# Evaluation of Modern Internet Transport Protocols over GEO Satellite Links
## 5 Experiments' Setup  
The testbed experiments were carefully designed to examine the interaction of the new HTTP protocols with congestion control over a typical satellite link. As explained in Section 3, one of the important features of HTTP/2 and HTTP/3 is the use of parallel streams over one transport connection. This can only be evaluated using web pages of complex structures and can only be measured using detailed application-level performance \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Machine** & **CPU Speed** & **Memory** & **Processer** & **Operating System** & **Software** \\ \hline Client & 1.9 GHz & 16 GB & Intel core i7-8650U & Windows 10 & FireFox Nightly V90.0a1 \\ Terminal & 1.9 GHz & 16 GB & Intel core i7-8650U & Linux kernel 5.4 & OpenSAND V5 Terminal \\ Satellite & 2.3 GHz & 8 GB & Intel core i3-7020U & Linux kernel 5.4 & OpenSAND V5 Satellite \\ Gateway & 2.67 GHz & 8 GB & Intel core i7 M620 & Linux kernel 5.4 & OpenSAND V5 Gateway \\ Server & 2.7 GHz & 16 GB & Intel core i7-7500U & Linux kernel 5.4 & OpenLightSpeed Web Server 1.7.12 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Software and hardware specifications of the testbed computers. Figure 5: The satellite link structure used in testbed. metrics. Therefore, we developed three HTML-based templates consisting of multiple embedded objects with different distributions of sizes and organization within the main HTML file. For the embedded objects, we produced eight JPEG images with varying sizes adapted in each HTML page to produce the desired total size of the web page. The distribution of objects in each page structure is listed in Table 3 and illustrated in Figure 6.  
The first template is a _single-object_ web page which consists of only one embedded object whose size is matched to the required size of the web page. The second template is a _uniform multi-object_ web page which contains eight objects of identical size such that their aggregate size is equal to the total web page size. The third one is a _triangular multi-object_ web page where the eight objects are organized inside the page according to a special order of their size. The first four objects are ordered in increasing size up to the middle of the web page then the four remaining object are ordered in decreasing size down to the end of the web page. The reason for this arrangement is to investigate the effect of parallel streams in HTTP/2 and HTTP/3 on the visual rendering of complex web pages. With parallel fetching of the embedded objects in such complex web pages, the user's perceived browsing performance of the web page will depend on the position of the largest objects in the page. If the largest object is embedded at the end of the web page, then the page would seem to load faster than if it was embedded at the beginning of the page because the smaller objects will load faster with parallel streams. The behavior will depend on the distribution of the embedded objects within the page; hence, we designed the above templates as a simplified representation of more realistic complex web pages. The testbed allows many evaluation scenarios each considering an HTTP variant running with a transport congestion algorithm. Each scenario can be run for different web  
Figure 6: The distribution of objects in each page structure used in experiments.