unit 1

1. COMPUTER NETWORK
INTRODUCTION

2. COMPUTER NETWORK
Network
A network is any interconnection of two or more station that
wish to communicate.
Computer Network
A computer network is interconnection of two or more
nodes(computer) for sharing information and communication.

3. NETWORK BENEFITS
 The network provided to the users can be divided into
two categories:
i. Sharing
ii. Connectivity

4. DISDAVATAGES OF NETWORKS
 High cost of installation
 Requires time for administration
 Failure of server
 Cable faults

5. Application Computer Network
 Sharing of resources such as printer.
 Sharing of expansive software and database.
 Communication from one computer to another.
 Exchange of data and information among users.
 For educational purpose.
 Sharing information over the geographically wide
area.

6. OTHER BENEFITS OF
COMPUTER NETWORK
 Increased speed
 Reduced cost
 Improved security
 Centralized software managements
 Electronic mail
 Flexible access

7. COMPONENTS OF COMPUTER
NETWORK
 Two or more computers
 Cables as links between the computers
 A network interfacing card(NIC) on each computer
 Switches
 Software called operating system(OS)

8. SHARING RESOURCES
 Types of resources are:
1. Hardware: A network allows users to share many
hardware devices such as printers , modems, fax
machines, CD ROM, players, etc.
2. Software: sharing software resources reduces the cost
of software installation, saves space on hard disk.

9. Uses Of Computer Network
 Business Application
 Home Application
 Mobile Users
 Social Issue

10. Business Application
 Many companies have a substantial number of computers.
For example, a company may have separate computers to
monitor production, keep track of inventories, and do the
payroll.
 Initially, each of these computers may have worked in
isolation from the others, but at some point, management
may have decided to connect them to be able to extract and
correlate information about the entire company.
 Put in slightly more general form, the issue here is resource
sharing.
 The data are stored on powerful computers called servers

11. Home Application
 There is no reason for any individual to have a computer in
his home.
 People initially bought computer for word processing and
games.
 Recently the biggest reason to buy home computer for
Internet access.
 home network are used in entertainment including,
listening to music, photos and videos.

12. Mobile Users
 Mobile computers, such as notebook computers and
personal digital assistants (PDAs), are one of the fastest
growing segments of the computer industry.
 People on the go often want to use their mobile device to
read and send mails, tweet watch movies, download music,
play games or suit for the web application.

13. Social Issue
 Social network messages boards, content sharing sites and a
host of other application allow people to share their views
with different minded individuals.
 As long as a subjects restricted to terminal topic or business
like gardening not two many problems will arise.

14. Types Of Computer Network
 Local area network(LAN)
 Metropolitan area network(MAN)
 Wide area network(WAN)
 Personal area network(PAN)
 Campus area network(CAN)

15. Local area network(LAN)

16. Local area network(LAN)
 LAN is a Local Area Network which spans a small
geographical area. They are limited to a single building bor
campus i.e. around 1km.
 the users in LAN can share expensive resources and
communicate with each other by spending message.
 The various characteristics are as follows:
1) Size : limited number of companies i.e. approximately 50
computers.
2) Transmission media: it would be either coaxial, twisted
pair or fiber optic cable which is depending b on the cost of
the LAN network.
3) Data rate:10 Mbps
4) Topology: bus or star toplogy.

17. Local area network(LAN)

18. Metropolitan area network(MAN)

19. Metropolitan area network(MAN)
 A metropolitan area network, or MAN, covers a city. The
best-known example of a MAN is the cable television
network available in many cities. This system grew from
earlier community antenna systems used in areas with poor
over-the-air television reception.
 Characteristics are:
1) Size: it is limited upto one city.
2) Speed: it is between 10-100Mbps
3) It can be both data and voice
4) Application: LAN to LAN connection within city.

20. Wide area network(WAN)

21. Wide area network(WAN)
 A wide area network, or WAN, spans a large geographical
area, often a country or continent
 It uses similar technology as LAN. It can be a single network
such as cable TV network, or a measure of connecting a
number of LAN’s o a large network so that resources can be
shared LAN to LAN as well as device to device.
 Characteristics are:
1) Size: unlimited number of computers can be added
2) Speed: more than 100Mbps
3) Topology: hybrid topology
4) Application: internet

22. Personal area network(PAN)

23. Personal area network(PAN)
 A personal area network is a computer network
organized around an individual person.
 It generally consists of a mobile computer, a cell
phone or personal digital assistant. PAN enables the
communication among these devices.
 It can also be used for communication among
personal devices themselves for connecting to a digital
level network and internet.
 The PANs can be constructed using wireless or
cables.

24. Campus area network(CAN)

25. Campus area network(CAN)
 The campus area network is made up of an
interconnection of LAN with limited geographical
area.
 Network equipment's such as switches, routers and the
transmission media i.e. optical fiber etc. are almost
entirely owned by the campus owner.

26. DISTINGUISH BETWEEN
LAN,WAN,MAN

27. NETWORK CLASSIFICATION BY
THEIR COMPONENT ROLE
 PEER TO PEER NETWORK
 CLIENT SERVER NETWORK

28. PEER TO PEER NETWORK
 In peer to peer network each computer is responsible for making
its own resources available to other computers on the network.
 Each computer is responsible for setting up and maintaining its
own security for these resources.
 Also each computer is responsible for accessing the required
network resources from peer to peer relationships.
 Peer to peer network is useful for a small network containing
less than 10 computers on a single LAN .
 peer to peer network each computer can function as both client
and server.
 Peer to peer networks do not have a central control system.
There are no servers in peer networks.
 Peer networks are amplified into home group

29. ADVANTAGES OF PEER TO
PEER NETWORK
 Use less expensive computer hardware
 Easy to administer
 No NOS required
 More built in redundancy
 Easy setup & low cost

30. DISADVANTAGES OF PEER TO
PEER NETWORK
 Not very secure
 No central point of storage or file archiving
 Additional load on computer because of resource
sharing
 Hard to maintain version control

31. CLIENT/SERVER NETWORK
 In client-server network relationships, certain computers act as
server and other act as clients. A server is simply a computer, that
available the network resources and provides service to other
computers when they request it. A client is the computer running
a program that requests the service from a server.
 Local area network(LAN) is based on client server network
relationship.
 A client-server network is one n which all available network
resources such as files, directories, applications and shared
devices, are centrally managed and hosted and then are accessed
by client.
 Client serve network are defined by the presence of servers on a
network that provide security and administration of the network.

32. ADVANTAGES OF
CLIENTSERVER NETWORK
 Very secure
 Better performance
 Centralized backup
 very reliable

33. DISADVANTAGES OF
CLIENTSERVER NETWORK
 requires professional administration
 More hardware intensive
 More software intensive
 Expensive dedicated software

34. Distinguish between peer to
peer and client server

35. TYPES OF SERVERS
 File server : storing, retrieving and moving the data. A user can
read, write, exchange and manage the files with the help of file servers.
 Printer server: The printer server is used for controlling and
managing printing on the network. It also offers the fax service to the
network users.
 Application server: The expensive software and additional
computing power can be shared by the computers in a network with he
help of application servers.
 Message server: It is used to co-ordinate the interaction between
users, documents and applications. The data can be used in the for of
audio, video, binary, text or graphics.
 Database server: It is a type of application server. It allows the
uses to access the centralized strong database

36. Internetworking
 Internetworking started as a way to connect
disparate types of computer networking technology.
Computer network term is used to describe two or
more computers that are linked to each other. When
two or more computer LANs or WANs or computer
network segments are connected using devices such
as a router and configure by logical addressing
scheme with a protocol such as IP, then it is called
as computer internetworking.
 There are chiefly 3 unit of Internetworking:
1 Extranet
2 Intranet
3 Internet

37. Wireless network
 Wireless network is a network set up by using radio
signal frequency to communicate among computers
and other network devices. Sometimes it’s also
referred to as WiFi network or WLAN. This network is
getting popular nowadays due to easy to setup
feature and no cabling involved. You can connect
computers anywhere in your home without the need
for wires
 The two main components are wireless router or
access point and wireless clients.

38. Wireless network