\chapter{Introduction}

Networks and distributed processing systems have become critical
factors in the business world. Companies and organizations develop
large and complex networks with an increasing number of applications
and users. The need for high capacity IP networks is growing because
of the new WWW- and multimedia applications, faster data transmission
in mobile networks, and IP telephony. Today's routed IP networks
suffer from serious problems related to scalability, manage-ability,
reliability and cost.

Helsinki University of Technology has started IPMAN-project in
1999. The target of the IPMAN-project is to research and develop a
network management paradigm for massive IP-networks.

\section{Changes in network management}

Introduction of new equipment and new technologies means introduction
of new information systems, which also increases the number of data
repositories and fault management systems. As networks become larger
and more complex, tools and applications to ease network management
are critical. Automated network management is needed~\cite{b24}.

Time is a critical factor in network management (see
figure~\ref{fig:networkmanagement}). Managers strive for shorter
cycles and customers demand faster response. Shorter cycles lead into
lower costs and greater productivity~\cite{b16}. Effective use of
network facilities can improve a competitive position, create new
market opportunities and afford efficient communications between
business units and customers.

\begin{figure}[htb]
\begin{center}
\epsfxsize.7\textwidth
\epsfbox{kuvat/network_management}
\caption{Network management, modified~\cite{b16}}
\label{fig:networkmanagement}
\end{center}
\end{figure}

Network management views the computing environment as a collection of
co-operating systems connected by various communication
mechanisms. Sun Microsystems expresses that the network is the
computer. This means that effective system management is thinking the
network as a single, multilayer entity, one that requires its own
care~\cite{b18}. An important aspect is that management is useless to
a company if it does not solve business problems and ease the work of
operators~\cite{b27}.

A recent Gartner Group study "Strategies to Control Distributed
Computing's Exploding Costs" reports that while the strategic value of
systems and networks continues to increase, the escalating cost of
managing that technology is undermining the organization's expected
return on its investment~\cite{b16}.

Effective and to business strategy adaptive network management requires: 
\begin{itemize}
\item The right abstraction level of information,
\item Information at the right time, and
\item Information in an easy-to-use format~\cite{b16}.
\end{itemize}

There are three types of network management systems: discrete,
centralized and hierarchical management systems. To business strategy
adaptive network management contains functions such as technology
selection, network automation, capacity planning, predictive problem
avoidance and sophisticated trouble-shooting. These functions all
require information that goes beyond the data available to most of
network managers, who determine the benefits and the risks of
networks.

\section{Future trends}

Experts forecast the changes that will happen in the next
years. According to James Herman in the Sixth IFIP/IEEE International
Symposium on Integrated Network Management (May 1999): "The main
affect of the Internet is to enable the rise of virtual business and
services. There will also be large data volumes (more customers
$\times$ more interactions with customers $\times$ more data per
interaction = an explosion). PC will no longer be the dominant access
device, the network is the center of everything. There will be more
need for mobile and wireless infrastructure. Data will find you
wherever you are. When there are no connectors, it means lighter,
cheaper and simple devices."

Figure~\ref{fig:internet} expresses the vision of Internet
development. Almost every telephone company has become involved in
delivering non-telephone services to end users. Plain Old Telephone
Service (POTS) is the basic telephone call service. Internet Access
Provider's (IAP's) role is to ensure that the end user has a reliable
connection to the Internet.

Most cable television (CATV) providers are interested in offering
telephone and Internet services as well as video-on-demand
services. The Hybrid Fiber-Coax (HFC) network is an emerging cable
architecture for providing residential video, voice telephony, data,
and other interactive services to end users over fiber optic and
coaxial cables. The HFC network can provide the bandwidth that some
multimedia applications require, using the spectrum from 5 MHz to 450
MHz for conventional downstream analog information, and the spectrum
from 450 MHz to 750 MHz for digital broadcast services such as voice
and video telephony, video-on-demand, and interactive television.

An alternative to a coaxial or fiber/coaxial network is offered by a
technology that can transmit relatively high-speed data over untwisted
or twisted pair cables for distances up to 4000 m. The technology can
use existing digital telephone subscriber lines. The High bit-rate
Digital Subscriber Line (HDSL) offers bi-directional transmission at
1.5 Mbps with a transmission bandwidth of 200 kHz. Asymmetric Digital
Subscriber Line (ADSL) can transmit four one-way 1.5-Mbps video
signals, in addition to a full-duplex 384-Kbps data signal, a 16-Kbps
control signal, and analog telephone service. ADSL has a transmission
bandwidth of 1.1 MHz.

Many end users want to access services not only in their homes, but
also outside the homes. Wireless transmission enables the desired
mobility among users. Because the bandwidth is shared, users are
grouped into small cells. The users in each cell communicate with a
single base station, and base stations are linked together by a wired
network.

Satellite transmission also facilitates mobility. Because the
transmission area covered by a satellite is very large, it is well
suited for video and audio broadcasting~\cite[pages 16--20]{b3}.

\begin{figure}[htb]
\begin{center}
\epsfxsize.6\textwidth
\epsfbox{kuvat/internet}
\caption{The internet picture~\cite{b6}}
\label{fig:internet}
\end{center}
\end{figure}

\section{Structure of this document}

Chapter~\ref{ch:nmm} studies models developed to classify and order
network management problems. Chapter~\ref{ch:nmp} describes some
protocols used for network management, and chapter~\ref{ch:future}
covers some possible future trends in network management.

Professor Olli Martikainen suggested use of a reference model, where
network management is divided into four levels (see
figure~\ref{fig:refmodel}).

\begin{figure}[htb]
\begin{center}
\epsfxsize.35\textwidth
\epsfbox{kuvat/ref_model}
\caption{Reference model by Professor Olli Martikainen}
\label{fig:refmodel}
\end{center}
\end{figure}

Chapters~\ref{ch:contents} to~\ref{ch:physical} study each layer of
the reference model. Finally, chapter~\ref{ch:commercial} gives a
short summary of commercial network management tools.



