Industrial Networking

Industrial networking moves control and process data inside a plant under tougher constraints than office IT — deterministic timing, extreme temperatures, EMI, decade-long lifecycles, and zero tolerance for downtime.

Overview

Most modern installs are Ethernet-based, but a long tail of fieldbus (RS-485, CAN, etc.) and legacy serial remains. Network decisions should follow a documented architecture standard, not grow ad-hoc.

Purdue Model

• Level 0 — sensors, actuators.
• Level 1 — PLCs, RTUs, IEDs.
• Level 2 — HMI, SCADA, alarm.
• Level 3 — MES, historian, engineering.
• Level 3.5 (DMZ) — proxies, jump hosts.
• Levels 4–5 — enterprise IT, ERP.

Common Protocols

• EtherNet/IP (CIP) — Rockwell ecosystem.
• PROFINET — Siemens ecosystem.
• Modbus TCP / RTU — vendor-neutral, simple.
• EtherCAT — high-speed motion.
• OPC UA — cross-vendor data & modeling.
• MQTT Sparkplug B — IIoT pub/sub.
• BACnet, KNX, LON — building automation.
• DNP3, IEC 60870-5, IEC 61850 — utilities.

Topologies & Redundancy

• Star with managed switches — most common.
• Ring with RSTP, MRP (PROFINET), DLR (EtherNet/IP), or ERPS.
• Trunk + VLAN segmentation — separate control, video, IT.
• PRP / HSR (IEC 62439-3) for zero-failover utility networks.
• Redundant power supplies on critical switches.

Hardware

• Industrial managed switches: Cisco IE, Hirschmann, Stratix, Moxa, Phoenix Contact, Siemens Scalance.
• Firewalls/routers: Tofino, Hirschmann EAGLE, Cisco IE / ASA.
• Media converters & SFPs for fiber runs.
• Wireless: Cisco Industrial Wi-Fi, Phoenix Contact, Moxa AWK.

Cabling & Practice

• Cat 6/6A shielded (S/FTP) for industrial, M12 D/X-coded connectors.
• Multi-mode fiber OM3/OM4 for short runs; single-mode for long.
• Separate control cable from VFD/motor power; use proper grounding.
• Label every drop; maintain an as-built diagram.
• Document IP plan, VLANs, and protocols per cell/area.