CHAPTER NO.3 COMPUTER NETWORKS
3.1 INTRODUCTION TO COMPUTER NETWORK
Computer networks are the base of
communication in Information Technology.These are
used in a variety of ways and these can include different types of network. In
simple words, a computer network is a set of
computers that are connected together (using a
media) in a way that they can share information and complete the process.
3.2 NEED OF NETWORKING
To share our files or information from
our computer to another computer we need Computer
networking. In simple terms Networking means communication and sharing. We can
say that a networking means to communicate and sharing an information over a
network. In our routine work we use the things
or services where networking plays an important
role:
Communicating using email, video, instant messaging.
Other methods sharing devices such as printers,
scamers and photocopiers.
Sharing files, sharing software and operating
programs on remote systems
Allowing network users to easily access and maintain
information
3.3 OSI LAYERS
OSI stands for Open Systems Interconnection. It has
been developed by ISO - ‘International Organization of Standardization’, in the
year 1984. It is 7-layer architecture, with each layer having specific
functionality to perform. All these 7 layers work collaboratively to transmit
the data
from one person to another across the globe.As we
have studied that there are the seven OSI layers. Each layer has different
functions.
A list of seven layers are given below:
i, Physical Layer
ii. Data-Link Layer
ili. Network Layer
iv. Transport Layer
v. Session Layer
vi. Presentation Layer
vii. Application Layer
i. Poysical Layer :
The main function of this layer is to transmit the individual bits (0,1)from
one node(any physical device) to another node. It is the lowest layer of the
OSI model. It
establishes, maintains and deactivates the physical
connection in a network.
ii. Data-Link Layer :
Data-Link layer is responsible for transferring of data frames (a sequence of
bits or symbols) without any error. It defines the format of the data on the
network.
It provides a reliable and efficient communication
between two or more devices. It is mainly responsible for the unique
identification of each device that resides on a local network.
iii. Network Layer :
Network Layer manages device addressing, tracking the location of devices on
the network. It determines the best path to move data from source to the
destination
based on the network conditions, the priority of
service, and other factors. The Data link layer is responsible for routing and
forwarding the packets, The protocols used to route the network
traffic are known as Network layer protocols.
Examples of protocols are IP and Ipv6.
iv. Transport Layer :
The Transport layer ensures that messages are transmitted in the order in which
they are sent and there is no duplication of data. The main responsibility of
the
transport layer is to transfer the data completely.
It receives the data from the upper layer and converts them into smaller units
known as segments. This layer can be termed as an end-to-end
layer as it provides a point-to-point connection
between source and destination to deliver the data reliably.
v. Session Layer :
The session layer is the fifth layer, which controls the connections between
multiple computers. The session layer tracks the dialogs between two processes
which can be either half-duplex or full-duplex, which are also called sessions.
Session layer adds some checkpoints when transmitting the data in a sequence,
If some error occurs in the middle
of the transmission of data, then the transmission
takes place again from the checkpoint. This process is known as Synchronization
and recovery.
vi. Presentation Layer :
A Presentation layer is mainly concemed with the syntax and semantics of the
information exchanged between the two systems, It acts as a data translator for
a network. This layer is a part of the operating system that converts the data
from one presentation format to another format, The Presentation layer is also
known as the syntax layer.
vii. Application Layer :
An application layer serves as a window for users and application processes to
access network service. It handles issues such as network transparency,
resource
allocation, etc. An application layer is not an
application, but it performs the application layer functions. This layer
provides the network services to the end-users.
3.4 NETWORE DEVICES
We have already studied about computer network and
OSI layers. Now we will study about the devices that are used in a Network. In
simple terms Network Devices are termed the hardware used in making a network.
The networks can be as small as used in office or home
and some are as big as often used in big buildings
etc. Devices that filter data traffic are called Connectivity Devices.Let's
study about various types of Network Devices in detail:
3.4.1 Hub
A network hub is a node that is used to broadcast
data to every computer or to an Ethernet-based device connected to it. A hub is
basically a multiport repeater. Wires coming from different devices are
connected to a Hub. A Hub cannot filter the data so data
packets are sent to all connected devices.In a
computer network the hubs are categorized in three types such as:
Active Hub : These hubs regenerate our signals as
well as amplify the signal. These are used to extend the maximum distance
between nodes on a network.
Passive Hub : These hubs simply distribute the
signal coming from the previous ports. These hubs relay signals onto the
network without cleaning and boosting them and can't be used to extend the
distance between nodes,
Intelligence hub : It is an advanced version of hub
and it comprises both active and passive hubs, it provides the ability to
manage the network from one central location.This also helps the administrator
to monitor network traffic and you can configure each port on it individually,
due to this advantage it is also known as a manageable hub.
3.4.2 Switch
It is a small device that is used to
transfer data packets between multiple network
devices such as computers,
routers, servers or other switches. In simple words
a switch works like a
multiport bridge, it has a buffer that is used to boost
its efficiency and
performance of a switch The switch can also perform
any type of error-checking
before forwarding the data, this advantage makes it
very efficient as it does not forward packets that have errors and forward good
packets selectively to correct port only.
3.4.3 Routers
Router is also an important hardware device and it
works as a gateway of networks responsible for keeping data flowing between
networks and also keep networks connected to the Internet. Moreover a router is
a device like a switch that routes data packets based on their IP addresses,
Router is mainly a Network Layer device.
Functions of a Router : The router basically
performs two major functions:
Forwarding : Router receives the packets from its
input ports, checks it header information and looks up to the routing table to
find the appropriate output port to dump the packets.
Routing : Itis the process by which the router
determines that what would be the best path for the packet to reach at the
destination without any loss of information.
3.4.4 Repeater
A repeater is a network device that is used for
regenerating the signal and then transmit. It regenerate the signal over the
same network before the signal
becomes too weak or gets corupted. The repeaters do
not amplify the signal because when the signal becomes weak, they copy the
signal bit by bit and
regenerate it at the original strength. A repeater
is only a 2 port Network Device.
3.4.5 Bridge
A bridge is such type of device that can be used in
computer networks to interconnect two LANs together and other separate network
segments.It uses the MAC address information in
forwarding data packets. Only the data that needs to
be sent across the bridge to the next network segment is forwarded. It has a
single input and single output port.
Types of Bridges :
Transparent Basic Bridge : This bridge is the
simplest type of bridge. Actually it stays transparent or invisible to the
other devices on the network. Transparent bridge
can store data briefly(the details of its source and
destination) before forwarding to the next network.
Source Routing Bridge : In these bridges, routing
operation is performed by source station and the frame specifies which route to
follow. This data is transferred by sending a special frame called discovery
frame, which spreads through the entire
network using all possible paths to destination.
3.4.6 Gateway
A gateway is a component that is part of two
networks, These networks use different protocols. The gateway translates one
protocol into the other. Therefore gateway is also called
protocol converter and can operate at any network
layer. The activity of a gateway is more complex than that of the router or
switch because router and switch communicates using more than one protocol.For
basic Internet connections at home, the gateway is the Internet Service
Provider that gives you
access to the entire Internet.
3.4.7 Brouter
A Brouter is a combination of a Bridge and a Router.
It functions like a bridge and a router.A Brouter connects the networks which
use different protocols. It can be programmed to work
only as a bridge or only as a router. Working as
router, it is capable of routing packets across networks and working as bridge,
it is capable of filtering local area network traffic.
3.5 COMMUNICATION MEDIA
The word communication defines the tool or the means
of delivering and receiving data or information such as Telecommunication.
In telecommunication, these means are
transmission and storage tools or channels for data storage and transmission.
Various transmission media can be used for transfer of data, These transmission
media may be of two types:
Guided Media
Unguided Media
Let's study about various types of transmission
media in brief:
3.5.1 Guided Media
In guided media the data is transmitted using
cabling system that has a fixed path. For example, copper wires, fiber optic
wires, etc.
3.5.1.1 Twisted Pair Cable :
A twisted pair cable contains two separate insulated copper wires,which are
twisted together and it run in parallel.One of the wires is used to transmit
data and the other is the ground reference.The two insulated
copper wires are twisted around each other just to
reduce crosstalk or electromagnetic induction between these pairs of wires.
There are two types of twisted pair
cables:
Unshielded Twisted Pair (UTP) : These generally comprise of wires and insulators.
Shielded Twisted Pair (STP) : They have a braided
wired mesh that encases each pair of Twisted pair comes with each pair uniquely
colour coded when it is packaged in multiple pairs. For
different purposes such as analog, digital and
Ethernet,different pair is required.Copper wires are the most common wires used
for transmitting signals because of good performance at low costs.Advantages of
twisted pair cable : The twisted pair cable is the oldest one used and most
popular cables all over the world. they offer such as:
These cables can be used both for analog and digital
transmissions.
Least expensive for short distances.
Entire network does not go down if a part of network
is damaged.
Disadvantages of twisted pair cable : With its many
advantages, twisted pair cables offer some disadvantages too such as:-
The Signal cannot travel long distances without
using repeaters
High error rate for distances greater than 100m
Very thin and hence breaks easily and not suitable
for broadband connections
3.5.1.2 Coaxial Cable :
Coaxial
cable is a two conductor electrical cable consisting
of a centre conductor and an outer conductor with an insulating spacer between
the two. Coaxial cables are copper cables with better shielding than twisted
pair cables, so that transmitted signals may travel longer distances at higher
speeds, A coaxial cable consists of these layers, starting from the innermost :
1. Core wire is of stiff copper material, so it's
not easy to bend it if necessary.
2. Insulating material surrounding the core
3. Closely woven braided mesh of conducting material
surrounding the insulator The coaxial cables are widely used for cable TV
connections and LANs.
Advantages of Coaxial Cables :
No effect on signals of disturbance from outer side.
Thick coaxial cable has an extra protective plastic
cover that help to keep moisture away.
Can be used for both analog and digital signals.
Easy to install and maintain.
Disadvantages of Coaxial Cables :
These cables are expensive as compared to twisted
pair cables.
These are not compatible with twisted pair cables.
Thick coaxial is that it does not bend easily and is
difficult to install.
3.5.L3 Optical Fibre : An optical fibre cable has a number of optical
fibres (a thin flexible fibre with a glass core)
bundled together which are
normally covered in plastic covers or shields. Optical cables are used to
transfer digital data signals in the form of light
up to the distances of hundreds of miles with a higher throughput rates in
comparison to other electrical communication cables.
Optical fibre cable is widely used in fibre optic
communications. Light Emitting Diodes (LEDs) or Laser Diodes (LDs) emit light
waves at the source, which is read by a detector at the
other end, All optical fibres use a core of
hair-like transparent silicon covered with less refractive indexed cladding.
Optical fibres are very sensitive So, it is normally covered with a
high-strength, lightweight protective material. Each fibre is made up of these
three layers,starting with the innermost layer ?
Core made of high quality silica glass or plastic
Cladding made of high quality silica glass or
plastic.
External protective outer covering called buffer
It must be noted that both core and cladding are
made of similar material. However, as refractive index (the ratio of the
velocity of light in a vacuum to its velocity in a specified medium.) of the
cladding is lower and any light wave distracted from core is reflected back due
to total internal reflection.
Advantages of Optical Fibre : Optical fibre is fast
replacing copper wires because of these advantages that it offers ?
One single mode fibre can replace a wire made of
heavy and large copper.
Higher bandwidth.
Suitable for industrial and noisy areas.
Data Signals can be sent to a long distance without
weakening.
Disadvantages of Optical Fibre: Despite long segment
lengths and high bandwidth,using optical fibre may not be a viable option for
every one due to these disadvantages :
Optical fibre cables are expensive.
The optical fiber are highly polished to allow light
to pass with a little loss.
Light waves are unidirectional, so two frequencies
are required for full duplex transmission.
3.5.2. Unguided Media
The media that doesn't use any type of directed or
guided media is called unguided media.Unguided media transfer the data using
electromagnetic waves without using a physical conductor. This type of
communication is often referred to as wireless communication. Signals are
normally broadcast using through free space(or in a few cases, water) and thus
are available
to anyone who has a device capable of receiving
them.
We can categorize wireless transmission into the
following groups:
Infrared
NEC
Bluetooth
Wi-Fi
Radio Waves
Micro waves
Satellites
Let's study all of these in detail as below:
3.5.2.1 Infrared :
Infrared (IR) is a type of wireless mobile technology that is used for
communication over a short range of field. IR communication has some major
limitations such as it requires line-of-sight, has a short transmission range
and is unable to penetrate through walls.
IR cannot be used for long - range communication.
Because Its use is limited within a closed space and they do not need any
government permissions for their applications.
Applications of Infrared Waves in Communications:
Remote controls for television, stereos and other
home appliances.
Wireless LANs
Wireless modem, keyboard, mouse, printer etc
Fire detectors
Night vision systems
Intrusion detection systems
Motion detectors
3.5.2.2 NFC (Near Field Communication)
: NFC technology is a new technology that is used for data transfer. It is a contactless way in which NFC devices interact also bears similarity to Bluetooth It can be employed in contactless payment systems. It also provides a compact way to communicate information, which may be used for advertising or social media purposes.
NFC tags or cards are passive devices. They store
data that can be retrieved by active NFC devices. The most common example of
NFC use involves a contactless payment system, in
which a smartphone can be swiped at an NFC reader
(which are increasingly being installed Dear a store's cash register) to make a
contactless payment. The NFC device transmits information about the smartphone
user's credit card, In this case, the reader is the NFC tag, while the smartphone
acts as an NFC device. Because NFC must occur within short range, the
transaction is considered secure.
3.5.2.3 Bluetooth : Bluetooth is a type of radio communication technology that enables a low-power and a short distance wireless networking between phones, computers and other network devices.Two Bluetooth devices are connected to each other while using a process called pairing. When you press a button or select a menu option on the unit, a Bluetooth device initiates a new connection. The pairing details may vary depending on the type of device. PCs and other devices can also be enabled through the use of Bluetooth dongles. Bluetooth networks use a dynamic topology called Piconet.
Bluetooth cover only short distances, typically up
to 30 feet until the most recent standard
3.5.2.4 Wi-Fi :
Wi-Fi is one of a popular wireless networking technology. Wi-Fi stands for
“wireless fidelity". It is commonly called as wireless LAN (local area
network). Wi-Fi allows local area networks to operate without cable and wiring.
It is becoming
popular choice for home and business networks, By
using this technology we can exchange the information between two or more
devices that are of same network.
Wi-Fi has been developed for mobile computing
devices, such has laptops, but it is now using for mobile applications and
consumer electronics like televisions, DVD players and even in digital cameras.
3.5.2.5 Radio waves :
Radio waves are
a type of electromagnetic waves. These waves are
famous for their use in communication technologies, such as television, mobile
phones and radios. These devices receive radio waves and convert them to
mechanical
vibrations in the speaker to create sound waves.
When an antenna transports radio waves they are propagated in all the directions
in free space.
It means that, the sending and receiving antennas do
not have to be aligned. The frequency refers to number of waves per second, it
is measured in hertz (Hz).
Applications of Radio waves:
Radio waves are useful for multicasting in case
where one sender but have many
receivers.
Examples of radio waves are television, AM and FM
radio, cordless phones, and
paging.
Advantages and disadvantages of Radio
waves:
Radio waves are very powerful waves. These waves are
easy to generate and penetrate through buildings. These waves also can travel
at long distances, Radio waves cover a large
area.
3.5.2.6 Micro Waves :
Another important type of waves is microwave. Microwave is defined as the part
of the electromagnetic spectrum (It is a type of light, that a human eye can't
see it) with large infrared waves and short radio
waves. An example of microwave is a type of cooking that uses energy waves to
cook food i.e. microwave cooking. If we talk about the word Microwave then the
prefix "micro-" indicates that microwaves are "small"
because they have shorter wavelengths as compared to waves used in typical
radio broadcasting.
Microwave Transmission is classified in
two categories as follows:
Terrestrial Microwave
Satellite Microwave
Applications of Micro Waves : Due to the
unidirectional properties of Micro Waves, they are very useful when unicast
(one-to-one) communication is needed between the sender and
the receiver. Cellular phones, satellite networks,
and wireless LANs are using Micro Waves.
Advantages of microwaves ;: Microwaves are
inexpensive for short distance as it requires a higher tower for a longer
distance.
Microwave transmission is cheaper than using cables.
Microwave transmission provides easy communication.
Disadvantages of microwaves:
Bandwidth is limited in microwave transmission.
Asignal can be moved out of phase and any
environmental change such as rain, wind can distort the signal so these signals
are susceptible to weather conditions.
3.5.2.7 Terrestrial Microwave :
These microwave transmission are sent between two microwave stations situated
on earth. It is the most common form of long distance communication.
3.5.2.8 Satellite Microwave : A satellite is
an entity that revolves around the earth at a certain height. Satellite
communication offers more flexibility than fibre optic and cable
systems. We can transmit signals from any point on
the globe by using satellite transmission.
Advantages of Satellite Microwave:
Coverage of Satellite Microwave is more that Ground Microwave.
It is used in a variety of applications such as
radio/TV signal broadcasting, weather forecasting, radio/TV signal
broadcasting, mobile communication etc.
Disadvantages of Satellite Microwave:
The manufacturing cost is very high of satellite and
very expensive to launch a satellite.
Transmission can go down in bad weather.
3.6 COMMUNICATION MODES
Communication mode is also called theTransmission
Modes. The mechanism of transferring data or information between two linked
devices connected over a network is referred to as
Transmission Modes. It tells the direction of signal
flow between the two linked devices.Categories of Transmission Modes: There are
three categories of transmission mode:
3.6.1 Simplex Mode
3.6.2 Half-Duplex Mode
3.63 Full-Duplex Mode
3.6.1 Simplex Mode
In this type of transmission mode, communication is unidirectional that is data can be sent only in one direction. This means you cannot send a message back to the sender just like a one- way street.
From the two devices, only one can send or transmit on a link and the other can only receive the data,
Example : A simplex transmission can be seen between
a computer and a keyboard a signal is sent from a keyboard but no signal can't
be sent back to keyboard. A television broadcast, television and remote sare
also examples of simplex transmission.
Advantage of Simplex mode:
In this mode, the station can utilize the entire
capacity of the communication channel,so there can be transmitted more data at
a time.
Disadvantage of Simplex mode:
Mainly communications require the two-way exchange
of data but it is unidirectional,so it has no inter-communication between
devices,
3.6.2 Half-Duplex Mode
In a Half-duplex mode, each station can transmit and receive the data as well. The flow of messages can be in both directions, but not simultaneously, The entire capacity (bandwidth) of the communication channel is utilized
in one direction at a time. In half-duplex mode, the
sender sends data and wait for its acknowledgment and if there is any error so
that receiver can demand it to retransmit that data, By this error detection is
possible.
An example of half-duplex mode
is Walkie-talkic. In Walkie-talkic, from one side a
speaker speaks, and from the other side, someone listens. After a pause, the
other speaks and first-person listens.
Advantage of Half-duplex mode:
In half-duplex mode, the entire capacity of a
channel is taken over by whichever of the two devices is transmitting at the
same time.
Disadvantage of Half-Duplex mode:
It causes the delay in sending the data at the
correct time as when one device is sending the data, then another has to wait
to send data.
3.6.3 Full Duplex Mode
In Full duplex mode, the communication is
bi-directional, i.¢., the data flow in both the directions at the same time.
From both the ends receipt and transmission of data is possible at the same time. Full-duplex mode has two physically separate transmission paths.It is one of the fastest mode of communication between devices,
Example : On a mobile phone, two people sare
communicating with each other both can talk and listen to each other at the
same time, this is the full-duplex transmission.
Advantage of Full-duplex mode:
Both the stations can send and receive the data at
the same time, so the capacity of link can be shared.
Disadvantage of Full-duplex mode:
The bandwidth of the communication channel is
divided into two parts if there is no dedicated path exists between the
devices.
3.7 NETWORE SHARING
Network sharing is a feature of a network that allows resources to be shared over a network, that can be files, documents, folders,media, etc. These are made accessible to other users/computers over a network.
Network sharing enables access to
information by more than one person through more
than one device at the same or at different times. By connecting a device to a
network, other users/devices in the network can share and exchange information
through this network, Network sharing is also known as shared resources,
3.7.1 Printer Sharing
Printer sharing is the process of allowing multiple
computers and devices connected to the same network to access one or more
printers. Each node or device on the network can print to
apy shared printer and, to some extent, make changes
to the printer settings, depending on the permissions set by the administrator
for each user.If a printer is attached to a computer that supports printer
sharing, the computer can share that printer with other computers on the same
network, It does not matter whether the shared
printer is old or new.
How to share a printer:
From the Control Panel, open Devices and Printers.
Right-click the printer you want to share. Click
Printer Properties, and then select the Sharing tab.
Check Share this Printer. Under Share name, select a
shared name to identify the printer. Click OK.
3.8 PROTOCOLS
Network Protocols are a set of rules governing
exchange of information in an easy, reliable and secure way. Before we discuss
the most common protocols used to transmit and receive
data over a network, we need to understand how a
network is logically organized or designed.The most popular model used to
establish open communication between two systems is the Open Systems Interface
(OSI) model proposed by ISO.
3.8.1 TCP/IP
TCPAP stands for Transmission Control
Protocol/Internet Protocol. TCP/IP is a set of layered protocols used for
communication over the Internet. Its communication model is,client-server
model. A computer that sends a request is the client and a computer to which
the request is sent is the server.
TCP/IP bas four layers:
Application layer : Application layer protocols like
HTTP and FTP are used.
Transport layer : Data is transmitted in the form of
datagrams using the
Transmission Control Protocol (TCP). TCP is
responsible for breaking up data at the client side and then reassembling it on
the server side.
Network layer : Network layer connection is
established using Internet Protocol (IP)at the network layer. Every machine
connected to the Internet is assigned an address
called IP address by the protocol to easily identify
source and destination machines.
Data link layer : The data link layer is called the
second layer of Open System Interconnection or OSI. It is responsible for
transmitting the data within a Physical network link. It is considered the most
reliable system for transmitting data from one node to another node.
3.8.2 FTP
FTP stands for File Transfer Protocol. It is used to
transfer large number of files between the computers or over the network. The
protocol that handles these requests is File Transfer
Protocol or FTP.
3.8.3 PPP
Point to Point Protocol or PPP is a data link layer
protocol that enables transmission of TCP/IP traffic over serial connection,
like telephone line. Using PPP, home users can avail
Internet connection over telephone lines,
3.8.4 SMTP
SMTP (Simple Mail Transfer Protocol) is a TCP/IP
protocol used in sending and receiving e-mail. However, since it is limited in
its ability to queue messages at the receiving end, it is
usually used with one of two other protocols, POP3
(Post Office Protocol) or IMAP (Internet Message Access Protocol), that let the
user save messages in a server mailbox and download them periodically from the
server. In other words, users typically use a program that uses SMTP for sending
e-mail and either POP3 or IMAP for receiving e-mail.
3.8.5 POP/IMAP
Post Office Protocol version (POP3) is a standard
mail protocol used to receive emails from a remote server to a local email
client. POP allows you to download email messages on your local computer and
read them even when you are offline. Note, that when you use POP to connect to
your email account, messages ate downloaded locally and removed from the email
server. This means that if you access your account from multiple locations, which
may not be the best option for you. On the other hand, if you use POP, your
messages are stored on your
The Internet Message Access Protocol (IMAP) is a
mail protocol used for accessing email on a remote web server from a local
client. IMAP and POP3 are the two most commonly used Internet mail protocols
for retrieving emails. Both protecols are supported by all modern email clients
and web servers.
POP protocol provides the facility to access email
only from one application there as IMAP allows simultaneous access by multiple
clients. This is why IMAP is more suitable for you if you're going to access
your email from different locations or if your messages are managed by multiple
users.
3.8.6 HTTP
HTTP means Hypertext Transfer Protocol. HTTP is the
underlying protocol used by the World Wide Web and this protocol defines how
messages are formatted and transmitted, and what actions Web servers and
browsers should take in response to various commands. For
example, when you enter a URL in your browser, this
actually sends an HTTP command to the Web server directing it to fetch and
transmit the requested Web page. The other main standard
that controls how the World Wide Web works is HTML,
which covers how Web pages are formatted and displayed.
3.9 NETWORK COMPONENT ADDRESSES
3.9.1 MAC Address
Stands for “Media Access Control Address," and
it does not referred to Macintosh Computers. A MAC address is a hardware
identification number that uniquely identifies each device on a network. The
MAC address is manufactured into every network card, such as an Ethernet card
or Wi-Fi card, and therefore it cannot be changed. Because there are millions
of
Network-enabled devices are in world and each device
has its own Unique MAC address. For this each MAC address is designed using 6
different two hexadecimal characters separated
with colon,For example, an Ethernet card may have a
MAC address of 00:00:0A:BB:28:FC. You do not need to know this address, as is
automatically recognized by most networks.
3.9.2 IP Address
Every machine on a network has a unique identifier.
Just as you would address a letter to send in the mail, computers use the
unique identifier to send data to specific computers on a network. Most
networks today, including all computers on the Internet, use the TCP/IP
protocol as the standard for how to communicate on the network. In the TCP/IP
protocol, the unique identifier for a computer is called its IP address,
There are two standards for IP addresses: IP Version
4 (IPv4) and IP Version 6 (IPv6). All computers with IP addresses have an IPv4
address, and many are starting to use the new IPv6
address system as well. Here's what these two
address types mean:
IPv4 uses 32 binary bits to create a single unique
address on the network. An IPv4 address is expressed by four numbers separated
by dots. Each number is the decimal (base-10)representation for an eight-digit
binary (base-2) number, also called an octet. For example:216.29.62.135.
IPv6 uses 128 binary bits to create a single unique
address on the network, An IPv6 address is expressed by eight groups of
hexadecimal (base-16) numbers separated by colons.
Pointseho
1. A computer network is a set of computers that are
connected together.
2. The devices that filter traffic are called
connectivity devices
3. A repeater is a network device that is used for
regenerating the signal and transmitting.
4. A hub is basically a multiport repeater,
5. In a computer network, the hubs are categorized
in three types such as; Active Hub,Passive Hub and Intelligence Hub
6. Ina network, a Bridge is a device that is used to
connect two separate Ethernet networks into one extended Ethemet.
7. A Bridge is a2 port device.
8. A switch is like a multiport bridge with a buffer
that can boost its efficiency and performance.
9. A router is a device like a switch that routes
data packets based on their IP addresses.
10. A Brouter is a combination of a Bridge and a
Router.
11. Transmission media is of two types: Guided and
Un-guided.
12. Optical cables are used to transfer digital data
signals in the form of light up to the distances of hundreds of miles.
13. The media that doesn't use any type of directed
or guided media is called unguided media,
14. Two Bluetooth devices are connected to each
other while using a process called
15. Microwave Transmission is classified in two
categories as follows: such as Terrestrial
Microwave and Satellite Microwave.
16. Satellite communication offers more flexibility
than fiber optic and cable systems.
17. Communication mode is also called the
Transmission Modes.
18. There are three categories of transmission mode:
Simplex Mode, Half-Duplex Mode and Full-Duplex Mode
19. Network sharing is a feature of a network that
allows resources to be shared over a network, they can be files, documents,
folders, media, etc.
20. Network Protocols are a set of rules governing
exchange of information in an easy,reliable and secure way.
Part-A
1. Multiple Choice Questions:
1. A computer is a set of computers that
are connected together.
a. Network
b. System
c. Protocol
d, Internet
2 A______is basically a multiport repeater.
a. Hub
b. Switch
c. Router
d. Bridge
3. A is a 2 port device.
a, Hub
b. Switch
c. Router
d. Bridge
4. Wi-Fi stands for.
a. Wireless Field
b. Wireless Fidelity
c. Wire Fire
d. Wire Fidelity
5. OA is a combination of a Bridge and a
Router.
a. Switch
b. Bridge
c, Hub
d, Brouter
2. Write Full Forms
I UTP IL FIP
I. SMTP IV. POP
V. HITP VI. MAC
Part-B
3. Short Answer Type Questions. (Write
the answers in 4-5 lines)
1. What is a Network?
2 Write different types of OSI layers.
3. What is a Bridge?
4. Why do we need a network?
5. What is guided media?
6. What is un-guided media?
7. Define Protocol.
Part-C
5. Long Answer Type Questions. (Write
the answers in 10-15 lines)
1. What are network devices? Describe any three
network devices.
2 What is Unguided Media. Write any two media.
3 What is a twisted pair cable? Define its
advantages and disadvantages.
4. What is Fibre Optic Cable? Define its advantages
and disadvantages.
5. What is Communication Mode? Define its types.
LAS AGT WR?
1. Draw a chat to represent different types of
Communication Media.
2. Draw a chart to represent different types of
Network Devices.
