5G wireless mobile networks will play a critical role in the next-generation Internet. The core network of 5G consists of virtualized network functions that provides and consumes services over service-based interfaces (SBI). HTTP is the main communication channel among the network functions. Autonomy is envisioned as a critical feature of 5G and network data analytics function (NWDAF) is standardized for minimizing user intervention in the automation of network services. NWDAF collects data from user equipment (UE), network functions and operations & maintenance centre. It processes the data to produce analytics that will be employed for network optimization and orchestration such as network slicing.