A network consists of two or more computers that are linked in order to share resources (such as printers and CDs), exchange files, or allow electronic communications. The computers on a network may be linked through cables, telephone lines, radio waves, satellites, or infrared light beams.

A Computer Network is a set of two or more interconnected computers and a set of hardware devices.

A computer network , often simply referred to as a network , is a collection of computers and devices connected by communications channels that facilitates communications among users and allows users to share resources with other users.

What are the uses/ application/ goals of Networking?
The uses of Networking are:
•  Resource Sharing
•  Reliability
•  Access To Remote Database
•  Reduced Costs
•  Fast Communication Facilities.
•  Increased Communication Facilities.

Why is the Internet considered a network?

The Internet is the world's largest network because it's a collection of computers and servers that are connected to each other globally using routers and switches . The Internet works the same way a network would in a home or office but has millions of more computers, routers, and switches.


There are basically four types of networks:-
•  LAN - Local Area Network
•  MAN - Metropolitan Area Network
•  WAN - Wide Area Network
•  PAN - Personal Area Network

LAN - Local Area Network- LAN connects networking devices with in short spam of area, i.e. small offices, home, internet cafes etc. LAN uses TCP/IP network protocol for communication between computers. It is controlled and administered by single person or organization.

WAN - Wide Area Network- WAN, wide area network cover large distance for communication between computers. The wide area networks are the network that spread over countries. The Internet itself is the biggest example of Wide area network, WAN, which is covering the entire earth. WAN is distributed collection of geographically LANs. A network connecting device router connects LANs to WANs.

MAN - Metropolitan Area Network- Metropolitan Area Network s are the networks that spread over a city. For example TV networks that are spread over a city. Metropolitan area network falls in middle of LAN and WAN, It covers large span of physical area than LAN but smaller than WAN, such as a city.

PAN - Personal Area Network- Personal Area Network refers to a small network of communication- capable devices within a range of reach ability of an individual person. The range is typically upto 10 meters.


The pattern of interconnection of nodes in a network is called the Topology. Topology can be considered as a virtual shape or structure of a network.
Different Computer network topologies are: -
Star Topology, Bus Topology (Liner Topology), Tree Topology, Ring Topology (Circular Topology), Graph Topology, Tree Topology , Mesh Topology

Mesh Topology

In a true mesh topology every node has a connection to every other node in the network.

Star Topology

All devices are connected to a central hub / switch. Nodes communicate across the network by passing data through the hub or switch.

Bus Topology

All devices are connected to a central cable, called the bus or backbone .

Ring Topology

All devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices, one on either side of it.

Tree Topology

It is a hybrid topology. In Tree topology Groups of star-configured networks are connected to a linear bus backbone.

Tree topologies are comprised of the multiple star topologies on a bus. Tree topologies integrate multiple star topologies together onto a bus. Only the hub devices can connect directly with the tree bus and each Hub functions as a root of a tree of the network devices.

Graph Topology

In this topology, nodes are connected together in an arbitrary fashion. A link may or may not connect two or more nodes.


•  What is Nodes (Workstations)?
Ans: - Workstations refers to the computers that are attached to a network. Each computer or device on the network is a node.
•  What is a Server? Explain the different types of Servers?
Ans: - Server is a computer that facilitates the sharing of data, software and hardware resources on the network.
Servers can be of two types: (i) non-dedicated server and (ii) dedicated server
Non-dedicated Servers: A non-dedicated server is a computer system that can act both as a workstation and a server.
Dedicated servers: A dedicated server is a Computer system that is reserved for server's job and its only job is to help workstations to access data, software and hardware resources.
•  What does NIU? What is its use? What is the other name of NIU?
Ans: - NIU stands for Network Interface Unit.
A Network Interface Unit is an interpreter that helps activate communication between the server and workstations.
NIU is also called TAP (Terminal Access Point) and NIC (Network Interface Card)
•  What is MAC Address?
Ans: - The MAC (Media Access Control) Address refers to the physical address given to the (NIC) Network Interface Card by Network Interface Card manufacturer.
MAC Address is a 6-byte address with each byte separated by a colon e.g.,
10 : R5 : 04 : 44 : 2A : VI
•  What is Protocols? Name some commonly used protocols?
Ans: - While communicating on a Network a computer has to follow a set of rules, these rules are called Protocols.
Some protocols are:-
TCP/IP:- Transmission Control Protocol/ Internet Protocol.
HTTP:- Hyper Text Transfer Protocol.
FTP:- File Transfer Protocol.
•  What is IP Address?
Ans:- IP(Internet Protocol) Address is a Unique address assigned to a computer system while it is on a TCP/IP Network.
(There must be four numbers separated by dots. Numbers should between 0 - 255 )
•  What is domain name? What are the different parts of a Domain name?
Ans:- Domain Name is a unique name assigned to a website. Domain name are easier to remember than IP Address.
A Domain name generally contains three parts:
- www
- name describing the website purpose
- top level domain (such as .com, .net, .org, .edu, .in, etc)
•  What is Domain Name Resolution (DNS)?
Ans:- The process of obtaining corresponding IP address from a Domain Name is called Domain Name Resolution.
•  What is Point to Point Link?
Ans:- A P-P (Point-to-Point) link relies upon two functions –transmit and receive. The main characteristic of Point to Point network is that each station receives exactly one transmitter, and each transmitter transmits to exactly one receiver.
•  Name and explain different Network Devices.
Ans: Modem- A Modem (MOdulator- DEModulator) is a device that connect Telephone line to computer. It converts Digital signal into analog and vice-versa. It is used to connect a PC with telephone lines to access internet or make voice call and FAX using PC.
Hub- A Hub is a hardware device that is used to connect several computers together. Hubs can be either active hubs or passive hubs.
Switch- A Switch is a device that is used to segment networks into different subnetworks called subnets or LAN segments.
Repeater- A Repeater is a device that amplifies a signal being transmitted on the network.
Bridge- A Bridge is a device that links two similar networks together.
Router- A Router is a device that works like a bridge but can handle different protocols.
Gateway- A Gateway is a device that connects dissimilar networks.

•  What is a modem? What is its function?
Ans:- A Modem is a computer peripheral that allows us to connect and communicate with other computer through telephone lines. It is short form for Modulation/ Demodulation.
Modem converts Digital signals into Analog signals which can be transmitted through telephone lines and converts back Analog signals to Digital signal to be processed by a computer.
•  What is the difference between a Bridge and a Router?
Ans:- Difference between a router and a Bridge are-
•  A Bridge cannot handle multiple protocols whereas a Router can. A Bridge works with MAC(Media Access Control) address whereas a Router works with IP(Internet Protocol) address.
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