Chapter 9: Networking and Open Source Concepts Class 12 Computer Science NCERT Solutions

Class 12 Computer Science (Python) – Chapter 9: Networking and Open Source Concepts

Question 1: Identify the Domain Name and URL from the following:
http://www.income.in/home.aboutus.html

Domain Name: income.in
URL: http://www.income.in/home.aboutus.html

Question 2: What is web hosting?

Answer:
Web hosting is a service that provides storage space and access for websites on the Internet. It allows websites to be accessible to users worldwide by storing the site’s files on a server connected to the web.

Question 3: Write two characteristics of Wi-Fi.

Answer:

• It enables wireless connectivity without physical cables.
• It is suitable for short-range communication, typically within a building or room.

Question 4: Which protocol is used to create a connection with a remote machine?

Answer:
Telnet is the protocol used to connect to a remote machine. It allows users to log into another computer over a network and operate it as if it were local.

Question 5: Which protocol is used to create a connection to a remote machine? Give any two advantages of using optical fibers.

Protocol: Telnet

Advantages of Optical Fibers:

• They support extremely high-speed data transfer.
• They are immune to electromagnetic interference.
• They have very low signal attenuation.

Question 6: Expand the following abbreviations

Question 7: What is the difference between packet switching and message switching?

Question 8: What is cloud computing?

Answer:
Cloud computing refers to the delivery of computing services—including servers, storage, databases, networking, software, and analytics—over the Internet (“the cloud”) to offer flexible resources, faster innovation, and economies of scale.

Question 9: Which type of network (out of LAN, PAN, and MAN) is formed when you connect two mobiles using Bluetooth to transfer a video?

Answer:
PAN (Personal Area Network)

Question 10: Write one characteristic each for 2G and 3G mobile technologies.

Answer:
2G: Primarily supports voice communication.
3G: Supports high-speed data transfer in addition to voice services.

Question 11: What is the difference between packet switching and circuit switching techniques?

Question 12: Write two advantages of using an optical fibre cable over an Ethernet cable to connect two service stations that are 200 meters apart.

• Optical fibres offer much faster data transfer speeds.
• They experience lower signal loss over long distances compared to Ethernet cables.

Question 13: Write one advantage of bus topology of network. Also illustrate how four (4) computers can be connected with each other using bus topology.

Answer:
An advantage of bus topology is that it uses the least amount of cable compared to other topologies, making it cost-effective.

Computer A ─┬───────────────┬─ Computer B
            │               │
          Backbone       Backbone
            │               │
Computer C ─┴───────────────┴─ Computer D

Question 14: Give one suitable example of each: URL and Domain Name.

URL: http://waltons.in
Domain Name: gmail.com

Question 15: Write one advantage of star topology network. Also illustrate how five (5) computers can be connected using star topology.

Answer:
An advantage of star topology is that it is easy to install or remove devices without affecting the rest of the network.

               Computer A
                   |
                   |
Computer B —— Hub —— Computer C
                   |
                   |
             Computer D
                   |
                   |
             Computer E

Question 16: What is the function of a Modem?

Answer:
A modem (Modulator-Demodulator) converts digital signals from a computer into analog signals for transmission over telephone lines (modulation) and converts incoming analog signals back into digital form (demodulation).

Question 17: Explain the purpose of a router.

Answer:
A router is a device that connects multiple networks together and directs data packets between them. It determines the best path for data to travel using a routing table and supports different networking protocols.

Question 18: Name any two components required for networking.

• Repeater
• Router

Question 19: What are repeaters?

Answer:
A repeater is a network device that receives a signal, amplifies or regenerates it, and retransmits it. This helps the signal travel longer distances without losing quality.

Question 20: Mention one advantage of star topology over bus topology.

Answer:
In a star topology, it is easy to add or remove computers without affecting the rest of the network, which is not the case in a bus topology.

Question 21: Differentiate between packet switching and message switching.

Question 22: Differentiate between Bus and Star topology.

Question 23: What is VoIP?

Answer: VoIP (Voice over Internet Protocol) allows users to make voice calls using an internet connection instead of a regular telephone line. It converts voice into digital packets and sends them over the internet.

Question 24: In networking, what is WAN? How is it different from LAN?

Question 25: Define the term bandwidth. Give any one unit of bandwidth.

Answer: Bandwidth refers to the amount of data that can be transferred over a network in a specific amount of time.
Unit: bps (bits per second)

Question 26: What is the difference between LAN and MAN?

Question 27: What is the importance of URL in networking?

Answer: A URL (Uniform Resource Locator) specifies the address of a web resource on the internet. It helps locate and access files, webpages, or services using web browsers.

Question 28: What was the role of ARPANET in the computer network?

Answer: ARPANET (Advanced Research Projects Agency Network) was the first operational packet-switching network developed in 1969 by the US government for defense purposes. It laid the foundation for the modern internet.

Question 29: Which of the following is not a unit for data transfer rate?

(i) bps
(ii) abps
(iii) gbps
(iv) kbps
Answer: (ii) abps is not a valid unit for data transfer rate.

Question 30: Identify the type of topology from the following:

Question 31: ABC International School is planning to connect all computers, each spread over a distance of 50 metres. Suggest an economic cable type having high speed data transfer to connect these computers.

Answer: Optical fibre cable.

Question 32: Mahesh wants to transfer data within a city at very high speed. Write the wired transmission medium and type of network.

Wired transmission medium: Optical fibre cable
Type of network: MAN (Metropolitan Area Network)

Question 33: Which device is used to connect all computers inside a lab?

Answer: A Hub is used to connect all the computers in a lab. It acts as a central device that allows multiple computers to communicate with each other within a local area network (LAN).

Question 34: Which device is used to connect all computers to the internet using telephone wire?

Answer: Modem
A modem is the device used to connect computers to the Internet via telephone lines. It modulates and demodulates digital data into analog signals and vice versa for transmission over telephone networks.

Question 35: What is a Wi-Fi Card?

Answer: A Wi-Fi card is a hardware device installed in a computer or laptop that enables it to connect to wireless networks. It uses radio waves to receive and transmit data, allowing the device to access the Internet or other network resources without physical cables.

Short Answer Type Questions

Question 1: Write any two differences between twisted pair and coaxial pair cable.

Answer:

Question 2: Write one advantage of Bus Topology of network. Also, illustrate how 4 computers can be connected with each other using Star Topology.

Answer:

Advantage of Bus Topology: It requires the least amount of cable compared to other topologies, making it cost-effective for small networks.

Star Topology Illustration:

              [Computer A]
                   |
              [ Switch/Hub ]
             /       |       \
 [Computer B]  [Computer C]  [Computer D]

Question 3: Explain any two switching techniques used in networking.

Answer:

• Message Switching: In this method, entire messages are transferred from one node to another and stored temporarily at intermediate nodes before being forwarded. It is similar to how letters are delivered through a post office.
• Packet Switching: Here, messages are broken into smaller data units called packets. These packets are sent independently across the network and reassembled at the destination, allowing efficient use of bandwidth and better fault tolerance.

Long Answer Type Questions

Question 1: Network Configuration Solutions

(a) Differentiate between PAN and LAN types of networks:

(b) Which protocol helps us to transfer files to and from a remote computer?

• FTP (File Transfer Protocol)
• Telnet
• TCP (Transmission Control Protocol)

(c) Write two advantages of 3G over 2G mobile telecommunication technologies in terms of speed and services:

• Speed: Faster web browsing and file transfer
• Services: Better video clarity and improved security

(d) Write two characteristics of Web 2.0:

• Makes web more interactive through online social media
• Supports easy online information exchange and video sharing

(e) Write the basic difference between worm and Trojan Horse:

(f) Categorize the following under client-side and server-side scripts:

(g) Intelligent Hub India Network Configuration:

• i) Server Placement Suggestion: The server should be placed at YTOWN, as it has the maximum number of computers and is closest to all other locations.
• ii) Wired Medium: The most suitable wired medium would be Optical Fiber, as it offers high-speed data transfer and is ideal for long-distance communication.
• iii) Hardware Device for Connectivity: A Switch or Hub should be installed to connect all the computers within each location.
• iv) Server/Protocol for Live Interaction: Video Conferencing or VoIP protocols would be most helpful for live interaction between experts at the Head Office and people at YHUB locations.

Question 2: Indian School Network Configuration

i) Cable Layout Suggestion:

The cable layout should be a star topology, where the central hub connects all the buildings (Senior, Junior, Admin, Hostel) efficiently.

ii) Server Placement:

The server should be placed in the ADMIN building, as it has the maximum number of computers.

iii) Device Placement:

iv) Suitable Transmission Media for Interconnecting the School and Inquiry Office:

• Fiber Optic Cable
• Microwave
• Radiowave

Question 3: Vidya Senior Secondary Public School Network Configuration

i) Suitable Topology:

A star topology would be the most suitable as it provides efficient communication between all the wings.

ii) Server Placement:

The server should be placed in the SENIOR wing, as it has the maximum number of computers.

iii) Device Placement:

Hub/Switch should be placed in all wings to connect multiple computers.

iv) Communication Medium:

Radiowaves would be the best option as they are reliable and can travel through obstacles like hills.

Question 5: Network Classification and Protocols

i) Suitable Network for Connecting Two Adjacent Computer Labs:

LAN (Local Area Network) should be used as it is ideal for networks covering short distances.

ii) Difference Between HTTP and FTP:

iii) Major Difference Between Message Switching and Packet Switching:

• Message Switching: Entire message is sent in one go.
• Packet Switching: The message is divided into packets for efficient transmission.

iv) Basic Difference Between DNS and URL:

• DNS (Domain Name System): Resolves domain names to IP addresses.
• URL (Uniform Resource Locator): Specifies the address of a web resource.

v) Application of Web 2.0:

• Web Hosting
• Web Browsing

vi) Categorizing Scripts:

Question 6: Trine Tech Corporation (TTC)

i) Suggested Server Block:

Finance Block, because it has the maximum number of computers.

ii) Block to Cable Layout:

• Finance
• HR
• Accounts
• R&D

iii) Connectivity Between Bangalore and London:

Best Connectivity: Satellite link

iv) Suggested Networking Device:

Suggested Device: Switch

Question 7: G.R.K International Inc.

Suggested Server Block:

Human Resources, because it has the maximum number of computers.

Cable Layout Among the Blocks:

• HR
• Finance
• Tech
• Admin

Networking Device for Each Block:

Suggested Networking Device: Switch

Media for Connectivity Between Bengaluru and Delhi:

Suggested Media: Satellite link

Question 8: Rovenza Communications International (RCI)

Suggested Server Block:

Faculty Recording Block

Cable Layout Among the Blocks:

• Faculty
• IT
• Admin

Network Type:

LAN (Local Area Network)

Wireless Channel for Global Connection:

Satellite

Advantages of Open Source Software:

• Source code is available, can be modified, copied & distributed
• Free to use, unlike proprietary software which is paid and restricted

Cybercrime Definition:

Crime that involves computers and networks.
Crime that does not fall under Cybercrime: Stealing keyboard and mouse from a shop.

Question 9: Networking Topology & Other Concepts

Identify the Type of Topology:

• Star Topology: Each node is directly connected to the server. Requires more cable and increases installation cost.
• Bus Topology: All nodes share a single common data path (backbone).

Expansion of Acronyms:

Who is a Hacker?

A hacker is a computer enthusiast who uses programming skills to intentionally access a computer system without authorization, usually not for malicious reasons.

IP Address:

A 32-bit binary number represented as four decimal values (e.g., 140.179.220.200). It uniquely identifies devices on a network.

Type of Network for Data Sharing:

MAN (Metropolitan Area Network)

Rehaana Medicos Center Network Setup:

• Suggested Server Block: Research Lab (maximum computers)
• Repeater: Between Accounts and Store to boost signal over long distance
• Hub/Switch: In the server room to manage data traffic

System to Prevent Unauthorized Access:

Suggested System: Firewall

Question 10: Domain Name vs. IP Address

Domain Name:

An alphanumeric address used to identify a resource over the network (e.g., www.Gabsclasses.com).

IP Address:

A numeric address assigned to a device or resource in a network (e.g., 102.112.0.153).

Advantages of Optical Fibre over Ethernet Cable:

• Faster communication speed
• Immune to electrical and noise interference

EPG Campus Setup:

• Suggested Server Building: Faculty Studio Building
• Suggested Network Type: LAN
• Suggested Wireless Channel: Satellite

Question 11: Telemedicine Network Setup

Link Type for Network Setup:

Suggested Link: Radio Link

Network Type for Telemedicine:

Network Type: MAN (Metropolitan Area Network)

Consultation Method:

Consultation Method: Email

Protocol for Receiving Emails:

Protocol: POP3

What are Cookies?

Cookies are small files that store user information and help identify users when they log into a system.

Script Type for Client Side Validation:

Script Type: Server-side script

Freeware vs Free Software:

Difference: Freeware is available for unlimited use at no cost, while free software may only be free for a limited time or under conditions.

Question 12: Workalot Consultants – Network Setup

Server Placement:

The most suitable place to install the server is building “RED” because it has the maximum number of computers, minimizing communication delays.

Cable Layout:

Due to long distances between buildings GREEN, BLUE, and RED, a repeater should be used along the cabling route to prevent signal loss.

Switch Placement:

A switch is needed in all buildings to interconnect computers within each building.

High-Speed Link to Mumbai:

The most suitable cable for connecting to the head office in Mumbai is Optical Fiber.

Question 13: Granuda Consultants – Network Setup

Server Placement:

The server should be installed in building “JAMUNA” as it houses the most computers, reducing delays.

Cable Layout:

Bus Topology is recommended for connecting the buildings.

Repeater Placement:

A repeater should be placed between buildings GANGA and JAMUNA to avoid signal degradation.

Switch Placement:

A switch should be installed in each building.

High-Speed Link to Kolkata:

Optical Fiber is the best medium to connect to the head office in Kolkata.

Question 14: India Skills Hub – Network Setup

Server Location:

The server should be placed at UVW-TOWN as it is centrally located and equidistant from the villages P, Q, and R.

Cable Layout:

• Optical Fiber should be used to connect UVW-TOWN with the head office.
• Co-axial cable should be used for connections between UVW-TOWN and villages P, Q, and R.

Device Placement:

• Hubs should be used in villages P, Q, and R.
• Bus topology is recommended for connecting to the head office.

Protocol for Live Interaction:

• HTTP for live interaction
• Other protocols: UDP, FTP

Question 15: Mudra Publishing – Shimla Network Setup

Network Topology:

Bus Topology is most suitable due to the central backbone design.

Server Placement:

BLOCK-D is best for server installation because it contains the most computers.

Device Placement:

• Switches should be placed in each block to manage local communication.
• Repeater should be placed between BLOCK-D and BLOCK-C due to long distance.

High-Speed Connectivity to Delhi:

The most economical option is Radiowave Transmission because it is cost-effective, supports long distances, and easily penetrates buildings.

Very Short Answer Type Questions

Question 1: Define firewall.

A firewall is a security system designed to monitor and control incoming and outgoing network traffic. It serves to prevent unauthorized access to or from a private network. Firewalls can be implemented as hardware, software, or a combination of both.

Question 2: Write any two examples of Server-side Scripts.

• ASP (Active Server Pages)
• PHP (Hypertext Preprocessor)

Question 3: What is the difference between E-mail & Chat?

Email is asynchronous communication, meaning messages are sent and read at different times.
Chat, on the other hand, is typically real-time communication, where both parties are online at the same time.

Question 4: Write names of any two popular open source software, which are used as operating systems.

• Linux
• Unix

Question 5: What is the difference between video conferencing and chat?

In video conferencing, multiple participants can interact using text, video, and audio. It allows group communication. In contrast, chat is generally a one-to-one communication tool and typically involves only text-based interaction.

Question 6: Expand the following abbreviations:

• HTTP: Hyper Text Transfer Protocol
• VOIP: Voice Over Internet Protocol

Question 7: What is the difference between HTTP and FTP?

HTTP (HyperText Transfer Protocol) is used for transferring web pages and multimedia content over the internet.
FTP (File Transfer Protocol) is used for transferring files over the internet.

Question 8: What out of the following will you use to have an audio-visual chat with an expert sitting in a far-away place to fix-up a technical issue?

• VoIP
• Email
• FTP

Answer: VoIP (Voice over Internet Protocol) is the most suitable for audio-visual communication.

Question 9: Name one server-side scripting language and one client-side scripting language.

• Client-side: JavaScript, VBScript
• Server-side: ASP, JSP

Question 10: Which out of the following comes under cyber crime?

• Operating someone’s internet banking account without his knowledge.
• Stealing a keyboard from someone’s computer.
• Working on someone’s computer with his/her permission.

Answer: Operating someone’s internet banking account without his knowledge.

Question 11: Name two proprietary software along with their application.

• MS Office: A suite of applications like MS Word, MS Excel, MS PowerPoint.
• Visual Studio: An integrated development environment for application development in languages like Visual Basic, C++, etc.

Question 12: Out of the following, identify client-side scripts and server-side scripts:

• Server-side scripts: ASP, JSP
• Client-side scripts: JavaScript, VBScript

Question 13: Compare open-source software and proprietary software.

Question 14: Differentiate between XML and HTML.

XML (Extensible Markup Language) is used to store and transport data with a focus on the structure and meaning of the data.
HTML (Hypertext Markup Language) is used to display data on web pages, with a focus on presentation.

Question 15: What is WEB 2.0?

Web 2.0 refers to the second generation of web-based services and applications that focus on collaboration, sharing, and user-generated content. It includes social media platforms, blogs, wikis, and other interactive web technologies.

Question 16: Which of the following is/are not a client-side script?

• VB Script
• Java Script
• ASP
• PHP

Answer: ASP and PHP are server-side scripts.

Question 17: If someone has hacked your website, to whom you lodge the complaint?

The complaint should be lodged with the police under the IT Act, which governs cybercrimes in India.

Question 18: What do you mean by IP address? How is it useful in computer security?

An IP address is a unique numerical identifier assigned to each device on a network. It is essential for routing data between devices on the internet and plays a crucial role in security by identifying and tracking the location of systems in the network.

Question 19: What do you mean by spam mails? How can you protect your mailbox from spams?

Spam mails are unsolicited and often irrelevant emails sent in bulk to numerous recipients. You can protect your mailbox by setting up spam filters or using third-party anti-spam tools.

Question 20: When do you prefer XML over HTML and why?

XML is preferred over HTML when you need a flexible data structure that can be customized with your own tags. Unlike HTML, which has predefined tags, XML allows users to define tags suited to their specific needs, providing more flexibility in data representation.

Question 21: How does a firewall protect our network?

A firewall is a security device designed to monitor and control incoming and outgoing network traffic. It functions based on predefined rules to either allow or block traffic. The firewall can be hardware, software, or a combination of both. By controlling traffic between different security zones, it prevents unauthorized access while permitting authorized communication.

How a firewall works:

Question 22: Compare freeware and shareware.

Freeware is software that is made available to users at no cost, but it is still proprietary. The author retains certain rights to the software, such as restricting copying or making modifications.
Shareware is a type of software that is offered for free for a limited time or with limited functionality. To access the full version of the software, users must purchase a license.

Question 23: How are Trojan horses different from worms? Mention any one difference.

A Trojan horse is malware that appears to perform a useful function but actually facilitates unauthorized access to the user’s computer. It does not self-replicate.
A worm is a self-replicating program that spreads across networks without user intervention, often causing harm by using resources and spreading itself.

Question 24: Give the full form of:

• FOSS: Free Open Source Software
• HTTP: Hyper Text Transfer Protocol

Question 25: What is the difference between a Trojan horse and a virus in terms of computers?

A Trojan horse is a non-self-replicating malware that appears to perform a desirable function but instead facilitates unauthorized access.
A computer virus, on the other hand, is a self-replicating program that spreads from one system to another and can cause damage to files and systems.

Question 26: Which term is used for a software/hardware device that is used to block unauthorized access while permitting authorized communications?

Answer: Firewall

Question 27: Write the full forms of the following:

• GNU: GNU’s Not Unix
• XML: Extensible Markup Language

Question 28: Expand the following terminologies:

• GSM: Global System for Mobile Communication
• WLL: Wireless Local Loop

Question 29: Name some cyber offences under the IT Act.

• Tampering with computer source documents
• Hacking
• Publishing obscene information in electronic form

Question 30: What are the three ways of protecting intellectual property?

• Patents
• Copyrights
• Trademarks

Question 31: When a user browses a website, the web server sends a text file to the web browser. What is the name of this?

Answer: The text file is called a Cookie.

Short Answer Type Questions

Question 1: Define the following

Illustration: How VoIP Works

[Microphone] → [VoIP Software] → [Internet] → [Receiver’s VoIP App] → [Speaker]

Question 2: Give the full form of the following terms

Question 3: Differentiate between WORM and VIRUS

Question 4: Expand the following

Question 5: Expand the following abbreviations

Question 6: Give the full form of

Question 7: Write the full forms of the following

Question 8: Expand the following terminologies

Question 9: Give the full forms of the following terms

Question 10: Expand the following abbreviations