I was recently asked to investigate two OT / SCADA networks one plant network supporting distributed SCADA /PLC and a second 8 node control network linking PLC to RIO. The network system was suffering from unpredictable network behaviour that had impacted operation - never a great selling point for a new SCADA deployment!
I have specified more automation network solutions over the years than most and have delivered network infrastructure into virtually every industry. There does seem to be one constant in recent times and it relates to ownership of matters relating to Network and Cyber Security
This is a subject I am passionate about (sad I know). My feeling is that what we see today, while undesirable, is a foreseen consequence of industry standardizing on open technologies for distributed control and SCADA networks. Don't get me wrong I believe Ethernet is great technology and when deployed as a 'network' rather than simply 'connectivity' it can provide much gain with controlled amount of pain. What has happened in many cases over the years is somewhat different.