Abstract: IoT is an emerging technology wherein billions of sensors from multiple vendors are embedded with the daily objects are interconnected together to sense the data continuously depending on the context and sends these data over the internet to the central database. Data analytics in tern provides the required contextual result. This leads to comfortable life with minimum or without human intervention. This paper addresses working of IoT, general IoT architecture by considering two scenarios where we have also differentiated number of layers required for the different applications. The most important factor of IoT is to understand the essential components required to build IoT and the integration of different communication technologies. For such a scenario, our study paper mainly concentrates on the essential elements to build IoT, different IoT communication technologies and different application domains, which helps the students, researchers and those who can further contribute.

Keywords: Blutooth , Cellular Network, RFID, Sensors, Wi-Fi, ZigBee