A computer network is a set of connected computers. Computers on a network are called nodes. The connection between computers can be done via cabling, most commonly the Ethernet cable, or wireless through radio waves. Connected computers can share resources, like access to the Internet, printers, file servers, and others. A network is a multipurpose connection, which allows a single computer to do more. ↓↓↓↓ Read More: @ Kindly Follow my Instagram Page to discuss about your mental health problems- -----> https://instagram.com/mentality_streak?utm_medium=copy_link @ Appreciate my work: -----> behance.net/burhanahmed1 Thank-you !

1. COMPUTER
NETWORK

2. Computer Network
A computer network is a system in which, a
large number of computers are
interconnected together to communicate with
each other via a communication medium.
OR
Two or more computers connected together
through a communication medium to share
resources is called computer network.

3. Data and information can be shared among
different users of a network.
Resources like printer, CD drive, Hard disk
and software can be share.
By sharing resources we can save large
amount of money.
Expensive and costly software can also be
shared via networking.
Advantages of Computer Network

4. Advantages of Computer Network
Internet is also example of a network. We
can contact any body in the world.
We can send messages to different users of
the network speedily without any cost.

5. There are two types of computers used in
computer network.
Terminal/Node
The computers, which take part in the activities
of the network, are called terminal or node.
Server
It is a central computer in a network, which
controls all the terminals of the network. It is
used to fulfill all the requests from terminals.
Types of computers used in a
Network

6. LAN (Local Area Network)
“A network of computers connected through
some guided media and covers limited area is
called Local Area Network”.
OR
“LAN is the network of computers that are
connected together through Ethernet cards”.
Types of Computer Network

7. Example:
A network within an office building, a network
within a university campus to connect
computers of different departments.
Device used to connect computers in LAN
The computers are usually connected through
cables. A network card (Ethernet Card) is used
in computer to make connection through
cables. The distance among computers
depends upon the data transmission capability
of transmission media.
Local Area Network

8. Uses and Advantages of LAN
Each computer in the network can use the
resources of other computers.
The information moves directly from computer to
computer. This saves time and increases
efficiency.
Computer can share resources and devices such
as Fax Modems, printers. Thus one office may
have only one high quality laser printer and all
computers can use it.
The data transmission speed in a LAN is very
high. It varies from 10 to 100 million bits per
second (Mbps).
In addition to data transmission, human voice
Local Area Network

9. Video conferencing is possible over LAN.
We can share centralized database in LAN.
It is used to share expensive software like
ORACLE.
Local Area Network

10. WAN (Wide Area Network)
“ A wide area network is a network of
geographically distant computers and terminals.”
Wide area networks cover long distances. They
connect computers in different cities, countries and
continents.
Types of Computer Network

11. Example:
Internet is the largest WAN that connects
millions of computers worldwide. It is
connecting more than 20,000 LAN’s and
millions of PCs world over.
Medium used to connect computers in WAN
If we want to use telephone lines as medium
then normally modem card is used in
computer. There are also other medias like
microwave or satellite used for connection
between computers of a WAN.
Wide Area Network

12. Uses and Advantages of WAN
With the invention of modem card, it is
possible to share data among computers that
are located at far more distances from each
other even form one continent to another.
WAN also supports features like Email and
File transferring from one place to any where
in the world using WWW facility.
Workgroup computing is an important facility
provided by WANs.
WAN uses VSAT, Satellite or Microwave
Wide Area Network

13. Communication system to transmit data from one
place to another.
Special telephone lines can be hired, which can
carry data at rates of 64000, 128000, 512000,
2048000 bauds.
Wide Area Network

14. MAN (Metropolitan Area Networks)
“MAN is also like WAN and LAN because this
is a communication network, but they cover
the middle ground between LANs and WANs”.
A MAN covers greater distances at higher
data rates than a LAN.
A MAN is a relatively new class of network, it
serves a role similar to an ISP, but for
corporate users with large LANs.
Types of Computer Network

15. Example:
An ISP, Cable TV operator, Mobile Phone Networks
etc.
There are three important features, which discriminate
MANs from LANs or WANs:
Coverage:
The network size falls intermediate between LANs and
WANs. A MAN typically covers an area between 5 and
50 km diameter. Many MANs cover an area the size of
a small city, some times we can found MANs may be
as small as a group of nearby corporate offices or as
large as the city of Lahore.
Ownership:
A MAN might be owned and operated by a single
organization, but it is usually used by many individuals
and organizations other than the owner.
Metropolitan Area Network

16. Example:
Cable TV operators have their own networks
normally covers the whole city or some specific
area of that city but the users are the public.
MANs might also be owned and operated as
public utilities.
Example:
Telephone connections, ATMs
Connectivity
A MAN usually interconnects a number of local
area networks (LANs) using a high-capacity
backbone technology, such as fiber-optical links,
and provides up-link services to wide area
networks like Internet.
Metropolitan Area Network

17. Collection of Networks

18. NETWORK
TOPOLOGY

19. Network Topology
The arrangement of computers in a network
is called network topology.
OR
The physical layout of a network is called
network topology.
OR
The scheme of connecting a number of
computers in the form of a network is
called network topology.

20. Network Topology
There are following network topologies used
to form a network.
Bus Topology
Star Topology
Ring Topology

21. Bus Topology
In Bus topology, all computer or nodes are
connected to a common communication
medium.
 A special type of central wire is used as the
communication medium. This central wire is
called bus or backbone. All the computers are
attached to the bus. The ends of the bus are
closed with terminators.
Terminator
A terminator is a special device used to
absorb signals.

22. Bus Topology
Terminator

23. Bus Topology
Advantages
It is simple and reliable for very small
networks.
It is easy to use and understand.
Its cost is very low as compared to other
topologies.
It can easily be extended to include more
computers in network.

24. Bus Topology
Disadvantages
If one workstation goes faulty, all
workstations are affected.
It can be used only for a few computers. As
the number of computers increases, the
network gets slower.
It is difficult to troubleshoot a bus.
If the bus cable is damage, whole network
goes down.

25. Ring Topology
In ring topology, each computer is connected
to two adjacent nodes. Each computer or
node is connected to the next computer and
the last computer is connected to the first.
Thus a ring topology formed.

26. Ring Topology

27. Ring Topology
Advantages
Signals do not weaken as every computer
strengthens and retransmits the signal.
All computers on the ring have equal
access to the network.
Ring networks are moderately easy to
install.

28. Ring Topology
Disadvantages
A single break in the cable can disrupt the
entire network.
It is difficult to manage the ring network
because it is difficult to add or remove a
single computer.
It is expensive than Bus topology.

29. Star Topology
In star topology, all the computers or nodes
are directly connected to a central device.
The devices that normally used as central
device are called hub and switch.

30. Star Topology

31. Star Topology
Advantages
It is easy to modify a star network. New
computers can be added to the central device
or any computer can be removed without
affecting the network.
It is usually easy to troubleshoot a star
network.
Resource sharing is possible among
computers. E.g. hard disk, CD etc.
If any computer in the star network fails,
rest of the network is not affected.

32. Star Topology
Disadvantages
If the central device fails, the whole network
breaks down.
Star network requires more communication
cable than any other network
It is very costly.