Cloud services model
Cloud providers typically support a range of Everything as a Service (XaaS) products; that is, as a pay-for-use software service. Services include Networking as a Service (NaaS), Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS). Each model introduces more and more cloud vendor services. These service offerings are the value-add of cloud computing. At a minimum, these services should offset the capital expense a customer faces for purchasing and maintaining such data center equipment and replace it as an operational expense. The standard definition of cloud computing can be found via the National Institute of Standards and Technology: Peter M. Mell and Timothy Grance. 2011. SP 800-145. The NIST Definition of Cloud Computing. Technical Report. NIST, Gaithersburg, MD, United States (https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-145.pdf).
The following figure illustrates...
