A very prominent tendency to cloud computing architecture is that it is for a service-oriented concerns. All functions will be broken down into a number of user needs can be assembled together according to the needs of primitive.Unfortunately,unless you are aware of all the avialable services very clearly,it would be difficult to find the best way to one of these functions can be polymerized together.It is much easier to use structure and model to expound the relationship between the various services.
The most common method uses a classification model for the named SPI,which put into service as SaaS,PaaS and LaaS,is called software as a service,platform as a service,infrastructure as a service.Amazon Elastic Compute Cloud(EC2) is a classic example of IaaS.Google App Engine is usually considered to be a PaaS,and Salesforce.com is an example of the best known of SaaS.