# LaTeX table undefined control sequence

I know this is a very common occurence of the tables-related error, so thank you in advance for any help (I am getting very tired :-)).

I have this table that for some some reason refuses to compile. I think it did before, and I cannot see where the faulty change happened.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{multirow}
\usepackage{graphicx}
\usepackage{tabularx}
\usepackage[acronym]{glossaries}
\begin{document}
\newacronym{mno}{MNO}{Mobile Network Operator}
\newacronym{sdn}{SDN}{Software Defined Networking}
\newacronym{nfv}{NFV}{Network Function Virtualization}
\newacronym{vnf}{VNF}{Virtualized Network Function}
\newacronym{nve}{NVE}{Network Virtualization Environment}
\begin{table*}[t]
\centering
\caption{\gls{sdn} and \gls{nfv} multitenant environment fault management issues and consequences}
\label{TAB-issues}
\resizebox{\textwidth}{!}{

\begin{tabular}{c|l|l|l|l|l|}
\cline{2-6}
\multicolumn{1}{l|}{}                                           & \multicolumn{1}{c|}{\textbf{ISSUES}}                     & \textbf{\gls{sdn}?} & \multicolumn{1}{c|}{\textbf{\gls{nfv}?}} & \textbf{\begin{tabular}[c]{@{}l@{}}Multi-\\ tenant?\end{tabular}} & \multicolumn{1}{c|}{\textbf{CONSEQUENCES}}                               \\ \hline
\multicolumn{1}{|c|}{\multirow{3}{*}{\textbf{Scalability}}}     & 1) Huge requests to the \gls{sdn} controller             & \checkmark    &             & Limited \gls{sdn} controller capacity  \\ \cline{2-6}
\multicolumn{1}{|c|}{}                                          & 2) Huge number of faults and alarms                      & \checkmark    &    \checkmark                      & \checkmark                                                        & Alarms correlation and fault detection                                                    \\ \cline{2-6}
\multicolumn{1}{|c|}{}                                          & 3) A growing number of tenants and resources affectation &               &                                    &  \checkmark                                                       & Optimization of  resources allocation                                    \\ \hline
\multicolumn{1}{|c|}{\multirow{3}{*}{\textbf{Topology}}}        & 4) Dynamic topology                                      &               &                                    &                                                                   & Difficulty of modeling the network topology                              \\ \cline{2-6}
\multicolumn{1}{|c|}{}                                          & 5) Coexistence of Physical and virtual entities          &  \checkmark   &  \checkmark                        &  \checkmark                                                       & Virtual and physical faults dependencies                                 \\ \cline{2-6}
\multicolumn{1}{|c|}{}                                          & 6) Multi-tenants                                         &               &                                    &  \checkmark                                                       & Lack of network visibility                                               \\ \hline
\multicolumn{1}{|c|}{\multirow{2}{*}{\textbf{Security}}}        & 7) Attack on switches or controllers or control plane    & \checkmark    &                                    &                                                                   & Whole network disruption                                                 \\ \cline{2-6}
\multicolumn{1}{|c|}{}                                          & 8) Multi-tenant sharing the same infrastructure          &               &                                    &  \checkmark                                                       & Multi-tenants traffic isolation                                          \\ \hline
\multicolumn{1}{|c|}{\multirow{5}{*}{\textbf{Fault Tolerance}}} & 9) A single \gls{sdn} controller a single point of failure     & \checkmark    &                                    &                                                                   & \gls{sdn} controller failure implies the,whole network failure                 \\ \cline{2-6}
\multicolumn{1}{|c|}{}                                          & 10) Link failure                                         & \checkmark    &  \checkmark                        &                                                                   & Loss of network connection                                               \\ \cline{2-6}
\multicolumn{1}{|c|}{}                                          & 11) End to End service chain crash                       &               &  \checkmark                        &                                                                   & Rapid detection and recovery actions for clients services                \\ \cline{2-6}
\multicolumn{1}{|c|}{}                                          & 12) Physical and virtual faults                          & \checkmark    &  \checkmark                        &                                                                   & A physical failure may impact multiple virtual entities                  \\ \cline{2-6}
\multicolumn{1}{|c|}{}                                          & 13) Multi-tenants faults                                 &               &                                    & \checkmark                                                        & The necessity of tenants faults isolation and notification               \\ \hline
\multicolumn{1}{|c|}{\multirow{3}{*}{\textbf{Performance}}}     & 14) \gls{sdn} controller and switch performance                &\checkmark     &                                    &                                                                   & Choose the best network configurations to have a high network resilience \\ \cline{2-6}
\multicolumn{1}{|c|}{}                                          & 15) Running environments                                 &               &\checkmark                          &                                                                   & The performance of the \gls{vnf} depends on the running environment            \\ \cline{2-6}
\multicolumn{1}{|c|}{}                                          & 16) Migration of tenants applications or \gls{vnf}       &               & \checkmark                         &  \checkmark                                                       & Keep the same performance while migrating a tenant application or a \gls{vnf}  \\ \hline

\end{tabular}

}
\end{table*}
\end{document}


As you can see, the error is not the lack of packages or the acronyms (at list I think so), trying it with sharelatex or overleaf returns the error:

./main.tex:42: Undefined control sequence.
<argument> ... \gls {sdn} controller & \checkmark
& & Limited \gls {sdn} con...
l.42 }


Which is really hard to work around :-(.

Thanks for any inspiration on this!

• \checkmark is a macro that is not defined. Some packages define it, such as amssymb. – Steven B. Segletes Apr 30 '18 at 18:55
• In your code, \checkmark is undefined. You can load for example the amssymb package, that defines a \checkmark command. Despite of that, do not use resizebox as it leads to inconsistent ont sizes. – leandriis Apr 30 '18 at 18:55

As already mentioned in the comments, you recieve the error because the command \checkmark is not defined. By loading a packages that defined a \checkmark command, such as amssymb, one can make your code compilable.

Since you have a quite wide table, I recommend against using resizebox as it leads to illegible small and inconsistent font size. In the following MWE I have changed the general layout of the table to make it fit onto one page.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amssymb}
\usepackage{multirow}
\usepackage{graphicx}
\usepackage{tabularx}
\usepackage[acronym]{glossaries}
\usepackage{makecell}
\usepackage{rotating}
\usepackage{threeparttable}
\usepackage{booktabs}
\usepackage{ragged2e}
\usepackage{array}
\makeatletter
\newcolumntype{L}[1]{>{\RaggedRight\arraybackslash}p{#1}}
\newcolumntype{Z}{>{\RaggedRight\arraybackslash}X}

\begin{document}

\newacronym{mno}{MNO}{Mobile Network Operator}
\newacronym{sdn}{SDN}{Software Defined Networking}
\newacronym{nfv}{NFV}{Network Function Virtualization}
\newacronym{vnf}{VNF}{Virtualized Network Function}
\newacronym{nve}{NVE}{Network Virtualization Environment}

\begin{table}[t]
\centering
\caption{\gls{sdn} and \gls{nfv} multitenant environment fault management issues and consequences}
\label{TAB-issues}
\footnotesize
\renewcommand{\arraystretch}{1.25}
\begin{threeparttable}
\begin{tabularx}{\textwidth}{cr@{\hspace{1ex}}L{2.75cm}c@{\hspace{3pt}}c@{\hspace{3pt}}cZ}
\toprule
& \multicolumn{2}{l}{ISSUES}  & \gls{sdn}? & \gls{nfv}? & \makecell{Multi-\\tenant?} & CONSEQUENCES  \\
\midrule
\multirow{7}{*}{\rothead[c]{Scalability}}    & 1)& Huge requests to the \gls{sdn} controller             & \checkmark    &             & \tnote{*}  \\
& 2) & Huge number of faults and alarms     & \checkmark    &    \checkmark                      & \checkmark            & Alarms correlation and fault detection                                                    \\
& 3) & A growing number of tenants and resources affectation &               &                                    &  \checkmark   & Optimization of  resources allocation   \\
\midrule
\multirow{6}{*}{\rothead[c]{Topology}}        & 4)& Dynamic topology                                      &               &                                    &                                                                   & Difficulty of modeling the network topology                              \\
& 5) & Coexistence of Physical and virtual entities          &  \checkmark   &  \checkmark                        &  \checkmark                                                       & Virtual and physical faults dependencies                                 \\
& 6) & Multi-tenants                                         &               &                                    &  \checkmark                                                       & Lack of network visibility                                               \\
\midrule
\multirow{6}{*}{\rothead[c]{Security}}       & 7)& Attack on switches or controllers or control plane    & \checkmark    &                                    &                                                                   & Whole network disruption                                                 \\
& 8)& Multi-tenant sharing the same infrastructure          &               &                                    &  \checkmark                                                       & Multi-tenants traffic isolation                                          \\ \hline
\multirow{10}{*}{\rothead[c]{Fault Tolerance}} & 9)& A single \gls{sdn} controller a single point of failure     & \checkmark    &                                    &                                                                   & \gls{sdn} controller failure implies the,whole network failure                 \\
& 10)& Link failure                                         & \checkmark    &  \checkmark                        &                                                                   & Loss of network connection                                               \\
& 11) & End to End service chain crash                       &               &  \checkmark                        &                                                                   & Rapid detection and recovery actions for clients services                \\
& 12) & Physical and virtual faults                          & \checkmark    &  \checkmark                        &                                                                   & A physical failure may impact multiple virtual entities                  \\
& 13) & Multi-tenants faults                                 &               &                                    & \checkmark                                                        & The necessity of tenants faults isolation and notification               \\
\midrule
\multirow{9}{*}{\rothead[c]{Performance}}     & 14)& \gls{sdn} controller and switch performance                &\checkmark     &                                    &                                                                   & Choose the best network configurations to have a high network resilience \\
& 15) & Running environments                                 &               &\checkmark                          &                                                                   & The performance of the \gls{vnf} depends on the running environment            \\
& 16)& Migration of tenants applications or \gls{vnf}       &               & \checkmark                         &  \checkmark                                                       & Keep the same performance while migrating a tenant application or a \gls{vnf}  \\
\bottomrule
\end{tabularx}
\begin{tablenotes}
\item[*] Limited \gls{sdn} controller capacity
\end{tablenotes}
\end{threeparttable}
\end{table}

\end{document}


• Removed bold from column headings.
• Removed all vertical lines and replaced horizontal lines from the rules from the booktabs package that add an appropriate white space around them.
• Rotated the contents of the first column (Code for \rothead is taken from here: https://tex.stackexchange.com/a/429133/134144)
• Used threeparttable in order to put long text in the 'multitenant' column into a tablenote.
• Decreased distance between the checkmark containing columns in order to save some horizontal space.
• Added a new second column that contains the numbers. That way, the second and following lines of the corresponding texts are automatically indented.
• Used a fixed width column with raggedright alignment for the 'issues' column in order to allow for automated line breaks.
• sed a flexible width X column from the tabularx package in order to make the table as wide as the textwidth.
• Horizontally centered the checkmarks in their corresponding columns.
• ...

Here's a solution that (a) renders the table in landscape format and (b) allows automatic line breaking in two of the columns, thereby avoiding having to use \resizebox. Note also that I've simplified the material in the first column, mainly by getting of the \multirow "wrappers". (Oh, do make sure the amssymb package gets loaded, to access the \checkmark macro.)

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{geometry} % set page parameters suitably
\usepackage{amsmath,amssymb}
\usepackage{rotating,tabularx,ragged2e}
\newcolumntype{L}{>{\RaggedRight\arraybackslash}X}

\usepackage[acronym]{glossaries}
\begin{document}
\newacronym{mno}{MNO}{Mobile Network Operator}
\newacronym{sdn}{SDN}{Software Defined Networking}
\newacronym{nfv}{NFV}{Network Function Virtualization}
\newacronym{vnf}{VNF}{Virtualized Network Function}
\newacronym{nve}{NVE}{Network Virtualization Environment}

\begin{sidewaystable}

\caption{\gls{sdn} and \gls{nfv} multitenant
environment fault management issues and consequences}
\label{TAB-issues}

\small % 10% linear reduction in font size
\setlength\extrarowheight{2pt}
\setlength\tabcolsep{4pt} % default: 6pt

\begin{tabularx}{\textwidth}{|>{\bfseries}l|L|c|c|>{\centering}p{1.5cm}|L|}
\cline{2-6}
\multicolumn{1}{c|}{} & \textbf{Issues}
& \textbf{\gls{sdn}?} & \textbf{\gls{nfv}?}
& \textbf{Multi-tenant?} & \textbf{Consequences}
\\ \hline
Scalability
& 1) Huge requests to the \gls{sdn} controller
& \checkmark & & &
Limited \gls{sdn} controller capacity
\\ \cline{2-6}
& 2) Huge number of faults and alarms
& \checkmark & \checkmark & \checkmark
& Alarms correlation and fault detection
\\ \cline{2-6}
& 3) A growing number of tenants and resources
affectation
& & & \checkmark
& Optimization of resources allocation
\\ \hline
Topology
& 4) Dynamic topology
& & &
& Difficulty of modeling the network topology
\\ \cline{2-6}
& 5) Coexistence of Physical and virtual entities
& \checkmark & \checkmark & \checkmark
& Virtual and physical faults dependencies
\\ \cline{2-6}
& 6) Multi-tenants
& & & \checkmark
& Lack of network visibility
\\ \hline
Security
& 7) Attack on switches or controllers or control plane
& \checkmark & &
& Whole network disruption
\\ \cline{2-6}
& 8) Multi-tenant sharing the same infrastructure
& & & \checkmark
& Multi-tenants traffic isolation
\\ \hline
Fault Tolerance
& 9) A single \gls{sdn} controller a single point of failure
& \checkmark & &
& \gls{sdn} controller failure implies the whole network failure
\\ \cline{2-6}
& \checkmark & \checkmark &
& Loss of network connection
\\ \cline{2-6}
& 11) End to End service chain crash
& & \checkmark &
& Rapid detection and recovery actions for clients services
\\ \cline{2-6}
& 12) Physical and virtual faults
& \checkmark & \checkmark &
& A physical failure may impact multiple virtual entities
\\ \cline{2-6}
& 13) Multi-tenants faults
& & & \checkmark
& The necessity of tenants faults isolation and notification
\\ \hline
Performance
& 14) \gls{sdn} controller and switch performance
&\checkmark & &
& Choose the best network configurations to have a high network resilience
\\ \cline{2-6}
& 15) Running environments
& & \checkmark &
& The performance of the \gls{vnf} depends on the running environment
\\ \cline{2-6}
& 16) Migration of tenants applications or \gls{vnf}
& & \checkmark & \checkmark
& Keep the same performance while migrating a tenant application or a \gls{vnf}
\\ \hline
\end{tabularx}

\end{sidewaystable}
\end{document}