\begin{tikzpicture}[
mybox/.style={draw, rectangle, minimum width=4cm, minimum height=1 cm,font=\bfseries}
]

%\draw (0,0) rectangle (3cm, 1cm) {wat};

\node at (0, -0) [mybox] {Application};
\node at (0, -1) [mybox] {Transport};
\node at (0, -2) [mybox] {Internet};
\node at (0, -3)[mybox] {Network interface};

\end{tikzpicture}