Class 12 Computer Network important Questions for board exam 2024-25 PART -1

Question 1 : What is a Coputer Network?

What do you mean by Coputer Network?

Explain Computer Network

A computer network is a system of interconnected computers that communicate with each other to share resources and information. Networks can vary in size and complexity, from small local networks connecting a few devices within a single building to vast global networks connecting millions of devices around the world, like the internet.

Question No 2: What are key components of Computer Network?

Here are some key components and concepts related to computer networks:

Nodes: Devices or endpoints on a network, such as computers, printers, servers, and smartphones.
Network Interface Cards (NICs): Hardware components that connect a computer to a network.
Switches and Routers: Devices that manage traffic within a network (switches) or between different networks (routers). Switches direct data to specific devices on a local network, while routers connect multiple networks and manage data traffic between them.
Protocols: Rules and standards that govern how data is transmitted and received over the network. Common protocols include TCP/IP (Transmission Control Protocol/Internet Protocol), which is the foundation of internet communication.
IP Addresses: Unique numerical identifiers assigned to each device on a network, allowing them to communicate with each other.
Network Topologies: The arrangement of network devices and how they are connected. Common topologies include star, ring, bus, and mesh.
Local Area Network (LAN) and Wide Area Network (WAN): LANs cover a small geographic area, like an office or home, while WANs span larger areas, potentially across cities or countries.
Wireless Networks: Networks that use wireless technologies like Wi-Fi or Bluetooth to connect devices without physical cables.
Network Security: Measures and protocols used to protect data and resources on a network from unauthorized access and attacks.

In essence, computer networks enable devices to communicate, share resources, and access information efficiently.

Question 3 What are the advantages of Computer network?

Computer networks offer numerous advantages that enhance both personal and organizational productivity. Here are some key benefits:

Resource Sharing: Networks allow multiple devices to share resources such as printers, files, and internet connections. This reduces redundancy and saves costs by enabling centralized access to hardware and data.
Communication: Networks facilitate various forms of communication, including email, instant messaging, video conferencing, and VoIP (Voice over Internet Protocol), making it easier for people to collaborate and share information in real time.
Data Management and Storage: Networks enable centralized data storage and management, making it easier to back up, access, and manage data from different locations. This improves data consistency and security.
Scalability: Networks can be expanded to include additional devices and users with relatively little effort. This flexibility supports growth and adapts to changing needs.
Cost Efficiency: By centralizing resources and services, networks reduce the need for duplicate hardware and software, leading to cost savings. Additionally, cloud services and network-based applications often provide scalable and cost-effective solutions.
Remote Access: Networks, especially with technologies like VPNs (Virtual Private Networks), allow users to access resources and work remotely from various locations, improving flexibility and productivity.
Security: While networks can introduce security challenges, they also provide tools and technologies to enhance security, such as firewalls, encryption, and access controls. Centralized management helps in monitoring and protecting data.
Automation: Networks enable automation of tasks and processes, such as data backups, updates, and system management, leading to increased efficiency and reduced manual effort.
Data Backup and Recovery: Centralized network storage solutions often include automated backup and recovery options, helping to protect data from loss and ensuring business continuity.

Question What are the computer netowrk devices? Explain them.

Computer networks use various devices to facilitate communication, manage traffic, and ensure security. Here’s an overview of some key network devices and their functions:

1. Router

Function:

A router connects multiple networks together, such as a local area network (LAN) to the internet (a wide area network, WAN). It directs data packets between networks, determines the best path for data to travel, and manages traffic to prevent congestion.

Example:

In a home network, a router connects your home devices (like computers and smartphones) to your internet service provider (ISP), allowing them to access the internet.

2. Switch

Function:

A switch connects devices within a LAN and directs data to the specific device intended to receive it. It operates at the data link layer (Layer 2) of the OSI model and uses MAC addresses to forward data packets to the correct device.

Example:

In an office, a switch connects computers, printers, and servers within the network. If a computer sends a print job, the switch ensures the data reaches the correct networked printer.

3. Hub

Function:

A hub is a basic network device that connects multiple devices in a LAN but does so without any intelligent data forwarding. It broadcasts data packets to all connected devices, regardless of the intended recipient. This can lead to network inefficiencies and collisions.

Example:

Hubs are less common in modern networks due to their inefficiency, but they might still be used in simple, small networks where advanced features are not required.

4. Access Point (AP)

Function:

An access point connects wireless devices to a wired network, extending the network’s range and enabling Wi-Fi connectivity. It acts as a bridge between the wired network and wireless clients.

Example:

In a large office, additional access points might be deployed to provide strong Wi-Fi coverage throughout the building, allowing employees to connect their laptops and smartphones wirelessly.

5. Modem

Function:

A modem (short for modulator-demodulator) converts digital data from a computer into analog signals for transmission over phone lines or cable systems, and vice versa. It connects a home or office network to the internet.

Example:

In a home network, the modem connects to the ISP's infrastructure and provides internet access, which is then distributed by the router.

6. Firewall

Function:

A firewall monitors and controls incoming and outgoing network traffic based on predetermined security rules. It protects the network from unauthorized access and threats by filtering traffic.

Example:

A corporate firewall may block access to certain websites or external services to ensure that employees can only access approved resources and to protect against cyber attacks.

7. Network Interface Card (NIC)

Function:

A NIC is a hardware component installed in a computer or other device that allows it to connect to a network. It can be wired (Ethernet NIC) or wireless (Wi-Fi NIC).

Example:

A desktop computer with an Ethernet NIC can connect to a LAN via a network cable, while a laptop with a Wi-Fi NIC can connect to a wireless network.

8. Repeater

Function:

A repeater amplifies or regenerates signals to extend the range of a network. It is used to boost weak signals over long distances, ensuring reliable communication.

Example:

In a large building, repeaters can be used to strengthen the signal of a wireless network so that it reaches all areas, including those far from the main access point.

9. Bridge

Function:

A bridge connects and filters traffic between two or more network segments, effectively creating a single, larger network. It operates at the data link layer and helps reduce network congestion by dividing traffic.

Example:

A bridge might connect two separate LANs in different parts of a building, allowing them to function as a unified network.

10. Gateway

Function:

A gateway connects networks that use different protocols, enabling communication between them. It often translates data between different formats or protocols.

Example:

A network gateway might connect a company's internal network (using one protocol) to an external cloud service (using another protocol), ensuring seamless data exchange between them.

These network devices each play a crucial role in managing and facilitating communication, connectivity, and security within and between networks.

What are the differences between Router and Repeater ?Explain them with example.

Routers and repeaters are both essential network devices, but they serve different functions. Here’s a detailed comparison between the two, along with examples to illustrate their roles:

Router

Function:

A router connects multiple networks together and directs data packets between them. It operates at the network layer (Layer 3) of the OSI model and manages traffic within and between networks by determining the best path for data to travel.

Key Features:

Network Segmentation: Routers can divide a large network into smaller, more manageable subnetworks (subnets).
IP Addressing: Routers assign IP addresses to devices on the network, typically using DHCP (Dynamic Host Configuration Protocol).
Traffic Management: Routers use routing tables and protocols (like OSPF or BGP) to determine the best route for data packets to reach their destination.
Security Features: Routers often include built-in firewalls and other security measures to protect the network from unauthorized access.

Example:

Home Network: In a typical home setup, a router connects the home network to the internet. It allows multiple devices, such as laptops, smartphones, and smart TVs, to access the internet simultaneously. The router assigns IP addresses to these devices, manages data traffic, and provides security features like a firewall.

Repeater

Function:

A repeater amplifies or regenerates weak signals to extend the range of a network. It operates at the physical layer (Layer 1) of the OSI model and is used to boost signals over long distances, ensuring that data can travel further without degradation.

Key Features:

Signal Boosting: Repeaters regenerate or amplify signals to overcome distance limitations and signal loss in a network.
No Network Traffic Management: Repeaters do not manage network traffic or make routing decisions. They simply pass along the signals they receive.
Simple Operation: Repeaters work at a basic level, amplifying and retransmitting signals without making decisions about data paths or addressing.

Example:

Large Office Building: In a large office with Ethernet cabling, a repeater might be used to extend the range of the network beyond the maximum distance that Ethernet can support (typically 100 meters or about 328 feet). For example, if a network cable runs from one side of the building to the other, a repeater placed in the middle of the cable run would amplify the signal, ensuring that the data reaches the far end of the cable without loss.

Summary of Differences

Purpose:
- Router: Connects and manages multiple networks, directs data traffic, and provides IP addressing and security features.
- Repeater: Extends the range of a network by amplifying or regenerating signals.
Layer of Operation:
- Router: Operates at the network layer (Layer 3).
- Repeater: Operates at the physical layer (Layer 1).
Functionality:
- Router: Makes decisions about data routing and manages network traffic.
- Repeater: Simply amplifies or retransmits signals to overcome distance limitations.
Use Cases:

Router: Used to connect a home or office network to the internet or to connect multiple subnets within a larger network.
Repeater: Used to extend the range of a network where the signal might otherwise degrade due to distance.

Question What are the key difference between Gateway and Firewall?

Differences

Purpose:
- Gateway: Connects and translates between different networks or systems, enabling interoperability and communication across diverse network environments.
- Firewall: Protects a network by controlling and filtering traffic to prevent unauthorized access and threats.
Functionality:
- Gateway: Translates data formats or protocols and connects different network types. It can facilitate communication between systems that use different technologies.
- Firewall: Inspects and filters network traffic based on security rules to protect the network from threats and unauthorized access.
Layer of Operation:
- Gateway: Operates at various layers of the OSI model, depending on its specific function, including application (Layer 7) for application-specific gateways.
- Firewall: Primarily operates at the network (Layer 3) and transport (Layer 4) layers but can also have application-layer (Layer 7) capabilities in advanced firewalls.
Use Cases:

Gateway: Used when there is a need to connect and facilitate communication between different network protocols or technologies.
Firewall: Used to secure a network by enforcing access controls, monitoring traffic, and defending against malicious activities.

Purpose:

Bridge: Connects and filters traffic between network segments to create a unified network and reduce congestion.
Gateway: Connects different networks or systems that use different protocols or data formats, performing translation to enable interoperability.

Functionality:

Bridge: Operates at the data link layer (Layer 2) and uses MAC addresses to manage traffic between network segments. It helps in reducing network collisions and improving efficiency.
Gateway: Operates at various layers of the OSI model depending on its function and performs protocol translation or data conversion. It facilitates communication between disparate systems or networks.

Layer of Operation:

Bridge: Primarily operates at the data link layer (Layer 2), dealing with MAC addresses and Ethernet frames.
Gateway: Can operate at multiple layers, including the network layer (Layer 3) and application layer (Layer 7), depending on the type of protocol or data conversion required.

Use Cases:

Bridge: Used to connect and manage traffic between network segments within the same network environment, such as different VLANs (Virtual Local Area Networks).
Gateway: Used to connect and enable communication between different network technologies or protocols, such as linking an internal network to the internet or integrating different communication systems.

Question What is the difference between Hub and Switch?

Purpose:
- Hub: Connects multiple devices in a network and broadcasts data packets to all devices, leading to potential network inefficiencies.
- Switch: Connects multiple devices in a network and directs data packets to the specific device they are intended for, improving efficiency and reducing collisions.
Functionality:
- Hub: Operates at the physical layer (Layer 1) and has no intelligence regarding data forwarding or traffic management.
- Switch: Operates at the data link layer (Layer 2) and uses MAC addresses to intelligently forward data packets to the correct device.
Network Efficiency:
- Hub: Can lead to network congestion and collisions because it broadcasts data to all devices, regardless of the intended recipient.
- Switch: Reduces network congestion and collisions by sending data packets only to the intended recipient, based on MAC address information.
Performance:
- Hub: Typically results in slower network performance due to increased traffic and collisions.
- Switch: Provides better network performance by reducing unnecessary traffic and collisions through intelligent data forwarding.
Cost:

Hub: Generally less expensive due to its simplicity and lack of advanced features.
Switch: Typically more expensive, but the additional cost is offset by its improved performance and efficiency.

Question Define Modem.

A modem (short for modulator-demodulator) is a device that enables a computer or other digital devices to connect to and communicate over an analog network, such as a telephone line, cable system, or satellite link. It translates digital signals from a computer into analog signals that can be transmitted over these networks, and vice versa, converting incoming analog signals back into digital form.

Function of a Modem

Modulation:
- Process: Converts digital data from a computer into analog signals.
- Purpose: This is necessary because traditional telephone lines and other analog networks transmit signals in analog format.
Demodulation:

Process: Converts incoming analog signals from the network back into digital data that the computer can understand.
Purpose: This allows the digital data to be processed by the computer or device.