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%\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
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%\usepackage[english,german,french,spanish,italian]{babel}              % Languages

% Document Info
\author{Aelphi (Aelphi)}
\pdfinfo{
  /Title (network-02-osi-model.pdf)
  /Creator (Cheatography)
  /Author (Aelphi (Aelphi))
  /Subject (Network+ | 02.OSI Model Cheat Sheet)
}

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\fancyhead[L]{
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{C}
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    \vspace{-7pt}
    {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent
        \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}}
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\columnbreak
\begin{tabulary}{11cm}{L}
    \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Network+ | 02.OSI Model Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{Aelphi (Aelphi)} via \textcolor{DarkBackground}{\uline{cheatography.com/179727/cs/37397/}}}
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\fancyfoot[L]{ \footnotesize
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{LL}
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  \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}}  \\
  \vspace{-2pt}Aelphi (Aelphi) \\
  \uline{cheatography.com/aelphi} \\
  \end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Published 2nd March, 2023.\\
   Updated 28th March, 2023.\\
   Page {\thepage} of \pageref{LastPage}.
\end{tabulary}
\vfill
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  \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*}{2}

\begin{tabularx}{8.4cm}{p{0.76 cm} x{3.572 cm} x{3.268 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{3}{x{8.4cm}}{\bf\textcolor{white}{Layers and Wording}}  \tn
% Row 0
\SetRowColor{LightBackground}
7 & {\bf{Application}} & Data \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
6 & {\bf{Presentation}} & Data \tn 
% Row Count 2 (+ 1)
% Row 2
\SetRowColor{LightBackground}
5 & {\bf{Session}} & Data \tn 
% Row Count 3 (+ 1)
% Row 3
\SetRowColor{white}
4 & {\bf{Transport}} & \seqsplit{Segments/Datagram} \tn 
% Row Count 4 (+ 1)
% Row 4
\SetRowColor{LightBackground}
3 & {\bf{Network}} & Packets \tn 
% Row Count 5 (+ 1)
% Row 5
\SetRowColor{white}
2 & {\bf{Data-Link}} & Frames \tn 
% Row Count 6 (+ 1)
% Row 6
\SetRowColor{LightBackground}
1 & {\bf{Phyiscal}} & Bits \tn 
% Row Count 7 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}---}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2.96 cm} x{5.04 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{1. Physical}}  \tn
% Row 0
\SetRowColor{LightBackground}
Function & transmission of bits across network \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
\seqsplit{Representation} & Electrical voltage on wires -\textgreater{} 1 or 0 \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
- NRZ & 0 volt = {\bf{0}}, +/-5 volts = {\bf{1}} \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
- Transition Modulation & during a clock cycle, no change = 0, change = 1 \tn 
% Row Count 8 (+ 2)
% Row 4
\SetRowColor{LightBackground}
Topology & see cheatsheet 1/20 \tn 
% Row Count 9 (+ 1)
% Row 5
\SetRowColor{white}
Async comm. & use of {\emph{start bits}} and {\emph{stop bits}} to indicate when transm. occurs \tn 
% Row Count 12 (+ 3)
% Row 6
\SetRowColor{LightBackground}
Sync comm. & use of a reference clock to coordinate transm. \tn 
% Row Count 14 (+ 2)
% Row 7
\SetRowColor{white}
Broadband bandwith & divides bw into separate channels (ex Cable TV) \tn 
% Row Count 16 (+ 2)
% Row 8
\SetRowColor{LightBackground}
Baseband bandwith & uses different freqs on a cable \& a ref clock to coordinate transm. \tn 
% Row Count 19 (+ 3)
% Row 9
\SetRowColor{white}
Baseband Multixplexing & TDM, StatTDM, FDM are ways to allocate time slots and freqs over channels \tn 
% Row Count 22 (+ 3)
% Row 10
\SetRowColor{LightBackground}
ex & cables, radio freqs, devices (hubs, WAP, converters, ...) \tn 
% Row Count 25 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{1.2 cm} x{6.8 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{2. Data-Link}}  \tn
% Row 0
\SetRowColor{LightBackground}
MAC & 48-bit -\textgreater{} Network Interface Card (NIC) / 1st 24bits : manufacturer, 2nd 24bits : unique device value \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
LLC & {\emph{Logical Link Control}} \tn 
% Row Count 4 (+ 1)
% Row 2
\SetRowColor{LightBackground}
 & Reliable transmission of data \tn 
% Row Count 5 (+ 1)
% Row 3
\SetRowColor{white}
 & Segmentation \& addressing \tn 
% Row Count 6 (+ 1)
% Row 4
\SetRowColor{LightBackground}
 & Flow and Error control (checksum) \tn 
% Row Count 7 (+ 1)
% Row 5
\SetRowColor{white}
\seqsplit{Syncro} & Isochronous, Syncronous or Asyncronous \tn 
% Row Count 9 (+ 2)
% Row 6
\SetRowColor{LightBackground}
\seqsplit{Devices} & NIC, bridges, switches \tn 
% Row Count 11 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2.72 cm} x{5.28 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{3. Network}}  \tn
% Row 0
\SetRowColor{LightBackground}
Function & forwards traffic with logical adress \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
{\bf{Logical adress}} & IPv4, IPv6, IPX, AppleTalk \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
{\emph{Packet switching}} & divides data into packets and forward \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
{\emph{Circuit switching}} & dedicated comm link \tn 
% Row Count 8 (+ 2)
% Row 4
\SetRowColor{LightBackground}
{\emph{Message switching}} & divides data into storable messages which can be stored and forwarded later \tn 
% Row Count 11 (+ 3)
% Row 5
\SetRowColor{white}
{\bf{Routers}} & routing table based on IP adress, static or dynamic route \tn 
% Row Count 14 (+ 3)
% Row 6
\SetRowColor{LightBackground}
 & protocol RIP, OSPF, EIGRP \tn 
% Row Count 15 (+ 1)
% Row 7
\SetRowColor{white}
{\bf{Flow control}} & regulates data flow/speed \tn 
% Row Count 17 (+ 2)
% Row 8
\SetRowColor{LightBackground}
{\bf{Packet reordering}} & thanks to numbering and sequencing, packets can be sent across multiple routes \tn 
% Row Count 20 (+ 3)
% Row 9
\SetRowColor{white}
{\bf{ICMP}} & Internet Control Message Protocol \tn 
% Row Count 22 (+ 2)
% Row 10
\SetRowColor{LightBackground}
 & send error msg \& ops info about an IP, uses {\bf{ping}} and {\bf{traceroute}} \tn 
% Row Count 25 (+ 3)
% Row 11
\SetRowColor{white}
ex: & routers, multilayer switches, IPv4, IPv6, ICMP \tn 
% Row Count 27 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2.72 cm} x{5.28 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{4. Transport}}  \tn
% Row 0
\SetRowColor{LightBackground}
{\bf{TCP}} & Transmission Control Protocol \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
{\emph{connection oriented}} & reliable, resend lost segments, acknowlege (3-way handshake) \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{8.4cm}}{} \tn 
% Row Count 5 (+ 0)
% Row 3
\SetRowColor{white}
{\bf{UDP}} & User Datagram Protocol \tn 
% Row Count 6 (+ 1)
% Row 4
\SetRowColor{LightBackground}
{\emph{connectionless}} & ureliable, no retransmission, faster due to low overhead \tn 
% Row Count 9 (+ 3)
% Row 5
\SetRowColor{white}
{\bf{Windowing}} & adjust amount of data, based on retransmission reception quantity \tn 
% Row Count 12 (+ 3)
% Row 6
\SetRowColor{LightBackground}
{\bf{Buffering}} & router allocates memory to store segments \tn 
% Row Count 14 (+ 2)
% Row 7
\SetRowColor{white}
 & buffer overflow = segments dropped \tn 
% Row Count 16 (+ 2)
% Row 8
\SetRowColor{LightBackground}
ex: & TCP, UDP, WAN accelerators, load balancers, firewalls \tn 
% Row Count 19 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2.32 cm} x{5.68 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{5. Session}}  \tn
% Row 0
\SetRowColor{LightBackground}
{\bf{Function}} & setup a conversation \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
{\bf{Setting up}} & check credentials, session id, services needed and who starts \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
{\bf{Maintaining}} & transfer data, reestablish connection, acknowledge data recept° \tn 
% Row Count 8 (+ 3)
% Row 3
\SetRowColor{white}
{\bf{Tearing Down}} & on mutual agreement or other party disconnecting \tn 
% Row Count 10 (+ 2)
% Row 4
\SetRowColor{LightBackground}
ex: & {\bf{H.323/264}} (voice/video streaming), {\bf{NetBIOS}} (file exchange) \tn 
% Row Count 13 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2.48 cm} x{5.52 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{6. Presentation}}  \tn
% Row 0
\SetRowColor{LightBackground}
{\bf{Function}} & format data for readability, encrypt and secure data \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
{\bf{Data Formating}} & for compatibility purposes, readability (ASCII, JPG, etc) \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
 & compression, conversion \tn 
% Row Count 6 (+ 1)
% Row 3
\SetRowColor{white}
{\bf{Encryption}} & scrambles data, provide confidentiality (TLS) \tn 
% Row Count 8 (+ 2)
% Row 4
\SetRowColor{LightBackground}
ex: & programmation languages, text formats, pict extentions, protocols like TLS, SSL \tn 
% Row Count 11 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2.4 cm} x{5.6 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{7. Application}}  \tn
% Row 0
\SetRowColor{LightBackground}
{\bf{Function}} & interface user \textless{}-\textgreater{} computer \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
{\bf{App. Services}} & File transfer, sharing, email, remote access, NW mgmt, cl/srv processes \tn 
% Row Count 4 (+ 3)
% Row 2
\SetRowColor{LightBackground}
{\bf{Advertisement}} & service initiating a service offer to a NW \tn 
% Row Count 6 (+ 2)
% Row 3
\SetRowColor{white}
ex : & POP3, IMAP, SMTP / HTTP-S / DNS / FTP-S / Telnet, SSH / SNMP \tn 
% Row Count 9 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{x{2 cm} x{6 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{8.4cm}}{\bf\textcolor{white}{Encapsulation \& Decapsulation}}  \tn
% Row 0
\SetRowColor{LightBackground}
{\bf{Function}} & "envelopping" data with {\bf{headers}} \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
{\bf{PDU}} & Protocol Data Unit. ex: L3PDU-\textgreater{}Packet \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
\mymulticolumn{2}{x{8.4cm}}{{\bf{Flags}}} \tn 
% Row Count 5 (+ 1)
% Row 3
\SetRowColor{white}
SYN & initiates synchronization of connection \tn 
% Row Count 7 (+ 2)
% Row 4
\SetRowColor{LightBackground}
ACK & acknowledges during 3-WSH and packet reception \tn 
% Row Count 9 (+ 2)
% Row 5
\SetRowColor{white}
FIN & initates termination of connection \tn 
% Row Count 11 (+ 2)
% Row 6
\SetRowColor{LightBackground}
RST & when client or server receives a non expected packet \tn 
% Row Count 13 (+ 2)
% Row 7
\SetRowColor{white}
PSH & gives priority to data (for sender) \tn 
% Row Count 15 (+ 2)
% Row 8
\SetRowColor{LightBackground}
URG & gives priority to data (for recipient) \tn 
% Row Count 17 (+ 2)
% Row 9
\SetRowColor{white}
{\bf{MAC}} & phyiscal adress of a NIC \tn 
% Row Count 18 (+ 1)
% Row 10
\SetRowColor{LightBackground}
{\bf{EtherType}} & identify the protocol used (IPv4/v6) \tn 
% Row Count 20 (+ 2)
% Row 11
\SetRowColor{white}
\mymulticolumn{2}{x{8.4cm}}{{\emph{from L7 to L1}}} \tn 
% Row Count 21 (+ 1)
% Row 12
\SetRowColor{LightBackground}
at L4 & +TCP/UDP header (source \& dest ports) \tn 
% Row Count 23 (+ 2)
% Row 13
\SetRowColor{white}
at L3 & +IP header (source \& dest adresses) \tn 
% Row Count 25 (+ 2)
% Row 14
\SetRowColor{LightBackground}
at L2 & +MAC+LLC -{}-{}-{}- +FCS \tn 
% Row Count 26 (+ 1)
% Row 15
\SetRowColor{white}
at L1 & transmit L2 in bits (0 and 1) \tn 
% Row Count 27 (+ 1)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}


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

\end{document}