Merge branch 'tcpimprov' into releaseWithoutQA

# Conflicts:
#	res/sections/15-TCPVersions.tex

res/sections/15-TCPVersions.tex

@@ -2,7 +2,12 @@
 \section{TCP versions}
 
 \subsection{TCP Tahoe}
-Characteristics:
+One of the first protocols, very basic. It uses the Slow Start Phase and 
+AIMD, but it only relies on timeouts to detect losses, so no fast retransmit nor 
+fast recovery (it doesn't check for dupacks). At every loss, it always restart 
+from 1.
+
+\paragraph*{Characteristics}
 \begin{itemize}
   \item Standard TCP functions
   \item ``Slow'' start
@@ -15,7 +20,7 @@ \subsection{TCP Tahoe}
 \end{figure}
 
 \subsection{TCP Reno}
-Characteristics:
+\paragraph*{Characteristics}
 \begin{itemize}
   \item Fast Retransmit/Fast Recovery (3 dupAcks to recover one packet loss)
   \item TCP Reno can recover from one packet loss without having a time out
@@ -40,7 +45,9 @@ \subsubsection{TCP New Reno}
 \end{figure}
 
 \subsection{TCP SACK}
-SACK means \textit{Selective acknowledgment}.
+SACK means \textit{Selective acknowledgment}. This means that all ACKs are a
+little bigger but carry more information, they can give the sender the complete 
+picture.
 
 Returning ACKs declares which packets (even non contiguous) were received.
 All non-received packets can be retransmitted and so it recovers from multiple

res/sections/20-TCPVegas.tex

@@ -3,9 +3,7 @@ \subsection{TCP Vegas}
 \subsubsection{Congestion avoidance}
 
 Reaction to congestion episode, not to packets loss
-
 Modifications:
-
 \begin{itemize}
   \item Modified Congestion Avoidance
   \item Aggressive Retransmission
@@ -14,38 +12,38 @@ \subsubsection{Congestion avoidance}
 \end{itemize}
 
 Some definitions:
-
 \begin{itemize}
   \item \textbf{Throughput}: speed of transmission
   \item \textbf{Goodput}: speed of reception
 \end{itemize}
 
-Comparing expected and actual throughput:
+\noindent Comparing expected throughput\dots
+\begin{equation*}
+Expected\ throughput = \frac{window\ size}{RTT}
+\end{equation*}
+\dots and actual throughput:
+\begin{equation*}
+Actual\ throughput: \frac{actual\ transmitted\ amount}{RTT}
+\end{equation*}
 
+\noindent Monitor transmission rate:
 \begin{itemize}
-  \item \textbf{Expected throughput}: $\frac{window\_size}{RTT}$
-  \item \textbf{Actual throughput}: $\frac{actual\_transmitted\_amount}{RTT}$
+\item If $expected - \alpha < actual < expected$: Queues decreasing
+  $\rightarrow$ increase rate
+\item If $expected - \alpha < actual < expected - \beta$: Don’t do anything
+\item If $actual < expected - \beta$: Queues increasing $\rightarrow$ decrease
+  rate before packet drop (maybe there is a congestion in network or maybe the
+  connection is shared among other services) 
 \end{itemize}
 
-Monitor transmission rate: \\
-
-$\diamond$ If $expected - \alpha < actual < expected$:
-Queues decreasing $\rightarrow$ increase rate \\
-
-$\diamond$ If $expected - \alpha < actual < expected - \beta$:
-Don’t do anything \\
-
-$\diamond$ If $actual < expected - \beta$:
-Queues increasing $\rightarrow$ decrease rate before packet drop (maybe there
-is a congestion in network or maybe the connection is shared among other
-services) \\
-
-Thresholds of $\alpha (= \frac{1 pkts}{RTT})$ and $\beta (= \frac{3 pkts}{RTT})$ correspond to how many packets 
-Vegas is willing to have in queues.
-
-\begin{figure}[H]
+Thresholds of $\alpha (= \frac{1 pkts}{RTT})$ and
+$\beta (= \frac{3 pkts}{RTT})$ correspond to how many packets Vegas is willing
+to have in queues.
+\begin{figure}[t]
+  \centering
   \includegraphics[scale=0.35]{CAVegas}
   \caption{Vegas - Modified Congestion Avoidance}
+  \label{fig:tcpVegas:mca}
 \end{figure}