APIs and their relevance in 5G
By Ananya Mahanti
Post-doctoral Research Associate, Northeastern University.
APIs (Application Programming Interfaces) can be understood as a bridge between two applications or services, that allows them to communicate with each other and process data transfers [2,4,5]. They have an increasingly crucial role to play in the coordinated functioning of the network infrastructure, as 5G proposes to further the opening of the network infrastructure. The opening of the RAN infrastructure  is expected to encourage the participation from a larger number of network equipment vendors and prevent vendor lock-in problems for network operators. This essentially means segregation of equipment functionalities and standardization of the interfaces by which these different components must interact with one another. These APIs help network operators to render their existing network infrastructure towards the development of independent applications. As network services grow into their next generation, not only is there a need to evolve existing APIs but also to develop new interfaces for supporting added functionalities.
Unlike UIs (User Interfaces), which are targeted for use by end user, APIs are targeted for use by application programmers. The aim of APIs is to make programming, developing, and integrating new applications simpler, by providing commonly used functions, as tools where calling the API would get the required job done. System operators can open their system data by providing APIs whereby it becomes easier for third-party application developers to develop new applications to be integrated into the existing system, as a lot of the system workings are abstracted by the API.
APIs can be thought of as a subset of SaaS (Software as a Service), where while a SaaS may have a user interface (say a GUI), APIs typically do not. APIs may be of different types: REST, SOAP, Push, etc. APIs may also be categorized as Northbound, Southbound, Eastbound and Westbound based on their direction of communication, in say a network stack, where an API communicating from SDN (Software Defined Network) controller to a higher layer can be termed as Northbound, while East/West bound can refer to the communication between different servers.
In 5G, one of the main revenue channels for network operators is through the network services provided. Releasing APIs to fetch specific data from their system is expected to open their systems towards the development of applications that cater to the 5G paradigm. For example, the xApp APIs allow faster development of xApps, for integration into the Near Real-time RAN Intelligent Controller, towards intelligent controlling of the RAN parameters and functions .
Explore the 5G and Open RAN focused APIs on RFDataFactory here: Application Programming Interfaces (APIs) | RFDataFactory.
1. O-RAN ALLIANCE Accessed: 03/30/2022.
2. 5G Application Program Interfaces - ISEMAG Accessed: 03/30/2022.
3. Mayer, Georg. "RESTful APIs for the 5G service based architecture." Journal of ICT Standardization (2018): 101-116.
4. What is an API? (redhat.com) Accessed: 03/30/2022.
5. What is an Application Programming Interface (API) | IBM Accessed: 03/30/2022.