Reference Architecture Diagram + Narrative (SCADA-grade resiliency)
┌──────────────────────────────────────────────┐
│ ROLES & ZONES │
Control Center Ops │ OT/SCADA Eng │ Field Crews │ Market Ops │ IT/Sec │
└───────────┬─────────────┬───────────┬────────┘
│ │ │
▼ ▼ ▼
┌────────────────────────────────────────────────────────────┐
│ GRID EDGE / SITES (GEN, SUBSTATIONS, DER, AMI) │
│ ▸ RTUs / IEDs / PLCs / Relays │
│ ▸ AMI head-ends, DER inverters, microgrids │
├────────────────────────────────────────────────────────────┤
│ OT GATEWAYS / DATA DIODE / LOCAL HISTORIAN (store&forward) │
│ SD-Branch / SD-WAN EDGE | VRFs: OT | IT | Vendor | Guest │
│ Private 5G/LTE (plant yards) | NAC/NGFW | ZTP templates │
└───────────────┬──────────────────────────────┬──────────────┘
│ │
Licensed Microwave / MPLS / DIA backhaul │ LTE/5G FWA (field)
│ │ SATCOM (remote/DR)
▼ ▼
┌────────────────────────────────────────────────┐
│ TRANSPORT / SECURITY FABRIC │
│ SD-WAN overlays ║ MPLS ║ Waves ║ IX/Peering │
│ SASE/SSE POPs: ZTNA | SWG | CASB | FWaaS | DLP│
│ (geo/data-sovereignty fences; vendor gating) │
└──────────────┬───────────────────┬─────────────┘
│ │
▼ ▼
┌───────────────────────────────────┐ ┌────────────────────────────┐
│ UTILITY CORES (Control Centers) │ │ CLOUD ON-RAMPS │
│ • EMS/DMS/ADMS • Outage Mgmt │ │ Analytics | Forecasting │
│ • SCADA Masters • Historian │ │ Market Ops | Data Lake │
│ • IdP/PAM • HSM/KMS • SIEM/NDR │ │ (private DX/ER/GCI) │
└──────────────┬────────────────────┘ └──────────────┬─────────────┘
│ │
▼ ▼
┌──────────────────────────────┐ ┌────────────────────────┐
│ MARKET / ENTERPRISE APPS │ │ MOBILE WORKFORCE APPS │
│ Trading, CIS/Billing, GIS │ │ Crew dispatch, AR/VR │
└──────────────────────────────┘ └────────────────────────┘
Observability & Compliance Bus ───────► NOC/SOC + AIOps + ITSM/CMDB + NERC-CIP Audit Vault
Narrative (keeping the grid coherent under stress)
1) Purpose & posture
- Objective: Provide mission-critical, sovereign connectivity for generation plants, substations, DER/AMI, and control centers with deterministic SCADA performance and regulatory assurance.
- Posture: Zero-Trust + Defense-in-Depth, with OT/IT segmentation, vendor access gating, and data-sovereignty enforcement.
2) Edge & transport (syntax where reliability matters)
- Site edge: SD-Branch/SD-WAN with VRFs for OT / IT / Vendor / Guest. OT gateways normalize protocols (DNP3/IEC-60870-5/IEC-61850/Modbus), with local historian + store-and-forward. Optional data diode for one-way telemetry.
- Underlays: Licensed microwave / MPLS / DIA as primary backhaul; LTE/5G FWA for field ops; SATCOM for isolated sites and DR. Private 5G can blanket plants/yards for mobile OT devices.
3) Security fabric (semantics preserved)
- SASE/SSE POPs apply ZTNA (role/device/time/geofence), SWG/CASB/FWaaS/DLP for IT/SaaS flows, and vendor access windows via PAM.
- Microsegmentation prevents lateral movement between OT cells; NDR (OT-aware) inspects east-west patterns for anomalies.
4) Control centers & cloud (where meaning aggregates)
- Utility cores host SCADA masters, EMS/DMS/ADMS, outage management, historian, IdP/PAM, HSM/KMS, SIEM/NDR, and immutable audit vaults for NERC-CIP.
- Cloud on-ramps (Direct Connect/ExpressRoute/Interconnect) provide private access to analytics (load/price forecasting), data lakes, and market operations with pinned regions.
5) Resilience patterns (grammar under stress)
- Automatic failover: SD-WAN steers SCADA to secondary microwave/MPLS; if terrestrial fails, LTE/SATCOM carries critical telemetry/commands.
- Data continuity: Local historian buffers telemetry; upon recovery, ordered replay ensures historian integrity.
- DER & AMI: Head-end systems aggregate securely; microgrids can island with local control if backhaul is impaired.
6) Ops & compliance (pragmatics)
- AIOps observability correlates link health, SCADA latency, DER/AMI volumes; proactive maintenance tickets in ITSM/CMDB.
- NERC-CIP evidence (access logs, configuration baselines, immutable records) is continuously collected for audit; vendor sessions are just-in-time and recorded.
7) Reference KPIs (utility-grade)
- SCADA command latency: < 50 ms substation↔control (design target).
- Availability: ≥ 99.99% backbone; Failover: < 60 s.
- Telemetry completeness: > 99.5% during incidents (via buffering).
- MTTD/MTTR (OT incident): <15 min / ≤2 h.
- DR: RTO ≤ 4 h / RPO ≤ 15 min for historian/OMS.
8) Minimal BOM (aligned to your matrix)
Licensed Microwave, MPLS/DIA, SD-WAN/SD-Branch, LTE/5G FWA, SATCOM, Private 5G (optional), OT Gateways, Data Diode (optional), Local Historian, SASE/SSE (ZTNA/SWG/CASB/FWaaS/DLP), IdP/PAM, HSM/KMS, SIEM/NDR/SOAR, AIOps, ITSM/CMDB, EMS/DMS/ADMS, AMI/DER head-ends.