Asynchronous open APIs to support event-driven architecture

True automation requires software that’s able to detect and react to specific events, such as a customer making a purchase or initiating an interaction. Event-driven software architecture can play a key role in enabling autonomous and zero-touch operations, so is widely used by tech companies seeking to implement autonomous solutions, and CSPs are making increasing use of event-driven software architectures for their BSS systems.

These require deployment of event streaming platforms, which conduct the production and consumption of events asynchronously – however, these are not compatible with the out-of-the-box definitions of TM Forum’s Open APIs, which are defined around the REST standard for synchronous and tightly integrated architectures. To seamlessly manage complex, autonomous digital services end-to-end, CSPs need standard APIs that are compatible with events-based systems. When in place, their IT ecosystems can achieve greater interoperability with many more internal and external stakeholder systems, and harness the full potential of 5G networks to deliver partner applications and serve enterprise needs.

To make this possible, the Async Open APIs for event-based architectures Catalyst converted the TM Forum Open APIs’ definitions into the relevant industry standard for events-based systems - the AsyncAPI format, with an accompanying interaction pattern to support process assurance. Comprising BT, CityFibre, Jio, Orange, Telenor, Verizon, Vodafone, Aria, Bit2win, EPAM, Tech Mahindra and Yupiik, the Catalyst team aimed to ensure that TM Forum Open APIs’ underlying definitions, design patterns and schemes are reused for event-based interoperability.

The advantages of an event-driven architecture

For some applications, an asynchronous, event-driven architecture will lower the time and cost of integrating new components and capabilities, such as a new AI-driven channel engagement solutions for an alternative route-to-market. It could also enable more performant sharing of data and events, for example immediately advising multiple partners and systems of a network outage issue. An event-based architecture also reduces dependency on a centralized business process orchestration authority, by streamlining interaction with external business units and supporting localized component level innovation and autonomy.

“An event-driven architecture enables operators to build a far more flexible IT architecture at lower integration cost, federates business logic to open digital architecture (ODA) components and minimizes vendor and partner lock-in,” explains Florin Tene, Enterprise Architect at CityFibre. “By extending Open APIs to event-based interactions, this Catalyst will significantly enhance the ODA for use by organizations that have adopted an event-driven architecture.”

The Catalyst has delivered tooling to convert RESTful Open APIs to AsyncAPIs Open APIs, together with a defined structure and interaction pattern for event queues to support both event notifications and event responses. The Catalyst also tested how different components can be integrated using an event streaming platform, such as Kafka, where events are based on the TM Forum Open APIs schemes and the AsyncAPI contract describes the contract, again leveraging the same operations from the TM Forum Open APIs.

The Catalyst has since demonstrated how several independent ODA components and vendor solutions can successfully interoperate using an event-based architecture. At the Innovations Lab Arena at DTW 2022, the Catalyst team presented business use-cases, such as an order-to-cash process, developed by BT, CityFibre and Verizon. The six telecoms operators that championed the Catalyst are now using the Async Open APIs to implement event-driven architectures - or to support their existing implementations - facilitating better service and resource orchestration.