\begin{tikzpicture}[
mybox/.style={
	draw,
	rectangle,
	minimum height=1 cm,
	anchor=west,
	align=center,
	font=\bfseries}
]

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

\node at (0 cm, 0 cm) [mybox, minimum width=2cm, text width=1.7cm] {Frame header};
\node at (2 cm, 0 cm) [mybox, minimum width=6cm] {Frame data};
\node at (8 cm, 0 cm) [mybox, minimum width=2cm, text width=1.7cm] {Frame footer};

\node at (2 cm, 1.1 cm) [mybox, minimum width=2cm] {IP header};
\node at (4 cm, 1.1 cm) [mybox, minimum width=4cm] {IP Data};

\node at (4 cm, 2.2 cm) [mybox, minimum width=2cm, text width=1.7 cm] {UDP header};
\node at (6 cm, 2.2 cm) [mybox, minimum width=2cm, text width=1.7 cm] {UDP Data};

\node at (6 cm, 3.3 cm) [mybox, minimum width=2cm, text width=1.7 cm] {Data};

\end{tikzpicture}