The IoT envisions hundreds or thousands of end-devices with sensing, actuating, processing, and communication capabilities able to be connected to the Internet. These devices can be directly connected using cellular technologies such as 2G/3G/Long Term Evolution and beyond (5G) or they can be connected through a gateway, forming a local area network, to get connection to the Internet. --- The latter is the case where the end-devices usually form Machine to Machine (M2M) networks using various radio technologies, such as Zigbee (based on the IEEE 802.15.4 Standard), Wi-Fi (based on the IEEE 802.11 Standard), 6LowPAN over Zigbee (IPv6 over Low Power Personal Area Regardless the specific wireless technology used to deploy the M2M network, all the end-devices should make their data available to the Internet.  This can be achieved either by sending the information to a proprietary web server accessible from the Internet or by employing the cloud. #The role of protocols in IoT ...