In recent years, cloud computing, a term that broadly describes an emerging group of related technologies and business models, has become standard vocabulary in the private and public sectors who wish to harness the potential benefits of this technology for their organizations and businesses.[1]In particular governments are replacing their legacy IT systems with cloud computing technologies and implementing new cloud-based tools for collaboration and information sharing across agencies and units.[2]

However, an important decision for any organization that wants to join the cloud era is the selection of the appropriate cloud computing model. The basic types of cloud offerings, include infrastructure as a service (IaaS), platform as a service (PaaS), software as a service (SaaS). Each service is built on top of the other.[3]


Figure : The layers of Cloud Computing (source :

SaaS provides all software application services through a Web browser and not a locally-installed application. SaaS eliminates worries about application servers, storage and application development. Consumer is usually an end user of applications.

In the PaaS model, a hosted environment is provided to the consumer to run his applications. The consumer controls the applications that runs in the environment, but does not control the operating system, hardware or network infrastructure on which they are running. The platform is typically an application framework. Typical customer is an application developer or DevOps teams.

Infrastructure as a Service (IaaS) is the cloud model where consumer uses “fundamental computing resources” such as grids or clusters or virtualized servers, networks, storage and system software designed to augment or replace the functions of an entire data center. Typical customer must be familiar with and prepared to spend time and efforts on infrastructure management.

According to our experience from the pilot execution and the questionnaires of the project that were filled by more than 110 public stakeholders, we identified the deployment model of Software as a Service appears to be the most favourite approach, due to the ease of starting. There is also however a big part of the public sector using IaaS and PaaS or even a combination of the models (IaaS, PaaS and SaaS). This is common especially if there are cloud services that serve specific needs of the public body or there is a need for public agency to host the governmental cloud(G-cloud) provided resources (at the IaaS or PaaS level to other governmental agencies).

Trends in service and deployment models of G-Cloud solutions – Private, SaaS and “G2all” (i.e. G2C, G2B, G2G) seems to be dominating. The national G-Cloud early adopters have taken different paths in choosing for their cloud solutions. Although there are a few countries that have opted for public solutions, it appears that most countries currently working or planning towards a G-cloud lean towards Private cloud (i.e. a governmental agency hosting the G-cloud services with own-resources). Regarding the deployment model Software as a Service again appears to be the most favourite approach, although a combination of other models (IaaS, PaaS and SaaS) is also common (especially if there is a need for the agency hosting the G-cloud to provide resources (at the IaaS or PaaS level to other governmental agencies). Regarding the target audiences of G-Cloud early adopters or under planning the trend appears to be clearly towards servicing all players, i.e. citizens, business and governments, i.e. G2C, G2B, G2G.

However, a public organization that is now considering to move to the Cloud should decide the appropriate cloud model that should use. In this direction, the following parameters should be taken under consideration, in order to elect the ideal cloud model that best suits organization.

The difficulty to implement each cloud model should be taken under consideration. The decision is not easy as each model suits better different situations. If a public body would like to use an online application without extended configuration and SaaS approach is offered, this might be an ideal solution, due to the simplicity to adopt. However, specificities like imposed regulations might be tough to be accomplished in this scenario. In these cases the IaaS paradigm might be more appropriate as it offers the greatest amount of control in of the deployment environment. IaaS adoption however means that the organization is responsible creating a cloud ready application, deploy it and properly secure the server. STRATEGIC Service Store is a tool that offers the best of both worlds; it allows the configuration of both the deployment environment and the application through easy to use menus, and the same time it offers security mechanisms out of the box.

The maturity of the different cloud models can vary. Although a general conclusion it is not easy to be provided, SaaS and IaaS are the most dominant models, while PaaS reflects a smaller market with lots and often changes.

The focus of each model is different and should be taken under consideration. SaaS is commonly adopted for the usage of online services that are provided ready for use. PaaS in used for the deployment of databases and web applications created developers. IaaS are used to provide storage, server and networks that should be configured properly and then used of the deployment of applications.

The added value that each model provides is also different. The ease of deployment that SaaS provides can be considered an added value as it allows the deployment of a product ready solution with a very short turnaround time.

[1] Governments and Cloud Computing: Roles, Approaches, and Policy Considerations, Urs Gasser and David R. O’Brien, Working Paper No. 2013/23, August 2013