NEMS / Eir 999 Trunk Integration with Carrier-Grade SIP

Overview#

A 999 call from Eir's National Emergency Management Service arrives at a Dublin Fire Brigade call-taker with caller number, caller name, and a verified location pin already populated, dual-channel SIPREC recording running, and a canonical incident already opened before the handshake completes.

The NEMS / Eir 999 Trunk Integration module provides carrier-grade SIP trunking from the Irish National Emergency Service into the DFB Command and Control call-taking surface. ANI and ALI travel with the call, redundant trunk paths sustain availability, NG112 ECRF and LVF perform location-based routing, and SIPREC streams every leg into compliant retention without manual operator effort.

Last Reviewed: 2026-05-05 Last Updated: 2026-05-05

Key Features#

Carrier-Grade SIP Trunking: Dedicated SIP trunk profile for Eir's NEMS service with dual redundant paths and active health monitoring across both legs.
ANI and ALI Presentation: Caller line identification and automatic location information arrive with the call setup so the call-taker sees number, name, and verified location before answering.
Dual-Channel SIPREC Recording: Every call leg is captured on independent recording channels with metadata describing participants, timing, and trunk identity for downstream review.
Compliance-Aligned Retention: Recordings move into a retention worker that applies clinical and emergency-services retention windows, including the longer windows required for ambulance call audit.
NG112 Location-Based Routing: ECRF and LVF lookups resolve the caller location to the correct DFB queue, station catchment, or partner agency without manual rekey.
Trunk Health and Failover: Continuous health checks across primary and secondary trunks with automatic failover and observability events when a leg degrades.
Canonical Incident on Call Presentation: The trunk integration creates a call session record and an immediate incident record through the incident linker so the call-taker is working a real incident from the first ring.
Caller and Location Auto-Population: ANI and ALI populate caller and location fields on the incident object, eliminating manual transcription during the most time-sensitive phase of the call.

Use Cases#

999 Ambulance Call Reception: A member of the public calls 999, NEMS classifies the call as ambulance, and the call is presented to a DFB call-taker with full caller and location context already on screen.
Major Incident Surge Handling: A surge of 999 calls about the same event arrives across both trunk legs without trunk saturation, with each call linked to the same emerging incident through fusion.
Cross-Agency Handover from NEMS: A non-DFB call originally answered by NEMS is transferred onto the DFB trunk with caller, location, and recording continuity intact.
Compliance Review of a Past Call: An auditor retrieves a recorded 999 call from retention storage with the original SIPREC metadata and the linked canonical incident.
Trunk Failure Drill: The primary trunk leg is taken out of service for maintenance and the secondary leg carries live 999 traffic without operator-visible disruption.
Lawful Intercept Compatibility: Recording metadata and storage formats remain compatible with established European lawful intercept retention practice for emergency communications.

Integration#

Eir NEMS Originating Service: The module terminates the carrier-grade SIP trunk presented by Eir's NEMS network and applies the Eir-specific trunk profile during call setup.
Argus NENA i3 SIP Handler: Inbound calls flow through the existing NENA i3 SIP handler in the PSAP domain so the trunk integration reuses the platform's emergency call path.
SIPREC Session Recording: The SIPREC subsystem captures both call legs and emits recording events that the retention worker consumes to apply the correct retention policy.
ESRP, ECRF, and LVF Services: The Emergency Services Routing Function uses ECRF and LVF lookups to direct each presented call to the correct DFB call-taking queue.
Incident Linker and Canonical Incident Tables: Each presented call materialises into a call session record and a canonical incident record, ready for the call-taker, dispatcher, and downstream investigators.
Trunk Health Dashboard: An admin-facing trunk health view surfaces leg status, failover events, latency, and recording continuity for operations teams.
CloudEvents Event Bus: Trunk activity emits standard CloudEvents such as argus.trunk.call_presented and argus.trunk.health_check_failed for downstream consumers and observability.

Open Standards#

NENA i3 (NENA-STA-010.3): the call presentation, queueing, and routing path align with the NENA i3 IP-based PSAP architecture for next-generation emergency communications.
ETSI TS 103 479: the trunk and routing behaviour align with the European NG112 architecture for next-generation emergency communications.
IETF Session Initiation Protocol (RFC 3261): call signalling on the NEMS trunk uses the standard Session Initiation Protocol stack.
IETF Transport Layer Security 1.3 (RFC 8446): SIP signalling is secured with the modern transport security baseline expected by carrier-grade trunks.
IETF SIPREC Architecture (RFC 7245): session recording control follows the SIPREC architecture for recording control and session identification.
IETF SIPREC Metadata (RFC 7866): recording metadata is exchanged using the standard SIPREC metadata model.
ETSI TS 102 027: the recording and retention behaviour remains compatible with established European lawful intercept retention expectations for emergency communications.
ITU-T E.164: caller numbers presented via ANI follow the international public telecommunication numbering plan.