Description
Additional Elementary Functions (AEF) represent a comprehensive set of supplementary service capabilities and functional building blocks defined within the 3GPP architecture. These functions operate as modular components that extend the basic call processing and session management capabilities of mobile networks, enabling sophisticated service delivery mechanisms. AEF encompasses various functional entities that can be deployed, configured, and combined to create complex service logic, supporting everything from basic supplementary services like call forwarding and barring to advanced multimedia communication features.
Architecturally, AEF components are typically implemented within the Core Network domain, often integrated with service control functions or application servers. These functions interact with basic call state models and session management entities through standardized interfaces and protocols. The AEF framework defines precise behavioral models, state machines, and interaction patterns that ensure consistent service execution across different network implementations and operator deployments. This standardization is crucial for interoperability and consistent user experience in multi-vendor, multi-operator environments.
Key technical aspects of AEF include their modular design, which allows operators to selectively deploy functions based on service requirements and market demands. Each AEF component follows well-defined triggering mechanisms, typically based on specific events in call/session processing or user interactions. The functions implement standardized algorithms for service logic execution, conflict resolution when multiple services interact, and fallback procedures for error conditions. This structured approach ensures predictable behavior and facilitates testing and validation of complex service combinations.
In practical network implementations, AEF components work in conjunction with subscriber databases, policy control functions, and charging systems to deliver personalized services. They process service requests, apply business logic, modify session parameters, and generate appropriate charging records. The AEF framework also includes mechanisms for service provisioning, activation/deactivation, and status reporting, enabling flexible service management. These functions form the technical foundation for the rich ecosystem of value-added services that differentiate modern mobile networks from basic connectivity platforms.
Purpose & Motivation
The creation of Additional Elementary Functions (AEF) within 3GPP standards addressed the growing need for standardized, interoperable supplementary services in mobile networks. Prior to their formal definition, operators implemented proprietary service platforms that created interoperability challenges, limited service portability, and increased complexity for multi-vendor network deployments. The AEF framework provided a standardized approach to service implementation that enabled consistent user experience across different networks and devices.
AEF solved critical problems in service deployment and management by establishing clear functional boundaries, standardized interfaces, and predictable behavior models. This allowed operators to deploy complex service portfolios with confidence in their reliability and interoperability. The framework also facilitated the development of third-party service applications by providing well-defined hooks and integration points within the network architecture.
Historically, AEF emerged as part of 3GPP's broader effort to create a comprehensive service architecture that could support the transition from basic voice services to rich multimedia communications. By defining these elementary functions as building blocks, 3GPP enabled the gradual evolution of service capabilities while maintaining backward compatibility and network stability. This approach proved particularly valuable as networks evolved through multiple generations, allowing service innovation without requiring complete network overhauls.
Release Timeline
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (17 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the standardization introduced the AEF_Authentication_API, defined by an OpenAPI schema and accompanying editor's notes. This included corrections to the API's resource model and the addition of a missing function within it. Furthermore, the release corrected AEF operations for obtaining security information and for revoking API invokers.
In Release 16, the Additional Elementary Functions (AEF) were updated with new procedures specifically for a 3rd party trust domain. This enhancement focused on refining how the AEF operates and interacts within this distinct trust environment.
- Updates to AEF procedures for 3rd party trust domain TS 23.222CR0054
In Release 17, the standardization introduced new capabilities for the AEF (Additional Elementary Functions) function, specifically adding support for AEF location and for an API invoker interface tailored for edge applications. The release also included miscellaneous corrections to the AEF_Security_API and defined formatting rules for the preferred-aef-loc query parameter within the CAPIF_Discover_Service_API.
In Release 18, the enhancements for the Additional Elementary Functions (AEF) focused on improving its discoverability. The new capabilities introduced procedures to discover a proper AEF by incorporating owner information, to facilitate discovery within interconnection scenarios, and to discover a proper AEF using IP information. These additions provided more granular and network-aware methods for locating and selecting appropriate AEF instances.
In Release 19, the work on the Additional Elementary Functions (AEF) focused on enhancements within the Common API Framework (CAPIF). The key new developments included the introduction of support for AEF instantiation within CAPIF and updates to the AEF's security procedures, specifically to the Initiate_Authentication service operation. Furthermore, corrections and an enhanced description of AEF capabilities were provided.
- Proposal for AEF instantiation support in CAPIF TS 23.222CR0261
- 23.222 CAPIF_ph3 Correction on AEF type TS 23.222CR0266
- Enhanced AEF Capabilities Description TS 23.222CR0267
- Proposal for AEF instantiation support in CAPIF TS 23.222CR0314
- Updates and corrections to the Initiate_Authentication service operation of the AEF_Security_API TS 29.222CR0431
Explore further
Broader topics and technologies where AEF plays a role.
Defining Specifications
3GPP specifications that define or reference AEF, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TR 21.905 vj00 | 3GPP Technical Terms and Definitions | Rel-19 |
| TS 23.222 vj80 | Common API Framework for 3GPP Northbound APIs | Rel-19 |
| TS 23.558 vk00 | Architecture for Edge Applications | Rel-20 |
| TS 23.700 vk00 | XR Services Application Enablement Layer | Rel-20 |
| TS 23.722 vf10 | Common API Framework (CAPIF) for 3GPP Northbound APIs | Rel-15 |
| TR 23.958 vj00 | EDGEAPP alignment with ETSI MEC and GSMA OP | Rel-19 |
| TS 28.849 vj10 | CAPIF Phase2 Charging Study | Rel-19 |
| TS 28.879 vj10 | OAM for Service Management Exposure Study | Rel-19 |
| TS 29.222 vj40 | Common API Framework (CAPIF) for 3GPP Northbound APIs | Rel-19 |
| TS 29.549 vj40 | SEAL API Specification for Vertical Applications | Rel-19 |
| TS 29.558 vj40 | Enabling Edge Applications | Rel-19 |
| TS 33.122 vj20 | Security Architecture for CAPIF | Rel-19 |
| TR 33.884 vi01 | Technical Report | Rel-18 |
