What are OT and IT Networks?

• IT (Information Technology) focuses on data: email, web, databases, business applications.

• OT (Operational Technology) focuses on physical devices: sensors, PLCs, SCADA, control

NETWORK TYPES USED IN OT/IT SYSTEMS

Both OT and IT can use wired and wireless connections, but the type, reliability, and security
requirements differ.

1. Ethernet (Wired Network - Most Common)

Used in IT & OT

• Speed: 100 Mbps to 10+ Gbps

• Medium: Twisted pair cable (Cat5e, Cat6), Fiber optics (for longer distance or EMI-prone areas)

• Protocols: TCP/IP in IT, Modbus TCP, Profinet in OT

Practical Execution:

1. Install Cabling: Use Cat6 or fiber optic cables depending on distance/interference.

2. Switch Configuration:

o Use managed switches for VLAN, QoS.

o Use industrial-grade switches for OT (shock, heat, dust resistant).

3. Device Setup:

o IP address assignment (Static for OT, Dynamic or Static for IT)

o Plug PLCs, HMIs, SCADA servers, PCs, printers into switches.

4. Testing:

o Ping tests, latency checks, bandwidth checks.

Virtual Execution (Simulation):

• Tools: Cisco Packet Tracer, GNS3, or VMware Workstation

• Simulate network topology: Switches, routers, PLCs (using virtual images or mock devices)

• Create VLANs, routing, and firewall rules to mimic real-world traffic

2. Wi-Fi (Wireless LAN)

Used mostly in IT, sometimes in OT (non-critical areas)

• Speed: 150 Mbps – 1+ Gbps

• Pros: No cable mess, easy to expand

• Cons: Signal interference, less secure, less deterministic (important for OT)

Practical Execution:

1. Install Access Points (APs) in office/warehouse

2. Secure Network: WPA3 encryption, SSID separation (Guest, Internal, OT)

3. Device Connection:

o Use industrial Wi-Fi bridges for OT devices (e.g., AGVs, mobile HMI panels)

o Use standard Wi-Fi cards for laptops/PCs

4. Monitor:

o Use wireless controllers or software like Ubiquiti Controller or Cisco DNA Center

Virtual Execution:

• Simulate wireless links in tools like EVE-NG, GNS3

• Use virtual firewalls and access points (OpenWRT in VM)

• Test packet loss, roaming scenarios

3. Fiber Optic

Used in both IT & OT where high speed or long distance is needed

• Speed: 1 Gbps – 100 Gbps

• Pros: Immune to EMI, long range (up to 40 km+)

• Cons: Expensive, fragile, needs trained installers

Practical Execution:

1. Install Fiber Cables between floors/buildings

2. Use SFP Modules in switches/routers

3. Test with OTDR for losses and breaks

• Simulate as Ethernet in virtual tools (functionally same in software)

• Add delay to mimic fiber latency if needed

4. Fieldbus / Serial Communication (for OT)

• Examples: Modbus RTU (RS-485), Profibus, CAN, HART

• Wired, real-time, used to communicate with sensors/PLCs

Practical Execution:

1. Connect devices using RS-485 serial cables

2. Set baud rate, parity, device ID

3. Configure PLC/SCADA to poll data

Virtual Execution:

• Simulate with tools like Factory I/O, Codesys, or PLCSIM Advanced

• Use virtual serial ports to simulate sensor data

5. Cellular (4G/5G for Remote OT)

• Used in OT for remote equipment (pipelines, substations)

• Devices have cellular modems with VPNs for security

Practical Execution:

1. Install SIM-enabled modem/router

2. Setup VPN tunnel to HQ or cloud

3. Route data to SCADA/Dashboard

Virtual Execution:

• Simulate cellular latency with WAN emulators

• Use virtual VPNs (WireGuard/OpenVPN) to test secure tunnel

6. Industrial Wireless Protocols

• Examples: WirelessHART, ISA100.11a, Zigbee, LoRaWAN

• Low power, reliable mesh for sensors/actuators

1. Deploy sensor nodes and gateways

2. Mesh setup auto-forms, configure via vendor software

3. Connect gateway to SCADA/Cloud

Virtual Execution:

• Simulate in MATLAB Simulink, NS-3, or vendor-specific tools

Integration of IT & OT Networks

• DMZ (Demilitarized Zone) used between OT and IT

• Use firewalls, NAT, and protocol converters

• Virtual networks: VLANs, SDN controllers

• Practical tools: Fortinet, Palo Alto, Cisco ASA

• Virtual tools: pfSense, GNS3, VMware NSX

Summary Table

Network Type IT OT Wired/Wireless Used For

Ethernet ✅✅ Wired Standard LAN

Wi-Fi ✅ (limited) Wireless Mobility, admin devices

Fiber Optic ✅✅ Wired Long distance, EMI-safe

Serial/Fieldbus ❌✅ Wired Sensor/PLC communication

Cellular (4G/5G) ✅ Wireless Remote OT connectivity

Industrial Wireless ❌ ✅ Wireless Sensor/actuator mesh

Would you like a visual network diagram showing how OT and IT connect with each other?