Welcome to the second installment of our Cloud 101 series! In this blog, we will be discussing the different service models of the cloud. So enough of this small talk, and let’s dive in!

Infrastructure as a service (IaaS)

iaasSometimes referred to Hardware as a service (HaaS), is probably the most basic model. In this service model, clients can outsource the equipment used to support operations, including hardware, servers, and storage. The service provider owns the equipment and is responsible for maintaining it. Some features include: internet connectivity, automation of administrative tasks, policy-based services, and dynamic scaling.

In comparison, IaaS-cloud providers typically supply these resources from data-centers.  IaaS usage is metered and priced on the basis of how often it is used. Pay for what you use and when you use. Thus if your usage is low so will be your bill. Because of this billing style, IaaS is beneficial for companies that have limited funds to invest in hardware.

Software as a service (SaaS)


With this model, applications are hosted by a service provider and made available to customers via the Internet. There are two slightly different delivery models for SaaS. The first model is the software on demand model. In this method, the provider gives customers network-based access to a single copy of an application that was created solely for SaaS distribution.

The other method is hosted application management (hosted AM); this is similar to ASP (application service provider) in that a provider hosts commercially available software for customers and delivers it over the Web. One of the up-sides for going the SaaS route is that the client doesn’t need to invest in any addition hardware, since the software is hosted remotely. This model is also beneficial for companies that have limited capital to spend on traditional software because SaaS is usually subscription based, so there are monthly payments instead of one large up-front fee. Also, it’s normally a subscription, so purchasers have access to system upgrades and usually some form of client support.

Platform as a Service (PaaS)


SaaS applications are designed for end-users, delivered over the web, while Paas is a set of tools and services designed to make coding and deploying those applications quick and efficient. Think of it this way: what SaaS is to applications, PaaS is to software development. PaaS is a platform for the creation of software over the web. This is especially useful in the event that multiple developers will be working on a project or other external parties need to interact with the development process. PaaS is also very helpful if developers want to automate testing and deployment services. As the utilization of agile software development grows, so will the use of PaaS, since it reduces the difficulties around rapid development. This model is also has financial benefits as well because there is no need to all of the software, tools, and kits to build and deploy an application/software. Typically, users rent the needed equipment for only the period of time where it will be used.

Well that just about does it for this installment of our Cloud 101 blog series. Stay tuned, because next time we will be discussing some of the issues you might face when choosing to use the cloud.