Saas, PaaS, and IaaS: Understanding the Three Cloud Computing Service Models

IaaS (Infrastructure as a Service)

IaaS is the lowest-level cloud service paradigm which is very important. Unlike PaaS and SaaS, IaaS doesn’t include applications or even an operating system. It may simply enables access to the infrastructure needed to power or support that software. It may provide extra storage backups for corporate data, network bandwidth for a company website server, or it can even enable access to high power computing which was previously only accessible to those with supercomputers.

The IaaS also offers:

• Virtual machine disk storage
• Virtual local area network (VLANs)
• Load balancers
• IP addresses
• Software bundles

PaaS (Platform as a Service)

It defines PaaS as the cloud service model wherever the cloud is used to deliver a platform to users from they will develop, initialize and manage applications. PaaS may offerings typically include a base operating system and a suite of applications and development tools. It may eliminates the need for organizations to build and maintain the infrastructure traditionally used to develop applications. PaaS is also referred as ‘middleware’, referring to how it conceptually sits somewhere between SaaS and IaaS.

Popular PaaS products are:

• Google App Engine
• IBM BlueMix
• Apache’s Stratos

SaaS (Software as a Service)

It is the software licensing and delivery model where a fully functional and complete software product is delivered to users over the web on the subscription basis. SaaS offerings are the most widely visible of all the cloud computing service models. In fact, many of the users might be using SaaS products without even knowing it. SaaS also referred as on-demand software.

There are several SaaS applications are:

• Billing and invoicing system
• Customer Relationship Management (CRM) applications
• Help desk applications
• Human Resource (HR) solutions