OT Network Architecture
We design secure OT network architectures that prevent lateral movement, protects critical assets, and enables safe IT/OT convergence.
Your Flat Network Is an Open Highway for Attackers
When IT and OT converge without proper segmentation, a single compromised laptop can reach your production controllers in minutes. Legacy architectures designed for air-gapped isolation cannot protect modern, connected industrial environments.
IT/OT Convergence Creates Massive Security Gaps
Your production environment needs connectivity to IT for efficiency gains – remote monitoring, data analytics, predictive maintenance. But connectivity without architectural security transforms your OT network into a target-rich environment.
Flat networks enable lateral movement. Without segmentation, attackers who compromise a single device can move freely through your entire network. A compromised engineering workstation becomes a direct path to PLCs and SCADA systems.
The air gap is a myth. Research consistently shows that industrial networks have numerous undocumented connections to IT networks – despite claims of air-gapped isolation. Your production network is already connected. The question is whether those connections are secured.
Breaches in OT are operational disasters. When attackers reach production systems, the impact isn't stolen data – it's stopped production lines, compromised product quality, safety incidents. A manufacturer's production shutdown costs millions per day.
The result: Security incidents cascade from entry point to production systems. Compliance audits reveal architectural gaps you cannot quickly remediate. Digital transformation initiatives stall because you cannot securely connect new technologies to existing flat networks.
Defense-in-Depth Architecture That Contains Threats Before They Reach Production
BxC designs OT network architectures that protect critical assets through layered defense. We implement proven models like Purdue/ISA-95 or IEC 62443, adapted to your operational reality – not textbook theory, but architectures that work with your legacy equipment, operational constraints, and business requirements.
Zone and conduit segmentation
We group assets by security requirements into protected zones – separating physical processes (Level 0) from site operations (Level 3) from enterprise networks (Level 4-5). Controlled conduits between zones enforce "deny by default" policies.
Industrial DMZ as the IT/OT bridge
Rather than direct IT/OT connections, we establish a demilitarized zone with historians, application servers, and jump hosts that mediate all cross-boundary traffic. This enables operational efficiency while preventing direct attack paths.
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Pragmatic approach for brownfield environments
We design architectures that work with your existing infrastructure. We identify practical improvement paths for brownfield environments – starting with high-risk areas, phasing implementation to align with maintenance windows.
Three Phases from Assessment to Protected Production
1. Network Assessment Phase
We evaluate your existing network security posture: gathering site-specific information, conducting stakeholder interviews with operations and IT teams, evaluating existing security measures, reviewing architecture documentation, identifying critical communication flows, and analyzing compliance gaps against IEC 62443, NIS2, or industry-specific requirements.
2. Network Design Phase
Based on assessment findings and your business objectives, we develop comprehensive network architecture design: defining security zones based on asset criticality, establishing conduits with documented trust relationships and firewall rules, designing Industrial DMZ architecture, specifying network access controls, planning monitoring points, and documenting migration approach for brownfield environments.
3. Implementation Coordination
We coordinate deployment of your secure network architecture: project management, working with your IT/OT teams and network vendors, phased implementation starting with highest-risk segments, testing security measures before production deployment, validation of operational workflows, training stakeholders to operate in segmented environments, and documentation and knowledge transfer.
Protecting Global Manufacturing Sites
A leading global pharmaceutical organization required comprehensive network redesign across multiple manufacturing sites – established production networks with legacy architectures, now needing security-by-design to meet regulatory requirements.
BxC's team developed secure network architecture following IEC 62443 principles and industry best practices. The engagement required coordinating with site operations, IT teams, and global security across multiple countries; designing zone and conduit architecture adapted to pharmaceutical manufacturing; establishing Industrial DMZ infrastructure; and creating phased implementation roadmap aligned with production schedules.
The architecture was deployed across all sites over a multi-year program. The result: documented, compliant network segmentation that protects critical manufacturing systems while supporting business requirements.
This is the scale and complexity we navigate daily. Brownfield environments. Global coordination. Regulatory compliance. Zero production disruption.
Network Architecture That Delivers Measurable Security and Operational Outcomes
Segmented architectures stop attacks at zone boundaries. A compromised engineering laptop cannot reach production controllers across DMZ firewalls. Breaches are contained to the entry point, preventing organization-wide impact. Defense-in-depth provides detection and response time before attackers reach critical assets.
Network segmentation, when designed correctly, does not obstruct operations – it enables them. Secure remote access for vendors, controlled data flow to business systems, and monitored connectivity support efficiency without introducing uncontrolled risk. Operational workflows remain functional within the secure architecture.
IEC 62443, NIS2, KRITIS, and industry-specific regulations require documented network segmentation, zone-based controls, and managed conduits. Our architectures are designed from the start to meet these requirements. Compliance becomes straightforward when security is built into the architecture rather than retrofitted.
Flat networks become increasingly difficult to secure as you add connected devices, cloud integrations, and IIoT sensors. Segmented architecture provides the foundation for safe digital transformation. New technologies can be integrated into appropriate zones with defined security controls rather than creating uncontrolled connections across flat networks.
Controlled conduits between zones become monitoring points. Network architecture defines where to implement detection, logging, and anomaly detection systems. You cannot secure what you cannot see – segmentation creates the structure for operational visibility.
Our network architecture engagements complement your broader cybersecurity program. We coordinate with your existing security initiatives and vendor relationships.
OT Network Architecture establishes the foundational security layer. Complement with:
- Cybersecurity Assessment to identify current state and gaps
- PKI Consulting to implement identity and authentication across zones
- Privileged Access Management to control administrative access through DMZ
- Cybersecurity Architecture Advisory for defense-in-depth security architecture
- Implementation Coordination for large-scale deployment programs
Concrete Deliverables Protect Your Production
Architecture Design Package
Comprehensive network architecture documentation with zone definitions, conduit specifications, firewall rule sets, and security justifications. Ready for implementation and audit.
Implementation Roadmap
Phased deployment plan aligned with your capital cycles, maintenance windows, and operational constraints. Prioritized by risk and feasibility.
Regulatory Compliance Documentation
Architecture documentation that supports IEC 62443, NIS2, KRITIS compliance. Includes zone/conduit specifications and security controls mapping required for audits.
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Knowledge Transfer
Your teams understand the architecture, can operate it, and can explain it to auditors. We don't create dependency – we build capability.
Industries and Scenarios Where We Deliver Impact
- Pharmaceutical Manufacturing: GMP-compliant network segmentation across global sites. FDA 21 CFR Part 11 and EU GMP Annex 11 requirements. Protecting batch integrity and product quality data.
- Chemical Plants: CFATS compliance and critical infrastructure protection. Safety-instrumented systems (SIS) network isolation. Hazardous process control security.
- Energy Sector: NERC CIP compliance for bulk electric systems. SCADA network protection. Renewable energy control system security.
- Discrete Manufacturing: Automotive or consumer goods. Protecting production lines, robotics, and quality systems. Industry 4.0 security architecture.
You need us if: Your OT network is flat or poorly segmented | You're connecting production to IT/cloud | You face NIS2, IEC 62443, or KRITIS compliance | You've had security incidents or near-misses | You're building new facilities or modernizing existing ones
From Initial Assessment to Secure Architecture
You need to understand what an OT network architecture engagement involves – timeline, resources, and your team's involvement.
- Assessment: 2-6 weeks: Documentation review, stakeholder interviews, on-site evaluation, analysis. You receive detailed assessment report with findings and preliminary recommendations.
- Design: 1-4 months: Comprehensive architecture design, zone/conduit specifications, implementation roadmap. Fixed-price engagement with clear deliverables.
- Implementation: 6 months to 2+ years: Varies by scope and operational constrainst Single-site focused projects: 6-12 months. Global programs across 20+ sites: 18-36 months. We recommend pilot implementations before scaling.
- Investment: Network architecture engagements are scoped as fixed-price projects based on number of sites, assessment depth, and design complexity. After initial discussion, we provide detailed proposal. Assessment, design, and implementation can be separate engagements or phased programs.
Who needs to be involved: OT teams, IT/network teams, security organization. BxC engineers work alongside your teams – we provide expertise in secure OT architecture while your teams contribute operational knowledge.
Not sure if your network
needs redesign?
Our Cybersecurity Assessment Service evaluates your overall security posture and helps prioritize investments.
Grounded in Industry Standards, Adapted to Operational Reality
BxC's network architecture designs are grounded in industry frameworks while adapted to your operational constraints.
Architecture & Standards
Purdue Model / ISA-95 – Foundation for zone-based OT network segmentation
IEC 62443-3-2 – Security levels for zones and conduits
Defense in Depth – Layered security controls across network architecture
Industrial DMZ – Controlled IT/OT boundary replacing air gaps
VLAN segmentation – Network layer separation within zones
Firewall architectures – Perimeter, zone, and micro-segmentation firewalls
Zero Trust principles – "Never trust, always verify" adapted for OT environments
Network monitoring integration – Architecture designed for visibility and detection
Compliance & Regulations
IEC 62443 – International standard for industrial cybersecurity. Our architectures implement network segmentation and zone/conduit requirements (IEC 62443-3-2) plus system-level requirements (IEC 62443-3-3).
NIS2 Directive – EU cybersecurity regulation for critical infrastructure. Our designs meet NIS2 requirements for network segmentation, security controls, and incident containment.
KRITIS – German critical infrastructure regulations. Network architecture supports KRITIS compliance requirements for sectors like energy, water, and healthcare.
Industry-specific regulations – Pharmaceutical (FDA 21 CFR Part 11, EU GMP Annex 11), Chemical (CFATS), Energy (NERC CIP). Architectures designed for sector-specific compliance.
Audit readiness – Deliverables include architecture documentation, zone/conduit specs, firewall rules, and security justifications for audits and compliance validation.
Brownfield and legacy support
We design architectures that work with existing infrastructure. Not every plant can implement full Purdue model immediately. We identify pragmatic migration paths that improve security incrementally while respecting capital constraints and operational limitations.
OT Security Specialists, Not Generalists
- Two decades of OT security expertise. BxC specializes in IT-OT convergence and industrial cybersecurity. We understand operational constraints, brownfield limitations, and the balance between security and production requirements.
- Deep knowledge of industrial protocols. We design networks for OT realities – legacy devices with limited security capabilities, deterministic control requirements, vendor access needs, 24/7 production schedules.
- Proven in regulated industries. Our network designs meet requirements of NIS2, IEC 62443, KRITIS in pharmaceutical, chemical, energy, and manufacturing sectors where compliance, safety, and uptime are non-negotiable.
- Vendor-neutral consulting. We're not tied to specific firewall vendors or network equipment manufacturers. Our recommendations are based on your requirements and existing infrastructure, not vendor commissions.
Frequently Asked Questions
Got questions? We’ve got answers. Here are some common queries about OT Network Architecture.
Properly designed and phased implementation minimizes operational disruption. We coordinate with production schedules, implement changes during maintenance windows, and thoroughly test configurations before production deployment. Our team has experience implementing segmentation in 24/7 manufacturing environments.
Yes. BxC specializes in brownfield environments with legacy controllers, HMIs, and SCADA systems that lack modern security capabilities. Network architecture provides the security layer these devices cannot provide themselves. We design solutions that work with your existing equipment while creating migration paths for future modernization.
OT networks have fundamentally different requirements – deterministic control, real-time constraints, protocol-specific needs, safety implications, 24/7 availability. BxC brings specialized OT security expertise combined with understanding of industrial operations. We work alongside your IT teams, bringing the OT-specific knowledge required for production environments.
Investment depends on environment complexity, number of sites, and implementation scope. Single-site assessment and design: typically mid-five to low-six figures. Multi-site global programs: scale accordingly. After initial discussion, we provide detailed proposals with phased approach and clear deliverables.
Start with a network security assessment to understand your current state, identify highest-priority gaps, and develop a phased approach. Many organizations begin with high-risk segments or single sites rather than enterprise-wide programs. Assessment provides the roadmap – you control implementation pace.