introduction to computer networks

1. INTRODUCTION TO
COMPUTER NETWORKS
 Presenter: Simwaka P.

2. ‘Lets Discuss’
What is a Computer network?

3. DEFINITION:
network consists of two or more connected
computers or it can be defined as a group of two
or more computer systems linked together.

4. NETWORK
he figure above illustrates the major hardware,
software, and transmission components used in a
simple network: computers,
 network interfaces,
 a connection medium,
 network operating system
 software,
 and either a hub or a switch.

5. IMPORTANCE OF NETWORKS
Networks allow people to share computer hardware,
reducing costs and access more powerful hardware
resources
Networks allow people to share data and software
programs increasing efficiency and productivity
Networks allow people to work together in ways
otherwise would be difficult and impossible for example
video conferencing

6. ‘LETS DISCUSS’
DO YOU KNOW ANY TYPES
OF NETWORKS

7. TYPES OF NETWORKS
here are many different kinds of
networks and ways of classifying them.
ne way of looking at networks is in
terms of their geographic scope

8. TYPES OF NETWORKS
• LAN: it covers a small geographical
area e.g. in the same building, in a
home.
• MAN: it covers a broad geographical
area e.g Buildings, a city
• WAN: it covers a wide geographical
area e.g. the internet

9. WIDE AREA NETWORKS

10. ADVANTAGES OF
NETWORKS
Sharing resources e.g. printers,
Reducing costs
Information and
communication is made easier

11. NETWORK TOPOLOGY
topology is the arrangement
of its modes or devices.

12. NETWORK TOPOLOGIES

13. NETWORK TOPOLOGIES
tar Topologies. Connect end user computers to a central node(e.g
switch). Used for centralizing processing. Since the network is reliant on
the performance of the central node, this topology is less reliable than
either ring or bus. If the central computer fails, the network fails. May be
used in WANs and LANs.
ing Topologies. Connect end user computers together in a ring on a
more equal basis. It is more reliable and has no single point of failure.
Used mostly in LANs.
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14. NETWORK TOPOLOGIES
us Topologies. Connect end user computers on a common channel.
Used commonly in business LANs. It also has no single point of
failure. It is cheaper than ring networks, but sometimes less reliable.
esh Networks. A variation of a ring network that uses a direct
communication line to connect some or all of the computers in the
ring to each other.

15. STAR TOPOLOGY
n a star topology, all devices on the network connect to a
single hub.
igure 8-8 illustrates a simple star network in which all network
components connect to a single hub.
ll network traffic flows through the hub. In an extended star,
multiple layers or hubs are organized into a hierarchy.

16. BUS TOPOLOGY
n a bus topology, one station transmits signals, which travel in both directions along
single transmission segment.
All of the signals are broadcast in both directions to the entire network.
ll machines on the network receive the same signals, and software installed on the
clients enables each client to listen for messages addressed specifically it.
us networks are the most common Ethernet topology.

17. RING TOPOLOGY
ring topology connects network components in a closed loop.
Messages pass from computer to computer in only one
direction around the loop, and only one station at a time may
transmit.
ing networks are used primarily in older LANs using Token
Ring networking software.

18. SOME DEVICES USED IN NETWORKS
witches. A communication processor that makes connections between
telecommunications circuits in a network so a message can reach its intended
destination.
outers. A processor used to interconnect networks with different protocols. Used for
routing messages to their destination.
ubs. It enables temporary connections to be made to different devices, e.g. printers,
servers, workstations etc., on the network. Thus, it allows network resources to be
shared.
ateways. Allow networks with different architectures, e.g. mainframes and
client/servers, to be interconnected.
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19. QUESTIONS?

20. TASK
1) What is a Computer Network?
2) List 2 advantages of computer networks.
3) What is a topology?
4) List three types of computer topologies with the aid of
diagram.
5) Mention 3 devices used in a network.

21. END OF LESSON
Thank You