There is confusion about the three main categories of cloud service models: Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Service (SaaS). Let’s define each cloud service model.
1. Infrastructure as a Service (IaaS)
Infrastructure as a Service (IaaS) is a self-service model for managing remote data center infrastructures. IaaS provides virtualized computing resources over the Internet hosted by a third party such as Amazon Web Services, Microsoft Azure or Google.
Instead of an organization purchasing hardware, companies purchase IaaS based on a consumption model. It is like buying electricity. You only pay for what you use. This model enables companies to add, delete or reconfigure IT infrastructure on-demand.
Many IT organizations rely on IaaS because they are more familiar with IaaS, especially if they have years of experience with virtual environments or strict security and regulatory requirements that can only be met through IaaS.
2. Platform as a Service (PaaS)
Platform as a Service (PaaS) allows organizations to build, run and manage applications without the IT infrastructure. This makes it easier and faster to develop, test and deploy applications.
Developers can focus on writing code and create applications without worrying about time-consuming IT infrastructure activities such as provisioning servers, storage and backup.
PaaS brings more value to cloud. It can reduce your management overhead and lower your costs. PaaS also makes it easier for you to innovate and scale your services on demand.
3. Software as a Service (SaaS)
Software as a service (SaaS) replaces the traditional on-device software with software that is licensed on a subscription basis. It is centrally hosted in the cloud. A good example is Salesforce.com.
Most SaaS applications can be accessed directly from a web browser without any downloads or installations required. However, some SaaS applications require plugins.
