Computer Network And
Communication
1. Objective Questions:
a) Which of the following topologies uses a central hub or switch?
i)
Ring topology
ii)
Star topology ✔
iii)
Bus topology
iv)
Mesh topology
b) What type of IP address uses 128 bits?
i)
IPv1
ii)
IPv4
iii)
IPv6 ✔
iv)
IPX
c) Which wireless media is best for identifying and tracking
items?
i)
Wi-Fi
ii)
RFID ✔
iii)
Bluetooth
iv)
Infrared
d) What is the main purpose of a firewall in a network?
i)
Store data
ii)
Reduce signal interference
iii)
Protect against unauthorized access ✔
iv)
Increase bandwidth
e) What is the shape of a ring topology?
i)
Star
ii)
Linear
iii)
Loop ✔
iv)
Mesh
f) What do you call the technology that allows mobile phones to
share internet with laptops?
i)
Router
ii)
Access Point
iii)
Repeater
iv)
Mobile Hotspot ✔
g) What device helps link networks across cities and countries?
i)
Switch
ii)
Router ✔
iii)
Hub
iv)
Bridge
h) Which generation of mobile technology supports self-driving
cars and IoT?
i)
3G
ii)
4G
iii)
5G ✔
iv)
2G
i) Which communication channel is used in wired networks?
i)
Optical Fiber ✔
ii)
Radio Waves
iii)
Microwaves
iv)
Bluetooth
j) Which device reduces network collisions and works in full
duplex mode?
i)
Hub
ii)
Switch ✔
iii)
Repeater
iv)
Modem
k) What is the main function of a repeater?
i)
Boost weak signals ✔
ii)
Convert signals
iii)
Filter data
iv)
Block interference
l) Which is not a feature of LAN?
i)
Covers small area
ii)
Uses switches or hubs
iii)
Needs satellites ✔
iv)
High-speed transfer
m) What unit is used to measure bandwidth?
i)
Hertz
ii)
Bits per second (bps) ✔
iii)
Kilometers
iv)
Joules
n) What is the smallest type of network for personal gadgets?
i)
LAN
ii)
PAN ✔
iii)
MAN
iv)
WAN
o) What helps in transmitting light within an optical fiber?
i)
Copper
ii)
Total Internal Reflection ✔
iii)
Electricity
iv)
Infrared
p) Which topology fails completely if the backbone cable breaks?
i)
Star
ii)
Ring
iii)
Bus ✔
iv)
Hybrid
q) Which device converts signals between copper and fiber cables?
i)
Repeater
ii)
Bridge
iii)
Media Converter ✔
iv)
Hub
r) Which of the following is not used in wireless media?
i)
Radio Waves
ii)
Infrared
iii)
Coaxial Cable ✔
iv)
Wi-Fi
s) What layer does the hub operate on?
i)
Physical Layer ✔
ii)
Network Layer
iii)
Data Link Layer
iv)
Transport Layer
t) Which of the following is an example of intranet use?
i)
Emailing a client
ii)
Sharing policies within an organization ✔
iii)
Posting on Facebook
iv)
Accessing public websites
a)
OSI = Open Systems
Interconnection
b)
MAN = Metropolitan Area Network
c)
LAN = Local Area
Network
d)
PAN = Personal Area
Network
e)
WAN = Wide Area Network
f)
RJ45 = Registered
Jack 45
g)
STP = Shielded Twisted Pair
h)
UTP = Unshielded Twisted Pair
i)
RFID = Radio
Frequency Identification
j)
DSL = Digital Subscriber Line
k)
Mbps = Megabits per Second
l)
IP = Internet Protocol
m)
IPv4 = Internet
Protocol Version 4
n)
IPv6 = Internet Protocol
Version 6
o)
WWW = World Wide Web
p)
USB = Universal Serial Bus
q)
NIC = Network Interface Card
r)
ISP = Internet Service
Provider
s)
GPS = Global Positioning
System
t)
TCP/IP = Transmission Control
Protocol/Internet Protocol
u)
VoIP = Voice over
Internet Protocol
v)
FTP = File Transfer Protocol
w)
IoT = Internet of Things
x)
Wi-Fi = Wireless Fidelity
y)
MAC = Media Access Control
z)
TV = Television
6. Technical Terms:
a) A device that amplifies weak signals and retransmits them to
improve network coverage.
=
Repeater
b) A protocol suite used for communication over the internet and
similar networks.
=
TCP/IP
c) A private network system used only within an organization.
=
Intranet
d) A type of cable made of thin glass strands used to transmit
data as light.
=
Optical Fiber Cable
e) A network device that connects different networks and selects
the best data path.
=
Router
f) The physical path or medium through which data travels from one
device to another.
=
Transmission Media (Communication Channel)
g) A form of network that connects devices within a city, larger
than a LAN.
=
MAN (Metropolitan Area Network)
h) An address system that uses 32 bits and is separated by dots.
=
IPv4 Address
i) The maximum data transfer speed or capacity of a network
connection.
=
Bandwidth
j) The smallest network used to connect personal devices over
short distances.
=
PAN (Personal Area Network)
k) A type of wireless communication that uses very short-range
radio signals, often for headsets and phones.
=
Bluetooth
l) The type of topology where each device is connected to exactly
two other devices.
=
Ring Topology
m) A wireless signal type that is often blocked by walls and works
only over very short distances, like remote controls.
=
Infrared
n) A smart device that connects computers on a LAN and sends data
only to the correct destination.
=
Switch
o) The arrangement or layout of devices and cables in a computer
network.
=
Network Topology
p) An orbit that allows a satellite to stay fixed above a specific
location on Earth.
=
Geostationary Orbit
q) A device that allows computers with copper cables to connect to
fiber optic networks.
=
Media Converter
r) The process of sending the same data to all devices on a
network.
=
Broadcasting (Broadcast)
s) A connection method that uses telephone lines and is very slow
compared to modern standards.
=
Dial-up Connection
t) A form of network architecture where all devices can serve each
other without a central server.
=
Peer-to-Peer (P2P) Network Architecture.
4. Answer questions
a) What is telecommunication? Give two examples of
telecommunication.
=
Telecommunication is the transmission of information over long distances
through electronic means. Telephone calls and mobile communication are two
examples of telecommunication.
b) What is broadband? State two differences between broadband and
dial-up technology.
=
Broadband is a high-speed internet connection that allows continuous data
transmission. Broadband provides faster internet speed than dial-up technology,
and it allows users to use the telephone and internet simultaneously, whereas
dial-up does not.
c) What is bandwidth? How is it measured?
=
Bandwidth is the maximum amount of data that can be transmitted through a
communication channel in a given period. It is measured in bits per second
(bps), such as Kbps, Mbps, and Gbps.
d) What is throughput? How is it different from bandwidth?
=
Throughput is the actual amount of data successfully transmitted over a
network. Bandwidth refers to the maximum capacity of the network, whereas
throughput refers to the actual data transfer rate achieved.
e) What is a data packet? How does it help in computer networks?
=
A data packet is a small unit of data sent across a network. It helps in
efficient and reliable transmission of data by breaking large data into smaller
manageable pieces.
f) What is frequency in telecommunication? How is it measured?
Frequency
in telecommunication refers to the number of signal cycles that occur in one
second. It is measured in Hertz (Hz).
g) What is the mode of data transmission?
=
The mode of data transmission refers to the direction in which data flows
between communicating devices. The three modes are simplex, half-duplex, and
full-duplex.
h) What is wireless technology? Why is it more popular?
=
Wireless technology is a method of transmitting data without using physical
cables. It is more popular because it provides mobility, convenience, and easy
installation.
i) What is a media converter? Write its function.
=
A media converter is a networking device that converts one type of transmission
media into another. Its main function is to convert electrical signals into
optical signals and vice versa.
j) How does Wi-Fi transmit data?
=
Wi-Fi transmits data through radio waves between wireless devices and a
wireless router or access point.
k) How does data transmit in a computer network?
=
Data is transmitted in a computer network by dividing it into packets, sending
the packets through communication channels, and reassembling them at the
destination.
l) How is a switch different from a hub?
=
A switch sends data only to the intended destination device, whereas a hub
broadcasts data to all connected devices.
m) What is a bridge?
=
A bridge is a networking device that connects two network segments and filters
traffic between them.
n) What is a router? How is it different from a switch?
=
A router is a networking device that connects different networks and forwards
data packets between them. A router uses IP addresses, whereas a switch uses
MAC addresses to transfer data.
o) What is network topology?
=
Network topology is the physical or logical arrangement of devices and
communication links in a network.
p) Write the data flow technique of ring topology.
=
In a ring topology, data flows from one node to another in a circular path,
usually in a single direction.
q) What is LAN? Write its features.
=
A LAN (Local Area Network) is a network that connects devices within a limited
geographical area such as a home, school, or office. Its features include high
speed, low cost, and easy maintenance.
r) Write the features of client-server architecture.
=
Client-server architecture provides centralized management, enhanced security,
efficient resource sharing, and easy maintenance of data.
s) What is a default gateway?
=
A default gateway is a network device, usually a router, that forwards data
from a local network to other networks.
t) What is the Internet? Mention its merits and demerits.
=
The Internet is a global network of interconnected computers. Its merits
include fast communication and easy access to information, while its demerits
include cybercrime and privacy risks.
u) What is an IP address?
=
An IP address is a unique numerical address assigned to a device on a network
for identification and communication purposes.
v) What is a protocol?
=
A protocol is a set of rules and standards that governs communication between
devices in a computer network.
5. Long answers questions:
a. Explain the differences between wired and wireless
communication media with examples.
Wired
communication media use physical cables to transmit data from one device to
another. Examples of wired media include twisted-pair cables, coaxial cables,
and optical fiber cables. Wired communication provides high speed, reliability,
and security. In contrast, wireless communication media transmit data through
electromagnetic waves without using physical cables. Examples of wireless media
include Wi-Fi, Bluetooth, radio waves, and mobile networks. Wireless
communication offers mobility and flexibility but is more susceptible to
interference and security threats.
b. Explain the optical fiber working principle through total
internal reflection.
Optical
fiber works on the principle of total internal reflection. It consists of a
core surrounded by a cladding with a lower refractive index. When light enters
the fiber at a suitable angle, it strikes the boundary between the core and cladding
and is completely reflected back into the core. This process continues
repeatedly, allowing light signals to travel long distances with very little
loss of energy. As a result, optical fibers can transmit data at very high
speeds.
c. Compare the structure, advantages, and disadvantages of bus
topology, star topology, and ring topology.
In
a bus topology, all devices are connected to a single backbone cable. Its main
advantage is that it requires less cable and is inexpensive to install.
However, if the main cable fails, the entire network becomes unavailable.
In
a star topology, all devices are connected to a central hub or switch. Its
major advantage is that failure of one device does not affect the rest of the
network. It is also easy to manage and troubleshoot. However, if the central
hub or switch fails, the entire network stops functioning.
In
a ring topology, each device is connected to two neighboring devices, forming a
circular structure. It provides orderly data transmission and equal access to
the network. However, failure of a single device or connection can disrupt the
entire network.
Bandwidth
is the maximum amount of data that can be transmitted through a communication channel
in a given period of time. It is usually measured in bits per second (bps).
Throughput
is the actual amount of data successfully transmitted over a network in a given
period of time. Throughput is usually lower than bandwidth due to network
congestion, interference, and other factors.
e. Explain the key characteristics and applications of 3G, 4G, and
5G mobile communication technology.
3G
technology provides faster data transmission than earlier generations and
supports services such as video calling, multimedia messaging, and internet
browsing.
4G
technology offers significantly higher speed, lower latency, and better network
performance. It is commonly used for HD video streaming, online gaming, and
video conferencing.
5G
technology provides ultra-high speed, extremely low latency, and the ability to
connect a large number of devices simultaneously. It is used in smart cities,
autonomous vehicles, Internet of Things (IoT) devices, virtual reality, and
advanced industrial applications.
f. Define the functions of repeaters, hubs, and switches in
computer networks.
A
repeater is a networking device that receives weak signals, regenerates them,
and retransmits them to extend the communication distance.
A
hub is a networking device that connects multiple computers and broadcasts
incoming data to all connected devices.
A
switch is a networking device that connects multiple devices and sends data
only to the intended recipient using MAC addresses. This improves network
efficiency and performance.
g. Describe the process of data transmission with radio waves,
microwaves, and infrared in wireless communication technology.
Radio
waves transmit data through electromagnetic signals that can travel long
distances and pass through obstacles such as walls. They are commonly used in
radio broadcasting and Wi-Fi communication.
Microwaves
transmit data through high-frequency electromagnetic waves. They require a
clear line of sight between transmitting and receiving stations and are widely
used in satellite communication and mobile networks.
Infrared
communication transmits data using light waves with frequencies higher than
visible light. Infrared signals cannot pass through walls and are mainly used
in television remote controls and short-range device communication.
h. Describe the application of satellites in telecommunication and
the concept of geostationary orbit.
Satellites
play an important role in telecommunication by enabling television
broadcasting, internet services, mobile communication, weather forecasting, and
global positioning systems (GPS). They help transmit signals over long
distances where terrestrial communication systems are not available.
A
geostationary orbit is an orbit located approximately 35,786 kilometers above
the Earth's equator. A satellite in this orbit revolves around the Earth at the
same speed as the Earth rotates, making it appear stationary from the ground.
This characteristic makes it ideal for communication and broadcasting purposes.
i. Compare LAN, MAN, and WAN based on coverage area, speed, and
cost.
A
Local Area Network (LAN) covers a small geographical area such as a room,
building, or school campus. It provides high speed and is relatively
inexpensive to set up and maintain.
A
Metropolitan Area Network (MAN) covers a city or large town. Its speed is
generally lower than LAN but higher than WAN, and its cost is moderate.
A
Wide Area Network (WAN) covers large geographical areas such as countries or
continents. It is more expensive to establish and maintain, and its speed is
generally lower than LAN due to longer transmission distances.
j. Write the functions of RJ45 connectors and media converters in
networking.
An
RJ45 connector is used to connect Ethernet cables to networking devices such as
computers, switches, and routers. It serves as the standard connector for wired
local area networks.
A
media converter is a device that converts one type of transmission media into
another. For example, it can convert electrical signals in copper cables into
optical signals for fiber optic cables, enabling communication between
different network media.
k. Explain the differences between a client and a server in a
network setup.
A
client is a computer or device that requests services, resources, or
information from another computer on the network. Examples include personal
computers and smartphones accessing websites.
A
server is a powerful computer that provides services, resources, or information
to clients. Examples include web servers, file servers, and database servers.
The server responds to requests from clients and manages network resources.
l. Explain how physical barriers and interference affect wireless
communication.
Physical
barriers such as walls, buildings, trees, and mountains can weaken or block
wireless signals, reducing communication quality and coverage. Similarly,
interference from electronic devices, microwaves, Bluetooth devices, and nearby
wireless networks can disrupt signal transmission. These factors can result in
slower data speeds, poor connectivity, and communication failures.
m. What is a router? Explain the functions of a router in a
computer network.
A
router is a networking device that connects different networks and forwards
data packets between them. It determines the best path for data transmission
using routing tables and network protocols.
The
main functions of a router include connecting local networks to the internet,
forwarding data packets between networks, assigning IP addresses through DHCP,
and providing security through firewall and filtering features.
n. Explain the IPv4 addressing system and its use in computer
networks.
IPv4
(Internet Protocol Version 4) is a system used to identify devices on a network
using a unique 32-bit address. An IPv4 address is divided into four groups of
numbers separated by dots, such as 192.168.1.1.
IPv4
addresses allow devices to communicate with each other by uniquely identifying
the source and destination of data packets. They are essential for routing and
managing communication across computer networks and the internet.
o. Explain the importance of protocols in data communication.
Protocols
are a set of rules and standards that govern communication between devices on a
network. They ensure that data is transmitted accurately, reliably, and
securely. Protocols define how data is formatted, transmitted, received, and
interpreted. Without protocols, devices from different manufacturers would not
be able to communicate effectively. Examples of common protocols include
TCP/IP, HTTP, FTP, and SMTP.
p. Write the key features of each type of network.
A
Local Area Network (LAN) covers a small area, provides high-speed
communication, and is relatively inexpensive to maintain.
A
Metropolitan Area Network (MAN) covers a larger area than a LAN, usually a
city, and connects multiple LANs together.
A
Wide Area Network (WAN) covers very large geographical areas and connects
multiple LANs and MANs across regions, countries, or continents.
q. Explain each type of topology with key features.
A
bus topology connects all devices through a single communication cable called a
backbone. It is simple, cost-effective, and easy to install.
A
star topology connects all devices to a central hub or switch. It is reliable,
easy to manage, and widely used in modern networks.
A
ring topology connects devices in a circular path, where each device is
connected to two neighboring devices. It provides organized data transmission
and equal access to network resources.
A
mesh topology connects every device directly to every other device. It offers
high reliability and fault tolerance but requires more cabling and higher
installation costs.
A
tree topology combines characteristics of bus and star topologies. It is highly
scalable and suitable for large organizations.
r. Write the differences between Client-Server architecture and
Peer-to-Peer network architecture.
In
a client-server architecture, a dedicated server provides services and
resources to multiple client devices. It offers centralized management, better
security, and easier maintenance. This architecture is commonly used in
schools, banks, and large organizations.
In
a peer-to-peer (P2P) architecture, all computers have equal status and can act
as both clients and servers. Resources are shared directly among computers
without a dedicated server. This architecture is less expensive and suitable
for small networks, but it offers lower security and is more difficult to
manage.
For
Knowledge Enhancement
1. Answer
the Following Questions Logically
a)
Your school wants to connect all computers in a new computer lab for sharing
files and internet. Which network topology would you recommend and why?
I
would recommend a Star Topology for the new computer lab. In a star
topology, all computers are connected to a central switch. This topology is
easy to install, manage, and troubleshoot. If one computer or cable fails, the
rest of the network continues to function normally. It also provides better
performance and reliability compared to bus and ring topologies.
b)
A company needs to provide internet access to multiple floors without using
long cables. Which communication medium should they choose?
The
company should choose wireless communication media, specifically Wi-Fi
technology. Wireless communication allows devices on different floors to
connect to the internet without extensive cabling. Access points can be
installed on each floor to provide strong and reliable wireless coverage.
c)
A remote health center wants to send patient data to a hospital in another
city. Which type of network (LAN, MAN, or WAN) would be most suitable?
A Wide
Area Network (WAN) would be the most suitable option. WAN connects
computers and networks over large geographical distances such as cities,
countries, and continents. Since the health center and hospital are located in
different cities, WAN can efficiently transmit patient data between them.
d)
You are setting up a smart home where devices like lights, cameras, and door
locks can be controlled from a smartphone. Which wireless technology would you
use?
I
would use Wi-Fi and Bluetooth technology for a smart home system. Wi-Fi
enables remote control of devices through the internet, while Bluetooth can be
used for short-range communication between devices. These technologies provide
convenient and efficient control of smart home appliances.
2.
Designing a School Network
i)
Decide which network topology you will use in each lab.
I
would use a Star Topology in each computer lab because it is reliable,
easy to maintain, and supports efficient communication among computers.
ii)
Select the communication media for connecting labs and offices.
For
connecting computers within each lab, I would use UTP (Unshielded Twisted
Pair) cables. For connecting different labs and the administrative office
over longer distances, I would use Optical Fiber Cables because they
provide high speed and low signal loss.
iii)
List at least three networking devices needed and explain their functions.
Switch: A
switch connects multiple computers within a network and forwards data only to
the intended device.
Router: A router
connects different networks and provides internet access to all connected
devices.
Access
Point: An access point provides wireless connectivity for laptops,
smartphones, and other wireless devices.
3. IPv4 Addressing Challenge
Address Range: 192.168.10.x
|
Device
Name |
IP
Address |
|
Computer 1 |
192.168.10.1 |
|
Computer 2 |
192.168.10.2 |
|
Computer 3 |
192.168.10.3 |
|
Computer 4 |
192.168.10.4 |
|
Computer 5 |
192.168.10.5 |
|
Printer |
192.168.10.6 |
Subnet Mask:
255.255.255.0
Practical-Based Questions
1.
Networking Devices and Cables
i) Networking Devices
|
Device |
Purpose |
|
Hub |
Broadcasts
data to all connected devices |
|
Switch |
Sends data
only to intended device |
|
Router |
Connects
different networks |
|
Modem |
Connects to
ISP |
|
NIC |
Allows
network communication |
|
Access Point |
Provides
Wi-Fi connectivity |
ii) Networking Cables
|
Cable |
Description |
|
Twisted Pair |
Common LAN
cable (Cat5e/Cat6) |
|
Coaxial |
Used in cable
TV and internet |
|
Fiber Optic |
High-speed
data transmission using light |
iii) Working of Devices and Cables
- Hub: Broadcasts data to
all ports.
- Switch: Uses MAC addresses
to forward data.
- Router: Routes packets
between networks.
- Modem: Converts digital
and analog signals.
- NIC: Provides network
interface.
- Access Point: Extends wireless
network.
iv) Simple Network Diagram
Internet
|
Modem
|
Router
|
Switch
/ | \
PC1 PC2 PC3
2. Find IP Address and Default Gateway
Command:
ipconfig
Example Output:
|
Item |
Example |
|
IPv4 Address |
192.168.1.10 |
|
Default
Gateway |
192.168.1.1 |
Purpose:
IPv4 Address
- Identifies a device on the network.
Default Gateway
- Connects local network to other networks
(Internet).
3. Common Network Commands
i) Ping
ping google.com
Purpose: Tests
connectivity.
ii) IPConfig
ipconfig
Purpose:
Displays network configuration.
iii) Tracert
tracert google.com
Purpose: Shows
path taken by packets.
iv) Nslookup
nslookup google.com
Purpose: Finds
IP address of a domain.
4. RJ45 and Fiber Optic Connectors
RJ45 Connector
- Used with twisted pair cables.
- Common in Ethernet networks.
- Easy and inexpensive.
Fiber Optic Connectors
- SC (Subscriber
Connector)
- ST (Straight Tip)
- LC (Lucent
Connector)
Comparison
|
Feature |
RJ45 |
Fiber
Optic |
|
Speed |
Lower |
Higher |
|
Cost |
Low |
High |
|
Distance |
Up to 100m |
Several
kilometers |
|
Medium |
Electrical
Signal |
Light Signal |
5. Simulating Hub in Cisco Packet Tracer
Steps
- Place a Hub.
- Add three PCs.
- Connect using Copper Straight-Through cables.
- Configure IP addresses.
- Ping PC3 from PC1.
Observation
Hub broadcasts
data to all ports.
6. Simulating Switch in Cisco Packet Tracer
Steps
- Place a Switch.
- Connect three PCs.
- Assign IP addresses.
- Ping PC3 from PC1.
Observation
Switch learns
MAC addresses and forwards data only to the destination port.
7. Connecting Two LANs via One Router
LAN 1
Network:
192.168.1.0/24
|
Device |
IP
Address |
|
PC1 |
192.168.1.2 |
|
PC2 |
192.168.1.3 |
|
Gateway |
192.168.1.1 |
LAN 2
Network:
192.168.2.0/24
|
Device |
IP
Address |
|
PC3 |
192.168.2.2 |
|
PC4 |
192.168.2.3 |
|
Gateway |
192.168.2.1 |
Router Configuration
Fa0/0 = 192.168.1.1
Fa0/1 = 192.168.2.1
Test
ping 192.168.2.2
Successful
reply confirms connectivity.
8. Connecting Two LANs via Two Routers
LAN 1
Network:
192.168.1.0/24
Gateway:
192.168.1.1
LAN 2
Network:
192.168.2.0/24
Gateway:
192.168.2.1
Serial Link
|
Interface |
IP |
|
Router1
S0/0/0 |
10.0.0.1 |
|
Router2 S0/0/0 |
10.0.0.2 |
DCE Clock Rate
clock rate 64000
Test
ping 192.168.2.2
9. Connecting Three LANs via One Router
LAN 1
Network:
192.168.1.0/24
Gateway:
192.168.1.1
LAN 2
Network:
192.168.2.0/24
Gateway:
192.168.2.1
LAN 3
Network:
192.168.3.0/24
Gateway: 192.168.3.1
Router Interfaces
|
Interface |
IP
Address |
|
Fa0/0 |
192.168.1.1 |
|
Fa0/1 |
192.168.2.1 |
|
Fa1/0 |
192.168.3.1 |
Test
ping 192.168.3.2
Successful ping
confirms that all three LANs are connected and communicating properly.
