Virtualization- cloud computing utilizes server and storage virtualization extensively to allocate/reallocate resources rapidly

Multi-tenancy -resources are pooled and shared among multiple users to gain economies of scale

Network-access - resources are accessed via web-browser or thin client using a variety of networked devices (computer, tablet, smartphone)

On demand - resources are self-provisioned from an online catalogue of pre-defined configurations

Elastic -resources can scale up or down, automatically

Metering/chargeback -resource usage is tracked and billed based on service arrangement

Among the many types of cloud computing services delivered internally or by third party service providers, the most common are:

Software as a Service (SaaS) – software runs on computers owned and managed by the SaaS provider, versus installed and managed on user computers. The software is accessed over the public Internet and generally offered on a monthly or yearly subscription.

Infrastructure as a Service (IaaS) – compute, storage, networking, and other elements (security, tools) are provided by the IaaS provider via public Internet, VPN, or dedicated network connection. Users own and manage operating systems, applications, and information running on the infrastructure and pay by usage.

Platform as a Service (PaaS) – All software and hardware required to build and operate cloud-based applications are provided by the PaaS provider via public Internet, VPN, or dedicated network connection. Users pay by use of the platform and control how applications are utilized throughout their lifecycle.