\begin{tikzpicture}[scale=0.30]
	\sffamily
	\foreach \x in {0,7,8,15,16,31} % {0,...,32}
		\node at (\x+0.5,20.5) {\scriptsize \x};
%	\foreach \x in {0,...,31}
%		\node at (\x+0.5,13.5) {\scriptsize \x};
	\foreach \x in {0,8,16,32} % {0,...,32}
		\draw[thick] (\x,20) -- (\x,21);
	\foreach \x in {0,...,32}
		\draw[thick] (\x,14) -- (\x,20);
%	\foreach \x in {0,...,32}
%		\draw[thick] (\x,13) -- (\x,14);
	\node[thick] (bit1) at (-0.6,20.5) {\scriptsize bit};
%	\node[thick] (bit2) at (-0.6,13.5) {\scriptsize bit};
		
\iffalse
	\draw [<->, thick] (-0.6, 19.9) -- (-0.6,15.1);
	\draw [thick] (-1, 20) -- (-0.1,20);
	\draw [thick] (-1, 15) -- (-0.1,15);
	\node[fill=white] at (-1.1,17.5) {\tiny 20 bytes};
\fi
	\foreach \y/\v in {0,4,8,12,16,20}
		\node at (-0.6,{19.5-(\v / 4)}) {\scriptsize \v};

	\filldraw[thick,draw=black, fill=white] (0,20) rectangle (4,19); \node (mode) at (2,19.5) {\scriptsize version};
	\filldraw[thick,draw=black, fill=white] (4,20) rectangle (8,19); \node (mode) at (6,19.5) {\scriptsize len};
%	\draw[thick, draw=black, fill=white] (8,20) rectangle (16,19); \node (stratum) at (11.5,19.5) {\scriptsize type of service (TOS)};
	\draw[thick, draw=black, fill=white] (8,20) rectangle (16,19); \node (stratum) at (11.5,19.5) {\scriptsize TOS};
	\draw[thick, draw=black, fill=white] (16,20) rectangle (32,19); \node (li) at (24,19.5) {\scriptsize full length of packet};
	\filldraw[thick,draw=black, fill=white] (0,19) rectangle (16,18); \node (mode) at (8,18.5) {\scriptsize identification};
%	\draw[thick, draw=black] (16,19) rectangle (19,18); \filldraw[white] (16.5,18.43) rectangle (19,18.88); \node [](li) at (17.5,18.67) {\tiny IP flags}; \node at (16.5,18.25) {\tiny x};\node at (17.5,18.25) {\tiny D};\node at (18.5,18.25) {\tiny M};
	\draw[thick, draw=black] (16,19) rectangle (19,18); \filldraw[white] (16.5,18.43) rectangle (19,18.88); \node at (16.5,18.5) {\scriptsize X};\node at (17.5,18.5) {\scriptsize D};\node at (18.5,18.5) {\scriptsize M};
	\draw[thick, draw=black, fill=white] (19,19) rectangle (32,18); \node (li) at (24,18.5) {\scriptsize fragment Offset};
	\filldraw[thick,draw=black, fill=white] (0,18) rectangle (8,17); \node (mode) at (4,17.5) {\scriptsize time to live (TTL)};
	\draw[thick, draw=black, fill=white] (8,18) rectangle (16,17); \node (stratum) at (11.5,17.5) {\scriptsize protocol};
	\draw[thick, draw=black, fill=white] (16,18) rectangle (32,17); \node (li) at (24,17.5) {\scriptsize header checksum};
	\filldraw[thick,draw=black, fill=white] (0,17) rectangle (32,16); \node (mode) at (16,16.5) {\scriptsize source IP address};
	\filldraw[thick,draw=black, fill=white] (0,16) rectangle (32,15); \node (mode) at (16,15.5) {\scriptsize destination IP address};
	\draw[thick,draw=black, fill=white] (0,15) rectangle (32,14);
%	\draw[thick,draw=black, fill=white] (0,15) rectangle (31.5,14);
%	\draw[fill=white, draw=white] (31.4,15) rectangle (31.6,16);
%	\draw[thick]  (31.5,14.97)  decorate [decoration=saw] { -- (31.5,14.02)};
	\node (mode) at (16,14.5) {\scriptsize IP options (variable length)};

	\filldraw[thick,draw=black, fill=white] (0,12) rectangle (32,14); \node (mode) at (16,13) {\scriptsize payload};

\end{tikzpicture}