The field of computing has covered a long path. From Mainframes to traditional desktop and then towards Ubiquitous Computing. Ubiquitous Computing combined with wireless Network embedded with cloud computing have given rise to new type of concept known as Internet of Things. But this is not the final destination. A new edge is added further to this which is known as Edge Computing or Fog Computing. With less maintenance and cost based on service usage, cloud computing's layered architecture

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... ws the client to purchase services at different levels such as IaaS, PaaS and SaaS. It permits location independence facility as users can access these services anywhere with an internet connection and a web browser. IoT devices generate data constantly, and often analysis must be very rapid. Main sources of this huge amount of data are devices, sensors or actuators. Handling the volume, variety, and velocity of IoT data requires a new computing model. Also the time it takes to makes its way to the cloud for analysis, the opportunity to act on it might be gone. So, a new model which will further enhance the capabilities of IoT is explained. This new model is known as Fog Computing or Edge Computing. There are number of applications where this model fits. In this paper introduction to Iot and its applications are discussed. Then Fog computing is introduced.