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GNDU QUESTION PAPERS 2024
B.com 6
th
SEMESTER
WINDOWS AND NETWORKING
(Group III: Computer Applicaons & E-Business)
Time Allowed: 3 Hours Maximum Marks: 50
Note: Aempt Five quesons in all, selecng at least One queson from each secon. The
Fih queson may be aempted from any Secon. All quesons carry equal marks.
SECTION-A
1. What is disk operang system? Explain various internal and external commands of DOS.
2. (a) Write a note on the following:
(i) Cryptology
(ii) Start Menu.
(b) Explain various funcons of operang system.
SECTION-B
3. (a) How to search les with same extension using windows search command?
(b) What all sengs can the user congure using windows display sengs?
4. (a) Write step by step process to restore deleted les from recycle bin.
(b) What is the signicance of windows display sengs?
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SECTION-C
5. Explain dierent transmission modes with help of suitable examples.
6. What is mulplexing? Explain its dierent types.
SECTION-D
7. How one can secure his system from various network security 10 threats?
8. (a) What is a rewall? Explain various benets associated 5 with it.
(b) Write a short note on spoong.
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GNDU ANSWER PAPERS 2024
B.com 6
th
SEMESTER
WINDOWS AND NETWORKING
(Group III: Computer Applicaons & E-Business)
Time Allowed: 3 Hours Maximum Marks: 50
Note: Aempt Five quesons in all, selecng at least One queson from each secon. The
Fih queson may be aempted from any Secon. All quesons carry equal marks.
SECTION-A
1. What is disk operang system? Explain various internal and external commands of DOS.
Ans: Disk Operating System (DOS)
What is DOS?
The Disk Operating System (DOS) is one of the earliest types of operating systems used in
computers. It acts as a bridge between the user and the computer hardware, allowing
users to perform tasks like opening files, copying data, and running programs.
Imagine DOS like a manager in an office. You (the user) give instructions, and DOS tells the
computer what to do.
Unlike modern operating systems like Windows or macOS, DOS is command-based,
meaning you have to type instructions (commands) instead of clicking icons.
Basic Working of DOS
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In simple terms:
User → DOS (Operating System) → Computer Hardware
• You type a command
• DOS understands it
• DOS tells the hardware what action to perform
Features of DOS
• Single-user system (one person at a time)
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• Command-line interface (CLI)
• Lightweight and fast
• Works mainly with disk storage (hence the name)
Types of DOS Commands
DOS commands are divided into two main categories:
1. Internal Commands
2. External Commands
Let’s understand both in a very easy way
1. Internal Commands
What are Internal Commands?
Internal commands are built into the DOS system itself.
They are stored in memory and are always available.
Think of them like basic tools always in your pocket.
Examples of Internal Commands
1. DIR (Directory)
• Used to show files and folders
DIR
It displays all files in the current directory.
2. CD (Change Directory)
• Used to move between folders
CD foldername
Example:
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CD Documents
3. CLS (Clear Screen)
• Clears the command screen
CLS
4. COPY
• Used to copy files
COPY file1.txt file2.txt
5. DEL (Delete)
• Deletes files
DEL file.txt
6. DATE
• Displays or changes the system date
DATE
7. TIME
• Displays or changes time
TIME
Key Point:
Internal commands are fast because they are already loaded in memory.
2. External Commands
What are External Commands?
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External commands are not stored in memory permanently.
They are stored as separate files on disk and loaded only when needed.
Think of them like tools kept in a toolbox—you bring them when needed.
Examples of External Commands
1. FORMAT
• Used to format a disk
FORMAT C:
2. CHKDSK (Check Disk)
• Checks disk for errors
CHKDSK
3. DISKCOPY
• Copies one disk to another
DISKCOPY A: B:
4. TREE
• Displays folder structure in a tree format
TREE
5. XCOPY
• Copies files and directories (advanced copy)
XCOPY source destination
6. EDIT
• Opens a text editor
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EDIT file.txt
7. ATTRIB
• Changes file attributes
ATTRIB +R file.txt
Key Point:
External commands require separate files (like .EXE or .COM) to run.
Difference Between Internal and External Commands
Feature
Internal Commands
External Commands
Stored in
Memory
Disk
Availability
Always available
Loaded when needed
Speed
Faster
Slightly slower
Examples
DIR, CD, CLS
FORMAT, CHKDSK, TREE
Real-Life Example
Think of DOS like a kitchen
• Internal commands = Basic items always available (salt, sugar, water)
• External commands = Special items stored outside (spices, special tools)
You use basic items quickly, but for special tasks, you go and get extra tools.
Conclusion
The Disk Operating System (DOS) is a simple yet powerful operating system that laid the
foundation for modern systems. Even though it may look outdated today, understanding
DOS helps students learn how computers actually work behind the scenes.
• It uses commands instead of graphics
• Commands are divided into:
o Internal (built-in, always ready)
o External (stored separately, used when needed)
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By learning DOS commands, students gain a strong base in computer fundamentals, which
is very useful for programming, system operations, and understanding advanced operating
systems.
2. (a) Write a note on the following:
(i) Cryptology
(ii) Start Menu.
(b) Explain various funcons of operang system.
Ans: Part (a) Notes
(i) Cryptology
Cryptology is the science of secure communication. It combines two branches:
• Cryptography – the art of creating codes and ciphers to protect information.
• Cryptanalysis – the art of breaking those codes and uncovering hidden information.
Everyday Example
When you send a WhatsApp message, it is encrypted using cryptographic algorithms. Only
the intended recipient can decrypt and read it. Hackers trying to break into the system are
essentially attempting cryptanalysis.
Importance
• Protects sensitive data (banking, military, personal communication).
• Ensures confidentiality, integrity, and authenticity.
• Forms the backbone of cybersecurity in the digital age.
(ii) Start Menu
The Start Menu is a central feature of Microsoft Windows operating systems. It acts as the
gateway to applications, files, and system settings.
Features
• Program Access: Lists installed applications.
• Search Bar: Quickly finds files, apps, or settings.
• Power Options: Shut down, restart, or sleep the computer.
• Customization: Pin favorite apps for easy access.
Everyday Example
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When you click the Windows icon at the bottom-left corner of your screen, the Start Menu
opens. From there, you can launch Word, browse documents, or adjust system settings.
Part (b) Functions of Operating System
An Operating System (OS) is the software that acts as a bridge between the user and the
computer hardware. Without it, hardware is just a collection of circuits. The OS makes the
computer usable.
1. Process Management
The OS manages all running programs (processes).
• Allocates CPU time to each process.
• Ensures multitasking (running multiple apps simultaneously).
• Handles process creation, execution, and termination.
Example: When you stream music while browsing the web, the OS ensures both processes
get CPU time without crashing.
2. Memory Management
The OS manages RAM (Random Access Memory).
• Allocates memory to processes.
• Keeps track of which memory is free or occupied.
• Prevents one program from interfering with another’s memory space.
Example: When you open multiple tabs in Chrome, the OS allocates memory to each tab.
3. File System Management
The OS organizes data into files and folders.
• Provides access methods (read, write, delete).
• Maintains directories for easy navigation.
• Ensures security with permissions.
Example: Saving a Word document in “Documents” folder is handled by the OS’s file system.
4. Device Management
The OS controls hardware devices like printers, keyboards, and USB drives.
• Uses device drivers to communicate with hardware.
• Manages input/output operations.
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Example: When you print a file, the OS sends data to the printer driver, which translates it
into printer commands.
5. Security and Access Control
The OS protects the system from unauthorized access.
• User authentication (passwords, biometrics).
• File permissions (read/write/execute).
• Firewalls and encryption support.
Example: Logging into Windows with your password is part of OS security.
6. User Interface
The OS provides a user-friendly interface.
• Graphical User Interface (GUI): Icons, windows, menus.
• Command-Line Interface (CLI): Text-based commands.
Example: Windows uses GUI, while Linux can use both GUI and CLI.
7. Networking
The OS manages network connections.
• Provides protocols for communication.
• Enables sharing of resources across networks.
Example: Connecting to Wi-Fi and browsing the internet is managed by the OS.
8. Error Detection and Handling
The OS detects errors in hardware or software.
• Provides alerts or logs.
• Attempts recovery or safe shutdown.
Example: If a program crashes, the OS shows an error message and prevents system-wide
failure.
Diagram: Functions of Operating System
+-------------------+
| User Interface |
+-------------------+
| Process Mgmt |
| Memory Mgmt |
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| File Mgmt |
| Device Mgmt |
| Security |
| Networking |
| Error Handling |
+-------------------+
| Hardware Layer |
+-------------------+
Why Operating Systems Matter
Without an OS:
• Users couldn’t interact with hardware easily.
• Programs wouldn’t run smoothly.
• Security and resource management would collapse.
Operating systems like Windows, Linux, macOS, and Android make modern computing
possible.
Final Thought
This question ties together three important aspects of computing:
• Cryptology ensures secure communication.
• Start Menu provides easy access to system resources.
• Operating System functions make the entire computer usable, secure, and efficient.
SECTION-B
3. (a) How to search les with same extension using windows search command?
(b) What all sengs can the user congure using windows display sengs?
Ans: 3. (a) How to search files with same extension using Windows search command?
Imagine your computer is like a big library . Inside it, there are thousands of files—
documents, images, videos, songs, etc. Now suppose you want to find only PDF files or only
MP3 songs. Searching one by one would be tiring, right?
That’s where the Windows Search feature helps you.
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What is File Extension?
Before searching, you must understand file extensions.
A file extension is the last part of a file name, like:
• .pdf → Document file
• .jpg → Image file
• .mp3 → Audio file
• .docx → Word file
How Windows Search Works
Windows has a built-in search system in Microsoft Windows that allows you to find files
quickly using keywords and filters.
Method to Search Files with Same Extension
Step-by-Step Process:
1. Open File Explorer
(Press Windows + E)
2. Go to the folder or drive where you want to search
(Example: This PC, Documents, Downloads)
3. Click on the Search bar (top-right corner)
4. Type the extension like this:
*.pdf
or
*.jpg
What does * mean?
The * is called a wildcard character.
It means “anything”.
So:
• *.pdf → finds all PDF files
• *.mp3 → finds all music files
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• *.docx → finds all Word documents
Simple Diagram to Understand
Search Bar Input: *.pdf
Windows Search Process:
--------------------------------
| File1.pdf ✔ Found |
| Image.jpg ✘ Not matched |
| Notes.pdf ✔ Found |
| Song.mp3 ✘ Not matched |
--------------------------------
Result: Only .pdf files shown
Advanced Search Tips
You can also combine filters:
• *.pdf date:today → PDF files created today
• *.jpg size:>1MB → Images larger than 1MB
• report *.docx → Word files with "report" in name
Why is this useful?
• Saves time
• Helps manage large data
• Makes work faster and efficient
3. (b) What settings can the user configure using Windows Display Settings?
Now let’s move to the second part.
Think of your computer screen like your study desk. You can adjust brightness, arrange
things, and make it comfortable for your eyes. Similarly, Windows provides Display Settings
to customize your screen.
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What are Display Settings?
Display settings in Microsoft Windows allow users to control how things appear on the
screen.
To open it:
• Right-click on Desktop → Click Display Settings
Main Settings You Can Configure
Let’s understand each setting in a simple way:
1. Brightness and Color
You can control:
• Screen brightness
• Night light (reduces blue light)
Useful for:
• Protecting eyes
• Using computer at night
2. Scale and Layout
This controls:
• Size of text, apps, and icons
Example:
• 100% → Normal size
• 125% → Bigger size
Useful for:
• Better readability
• High-resolution screens
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3. Display Resolution
Resolution means clarity of the screen.
Examples:
• 1920 × 1080 (Full HD)
• 1366 × 768
Higher resolution = sharper image
Diagram for Resolution
Low Resolution High Resolution
------------------ ----------------------
| Blurry Image | | Clear Image |
| Large Pixels | | Small Pixels |
------------------ ----------------------
4. Display Orientation
You can rotate screen:
• Landscape (default)
• Portrait
• Landscape (flipped)
• Portrait (flipped)
Useful for:
• Reading documents
• Coding or designing
5. Multiple Displays
If you connect more than one screen, you can:
• Duplicate screen
• Extend screen
• Use only one display
Useful for:
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• Multitasking
• Presentations
6. Advanced Display Settings
Includes:
• Refresh rate (60Hz, 120Hz etc.)
• Graphics card details
Higher refresh rate = smoother experience
7. Night Light
Reduces blue light and makes screen warm.
Helps:
• Reduce eye strain
• Improve sleep
8. Color Calibration
Adjusts:
• Contrast
• Brightness
• Color balance
Useful for:
• Designers
• Photo/video editing
Why Display Settings Matter?
• Improve comfort
• Enhance productivity
• Protect eyesight
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• Customize experience
Conclusion
Both parts of this question are about making your computer usage smart and efficient.
• In part (a), you learned how to quickly find files using extensions like *.pdf in
Windows search. This saves time and helps in managing data easily.
• In part (b), you explored different display settings that allow you to personalize your
screen for comfort, clarity, and better performance.
If you understand these concepts practically, your daily computer work will become much
easier and faster.
4. (a) Write step by step process to restore deleted les from recycle bin.
(b) What is the signicance of windows display sengs?
Ans: Part (a) Restoring Deleted Files from Recycle Bin
When you delete a file in Windows, it doesn’t vanish immediately. Instead, it goes into the
Recycle Bin, which acts like a safety net. If you change your mind, you can restore the file
easily.
Step-by-Step Process
1. Locate the Recycle Bin
o On your desktop, look for the Recycle Bin icon (a trash can symbol).
o Double-click to open it.
2. Browse Deleted Files
o Inside, you’ll see a list of files and folders you deleted.
o You can sort them by name, date deleted, or original location.
3. Select the File(s)
o Click once on the file you want to restore.
o To select multiple files, hold down the Ctrl key and click each file.
4. Restore the File(s)
o Right-click on the selected file(s).
o Choose Restore from the context menu.
o Alternatively, click the Restore the selected items option at the top.
5. Check the Original Location
o The file(s) will reappear in their original folder before deletion.
o For example, if you deleted a Word document from “Documents,” it will
return there.
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6. Verify
o Open the folder to confirm the file is back and usable.
Diagram: Restoring Files
Delete File → Goes to Recycle Bin → Select File → Click
Restore → Returns to Original Location
Key Points
• Files remain in the Recycle Bin until emptied manually.
• If you Shift + Delete, files bypass the Recycle Bin and cannot be restored this way.
• Restoring is quick and doesn’t require special software.
Part (b) Significance of Windows Display Settings
Windows display settings control how information appears on your screen. They are crucial
for usability, comfort, and productivity.
1. Resolution Settings
• Resolution determines the clarity of text and images.
• Higher resolution = sharper visuals.
• Example: 1920x1080 (Full HD) vs. 3840x2160 (4K).
Significance:
• High resolution improves detail for designers and gamers.
• Lower resolution may be better for older hardware.
2. Orientation
• Controls whether the screen is in landscape or portrait mode.
• Useful for tablets or monitors that rotate.
Significance:
• Portrait mode is great for reading documents or coding.
• Landscape is standard for videos and presentations.
3. Multiple Displays
• Allows connecting more than one monitor.
• Options: Duplicate, Extend, or Show only on one display.
Significance:
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• Extending displays boosts productivity (e.g., one screen for research, another for
writing).
• Presenters can duplicate screens for audiences.
4. Brightness and Color Calibration
• Adjusts brightness, contrast, and color accuracy.
Significance:
• Reduces eye strain.
• Ensures accurate colors for graphic designers and photographers.
5. Scaling and Layout
• Adjusts the size of text, apps, and icons.
• Useful for high-resolution screens where items appear too small.
Significance:
• Improves readability.
• Customizes display for user comfort.
6. Night Light Mode
• Reduces blue light emission by adding a warm tint.
Significance:
• Helps reduce eye strain at night.
• Improves sleep quality by minimizing blue light exposure.
7. Refresh Rate
• Determines how often the screen updates per second (measured in Hz).
• Example: 60Hz vs. 120Hz vs. 240Hz.
Significance:
• Higher refresh rates = smoother visuals.
• Essential for gaming and video editing.
Diagram: Windows Display Settings
Windows Display Settings
---------------------------------
| Resolution | Orientation |
| Multiple Monitors | Brightness |
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| Scaling | Night Light |
| Refresh Rate | Color Settings |
---------------------------------
Why Display Settings Matter
1. User Comfort
o Proper brightness and scaling reduce eye strain.
o Night light improves sleep patterns.
2. Productivity
o Multiple monitors and correct resolution boost efficiency.
o Orientation helps tailor the screen to tasks.
3. Performance
o Refresh rate and resolution affect gaming and video quality.
o Color calibration ensures accuracy in creative work.
4. Accessibility
o Scaling helps users with vision difficulties.
o Custom settings make computers usable for everyone.
Real-Life Example
• A student preparing a presentation uses duplicate display to show slides on a
projector.
• A graphic designer calibrates colors for accurate printing.
• A gamer sets refresh rate to 144Hz for smooth gameplay.
• An office worker uses night light mode to reduce strain during late-night work.
Final Thought
This question highlights two practical aspects of using Windows:
• Restoring files from the Recycle Bin shows how Windows protects users from
accidental deletions.
• Display settings demonstrate how Windows adapts to user needs, balancing
comfort, productivity, and performance.
In short:
• Restoring files is a simple safety net.
• Display settings are powerful tools for customizing your computing experience.
Together, they show how Windows is designed to be user-friendly, secure, and adaptable.
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SECTION-C
5. Explain dierent transmission modes with help of suitable examples.
Ans: When we talk about communication in computer networks, one important concept is
transmission modes. Simply put, transmission modes describe how data flows between
two devices. Imagine two people talking—sometimes one speaks and the other listens,
sometimes both talk at once, and sometimes they take turns. Similarly, computers also
follow different ways of sending and receiving data.
There are three main transmission modes:
1. Simplex Mode
2. Half-Duplex Mode
3. Full-Duplex Mode
1. Simplex Mode (One-Way Communication)
What is Simplex Mode?
In simplex mode, data flows in only one direction. One device always sends data, and the
other only receives it. There is no reverse communication.
Real-Life Example
Think of a radio or TV broadcast:
• The TV station sends signals.
• You receive them.
• But you cannot send anything back to the TV station.
Diagram
Sender ---------> Receiver
(One Direction Only)
Technical Examples
• Keyboard → Computer (keyboard sends input, computer receives)
• TV broadcasting
• Radio transmission
Key Features
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• Only one device can transmit
• No feedback or reply possible
• Simple and low-cost
When is it used?
Simplex mode is used where only one-way communication is required, like broadcasting or
input devices.
2. Half-Duplex Mode (Two-Way, But One at a Time)
What is Half-Duplex Mode?
In half-duplex mode, data can flow in both directions, but not at the same time. Devices
take turns sending and receiving data.
Real-Life Example
Think of a walkie-talkie:
• One person speaks while the other listens.
• Then the other person replies.
• Both cannot speak at the same time.
Diagram
Device A <--------> Device B
(One at a time communication)
Technical Examples
• Walkie-talkies
• Old Ethernet networks (hub-based)
• CB radios
Key Features
• Two-way communication possible
• Only one device transmits at a time
• Slight delay due to turn-taking
When is it used?
Half-duplex is used when communication is needed in both directions, but not
simultaneously.
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3. Full-Duplex Mode (Two-Way Simultaneous Communication)
What is Full-Duplex Mode?
In full-duplex mode, data flows in both directions at the same time. Both devices can send
and receive data simultaneously.
Real-Life Example
Think of a phone call:
• Both people can talk and listen at the same time.
• No need to wait for the other person to finish.
Diagram
Device A <=======> Device B
(Simultaneous communication)
Technical Examples
• Mobile phones
• Modern Ethernet networks
• Video conferencing
Key Features
• Fast communication
• No waiting time
• Efficient and smooth data exchange
When is it used?
Full-duplex is used where real-time communication is important, like video calls or online
meetings.
Comparison of Transmission Modes
Feature
Simplex
Half-Duplex
Full-Duplex
Direction
One-way
Two-way (one at a
time)
Two-way
(simultaneous)
Speed
Fast (one
direction)
Medium
Fastest
Communication
No feedback
Delayed feedback
Instant feedback
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Example
TV, Keyboard
Walkie-talkie
Phone, Internet
Easy Way to Remember
• Simplex → “Only Send”
• Half-Duplex → “Send or Receive (Turn by Turn)”
• Full-Duplex → “Send & Receive Together”
Conclusion
Transmission modes are the backbone of communication in computer networks. They
define how efficiently and effectively data travels between devices.
• Simplex mode is best for one-way communication like broadcasting.
• Half-duplex mode allows two-way communication but requires devices to take
turns.
• Full-duplex mode provides the most advanced communication, allowing
simultaneous data exchange, making it the most efficient and widely used today.
Understanding these modes helps us see how everyday technologies like phones, the
internet, and even keyboards work behind the scenes. Once you relate them to real-life
situations, the concept becomes very easy and interesting to understand.
6. What is mulplexing? Explain its dierent types.
Ans: What is Multiplexing?
Multiplexing is a technique used in communication systems to combine multiple signals
into one medium for transmission. Instead of sending each signal separately (which would
require multiple wires or channels), multiplexing allows several signals to share the same
channel.
Think of it like a highway: instead of building separate roads for each car, you allow multiple
cars to travel on the same road, but in different lanes or at different times.
Key Idea
• Sender side: Signals are combined using a multiplexer.
• Receiver side: Signals are separated using a demultiplexer.
Diagram: Multiplexing Concept
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Multiple Input Signals → Multiplexer → Single Channel →
Demultiplexer → Multiple Output Signals
Types of Multiplexing
There are several types of multiplexing, each using a different strategy to share the channel.
1. Frequency Division Multiplexing (FDM)
• Each signal is assigned a different frequency band within the channel.
• Signals are transmitted simultaneously, but separated by frequency.
Example: Radio broadcasting. Different stations (FM 91.1, FM 93.5, FM 98.3) transmit at
different frequencies, and you tune your radio to the desired frequency.
Significance: Efficient for analog signals, widely used in radio, TV, and cable systems.
2. Time Division Multiplexing (TDM)
• Each signal is assigned a time slot in a repeating cycle.
• Signals take turns using the channel, one after another.
Example: Digital telephony. Multiple phone calls share the same line, each getting a time
slot.
Significance: Efficient for digital signals, ensures fair sharing of bandwidth.
3. Wavelength Division Multiplexing (WDM)
• Used in optical fiber communication.
• Each signal is assigned a different wavelength (color of light).
• Signals travel simultaneously through the same fiber.
Example: Internet backbone networks use WDM to transmit huge amounts of data across
continents.
Significance: Provides extremely high capacity, essential for modern internet.
4. Code Division Multiplexing (CDM) / CDMA
• Each signal is assigned a unique code.
• All signals share the same frequency band and time, but codes separate them.
Example: Mobile communication (CDMA technology). Multiple users can talk
simultaneously without interfering.
Significance: Highly secure and efficient, supports many users in wireless systems.
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5. Space Division Multiplexing (SDM)
• Signals are separated by physical space.
• Each signal travels through a separate physical path (like multiple antennas or
fibers).
Example: MIMO (Multiple Input Multiple Output) technology in 4G/5G networks uses
multiple antennas to transmit parallel signals.
Significance: Boosts capacity and reliability in wireless communication.
Diagram: Types of Multiplexing
FDM → Different Frequencies
TDM → Different Time Slots
WDM → Different Wavelengths (light colors)
CDM → Different Codes
SDM → Different Physical Paths
Everyday Analogies
• FDM: Like different radio stations broadcasting at different frequencies.
• TDM: Like students taking turns to speak in class.
• WDM: Like different colors of light passing through the same glass fiber.
• CDM: Like people speaking different languages in the same room—each listener
understands only their language.
• SDM: Like multiple parallel roads carrying traffic in the same direction.
Advantages of Multiplexing
1. Efficient use of resources.
2. Reduces cost (one channel instead of many).
3. Increases capacity of communication systems.
4. Enables simultaneous transmission of multiple signals.
Real-Life Applications
• Television broadcasting (FDM).
• Telephone networks (TDM).
• Fiber-optic internet (WDM).
• Mobile communication (CDM).
• Wireless broadband (Wi-Fi, 4G/5G) (SDM + TDM).
Final Thought
Multiplexing is the art of sharing. It allows multiple signals—whether voices, data, or
video—to travel together efficiently over the same medium. Each type (FDM, TDM, WDM,
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CDM, SDM) uses a different strategy—frequency, time, wavelength, code, or space—but the
goal is the same: maximize efficiency and capacity.
SECTION-D
7. How one can secure his system from various network security 10 threats?
Ans: In today’s digital world, our computers and smartphones are like our personal homes.
Just as we lock our doors to protect our belongings, we must also protect our systems from
network security threats. These threats include hackers, viruses, malware, phishing attacks,
and many other dangers that try to steal or damage our data.
Imagine Your System as a House
Think of your computer as a house connected to a big city (the internet). Many people
(users) are good, but some are thieves (hackers). If your house is not protected, anyone can
enter and harm you.
So, what do we do?
We use locks, cameras, alarms—and similarly, we use security tools for our system.
Major Network Security Threats
Before learning protection, we should know what we are protecting against:
• Viruses & Malware – Harmful programs that damage your system
• Phishing Attacks – Fake emails or messages that trick you
• Ransomware – Locks your data and demands money
• Spyware – Secretly collects your personal information
• Password Attacks – Hackers try to guess your passwords
• Man-in-the-Middle Attacks – Someone secretly intercepts your communication
• Denial of Service (DoS) – Overloads your system so it stops working
How to Secure Your System (Step-by-Step)
Let’s now understand how you can protect your system in a simple and practical way:
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1. Use Strong Passwords
Your password is like the main lock of your house.
• Use a mix of letters, numbers, and symbols
• Avoid simple passwords like 12345 or password
• Example: E@sySiksha#2026
Also, use different passwords for different accounts.
2. Install Antivirus Software
Antivirus acts like a security guard.
• It detects and removes viruses and malware
• Always keep it updated
• Examples: Quick Heal, Norton, Avast
3. Keep Your System Updated
Software updates are like repairing weak doors or windows.
• Update your Operating System regularly
• Updates fix bugs and security holes
4. Use a Firewall
A firewall works like a gatekeeper.
• It controls incoming and outgoing traffic
• Blocks suspicious connections
Most systems already have built-in firewalls—just make sure they are ON
5. Be Careful with Emails & Links
Many attacks come through fake emails.
• Don’t click on unknown links
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• Don’t download attachments from strangers
• Check sender details carefully
If something looks suspicious, it probably is!
6. Use Secure Networks
Public Wi-Fi is like an open door—anyone can enter.
• Avoid using public Wi-Fi for banking or important work
• Use VPN (Virtual Private Network) for extra security
7. Backup Your Data
Always keep a copy of your important data.
• Use cloud storage or external drives
• Helps you recover data if attacked by ransomware
8. Enable Two-Factor Authentication (2FA)
This adds an extra layer of security.
• Even if someone knows your password, they need a second code
• Example: OTP sent to your phone
9. Limit Software Downloads
Only download software from trusted sources.
• Avoid pirated or cracked software
• These often contain hidden malware
10. Educate Yourself & Stay Alert
The best protection is awareness.
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• Learn about new threats
• Stay updated with cybersecurity tips
• Always think before clicking anything online
Simple Diagram to Understand Security Layers
+----------------------+
| Internet |
+----------+-----------+
|
[ Firewall ]
|
+----------+-----------+
| Antivirus |
+----------+-----------+
|
+----------+-----------+
| Operating System |
+----------+-----------+
|
+----------+-----------+
| User (You) |
+----------------------+
This diagram shows that security works in layers. If one layer fails, others still protect
your system.
Conclusion
Securing your system is not a difficult task—it just requires awareness and good habits. Just
like we take care of our home with locks and security systems, we must also protect our
digital space.
By using strong passwords, installing antivirus software, avoiding suspicious links, and
staying alert, you can easily protect your system from most network threats.
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8. (a) What is a rewall? Explain various benets associated 5 with it.
(b) Write a short note on spoong.
Ans: Part (a) Firewall and Its Benefits
What is a Firewall?
A firewall is a security system—either hardware, software, or a combination of both—that
monitors and controls incoming and outgoing network traffic. It acts like a gatekeeper
between your computer/network and the outside world (the internet).
Think of it as a security guard at the entrance of a building. The guard checks everyone who
tries to enter or leave, allowing only trusted people and blocking suspicious ones. Similarly,
a firewall filters data packets, allowing safe traffic and blocking harmful or unauthorized
access.
How Firewalls Work
• Firewalls use rules to decide whether to allow or block traffic.
• They inspect data packets based on IP addresses, ports, and protocols.
• They can block malicious websites, prevent hackers from accessing your system, and
stop unauthorized applications from sending data out.
Benefits of Firewalls
1. Protection Against Unauthorized Access
Firewalls prevent hackers or malicious software from entering your system. They act as the
first line of defense.
Example: If a hacker tries to access your computer remotely, the firewall blocks the
attempt.
2. Monitoring Network Traffic
Firewalls continuously monitor data entering and leaving your network. Suspicious activity is
flagged or blocked.
Example: If an unknown program tries to send your personal data to an external server, the
firewall stops it.
3. Preventing Malware and Viruses
Firewalls can block harmful websites or downloads that may contain malware, reducing the
risk of infection.
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4. Enhanced Privacy
By controlling outgoing traffic, firewalls prevent unauthorized applications from leaking
sensitive information.
5. Customizable Security
Users or administrators can set specific rules—like blocking social media sites in offices or
restricting access to certain ports.
Diagram: Firewall Concept
Internet → Firewall → Secure Internal Network
(Blocks harmful traffic, allows safe traffic)
Part (b) Spoofing
What is Spoofing?
Spoofing is a cyberattack technique where a malicious actor pretends to be someone else to
gain unauthorized access or trick users. It’s like wearing a disguise to fool people into
believing you are trustworthy.
Types of Spoofing
1. IP Spoofing
o Attackers forge the source IP address in data packets to appear as if they are
coming from a trusted source.
o Used to bypass security systems or launch denial-of-service attacks.
2. Email Spoofing
o Attackers send emails that look like they come from legitimate sources (like
banks or colleagues).
o Often used in phishing attacks to steal sensitive information.
Example: You receive an email that looks like it’s from your bank, asking for login details. In
reality, it’s from a hacker.
3. Caller ID Spoofing
o Attackers manipulate phone numbers to make calls appear as if they’re from
trusted sources.
o Common in scam calls.
4. Website Spoofing
o Fake websites mimic real ones to trick users into entering personal
information.
o Example: A fake PayPal site designed to steal login credentials.
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Why Spoofing is Dangerous
• It undermines trust in communication systems.
• Leads to identity theft, financial loss, and data breaches.
• Difficult to detect because attackers mimic trusted sources convincingly.
Preventing Spoofing
• Use firewalls and intrusion detection systems.
• Verify email authenticity (check sender address carefully).
• Use encryption and secure protocols.
• Educate users about phishing and scams.
Linking Firewall and Spoofing
Notice how these two concepts connect:
• Firewalls act as a defense mechanism, filtering suspicious traffic.
• Spoofing is a technique attackers use to bypass defenses by pretending to be
legitimate.
Together, they highlight the ongoing battle between cybersecurity tools and cybercriminals.
Real-Life Example
• A company receives spoofed emails appearing to be from its CEO, asking employees
to transfer money.
• The firewall blocks suspicious attachments, but employees must still recognize the
spoofing attempt.
• This shows that technology plus awareness is essential for security.
Final Thought
This question highlights two key aspects of cybersecurity:
• Firewalls are protective barriers that monitor and control traffic, offering benefits
like protection, monitoring, privacy, and customization.
• Spoofing is a deceptive attack method where hackers disguise themselves as trusted
sources to steal information or gain access.
“This paper has been carefully prepared for educaonal purposes. If you noce any
mistakes or have suggesons, feel free to share your feedback.”
