Content for TR 23.722 Word version: 15.1.0

0 Introduction p. 7

In 3GPP, there are multiple northbound API-related discussions e.g., APIs for Service Capability Exposure Function (SCEF) functionalities defined in TS 23.682, API for the interface between MBMS service provider and BM-SC defined in TR 26.981. To avoid duplication and inconsistency of approach between each individual API activity, 3GPP has considered the development of a common API framework (CAPIF) that includes common aspects applicable to any northbound APIs.

The present document identifies a common approach for API development within 3GPP, corresponding solutions for the CAPIF for 3GPP northbound APIs, and recommendations for normative work.

1 Scope p. 8

The present document is a technical report which identifies the architecture aspects necessary for the development of a CAPIF for 3GPP northbound APIs, and corresponding architectural solutions. The aspects of the study include identifying architecture requirements for the CAPIF (e.g. registration, discovery, identity management) that are applicable to any service APIs when used by northbound entities, as well as any interactions between the CAPIF and the service APIs themselves.

The study takes into consideration the existing work within 3GPP related to APIs as well as API frameworks defined outside 3GPP. The recommendations from the study include architecture solutions that may be considered for normative work, based on the gap analysis of the identified architecture requirements and the existing solutions.

2 References p. 8

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.

References are either specific (identified by date of publication, edition number, version number, etc.) or non specific.
For a specific reference, subsequent revisions do not apply.
For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.

[1]

TR 21.905: "Vocabulary for 3GPP Specifications".

[2]

TS 23.682: "Architecture enhancements to facilitate communications with packet data networks and applications".

[3]

TR 26.981: "MBMS Extensions for Provisioning and Content Ingestion".

[4]

TS 29.122: "T8 reference point for Northbound APIs".

[5]

TS 29.155: "Traffic steering control; Representational state transfer (REST) over St reference point".

[6]

TS 29.198-01: "Open Service Access (OSA) Application Programming Interface (API) Part 1: Overview".

[7]

TS 29.201: "Representational State Transfer (REST) reference point between Application Function (AF) and Protocol Converter (PC)".

[8]

TS 32.240: "Telecommunication management; Charging management; Charging architecture and principles".

[9]

ETSI GS MEC 009 (V1.1.1): "Mobile Edge Computing (MEC); General Principles for Mobile Edge Service APIs".

[10]

ETSI GS MEC 003 (V1.1.1): "Mobile Edge Computing (MEC); Framework and Reference Architecture".

[11]

ETSI GS MEC 011 (V1.1.1): "Mobile Edge Computing (MEC); Mobile Edge Platform Application Enablement".

[12]

RFC 6749: "The OAuth 2.0 Authorization Framework".

[13]

OMA-AD-NGSI-V1_0-20120529-A: "Next Generation Service Interfaces Architecture".

[14]

OMA-ER_Autho4API-V1_0-20141209-A: "Authorization Framework for Network APIs ".

[15]

OMA-TS-NGSI_Registration_and_Discovery-V1_0-20120529-A: "NGSI Registration and Discovery".

[16]

OMA-TS-REST_NetAPI_Common-V1_0-20180116-A: "Common definitions for RESTful Network APIs".

[17]

OMA-WP-Guidelines_for_RESTful_Network_APIs-20140227-A: "Guidelines for RESTful Network APIs".

3 Definitions, symbols and abbreviations p. 9

3.1 Definitions p. 9

For the purposes of the present document, the terms and definitions given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905.

API:

The means by which an API invoker can access the service.

API invoker:

The entity which invokes the CAPIF or service APIs.

API invoker profile:

The set of information associated to an API invoker that allows that API invoker to utilize CAPIF APIs and Service APIs.

API exposing function:

The entity which provides the service communication entry point for the service APIs.

Common API framework:

A framework comprising common API aspects that are required to support service APIs.

Northbound API:

A service API exposed to higher-layer API invokers.

Onboarding:

One time registration process that enables the API invoker to subsequently access the CAPIF and the service APIs.

Service API:

The interface through which a component of the system exposes its services to API invokers by abstracting the services from the underlying mechanisms.

For the purposes of the present document, the following terms and definitions given in 3GPP TS 29.198-01 [6] apply:

Service Capability Server (SCS)

For the purposes of the present document, the following terms and definitions given in TS 32.240 apply:

Offline charging

Online charging

3.2 Abbreviations p. 9

For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905.

ACL

Access Control List

AEF

API Exposing Function

Application Function

API

Application Program Interface

Application Server

BM-SC

Broadcast Multicast Service Centre

CAPIF

Common API Framework

CRUD

Create, Read, Update, Delete

DASH

Dynamic Adaptive Streaming over HTTP

DDoS

Distributed Denial of Service

DNS

Domain Name Servers

ETSI

European Telecommunications Standards Institute

Group Specification

HATEOAS

Hypermedia As The Engine Of Application State

HPLMN

Home PLMN

HTTP

Hyper Text Transfer Protocol

HTTPS

Hypertext Transfer Protocol Secure

IDL

Interface Definition Language

IETF

Internet Engineering Task Force

IoT

Internet of Things

Internet Protocol

IP-CAN

IP Connectivity Access Network

ISG

Industry Specification Group

JSON

JavaScript Object Notation

MBMS

Multimedia Broadcast and Multicast Service

MEC

Multi-access Edge Computing

MMS

Multimedia Messaging Service

MTC

Machine Type Communication

NAPS

Northbound API for SCEF - SCS/AS Interworking

NDS/IP

NDS for IP based protocols

NFV

Network Functions Virtualization

NGSI

Next Generation Service Interfaces

OAI

Open API Initiative

OAuth

Open Authorization

OMA

Open Mobile Alliance

OWSER

OMA Web Services

Protocol Converter

PCC

Policy and Charging Control

PCRF

Policy control and Charging Rules Function

PLMN

Public Land Mobile Network

REST

REpresentational State Transfer

RPC

Remote Procedure Call

RTP

Real Time Protocol

SCEF

Service Capability Exposure Function

SCS

Service Capability Server

SMS

Short Message Service

SOAP

Simple Object Access Protocol

TCP

Transmission Control Protocol

TLS

Transport Layer Security

TSSF

Traffic Steering Support Function

UDDI

Universal Description, Discovery and Integration

User Equipment

URI

Uniform Resource Identifier

URL

Uniform Resource Locator

VOD

Video On Demand

VPLMN

Visiting PLMN

WSDL

Web Services Description Language

XML

eXtensible Markup Language