The usage of Tutorial sessions is
flexible and may vary depending on whether the main
material has been covered in the Lecture session.
The main objective of the CNDS subject
is to use the OSI model to present the functions
of each of the lower five layers in a general way,
and present specific protocols and networks which
are implemented in these layers.
Lecture: The first unit contains
a basic introduction to networking, and focuses
on the OSI model. Students should read the
material on the OSI model as it provides a
good foundation on the rest of the material.
Unit 2 (Network Types), Unit 3 (Ethernet)
and Unit 4 (ATM) focus on Layer 1 and Layer
2; Unit 5 (IP) focuses on Layer 3; Unit 6
(TCP) focus on Layer 4; and Unit 7 (Security)
and Unit 8 (Session/Presentation) mainly focus
on Layer 5 and Layer 6. A key objective of
the module is the complete understanding of
how data travels from one application to another
over the Internet. The OSI model provides
a good foundation for this understanding.
In the teaching pack, the presentation material
contains an introductory chapter on the Internet,
WWW, and so on. This can be used to provide
a broad overview of the subject, and, if possible,
the lecturer should discuss current trends
(such as the move towards new addressing systems).
An important concept in the introductory material
is to show that the WWW is just one of the
applications of the Internet. If possible
outline how the WWW differs from the Internet,
and try to formalize the usage of these terms.
Along with this the difference between an
internet and the Internet can also be presented.
It is unlikely that students will completely
understand the OSI model at this stage, as
it is presented in an abstract way. Once the
main protocols have been covered it should
become more apparent for it usage.
There will be no tutorial session in the
first week, as this could be used to present
the OSI model. If the lecturer has time they
should outline the basic structure of the
module, especially on the aims of the module,
and the timetable (as defined in the Module
In the first week, the students should also
be introduced to the local network, and be
given login's, as well as being shown how
to access the Internet. The first Practical
Worksheet should be completed over a period
of two weeks, and is intended to be a gentle
introduction to the WWW, and its search facilities.
An on-line version is also available from
the cnds@napier WWW site.
The second unit covers some of the fundamentals
of networking, and discusses networking topology,
networking elements, and an introduction to
network cabling. A key concept is the difference
of network topologies, and their advantages
and disadvantages. In addition, it is important
to understand the principles of CSMA/CD, as
this will be expanded in the Ethernet unit.
Finally, the usage of repeaters, bridges and
routers, and their functionality should be
The final exam in the coming years will focus
more on multiple-choice questions, so it is
important that students gain access in these.
If possible, the lecturer should get students
to complete the tutorial for Unit 1 in a tutorial
session. The answers to these could be discussed
in an interactive way. This tutorial can also
be completed as an on-line exam at the cnds@napier
This should involve the completion of the
research. Hopefully network logins, the distribution
of notes, and so on, should be sorted-out,
and every student can get access to the network,
and the Internet.
LAYER AND IP
As the project and some of the practical
work is based on TCP/IP communications, it
is important to cover the network layer before
the rest of the material. This unit presents
the network layer in a general way, in respect
to its two main functions: network addressing
and path determination. It then discusses
the most widely used network layer protocol,
which is IP. The main points to emphasize
are data encapsulation, the IP header, IP
classes and IP allocation. If possible use
examples of IP address allocation from your
own institution, and how these are used to
segment the network. Note that there is no
need to go into detail in many of the areas,
as these should be left to the student to
read the material in their own time.
The tutorial session can either be used to
cover the rest of the material from the IP
unit, or can be used to cover the tutorial
test. If there is not enough time for the
tutorial, the tutorial in the following week
can be used to cover two of the tutorial sessions.
This worksheet gives a basic introduction
to the concept of ping, which is one of the
most widely used techniques for testing a
network connection. Various WWW sites around
the Internet have been chosen. These can be
changed, depending on the situation. NOTE:
This worksheet can be customized for the required
setup, the main principle is to show how ping
is used to sense if a host is operating, and
to give a basic measure of the time that data
packets take to reach a destination.
LAYER AND TCP
Unit 6 provides a foundation on TCP/UDP. As
with the unit on IP, this unit presents the
functionality of the corresponding layer:
the transport layer. This is then expanded
to show how TCP/UDP implements the functions
of the transport layer. The main point to
emphasize is the functions of the Transport
Layer, such as flow control and windowing,
and how these are implemented in the TCP protocol.
Particular attention should be paid to the
difference between TCP and UDP, and that UDP
would be used where a higher level protocol
provides error detection, and recovery. As
with the previous lectures, the students should
be encouraged to read the whole of the unit.
There is no need for the lecturer to go into
any great detail on the topic as this is part
of the independent learning for the student.
As much as possible students should be encouraged
to ask questions to the lecturer or from the
This class can either be used to cover the
tutorial sheets on Unit 2 and Unit 5, or can
be used to cover some of the material not
covered in lecture.
This worksheet outlines some of the main
concepts in determining the route to a remote
note (using traceroute). As with ping, this
is used extensively to test a network when
there is a fault. NOTE: This worksheet can
be customized for the required setup.
Security is becoming one of the major issues
on the Internet, and within corporate networks,
thus this is an important area to discuss
the main methods of protecting a network from
external sources. The usage of firewalls is
key to the understanding network security,
especially in terms of how the firewall filters
at both the network and the transport layer.
If possible try and relate up-to-date security
breaches to the material, especially in relation
to the spread of macro/worm viruses. Along
with this the material covers some of the
ways that users must guard against external
parties from reading and/or modifying their
data. An important concept is that Ethernet,
IP and TCP are open technologies and provide
very little protection against users viewing
and editing any transmitted or received data.
This class can either be used to catch up
on previous material, or to cover previous
This worksheet gives a basic introduction
to how a user can determine the basic setup
of their host (using WINIPCFG or IPCONFIG).
NOTE: This worksheet can be customized for
the required setup.
The third unit covers Ethernet, and should
provide a foundation in the methods that Ethernet
uses to communicate, and the different types
of Ethernet. In the tutorial, the students
will be given the second multiple-choice tutorial,
which is based on the material in Unit 2.
The forth unit gives an introduction to ATM. The main points to emphasize
are that ATM integrates different types of
networking traffic, and the method that ATM
uses to route cells around the network. If
possible discuss a practical network which
uses ATM (see EaStMAN and SuperJANET structure,
for an example). A few of the MANs around
the UK are:
main emphasis on this unit is on the difference
between client-side includes and server-side
includes. If possible highlight how client-side
includes and server-side includes are integrated
into a WWW page.
Note 1. Practicals require customization for the
local network, and will change depending on each
College/University. Drafts of the Practicals and
the Project are enclosed, and final versions will
depend on the local College/University.