A computer network connects multiple computers together to allow for sharing of resources and communication between devices. The main components of a computer network include network interface cards (NICs), hubs, switches, cables, routers, and modems. There are several types of computer networks including personal area networks (PANs), local area networks (LANs), wide area networks (WANs), wireless local area networks (WLANs), and metropolitan area networks (MANs). Network analysis involves capturing and inspecting network traffic to determine what is happening on the network and ensure security.

1. INTRODUCTION
What is a Computer Network?
o Computer Network is a group of computers connected with each other
through wires, optical fibres or optical links so that various devices can interact
with each other through a network.
o The aim of the computer network is the sharing of resources among various
devices.
o In the case of computer network technology, there are several types of networks
that vary from simple to complex level.
Components Of Computer Network:
NIC (National interface card)
NIC is a device that helps the computer to communicate with another device. The
network interface card contains the hardware addresses, the data-link layer protocol

2. use this address to identify the system on the network so that it transfers the data to
the correct destination.
There are two types of NIC: wireless NIC and wired NIC.
o Wireless NIC: All the modern laptops use the wireless NIC. In Wireless NIC, a
connection is made using the antenna that employs the radio wave
technology.
o Wired NIC: Cables use the wired NIC to transfer the data over the medium.
Hub
Hub is a central device that splits the network connection into multiple devices. When
computer requests for information from a computer, it sends the request to the Hub.
Hub distributes this request to all the interconnected computers.
Switches
Switch is a networking device that groups all the devices over the network to
transfer the data to another device. A switch is better than Hub as it does not
broadcast the message over the network, i.e., it sends the message to the device
for which it belongs to. Therefore, we can say that switch sends the message
directly from source to the destination.
Cables and connectors
Cable is a transmission media that transmits the communication signals. There are
three types of cables:
o Twisted pair cable: It is a high-speed cable that transmits the data
over 1Gbps or more.
o Coaxial cable: Coaxial cable resembles like a TV installation cable. Coaxial cable
is more expensive than twisted pair cable, but it provides the high data
transmission speed.
o Fibre optic cable: Fibre optic cable is a high-speed cable that transmits the
data using light beams. It provides high data transmission speed as compared
to other cables. It is more expensive as compared to other cables, so it is
installed at the government level.
Router: Router is a device that connects the LAN to the internet. The router is mainly
used to connect the distinct networks or connect the internet to multiple computers.

3. Modem: Modem connects the computer to the internet over the existing telephone
line. A modem is not integrated with the computer motherboard. A modem is a
separate part on the PC slot found on the motherboard.
system without the user’s knowledge. Hence the distributed system is a
special case of network system, one whose operating system has a high
degree of transparency
Objectivesof ComputerNetworks
ObjectivesofComputerNetwork
Right from the day of computer automation, a computer
has developed computer in each department. For
example, the task can be to keep of track off
inventories, monitor productivity and maintain
accounts. Initially, this computer in different department works as an
isolation from other computer. These provided the necessary computer
assistance in the activities pertaining to the respective department. It was
not possible to share information among the departments. As a result, the
information was replicated wherever needed. This increased redundancy
caused increased in storage space, less data consistency etc.
1. Resource sharing is the main objective of the computer network. The
goal is to provide all the program, date and hardware is available to
everyone on the network without regard to the physical location of the
resource and the users.
2. The second objective is to provide the high Reliability. It is achieved by
replicating the files on two or more machines, so in case of unavailability
(due to fail of hardware) the other copies can be used.
3. Computer organization has helped organization in saving money. This is
due to the fact that the small computer has much better price to the
performance ratio comparison than the large computer like mainframe.
4. Computer network have provided means to increase system
performance as the work load increases (load balancing). In the days of
mainframe when the system was full it was to replace with the other large
mainframe computer, usually at and expensive rate not convenience for
user.

4. Types of Computer Networks
A computer network is a cluster of computers over a shared communication
path that work for the purpose of sharing resources from one computer to
another, provided by or located on the network nodes.
Some of the uses of computer networks are the following:
 Communicating using email, video, instant messaging, etc.
 Sharing devices such as printers, scanners, etc.
 Sharing files
 Sharing software and operating programs on remote systems
 Allowing network users to easily access and maintain information
Types of Computer Networks
1. Personal Area Network (PAN)
2. Local Area Network (LAN)
3. Wide Area Network (WAN)
4. Wireless Local Area Network (WLAN)
5. Campus Area Network (CAN)
6. Metropolitan Area Network (MAN)
7. Storage Area Network (SAN)
8. System-Area Network (SAN)
9. Passive Optical Local Area Network (POLAN)
10. Enterprise Private Network (EPN)
11. Virtual Private Network
These are explained as following below.
1. Personal Area Network (PAN) :
PAN is the most basic type of computer
network. This network is restrained to a single
person, that is, communication between the
computer devices is centred only to an
individual’s work space. PAN offers a network
range of 10 meters from a person to the device providing communication.
Examples of PAN are USB, computer, phone, tablet, printer, PDA, etc.

5. 2. Local Area Network (LAN) :
LAN is the most frequently used
network. A LAN is a computer network
that connects computers together
through a common communication
path, contained within a limited area,
that is, locally. A LAN encompasses
two or more computers connected
over a server. The two important
technologies involved in this network are Ethernet and Wi-fi.
Examples of LAN are networking in a home, school, library, laboratory,
college, office, etc.
3. Wide Area Network (WAN) :
WAN is a type of computer network that
connects computers over a large geographical
distance through a shared communication
path. It is not restrained to a single location
but extends over many locations. WAN can
also be defined as a group of local area
networks that communicate with each other.
The most common example of WAN is the
Internet.
4. Wireless Local Area Network (WLAN) :
WLAN is a type of computer network that acts
as a local area network but makes use of
wireless network technology like Wi-Fi. This
network doesn’t allow devices communicating
over physical cables like in LAN, but allows
devices to communicate wirelessly.
The most common example of WLAN is Wi-Fi.
5. Campus Area Network (CAN) :
CAN is bigger than a LAN but smaller than a
MAN. This is a type of computer network
which is usually used in places like a school
or college. This network covers a limited
geographical area that is, it spreads across
several buildings within the campus.
Examples of CAN are networks that cover
schools, colleges, buildings, etc.

6. 6. Metropolitan
Area Network
(MAN) :
A MAN is larger
than a LAN but
smaller than a
WAN. This is the
type of computer
network that
connects
computers over a
geographical
distance through a shared communication path over a city, town or
metropolitan area.
Examples of MAN are networking in towns, cities, a single large city, large
area within multiple buildings, etc
Computer Network Analysis
Network analysis (also known as traffic analysis, protocolanalysis, sniffing,
packet analysis, eavesdropping, and so on) is the process of capturing network
traffic and inspecting it closely to determine what is happening on the
network. A network analyzer decodes the data packets of common protocols
and displays the network traffic in readable format. A sniffer is a program that
monitors data traveling over a network. Unauthorized sniffers aredangerous
to network security because they are difficult to detect and can be inserted
almost anywhere, which makes them a favorite weapon of hackers. A network
analyzer can be a standalone hardwaredevicewith specialized software, or
softwarethat is installed on a desktop or laptop computer. The differences
between network analyzers depend on features such as the number of
supported protocols it can decode, the user interface, and its graphing and
statistical capabilities. Other differences include inference capabilities (e.g.,
expert analysis features) and the quality of packet decodes. Although several
network analyzers decodethe sameprotocols, somewill work better than
others for your environment.
Conclusion
A network is two or more computers connected together using a
telecommunication system for the purpose of communicating and sharing
resources. Without having a network, Companies would not be able to share
resources and increase productivity more effectively.