Question 1

Question 6Assertion. Hubs and switches can be replaced.Reason. While a hub is a broadcast device, a switch is a unicast device.

Accepted Answer

(b)Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.ExplanationBoth hubs and switches are used to connect multiple devices in a network. Hence they are replaceable with each other. Switches offer more efficient data transmission compared to hubs because they can direct data specifically to the intended device connected to it, unlike a hub that just sends data to all connected devices. This makes a switch more efficient for managing network traffic. Therefore, a hub is a broadcast device, a switch is a unicast device.

Question 2

Question 5What is the purpose of using a repeater in context of networking ?

Accepted Answer

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.

Question 3

Question 9Discuss the two technologies to connect to Internet wirelessly.

Accepted Answer

Two most common ways to connect to Internet wirelessly are :Wi-Fi — Wi-Fi refers to Wireless Fidelity, which lets us connect to the Internet without a direct line from our PC to the ISP. The WiFi wireless local area network standard is limited in most cases to only 100-300 feet (30-100 m). For Wi-Fi to work, we need:A broadband Internet connection.A wireless router, which relays our Internet connection from the ISP to the PC.A laptop or desktop with a wireless internet card or external wireless adapter.WiMAX — It is a wireless digital communications system. It can provide broadband wireless access (BWA) up to 30 miles (50 km) for fixed stations, and 3-10 miles (5-15 km) for mobile stations.

Question 4

Question 1Discuss various Network devices.

Accepted Answer

The various network devices are as follows :Modem — Modem stands for Modulator Demodulator. It is a computer peripheral device that allows us to connect and communicate with other computers via telephone lines. Modems come in two varieties :Internal modems — They are fixed within the computer.External modems — They are connected externally to a computer as other peripherals are connected.RJ-45 — RJ-45 refers to Registered Jack-45. It is an eight-wire connector, which is commonly used to connect computers on the local area networks (LANs), especially Ethernets.NIC (Network Interface Card) — The network interface card is a device that is attached to each of the workstations and the server, and helps the workstation establish all the important connections with the network. Each NIC that is attached to a workstation has a unique number identifying it, which is known as the node address. The NIC manufacturer assigns a unique physical address (48 bits) to each NIC card, which is known as MAC address.Ethernet Card — Ethernet Card is a type of Network Interface card, which is specific to Ethernet technology. An Ethernet card contains connections for either coaxial or twisted pair cables or both.Hub — A hub is a networking device having multiple ports that are used for connecting multiple computers or segments of a LAN together.Switch — A switch is a device that is used to segment networks into different sub-networks, called subnets or LAN segments. A switch is responsible for filtering i.e., transforming data in a specific way and for forwarding packets between LAN segments.Repeater — A repeater is a network device that amplifies and restores signals for long-distance transmission.Bridge — 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.Router — 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.Gateway — 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.WiFi Card — A WiFi card is either an internal or external Local Area Network adapter with a built-in wireless radio and antenna.

Question 5

Question 2Discuss various Network protocols.

Accepted Answer

The network protocol is a formal description of message formats and the rules that two or more machines must follow to exchange those messages.The various network protocols are as follows :HTTP (Hypertext Transfer Protocol) — HTTP is the set of rules for transferring hypertext on world wide web. It is an application level protocol with the lightness and speed necessary for distributed, collaborative, hypermedia information systems. It is a generic, stateless, object-oriented protocol which can be used for many tasks, such as name servers and distributed object management systems. The HTTP protocol consists of two fairly distinct items : the set of requests from browsers to servers and the set of responses going back to the other way.HTTPS (Hypertext Transfer Protocol Secure) — HTTPS is a secure version of HTTP protocol that uses the SSL/TLS protocol for encryption and authentication. HTTPS sends the data in encrypted form to make the transmission secure.FTP (File Transfer Protocol) — FTP is a standard for the exchange of files across internet. Files of any type can be transferred through it. FTP is also the name of a program or command. The objectives of FTP are to encourage indirect or implicit use of remote computers, to shield a user from variations in file storage systems among hosts.TCP/IP (Transmission Control Protocol/Internet Protocol) — It is the base communication protocol of the Internet. TCP is responsible for full-fledged data connectivity and transmitting the data end-to-end by providing other functions, including addressing, mapping and acknowledgement. IP is responsible for obtaining the address of the computer/device to which data is being sent.SLIP/PPP — SLIP (Serial Line IP) was the first protocol for relaying IP packets over dial-up lines. It defines an encapsulation mechanism, but little else. There is no dynamic address assignment, link testing, or multiplexing different protocols over a single link.PPP (Point to Point Protocols) is the internet standard for transmission of IP packets over serial lines. It is a data link protocol commonly used in establishing a direct connection between two networking nodes and enabling IP communication over this direct connection.Protocols used by email — The protocols mainly used with email accessing are IMAP, POP3, SMTP and HTTP.IMAP (Internet Message Access Protocol) is a standard protocol for accessing email from local server.The POP3 (Post Office Protocol 3) provides a simple, standardized way for users to access mailboxes and download messages to their computers.The SMTP (Simple Mail Transfer Protocol) is used when we send email to another email users. This can be used to send emails, not to receive them.HTTP protocol is not a protocol dedicated for email communications, but it can be used for accessing mailbox. Also called web based email, this protocol can be used to compose or retrieve emails from an email account. Hotmail, Gmail are examples of using HTTP as an email protocol.

Question 6

Question 3Briefly discuss wireless and mobile computing, and various techniques used for wireless and mobile computing.

Accepted Answer

Wireless computing refers to the method of transferring information between computing devices without a physical connection. For example, transmission between a personal data assistant (PDA), and a data source. Not all wireless communications technologies are mobile. Wireless communication is simply data communication without the use of landlines. The computing device is continuously connected to the base network.Mobile computing means that the computing device is not continuously connected to the base or central network. Mobile computing does not necessarily require wireless communication. It may not require communication between devices at all.Various techniques used for wireless and mobile computing are as follows:Global System for Mobile communications (GSM) — GSM uses narrowband TDMA (Time Division Multiple Access), which allows eight simultaneous calls on the same radio frequency. GSM users simply switch subscriber identification module (SIM) cards to access a particular wireless service provider.Code-Division Multiple Access (CDMA) — It uses a spread-spectrum technique where data is sent in small pieces over a number of discrete frequencies. Each user's signal is spread over the entire bandwidth by unique spreading code. At the receiver end, the same unique code is used to recover the signal.Wireless in Local Loop (WLL) — WLL is a system that connects subscribers to the public switched telephone network (PSTN) using radio signals as a substitute for other connecting media.General Packet Radio Service (GPRS) — It is a technology for radio transmission of small packets of data especially between mobile devices and Internet.First Generation (1G) — 1G networks were conceived and designed purely for voice calls with almost no consideration of data services.Second Generation (2G) — They offered improved sound quality, better security and higher total capacity.Third Generation (3G) — 3G mobile communications technology is a broad­ band, packet-based transmission of text, digitized voice, video, and multimedia at data rates up to and possibly higher than 2 megabits per second (Mbps), offering a consistent set of services to mobile computer and phone users no matter where they are located in the world.Fourth Generation (4G) — 4G is a Mobile multimedia, Network System with anytime anywhere Global mobility support, integrated wireless solution, and Customized Personal Service.Fifth Generation (5G) — 5G networks promise to provide speeds of upto 100 gigabits per second. 5G is set to be 40 to 100 times faster than 4G networks.

Question 7

Question 4Define network security. What is its need ? How can it be achieved ?

Accepted Answer

Network security refers to making sure that only legal or authorized users and programs gain access to information resources like databases. Also, certain control mechanisms are setup to ensure that properly authenticated users get access only to those resources that they are entitled to use.Network security is very important because data travels through a network. Protection of data and its secure transmission is only possible if methods are employed to secure the network from various threats like physical/software security holes, inconsistent usage holes, hacking, cracking, etc.Network security can be achieved through the following protective measures:Authorization — It determines if the service requestor is entitled to perform the desired operation. It is performed by asking the user a legal login-id. If the user is able to provide a legal login-id, he/she is considered an authorized user.Authentication — It involves accepting credentials from the entity and validating them against an authority. The authorized user is asked to provide a valid password, and if he/she is able to do this, he/she is considered to be an authentic user.Encrypted Smart Cards — It is a hand-held smart card that can generate a token that a computer system can recognise. Every time a new and different token is generated, which even-though cracked or hacked, can not be used later.Biometric Systems — It involves some unique aspect of a person's body such as finger-prints, retinal patterns etc. to establish his/her identity.Firewall — It is a system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented in both hardware and software, or a combination of both. There are several types of firewall techniques such as packet filter, application filter, proxy server and circuit level gateway.

Question 8

Question 5"New York Avenue" is planning to expand their network in India, starting with two cities in India to provide infrastructure for distribution of their canned products. The company has planned to set up their main offices in Ahmedabad, at three different locations and have named their offices as "Work Office", "Factory" and "Back Office". The company has its Corporate Unit in Delhi. A rough layout of the same is as shown below:Approximate distance between these offices is as follows :FromToDistanceWork OfficeBack Office110 mWork OfficeFactory14 kmWork OfficeCorporate Office1280 kmBack OfficeFactory13 kmIn continuation of the above, the company experts have planned to install the following number of computers in each of their offices :Work Office200Back Office115Factory67Corporate75(i) Suggest the kind of network required (out of LAN, MAN, WAN) for connecting each of the following offices:Work Office and FactoryWork Office and Back Office(ii) Which one of the following devices will you suggest for connecting all the computers within each of their office units ?Switch/HubModemTelephone(iii) Which of the following communication media, you will suggest to be procured by the company for connecting their local offices in Ahmedabad for very effective (High Speed) communication ?Telephone CableOptical FibreEthernet Cable(iv) Suggest a cable/wiring layout for connecting the company's local office units located in Ahmedabad. Also, suggest an effective method/technology for connecting the company's office unit located in Delhi.(v) Which one of the following devices will you suggest for connecting all the computers within each of their offices ?Switch/HubModemTelephone

Accepted Answer

(i) The kind of network required are:MAN should be used as the distance between the work office and factory is 14 km, which is greater than the geographical extent of LAN.LAN can be used as the distance between the Work Office and Back Office is less than 1 km.(ii) Switch/Hub(iii) Optical Fibre(iv) Wiring layout for connecting the company's local office units located in Ahmedabad is shown below:Work office - Factory - Back officeAn effective method/technology for connecting the company's office unit located in Delhi is through satellite.(v) Switch/Hub

Question 9

Question 7"China Middleton Fashion" is planning to expand their network in India, starting with two cities in India to provide infrastructure for distribution of their product. The company has planned to setup their main office in Chennai at three different locations and have named their offices as "Production Unit", "Finance Unit" and "Media Unit". The company has its corporate unit in Delhi. A rough layout of the same is shown on the right :Approximate distance between these Units is as follows :FromToDistanceProduction UnitFinance Unit70 mProduction UnitMedia Unit15 kmProduction UnitCorporate Unit2112 kmFinance UnitMedia Unit15 kmIn continuation of the above, the company experts have planned to install the following number of computers in each of their offices :Production Unit150Finance Unit35Media Unit10Corporate Unit30(i) Suggest the kind of network required (out of LAN, MAN, WAN) for connecting each of the following office units :Production Unit and Media UnitProduction Unit and Finance Unit(ii) Which one of the following devices will you suggest for connecting all the computers within each of their office units ?Switch/HubModemTelephone(iii) Which of the following communication media, you will suggest to be procured by the company for connecting their local office units in Chennai for very effective (High Speed) communication ?Telephone CableOptical FibreEthernet Cable(iv) Suggest a cable/wiring layout for connecting the company's local office units located in Chennai. Also, suggest an effective method/technology for connecting the company's office unit located in Delhi.

Accepted Answer

(i) The network used to connect :Production Unit and Media Unit is MAN as the distance is about 15 km.Production Unit and Finance Unit is LAN as the distance is less than 1 km.(ii) Switch/Hub(iii) Optical Fibre(iv) Two possible cable/wiring layouts for connecting the company's local office units located in Chennai are given below:Production Unit - Finance Unit - Media UnitMedia Unit - Production Unit - Finance UnitSatellite links can be established for connecting the company's office unit located in Delhi.

Question 10

Question 12Expertia Professional Global (EPG) is an online corporate training provider company for IT related courses. The company is setting up their new campus in Mumbai. You as a network expert have to study the physical locations of various buildings and the number of computers to be installed. In the planning phase, provide the best possible answers for the queries (i) to (iv) raised by them.Building to Building Distance (in m) :FromToDistanceAdmin. BuildingFinance Building60Admin. BuildingFaculty Studio Building120Finance BuildingFaculty Studio Building70Computers to be Installed in each Building :BuildingsComputersAdmin. Building20Finance Building40Faculty Studio Building120(i) Suggest the most appropriate building, where EPG should plan to install the server.(ii) Suggest the most appropriate building cable layout to connect all three buildings for efficient communication.(iii) Which type of network out of the following is formed by connecting the computers of the buildings?LANMANWAN(iv) Which wireless channel out of the following should be opted by EPG to connect to students of all over the world ?InfraredMicrowaveSatellite

Accepted Answer

(i) EPG should install the server in Faculty Studio Building as it houses the maximum number of computers. Thus, it will reduce cable cost and keep maximum traffic local.(ii) The most appropriate building cable layout to connect all three buildings for efficient communication is given below:Administrative Building - Finance Building - Faculty Studio Building(iii) LAN network is formed as the distance between the three buildings is less than 1 km.(iv) Satellite communication should be opted by EPG to connect to students of all over the world.

Question 11

Question 16The difference between IMAP and POP protocols:IMAP allows to download emails once the user accesses the email account while POP doesn'tPOP allows to download emails once the user accesses the email account while IMAP doesn'tBoth protocols allow to downloadBoth protocols don't allow to download

Accepted Answer

POP allows to download emails once the user accesses the email account while IMAP doesn'tReason — In the POP (Post Office Protocol) protocol, all email messages are downloaded from the mail server to the user's local computer. On the other hand, in the IMAP (Internet Message Access Protocol) protocol, email messages are stored on the server, and only when the user requests to read a specific email message, it is downloaded from the server to the user's device.

Question 12

Question 26Which protocol holds the email only until you receive it?SMTPFTPIMAPPOP3

Accepted Answer

POP3Reason — POP3 (Post Office Protocol 3) holds the email until the user actually receives/downloads the email.

Source: This question is from Computer Networks - II, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Computer Networks - II: Question, Protocol, Holds, Email, Until, Receive. These are fundamental topics in Computer Science that students are expected to master as part of the CBSE Class 12 curriculum.A thorough understanding of these concepts will help you answer similar questions confidently in your CBSE examinations. These topics are frequently tested in both objective and subjective sections of Computer Science papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.
How to Approach MCQsMultiple choice questions test your ability to quickly recall facts and apply concepts. Read all options carefully before selecting your answer. Use the process of elimination to rule out clearly incorrect options first. If two options seem similar, look for the subtle difference that makes one more accurate. For numerical MCQs, verify your answer by substituting it back into the problem.
Key Points to RememberWrite programs with proper indentation and comments.
Trace through your code with sample inputs to verify correctness.
Explain the logic behind each step of your solution.
Familiarise yourself with common library functions and methods.
Related Questions from Computer Networks - IIQ1: Question 1 Discuss various Network devices.
Q10: Question 6(ii) Write short note on TCP/IP.
Q11: Question 9 Discuss the two technologies to connect to Internet wirelessly.
Q12: Question 12 Expertia Professional Global (EPG) is an online corporate training provider company for...
Q13: Question 5 What is the purpose of using a repeater in context of networking ?
Practice more questions from Computer Networks - II &mdash; Computer Science, Class 12 CBSE

Question 13

Question 29Which of the following is not a mobile communication technology ?GPRSGSM5GHTTP

Accepted Answer

HTTPReason — HTTP (Hypertext Transfer Protocol) is the set of rules for transferring hypertext on WWW (World Wide Web). On the other hand, GPRS (General Packet Radio Service), GSM (Global System for Mobile), and 5G are all mobile communication technologies.

Question 14

Question 33The new web standard that incorporates AI, ML and blockchain to the Internet is ...............Web 1.0Web 2.0Web 3.0Web 4.0

Accepted Answer

Web 3.0Reason — Web 3.0 aims at combining new technologies like artificial intelligence (AI), machine learning (ML), and blockchain etc. so as to power intelligent apps over the internet.

Question 15

Question 34A security mechanism that can be created in hardware and software both to prevent the unauthorised access to and from a network is called ...............Anti-virusNetwork securityAuthenticationFirewall

Accepted Answer

FirewallReason — A system designed to prevent unauthorized access to or from a private network is called Firewall. Firewalls can be implemented in both hardware and software, or a combination of both.

Question 16

Question 39............... is a communication methodology designed to deliver both voice and multimedia communications over Internet protocol.VoIPSMTPPPPHTTP

Accepted Answer

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

Source: This question is from Computer Networks - II, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Computer Networks - II: Question, Communication, Methodology, Designed, Deliver, Voice. These are fundamental topics in Computer Science that students are expected to master as part of the CBSE Class 12 curriculum.A thorough understanding of these concepts will help you answer similar questions confidently in your CBSE examinations. These topics are frequently tested in both objective and subjective sections of Computer Science papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.
How to Approach MCQsMultiple choice questions test your ability to quickly recall facts and apply concepts. Read all options carefully before selecting your answer. Use the process of elimination to rule out clearly incorrect options first. If two options seem similar, look for the subtle difference that makes one more accurate. For numerical MCQs, verify your answer by substituting it back into the problem.
Key Points to RememberWrite programs with proper indentation and comments.
Trace through your code with sample inputs to verify correctness.
Explain the logic behind each step of your solution.
Familiarise yourself with common library functions and methods.
Related Questions from Computer Networks - IIQ1: Question 1 Discuss various Network devices.
Q10: Question 6(ii) Write short note on TCP/IP.
Q11: Question 9 Discuss the two technologies to connect to Internet wirelessly.
Q12: Question 12 Expertia Professional Global (EPG) is an online corporate training provider company for...
Q13: Question 5 What is the purpose of using a repeater in context of networking ?
Practice more questions from Computer Networks - II &mdash; Computer Science, Class 12 CBSE

Question 17

Question 5What is a communication protocol ? What is its role in a network ?

Accepted Answer

A communication protocol is a formal description of message formats and the rules that two or more machines must follow to exchange those messages.The reason that the Internet works at all is that every computer connected to it uses the same set of rules for communication. The communication protocol used by Internet is TCP/IP.The TCP or Transmission Control Protocol is responsible for dividing the­ file/message into packets on the source computer. It is also responsible for reassembling the received packets at the destination or recipient computer.The IP or Internet Protocol is responsible for handling the address of destination computer so that each packet is routed (sent) to its proper destination.

Question 18

Question 6(i)Write short note on HTTP.

Accepted Answer

HTTP (Hypertext Transfer Protocol) is the set ot rules for transferring hypertext, like text, graphic, image, sound, video etc., on World Wide Web.It is an application-level protocol with the lightness and speed necessary for distributed, collaborative, hypermedia information systems. It is a generic, stateless, object-oriented protocol. A feature of HTTP is the typing of data representation, allowing systems to be built independently of the data being transferred.HTTP is also used as a generic protocol for communication between user agents and proxies/gateways to other Internet protocols. The HTTP protocol consists of two fairly distinct items : the set of requests from browsers to servers and the set of responses going back to the other way.

Question 19

Question 6(ii)Write short note on TCP/IP.

Accepted Answer

TCP/IP is the base communication protocol of the Internet. IP part of TCP/IP uses numeric IP addresses to join network segments and TCP part of TCP/IP provides reliable delivery of messages between networked computers.TCP is responsible for making sure that the commands get through to the other end. It keeps track of what is sent, and retransmits anything that did not get through.TCP/IP applications use the following four layers:an application protocol (such as mail)a protocol such as TCP that provides services need by many applicationsIP, which provides the basic service of getting datagrams to their destinationthe protocols needed to manage a specific physical medium, such as Ethernet or a point to point line.

Question 20

Question 9What is the use of TELNET ?

Accepted Answer

Telnet enables users to remotely access computer systems. Essentially, a Telnet program provides a character-based terminal window on another system. Upon connection, users receive a login prompt on that system. If access is permitted, users can operate on that system, much like they would if physically present next to it.

Computer Networks - II

Assertions And Reasons

Checkpoint 111

Checkpoint 112

Long Answer Questions

Multiple Choice Questions

Short Answer Questions