In defining Infrastructure as a Service we need to drill into specific characteristics that a cloud platform provider must provide to be considered Infrastructure as a Service. This has been no easy task as nearly every cloud platform provider has recently promoted features and services designed to address the infrastructure as a service and cloud computing market. Fortunately, as the technology has evolved over time, a definition of cloud computing has emerged from the National Institute of Standards and Technology (NIST) that is composed of five essential characteristics, three service models, and four deployment models.
Want more information? Check out the full article at http://blogs.technet.com/b/privatecloud/archive/2012/04/04/what-is-infrastructure-as-a-service-iaas.aspx. Enjoy!