## 3 Secure Real-Time Detection of DoS Attacks, Prevention Measures in VANET
### DoS Attacks and Model  
Denial-of-service (DoS) attacks block the availability of computing systems and network services. Therefore, the DoS attack model is needed to mitigate these attacks. DoS attacks also overwhelm the network with excessive traffic through the channel with naturally generated messages. The computing system and network services crash. In addition, they are unable to operate as accurately and effectively as required. The computing system also denies services to legitimate users [35]. In addition, as a substitute to the system to functioning appropriately, it would rather perform other irrelevant functions not required in the network. All forms of DoS attacks, including HDSA model attacks such as DoS JSA, PD, and RCRCO/DoS attacks, can be experienced through inside and outside malicious intruders in the network. These halt provision of network availability to its real users. This occurs through flooding of the control channel with naturally generated illegal and malicious messages sent at a high speed [12]. DoS attack/RCRCO key resources include high bandwidth demands, CPU and RSU overutilization, and excessive memory computation. DoS attack/RCRCOs have a tendency to reduce the speed and volume of the legitimate network by consuming high bandwidth resources. Through DoS attack/RCRCOs, packet processing and network devices can be prevented from responding to management requests. This can effectively lock the devices by consuming excessive memory, leading to CPU and RSU overutilization of resources. Figure 2 depicts a DoS attack model (DAM), which is also an aspect of the HDSA model used in this research. DAM include vehicles that have experienced all forms of attacks, including HDSA. When DoS attack/RCRCOs occur, they result in accidents at locations X and Y. Another scenario of DoS attack/RCRCO includes high bandwidth CPU and RSU overutilization and high memory computation, which also leads to broken signals. Since vehicles cannot appropriately utilize the 802.11p beacons for message transmission, this leads to collision and congestion of other vehicles. Consequently, this also leads to an encounter of broken IEEE 802.11p beacon signals. This act also leads to not being able to fully acquire the IEEE 802.11p beacons and signals, which results in end-to-end delays to the network. Moreover, packet drop (PD), false information (FI), and jamming signal attacks (DoS JSA) occurrence in VANET is possible. In the other scenario, normal vehicles that are travelling to their intended destinations communicate with other vehicles. The vehicles utilize the unbroken 802.11p beacons and signals, which encompass V2V, V2 RSU, and RSU2 RSU communication. Based upon this scenario, the RSU and fog server connection is achieved through either wired means or by wireless means. The connection of the RSU and FS utilizes the unbroken 802.11p beacons and signals with the road-side unit to vehicle (RSU2V) communication and vehicle to road side unit (V2 RSU) communication to process information in the network. The RSU2V, V2 RSU, and V2V effective signal communication of the unbroken IEEE 802.11p beacons and signals can also be achieved through the fog server (FS) effective connection with the  
Figure 2: DoS attacks model (DAM). RSU. These effective connections, which are secure, utilize the IEEE 802.11p beacons and signals generated from the accident scenarios to sensitize awareness of the road conditions. The scenario of the vehicle information delivery may also represent congestion and collision of vehicles that are used as a standard for safe information dissemination to other vehicles and road users. Based upon this, all other normal vehicles that have not yet encountered congestion, collision, or accidents will appropriately be informed about any accident and collision or congestion situation that have occurred.