Question 1

Question 1Assertion. There is a difference between a standalone computer and a computer as a network node.Reason. A standalone computer needs a special hardware NIC to be a network node.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both Assertion and Reason are true and Reason is the correct explanation of Assertion.ExplanationA standalone computer operates independently without being connected to a network, while a computer serving as a network node participates in network communication. To function as a network node, a computer requires a Network Interface Card (NIC) hardware, which facilitates communication over the network.

Question 2

Question 2Assertion. A server is a computer but not every computer is a server.Reason. A computer having the capabilities to serve the requests of other network nodes is a server.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both Assertion and Reason are true and Reason is the correct explanation of Assertion.ExplanationA computer becomes a server when it possesses the capability to fulfill requests from other network nodes. This aligns with the definition of a server. Therefore, a server is a computer, but not all computers serve the same purpose.

Question 3

Question 3Assertion. On a computer network the users work on network nodes only.Reason. A server cannot act as a network node.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Assertion is true but Reason is false.ExplanationUsers on a computer network interact with various network nodes such as computers, printers, switches, routers, etc., to access resources or services. In a computer network, a server is indeed considered a network node. A network node is any device connected to a network that can communicate with other devices. Servers, which provide services or resources to other devices on the network, are an integral part of network infrastructure and are thus considered network nodes.

Question 4

Question 4Assertion. The tree topology is a hybrid topology created through a combination of Bus and Star topologies.Reason. In tree topologies, at a time either bus topology transmission is followed or star topology transmission takes place but never both.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Assertion is true but Reason is false.ExplanationThe tree topology is a hybrid topology created through a combination of Bus and Star topologies. In tree topology, transmission takes place in the same way as in the bus topology.

Question 5

Question 5Assertion. The bus and star topologies are widely used topologies.Reason. Bus topology is the simplest topology and star topology is more robust comparatively.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both Assertion and Reason are true and Reason is the correct explanation of Assertion.ExplanationBoth the bus and star topologies are widely used in networking. The bus topology requires short cables and features a simple wiring layout. It provides a resilient architecture, which enhances hardware reliability. Therefore, the bus topology is considered as the simplest network topologies. While the star topology is known for its robustness, as it provides easy access for service and better fault tolerance compared to other topologies.

Question 6

Question 6Assertion. MODEM stands for modulator-demodulator.Reason. It is a computer hardware device that converts data from a digital format to analog and vice versa.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both A and R are true and R is the correct explanation of A.ExplanationMODEM stands for modulator-demodulator. It is a computer hardware device that allows connecting and communicating with other computers via telephone lines. It converts digital data from a computer into analog signals suitable for transmission over telephone lines, and vice versa, converting incoming analog signals back into digital data that the computer can understand.

Question 7

Question 7Assertion. A modem is a communication device that works on the principle of converting digital data to analog data and vice versa.Reason. Modulation is a process of converting digital data to analog form and Demodulation is a process of converting analog data to digital form.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both Assertion and Reason are true and Reason is the correct explanation of Assertion.ExplanationModem is a communication device that works on the process of modulation/demodulation. In modulation, digital data of the sender computer is converted in analog form to travel over the telephone lines to the target computer. In demodulation, received analog data is converted back to digital form for the target computer.

Question 8

Question 8Assertion. A hub can also act as an amplifier at times.Reason. An active hub is capable of amplifying the signal during transmission while a passive hub merely lets the signal pass through it.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both Assertion and Reason are true and Reason is the correct explanation of Assertion.ExplanationA hub can also act as an amplifier at times. Hubs can function as either passive or active devices. Active hubs electrically amplify the signal as it moves from one connected device to another. While passive hubs allow the signal to pass from one computer to another without any change.

Question 9

Question 9Assertion. A repeater is not like an amplifier.Reason. A repeater regenerates a signal thereby removing noise.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Both Assertion and Reason are true and Reason is the correct explanation of Assertion.ExplanationA repeater is not like an amplifier because a repeater not only amplifies the signal but also performs signal regeneration. When a signal weakens over long distances, the repeater collects the inbound packet and then retransmits it as if it were originating from the source station. This process effectively removes noise.

Question 10

Question 10Assertion. A router and a bridge are similar.Reason. A router works like a bridge but can handle different protocols unlike bridge.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

Assertion is false but Reason is true.ExplanationA router is a network device that forwards data from one network to another using logical addresses. A router works like a bridge but can handle different protocols. On the other hand, a bridge is a device that links two networks together using physical addresses and can handle networks that follow the same protocols. Hence, a router and a bridge are different.

Question 11

Question 11Assertion. Hubs and switches can be replaced.Reason. While a hub is a broadcast device, a switch is a unicast device.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

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 12

Question 1Write two advantages and disadvantages of networks.

Accepted Answer

Two advantages of networks are:It allows sharing of resources like printers, scanners.It allows sharing of storage i.e., files can be shared over a network.Two disadvantages of networks are:If networks are badly managed, services can become unusable and productivity falls.If software and files are held centrally, it may be impossible to carry out any work if the central server fails.

Question 13

Question 2What is meant by topology ? Name some popular topologies.

Accepted Answer

The pattern of interconnection of nodes in a network is called the Topology.The most popular topologies are as follows:Bus or Linear topologyRing	or Circular topologyStar topologyTree topologyMesh topologyFully connected topology

Question 14

Question 3What are the factors that must be considered before making a choice for the topology ?

Accepted Answer

The factors that must be considered before making a choice for the topology are as follows:Cruciality of Work — How crucial the continuity of work is a very important factor. For instance, military networks must not fail at any cost thus fully connected topology is preferred for military networks.Cost — Keeping in mind the budget, we should decide about a topology. A linear bus topology network may be the least expensive way to install a network. Fully connected is the most expensive way of creating a network.Length of cable needed — Sometimes, length of cable must be saved. The linear bus topology network uses shorter lengths of cable.Future growth — If a network has to grow in future, then the topology must support expansion. With a star topology, expanding a network is easily done by adding another concentrator.Communication Media — Sometimes, difficult terrains like hilly areas do not allow use of regular cables. For such conditions, linear bus topologies are not possible. The most common cable in schools is unshielded twisted pair, which is most often used with star topologies.

Question 15

Question 4What are the similarities and differences between bus and tree topologies ?

Accepted Answer

SimilaritiesTransmission can be done in both the directions, and can be received by all other stations.There is no need to remove packets from the medium.DifferencesTree topology is a network with the shape of an inverted tree with the central root branching and sub-branching to the extremities of the network whereas in bus topology, all devices on network are connected to a single continuous cable called a bus.Tree topology is expensive and difficult to maintain as compared to Bus Topology.

Question 16

Question 5How is a PAN different from a LAN ?

Accepted Answer

LANPANLAN stands for Local Area Network.PAN stands for personal area network.LAN covers an area of up to 1 kilometer.PAN operates within a range of around 10 meters.LANs use wired (Ethernet, fiber optics) or wireless (Wifi) connections.PANs use wireless technologies like Bluetooth, Wifi.LAN networks are used to share data, information, programs, printers, hard-disks, modems etc.PAN networks are used to transfer files including email and calendar appointments, digital photos and music etc from phones and tablets to PC and vice versa.LANs provide connectivity within an organization or building.PAN is used to provide connectivity to an individual.

Question 17

Question 6What is NIC ?

Accepted Answer

NIC (Network Interface Card) is a network adapter that acts as an interface between computer and the network.

Question 18

Question 7(i)Give two advantages and two disadvantages of Star topology.

Accepted Answer

The two advantages of star topology are:Ease of service: The star topology has a number of concentration points (where connections are joined). These provide easy access for service or reconfiguration of the network.One device per connection: In star topology, failure of a single connection involves disconnecting one node from an otherwise fully functional network.The two disadvantages of star topology are:Long cable length: Because each node is directly connected to the center, the star topology necessitates a large quantity of cable.Central node dependency: If the central node in a star network fails, the entire network is rendered inoperable. This introduces heavy reliability and redundancy constraints on this node.

Question 19

Question 7(ii)Give two advantages and two disadvantages of tree topology.

Accepted Answer

Two advantages of tree topology are:It uses point-to-point wiring for individual segments.It is supported by several hardware and software vendors.Two disadvantages of tree topology are:Overall length of each segment is limited by the type of cabling used.If the backbone line breaks, the entire segment goes down.

Question 20

Question 7(iii)Give two advantages and two disadvantages of bus topology.

Accepted Answer

The two advantages of bus topology in a network are:It requires shorter cable length and has a simple wiring layout.It provides a resilient architecture making it very reliable from a hardware point of view.The two disadvantages of bus topology in a network are:Fault diagnosis and isolation is difficult.Reconfiguration is required when the network has its backbone extended using repeaters.

Introduction to Computer Networks

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