MLC API Exposure Function

MLC-AEF is a location engine that exposes mobile subscriber positioning as a set of northbound APIs. 3GPP TS 23.271 defines the Location Services (LCS) architecture that lets a Gateway Mobile Location Centre resolve a subscriber's whereabouts without the requesting application ever touching SS7 signalling. MLC-AEF implements that gateway function — MAP, TCAP, SCCP and M3UA over SCTP toward the mobile network — so device positioning, cell identity and serving-node lookup become REST calls rather than Diameter or MAP operations, with connectivity to more than one mobile network from a single instance via its SCCP routing table.

Features & Benefits

Three positioning APIs, one gateway

Provide Subscriber Location, Anytime Interrogation and Send Routing Info For Location are exposed from a single node. An application resolves exact coordinates through the network's SMLC when one exists, falls back to last-known Cell ID when it doesn't, or simply resolves the serving node address and IMSI behind an MSISDN — without three separate integrations.

Multi-network SCCP routing from one instance

A configurable SCCP routing table — global titles, point codes, subsystem numbers, and solitary, dominant or load-sharing rules — lets one MLC-AEF instance reach several mobile networks at once and route each location query to the right one.

Overload and link state visible where operations already look

Service state, SCTP link state, M3UA peer state and overload threshold breaches are reported as SNMP traps, alongside a CDR stream per location transaction (dialog, invoke ID, MSISDN, IMSI, duration, response outcome). Positioning traffic is observable through the same tooling as the rest of the signalling estate.

Designed for exposure through the operator's API framework

MLC-AEF's configuration includes a CAPIF binding — a Core Function URL and a cyclic publishing interval — so the same three location APIs can be onboarded, authorized and routed through the Common API Framework when the operator chooses to expose them beyond its own network.

Resolve subscriber location without touching MAP or SS7

Positioning and serving-node lookup, entirely inside the operator domain

Deployed between a location based service platform and the mobile network, MLC-AEF resolves subscriber position, cell identity or serving node address on request, translating each REST call into the corresponding MAP operation toward the HLR, MSC/VLR or SMLC and returning the result over HTTP/2.

This mode suits an operator running its own LBS platform, emergency positioning service, or internal network diagnostics tooling.

MLC-AEF standalone mode: the operator's own LBS/positioning application calls MLC-AEF directly over a REST API, which translates each request to a MAP operation toward the HLR (SRIforLC), MSC/VLR (Anytime Interrogation) or SMLC (Provide Subscriber Location); every element sits inside the operator domain.

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

MLC-AEF CAPIF mode, positioning APIs with 3rd Party Exposure

MLC-AEF 3rd party exposure mode: an MVNO or public-safety LBS platform outside the operator domain reaches MLC-AEF through the CAPIF Core Function, which onboards, authorizes and routes the request; MLC-AEF reaches the HLR (SRIforLC), MSC/VLR (ATI) and SMLC (PSL) in the core network.

Where an operator exposes positioning capability to enterprises, MVNOs or public-safety and LBS platform providers, MLC-AEF publishes its service APIs to the CAPIF Core Function on the configured interval. 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 northbound API, while the operator retains a single point of authorization, logging and charging — the same framework already used across the Slicce API exposure function family.

Technical specifications

Provide Subscriber Location

3GPP TS 23.271 (LCS stage 2)

TS 29.002 (MAP-PROVIDE-SUBSCRIBER-LOCATION)

Anytime Interrogation

3GPP TS 29.002 (MAP-ANY-TIME-INTERROGATION)

Send Routing Info For Location

3GPP TS 29.002 (MAP-SEND-ROUTING-INFO-FOR-LCS)

CAPIF

3GPP TS 29.222

Transport

HTTP/2, JSON

MAP

HLR, MSC/VLR, SGSN, SMLC

3GPP TS 29.002

TCAP

ITU-T Q.771–Q.775 / ANSI T1.114

SCCP

ITU-T Q.711–Q.714 / ANSI T1.112

M3UA

IETF RFC 4666

SCTP

IETF RFC 4960

Architecture

3GPP TS 23.271 — Functional stage 2 description of Location Services (LCS)