Framing a Common Definition for Cloud Computing

The channel spent years deliberating and debating the true definition of what constitutes a managed service. I don’t know if the issue was ever really settled or if the channel just got bored and moved on. Now that we’re entering the era of cloud computing, the opportunity for renewed debate over cloud computing’s definition. Frankly, I think we should skip it and follow the lead of the smart guys at the National Institute of Standards and Technology, who last week released a draft definition of cloud computing.

NIST’s Peter Mell and Tim Grance have come up with probably the best and most succinct definition for cloud computing I have yet to read. What makes it so good is that it’s what I’ve heard many people say about cloud computing and Web-based applications all tidied up in one package.

Here’s what they wrote:

Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. This cloud model promotes availability and is composed of five essential characteristics, three service models, and four deployment models.

Their essential characteristics: On-demand self-service, broad network access, resource pooling, rapid elasticity and measured service.

The three service models are software as a Service (SaaS), platform as a Service (PaaS), and infrastructure as a Service (IaaS).

And the four deployment models are private cloud (operated by and for a single organization); community cloud (resources shared by a multiple organizations but may be gated); public cloud (infrastructure and resources available to all); and hybrid cloud (a combination of two or more of the other clouds).

In their brief, Mell and Grance make all the usual caveats about how the actual implementation of cloud computing will change because of the large number of vendors, providers and applications involved, and that diversity will likely spawn unaccounted variations. However, they content that cloud computing will typically fall into this framework.

Why is having a definition for cloud computing important? Not having a common frame of reference leads to confusion in the marketplace that ultimately creates obstacles to adoption, maturation and innovation. A couple of months ago I was hosting a roundtable of a dozen large enterprise CIOs on a variety of topics. When topic turned to cloud computing, these seasoned CIOs started talking about “the cloud,” as if it were some magical medium. It was then that I started talking about the different kinds of clouds that will comprise the new online application and infrastructure delivery world.

What do you think of Mell and Grance’s definition? Does it fit the cloud computing you know? Or is this draft missing something?