5G Core Service Consumers

This is a set of service consumer libraries and testing tools for communicating with 5G Core Network Functions.

Introduction

The 5G Core presents several Network Functions, each of which has its own set of service interfaces. This is a collection of reusable service consumer libraries designed to talk to the 5G Core Network Functions using some of these service interfaces.

In addition, command line tools are provided to demonstrate the use of these service consumer libraries.

Relevant specifications

A list of specification related to this repository is available in the Standards Wiki.

About the implementation

These libraries and tools are based upon the Open5GS framework.

Service consumer libraries

libscbsf - Binding Support Function (BSF) service consumer library

The Binding Support Function (BSF) is responsible for maintaining a mapping between UE PDU Session and the PCF which is managing that PDU Session.

The libscbsf library aids in discovery of the BSF in the 5G Core (by interrogating the NRF) and subsequently looking up which PCF is managing the PDU Session for a UE, identified by its IP address.

This library implements the service consumer end of the following service-based APIs:

• Nbsf_Management

libscpcf - Policy Control Function (PCF) service consumer library

The Policy Control Function (PCF) is responsible for applying charging and network policy to the PDU sessions of UEs. The Npcf_PolicyAuthorization service API is used at reference point N5 by an Application Function (AF) to request policy changes to the PDU session on behalf of the UE. This allows an Application Function to manipulate particular network QoS parameters for selected IP traffic flows within the PDU session.

The libscpcf library allows an application to connect to a PCF and request an AppSessionContext which it can then use to manipulate the network routing policies for traffic passing across specific application flows within a UE's PDU Session.

This library implements the service consumer end of the following service-based APIs:

• Npcf_PolicyAuthorization

Command line tools

pcf-policyauthorization

The pcf-policyauthorization tool manipulates the network Quality of Service parameters of Application Session Contexts in the PCF by using the PCF service consumer library to invoke operations on the Npcf_PolicyAuthorization service API.

The PCF address can be explicitly specified at the command line if this is already known. Alternatively, the tool can also use the BSF service consumer library to look up which PCF instance is managing the PDU Session of interest (based on the IP address of a UE registered with the AMF).

Install dependencies

To build and use the service consumer libraries and accompanying command line tools, you will need to install the following packages:

sudo apt install git ninja-build build-essential flex bison libsctp-dev libgnutls28-dev libgcrypt-dev libssl-dev libidn11-dev libmongoc-dev libbson-dev libyaml-dev libnghttp2-dev libmicrohttpd-dev libcurl4-gnutls-dev libnghttp2-dev libtins-dev libtalloc-dev meson cmake

Downloading

Release tar files can be downloaded from https://github.com/5G-MAG/rt-5gc-service-consumers/releases.

The source can be obtained by cloning the GitHub repository.

For example, to download the latest release you can use:

cd ~
git clone --recurse-submodules https://github.com/5G-MAG/rt-5gc-service-consumers.git

Building

The build process requires a working Internet connection as project dependencies are downloaded during the build.

To build the libraries and tools from the source:

cd ~/rt-5gc-service-consumers
meson build
ninja -C build

Installing

To install the built libraries and tools:

cd ~/rt-5gc-service-consumers/build
sudo meson install --no-rebuild

Running

PCF PolicyAuthorization tool

The PCF PolicyAuthorization tool can be run with a command like:

/usr/local/bin/pcf-policyauthorization -a 12.34.56.78 -n 98.76.54.32:1234

To get the full command help for the PCF PolicyAuthorization tool use the command:

/usr/local/bin/pcf-policyauthorization -h

Development

This project follows the Gitflow workflow. The development branch of this project serves as an integration branch for new features. Consequently, please make sure to switch to the development branch before starting the implementation of a new feature.