## 3 Road-Based Multi-Metric Forwarder Evaluation Scheme
### Information Collection Stage
#### 3.1.3 Hello Message Receive Rate  
The hello message receive rate has been employed to justify playback freezes with startup delay, which is considered as another important parameter for achieving quality video streaming. The essence of employing this metric is based on consideration of the nature of data that is being transmitted from source to destination. However, the two different parameters considered in the previous subsections are very important but might not be adequate, because they may not guarantee the quality of the video. Minimum arrival time is required for better quality display if there is a delay in single packet most especially the I-frame, the whole of the previous packet might not be meaningful after the display. Thus, there is a need for a parameter that considers the video characteristics of the playback freezes. Despite estimating the VDR for selecting NFV that is within a particular road and estimating the vehicle trajectory towards the destination. There is still a need to take advantage of the Hello message Receive rate (\(\rm{H_{m}R_{r}}\)) of each of the C-NFV in order to know the C-NFV has greater link connectivity with PFV. This will enable the estimation of how fast the C-NFVs can forward or deliver a video stream to destination.  
The startup delay in video streaming is the latency between when the video packet is received to the time it starts streaming. The time when streaming starts depends on the number of video frames received within a specific period. The faster the video frames are delivered the faster the startup with lower delay. A lower startup delay translates to a better quality video. The playback freezes occur when there is no ample amount of video content in the buffer while the display has already started. This leads to breaking or stopping of streaming during video display. Streaming with zero or few playbacks freezes also translate to quality of the video streaming. Thus, both the playback freezes and the startup delay are defined as a function of delay in transmission from one vehicle to another.  
The number of the received hello message from each of the neighbor vehicles is calculated. Every vehicle stores the number of hello messages received from each of its neighbors to the TNI. The PFV select the vehicle with the highest number of hello messages at the time of video forwarding. The vehicle with the highest hello message signifies that there is higher link connectivity with the PFV. Therefore, the following Equation (10) is employed to compute the number of hello message received rate of each C-NFV. The summation of all hello messages per C-NFV is compared with that of the other C-NFVs and then the C-NFV that has forwarded the highest hello message is chosen. The C-NFV with the highest value of \(\rm{H_{m}R_{r}}\) is considered as a good C-NFV. The \(\rm{H_{m}R_{r}}\) is computed to select two Relay Vehicle Node (RVN) at the SVN and the intermediary vehicles compute the \(\rm{H_{m}R_{r}}\) to select single NFV up to the DVN.  
\[\rm{T_{H_{m}R_{r}}}=\sum_{i=1}^{n}H_{m}R_{r} \tag{10}\]  
Here, it is assumed that the C-NFV with the highest hello message has a greater connectivity. Thus, the delay in video delivery is minimal, which lead to zero or fewer freezes with lower startup delay. Consequently, it helps in selecting an optimal vehicle that improves the quality of the video streaming transmission. The \(\rm{T_{H_{m}R_{r}}}\) is the total number of the received hello message by the PFV. The next subsection discusses the accessible bandwidth estimation.