update bib

[tt2015.git] / 1intro.tex

diff --git a/1intro.tex b/1intro.tex
index 76aa5d2..ea70356 100644 (file)
--- a/1intro.tex
+++ b/1intro.tex
@@ -6,10 +6,12 @@ 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} intented 
+to serve as guideline for testing during the development phase, but for testing 
+conformatiy to the specification of an \emph{existing} implementation. 
 
 \subsection{SUT}
 %3,4
@@ -18,7 +20,10 @@ 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}.
+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)
@@ -27,4 +32,25 @@ ACCEPT       tcp     --      anywhere        anywhere        tcp flags:PSH/PSH
 DROP   tcp     --      anywhere        anywhere        tcp flags:RST/RST
 \end{lstlisting}
 
+\subsection{Risks}
 %5. Risks
+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. 
+
+
+