The three main Service Models of the Cloud Computing structure, as defined by the NIST – National Institute of Standards and Technology of the U.S. Department of Commerce, are: Software as a Service, Platform as a Service, Infrastructure as a Service.
Infrastructure as a Service (IaaS)
Any medium or large company has an IT area and, in general, dozens of servers running in-house (or on premises). These servers can run applications aimed at internal customer (email, office applications, order processing, billing, etc.) or external customer (company website, e-commerce, supplier purchases). Similarly, it may run other transactional and informational systems, such as ERP, CRM and analytical applications.
Based on the cloud services of the IaaS model you can create a virtual data center where you can install and run the desired software and systems on the necessary equipment. The difference is that these servers are virtualized, that is, their computing resources run in the cloud, are accessed over the internet, and all the services of these servers are delivered over the internet when used by internal users, suppliers and customers.
In the IaaS model, the company manages everything beyond the hardware, from the operating system onwards. It is as if the company operated its own servers “remotely” over the internet. Obviously, the provider must offer an access dashboard to control and set up machines, which gives IT staff full authority, such as:
- Easily access and set up server hardware (CPU capacity, dynamic memory (RAM) and static memory (disks)); The advantage is that you can scale more resources at any time;
- Monitor the performance of servers, data flow (I/O) and software;
- Automate resource scaling to the maximum.
In addition to the control and monitoring dashboard, some suppliers also provide APIs for their customers to set up their own monitoring, parameterization and control programs.
Basic Advantages and Benefits of IaaS
Rather than investing large sums to buy hardware, the company contracts and pays IaaS based on its demand, similarly to buying electricity or water. In doing so, fixed depreciation expenses are converted into variable costs based on the volume and production of IT services.
This also eliminates invisible or non-utility costs: resources installed in own data center as “buffers” for peak demand, which remain in “standby” most of the time.
Disadvantages of IaaS
The company can fully control the infrastructure with IaaS – which is not the case and is not necessary with the other PaaS and SaaS service models. The company remains responsible for managing applications, data and operating systems. There is no need to save with IT staff, as the people who take care of it in the internal data center start to do the same thing in the virtual data center.
As the company continues to manage all software layers, it remains responsible for updating it whenever there are new versions, service packs and patches. Moreover, the company’s IT department remains responsible for system security, data integrity, etc., except for hardware security aspects. The security requirements for systems running on IaaS are basically the same as for systems running on own data center.
Plataform as a Service (PaaS)
This model lies between IaaS and SaaS and provides a more robust and flexible platform for using several technology resources.
A company using this service can install and manage its own applications, whether developed by the service or purchased from third parties, with the tools and libraries offered by the provider. Some of these tools and libraries are standardized so that it is possible to migrate between PaaS service providers, which makes the use of software very flexible.
PaaS eliminates the need to acquire, set up and manage hardware and basic software resources. The infrastructure is invisible to the customer, but it can set up the applications and, eventually, the aspects related to the environment used by such applications. In addition to the aforementioned Google App Engine and Heroku, other examples of PaaS services are Microsoft Azure Cloud Services and AWS Cloud Compute Service, among others.
Basic Advantages and Benefits of PaaS
The main benefits of the PaaS model are reduced costs and increased speed of development and deployment. You get agility and flexibility. From a business perspective, the benefits of PaaS are:
- Increased focus on the business;
- Decreased time to market;
- More agility to react and keep up with market changes and opportunities;
- Elimination of costs and investments required for development and deployment through own data center;
- Decreased head count and costs with IT infrastructure personnel working in the company.
Software as a Service (SaaS)
Currently, there are hundreds of SaaS (Software as a Service) providers that manage everything from data storage to applications. Microsoft Office is an example: instead of installing the traditional Office suite on the company’s servers and machines, you can use Office 365, which runs in the cloud and has a licensing cost model that pays off, in addition to allowing you to use Office on mobile devices. The software is made available remotely, not only on office equipment. Another option is Google APPs for Work, which, in addition to having an excellent email system, offers integrated office automation applications, similar to Office.
As the necessary infrastructure is in the cloud (applications and data), IT personnel have more free time to handle more important tasks that add value to the business. Think about the exponential decrease in complaint calls about interruption of the e-mail system, lack of space in mailbox or about attachments that are very large, among others.
In principle, all systems that are not part of the organization’s core and, as a result, the entire infrastructure used by these systems can be replaced by SaaS solutions. The most common examples are ERPs, CRMs, the storage and validation of tax documents, among others.
Basic Advantages and Benefits of SaaS
The main benefits of the SaaS model are payment on demand and the management of environments and systems by third parties, so that the company can focus on its core business. Other benefits of SaaS are:
- Lower and decreasing costs with software and systems;
- Decreased need for investments in hardware assets and basic software;
- Released IT staff and potential decreased head count;
- Greater autonomy for users of applications, who can use the services on any device, including mobile, without requiring further development by the contracting company;
- Guaranteed data integrity (sophisticated backup and redundancy mechanisms);
- Greater service availability and capacity;
- Permanent updating and governance of environments.
Disadvantages of SaaS
- Longer latency time for real-time systems, in which case milliseconds can make a difference;
- Dependence on the internet, the means by which applications are accessed;
- Controversy over data confidentiality, as some companies or executives may consider cloud data storage a security risk.
