security - and that was the point of this post.

Let's keep the discussion going ... I'd love to hear other perspectives, especially from the OT side of the house!