X-Git-Url: https://git.martlubbers.net/?a=blobdiff_plain;f=1intro.tex;h=2e402b109e2c320965de16b8e70b12e84c440f88;hb=5859229ae0424ae7089eae4c220c078ccda1a271;hp=7da3120d6e08bad62084485335daf6cb38dc2044;hpb=555fdabeab56bb331d9155ace4f7c58631963898;p=tt2015.git

diff --git a/1intro.tex b/1intro.tex
index 7da3120..2e402b1 100644
--- a/1intro.tex
+++ b/1intro.tex
@@ -2,14 +2,16 @@
 %1, 2
 The objective of this document is to provide an approach for testing a
 particular implementation of \textit{Transmission Control Protocol} (TCP). TCP
-is a host-to-host protocol that provides a reliable communication. 
+is a host-to-host protocol that provides a reliable communication.
 
 This testing approach can be used by either an internal test team or an
 independent testing team. The test effort's goal is to become confident about
-the conformance of the implementation to the specification created by
+the conformance of an existing implementation to the specification created by
 \textit{The Internet Engineering Task Force}
 (IETF)\footnote{\url{http://www.ietf.org}} as document
-\textit{RFC793}~\cite{rfc793}.
+\textit{RFC793}~\cite{rfc793}. This document is explicitly \emph{not} intended
+to serve as guideline for testing during the development phase, but for testing
+conformity to the specification of an \emph{existing} implementation.
 
 \subsection{SUT}
 %3,4
@@ -17,8 +19,11 @@ The \textit{System under test} (SUT) is a
 Java\footnote{\url{http://www.java.com}} TCP driven echo server that executed
 on a virtualized Ubuntu system\footnote{\url{http://www.ubuntu.com}} running on
 the Linux kernel\footnote{\url{http://www.kernel.org}} version $3.13$. To test
-the error behaviour custom iptables output policies have to be
-set~\ref{listing:iptables}.
+the error behaviour custom iptables output policies have to be set
+Listing~\ref{listing:iptables}. This is needed because the kernel by default
+closes all connections from unknown sources and the manually created TCP
+packets used in testing the implementation are from a source unknown to the
+kernel.
 
 \begin{lstlisting}[label={listing:iptables},caption={settings iptables}]
 Chain OUTPUT (policy ACCEPT)
@@ -27,11 +32,22 @@ ACCEPT	tcp	--	anywhere	anywhere	tcp flags:PSH/PSH
 DROP	tcp	--	anywhere	anywhere	tcp flags:RST/RST
 \end{lstlisting}
 
-\subsection{Risks}
+\subsection{Risks} \label{sec:risks}
 %5. Risks
-Risks can be divided into two categories. Project risks and Product risks.
-\begin{itemize}
-	\item\textbf{Project Risks}\\
-	\item\textbf{Product Risks}\\
-\end{itemize}
+Risks can be divided into two categories. Project risks and product risks.
+Because an existing implementation is used the project risk are non applicable.
+Product risks even more so, since it is unknown if the product has been tested
+during development.
 
+The product risks for the SUT are significant because misbehaviour of the SUT
+could have potential large consequences. The key characteristics of TCP are
+integrity and reliability~\cite{rfc793}, these characteristics cease to exist
+when the implementation is faulty.
+
+Because TCP is a core functionality of a networking capable system it is
+crucial that the TCP implementation functions according to the specification.
+Several critical systems could rely on the correct functionality of the TCP
+implementation. A failure in the SUT could therefore have extensive
+consequences. Even more so since TCP is a computer-to-computer protocol, which
+leaves no room for ambiguity, which could be solved in a computer-to-human
+protocol.