October 31, 2014 | Written by: Taymour El Erian
Share this post:
The models of infrastructure as a service (IaaS), platform as a service (PaaS) and software as a service (SaaS) have been around for some time now. As time goes by, more and more “as a service” models are being introduced. Since there are so many of them, we can be said to be heading into the “X” as a service or “XaaS” era.
Let’s take a look at each of the different service delivery models one by one and see how they work.
Infrastructure as a Service
“Infrastructure” in IaaS is referring to all information technology (IT) infrastructure components, including servers (sometimes referred to as compute), networking, storage, security and so on. In this model, the service provider would provide the client with the infrastructure components housed in its managed facility. All of the hardware is owned by the provider and used by the client. This model is well suited for clients who want to take control of their IT without having capital expenses and the hassle of managing a data center.
Platform as a Service
“Platform” in PaaS is talking about the computing platform. In this case, the provider supplies the operating system in addition to the infrastructure components provided in IaaS. This model is well suited for clients using custom software applications.
Software as a service
“Software” in SaaS is referring to software applications. In addition to what is offered in PaaS, the provider supplies software applications for the client’s use. Applications like customer relationship management (CRM), messaging and collaboration, document processing and enterprise resource planning (ERP) are just a few examples of what can be offered in a SaaS model. This model is well suited for clients who are looking for a managed service with standard applications for business use and who want short deployment times.
Which is which?
A good analogy to keep these services straight is to compare them to getting a new flat. Say the flat is empty—there isn’t even paint on the walls. This would be IaaS. In this case, you would have to do the paint work yourself, and you would have to buy furnishings to your liking. However, if you get the same flat with the walls already painted and some kitchen appliances like a refrigerator and stove, it would be like a PaaS. Finally, if you buy your flat completely furnished and ready to move into, that would be like SaaS.
The XaaS family
It is noteworthy that the service delivery models in this blog post form the foundation of cloud computing. However, the three models above can also be provided on physical resources (servers, storage, network and so on).
We have gone through the three famous “as a service” family members, but there are still others that are evolving. These range from disaster recovery as a service (DRaaS) to database as a service (DBaaS). Hence comes the XaaS era. What do you think will be the next member of the “as a service” family?
For follow-up articles and discussions, please follow me on Twitter @telerian74.