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Exploring SDG OpenCAPIF Release 5

A new version of OpenCAPIF is now available! Release 5.0.0 is one of the most feature-rich releases so far. It brings CAPIF Interconnection, a new Open Discover Service, and the complete implementation of Visibility Control, along with deployment, testing and security improvements.

Let’s take a look at the highlights of this new release. Each section links to the OpenCAPIF documentation, where you will find more detailed information. If you need further help, do not hesitate to contact SDG OpenCAPIF through the channels listed at the end of this article.

CAPIF Interconnection

The main feature of this release is CAPIF Interconnection. Multiple CAPIF Core Functions (CCFs), in the same or in different trust domains, can now interact with each other, discover services and publish APIs across domains. This will also ease the process of publishing for API providers in distributed environments, while keeping the control over what is shareable among CCFs.

API invokers can therefore use service APIs offered by third-party API providers connected to a different CCF, which opens the door to distributed, multi-domain CAPIF deployments.

To make this possible, several parts of the platform were extended:

  • A new Helper API manages the establishment, teardown and synchronization of interconnections between CCFs.
  • The Publish API (publish, update, modify and unpublish) now supports interconnection, so shared APIs are propagated to peer CCFs.
  • The Security Context API (create context, get, delete and create access token) now works across CCFs and supports the OAuth, PSK and PKI security methods.
  • Local scripts were improved so you can run two interconnected OpenCAPIF instances locally and test the feature on your own machine.

The security aspects of this feature follow the procedures for CAPIF interconnection described in 3GPP TS 33.122. However, the 3GPP specifications do not define in detail how the CAPIF-6/6e interface is to be implemented. The solution delivered in this release therefore constitutes a proposal by SDG OpenCAPIF on how to implement these specifications within the OpenCAPIF code base, in line with the architectural principles established by 3GPP.

📖 Learn more in the OpenCAPIF Interconnection documentation, which describes the establishment, publication and security flows between CCFs in detail. The Helper Service documentation includes the Interconnection API reference.

New Open Discover Service

Release 5 adds the CAPIF Open Discover Service API, which lets API invokers find out what an OpenCAPIF deployment offers before onboarding.

With Open Discover, an invoker can check whether a specific API, version or endpoint is available at an OpenCAPIF deployment without the need to onboard. Onboarding is then limited to the cases where the required API is actually present, saving time and operations for both invokers and the CCF.

Discovery is available through a new endpoint:

GET /open-api-disc/v1/service-apis

Unlike the regular Discover Service, the caller only needs a valid token obtained from the Register Service. Filtering works the same way as in the Discover Service, with the same standardized query parameters.

The new service is fully integrated into the deployment tooling, with its own Helm chart, updated scripts and CI/CD pipelines that build its images.

📖 Learn more in the Open Discover developer guide, which covers authentication, query parameters, error responses and example requests.

Visibility Control Is Now Fully Operational

Release 4 laid the foundations for Visibility Control. Release 5 delivers the complete implementation of the Visibility Control API as a Helper service.

Visibility Control gives providers fine-grained control over who may discover and consume their published APIs, and when. This makes OpenCAPIF easier to adapt to scenarios where API privacy is of utmost importance.

API providers and administrators can now create, update, list and delete visibility rules that decide which invokers can discover which APIs. Rules support:

  • provider selectors to target specific providers, APIs or AEFs
  • invoker exceptions
  • a default access behavior (allow or deny)
  • an enabled flag and validity periods

The Discover Service applies the active rules to every request, so each invoker only sees the APIs it is allowed to access.

📖 Learn more in the Visibility Control documentation, which includes rule examples, the access decision workflow and a summary of the available endpoints.

Same API Name Across Different AEFs

The Publish Service now checks for duplicates per AEF (aefId/apiName) instead of across the whole platform. Different AEFs can publish APIs with the same name, while duplicates from the same AEF are still rejected on POST, PUT and PATCH.

Smoother Kubernetes Deployments

The OpenCAPIF Helm charts have been split to deploy components in a structured order. This prevents unnecessary restarts, reduces the load on the deployment environment and makes the charts smaller and easier to maintain.

The change also includes:

  • the correct appVersion set in the charts
  • better control over the deployment process
  • shorter deployment times

Local scripts have also improved. They now support environments and multiple local instances, check whether the destination hosts are reachable, and provide a new script that starts two local environments to test interconnection.

📖 Learn more in the How to Deploy Using Helm and How to Run Locally guides.

Security Improvements

Security remains a top priority. The security issues detected since the previous release have been solved.

Several dependencies were also upgraded for security reasons:

  • the OpenTelemetry libraries (the Jaeger exporter was removed)
  • cryptography, upgraded to 46.0.1

The base images were refreshed as well: the NGINX image now uses the latest Debian version and all Docker images run on Python 3.13.

Alignment with 3GPP CAPIF Release 19

OpenCAPIF services remain aligned with 3GPP CAPIF Release 19, version 19.4.0, as defined in 3GPP TS 29.222 and introduced in Release 4.

This release focused on delivering new services and features, so the changes introduced in later versions of the Release 19 specifications are not yet included.

Testing

The test suite keeps growing with every release. Release 5 adds 31 new tests:

  • 11 tests for the Interconnection feature
  • 12 tests for the Visibility Control API
  • 6 tests for the Open Discover Service
  • 2 tests for publishing the same API name from different AEFs

The Robot Framework image has also been upgraded to version 2.0. It is now based on Ubuntu 22.04, has an improved Dockerfile and updated requirements, and is published in the ETSI registry.

📖 Learn more in the Test Plan and the Robot Framework guide.

Documentation Improvements

The documentation has been extended to cover all the new features:

Getting Started with OpenCAPIF 5.0.0

To deploy or test this release, clone the OpenCAPIF repository from ETSI Labs and switch to the corresponding release tag.

The documentation provides detailed guides for:

You can also try OpenCAPIF in the public sandbox environment.

If you have any questions that the documentation does not answer, the SDG OpenCAPIF team will be happy to help. You can reach us through the contact details below.

Get Involved

Want to contribute? Learn how to join SDG OpenCAPIF, it’s easy and free1! 🎉

For more information, please contact us.

Learn More

For further information, please consult the following resources:

  1. Joining is free upon signature of the SDG OCF Agreement for a variety of entity types (ETSI Members, SMEs, Universities, Public Research Bodies, etc.). ↩︎