% Präambel
\documentclass[a4paper,12pt,parskip]{scrartcl}
\usepackage[ngerman]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\pagestyle{empty}
\usepackage{tikz, tikzpeople}

% document-Umgebung
\begin{document}
\begin{tikzpicture}
\node[draw] at (-4,3) {server 1};
\node[draw] at (0,3) {server 2};
\node[right,green!50!black] at (1.5,3) {resource (HTML-Datei)};
\draw[green!50!black,-Stealth] (1.6,3)--(1.1,3);
%\node[draw] at (4,3) {Server 3};
\node[draw] at (0,-0.4) {client};
\draw[purple,ultra thick] (0,-0.4) ellipse (12mm and 6mm); 
\node[purple,left] at (-1.2,-0.4) {\small host = Rechner im Netz};
\node[purple,right] at (1.2,-0.4) {mein Rechner};
\node[alice,mirrored,shirt=red,undershirt=teal,minimum size=1.8cm] 
at (-0.05,-2.4) {Ich};
\draw[-Stealth,teal!50!white,ultra thick] (-0.4,0.4)--(-0.4,2.4);
\draw[-Stealth,brown!60!white,ultra thick] (0.4,2.4)--(0.4,0.4);
\node[left] at (-0.4,1.4) {\textcolor{teal!70!white}{request}};
\node[right] at (0.4,1.4) {\textcolor{brown!80!white}{response}};
\node[align=left] at (-3.5,-2) {hier: client =\\web browser};
\end{tikzpicture}
\end{document}