\begin{tikzpicture}[thick, node distance=1em]
	
	% Level 1 switches
	\foreach \n in {0,...,1}{
		\node (level 1 \n) at (2.0cm + \n*4*1.5cm,3.0) [draw,rectangle,inner sep=0.8em] {Switch};
	}
	
	% Level 2 switches
	\foreach \n in {0,...,3}{
		\node (level 2 \n) at (0.75cm + \n*2*1.5cm,1.5) [draw,rectangle,inner sep=0.5em] {Switch};
		
		\draw [thick] (level 2 \n) to (level 1 0);
		\draw [thick] (level 2 \n) to (level 1 1);
	}
	
	% Nodes
	\foreach \n in {0,...,7}{
		\node (node \n) at (\n*1.5cm,0) [draw,circle,inner sep=0.1em] {Node};
		
		\pgfmathtruncatemacro{\switch}{\n/2}
		\draw [thin] (node \n) to (level 2 \switch);
	}
	
\end{tikzpicture}
