MTC API Exposure Function

MTC-AEF is a communication engine that enables the access and control of machine type communication services by external applications. 3GPP TS 23.682 defines the architecture that allows an enterprise application to reach a device fleet without holding any mobile network signalling capability of its own, so that device reachability, non-IP data delivery, triggering and power saving become northbound APIs rather than Diameter or SS7 operations. MTC-AEF implements that exposure point — the SCEF in an evolved packet core and the NEF in a 5G core — providing an interface for invoking operations and receiving notifications, with authentication, authorization, charging and policy enforcement applied through the CAPIF Core Function.

Features & Benefits

Five service families from a single engine

Non-IP data delivery, monitoring events, on-demand QoS, device triggering and communication pattern provisioning are exposed from one node over the T8 reference point. Each family is enabled independently, so an operator exposes only the capabilities its core network supports and adds the rest without deploying a further element.

One northbound contract across EPC and 5G

The same T8 API serves subscribers on an evolved packet core and on a 5G core. MTC-AEF resolves the difference beneath the API — S6t, T6a, T4 and Rx toward an EPC, service based interfaces toward a 5G core — so an application integrated once continues to operate unchanged as the network evolves.

Event driven, with delivery that tolerates the far end

Monitoring reports, delivery receipts and uplink data are delivered to the application as asynchronous notifications. Delivery is decoupled from the signalling path and retried with backoff, so a slow or briefly unavailable application server never blocks an interface toward the core network.

Durable subscription state

Subscriptions, NIDD configurations and trigger transactions are held in a shared data store. A restart or a maintenance window does not lose an application's long lived monitoring requests, nor leave orphaned configurations behind in the HSS.

Give your own IoT applications direct device control

Device reachability, non-IP data, triggering and power saving, without touching core signalling

Deployed directly between the machine type communication application and the core network, MTC-AEF acts as the service capability exposure function for the operator's own IoT platform. Applications subscribe to device reachability and loss of connectivity events, wake devices with a trigger, deliver small non-IP payloads to constrained devices, and provision power saving and extended DRX parameters — all without any application access to core network signalling.

This mode suits an operator running its own IoT or telemetry service, and any deployment where the exposed capabilities are consumed internally rather than resold.

MTC-AEF standalone mode: the operator's own IoT application calls MTC-AEF directly over the T8 northbound API, with no intermediary; MTC-AEF (SCEF/NEF) reaches the HSS, MME, SMS-SC and PCRF in the core network.

Expose MTC APIs to a 3rd party domain with the CAPIF CF

MTC-AEF CAPIF mode, T8 API with 3rd Party Exposure

MTC-AEF 3rd party exposure mode: an enterprise or MVNO/IoT platform outside the operator domain reaches MTC-AEF over T8 through the CAPIF Core Function, which onboards, authorizes and routes the request; MTC-AEF (SCEF/NEF) reaches the HSS, MME, SMS-SC and PCRF in the core network.

Where an operator exposes machine type communication capabilities to enterprises, MVNOs or IoT platform providers, MTC-AEF publishes its service APIs to the CAPIF Core Function. The CAPIF Core Function onboards the API invoker, applies the negotiated security method and routes authorized requests to the exposure function. The consumer integrates against a standard 3GPP northbound API, while the operator retains a single point of authorization, logging and charging across every exposed capability — the same framework already used across the Slicce API exposure function family.

Technical specifications

Southbound — Evolved Packet Core

S6t — HSS — 3GPP TS 29.336

T6a — MME — 3GPP TS 29.128

T4 — SMS-SC — 3GPP TS 29.337

Rx — PCRF — 3GPP TS 29.214

Tsp — MTC-IWF — 3GPP TS 29.368

Diameter base — IETF RFC 6733

SCTP — IETF RFC 4960

Southbound — 5G Core

Nudm_EventExposure, Nudm_NIDDAuthorisation, Nudm_ParameterProvision — 3GPP TS 29.503

Nsmf_NIDD — 3GPP TS 29.542

Npcf_PolicyAuthorization — 3GPP TS 29.514

Namf_EventExposure — 3GPP TS 29.518

Architecture

3GPP TS 23.682 — Architecture enhancements to facilitate communications with packet data networks and applications

Northbound (T8 / NEF APIs)

T8 reference point for Northbound APIs — 3GPP TS 29.122 (Rel-18)

Monitoring Event — 3GPP TS 29.122

Non-IP Data Delivery — 3GPP TS 29.122

Device Triggering — 3GPP TS 29.122

CP Parameter Provisioning — 3GPP TS 29.122

AS Session with Required QoS — 3GPP TS 29.122

Enhanced Coverage Restriction Control — 3GPP TS 29.122

NEF Northbound APIs (N33) — 3GPP TS 29.522

Common API Framework (CAPIF) — 3GPP TS 29.222

Transport — HTTP/2, JSON, OpenAPI 3