These are three conversations that I had recently with a partner, a customer, and a Cisco executive (not necessarily in this order):

"Cloud refers to only private and hybrid cloud, right?"

"I thought infrastructure-as-a-service is public cloud, not software-as-a-service."

"We know how much public cloud we are using because we know what infrastructure-as-a-services we are using. What I need to know is what SaaS applications we are using."

This stood out to me in a major way. While the term "cloud" has been around for a while, there is still confusion as to what it actually means.

Let Me Explain Cloud... No There Is Too Much. Let Me Sum Up!

I like TechTarget's definition: Cloud computing is a general term for anything that involves delivering hosted services over the Internet. That service can be an application or infrastructure (like storage, computing power).

There are three types of cloud computing:

Public Cloud

A public cloud is where a service provider makes resources, such as applications and storage, available to the public or a business over the Internet.

Public Cloud includes software-as-a-service (SaaS), infrastructure-as-a-service (IaaS), and platform-as-a-service (PaaS).

In a recent survey by Six Degrees Group, 22% of business professionals believed platform-as-a-service was a new philosophy in railway management, and 16% thought infrastructure-as-a-service was a new road project, so I guess I understand the confusion!

Lets clear this up, again using TechTarget's definitions:

• SaaS is when applications are hosted by a vendor or service provider and made available to customers over a network, typically the Internet. Examples: Salesforce, Workday, WebEx, Eventbrite, Evernote
• IaaS is when a third-party provider hosts virtualized computing resources over the Internet. Examples: Amazon Web Services, Box
• PaaS a cloud provider delivers hardware and software tools, usually those needed for application development, to its users as a service. Examples: Google Application Engine, Openshift, Windows Azure

Private Cloud

Private cloud is when an enterprise builds aninternalcloud computing infrastructure to provide applications or computing resources that are protected by the company's firewall. Private clouds are built to provide cloud computing benefits internally, but provide the company more control over their data. Also, a private cloud uses a catalog of services as the portal or interface for users.

Hybrid Cloud

A hybrid cloud is a cloud computing where an organization provides and manages some resources in-house and has others provided externally. With a hybrid cloud, organizations can create a cloud environment across multiple cloud providers and between premise-based applications and the public cloud. According to IDC, More than 65% of enterprise IT organizations will commit to hybrid cloud technologies before 2016.

So, how did I do in explaining cloud computing? Feel free to let me know on Twitter or LinkedIn.

To learn more about how Cisco can help you monitor, manage, or build clouds, visit: www.cisco.com/go/cloud