## 7 Performance Evaluation of Multicast R-GOOSE over Public WAN
### Results and Discussion  
Our test is not focused on the delay of a particular message. Instead, the objective is to find out the average value of latency over a period of time. Thus, multicast R-GOOSE messages are retransmitted every 3 s (by C application) for the duration of about one day. These retransmissions are sent within different communication configurations, as defined in Table 6, and are received and recorded by Wireshark via the lab-restricted-measurement method. In the context of measurements made in this paper, using the lab-restricted-measurement method does not have any practical impact on the results because the measurement accuracy difference between the lab-restricted-measurement method and field-capable-measurement method is negligible in the time scale that we are measuring. Figure 21: Sending time and arrival time of R-GOOSE message in Wireshark. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Communication**} & \multirow{2}{*}{**Architecture**} & \multirow{2}{*}{**Configuration**} & \multicolumn{5}{c}{**Statistical Analysis Results**} & \multicolumn{3}{c}{**Communication-Based Protection**} \\ \cline{5-10}  & & & & \multicolumn{2}{c}{**Statistical Analysis Results**} & \multicolumn{3}{c}{**Logic Selectivity**} \\  & & & & & & & & & (100 ms) & \\ \cline{5-10}  & & & **1 st Centile** & **Mean Delay** & **99h Centile** & **Packet Loss** & **Total Number** & **Communication** & **Communication** \\  & & & **(ms)** & **(ms)** & **(ms)** & **(s)** & **(s)** & **(s)** & **(s)** & **(s)** \\ \hline \multirow{10}{*}{**4C**} & \multirow{5}{*}{GRE} & R,COOSE\_over, UPC & 23.2 & 66.3 & 155.5 & 0.000 & 28.746 & 88.0 & 100.0 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 23.6 & 71.6 & 149.8 & 0.000 & 27,440 & 81.7 & 100.0 \\ \cline{5-10}  & & R,COOSE\_over, UPC & 23.5 & 70.7 & 156.6 & 0.000 & 28,996 & 82.5 & 100.0 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 24.1 & 73.5 & 152.2 & 0.000 & 29,411 & 80.0 & 100.0 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 21.0 & 72.4 & 166.9 & 0.000 & 28,605 & 77.2 & 100.0 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 22.0 & 80.7 & 164.5 & 0.000 & 28,928 & 70.8 & 100.0 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 24.7 & 86.8 & 172.9 & 0.000 & 28,890 & 64.3 & 100.0 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 24.1 & 83.2 & 185.7 & 0.000 & 28,495 & 68.0 & 100.0 \\ \hline \multirow{10}{*}{**5C**} & \multirow{5}{*}{GRE} & R,COOSE\_over, UPC & 14.5 & 162.3 & 340.2 & 0.000 & 27,466 & 33.2 & 89.7 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 14.6 & 161.7 & 340.1 & 0.003 & 28,974 & 33.5 & 89.8 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 15.3 & 126.1 & 332.6 & 0.000 & 27,467 & 52.9 & 93.6 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 15.1 & 162.6 & 335.6 & 0.037 & 27,074 & 32.9 & 89.6 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 14.8 & 160.6 & 337.0 & 0.007 & 28,835 & 34.3 & 89.6 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 14.9 & 157.8 & 336.3 & 0.000 & 28,779 & 35.5 & 90.2 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 23.3 & 164.5 & 344.0 & 0.000 & 28,671 & 33.4 & 88.3 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 23.3 & 166.7 & 345.3 & 0.000 & 28,664 & 32.7 & 87.7 \\ \cline{5-10}  & & Stagnel, R,COOSE\_over, UPC & 23.3 & 166.7 & 345.3 & 0.000 & 28,664 & 32.7 & 87.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Statistical analysis of the measurements data. These recorded messages are saved as Wireshark files, and these are used as the references for measuring the R-GOOSE communication latency and packet losses. To this end, R-GOOSE contents are exported from the Wireshark files and saved as CSV (Comma Separated Values) files. These files are then imported into MATLAB for statistical analysis. This procedure is used to calculate the latency values for the R-GOOSE messages in each configuration in Table 6. This also allows the packet loss for the R-GOOSE messages retransmitted within a one-day period to be calculated. Each unique R-GOOSE message has a unique SPDU number.