\chapter{Introduction}

In the late seventies and the early eighties of the last century, the development of the personal computer revolutionized the industry and introduced computing technology
to the general business as well as to the private market. Through continued technological progress during the following two decades, computer systems continually improved 
and became smaller and more powerful up to a point where it was possible for these devices to be carried around. Since that time mobile devices are on the advance. With processing power not being an issue, energy consumption and wireless communication became the new barriers for technological advancement.



Mobile computing revolution


%\chapter{Background and Problem definition}

%\section{Wie klassifiziert man Netzwerktraffic?}
%Basic network characteristics:
%- Bandwidth
%- Bandwidth Jitter
%- Latency
%- Latency Jitter
%- Packet loss
%
%The distributions of these network characteristics can also have a direct impact
%on the application. E.g. for video streaming applications the delay or loss
%of a packet belonging to an I-frame \myglossar{I-Frame}{An I-Frame contains a complete picture of a
%video} can have a large impact on the perceived video qualtiy by the user.
%This is because the frame in question cannot be rendered to the user and
%following p- and b-frames by have used this I-frame as reference so they
%are also in trouble\TODO{REFRENCE, Verlust von I-Frames in streaming
%video,
% ggf.http://166.111.248.20/seminar/2006_4_13/Evaluation%20of%20packet%20loss%20impairment%20on%20streaming%20video.pdf}. 
% -> Matthias fragen, der macht ja sowas.
%}
%Also, the loss of a TCP segment (ACK?) can have different influence
%on the throughput of an application.


%* Show the difference between wireless networks and wired networks

%\begin{tabular}{|l||l|l|}
%\hline
%Network         &  Wired  & Wireless\\
%characteristic  & network & network \\ \hline \hline
%Bandwidth       & High    & Medium--Low \\ \hline
%Bwdth jitter    & Low     & High        \\ \hline
%Latency         & Low     & Low         \\ \hline
%Latency jitter  & Low (1/5) & Low (1/2--1) \\ \hline
%Packet loss     & Low     & Low--High   \\ \hline
%\end{tabular}
% Definition of Jitter: Abrupt and unwanted variations of one or more signal characteristic


%\section{Problems of interactive, real-time applications}
%\section{Problems of wireless networks}
%\section{Problems of mobile ad-hoc networks}
%- Wegfindung in mobilen Ad-hoc Netzen
%  * Es gibt einen Routing Overhead
%  * �bersicht �ber die Protokolle, Klassifizierung
%  * AODV ist ein gutes Protokoll, Warum?, Related work!
% \section{Related work - QoS}
% * Give a short introduction to QoS in wired networks
% * QoS in wireless networks (if any)
% * QoS in MANETs (if any)
%Tabelle mit Vergleich (CEDAR, etc.)

% Hier kommt jetzt wichtiges :-)

\section{Outline}


\section{Terms and Definitions}

Some terms used in computer science and especially in networking are not well-defined or have multiple meanings which all serve different purposes and are valid from one point of view. To avoid any ambiguity, we define terms in this section that will be used throughout this work.

\begin{itemize}
\item[] \hspace{-2em}Bandwidth\\[.4em]
TBD

\item[] \hspace{-2em}Delay\\[.4em]
TBD

\item[] \hspace{-2em}Delay Variation\\[.4em]
% Terminology
% 
% RFC3393 on jitter:
%The variation in packet delay is sometimes called "jitter".  This
%term, however, causes confusion because it is used in different ways
%by different groups of people.
The term 'jitter' is used frequently to describe the variation of latency, however, this term is not well-defined. Hence, we avoid using the term 'jitter' but will use the term 'delay variation' as defined in \cite{rfc3363} which is the average of the absolute differences in delay between two consecutive packets. With $n$ packets and the delay of packet $x$ being $d_x$, the delay variation is defined as follows:
$$ d_{var} = {1\over n-1}\times\sum_{x=1}^{n-1} |d_x - d_{x+1}| $$ 

In addition to delay variation, we will use variance and standard deviation to describe how latency is distributed over time.

\item[] \hspace{-2em}Throughput\\[.4em]
TBD

\end{itemize}

\section{Acknowledgement}







