\end{enumerate}
These partitions were chosen since they correspond to key parts of the TCP
-specification.
+specification. A single request consists of a number of packets that sent a
+to the \emph{echo-server} and back. The TCP specification state that such a
+transaction requires the following messages.
+
+\begin{center}
+ Script $-$ SYN $A$ $\rightarrow$ SUT \\
+ Script $\leftarrow$ SYN-ACK $(A+1)$ $B$ $-$ SUT \\
+ Script $-$ ACK $(A+1)$ $(B+1)$ $\rightarrow$ SUT \\
+ Script $-$ ACK-PUSH $(A+1)$ $(B+2)$ \emph{msg} $\rightarrow$ SUT \\
+ Script $\leftarrow$ ACK $(A+2+msg_{length})$ $(B+3)$ $-$ SUT \\
+ Script $\leftarrow$ ACK-PUSH $(A+2+msg_{length})$ $(B+3)$ \emph{msg} $-$ SUT
+\end{center}
+
+%
+% één na laatste packket, moet dit B+3 of B+2 zijn?
+%
TCP segments are send over a TCP connection from a \emph{source} to a \emph{destination port}. Therefore segments which are received that have a
source or destination port set to an incorrect value should not be regarded