OT/IT Segmentation Calculators
Chapter 9 — Five interactive real-time calculators for firewall sizing, bandwidth planning, DMZ zone design, compliance scoring, and security ROI analysis
Calculator 1: Industrial Firewall Throughput Sizing
Determine the minimum required firewall throughput for your OT/IT boundary based on the number of OT devices, traffic profiles, and inspection requirements. Results include recommended throughput with DPI enabled, HA overhead, and headroom margin.
Calculator 2: DMZ Zone Bandwidth Planner
Plan the bandwidth allocation across all DMZ service channels: Historian replication, patch delivery, remote access, log forwarding, and NTP/DNS. Visualize the bandwidth distribution as a real-time pipe diagram and identify potential bottlenecks.
Calculator 3: Security Zone Design & Firewall Rule Estimator
Estimate the number of firewall rules, security zones, and DMZ services required based on your OT environment characteristics. The calculator also generates a recommended zone structure and rule count breakdown.
Calculator 4: OT Security Compliance Score
Assess your OT/IT segmentation design against key compliance frameworks: IEC 62443, NIST SP 800-82, NERC CIP, and ISA-99. Adjust the sliders to reflect your current implementation level and see your compliance score in real time.
Calculator 5: OT Security Investment ROI Calculator
Calculate the return on investment for your OT/IT segmentation project by comparing the estimated cost of a cyber incident against the cost of implementing the segmentation solution. The calculator uses industry-average incident cost data and your specific operational parameters.