Which of the following is NOT one of the main service models in cloud computing?

The main service models in cloud computing comprise Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). These models define different layers of service that cloud providers deliver to users.

Infrastructure as a Service (IaaS) provides virtualized computing resources over the internet. This includes things like virtual machines, storage, and networks, allowing users to rent infrastructure rather than investing in physical hardware.

Platform as a Service (PaaS) offers a cloud platform that supports the development, testing, and deployment of applications without the complexity of managing the underlying infrastructure. This model is aimed at developers and minimizes the operational tasks required to create and manage software.

Software as a Service (SaaS) delivers software applications over the internet, on a subscription basis, which users can access through a web browser, eliminating the need for installations or maintenance.

Network as a Service (NaaS) is not considered a primary service model like the others mentioned. While NaaS does involve the delivery of network services over the internet, it is generally seen as a subset or niche offering in the broader cloud service ecosystem rather than one of the foundational models. Thus, it is correctly identified as not being