Constrained Application Protocol (CoAP) is a software protocol intended to be used in very simple electronics devices, allowing them to communicate interactively over the Internet. It is particularly targeted for small, low-power sensors, switches, valves and similar components that need to be controlled or supervised remotely, through standard Internet networks.CoAP is an application layer protocol that is intended for use in resource-constrained internet devices, such as WSN nodes. CoAP is designed to easily translate to HTTP for simplified integration with the web, while also meeting specialized requirements such as multicast support, very low overhead, and simplicity. Multicast, low overhead, and simplicity are extremely important for Internet of Things (IoT) and Machine-to-Machine (M2