DNP3 Network Design for Pipeline SCADA

Quick Answer

Pipeline DNP3 SCADA networks typically use licensed radio (900MHz/UHF) for field sites, cellular for remote locations, and Ethernet for control centers. Design considerations include radio coverage, polling cycle time, bandwidth utilization, redundant communication paths, and cybersecurity.

Communication Media

• Licensed radio — 900MHz or UHF narrowband. Point-to-multipoint from central tower. Most common for pipeline SCADA in oilfield areas with radio infrastructure.
• Cellular (4G LTE) — For remote sites without radio coverage. Higher ongoing cost but no infrastructure investment.
• Satellite (VSAT, Iridium) — For extremely remote sites. High latency, limited bandwidth.
• Fiber/Ethernet — For control center to SCADA server connections and co-located equipment.

Polling Schedule Design

• Integrity poll: every 15-30 minutes (full data sync)
• Class 1 (alarms): every 2-5 seconds
• Class 2 (process): every 5-30 seconds
• Class 3 (status): every 30-120 seconds
• Enable unsolicited for critical alarms on all outstations

Bandwidth Planning

At 9600 baud with 50 outstations, each integrity poll generates significant traffic. Use event-based reporting (Classes 1-3 with deadband) as the primary data exchange, with infrequent integrity polls for synchronization only.

Redundancy

• Dual communication paths (radio + cellular) with automatic failover
• Redundant SCADA masters with hot-standby
• Store-and-forward on outstations during communication outages

Security

Use Secure Authentication for control commands. VPN for DNP3/TCP over cellular. Physical security for radio infrastructure. See OT cybersecurity for network segmentation practices.