Should You Segment Your Control Network?

As manufacturing facilities become increasingly digitized, there’s a growing emphasis on designing systems that aren’t just reliable, but also resilient. The decision to segment control networks — splitting systems into isolated zones rather than running everything on a single network — has become one of the most debated topics in industrial automation. Plant managers and IT professionals find themselves weighing security benefits against operational complexity, often without clear guidance on what works best for their specific situation.

The stakes are high. A well-designed network architecture protects against cyber threats while maintaining the seamless communication that modern manufacturing demands. Get it wrong, and facilities risk everything from production delays to security breaches that can shut down operations for weeks.

What is network segmentation?

Network segmentation creates separate zones within manufacturing systems, isolating different types of equipment and functions. Instead of connecting SCADA systems, human-machine interfaces, programmable logic controllers, and safety systems to one large network, segmentation puts them in distinct network areas with controlled communication paths between zones.

Think of it like building walls with doorways. A packaging line might operate in one segment, while quality control systems run in another. The segments can still communicate when needed, but they’re protected from problems that occur in other areas. This differs dramatically from flat network architecture, where a single network cable connects all devices and systems sharing the same digital space.

Segmentation typically involves physical separation using different switches and routers, virtual separation through VLANs, or a combination of both approaches. The goal is creating boundaries that limit how problems spread while maintaining necessary system integration.

The security argument for segmentation

Cybersecurity drives much of the interest in network segmentation. Manufacturing facilities face increasingly sophisticated attacks. Segmentation provides multiple layers of defense that flat networks simply can’t match. By isolating systems, manufacturers can:

• Contain security breaches: When attackers compromise one system, segmentation prevents them from automatically accessing everything else on the network. A compromised office computer can’t reach production systems with proper safeguards in place.
• Protect legacy systems: Many control systems lack built-in security features and can’t be updated easily. Segmentation creates protective barriers around these vulnerable devices, reducing their exposure to threats.
• Air-gap security for sensitive operations: Air-gapping completely disconnects sensitive systems from external networks. This provides maximum security but can complicate remote monitoring and data collection.
• Maintain regulatory compliance: Highly regulated industries face strict requirements for data integrity and system security. Segmentation helps meet these standards by creating documented security zones with controlled access.

Performance and operational trade-offs

Should you segment your control network? That depends. Segmentation creates both benefits and challenges for daily operations. The impact varies depending on how facilities implement and manage their segmented architecture:

• Performance: Segmentation can improve network performance by reducing traffic congestion. For example, when packaging equipment communicates only with related systems instead of sharing bandwidth with the entire facility, response times improve and network bottlenecks decrease.
• Complexity: Troubleshooting becomes more complex when technicians must understand multiple network segments and their interconnections. Maintenance tasks that once required accessing a single network now involve navigating between different zones, each with its own access controls and procedures.
• Integration: Modern manufacturing relies on data flowing between systems for optimization and reporting. Segmented networks need carefully designed communication paths that maintain security while enabling necessary data exchange. This often requires additional hardware, software, and ongoing management.

Should you segment your control network?

Network segmentation is a shift from convenience to intentional design. While flat networks feel simpler, they trade short-term ease for long-term vulnerability. The question isn’t whether segmentation adds complexity — it does. The question is whether that complexity is worth the protection it provides when a single breach could cost millions in downtime and recovery. For most, it does.