Cloud computing as form long time and is a recently evolved computing terminology or metaphor based on utility and consumption of computing resources. Cloud computing involves deploying groups of remote servers and software networks that allow centralized data storage and online access to computer services or resources. The layered model of services on which the working of cloud-computing is based is presented in this paper. As the trends of using all services form remote platform without making it private by pay-per-use basis is growing on increasing, the service categories is cloud platform is widening their service areas.