How to draw 3 components diagram?

I would like to draw the following figure in LaTeX, but I am unable to get any satisfying result with the packages tikz, smartidagram or even graphicx.

I am grateful for any tip and suggestion.

Thank you! • Welcome to TeX.SX! Please help us help you and add a minimal working example (MWE) that illustrates your problem. Reproducing the problem and finding out what the issue is will be much easier when we see compilable code, starting with \documentclass{...} and ending with \end{document}. Note this is a Q&A site, not a please do this for me service. What do you have so far, even though you already said that you tried different options. Nov 20 '18 at 16:40

tikz-cd is a convenient package for drawing commutative diagrams relatively easily. It provides macros to facilitate the creation of diagrams instead of using tikz directly which can be quite cumbersome.

\documentclass[12pt,a4paper]{article}
\usepackage{tikz-cd,amsmath}
\begin{document}

\begin{tikzcd}[column sep=small]
& \mathrm{M/M/1} \arrow[dl,leftrightarrow] \arrow[dr,leftrightarrow] & \\
\left.\begin{array}{r@{}}
\lambda_k = \lambda\$.5em] \mu_k = \mu \end{array}\right\} \arrow[rr,leftrightarrow] & & \left\{\begin{array}{@{}l} A(t) = 1-e^{-\lambda t}\\[.5em] B(x) = 1-e^{-\mu x} \end{array}\right. \end{tikzcd} \end{document} Welcome to TeX.SE! There are zillions of ways of producing something of this type. Here is one. \documentclass{article} \usepackage{amsmath} \usepackage{tikz} \usetikzlibrary{tikzmark} \begin{document} \[\begin{array}{rcl} & \tikzmarknode{M}{M}/M/\tikzmarknode{1}{1} & \\[8mm] \left.\begin{array}{r} \mathstrut\lambda_k =\tikzmarknode{l}{\lambda}\\ \mathstrut\mu_k =\mu \end{array}\!\right\}\tikzmarknode{ls}{\mathstrut} & \quad \quad & \tikzmarknode{rs}{\mathstrut} \left\{\!\begin{array}{l} \mathstrut\tikzmarknode{A}{A}(t) =1-\mathrm{e}^{-\lambda t}\\ \mathstrut B(t) =1-\mathrm{e}^{-\mu t} \end{array}\right.\end{array}$
\begin{tikzpicture}[remember picture,overlay]
\draw [latex-latex] (M) -- (l);
\draw [latex-latex] (1) -- (A);
\draw [latex-latex] (ls) -- (rs);
\end{tikzpicture}%
\end{document} I really hope you find enough motivation and patience to explore these options by yourself. You'll see it's worth it.