The miniaturization of sensor nodes and their wide environmental applications, despite of its unique constraints it act as the gateway for Internet Of Things(IoT) applications. The Wireless Sensor Network and its infrastructure act as the data source for IoT applications. The selection of the gateway node from these source sensor nodes, routing the sensed data packet through this gateway to the sink or server by avoiding the redundant data in energy constrained environment like WSN is still a challenge. The focal point of this book is to design and implement an energy efficient aggregation or routing techniques in IoT sensor nodes.