Computer Networks

Both A and R are true and R is the correct explanation of A.

Explanation
ARPANET, jointly designed and named by the Advanced Research Projects Agency (ARPA) and the US Department of Defense (DoD), was the first computer network and came into existence in 1969. The objective of creating ARPANET was to develop a reliable communication network for the US military defense services, enabling them to send and receive instant messages and share data.

A is true but R is false.

Explanation
Internet cookies are small text files that contain small pieces of data such as usernames, passwords, and user preferences while surfing the internet. They are messages transmitted by a web server to a web browser, allowing the server to keep track of the user's activity on a specific website.

Both A and R are true and R is the correct explanation of A.

Explanation
A router is considered as a more reliable and intelligent device than a hub or switch because it has advanced capabilities to analyze the data being sent over a network, decide or alter how it is packaged, and send it to different computer networks.

Both A and R are true but R is not the correct explanation of A.

Explanation
PANs (Personal Area Networks) are small networks used to establish communication between a computer and other devices in proximity, typically up to 10 meters (20 to 30 sq.ft.). On the other hand, a WAN (Wide Area Network) spans a large geographical area across countries and continents. A WAN can cover an area with a radius spanning hundreds of kilometers.

Both A and R are true but R is not the correct explanation of A.

Explanation
A repeater is a device that amplifies a signal transmitted across the network so that the signal is received in the same way it is sent. A hub is a hardware device used to connect several computers together using different ports.

Both A and R are true and R is the correct explanation of A.

Explanation
VoIP stands for Voice over Internet Protocol, and it is a technology that allows us to make voice calls using a broadband connection instead of a regular phone line. The voice calls are first digitized, compressed, and then fragmented into small packets, which are then relayed by Internet Protocol (IP) across the network.

A is true but R is false.

Explanation
A protocol defines the set of rules and regulations applicable for data sharing and communication over a network. It is a formal description of message formats and the rules that devices must follow to exchange those messages. However, Local Area Network (LAN) is not an example of a protocol, rather, it is a type of computer network.

Both A and R are true and R is the correct explanation of A.

Explanation
A Gateway is a network device that connects dissimilar networks. Gateway provides the necessary translation of data received from network into a format or protocol recognized by devices within the internal network establishing an intelligent connection between the two.

(a) The most appropriate block where RCI should plan to install the server is faculty recording block as maximum number of computers are placed there.

(b) The most appropriate block-to-block cable layout to connect all three blocks for efficient communication is shown below:

(c) LAN

Reason — The network is a Local Area Network (LAN) because it connects computers within a single campus in Kolkata, covering short distances (60m, 70m, 120m) between blocks.

(d) Satellite

Reason — RCI should use Satellite communication for global connectivity. Satellite provides worldwide coverage, enabling students from anywhere to access online corporate training and ensuring consistent, reliable communication over long distances.

(a) The most suitable topology is star topology to connect the computers of all wings.

(b) The server should be installed in Wing A because Wing A has the highest number of computers (150), and this will help reduce network traffic.

(c) The Hub/Switch or should be placed in all the wings.

(d) The economic way to provide internet accessibility to all the wings is to use the proxy server at Wing A and connect to the internet through a dial-up network.

(a) The most suitable location for the server is the Admin Building because it has the highest number of computers (110). Placing the server here ensures maximum connectivity and data access for the maximum number of users.

(b) A star topology can be used to connect the Admin building directly to other buildings. This layout optimizes connectivity and data transfer efficiency within the Chennai campus. The cable layout is shown below:

(c) A Firewall/Router is recommended for network security and controlling internet usage within the campus. It filters network traffic based on security rules, protecting against unauthorized access and threats.

(d) Video conferencing

Reason — Video conferencing is the best option for online face-to-face communication. It provides real-time audio and video capabilities, facilitating effective collaboration between Chennai and Delhi offices.

(a) The most suitable place to install server of the university is Admin center because it has the maximum number of computers. This will help to keep maximum percentage of the network traffic local.

(b) A star topology is ideal for connecting the schools and centre.

(c) A Switch should be installed in each school/centre to efficiently connect all computers. Switches provide high-speed connections and efficient data transmission within local networks.

(d) A Wide Area Network (WAN) will be formed to connect the university's admission office in the closest big city, which is over 350 km away. WANs cover large geographic areas, such as different cities or countries.

(a) Human Resource will be the most appropriate block where TUC should plan to install the server due to maximum number of computers (125).

(b) Block-to-block cable layout to connect all the buildings is shown below:

(c) Satellite Link

Reason — A Satellite Link would be the best option to connect the new office in Bengaluru with its London office. Satellite links offer reliable and high-speed communication over long distances, making them ideal for connecting offices in different locations.

(d) Switch

Reason — A Switch is recommended to connect each computer in each building. Switches allow multiple devices to connect and communicate within a local network.

(e) Two popular Open Source Software Operating Systems are Linux and Open Solaris.

(a) The most suitable cable layout or network topology for connecting the zones is a bus topology.

(b) The most suitable place (i.e., Zone) to house the ERP and BI Server is Zone Z as it has the maximum number of computers which will reduce cabling cost.

(c)

(i) As per the suggested layout, separate repeaters need not to be installed as distance among zones is not exceeding 70m.

(ii) Hub/Switch should be placed in each zone.

(d) An economic type of cable is Ethernet or Coaxial cable as it can connect two computers at an economic rate though it provides lesser speed than other expensive methods.

(a)

(i) For connecting the Back Office and Work Office, a LAN (Local Area Network) would be suitable as they are 70m apart.

(ii) For connecting the Back Office and South Office, a WAN (Wide Area Network) is required due to the long distance (1952 km).

(b) Switch/Hub

Reason — A switch or hub is essential for connecting all computers within each office as they facilitate communication between devices on the same network. They manage network traffic efficiently, ensuring smooth data transfer and communication.

(c) Optical fiber

Reason — Optical fibre is recommended for very effective and fast communication in New Delhi's local office units. It offers high-speed data transmission, reliability, making it ideal for modern network infrastructures.

(d) The cable/wiring layout is shown in the diagram below:

An effective method for connecting the company's regional office is Satellite.

(a) Cable layout of connection between the blocks is shown below:

(b) The most suitable place to house the server would be the HR Centre because it has the highest number of computers (115).

(c) A Switch/Hub should be placed in each block to efficiently connect all computers.

(d) A MAN (Metropolitan Area Network) will be formed to link the sales counters situated in various parts of the same city.

(a) The most appropriate location for the server would be the ADMIN building because it has the highest number of computers (110).

(b) A star topology can be used to efficiently connect various buildings within the Mumbai campus. Cable layout is shown in the diagram below:

(c) A Switch/Hub is recommended to interconnect all the computers of various buildings within the Mumbai campus.

(d) A dynamic website will be more suitable for the company's purpose. Dynamic websites can be updated regularly and interact with databases, allowing students to access personalized information such as their results after registering.

(e) Video conferencing

Reason — Video conferencing would be the most suitable option for online face-to-face communication between the ADMIN office of the Mumbai campus and Delhi Head Office. It offers real-time audio and video capabilities, enhancing collaboration and communication effectiveness.

All of the above

Reason — A computer network is a collection of interconnected computers and other hardware devices using communication channels to share data and various resources, including hardware and software resources.

Repeater

Reason — A repeater is a network device that regenerates and retransmits weak or corrupted signals so that the signal is received in the same way as it was sent.

To connect LANs

Reason — Bridges are devices that connect one LAN to another LAN that uses the same protocol.

Source and Destination address

Reason — Each IP packet in a computer network must contain both the source address (the address of the sender or originator) and the destination address (the address of the intended recipient). This ensures that the packet is routed correctly through the network to reach its destination.

Wi-Fi

Reason — Wi-Fi is not a communication channel but a technology that uses communication channels like radio waves to transmit data wirelessly over short distances. In contrast, satellite, microwave, and radio waves are specific types of communication channels used for transferring information over various distances.

Metropolitan Area Network

Reason — MAN stands for Metropolitan Area Network.

Tree

Reason — The shape of tree topology network is that of an inverted tree with the central root branching and sub-branching to the extremities of the network.

Bus

Reason — Bus topology is a multi-point configuration, i.e., several devices are connected to a main long cable (usually co-axial cable) which acts as a backbone.

LAN

Reason — LAN is the smallest network among the options provided. It covers a small geographical area like a home, office, or school. It typically covers an area of up to 10 kilometers.

HTTP

Reason — Hyper Text Transfer Protocol (HTTP) is the set of rules for transferring hypertext content on World Wide Web.

Star

Reason — The figure shows a Star network topology where devices like computers and printers are connected directly to a central hub.

Gateway

Reason — A gateway is a network device that connects dissimilar networks, establishes an intelligent connection between a local network and external networks with completely different structures.

Avast

Reason — Avast is not a web browser, it is an antivirus software. Chrome, Firefox, and Edge are examples of browsers.

Dynamic web page

Reason — A dynamic web page uses scripting languages to display changing content on the web page, such as stock prices and weather information.

VoIP

Reason — VoIP (Voice over Internet Protocol) is a communication methodology designed to deliver both voice and multimedia communications over Internet protocol.

MAN

Reason — A television cable network is an example of a MAN (Metropolitan Area Network) because it covers a city or large area, typically up to 30-40 km.

The Internet is a world-wide network of computer networks. It connects many smaller networks together and allows all the computers to exchange information with each other.

A network is a collection of interconnected computers and other devices to share data and other resources (hardware and software resources).

The various types of topologies are as follows:

1. Bus or Linear topology
2. Ring or Circular topology
3. Star topology
4. Tree topology
5. Mesh topology

1. Bus Topology — Bus topology is a multi-point configuration, i.e., several devices are connected to a main long cable (usually co-axial cable) which acts as a backbone. Nodes are connected by drop lines and taps. A drop line is a connection between long cable and devices and taps are the connectors that are punctured inside the main cable. The data flows from one end of the cable to the other. The cable has terminators at both ends which absorb signals when the signal reaches the end, preventing signal bounce. However, as the signal travels a long distance, it becomes weaker and weaker. It works well for small networks.

2. Star Topology — In star topology, each communicating device is connected to a central controller called a hub or switch. The devices in star topology send and receive data indirectly, the data passes to and from the hub. The central node can be either a broadcasting device (hub) or a unicast device (switch).

(a) Baud — Baud refers to the number of discrete signal elements transmitted per second. It is the measuring unit of the data transfer rate.

(b) Communication channel — Communication channel is also known as transmission media through which data or signal is transferred between two communicating devices, i.e., from one system to another system, through wires or without wires.

(c) Hub — A hub is a networking device having multiple ports that are used for connecting multiple computers or segments of a LAN together.

(d) Repeater — A repeater is a device that amplifies a signal transmitted across the network so that the signal is received in the same way it is sent.

A MODEM (Modulator Demodulator) is an electronic device that enables a computer to transmit data over telephone lines. It is a device used to convert digital signals into analog signals and vice versa.

The functioning of internal modem and external modem is as follows:

1. Internal modem — These are attached to the internal slot of the motherboard. They modulate digital data into analog signals for transmission and demodulate incoming analog signals into digital data.

2. External modem — It is a small box connected to the communication port of the computer. It works similarly to the internal modem. The only difference is that it is placed outside the CPU box.

(a) PPP — Point-to-Point Protocol (PPP) is one of the most commonly used data link protocols. It is utilized to establish a direct connection between two nodes and can provide various functionalities such as connection authentication, transmission, encryption, and compression. Communication occurs through a high-speed modem, and PPP is used to connect telephone dial-up lines to the internet.

(b) POP3 — Post Office Protocol version 3 (POP3) is a simple and standard method for accessing mailboxes and downloading messages to local computers. Users can receive messages using the POP3 protocol. An advantage of POP3 is that once messages are downloaded, an internet connection is no longer necessary to read the mail, as they are saved on the computer's hard disk.

(c) VoIP — Voice over Internet Protocol (VoIP) is utilized for transmitting voice communications. Voice calls undergo digitization, compression, and fragmentation into small packets, which are then transmitted across Internet Protocol (IP) networks. VoIP implementation allows users to carry voice traffic efficiently over an IP network.

(d) IRC — Internet Relay Chat (IRC) is an application layer protocol that enables users to share text messages. The sender sends a request to an IRC server, which then forwards the request to another client, facilitating communication between users.

(a) Hubs — Hub is a multi-port and unintelligent network device which simply transfers data from one port of the network to another. It is used to connect several computers together with different ports. When the data packet reaches one port, it is copied to all other ports of the hub without changing the destination address. They can both send as well as receive information but only one task at a time. Hubs can be either active or passive.

(b) Repeaters — A repeater is a device that amplifies a signal transmitted across the network so that the signal is received in the same way as it is sent. It operates only at the physical layer of the OSI model. A repeater is a two-port network device that strengthens the signal intensity and connects two identical networks. A repeater does not change the functionality of the network; instead, it strengthens the signal before it degrades.

(c) Routers — A router is a networking device that forwards data packets from the source machine to the destination machine over a network using the shortest path available. It can handle different protocols. Routers utilize IP addresses to connect local area networks to the Internet. In contrast to a hub or a switch, a router possesses advanced capabilities as it can analyze the data being transmitted over a network, make decisions on how it is packaged, and route it to different computer networks.

(d) Bridges — A bridge is a device that operates at both the physical layer and the data link layer of the OSI model. It connects multiple network segments (LANs) at the data link layer (Layer 2) of the OSI model. It is a smarter hub as it can filter network traffic on the basis of the MAC addresses.

(e) Gateways — A gateway is a network device that connects dissimilar networks. It provides the necessary translation of data received from one network into a format or protocol recognized by devices within another network. A gateway establishes an intelligent connection between a local area network and external networks with completely different structures.

(a) Modem

(b) Repeater

(a) Bus Topology

(b) Star Topology

The World Wide Web (WWW) is a set of protocols that allows us to access any document on the Net through a naming system based on URLs. The WWW also specifies a way, known as the Hypertext Transfer Protocol (HTTP), to request and send hypermedia documents over the Internet.

The Internet is a worldwide network of computer networks that allows all computers to exchange information with each other. They follow protocols like TCP/IP (Transmission Control Protocol/Internet Protocol) for communication.

The WWW is a small part of the Internet. We can say that the Internet is a highway that offers many services and features, and the WWW is a vehicle (like a truck) that uses this highway to transport information.

Mani can send his trip report with images and videos to his mentor through email by attaching files or using chat platforms like WhatsApp or Facebook Messenger, as these platforms support the sharing of image and video files.

Ram should use social networking platforms like Instagram and Facebook to advertise his handicrafts because they offer targeted advertising options that can reach a broad and diverse audience. Facebook provides a marketplace where he can sell his products directly and its cost effective.

A WiFi card is either an internal or external Local Area Network adapter with a built-in wireless radio and antenna. It is used in a desktop computer to enable a user to establish an Internet connection. WiFi cards are known as wireless fidelity cards because they allow users to set up connections without any wires.

HTTPS stands for Hypertext Transfer Protocol Secure. It's a protocol that secures communication between two systems, like a browser and a web server, by encrypting data during transmission. When a user accesses a website using HTTPS, a secure connection is established, verifying the server's identity with digital certificates. This encryption and authentication ensure data privacy and integrity, crucial for protecting sensitive information such as passwords and financial data from interception or tampering by malicious entities on the Internet.

A hub is a multi-port and unintelligent network device that simply transfers data from one port of the network to another. It is a hardware device used to connect several computers together using different ports.

Active hubs electrically amplify the signal as it passes from one connected device to another. They are often used like repeaters to extend the length of a network. In contrast, passive hubs allow the signal to pass from one computer to another without any alteration or amplification.

Some services provided by a server on a network are:

1. Equipment/Resource Sharing — High quality printers and photocopiers are often designed to connect directly to a network and all authorised users can share the equipment. A server is responsible for such a resource sharing request.
2. Centralised File Saving for Data Sharing — Servers help the user save files to their home directories on the file server, workers can load their documents on any networked computer.
3. Centralised Virus Scanning — Most file servers run virus scanners constantly to detect and take care of viruses introduced by any user on any computer.
4. Centralised Backups — High-capacity tape devices in the file server back up all users' work, usually every night. In case of system failure (or worker failure), lost work can be recovered quickly and easily.

Mesh network topology is easy to expand.

Switch filters the data and router handles different protocol.

A network is an interconnected collection of autonomous computers that can share and exchange information and resources.

Major goals and applications of networks are :

1. Resource Sharing — Through a network, data, software and hardware resources can be shared irrespective of the physical location of the resources and the user.
2. Reliability — A file can have its copies on two or more computers of the network, so if one of them is unavailable, the other copies could be used. That makes a network more reliable.
3. Reduced Costs — Since resources can be shared, it greatly reduces the costs.
4. Fast communication — With networks, it is possible to exchange information at very fast speeds.

A switch is a device that is used to segment networks into different sub-networks, called subnets or LAN segments to prevent traffic overloading.

A switch is responsible for filtering i.e., transforming data in a specific way and for forwarding packets between LAN segments. To insulate the transmission from the other ports, the switch establishes a temporary connection between source and destination and then terminates the connection once the conversation is done.

A repeater is a network device that amplifies and restores signals for long-distance transmission. It is used in long network lines, which exceed the maximum rated distance for a single run. Over distance, the cables connecting a network lose the signal transmitted. Repeaters are installed along the way in the network to ensure that data packets reach their destination without any degradation of the message.

A router is a network device that forwards data from one network to another. A router works like a bridge but can handle different protocols. Based on a network road map called a routing table, routers can help ensure that packets are travelling the most efficient paths to their destinations. If a link between two routers fails, the sending router can determine an alternate route to keep traffic moving.

A bridge is a device that links two networks together. Bridges are smart enough to know which computers are on which side of the bridge, so they only allow those messages that need to get to the other side to cross the bridge. Bridges can handle networks that follow same protocols.

A gateway is a network device that connects dissimilar networks. It establishes an intelligent connection between a local network and external networks with completely different structures.

In enterprises, the gateway is the computer that routes the traffic from a workstation to the outside network that is serving the Web pages. In homes, the gateway is the ISP that connects the user to the Internet.

Error 404 was displayed because the URL Rinku typed in the address bar of her browser is not valid or the webpage she is trying to access does not exist on the server. This can happen if the URL is misspelled, the webpage has been removed or renamed, or the server is down. To avoid this, Rinku can double-check the URL for any typos, try searching for the webpage using a search engine, or contact the website administrator to see if the webpage has been moved or removed.

Hubs are preferred over repeaters when the distance between the terminals of the network is less and signals are not lost during transmission.

Bridges are preferred over hubs when we need to connect multiple networks.

We prefer switch over other network devices when we need to establish two-lane communication, facilitating send and receives at the same time. A switch provides full bandwidth to each connection and sends traffic only to appropriate connections, thus preventing traffic overload.

Shubham can add the Adobe Flash Player plug-in to his browser by going to the Adobe Flash Player download page, clicking on the "Download Now" button, selecting the correct operating system and browser type, running the downloaded installer file, following the installation prompts, and restarting his browser after the installation is complete, which should then allow him to play the video in his browser.

The steps to install add-ons in google chrome web browser are as follows:

1. Open Google Chrome.
2. Go to the Chrome Web Store.
3. Search for the add-on.
4. Click "Add to Chrome."
5. Confirm the installation.
6. Access and manage the add-on from the toolbar or extensions menu.

Cookies are small text files stored on user's computer and created and used by websites.

Cookies are created by websites to remember basic information of the user and to record the user's browsing activity which helps in enhancing the user experience and making browsing time more productive.

Email address has two main parts — a username and domain name. The username comes before '@' and domain name comes after it.

For example, in abc@gmail.com, abc is the username and gmail.com is the domain name.

The domain name is www.cbse.nic.in indicating the network domain hosting the website, while the URL is www.cbse.nic.in/question_paper.html, specifying the specific page or resource within that domain.

True

Reason — Protocol means a set of rules and regulations that governs a network. It represents the communication methods which are to be followed by the sending and receiving devices.

False

Reason — A repeater is a network device that amplifies a signal transmitted across the network, ensuring that the signal is received in the same way as it is sent. It operates at the physical layer of the OSI model and does not handle different protocols. On the other hand, a router operates at the network layer and is capable of handling different protocols.

False

Reason — A hub is known as an unintelligent device on the network that simply transfers data from one port of the network to another.

True

Reason — A website is a location on a web server where users can access and interact with digital assets (web pages, images, videos, audios etc) through a web browser.

True

Reason — A document that uses the HTTP (Hypertext Transfer Protocol) to be accessed and retrieved from a web server is called a web page.

False

Reason — A router is a device used to segment networks into sub-networks or subnets, while a switch is a network device used to interconnect computers or devices on a network.

False

Reason — Email helps us to send and receive messages through text using SMTP (Simple Mail Transfer Protocol) and POP3 (Post Office Protocol 3) protocols.

False

Reason — In star topology, each computer is connected to a central controller called hub or switch.

False

Reason — Applications such as WhatsApp, Slack, Skype, Yahoo Messenger, Google Talk, Facebook Messenger, Google Hangout, etc., are examples of instant messengers.

True

Reason — A router uses IP address to connect a local area network to the internet.