## 3 Road-Based Multi-Metric Forwarder Evaluation Scheme
### Multi-Metric Video Streaming with Dynamic Self-Weightting Score
#### Multi-Metric Video Streaming without Dynamic Self-Weighting Score  
The Multi-metric, which consist of VDR, VTJ, \(\rm{T_{H_{m}R_{r}}}\), ABE and SINR as discussed in Section 3.1 have been employed for selecting optimal NFV. These metrics are computed in order to select optimal NFV. The concept of the video data forwarding considering different frames based on frame splitting has been discussed earlier in Section 1. Considering the number of multi-metrics employed, an equal fixed weight value has been assigned to each of the metrics in order to evaluate the most optimal C-NFV. The vehicle with the highest multi-metric score is considered as the most optimal NFV. The weight assigned is denoted as \(\rm{weights}=\rm{wt_{1}},\rm{wt_{2}},\ldots,\rm{wt_{n}}\), n represents the number of metrics, since the number of metrics utilized are five (5), \(\rm{n}=5\). The weight of each metric is given as \(\rm{\frac{1}{5}}=0.2\). Further, the weights \(\rm{wt_{n}}\) are allocated to the metrics \(\rm{mt_{n}}\), which includes \(\rm{mt_{VDR}},\rm{mt_{VTJ}},\rm{mt_{T_{H_{m}R_{r}}}},\rm{mt_{ABE_{C-NFV}}}\) and \(\rm{mt_{SINR}}\). These metrics are normalized since they have different units. Thus, the total summation of the multi-metric score for each of the C-NFV is represented in Equation (16) as follows. \[ \begin{array}{ll}\rm{mt_{C-NFV}}&=\sum\limits_{n=1}^{5}\rm{mt_{n(C-NFV)}}=\rm {mt_{VDR}}\times\rm{wt_{1}}+\rm{mt_{VTJ}}\times\rm{wt_{2}}+\rm{mt_{T_{H_{m}R_{ r}}}}\times\rm{wt_{3}}+\rm{mt_{ABE}}\\ &\times\rm{wt_{4}}+\rm{mt_{SINR}}\times\rm{wt_{5}}\end{array}  \tag{16}\]  
In Algorithm 1, the video data forwarding procedure is highlighted. Video packet and video ID are generated including I-frame, P-frame and B-frame as discussed earlier in Section 1. The algorithm employs the multiple metrics including VDR, VTJ, \(\rm{T_{H_{m}R_{r}}}\), ABE and SINR. The five metrics are introduced into the video data forwarding algorithm in order to select an optimal NFV. Lines 1 to 10 calculate the metrics and identify the first two suitable vehicles as the RVNs, which are neighbors to the SVN for multipath transmission. At line 12, if a C-NFV is not selected as the RVN, then it is discarded. Line 13 to 19 involves the evaluation of the metrics in order to select a suitable vehicle as the NFV. A C-NFV with a maximum value of the five metrics is selected. Equal weighting factor has been assigned to the five metrics in order to assign equal priority to the metrics. In addition, after each packet forwarding, the PFV retransmit I-frame when hello message is not received from the last NFV within the period of one second, this is necessary in order to guarantee delivery of the important frame, which in turn improves the quality of the video streaming since UDP has been considered as the transmission protocol in this study. At the intermediary vehicles, lines 20 to 31 are invoked to compute the multi-metric for selecting the optimal NFV. Whenever video data is forwarded, information regarding the qualified vehicles is stored in the TNI at the vehicle \(\rm{P_{2}}\). The forwarding of video data continues until the C-NFV is the DVN, then the video packet is forwarded to DVN. The DVN receives the video data compare and discard duplicate I-frame. Then the DVN rearranges video packet for streaming and the video data forwarding procedure terminates. Figure 3 depicts the flow of the multi-metric video streaming forwarding procedure. ```
1:\(\textit{Initiate}:\) videepacket
2:\(\textit{Initiate}:\) videepktid
3:\(\textit{Insert}:\) videepkttp = \(l\_frame\), P_frame, B_frame
4:\(\textit{Insert}:\) I_DofDVNwhen forwardingguideopkt
5:\(\textit{Output}:\) Foruardwidepkt fromSVNtoDVN
6:ProcedureVideoDataForuarding\((p_{i}\), data)
7:\(\textit{IfvideorequestrecievedbySVNThen}\)
8:Obtainspeed, vehicle - id, road - id, direction, timestamp, position, Hmcountofp\({}_{i}\)(s)
9:\(\textit{ComputeVDRofp}_{i(s)}\textit{usingEq. }\) (1)
10:\(\textit{ComputeVT}\)\({}_{(C-NFV)}\textit{usingEq. }\) (7)
11:\(\textit{ComputeH}_{m}\textit{R}_{\textit{usingEq.