\input{lib/preamble.tex}

\begin{document}
\begin{tikzpicture}
  \node (Device) at (4,1) [component,external] { Gerät };
  \node (WSM) at (4,4) [component, inner sep=12px] { WSM };
  \node (Backend) at (4,7) [component,external] { Backend };
  \draw[very thick, rounded corners=6px] (0,2) rectangle (8,6) ++(0, 0.1) node [label, anchor=south east] { \large Heimdall };
  \draw (Device) edge [<->] node (Websocket) {} (WSM);
  \draw (WSM) edge [->, bend left=10] (Backend) (Backend) edge [->, response, bend left=10] (WSM);
  \node at (5.5,4.5) [stickynote, callout absolute pointer=(WSM.20), anchor=south west] { Web Socket\\Manager };
  \node at (2.5,3.5) [stickynote, callout absolute pointer=(Websocket.center), anchor=north east] { Websocket-\\Verbindung };
\end{tikzpicture}
\end{document}