\documentclass[10pt,a4paper]{article}

% Packages
\usepackage{fancyhdr}           % For header and footer
\usepackage{multicol}           % Allows multicols in tables
\usepackage{tabularx}           % Intelligent column widths
\usepackage{tabulary}           % Used in header and footer
\usepackage{hhline}             % Border under tables
\usepackage{graphicx}           % For images
\usepackage{xcolor}             % For hex colours
%\usepackage[utf8x]{inputenc}    % For unicode character support
\usepackage[T1]{fontenc}        % Without this we get weird character replacements
\usepackage{colortbl}           % For coloured tables
\usepackage{setspace}           % For line height
\usepackage{lastpage}           % Needed for total page number
\usepackage{seqsplit}           % Splits long words.
%\usepackage{opensans}          % Can't make this work so far. Shame. Would be lovely.
\usepackage[normalem]{ulem}     % For underlining links
% Most of the following are not required for the majority
% of cheat sheets but are needed for some symbol support.
\usepackage{amsmath}            % Symbols
\usepackage{MnSymbol}           % Symbols
\usepackage{wasysym}            % Symbols
%\usepackage[english,german,french,spanish,italian]{babel}              % Languages

% Document Info
\author{otavio021}
\pdfinfo{
  /Title (mqtt-lightweight-messaging-protocol.pdf)
  /Creator (Cheatography)
  /Author (otavio021)
  /Subject (MQTT - Lightweight Messaging Protocol Cheat Sheet)
}

% Lengths and widths
\addtolength{\textwidth}{6cm}
\addtolength{\textheight}{-1cm}
\addtolength{\hoffset}{-3cm}
\addtolength{\voffset}{-2cm}
\setlength{\tabcolsep}{0.2cm} % Space between columns
\setlength{\headsep}{-12pt} % Reduce space between header and content
\setlength{\headheight}{85pt} % If less, LaTeX automatically increases it
\renewcommand{\footrulewidth}{0pt} % Remove footer line
\renewcommand{\headrulewidth}{0pt} % Remove header line
\renewcommand{\seqinsert}{\ifmmode\allowbreak\else\-\fi} % Hyphens in seqsplit
% This two commands together give roughly
% the right line height in the tables
\renewcommand{\arraystretch}{1.3}
\onehalfspacing

% Commands
\newcommand{\SetRowColor}[1]{\noalign{\gdef\RowColorName{#1}}\rowcolor{\RowColorName}} % Shortcut for row colour
\newcommand{\mymulticolumn}[3]{\multicolumn{#1}{>{\columncolor{\RowColorName}}#2}{#3}} % For coloured multi-cols
\newcolumntype{x}[1]{>{\raggedright}p{#1}} % New column types for ragged-right paragraph columns
\newcommand{\tn}{\tabularnewline} % Required as custom column type in use

% Font and Colours
\definecolor{HeadBackground}{HTML}{333333}
\definecolor{FootBackground}{HTML}{666666}
\definecolor{TextColor}{HTML}{333333}
\definecolor{DarkBackground}{HTML}{190204}
\definecolor{LightBackground}{HTML}{F7F7F7}
\renewcommand{\familydefault}{\sfdefault}
\color{TextColor}

% Header and Footer
\pagestyle{fancy}
\fancyhead{} % Set header to blank
\fancyfoot{} % Set footer to blank
\fancyhead[L]{
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{C}
    \SetRowColor{DarkBackground}
    \vspace{-7pt}
    {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent
        \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}}
    }
\end{tabulary}
\columnbreak
\begin{tabulary}{11cm}{L}
    \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{MQTT - Lightweight Messaging Protocol Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{otavio021} via \textcolor{DarkBackground}{\uline{cheatography.com/35559/cs/11177/}}}
\end{tabulary}
\end{multicols}}

\fancyfoot[L]{ \footnotesize
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{LL}
  \SetRowColor{FootBackground}
  \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}}  \\
  \vspace{-2pt}otavio021 \\
  \uline{cheatography.com/otavio021} \\
  \end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Published 15th March, 2017.\\
   Updated 15th March, 2017.\\
   Page {\thepage} of \pageref{LastPage}.
\end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Sponsor}}  \\
  \SetRowColor{white}
  \vspace{-5pt}
  %\includegraphics[width=48px,height=48px]{dave.jpeg}
  Measure your website readability!\\
  www.readability-score.com
\end{tabulary}
\end{multicols}}




\begin{document}
\raggedright
\raggedcolumns

% Set font size to small. Switch to any value
% from this page to resize cheat sheet text:
% www.emerson.emory.edu/services/latex/latex_169.html
\footnotesize % Small font.

\begin{multicols*}{3}

\begin{tabularx}{5.377cm}{x{1.59264 cm} x{3.38436 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Basic details and Terminoly}}  \tn
% Row 0
\SetRowColor{LightBackground}
MQTT Control Packet & A packet of information sent across the network \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
Application Message & The data carried by the protocol \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
Topic Name & A label attached to an Application Message that can be subscribed by clients \tn 
% Row Count 7 (+ 3)
% Row 3
\SetRowColor{white}
Topic Filter & An expression used to express interest in one or more topics (can use wildcards) \tn 
% Row Count 10 (+ 3)
% Row 4
\SetRowColor{LightBackground}
Session & Stateful interaction between a client and a server \tn 
% Row Count 12 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Note}}: TCP ports 1883 (default) and 8883 (TLS) are commonly used for MQTT.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{0.84609 cm} x{4.13091 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Data Representations}}  \tn
% Row 0
\SetRowColor{LightBackground}
Bits & Bits in a byte, from 7 (MSB) to 0 (LSB). \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\seqsplit{Integers} & Big-endian ordered, 16-bits \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\seqsplit{Strings} & UTF-8 strings, prefixed by its length \tn 
% Row Count 6 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{4.4793 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Quality of Service}}  \tn
% Row 0
\SetRowColor{LightBackground}
At Most Once & 0 \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
At Least Once & 1 \tn 
% Row Count 2 (+ 1)
% Row 2
\SetRowColor{LightBackground}
Exactly Once & 2 \tn 
% Row Count 3 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{p{0.4977 cm} p{0.4977 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Topic Names}}  \tn
% Row 0
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Must be at least 1 character long} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Case sensitive} \tn 
% Row Count 2 (+ 1)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{Can include spaces} \tn 
% Row Count 3 (+ 1)
% Row 3
\SetRowColor{white}
\mymulticolumn{2}{x{5.377cm}}{Name structured divided by slashes} \tn 
% Row Count 4 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Example}}: `/news/sports/europe`}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{1.05271 cm} p{0.4577 cm} x{3.06659 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{3}{x{5.377cm}}{\bf\textcolor{white}{Wildcards}}  \tn
% Row 0
\SetRowColor{LightBackground}
Multi level & \# & Used to match any number of levels within a topic tree, including the parent level itself. \tn 
% Row Count 4 (+ 4)
% Row 1
\SetRowColor{white}
Single level & + & Used to match a single level within a topic tree. \tn 
% Row Count 6 (+ 2)
% Row 2
\SetRowColor{LightBackground}
Reserved & \$ & Topics starting with the dollar sign ('\$') are reserved for server purposes and should not be used by clients. \tn 
% Row Count 11 (+ 5)
\hhline{>{\arrayrulecolor{DarkBackground}}---}
\SetRowColor{LightBackground}
\mymulticolumn{3}{x{5.377cm}}{{\bf{Notes}}: \newline Multi-level wildcard must always be the last symbol on the filter. Either on its own or preceded by the topic level separator. \newline  \newline Single-level: can be used in conjunction with the multi-level one.  \newline  \newline {\bf{Examples}}: \newline `+/sports/\#` - valid  \newline `sports+` - not valid}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}---}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{MQTT Control Packet Structure}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{The structure is formed by the aggregation of 3 sub-structures: fixed header, variable length header and payload.% Row Count 3 (+ 3)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{1.59264 cm} x{3.38436 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{MQTT Control Packet Structure: Fixed Header}}  \tn
% Row 0
\SetRowColor{LightBackground}
{\bf{Field}} & {\bf{Description}} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
Control Packet Type & 4 bit representation of the packet type. \tn 
% Row Count 3 (+ 2)
% Row 2
\SetRowColor{LightBackground}
Flags & 4 bit flags specific to each packet type. \tn 
% Row Count 5 (+ 2)
% Row 3
\SetRowColor{white}
Remaining Length & Number of bytes remaining in the packet. \tn 
% Row Count 7 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Note \#1}}: Control Packet Type and the Flags are stored in a single byte. \newline {\bf{Note \#2}}: The Remaining Length does not include the bytes used to encode itself}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{1.4931 cm} x{3.4839 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{MQTT Control Packet Structure: Variable Length}}  \tn
% Row 0
\SetRowColor{LightBackground}
{\bf{Field}} & {\bf{Description}} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
Packet Identifier & Used to establish a relationship between different MQTT Control Packets \tn 
% Row Count 4 (+ 3)
% Row 2
\SetRowColor{LightBackground}
Payload & A payload associated with the MQTT Control Packet \tn 
% Row Count 6 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{5.377cm}}{{\bf{Note}}: for the PUBLISH control packet, the payload is the application message.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{1.54287 cm} x{3.43413 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{MQTT Control Packets}}  \tn
% Row 0
\SetRowColor{LightBackground}
{\bf{Packet}} & {\bf{Name}} \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
CONNECT & Client request to connect \tn 
% Row Count 2 (+ 1)
% Row 2
\SetRowColor{LightBackground}
CONNACK & Connect ACK \tn 
% Row Count 3 (+ 1)
% Row 3
\SetRowColor{white}
PUBLISH & Publish message \tn 
% Row Count 4 (+ 1)
% Row 4
\SetRowColor{LightBackground}
PUBACK & Publish ACK \tn 
% Row Count 5 (+ 1)
% Row 5
\SetRowColor{white}
PUBREC & Publish received \tn 
% Row Count 6 (+ 1)
% Row 6
\SetRowColor{LightBackground}
PUBREL & Publish release \tn 
% Row Count 7 (+ 1)
% Row 7
\SetRowColor{white}
PUBCOMP & Publish complete \tn 
% Row Count 8 (+ 1)
% Row 8
\SetRowColor{LightBackground}
SUBSCRIBE & Client subscribe request \tn 
% Row Count 9 (+ 1)
% Row 9
\SetRowColor{white}
SUBACK & Subscribe ACK \tn 
% Row Count 10 (+ 1)
% Row 10
\SetRowColor{LightBackground}
UNSUBSCRIBE & Unsubscribe request \tn 
% Row Count 11 (+ 1)
% Row 11
\SetRowColor{white}
UNSUBACK & Unsubscribe ACK \tn 
% Row Count 12 (+ 1)
% Row 12
\SetRowColor{LightBackground}
PINGREQ & Ping request \tn 
% Row Count 13 (+ 1)
% Row 13
\SetRowColor{white}
PINGRESP & Ping response \tn 
% Row Count 14 (+ 1)
% Row 14
\SetRowColor{LightBackground}
DISCONNECT & Client disconnecting \tn 
% Row Count 15 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{CONNECT}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{{\bf{Important elements}}:  \newline % Row Count 1 (+ 1)
- Connect Flags: to specify the behavior of the connection. \newline % Row Count 3 (+ 2)
- Keep Alive: maximum time interval, in seconds, that can elapse between client transmission of control packets. \newline % Row Count 6 (+ 3)
{\bf{Connect Flags}}: \newline % Row Count 7 (+ 1)
- Clean Session: controls the lifetime of the session state (0 to resume state, 1 to discard previous state). \newline % Row Count 10 (+ 3)
- Will Flag: indicates that a will message is to be sent upon dirty client disconnection. \newline % Row Count 12 (+ 2)
- Will QoS: indicates QoS level for the will message. \newline % Row Count 14 (+ 2)
- Will Retain: indicates the retain policy for the will message. \newline % Row Count 16 (+ 2)
- Password: indicates whether (1) or not (0) a password must be present in the payload. \newline % Row Count 18 (+ 2)
- User Name: indicates whether (1) or not (0) a user name must be present in the payload. \newline % Row Count 20 (+ 2)
{\bf{Payload}}: \newline % Row Count 21 (+ 1)
Length prefixed fields whose presence is determined according to the value of flags in the variable header. The fields are, in order: client identifier, will topic, will message, user name, password.% Row Count 25 (+ 4)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{CONNACK}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{Sent by the server in response to a connection request sent by a client. The important elements on the packet structure are: connect acknowledgement flags and the connect return code.% Row Count 4 (+ 4)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{{\bf{Note}}: if a session is already present and the connection request does not have the clean session, the server must set the session present flag to 1.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{0.84609 cm} x{4.13091 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{CONNACK: Error Codes}}  \tn
% Row 0
\SetRowColor{LightBackground}
{\bf{Code}} & {\bf{Description}} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
0x00 & Connection accepted \tn 
% Row Count 3 (+ 1)
% Row 2
\SetRowColor{LightBackground}
0x01 & Connection refused (protocol version) \tn 
% Row Count 5 (+ 2)
% Row 3
\SetRowColor{white}
0x02 & Connection refused (identifier rejected) \tn 
% Row Count 7 (+ 2)
% Row 4
\SetRowColor{LightBackground}
0x03 & Connection refused (server unavailable) \tn 
% Row Count 9 (+ 2)
% Row 5
\SetRowColor{white}
0x04 & Connection refused (bad user/password) \tn 
% Row Count 11 (+ 2)
% Row 6
\SetRowColor{LightBackground}
0x05 & Connection refused (Unauthorized) \tn 
% Row Count 12 (+ 1)
% Row 7
\SetRowColor{white}
6-255 & Reserved \tn 
% Row Count 13 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{PUBLISH}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{This packet is used to transport application messages for a client to a server or from a server to a client. \newline % Row Count 3 (+ 3)
The important elements on the packet structure are: \newline % Row Count 5 (+ 2)
- DUP Flag: indicates whether this is the first time the message is being sent (0) or whether it might be a re-delivery attempt (1) of a previous message. \newline % Row Count 9 (+ 4)
- QoS Level: quality of service for an application message. \newline % Row Count 11 (+ 2)
- Retain Flag: indicates that the application message and its QoS must be stored in the server and delivered to future subscribers of that topic.% Row Count 14 (+ 3)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{5.377cm}}{{\bf{Note}}: The QoS flag affect how many messages can be stored on the server and sent to the client.}  \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Protocol Exchange: QoS 1}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{Client/Server protocol interaction: \newline % Row Count 1 (+ 1)
1. Client \{\{fa-arrow-right\}\} PUBLISH  \{\{fa-arrow-right\}\} Server \newline % Row Count 3 (+ 2)
2. Client \{\{fa-arrow-left\}\} PUBACK \{\{fa-arrow-left\}\} Server% Row Count 5 (+ 2)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Protocol Exchange: QoS 2}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{Client/Server protocol interaction: \newline % Row Count 1 (+ 1)
1. Client \{\{fa-arrow-right\}\} PUBLISH  \{\{fa-arrow-right\}\} Server \newline % Row Count 3 (+ 2)
2. Client \{\{fa-arrow-left\}\} PUBREC \{\{fa-arrow-left\}\} Server \newline % Row Count 5 (+ 2)
3. Client \{\{fa-arrow-right\}\} PUBREL  \{\{fa-arrow-right\}\} Server \newline % Row Count 7 (+ 2)
4. Client \{\{fa-arrow-left\}\} PUBCOMP \{\{fa-arrow-left\}\} Server% Row Count 9 (+ 2)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
\SetRowColor{DarkBackground}
\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Security}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{5.377cm}}{TLS is the recommended cryptographic protocol to be used with MQTT. Implementations should use port 8883.% Row Count 3 (+ 3)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\end{tabularx}
\par\addvspace{1.3em}


% That's all folks
\end{multicols*}

\end{document}