IIC Journal of Innovation | Page 32

A Horizontal Taxonomy for the Industrial IoT architecture. That makes the task easier, but still non-trivial. The only way to do it is through experience. We are early on our quest. However, significant progress is within our collective grasp. This paper draws on extensive experience with nearly 1000 real-world IIoT applications. Our conclusion is that an IIoT taxonomy is not only possible, but critical to both individual system building and the inception of a true cross-industry Industrial Internet of Things. While the classification of IIoT systems is very early, we do suggests a few early divisions. To be as crisp as possible, we also chose numeric “metrics” for each division. The lines, of course, are not that stark. And, those lines evolve with technology over time at a much faster pace than biological evolution. Nonetheless, the numbers are critical to force clarity; without numerical metrics, meaning is often too fuzzy. 3.1 Reliability Metric: Continuous availability must exceed “99.999%” to avoid severe consequences Architectural Impact: Redundancy Many systems describe their requirements as “highly reliable” or “mission critical” or “minimal downtime”. However, those labels are often more platitudes than actionable system requirements. To be meaningful, we must be more specific about the reasons we must achieve that reliability. That requires understanding of how quickly a failure causes problems and how bad those problems are. IIC Journal of Innovation - 31 -