## 4 Results and Discussion
### Examining the Robot's Processing Latency in Detail  
When comparing the robot's processing latency to the overall request duration and client-to-host round-trip latency, both the IK Solver and Move Request time appeared to comprise a significant portion of the overall latency only in the local wired LAN connection scenario. This was a consequence of the low network latency itself and not indicative of a high processing duration, however.  
The previous analysis did not make any comparisons between the individual latencies for each network configuration and presented conclusions only in relation to the client-to-host round-trip time and total request duration. Regarding the IK solver, some latency may be expected with the complex calculations dependent on arm position and movement request. In this section, we thus specifically compare the IK Solver latencies we observed across all four network topology scenarios, with the aim of determining whether there is any dependency between IK Solver latency and network complexity. Our resulting observations are shown in Figure 12. As can be observed, the average response times remain close to 4 ms across all four network scenarios, with occasional outliers reaching as high as 10 ms.  
Thus, the latency contributed by the IK Solver to the total request duration can be characterized as minimal, since even in the best-case scenario of a direct wired LAN connection, the IK Solver accounted for only 4 ms out of the measured 58 ms total request duration, and independent of the network topology in use between client and host. This is also true for any network access technology usage. Overall, we can observe that the latency distribution remains similar for each of the tested network scenarios. This latency will be  
\begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{2}{c}{**Round-Trip Time (ms)**} \\ \hline Mean & 240.769 \\ Median & 240.317 \\ Standard Dev. & 1.714 \\ Confidence Int. & 0.857 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Round-trip time of Transatlantic Network Connection scenario and Edge VPN.  
Figure 11: Box Plot of Latency from Transatlantic Network Connection scenario and Edge VPN.  
treated as static for the context of this paper, as the network has no effect on the robot's IK performance, and improvements to IK algorithms are outside the scope of this paper.  
Similarly, when we specifically evaluate the Move Request latency between the host and robot, shown in Figure 13, we observe a similar outcome compared to the IK solver latency. The important characteristic of this test is that it shows that the latency contribution of the Move Request never rises to a full millisecond, indicating minimal computations and network activity for this request within the ROS. Given that the latency also remains stable at or below 1 ms across all network scenarios we tested, the latency can be considered static, with minimal impact on the end-to-end latency of each test. We do note that we observed a larger number of outliers within the first tests, which is likely due to the larger number of measurements conducted in these tests.  
Since both the IK Solver time and Move Request duration have stable and similar contributions across all network tests we conducted, we can conclude the following:  
* They are independent of any client-to-host network topology considerations;
* They represent only a minimal portion of the overall total request duration.  
This signifies that the client's connectivity to the robotic control infrastructure has the largest impact on the reliability and usefulness of a telerobotic system. For future improvements to the operator's control loop, the utilization of loss-tolerant unidirectional packet flows, such as via UDP, may be beneficial. However, this presents its own set of challenges to control loop operations, which warrants further investigations, such as addressing the risk of erratic behavior from the robot during unstable network conditions.  
Figure 12: IK Solver latency comparison for all tested network scenarios.