A fundamental force of IoT eases the interconnection of devices in the network, which is involved in the creation of traffic routes, and transmitting the packets from source to target destination.
The growing chances of Wireless Sensor Networks (WSNs) in day-to-day life are just the beginning and the forwarding step to inventing a highly sophisticated technology, in which the houses, cities, and even countries can be interconnected as a part of the Internet of Things (IoT) design . In this sophisticated scheme, the devices are interconnected to convey competent and helpful measurement information as well as control instructions using distributed sensor nodes. The main objective of IoT is that it allows things and people to be connected to anything, anyplace, anytime, and anyone ideally exploiting any network and services. Furthermore, IoT assures to build the world where all the interconnected objects around people communicate with each other with minimum human intervention. With the great potential, for improving the quality of lives, IoT offers enormous applications in various environments . With billions of interconnected devices in the network, the rising challenge is to design an efficient routing protocol for the IoT environment .
Efficient decision-making and real-time communication capabilities of sensors and actuators that embedded into everyday objects make the IoT gain escalated significance. Moreover, the routing carries the notable importance in IoT networks where sensors act as hosts and routers for delivering data to the gateway nodes. Many protocols have been proposed for WSNs which are applicable in the IoT. As IoT holds a set of stationary as well as moving components, many issues occur in the evolution of routing protocols where the devices communicate with each other. Owing to the rapid growth of IoT with an enormous amount of data, able to secure the data while it is in motion is paramount, which has the potential to slow down the performance of whole communication. The security is defined as the dramatic process to protect the information or an object against unauthorized access, loss, theft, and physical damage by maintaining confidentiality, and integrity about them. To ensure the wireless communication with high confidentiality, the network relies on several prominent security features. These security features include the services of authorization, authentication, privacy preservation, and data freshness which ensures any malicious attackers should not access the sensitive information. Moreover, the social certification of the current IoT technologies and solutions undoubtedly rely on the trustworthiness of received data as well as the security of private information, since the deployment of sensor nodes are easily prone to critical security issues. The conventional security concerned technologies exploited in WSN routing can extend and deploy in IoT for information confidentiality, but they likely to escalate the complexity of IoT due to its design issues and lack of adaptability. For future improvement, several domains such as identification technology, communication, and networking need further research for creating a deployment of the concept of IoT robust, reliable, and secure. .
The IoT allows everyday physical and virtual objects to connect with internet which creates opportunities for direct integration of the world into computer-based systems. The fundamental feature of IoT infrastructure design is the support for Internet Protocol (IP) connectivity, which offers the communication service over a large number of embedded devices in the IoT context. These devices are frequently called as smart objects, which are not directly operated by human beings, but exist as components in buildings or moving things, or are spread out in the environment. The IoT devices are operated in minimum resources due to the constraints of sensors in terms of energy, memory, communication bandwidth, and computational speed. These resource constraints likely to be spread to design approach in creating IoT software and hardware components. The routing over its devices is deeply influenced by the resource constraints, especially, limited and un-rechargeable battery power of the sensors which degrades the performance . In addition to the impact of energy, the other layer protocols can significantly affect the routing in terms of delay, reliability, number of retransmissions, and so on. The challenges of IoT routing are demonstrated in figure 1.
Figure 1: IoT Routing Challenges
The devices connected to Internet use an IP address as a unique identifier, in which the versions such as IPv4 and IPv6 have different address space capacity. While considering a world of interconnected objects and constantly exchanging all kinds of information, the complete volume of generated data and specific processes involved in handling of these generated data become more difficult. Due to the limited space of IPv4, the objects preferably exploit IPv6 to accommodate the exceedingly large address space and provide secure communication. The objects in IoT are not only devices with sensing capability but also provide actuation capability. For instance, locks or bulbs are controlled via the Internet. To a large extent, the global adoption of IPv6 in future IoT is critical for the prosperous development of the IoT. Moreover, the IoT routing is not applicable only to stable devices, but also it includes all kind of objects which are either moved or stable in the physical world. The state of mobility of things restricts the network connectivity and continuous monitoring in IoT environment resulting in a delay of transmission and observation. The stability and delay based routing protocols are essential for IoT . The different parameters related to the network layer and energy constraint can impact the IoT designing features while enabling IP at sensor devices and performing routing.
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