In my previous articles, I have covered what Software as a Service (SaaS) and Platform as a Service (PaaS) are.

It is now time to look at the 3rd category in Cloud Computing: Infrastructure as a Service or IaaS.

Infrastructure as a Service was first known as Hardware as a Service in early 2006, but the term “IaaS” was quickly commercialized by firms like Savvis, ATT, and BlueLock.

Infrastructure as a Service (IaaS) shares a lot of common traits with Virtualization, except that NO physical equipment exists within the office/business premises. Think of it as a complete Virtualization of the server and network rooms.

The business critical server & network equipment is completely outsourced to a third party service provider. That service provider owns the equipment, maintains it, and keeps it safe and up to date.

The service is typically billed on a pay-as-you-go basis.

The main characteristics of Infrastructure as a Service that distinguish it from the other two (2) categories in Cloud Computing are:

–          Resources delivered as a service (Pretty much everything that most business today has in their server rooms and switch closets: Servers, Storage, Network components, CPU, Memory etc.)

–          Dynamic scaling

–          Elimination of administration and maintenance

–          Variable Cost

–          Multiple tenants

–          Enterprise grade infrastructure for all

Infrastructure as a Service offers a very flexible and reliable substitute for the conventional “in-house” model. Companies are quickly taking advantage of this model and immediately realize lower implementation and maintenance costs.

HINT: All transitions from physical or “in-house” infrastructure to IaaS, have to be planned very carefully and all decisions need to be based only on solid research. Evaluate the IaaS service provider, the service contracts, the service level agreements and the SaaS application vendors that provide the applications that will reside on the rented infrastructure.