Azure

For large and small organisations to government and enterprise, there is hardly a day goes by without some mention, consideration or use of Cloud Computing. So, it’s hardly surprising that Cloud has had so much publicity both good and bad when it come to claims of functionality, price and performance. Today Cloud vendors and organisations calling themselves Cloud vendors offer an ever increasing array of Cloud Services and it’s easy to lose sight of just what constitutes Cloud Computing. In their book “The Cloud at your service” Rosenberg and Mateos offer;

“We can summarise the five main principles of Cloud Computing as follows:

Pooled computing resources available to any subscribing users

Virtualised computing resources to maximise hardware utilisation

Elastic scaling up or down according to need

Automated creation of new virtual machines or deletion of existing ones

Resource usage billed only as used

We assert, with very few notable exceptions, that these five main principles are necessary components to call something Cloud computing”.

So how does Cloud work in world where we have built and understood IT systems based on the OSI Seven Layer model, sometimes referred to as the Stack. As data passes through the seven layers, it is changed into different forms. You will no doubt be familiar with when a user connects to the internet, their IP address at the Layer 3 network layer of the OSI Model has to be converted into a MAC address at Layer 2 for transmission, and when the data from the user reaches its destination, this process is reversed.

It is important for us to understand the Seven Layer model as Cloud computing occupies different layers of this Stack depending on what type of service it is. Understanding the Stack will go a long way towards informing you of your best Cloud computing options and especially the API’s used to communicate with Cloud services.

Broadly speaking there are three layers of Cloud computing; Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS), and Infrastructure-as-a-Service (IaaS).


SaaS is the one of the most commonly used types of services in the Cloud world due to the wealth of APIs designed to take advantage of them. A great example of SaaS is Microsoft’s Office 365, a productivity application containing all of Microsoft’s traditional Office applications and the addition of Outlook mail. All of these applications tie into a central server and deliver data to the account holder through an agreed upon methodology, such as Active Directory. The SaaS applications is paid for by the user as monthly fee, there are no traditional licenses involved.

PaaS is a Cloud computing model that can also deliver applications over the Internet. In a PaaS model however, the Cloud provider delivers hardware and software tools needed for an applications development to the client (usually an in house development team) as a Service. A Cloud PaaS provider hosts the hardware and software on its own Cloud infrastructure. As a result, PaaS frees developers from having to install in-house hardware and software to develop or run new applications.

IaaS is the base physical layer of the Cloud computing stack. Put simply we can define it as “all the infrastructure designed to allow the other services to function”. Where PaaS provides added benefit through the inclusion of a platform, IaaS provides the physical infrastructure for data transmission, calculation, manipulation, and presentation. And where SaaS provides a virtualised or remote system to work within, IaaS is the mode through which these services are provided.

+ SaaS

SaaS is the one of the most commonly used types of services in the Cloud world due to the wealth of APIs designed to take advantage of them. A great example of SaaS is Microsoft’s Office 365, a productivity application containing all of Microsoft’s traditional Office applications and the addition of Outlook mail. All of these applications tie into a central server and deliver data to the account holder through an agreed upon methodology, such as Active Directory. The SaaS applications is paid for by the user as monthly fee, there are no traditional licenses involved.

+ PaaS

PaaS is a Cloud computing model that can also deliver applications over the Internet. In a PaaS model however, the Cloud provider delivers hardware and software tools needed for an applications development to the client (usually an in house development team) as a Service. A Cloud PaaS provider hosts the hardware and software on its own Cloud infrastructure. As a result, PaaS frees developers from having to install in-house hardware and software to develop or run new applications.

+ IaaS

IaaS is the base physical layer of the Cloud computing stack. Put simply we can define it as “all the infrastructure designed to allow the other services to function”. Where PaaS provides added benefit through the inclusion of a platform, IaaS provides the physical infrastructure for data transmission, calculation, manipulation, and presentation. And where SaaS provides a virtualised or remote system to work within, IaaS is the mode through which these services are provided.


A great example of this is the provision of Cloud Data Centers to corporations. Catering for large amounts of low cost storage space, high performance multiple compute options, and extreme processing flexibility. Microsoft’s Azure is an example which provides either disk space, processing, or physical network assets for remote access and use.

Today Cloud providers offer many more services. As more of the services that used to reside in the Client owned Data Center become available for a lower cost and are usually accompanied by better performance and scalability. Below we can see just some of the many services over and above IaaS, PaaS and SaaS, offered within the Microsoft Azure Cloud.

If we look at just one service; Azure Active Directory (AAD), this allows users the ability to replicate and synchronise the important service of Active Directory on site to a Cloud based Active Directory AAD. Now remote users are able to certify against a Cloud based service without the need to come on and then leave the premise to access the Cloud service. More importantly the service is now able to be seamless to the user with Single Sign On to applications no matter where they reside.

Would you like to know how Cloud can benefit your organisation? Find out how with our Cloud Assessment and Planning services.