Architecture 11 — Public Safety / NG911 (Mission-Critical Communications)

Reference Architecture Diagram + Narrative (i3, ESInet, CAD, radio interop)

                         ┌────────────────────────────────────────────┐
                         │                ROLES & NODES               │
 Call-takers │ Dispatch │ Supervisors │ Field Units │ IT/Sec │ Mutual-Aid PSAP
                         └───────────┬─────────┬────────┬─────┬───────────────┘
                                     │         │        │     │
                                     ▼         ▼        ▼     ▼
         ┌──────────────────────────────────────────────────────────────────┐
         │                 PSAP / ECC FACILITY EDGE (HARDENED)              │
         │ SD-BRANCH / SD-WAN (dual underlays)  |  NAC/NGFW  |  ZTP         │
         │ VRFs: Call handling | CAD | Admin IT | Guest       | Training     │
         │ Local SBC pair for SIP; QoS: 911 voice > CAD > admin > guest     │
         └───────────────┬───────────────────────────────┬──────────────────┘
                         │                               │
        DIA/MPLS diverse paths to ESInet/NGCS            │  LTE/5G FWA kit (failover),
        (physically separated carriers & routes)         │  SATCOM trailer (DR/mobile PSAP)
                         ▼                               ▼
              ┌──────────────────────────────────────────────────────┐
              │              ESInet / NGCS FABRIC (NENA i3)          │
              │  • SIP/HELD/HELD+  • ECRF/LVF  • BCF/PRF  • LoST     │
              │  • Policy routing (origination, location, media)     │
              └───────────────┬───────────────────────────┬──────────┘
                              │                           │
                              ▼                           ▼
     ┌────────────────────────────────┐      ┌─────────────────────────────────┐
     │  PSAP CORE APPLICATIONS        │      │  INTEROP & PUBLIC CHANNELS      │
     │  • Call handling (voice/RTT/SMS)│     │  • LMR gateways  • MCPTT/MCX   │
     │  • CAD/AVL/GIS                  │     │  • Sirens/alerts • CPaaS (SMS) │
     │  • Recording/WORM archive       │     │  • Public apps/portals (WAF)   │
     │  • QA/WFO • Language services   │     └───────────────┬────────────────┘
     └───────────────┬────────────────┘                      │
                     │                                       │
                     ▼                                       ▼
      ┌──────────────────────────────────┐      ┌────────────────────────────┐
      │  SECURITY & IDENTITY FABRIC      │      │   DATA / ANALYTICS / DR    │
      │  • IdP/SSO/MFA • ZTNA • PAM      │      │  • Data lake • BI • AI/LLM │
      │  • SASE/SSE: SWG/CASB/FWaaS/DLP  │      │  • DR site/Cloud on-ramps  │
      │  • SIEM/NDR/SOAR (CJIS tagging)  │      │  • Immutable evidence vault │
      └──────────────────────────────────┘      └────────────────────────────┘

 Observability & Compliance bus ─────────► NOC/SOC + AIOps + ITSM/CMDB + CJIS/NENA dashboards

Narrative (how the emergency fabric stays coherent under stress)

1) Purpose & posture

  • Objective: Ensure every emergency call is received, located, recorded, dispatched, and auditable with five-nines availability and NENA i3 interoperability.
  • Posture: Zero-Trust by default, defense-in-depth, diverse carriers/routes, and policy-driven location/media handling.

2) PSAP edge & transport (syntax of the network)

  • Hardened PSAP edge runs SD-WAN/SD-Branch with dual-diverse DIA/MPLS to the ESInet/NGCS, plus LTE/5G FWA and deployable SATCOM for continuity.
  • VRF segmentation isolates Call handling, CAD, Admin IT, Guest/Training; QoS always prioritizes 911 voice/RTT then CAD.

3) ESInet / NGCS (semantics preserved by i3)

  • NENA i3 core (ECRF/LVF, BCF, PRF, LoST) provides location validation, policy routing, and session border control for voice, text-to-911, real-time text (RTT), and multimedia.
  • Mutual-aid PSAP paths pre-staged for overflow/evacuation scenarios.

4) PSAP core apps & interop

  • Call handling integrates RTT/SMS/MMS and language services; CAD/AVL/GIS drives dispatch; WORM-immutable recording meets legal retention.
  • LMR gateways and MCPTT/MCX bridge radio/smartphone users; CPaaS provides mass notifications.

5) Security & identity (trust zones)

  • IdP/SSO/MFA + ZTNA enforce least-privilege access; PAM gates admin tasks.
  • SASE/SSE stack (SWG/CASB/FWaaS/DLP) protects admin/SaaS flows; SIEM/NDR/SOAR with CJIS-aware tagging automates containment (e.g., SIP flood isolate, account lock).

6) Data, analytics & DR

  • Evidence chain: recordings, CAD events, location traces stored in geo-pinned, immutable vaults.
  • Cloud on-ramps provide private access to analytics/AI for QA/WFO, call forecasting, staffing; DR site mirrors call handling and CAD for rapid switchover.

7) Resilience patterns

  • Automatic failover to alternate ESInet path, mutual-aid PSAP, or mobile PSAP kit in <30 s; dispatch CAD maintained via LTE/5G when fixed links fail.
  • DDoS/call flood playbooks: SBC/SIP policies and SOAR actions block spoofed sources without harming legitimate calls.

8) Telemetry & compliance (pragmatics)

  • AIOps watches call setup, abandonment, MOS, CAD latency; ITSM/CMDB anchors changes and assets.
  • Dashboards expose NENA/CJIS/FCC posture, retention status, and drill outcomes.

9) Reference KPIs

  • Availability (PSAP): ≥99.999%
  • Call setup: <2 s; Failover: <30 s (trunk/PSAP)
  • CAD RPO/RTO: ≤5 min / ≤2 h
  • Flood containment MTTR: ≤15 min
  • Evidence retention adherence: 100%

10) Minimal BOM (aligned to your matrix)

DIA/MPLS (diverse), SD-WAN/SD-Branch, LTE/5G FWA, SATCOM kit, ESInet/NGCS interconnects, SBC/SIP, Call handling + CAD/AVL/GIS, Recording/WORM, LMR gateway + MCPTT/MCX, SASE/SSE (ZTNA/SWG/CASB/FWaaS/DLP), IdP/MFA/PAM, SIEM/NDR/SOAR, AIOps, ITSM/CMDB, CPaaS.