There are three primary deployment models for cloud services: Private, Public and Hybrid Clouds.
Whether operated and hosted by your enterprise IT department or by an external provider such as Alliance Solutions, private clouds are for the exclusive use of your organization.
These are open to any number of organizations and individual users on a shared basis. Using a public cloud minimizes your initial capital investment and combines agility and efficiency with massive scalability.
These link private and public clouds, providing access to extra resources when the private cloud hits maximum utilization. Or, a hybrid cloud might split computing by tier between private and public clouds. For example, the database may reside in the private cloud while the application server is located in the public cloud.
With any of these structures, cloud computing enables an application to take advantage of idle or excess compute, storage and network capacity that is shared with other applications. The cloud is one of the keys to avoiding over provisioning and enabling efficient load balancing among your computing resources.