IoT concepts, characteristics, enabling technologies, applications and protocol stack: issues and imperatives.

The Internet of Things (IoT) has transformed the world by connecting billions of smart devices, leading to an exponential growth in momentum. The ability to connect anything to the internet has resulted in the emergence of the 'Internet of People', 'Internet of Content' and 'Internet of Services'. IoT showcases network connectivity, heterogeneity among sensing devices and future-generation enabling technologies for smart connectivity, revolutionising the way we interact with the world. IoT has extended the 4A vision of 'Anytime', 'Anywhere' with 'Anyone' and 'Anything' to the 6A vision by introducing additional concepts of 'Any path/network' and 'Any Service'. This means that IoT can provide connectivity anywhere, anytime and to anyone, regardless of the network used or the service required. These concepts enable IoT to provide seamless communication between devices and facilitate the growth of new applications and services. Smart applications such as home, agriculture, cities, grid and supply chain management have leveraged IoT to improve people's lives, making them smoother, faster and more comfortable. IoT protocol stack information, ranging from 3-layered to 5-layered architecture, is explored, including various features and supporting technologies. However, it is essential to address security concerns to ensure the safe and secure deployment of IoT devices and applications.