Which of the following Is a valid definition for Service Based Architecture principle (SBA)?

The Service Based Architecture (SBA) is a core principle of the 5G network architecture. In this model, network capabilities are exposed as modular, reusable "services" by Network Functions (NFs). Each NF can act as a service producer, offering specific functionalities (e.g., session management, authentication) through well-defined Application Programming Interfaces (APIs). Other authorized NFs can then discover and consume these services, acting as service consumers. This producer-consumer interaction model allows for greater flexibility, scalability, and faster deployment of new services compared to legacy point-to-point architectures.

B. This describes a cloud-native deployment platform or a Platform as a Service (PaaS) model, which is an environment for SBA, not the architectural principle itself.
C. This describes the principle of Network Function Virtualization (NFV), which decouples network function software from the underlying physical hardware resources.
D. This is incorrect because option A provides a valid and fundamental definition of the Service Based Architecture principle.

1. 3GPP TS 23.501 V17.7.0 (2022-12), "System architecture for the 5G System (5GS); Stage 2".

Section 4.2.5, "The 5G Core Network architecture", states: "The 5G Core Network architecture is defined as a Service-Based Architecture. Within the 5G Core Network architecture, each Network Function (NF) is authorized to offer services to other authorized NFs..." This directly supports the producer-consumer model described in option A.

2. Nokia White Paper (2021), "The journey to a cloud-native 5G Core".

Page 4, Section "5G Service-Based Architecture", explains: "In the SBA, the control plane functionality and common data repositories are delivered by way of a set of interconnected Network Functions (NFs), each with authorization to access each other’s services." This confirms the interaction model where NFs produce and consume services.

3. Afolabi, I., Taleb, T., Samdanis, K., Ksentini, A., & Flinck, H. (2018). "Network Slicing and Softwarization: A Survey on Principles, Enabling Technologies, and Solutions". IEEE Communications Surveys & Tutorials, 20(3), 2429-2453.

Section IV-A, "Service-Based Architecture", states: "The 5G core network is designed based on the Service-Based Architecture (SBA), where the system is composed of a set of NFs that provide services to other NFs through a common communication bus." This academic source validates the concept of NFs providing services to other NFs. DOI: https://doi.org/10.1109/COMST.2018.2815638