Infrastructure as a Service - additional information
In addition to Platform as a Service (PaaS) and Software as a Service (SaaS), Infrastructure as a Service (IaaS) is one of the three central service models of the cloud computing market.
Under infrastructure as a service, service providers sell their clients access to hardware and resources, such as servers, network, storage, or virtual machines. The client is not responsible for maintaining those resources, as the details of the physical layer are concealed. Instead, they are responsible for higher level resources, such as the platform or operating system and the software. Typically customers are billed on a utility basis; that is, a customer pays only for what they are allocated and consume. As the provider is also free to sell unused resources, there is a substantial opportunity for cost-savings and efficiency gains for both sides.
Infrastructure as a Service currently represents almost a third of the overall cloud computing market and revenues are expected to rise significantly over the coming years. However, its overall market share is expected to fall, losing ground to the maturing Platform as a Service market.
Within the Infrastructure as a Service market, the vendors with the largest market share are currently Amazon, through its Web Services offering; Microsoft, with Azure; Google, via its Compute Engine; and IBM, with its SmartCloud Enterprise. While Amazon is the largest vendor of cloud infrastructure services by some margin, its dominance over the market is lessening as the larger competitors make headway.