Devices are becoming increasingly interconnected; linked with each other and with humans. The internet of things(IoT) concept is currently used in machine to machine (M2M) applications like power, gas, and oil utilities transmission and transport. The most profound challenge that IoT faces is how to connect several very different devices into a network of things. In this regard, the standard for sending information between devices supporting IoT is called ZigBee, also known as the IEEE 802.15.4-2006 standard: ZigBee is indispensable to the functioning of the IoT. In this paper, OPNET has been used to simulate two quite differently scaled Wireless Sensor Network environments. The two environments had quite different ZigBee topologies; thus, an analysis of the performance in regard to each topology could be made. We propose,ZigBee as optional addressing method for smart-things making up the smart world which facilitates the transmission and analysis of data automatically.