CLASS - XI, UNIT-2 NETWORKING AND INTERNET, I,T-SKILLS-802

 

UNIT-2

NETWORKING AND INTERNET

Important Q/ ANS   Strictly as per the CBSE syllabus for class-Xi     INFORMATION TECHNOLOGY-802

Q1. Give the full form of following terms:

1.      ARPANET: Advanced Research Projects Agency Network

2.      LAN: Local area network

3.      MAN: Metropolitan area network

4.      WAN: Wide-area network

5.      WWW: World Wide Web

6.      TELNET: Teletype Network.

7.      PSTN: Public Switched Telephone Network

8.      TCP/IP: Transmission Control Protocol/Internet Protocol

9.      IETF: Internet Engineering Task Force

10    ICANN: Internet Corporation for Assigned Names and Numbers     

11     NIC: Network Interface Card  

       

Q2: What is communication?

Communication is the process of sharing information, ideas, thoughts, and feelings between two or more people. It is a two-way process, involving a sender and a receiver.

Q3: What are the elements of communication?

The key elements of communication:

1. Sender: The person who initiates the communication process.
2. Receiver: The person who receives the communication message.
3. Message: The information that is being shared.
4. Channel: The medium through which the message is sent.
5. Feedback: The response from the receiver to the message.

Q4: What are the three modes to transmit data in a communication network?

Three modes of transmission are simplex, half-duplex, and full-duplex.

In simplex mode, information can be transferred only in one direction. This mode is termed unidirectional. E.g.: Radio, satellites are simple in nature.

In Half-duplex mode is a bidirectional communication between the two nodes, however, only one node at a time can transmit the data. E.g.: Walkie-Talkie.

In full-duplex mode both communicating parties can send and receive at the same time. E.g. Voice Call, Video call

Q5: What is computer network?

A collection of interconnected nodes which communicate by means of some channel form a computer network.

Q6: What are the uses of computer network?

1.                   1.  Resource sharing: Computer networks allow users to share resources such as printers,         scanners,  and software

2. Improved communication: Computer networks can help to improve communication between people and organisations. Through email, video conferencing, and other collaboration tools.
3. Increased productivity: Computer networks can help to increase productivity by allowing users to access information and resources more quickly and easily.
4. Reduced costs: Computer networks can help to reduce costs by eliminating the need for duplicate resources.
5. Global reach: Computer networks can provide global reach, allowing users to connect with people and resources all over the world.
6. Data Backup: Computer networks can be used to back up data and applications.

 

Q7: Define Transmission medium and its types?

A transmission medium/ communication channel is a physical path or substance that allows signals to be transmitted from one point to another.

Guided Medium: It means physical conductors such as twisted pairs, coaxial cable, and fibre optics.

Unguided Medium: It uses electro-magnetic waves that do not require a physical conductor

Guided Medium

1.         Twisted pair cables: These are the most common type of guided transmission media. They are made up of two insulated copper wires twisted together.

2.      Coaxial cables: These cables consist of a central copper core surrounded by a layer of insulation, which is then wrapped in a metal shield.

3.         Fibre optic cables: These cables consist of a core of glass or plastic surrounded by a cladding layer. The core and cladding have different refractive indices, which allows light to be guided along the cable.

Unguided Medium

1.      Radio waves: These waves are used for long-distance communication. They can travel through the air, water, and even through solid objects.

2.      Microwaves: These waves are used for short-range communication. They can travel through the air, but they are blocked by solid objects.

3.      Infrared waves: It’s a type of electromagnetic radiation that has wavelengths longer than visible light but shorter than radio waves. They are invisible to the human eye, but they can be felt as heat. E.g. Remote controls use infrared waves to send signals to devices such as TVs and stereos.

Q7: Define Network Devices?

A network device is a physical or software component that enables computers, printers, and other devices to connect to a network and communicate with each other. They are responsible for routing data packets, managing traffic, and providing security.

E.g. Repeater, hub, router, bridge, switch and gateway

Q8: What is the purpose of network devices? Explain following network devices.

 Repeater, Hub, Router, Bridge, Switch and Gateway

Repeater:

1.      A repeater is used to restore the input signal to its original form, so that it can travel a larger distance.

2.      A repeater is an electronic device that receives a signal and retransmits it.

3.      It is used to extend the range of a signal by amplifying it.

4.      A repeater is used to restore the input signal to its original form, so that it can travel a larger distance.

5.      It is also known as digital generator

 

  Hub:

1.      A hub is a network device that connects multiple devices together on a single network segment.

2.      A hub comprises several input/output (I/O) ports

3.      Data arriving on an incoming line is output to all lines except the line on which the hub receives the data.

 

 

 Switch:

1.      Switches are a more intelligent and efficient way to connect multiple devices together than hubs.

2.      Unlike bridges, which connect two or more LAN segments, switches, are used to connect individual nodes in the network with each other.

3.      They are also more secure.

 

 

Router:

1.      Determines the best route for the data packets to travel to their destination

2.      Routers also provide security features

3.      A router transmits data from incoming network to another network.

4.      A router maintains a routing table of various networks.

 

 Bridge:

A bridge is a multi-port device used for connecting two or more local area networks (LAN), possibly operating at different speeds.

Unlike hubs, they are intelligent devices, which exercise discretion while forwarding data.

 

 Gateway:

A gateway is a network device that connects two or more networks together.

It is used to translate data from one network protocol to another, so that devices on the different networks can communicate with each other.

 Q9. Differentiate between the following:

1.      LAN, MAN, WAN

2.      Internet and WWW

3.      Email and Chat

4.      Firewall and Antivirus

 a. .

Network	LAN	MAN	WAN
Full Form	Local Area Network	Metropolitan Area Network	Wide Area Network
Geographic scope	Small area	City or metropolitan area	Large geographic area
Ownership	Single organisation	Public or private organisation	Telecommunications company
Purpose	Connecting computers and devices within a single organisation	Connecting LANs within a city or metropolitan area	Connecting LANs and MANs over a large geographic area
Speed	High	Moderate	Low
Latency	Low	Moderate	High
Cost	Low	Moderate	High

 

b.

Internet	WWW
A global network of computers	A system of interlinked hypertext documents
To connect computers and allow them to communicate with each other	To provide a way to access information on the internet
TCP/IP protocol	HTTP protocol
Email, file sharing, video conferencing	Websites, web browsers, search engines

c.

d.

Firewall	Antivirus
To protect your computer or network from unauthorised access	To protect your computer from viruses, malware, and other malicious software
Monitors and controls incoming and outgoing network traffic	Scans your computer for viruses, malware, and other malicious software
Hardware firewalls, software firewalls	Behaviour-based antivirus
Protects your computer or network from unauthorised access	Protects your computer from viruses, malware, and other malicious software

 

Q10. What are cookies?

Cookies are small text files that a website saves on your computer or mobile device when you visit the site. They are used to remember your preferences, such as your language, font size, and other display preferences. They can also be used to track your browsing activity across different websites.

Q11. Define the following:

1.      Protocol

2.      Cyber crime

3.      Cyber law

4.      Digital Literacy

Protocol: A protocol is a set of rules that define how data is formatted, transmitted, and received between devices on a network.

Cyber-crimes: Cyber-crimes are the crimes related to the misuse of computers or the internet such as theft, fraud, forgery. E.g. Phishing, Malware, Cyber-bullying and Identity theft. Cyber-crime as an unlawful act where in the computer is either a tool or a target or both.

Cyber law: Cyber law is a broad term that refers to the legal issues related to the use of computers and the internet. E.g. Intellectual property: Cyber law deals with the protection of intellectual property rights in the digital age, such as copyright, trademark, and patent law.

Digital Literacy: Digital literacy refers to raising knowledge and awareness about technology such as desktop computers, smartphones, tablets, and other electronic gadgets. It also includes familiarity with software tools and the internet.

Q12. Explain TCP/IP Model.

The TCP/IP is the glue which holds the internet and WWW  together .A set of communication protocols allows computers to connect to each other and exchange data over the internet. It is divided into four layers:

1. Physical layer
2.  Data link layer
3. Network layer
4. Transport layer

Q13. List various protective measures that can be taken for network security.

1.      Never click on a suspicious link.

2.      Make sure that passwords are strong and are changed frequently.

3.     Never disclose personal information such as date of birth, account details, passwords, credit and debit card details.

4.      Do not post any offensive content on social networking site.

5.      Use updated antivirus and firewall.

 

   Q14. Define Topology and its types.

Network topology is the arrangement of the elements (links, nodes, etc.) of a communication network.

1.     In bus topology, there is a long cable, called backbone cable (or simply backbone), that connects various nodes through a connector called tap.

2.      In ring topology, all the devices are attached through a cable in the form of a ring.

3.      In star topology, all the devices are connected to the central controller called hub.

4.      In mesh topology, all nodes are connected with every other node in the network.

5.      In Tree topology is a combination of star and bus topology.

Q15. Write a short note on the following:

1.      TELNET

2.      FTP

3.      DNS

TELNET: Telnet stands for terminal network. It is a client server-based application that allows the user working on one system to login and access a remote system

FTP: FTP is a File transfer Protocol used for transferring files from one machine to another

DNS: The Domain Name System (DNS) is a hierarchical naming system for computers, services, or any resource connected to the Internet or a private network.

Q16. Write a short note on Following

MAC Address

IP Address

A MAC (Media Access Control) address is a unique identifier assigned to network interfaces for communications on the physical network segment.

Format: It's usually a 48-bit address written as six pairs of hexadecimal digits, separated by colons or hyphens. 

The first half (MM:MM:MM) of a MAC address contains the ID number of the adapter manufacturer. The second half (SS: SS: SS) of a MAC address represents the serial number assigned to the adapter (NIC) by its manufacturer. 

 IP Address

Every machine in a network has another unique identifying number, called its IP Address. An IP address is a group of four bytes (or 32 bits) each of which can be a number from 0 to 255. A typical IP address looks like this: 59.177.134.72

Q17. Explain Domain Name system

It is practically impossible for a person to remember the IP addresses of all the computers one may have to communicate with. Therefore, a system has been developed which assigns names to some computers (web servers) and maintains a database. These names are called Domain Names. Examples: cbse.nic.in

Generic Domain Names:

 ·com - commercial business

 ·edu - Educational institutions

 ·gov - Government agencies

 ·mil - Military 

·net - Network organizations

 ·org - Organizations (nonprofit)

 Country Specific Domain Names:

 .in - India

 ·au - Australia ·ca - Canada 

.us - United States of America

Q18. What do you mean by Network Security Tools and Services?

1. Firewalls

• What It Does: Blocks unwanted internet traffic to protect your computer.
• Like: A security guard at the entrance of your house.

2. Antivirus Software

• What It Does: Detects and removes harmful software from your computer.
• Like: A medicine that cures your computer from infections.

3. Password Managers

• What It Does: Stores and manages your passwords securely.
• Like: A secure vault where you keep all your keys (passwords) safe and organized.

4.Cyber Law Cyber laws are the laws for systematic use of e-resources, for example, e-business, and serve as a measure against illegal cyber-crime. Various cyber laws have also been enacted to prevent cyber-crimes

Q19. List some Protective Measures while accessing Internet for staying safe while using the internet.

1. Use Strong Passwords:

   • What to Do: Make passwords long and mix letters, numbers, and symbols.
   • Why: Harder for hackers to guess.

2. Keep Your Software Updated:

   • What to Do: Update your apps and operating system regularly.
   • Why: Fixes security holes and keeps you safe.

3. Be Careful with Links:

   • What to Do: Don’t click on suspicious links in emails or messages.
   • Why: Protects you from scams and malware.

4. Share Personal Info Wisely:

   • What to Do: Only give out personal details to trusted sites.
   • Why: Keeps your private information safe.

5. Install Antivirus Software:

   • What to Do: Use software that scans for and removes viruses.
   • Why: Protects your computer from harmful programs.

6. Secure Your Wi-Fi:

   • What to Do: Set a strong password for your home Wi-Fi.
   • Why: Prevents others from accessing your network.

7. Back Up Your Data:

   • What to Do: Save copies of important files in a separate location.
   • Why: Protects your data in case of loss or damage.

8. Avoid Public Wi-Fi for Sensitive Activities:

• What to Do: Don’t use public Wi-Fi for online banking or shopping.
• Why: Public networks are less secure.

Q20. Mention Some Cybercrime and Cyber Threats.

Cybercrimes are the crimes related to the misuse of computers or the Internet such as theft, fraud, and forgery

1.  Cyber bullying Harassment or bullying inflicted through the use of electronic or communication devices such as computer, mobile phone, laptop, etc.

2.   Cyber stalking Use of electronic communication by a person to follow a person or attempts to contact a person to foster personal interaction repeatedly despite a clear indication of disinterest by such person. 

3.  Online Job Fraud An attempt to defraud people who need employment by giving them a false hope/ promise of better employment with higher wages. 

4.  Vishing To seek personal information like Customer ID, Net Banking password, ATM PIN, OTP, Card expiry date, CVV etc. through a phone call.

5.   SMSing Use of mobile phone text messages to lure victims into calling back on a fraudulent phone number, visiting fraudulent websites or downloading malicious content via phone or web.

6.   SIM Swap Scam Getting a new SIM card against a registered mobile number

7.   Credit card (or debit card) fraud an unauthorized use of another's credit or debit card information for the purpose of purchases or withdrawing funds from it. 

8.  Identity theft Dishonestly making use of the electronic signature, password or any other unique identification feature of any other person. 

9.  Spamming Persuading a recipient to buy a product or service, or visit a website via email, SMS, MMS where he can make purchases. 

10.  Ransomware The victim is asked to pay the demanded ransom to get his device decrypt