[MUSIC] Here we see three service models. And let's first talk about software as a service or SaaS or S-a-a-S. This is where the end user application is running on a cloud infrastructure. You can use a client web browser, for example, to access this application. What's great here is that you as the end user, do not manage or control the underlying cloud infrastructure, including networks, servers, operating systems, storage or even application resources, with the possible exception of limited user specific application configuration settings. If you are the administrator, then you'd have done all the configuration tasks, like setting up the operating system, installing the application, and so on, before hand, before the end user comes to access the application. Today, SaaS is very prevalent. A great example of software as a service is Gmail. Now next we have platform as a service or PaaS or P-a-a-S. And this is where the end user can deploy his or her own, or other peoples applications, created using programming languages and libraries on the cloud platform. Again the end user does not care even a little bit about managing or controlling the underlying cloud infrastructure, like networks, servers, operating systems and storage. But, they want control over the diploid applications, and possibly some configuration settings for the application hosting environment. A great example of platform as a service today, is a cloud platform like IBM Cloud, which let's you pick and deploy applications on it. And then finally we have infrastructure as a service or IaaS. And this is where the end user really cares about the underlying processing, storage and networks that he or she wants. What does he want to do with these resources? Well, he typically wants them accessed via an operating system like Linux. You might have been learning about that recently. He still does not want to manage or control the underlying infrastructure, but has control over operating systems, storage and deployed applications on the operating system, and possibly some control of select networking components like firewalls. Now, if you've made it this far, I'd like to pose a question. Which of these three models is the easiest to implement? Well, that's not an easy question to answer. Here's one possible answer. There are thousands of software as a service applications in the world today. There are also several platform as a service tools indicated by the amount of applications that have a cloud deployable version of the application. However, there are a limited number of infrastructure as a service providers in the market. Therefore, it could be said that it's slightly more difficult to provide an infrastructure as a service environment rather than platform or software. The N-I-S-T definition also talked about deployment models. First we have the private cloud, it's owned and managed by an enterprise. Most often access is limited within the enterprise or its partner. It makes sense for organisations with resource is to use private clouds, because it drives efficiency, standardization and best practices. It retains a high degree of control, privacy and security within the organization. It enables businesses to easily customize their services as and when they need. It reduces the deployment time for new services and it can be accessed from within the organization's firewall. In contrast, a public cloud is owned and managed by a service provider, such as IBM or Google. It has the ability to limit administrative access to subscribers. It usually delivers a select set of business processes, applications, or infrastructure services on a paper use basis. It's highly standardized, which may be advantageous to some, but could be viewed as a disadvantage too. It depends on what you would like to do with it. And finally, it's usually accessible from outside the firewall. A hybrid cloud provides the advantages of both public and private clouds. For example, let's say you have a business, and the traffic to your business peeks over the weekend. Over Saturdays and Sundays, you see that your servers are running at over 90% utilization. So, how great would it be to run the application on a private cloud? Just whenever the demand peaks, and then remove them when they're not needed? Easier said than done, but that's just one use case for hybrid cloud infrastructure. [MUSIC]
