Cloud Layering through IaaS, PaaS & SaaS
A cloud-based offering can be provided at different levels and with different service models. We have beaten the Public vs. Private Cloud advantages subject to death here on this blog. So today’s subject will be an explanation of the various layers of Cloud offerings available.
A cloud-based offering can be provided at different levels and with different service models.
1) Infrastructure as a Service (IaaS) – A very basic, low-level infrastructure of servers with operating systems can be provided; Amazon EC2 is probably the most widely known example.
2) Platform as a Service (PaaS) – Offering more structure and composable components gives us “Platform as a Service” such as the Google App Engine or Salesforce’s Force.com.
3) Software as a Service (SaaS) – The highest level offering is a full application, “Software as a Service” such as Oracle’s “On Demand” offerings or Salesforce.com.
But be warned, the higher a level the cloud offering, the less the “customer” of the cloud has to do or build, but the more constrained he is. It’s a trade-off between effort and flexibility.
Furthermore, as you move from IaaS, to PaaS and finally SaaS, you get fewer controls and less visibility into what the service provide offers. Many Service Providers may not implement standards which can make interoperability and integration challenging.