# Faudistic Platooning: Subdivide Platoons, Unite Networks, and Conquer Efficiency and Reliability
## 5 Results
### Evaluation  
Communication participants, i.e., vehicles and the central server, are denoted as nodes. Vehicles are nodes with indexes 0-11, where the index within square brackets indicates their position within the platoon: node[0] is the leading vehicle, node[11] is the last vehicle of the platoon. Node[12] is the central server. Furthermore, virtual nodes are introduced for broadcast and multicast traffic: node[13] points out multicast traffic in C-V2X. Similarly, node[14] indicates broadcasted traffic in ad hoc network. The affiliation of a vehicle to the vassalage is indicated by the number in round brackets, where vassalages with lower numbers are located further forward in the direction of travel: (0) is the first vassalage and (4) is the last vassalage of the platoon. Figure 8-15 show the data flow between all nodes of the network. The color of each node is fixed. Links are weighted based on the amount of payload exchanged between two connected nodes: a single line represents 1 kB. Figure 8 shows the communication between two vassalages: merchants of vassalages send their vassalage data to knights of the following vassalage. C-V2X is used to do this. Note that communication is one way and only between two neighboring vassalages. Once these data are received by knights, they are distributed within their own vassalage, including all vassalage members (see Figure 9). In this case, the knights forward the data to lords and merchants of their own vassalage--to two nodes in total. Therefore, in comparison with Figure 8, twice the data volume is sent. Figure 8: Merchants of each vassalage send their collected vassalage data to the knight of the following vassalage. Figure 7: Feudalistic platoon consisting of 4 vassalages visualized in Simulation of Urban Mobility (SUMO). Each vassalage consists of knight (green); lord (red); and merchant (purple). Figure 10: Lords ship vassalage data to central server. Figure 9: Knights of each vassalage distribute the data from the preceding merchant (see Figure 8) within their own vassalage. Figure 11: The vassalage lords request data from another vassalage of their platoon at the central server. Figure 12: The server replies to the requests of the lords shown in Figure 11.  
Figure 14: All vehicles broadcast their CAM messages using ad hoc network. The same message is sent redundantly to all vehicles of the platoon (multicast). Figure 13: Lords distribute the requested data received by the server (see Figure 12) among all members of the vassalage. Figure 10 shows the shipping of vassalage data to the central server, as discussed in Section 4.5. The data of the vassalage are transmitted by its lord. Lords may also request data from other vassalages. To do so, they send a request to the server indicating which data they are interested in. As illustrated in Figure 11, these requests contain only small data volumes. Requesting data requires significantly less data to be transmitted between nodes compared to shipping, that is sent at the same frequency (see Figure 10 and Table 1). The server replies to the requests illustrated in Figure 11 with data stored in the central data storage (see Figure 6) from the requested vassalages. As illustrated in Figure 12, these replies contain a relatively large data volume and go directly back to the requesters--the lords. The data size is naturally dependent on the number of vassalages the requesting lord is interested in. The received data are distributed by the lords among members of their vassalages. Again, in this case, this includes two other vehicles, namely the knight and merchant (see Figure 13). In addition to _FeudalMsgs_, CA messages are also transmitted. As the velocity remains constant, the generation rate of CAMs is constant [34]. Driving with a velocity of 30.0 m s\({}^{-1}\) results in a transmission interval of 0.2 s, which is a characteristic value for free or synchronized traffic on highways [41]. Figure 14 shows the transmission of these messages: vehicles send CAMs redundantly using both IEEE 802.11p and C-V2X.