What are the three main cloud service models?

“The three Cloud service models are IaaS, PaaS, and SaaS. IaaS (or Infrastructure as a Service) provides you with your own server environment without the need to administer the physical part of the infrastructure (datacenter, climate control, electricity, server room, etc.) With IaaS, businesses benefit from technical resources on virtual machines that can be shut down, stopped, reinstalled, or configured.”