这种框图该怎么画？

Question 1

虽然jakun已经提供了解决方案，但这是一个替代解决方案。

Source并Destination可以添加为最大fit节点的标签：

  \node[bigbox, label=source] (O) [fit = (A) (F) (N)] {};

（我简化了fit参数，仅包含重要节点，而不是全部）

作为替代方案jakun's transform canvas（我不知道），您可以使用：

\draw[<-] ([yshift=8mm]O.south east) coordinate (aux) -- node[below] {Ack} (aux-|Ad.west);

或者使用calctikzlibrary：

\draw[->] ($(O.north east)!.2!(O.south east)$) -- ($(Ad.north west)!.2!(Ad.south west)$);

完整的代码可能是：

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows, positioning, backgrounds, fit}
\usepackage{lmodern}

\begin{document}

    \begin{figure*}
\begin{center}
\begin{tikzpicture}[shorten >=1pt,node distance=3.7cm,>=stealth',bend angle=45, font=\sffamily]
\tikzstyle{block} = [rectangle, draw=black, thick, text width=0.5em, text centered, minimum height=1em]
\tikzstyle{block1}=[rectangle, draw=black, thick, text width=2em, text centered,minimum height=3em]
\tikzstyle{block2}=[rectangle, draw=black, thick, text width=4em, text centered,minimum height=2em]
\tikzstyle{block3}=[rectangle, draw=black, thick, text width=8em, text centered,minimum height=5em]
\tikzstyle{bigbox} = [draw=black,thick, rectangle]
\tikzstyle{triple}=[draw, anchor=text, thick, rectangle split,rectangle split parts=3]
\tikzstyle{double}=[draw, anchor=text, thick, rectangle split,rectangle split parts=2]
%\tikzstyle{textbox} = {draw, fill=white, thick,text=black}
\node[block] (A) {};
\node[block] (B) [below=0.2cm of A] {}; 
\node[block] (C) [below=0.2cm of B] {}; 
\node[block] (D) [below=0.2cm of C] {}; 
\node[block] (E) [below=0.2cm of D] {}; 
\node[block] (F) [below=0.2cm of E] {}; 
\node[block] (G) [right=0.4cm of C] {};
\node[block] (H) [right=0.1cm of G] {};
\node[block] (I) [right=0.1cm of H] {};
\node[block] (J) [right=0.3cm of I] {};
\node[block] (K) [right=0.1cm of J] {};
\node[block] (L) [right=0.1cm of K] {};

\node[block] (P) [right=2cm of L] {};
\node[block] (Q) [right=0.1cm of P] {};
\node[block] (R) [right=0.1cm of Q] {};
\node[block] (S) [right=0.3cm of R] {};
\node[block] (T) [right=0.1cm of S] {};
\node[block] (U) [right=0.1cm of T] {};
\node[block] (X) [right=0.3cm of U] {};
\node[block] (Y) [above=0.2cm of X] {};
\node[block] (Z) [above=0.2cm of Y] {};
\node[block] (Aa) [below=0.2cm of X] {};
\node[block] (Ab) [below=0.2cm of Aa] {};
\node[block] (Ac) [below=0.2cm of Ab] {};

\begin{pgfonlayer}{background}
  \node[bigbox] (M) [fit = (G) (H) (I)] {};     
  \node[bigbox] (N) [fit = (J) (K) (L)] {};
  \node[bigbox] (V) [fit = (P) (Q) (R)] {};
  \node[bigbox] (W) [fit = (S) (T) (U)] {};

  \node[bigbox, label=source] (O) [fit = (A) (F) (N)] {};
  \node[bigbox, label=destination] (Ad) [fit = (Z) (Ac) (V)] {};
\end{pgfonlayer}
\path (M.south) -- node[below] {Packets} (N.south);
\path (V.south) -- node[below] {Packets} (W.south);

\draw[->] ([yshift=-8mm]O.north east) coordinate (aux) -- (aux-|Ad.west);
\draw[<-] ([yshift=8mm]O.south east) coordinate (aux) -- node[below] {Ack} (aux-|Ad.west);
\end{tikzpicture}
\caption{Proposed Framework} \label{fig1}
\end{center}
\end{figure*}
\end{document}

更新：借助一些matrix节点可以简化代码：

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows, positioning, fit, matrix}
\usepackage{lmodern}

\begin{document}

\begin{figure*}
\begin{center}
\begin{tikzpicture}[%
    shorten >=1pt,
    shorten <=1pt,
    >=stealth',
    font=\sffamily,
    block/.style = {rectangle, black, thick, text width=0.5em, text centered, minimum height=1em},
    packet/.style={draw, thick, matrix of nodes, nodes in empty cells, nodes={block, draw}},
    bigbox/.style={rectangle, draw, thick}
    ]

\matrix (A1) [packet, draw=none, row sep=2mm]{ \\ \\ \\ \\ \\ \\ };
\matrix (B1) [packet, column sep=2mm, right=3mm of A1]{ & & \\};
\matrix (C1) [packet, column sep=2mm, right=1mm of B1]{ & & \\};
\node[bigbox, label=Source] (D1) [fit = (A1) (C1)] {};

\matrix (C2) [packet, column sep=2mm, right=2cm of C1]{ & & \\};
\matrix (B2) [packet, column sep=2mm, right=1mm of C2]{ & & \\};
\matrix (A2) [packet, draw=none, row sep=2mm, right=3mm of B2]{ \\ \\ \\ \\ \\ \\ };
\node[bigbox, label=Destination] (D2) [fit = (A2) (C2)] {};

\path (B1.south) -- node[below] {Packets} (C1.south);
\path (B2.south) -- node[below] {Packets} (C2.south);

\draw[->, thick] ([yshift=-8mm]D1.north east) coordinate (aux) -- (aux-|D2.west);
\draw[<-, thick] ([yshift=8mm]D1.south east) coordinate (aux) -- node[below] {Ack} (aux-|D2.west);
\end{tikzpicture}
\caption{Proposed Framework} \label{fig1}
\end{center}
\end{figure*}
\end{document}

Answer

虽然jakun已经提供了解决方案，但这是一个替代解决方案。