Question 1

Question 1Internet is a network of networks. How did it come into existence ? How does it function ?

Accepted Answer

The seeds of today's Internet were planted in 1969, when U.S. Department of Defense sponsored a project named ARPANET (Advanced Research Projects Agency NETwork). The goal of this project was to connect computers at different universities and U.S. defense. Soon the engineers, scientists, students and researchers, who were part of this system, began exchanging data and messages on it. The use­rs of this system were also able to play long distance games and socialize with people who shared their interests. ARPANET started with a handful of computers but it expanded rapidly.In mid 80's, another federal agency, the National Science Foundation, created a new, high-capacity network called NSFnet, which was more capable than ARPANET. NSFnet allowed only the academic research on its network and not any kind of private business­ on it. So many private companies built their own networks, which were later interconnected along with ARPANET and NSFnet to form Internet.It was the Inter networking i.e., the linking of these two and some other networks that was named Internet. The original ARPANET was shut down in 1990, and the government funding for NSF discontinued in 1995. But the commercial Internet services came into picture, which are running the Internet.The Internet is a world-wide network of computer networks. In Internet, most computers are not connected directly to the Internet. Rather they are connected to smaller networks, which in turn are connected through gateways to the Internet backbone.The Internet functions in the following way:At the source computer, the message or the file/document to be sent to another computer is firstly divided into very small parts called packets. A packet generally contains some information.Each packet is given a number serialwise e.g., 1, 2, 3.All these packets are then sent to the address of destination computer.The destination computer receives the packets in random manner. If a packet is garbled or lost, it is demanded again.The packets are reassembled in the order of their number and the original message/file/document is obtained.

Question 2

Question 2Discuss various types of networks. Can you imagine the relationship of a LAN with a WAN ? What is it ? Discuss.

Accepted Answer

Based on geographical spread, networks can be of four types:LAN (Local Area Network) —	Small computer networks that are confined to a localised area such as a building or­ factory, are known as Local Area Networks (LANs). LANs have geographical spread of upto 1 km.WAN (Wide Area Network) — The networks spread across countries or on a very big geographical area are known as WANs. The WANs link computers to facilitate fast and efficient exchange of information at lesser costs and higher speeds. The largest WAN in existence is the Internet.PAN (Personal Area Network) — It is the interconnection of information technology devices within the­ range of an individual person, typically within a range of 10 meters. PAN could also be interconnected without wires to the Internet or other networks.MAN (Metropolitan Area Network) — MAN refers to a network that is spread over an area as big as a city.Based on component roles, network can be of two types:Peer-to-Peer networks — Computers in peer-to-peer network can act as both servers sharing resources and as clients using the resources. A peer-to-peer network has upto ten computers.Client/Server Networks — Server-based networks provide centralized control of network resources and rely on server computers to provide security and network administration. A client computer requests and utilizes network resources and a server is dedicated to processing client requests. Bigger networks prefer to have this type of network with centralized control.LAN or Local Area Network refers to small computer networks that are confined to a localised area of upto 1 km. WAN or Wide Area Network refers to networks spread across countries or on a very big geographical area.A Wide Area Network (WAN) can be a group of LANs that are spread across several locations and connected together to look like one big LAN. The WANs link computers to facilitate fast and efficient exchange of information at lesser costs and higher speeds.

Question 3

Question 3What is switching ? Discuss various switching technologies.

Accepted Answer

The technique by which nodes of a network transmit data to other nodes, is known as switching technique.The three switching techniques are as follows:Circuit switching — A complete physical connection is established between the sender and the receiver and then data are transmitted from the source computer to the destination computer. A local telephone network is an example of a circuit-switched network.Message switching — In this technique, the source computer sends message to the switching office first, which stores the data in its buffer. It then looks for a free link to another switching office and then sends the data to this office. This process is continued until the data are delivered to the destination computers. This working principle is known as store and forward i.e., store first, forward later, one jump at a time. Here full messages travel across different intermediate hops.Packet switching — A fixed size of packet which can be transmitted across the network is specified. The message is divided into packets and packets travel across hops.

Question 4

Question 4What is communication media ? Discuss different types of communication media used in networks.

Accepted Answer

Communication media refer to the ways, means or channels of transmitting message from sender to the receiver.Communication media can be grouped in two categories:Guided media — These media include cables. There are three basic types of cables :Twisted-Pair Cables — These cables consist of two identical wires wrapped together in a double helix. These are also used for short and medium range telephone communication. The two types of twisted pair cables are Unshielded twisted pair cable (UTP) and Shielded twisted pair cable (STP).Coaxial Cables — This type of cable consists of a solid wire core surrounded by one or more foil or wire shields, each separated by some kind of plastic insulator. The inner core carries the signal, and the shield provides the ground. It is suitable for high speed communication. It is widely used for television signals. The two types of coaxial cables are thicknet and thinnet coaxial cable.Fiber-optic Cables — Optical fibres consist of thin strands of glass or glass like material which are so constructed that they carry light from a source at one end of the fiber to a detector at the other end. The fiber consists of core, cladding, protective coating. The bandwidth of the medium is very high. The two types of optical fibres are single mode and multimode fiber cables.Unguided media — These media include waves through air, water or vacuum.Unguided communication media are as follows:Microwaves — The microwaves are similar to radio and television signals and are used for long distance communication. Microwave transmission consists of a transmitter, receiver and the atmosphere. The microwave transmission is line-of-sight transmission.Radiowaves — The transmission making use of radio frequencies is termed as radio-wave transmission. This transmission includes transmitter, receiver and antenna.Satellites — Satellite communication use the synchronous satellite to relay the radio signal transmitted from ground station. This transmission includes transponders.

Question 5

Question 5Discuss various Guided media.

Accepted Answer

Guided media include cables. There are three basic types of cables :Twisted-Pair Cables — These cables consist of two identical wires wrapped together in a double helix. These are also used for short and medium range telephone communication. The two types of twisted pair cables are Unshielded twisted pair cable (UTP) and Shielded twisted pair cable (STP).Coaxial Cables — This type of cable consists of a solid wire core surrounded by one or more foil or wire shields, each separated by some kind of plastic insulator. The inner core carries the signal, and the shield provides the ground. It is suitable for high speed communication. It is widely used for television signals. The two types of coaxial cables are thicknet and thinnet coaxial cable.Fiber-optic Cables — Optical fibres consist of thin strands of glass or glass like material which are so constructed that they carry light from a source at one end of the fiber to a detector at the other end. The fiber consists of core, cladding, protective coating. The bandwidth of the medium is very high. The two types of optical fibres are single mode and multimode fiber cables.

Question 6

Question 6Discuss various Unguided media.

Accepted Answer

Unguided media include waves through air, water or vacuum. Unguided communication media are as follows:Microwaves — The microwaves are similar to radio and television signals and are used for long distance communication. Microwave transmission consists of a transmitter, receiver and the atmosphere. The microwave transmission is line-of-sight transmission.Radiowaves — The transmission making use of radio frequencies is termed as radio-wave transmission. This transmission includes transmitter, receiver and antenna.Satellites — Satellite communication use the synchronous satellite to relay the radio signal transmitted from ground station. This transmission includes transponders.

Question 7

Question 7What are different types of networks based on roles of computers ?

Accepted Answer

The different types of networks based on roles of computers are as follows :Peer-to-Peer networks — Computers in peer-to-peer network can act as both servers sharing resources and as clients using the resources. A peer-to-peer network has upto ten computers.Client/Server Networks — Server-based networks provide centralized control of network resources and rely on server computers to provide security and network administration. A client computer requests and utilizes network resources and a server is dedicated to processing client requests. Bigger networks prefer to have this type of network with centralized control.

Question 8

Question 8What are different types of networks based on geographical spread ?

Accepted Answer

The different types of networks based on geographical spread are as follows :LAN (Local Area Network) —	Small computer networks that are confined to a localised area such as a building or­ factory, are known as Local Area Networks (LANs). LANs have geographical spread of upto 1 km.WAN (Wide Area Network) — The networks spread across countries or on a very big geographical area are known as WANs. The WANs link computers to facilitate fast and efficient exchange of information at lesser costs and higher speeds. The largest WAN in existence is the Internet.PAN (Personal Area Network) — It is the interconnection of information technology devices within the­ range of an individual person, typically within a range of 10 meters. PAN could also be interconnected without wires to the Internet or other networks.MAN (Metropolitan Area Network) — MAN refers to a network that is spread over an area as big as a city.

Question 9

Question 9What are topologies ? Why are they important ? Discuss different topologies and advantages/disadvantages they offer.

Accepted Answer

The patterns of interconnection of nodes in a network are called Topologies. Topology is important as it affects the choice of media and the access method used.The types of topologies are as follows:Star Topology — This topology consists of a central node to which all other nodes are connected by a single path.Advantages are :It provide easy access for service.Access protocols are very simple in star topology.There is a centralized control/problem diagnosis.Failure of single connection involves disconnecting only that node without affecting network.Disadvantages are :It requires long cable length.It is difficult to expand.There is a central node dependency.Bus or Linear topology — This topology consists of a single length of the transmission medium onto which the various nodes are attached. Transmission from any station travels the length of the bus in both directions and can be received by all other stations. The destination device, on identifying the address on data packet copies the data onto its disk. When the data packet reaches at either end the terminator on that end absorbs the signal, removing it from the bus.Advantages :It requires short cable length and simple wiring layout.It provides resilient architecture.This topology can be expanded easily.Disadvantages :Fault diagnosis is difficult in this topology.Fault isolation is difficult in bus topology.Repeater configuration is necessary.Nodes must be intelligent in bus topology.Tree Topology — This topology is combination of bus and star topologies. The shape of the network is that of an inverted tree with the central root branching and sub-branching to the extremities of the network. Transmission in this topology takes place in the same way as in bus topology.Advantages :It uses point-to-point wiring for individual segments.It is supported by several hardware and software vendors.It is flexible and scalable.Disadvantages :Overall length of each segment is limited by the type of cabling used.If the backbone line breaks, the entire segment goes down.It is more difficult to configure and wire than other topologies.Ring or Circular Topology — In this topology, each node is connected to two and only two neighbouring nodes. Thus data travels in one direction only, from node to node around the ring. After passing through each node, it returns to the sending node, which removes it.Advantages :The chances of data collisions are low due to unidirectional flow of data.They are simple to design and implement.Disadvantages :Node failure breaks the ring and communication stops.Difficulty in troubleshooting.Mesh topology — In this topology, each node is connected to more than one node to provide an alternative route in the case the host is either down or too busy.Advantages :It provides extensive back-up and rerouting capabilities.Each node is connected to more than one node to provide an alternative route in the case the host is either down or too busy.Disadvantages :Mesh networks can be complex to design, implement, and manage, especially as the number of nodes increases.Maintenance and troubleshooting in mesh networks can be challenging due to their decentralized nature.Fully Connected topology — When in a network, there is a direct link between each host, then the network is said to be fully connected. This characteristic is termed as full connectivity.Advantages :Data travels quickly because devices are directly connected to each other.If one connection fails, there are other paths for communication to continue, making the network robust.Disadvantages :Managing all the connections can be complicated.Setting up and maintaining a fully connected network can be expensive.

Question 10

Question 10Write a note on the functioning of the Internet.

Accepted Answer

In Internet, most computers are not connected directly to the Internet. Rather they are connected to smaller networks, which in turn are connected through gateways to the Internet backbone.Internet functions in the following manner:At the source computer, the message or the file/document to be sent to another computer is firstly divided into very small parts called packets.Each packet is given a number serial wise e.g., 1, 2, 3.All these packets are then sent to the address of destination computer.The destination computer receives the packets in random manner. If a packet is garbled or lost, it is demanded again.The packets are reassembled in the order of their number and the original message/file/document is obtained.Every computer connected to the Internet uses communication protocols — Transmission Control Protocol(TCP) and Internet Protocol (IP).

Question 11

Question 16A local telephone network is an example of a ............... network.Packet switchedCircuit switchedMessage switchedAll of these

Accepted Answer

Circuit switchedReason — When we make a telephone call, the switching equipment within the telephone system seeks out a physical copper path all the way from the sender's telephone to the receiver's telephone. Hence, an end-to-end path is set up before any data can be sent. Therefore, a local telephone network is an example of a circuit-switched network.

Question 12

Question 17Which transmission media is capable of having a much higher bandwidth (data capacity) ?CoaxialTwisted pair cableUntwisted cableFibre optic

Accepted Answer

Fibre opticReason — Optical fibers consist of thin strands of glass which are so constructed that they carry light from a source at one end of the fiber to a detector at the other end. Thus, the bandwidth of the medium is potentially very high.

Question 13

Question 24Which of the following is not a guided medium ?twisted-pair cablecoaxial cablefiber-optic cableRadio-waves

Accepted Answer

Radio-wavesReason — Radio waves are unguided medium as they are waves through the air.

Source: This question is from Computer Networks - I, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Computer Networks - I: Question, Guided, Medium, Twisted, Pair, Cable. 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 - IQ1: Question 1 Internet is a network of networks. How did it come into existence ? How does it function...
Q10: Question 10 Write a note on the functioning of the Internet.
Q11: Question 10(ii) Write some advantages and disadvantages of coaxial cables.
Q12: Question 10(iii) Write some advantages and disadvantages of twisted pair cables.
Q13: Question 10(iv) Write some advantages and disadvantages of radio waves.
Practice more questions from Computer Networks - I &mdash; Computer Science, Class 12 CBSE

Question 14

Question 25Radio-waves, microwaves and infrared waves are types ofwireless transmissionguided transmissionwired transmissionunguided transmission

Accepted Answer

wireless transmissionunguided transmissionReason — Radio waves, microwaves, and infrared waves are types of wireless transmission, also known as unguided transmission, because they propagate through the air or vacuum as waves.

Question 15

Question 26Twisted-pair, Coaxial and Fiber optic are types ofwireless transmissionguided transmissionwired transmissionunguided transmission

Accepted Answer

guided transmissionwired transmissionReason — Twisted-pair, coaxial, and fiber optic are types of wired transmission, also known as guided transmission, because they utilize cables.

Question 16

Question 32Which of the following devices can be used at the centre of a star topology?RouterRepeaterModemHub

Accepted Answer

HubReason — A hub can be used at the centre of a star topology as it has multiple ports that are used for connecting multiple computers.

Source: This question is from Computer Networks - I, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Computer Networks - I: Question, Devices, Centre, Star, Topology, Router. 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 - IQ1: Question 1 Internet is a network of networks. How did it come into existence ? How does it function...
Q10: Question 10 Write a note on the functioning of the Internet.
Q11: Question 10(ii) Write some advantages and disadvantages of coaxial cables.
Q12: Question 10(iii) Write some advantages and disadvantages of twisted pair cables.
Q13: Question 10(iv) Write some advantages and disadvantages of radio waves.
Practice more questions from Computer Networks - I &mdash; Computer Science, Class 12 CBSE

Question 17

Question 33If a computer connected to a star topology fails, the entire network will ...............also failwork unaffectedlyonly server will worknone of these

Accepted Answer

work unaffectedlyReason — Star topology consists of a central node to which all other nodes are connected by a single path. Thus, failure of a single connection typically involves disconnection of one node from an otherwise fully functional network.

Question 18

Question 34A combination of bus and star topologies is called a ............... topology.CombinationHybridMeshTree

Accepted Answer

TreeReason — 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.

Source: This question is from Computer Networks - I, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Computer Networks - I: Question, Combination, Bus, Star, Topologies, Topology. 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 - IQ1: Question 1 Internet is a network of networks. How did it come into existence ? How does it function...
Q10: Question 10 Write a note on the functioning of the Internet.
Q11: Question 10(ii) Write some advantages and disadvantages of coaxial cables.
Q12: Question 10(iii) Write some advantages and disadvantages of twisted pair cables.
Q13: Question 10(iv) Write some advantages and disadvantages of radio waves.
Practice more questions from Computer Networks - I &mdash; Computer Science, Class 12 CBSE

Question 19

Question 35Internet is an example of ............... topology.StarBusBustarBus

Accepted Answer

BusReason — The internet operates on a bus topology where data flows through interconnected networks via a central backbone network.

Source: This question is from Computer Networks - I, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Computer Networks - I: Question, Internet, Topology, Star, Bus, Bustar. 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 - IQ1: Question 1 Internet is a network of networks. How did it come into existence ? How does it function...
Q10: Question 10 Write a note on the functioning of the Internet.
Q11: Question 10(ii) Write some advantages and disadvantages of coaxial cables.
Q12: Question 10(iii) Write some advantages and disadvantages of twisted pair cables.
Q13: Question 10(iv) Write some advantages and disadvantages of radio waves.
Practice more questions from Computer Networks - I &mdash; Computer Science, Class 12 CBSE

Question 20

Question 36Which type of network needs 'terminators' to function correctly ?BusRingStarMesh

Accepted Answer

BusReason — Bus topology requires terminators at either end, which absorb the signal, to function correctly.

Source: This question is from Computer Networks - I, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter Computer Networks - I: Question, Network, Needs, Terminators, Correctly, Bus. 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 - IQ1: Question 1 Internet is a network of networks. How did it come into existence ? How does it function...
Q10: Question 10 Write a note on the functioning of the Internet.
Q11: Question 10(ii) Write some advantages and disadvantages of coaxial cables.
Q12: Question 10(iii) Write some advantages and disadvantages of twisted pair cables.
Q13: Question 10(iv) Write some advantages and disadvantages of radio waves.
Practice more questions from Computer Networks - I &mdash; Computer Science, Class 12 CBSE

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