Add explenation of partitions

diff --git a/a2/1cases.tex b/a2/1cases.tex
index 1bfdc39..9ffc07d 100644 (file)
--- a/a2/1cases.tex
+++ b/a2/1cases.tex
@@ -89,13 +89,14 @@ a feasible test suite the tests are divided into equivalence partitions. Below
 these partitions are given.
 
 \begin{enumerate}
-       \item \emph{Number of packets} in request~\footnote{A request is considered
-               establishing a connection (handshake) and a number of payload packets}
+       \item \emph{Number of segments} in request~\footnote{A request is
+               considered establishing a connection (handshake) and a number of
+               payload segments}
                \begin{enumerate}
-                       \item 0 payload packets
-                       \item 1 payload packet
-                       \item n=small payload packets
-                       \item n=big payload packets
+                       \item 0 payload segments
+                       \item 1 payload segments
+                       \item n=small payload segments
+                       \item n=big payload segments
                \end{enumerate}
        \item \emph{source port}
                \begin{enumerate}
@@ -107,11 +108,11 @@ these partitions are given.
                        \item Correct
                        \item Incorrect
                \end{enumerate}
-       \item Bits flipped in \emph{payload}
+       \item Bit errors in \emph{payload}
                \begin{enumerate}
                        \item Correct payload
-                       \item Payload with bit flips 
-                       \item Payload with odd number of bits flipped
+                       \item Payload with bit flips that do not show in checksum
+                       \item Payload with bit flips that do show in checksum
                \end{enumerate}
        \item \emph{checksum}
                \begin{enumerate}
@@ -129,24 +130,29 @@ these partitions are given.
 These partitions were chosen since they correspond to key parts of the TCP
 specification. 
 
-TCP segments are send over a TCP connection from a \emph{source} to a \emph{destination port}. Therefore segments which are received which have a 
+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
-as segments belonging to the connection. 
+as segments belonging to the connection by the SUT. 
 
 TCP uses a \emph{checksum} to catch any error introduced in headers, when this
-checksum does not match the actual computed checksum the packet should be
-disregarded.
+checksum does not match the actual computed checksum the SUT should
+disregard the received segment.
 
 The TCP checksum is also an inherently weak one, as it is simply the 
-bitwise negation of the addition in ones complement arithmetic 
+bitwise negation of the addition, in ones complement arithmetic, 
 of all 16 bit words in the header and data of the segment (excluding the
-header). Therefore any bit error where the ones complement value of one word
+checksum itself). Therefore any \emph{bit error} where the ones complement value
+of one word
 increases by one, and the value of another decreases by one, is undetected. 
 The SUT should exhibit the same behavior and accept packets where these type
-of bit error occur.
+of bit errors occur.
+
+TCP guarantees that segments are delivered in order,even when they are received
+\emph{out of order} and that missing segments are resend. The SUT should
+exhibit the same behavior. If segments are received out of order it should
+deliver them in order. Missing segments should be re-requested (by ACK-ing
+the correct sequence number).  
 
-\textbf{hier iets over waarom deze partities relevant zijn! Waarom odd en 
-even number of bits flipped bijv interessant?}
 \bigskip
 
 Partitions 2 to 6 are tested using pairwise testing to keep the number of test