## 3 System Model Overview  
In this section, the proposed scheme of mitigating broadcasting storm using multi-head nomination clustering in a vehicular content-centric network is discussed. Later on, the working of the proposed scheme is discussed in detail along with a unique feature description and its implementation in two different scenarios. As shown in Figure 1, the proposed scheme includes several clusters on the road. Each cluster has a unique id \(C=\{C1,C2,C3,\ldots,Cn\}\) and a cluster head vehicle id \(HV=\{HV1,HV2,HV3,\ldots,HVn\}\). It is represented in separate sub-part of Figure 1. Each \(HV\) shares its information with the nearest RSU. This information is maintained in cluster information table \((CIT)\). If \(HV\) changes its location, then RSU utilizes its \(CIT\) information to select a new \(HV\). The RSU maintains the \(CIT\) of clusters and content in its database to satisfy the interests of clustered vehicles. The \(HV\) cache maintains the most similar content previously requested from the network and neighbor information table (NIT). The other vehicles in the cluster save the requested content and identity of \(HV\) to forward the requests. The proposed scheme extends the naive hello packet header to obtain the information of the clustered vehicles. The novel head vehicle selection parameters include the speed of a vehicle, its location information to calculate the distance, the maximum similar cached content value, and the connection information in the cluster. If the vehicle has minimum distance from a neighbor, maximum similar cached content, maximum neighbor vehicles, and comparable speed, then it is selected as a head vehicle. This information is shared with RSU and maintained in cluster information table \((CIT)\). If there are several head vehicles nominated by clusters, then \(CIT\) entries are used to compare the information and select the most appropriate vehicle as \(HV\). The head vehicle satisfies the interest of vehicles not only in V2V communication but also in V2I communication. Initially, the distance between sender and receiver vehicles has been calculated. Equation (1) is used to calculate the Euclidean distance \(d_{i}\) between two vehicles. The \(i\) shows any number of vehicles \(i=\left\{i_{1},i_{2},i_{3},...,i_{n}\right\}\). \(d_{x1}\) is the x-coordinate and \(d_{y1}\) is the y-coordinate of the sender vehicle. \(d_{x2}\) is the x-coordinate and \(d_{y2}\) is the y-coordinate of the receiver vehicle. After receiving the location information from the one-hop neighbor vehicles, each vehicle calculates its distance from its neighbor vehicle. \[d_{i}=\sqrt{\left(d_{x2}-d_{x1}\right)^{2}+\left(d_{y2}-d_{y1}\right)^{2}} \tag{1}\]  
Speed \(s\) information is used to compare the mobility information of the vehicle. Each neighbor vehicle, which receives the speed information, calculates its speed difference to estimate the stability of the vehicle in the network using Equation (2). The disruptive communication links might be created if the speed difference between two vehicles is higher than the threshold. The \(s_{vn}\) is the speed of the receiver vehicle and \(s_{vi}\) is the speed of the sender vehicle. \[s=\sqrt{\left(s_{vn}-s_{vi}\right)^{2}} \tag{2}\]  
Each vehicle shares its location, similar cached content, speed, and one-hop neighbor information in the network. \(h\) represents the number of hop counts to estimate the neighbor vehicles in the vicinity of the sender vehicle \(v_{i}\). \(h\) is an integer number (1, 2, 3...\(n\)) to presents its connectivity in the network. The \(c\) represents the similarity of content between sender and receiver vehicle. Both are estimated using hello packet exchange. \(d\) is calculated using Equation (1). \(s\) is a speed evaluated through Equation (2). To calculate the \(V\) parameter to select the head vehicle given by Equation (3), some parameters are needed;  
Figure 1: System Model of Proposed Scheme. \(s\), \(h\), \(c\), and \(d\). This value is evaluated by each vehicle in the cluster.