Recently, the popularity of cloud computing has greatly increased. This is due to the way it reduces the cost of on-premises infrastructure and improves efficiency. First and foremost, the cloud model has been divided into three service categories: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). We will discuss each of these examples in the following sections:
Infrastructure as a Service (IaaS)
Infrastructure-as-a-service usually provides infrastructure such as servers, virtual machines, networks, operating systems, storage, etc., for a fee based on usage. IaaS providers provide VMs ranging from small to large computers. Moreover, IaaS allows you to choose the instance type completely freely according to your requirements:
Common cloud providers that provide IaaS services are:
- Google Cloud Platform
- Amazon Web Services
- IBM Corporation
- HP Public Cloud
Platform as a Service (PaaS)
The PaaS model is similar to IaaS, but it also provides other tools, such as database management systems, business intelligence services, etc. For instance, the following figure illustrates the architecture of the PaaS model:
Cloud platforms providing PaaS services are as follows:
- Windows Azure
- Google App Engine
- Cloud Foundry
- Amazon Web Services
Software as a Service (SaaS)
Software as a Service (SaaS) allows users to connect to products via the Internet on a subscription basis (or sometimes helps them build private cloud solutions internally). For instance, the following figure shows the basic architecture of the SaaS model.
Some cloud vendors providing SaaS are:
- Google Application
- Salesforce
- Zoho
- Microsoft Office 365
Differences between SaaS, PaaS, and IaaS
The major differences between these models can be summarized to a table as follows:
| SaaS | PaaS | IaaS |
| Software as a service is a model in which a third-party provider hosts multiple applications and allows customers to use them over the Internet. SaaS is a very useful on-demand payment model. | In this model, the third-party provider application development platform and services are built on its own infrastructure. These tools are once again available to customers via the Internet. | In IaaS, third-party applications provide servers, storage, computing resources, etc. Then make it available to customers. Customers can use IaaS to build their own PaaS and SaaS services for their customers. |
| Salesforce, NetSuite | Google App Engine, AWS Lambda | Google Cloud Compute, Amazon S3 |
