49 that departments must optimise their ICT resources, based on a standard data centre principle, which basically means merging of ICT resources into a single physical or logical data centre by providing the delivery of necessary services from this data centre to the department institutions’ users. It was also determined that it is necessary to consolidate the ICT support services creating a single ICT support service in the department. More significant ICT infrastructure centralisation began in 2013, confirming the concept of “Organisational Model of the National Information and Communication Technology Management”, in which a partly centralised management model was chosen for single national ICT management and a process of future national ICT resource optimisation was outlined. The leitmotiv of these initiatives is gradual transformation of national ICT infrastructure architecture, anticipating progressively higher centralisation and sharing level of its elements both at the department level and national level. For the purposeful implementation of such process, it is preferable to introduce activities that allow obtaining national ICT infrastructure architecture that is designed and maintained centrally as possible providing its usage in a sharing mode for the entire public administration supplying all the necessary high quality infrastructure services centrally and coordinated. In order to ensure the rational use of resources, centralisation cannot be an end in itself, so before the commencement of centralisation, it is necessary to evaluate alternatives and in each case economically the most advantageous solution should be chosen. Required Actions One of the most promising technological options that will allow the development of such ICT infrastructure, is cloud computing, as well as hardware and network virtualisation. By developing the existing ICT infrastructure optimisation activities, the public administration should obtain three to five logically joinable, interchangeable data centres that would be able to provide utilisation of maximally rational ICT resources. This logical combination of ICT resources would create a public administration cloud computing centre that will be able to deliver all typical cloud computing services to public administration institutions (platform as a service, software as a service, infrastructure as a service, workstation as a service). Cloud computing centre initially would be based on the existing ICT infrastructure basis of public administration, taking into account the expected life cycle and period of depreciation for the use of its elements. Planning the renewal or extension of elements of centre infrastructure in the further operation of such centre, the possibility, to use the private sector provided cloud computing services, will be evaluated, considering functional, security and other requirements necessary for public administration, as well as the overall economic benefit. This ICT business model requires good coordination and monitoring, as well as precise and clear service level agreement, which should be provided by providing optimal administration of public sector ICT infrastructure, since this is the only way to obtain maximum cost-effective ICT solution. Thus it would be possible to supply for users both – standard infrastructure services – such as email, data storage, database management systems, etc., – and centrally host SIS. information_society_development_guidelines_2014_2020.docx; Information Society Development Guidelines 2014-2020