## 3 SDN-based Intelligent Transportation System  
The future capability of the Internet as a global sensation has prompted an expanding number of gadgets that are web-engaging [24]. The integration of intelligent transportation systems (ITS) with SDNs and other technologies is represented in Figure 5. In addition, traffic in the transportation system by the Internet has become simpler as the quantity of advances in the Internet of Things (IoT) is utilized for the traffic which executives (i.e., smart ITS) imagine to altogether enhance the traffic and environment on the roads. This is essential to screen the traffic through utilizing various methods (i.e., check the speed limit, contamination validations, and crisis reaction if there should be an occurrence of street mishaps). Customarily, to illuminate such issues, closed circuit television (CCTV) cameras are utilized. However, such programs and applications are not palatable in situations where few vehicles are proceeding on the roads or highways [25]. To adapt to imitations, IoT innovation thought of various strategies in rush hour gridlock the board; for instance, ITS is imagined to fundamentally enhance the transportation and security of highways. The idea of the ITS is that all vehicles proceeding on the highways are in consistent correspondence with one another, through vehicle to vehicle (V2V) or vehicle to infrastructure (V2I) correspondence [26]. The arrangement of different advancements expected to achieve this undertaking has been moderate and pricey [27]. It includes the establishment of numerous bits of huge gear both on the highways like roadside units (RSUs) and onboard units (OBUs) [28]. This recommends a total immersion of these units essential to empower a completely useful ITS [29]. As of late, a few research networks have concentrated on discovering snappy organization and lower cost elective strategies for ITS. As of now there exist numerous conventions and models that guarantee the arrangement of ITS, since it is steady over all states and vehicles. As of late, different parts of ITS have been inquired about. ITS can give a few administrations, yet from the nature of administration, quality of service (QoS) perspective, the necessities of client fulfillment are not acceptable [30]. Moreover, the capacity of dealing with a huge solicitation is irreplaceable. Thus, as of late, a rising term, called SDN, has considered the systems administration worldview among wired and remote gadgets from a programming point of view. SDN is a rising system worldview that isolates the control rationale from the system gadget (switch or sensor hub), leaving the gadget with just information sending usefulness [31]. SDN can improve adaptability and proficiency as well as give a stage to organize the board. It additionally empowers an adaptable system of executives, which is a basic component of the Internet of Things (IoT). To adapt to these restrictions and difficulties, programming characterized organizing is the precursor, shaping the foundation of system applications. In this way, SDN shows up as a distinct advantage innovation that has upset the whole systems administration component. It decouples the system control layer from the data plane to the control and deals with the system gadgets and administrations by utilizing the deliberation of lowest level usefulness [25]. It offers help for the dynamic, versatile registering and capacity requirements of the current difficult computerized arranges and permits versatile control and activities of systems cost-adequately. SDN conquers the impediment of customary systems and gives a smart stage to determine and organize security issues. As of now, two planes of traditional systems administration, control and information plane, have been successfully isolated [6]. Due to this detachment, the information plane is left with a sending system, although the control layer is moved to the controllers.