Answers [Networking and Telecommunication]

Chapter -1

Networking & Telecommunication

1)      What is communication?
Ans: Communication is sending and receiving information between two or more persons. It is derived from the Latin word ‘communicare’.

2)      What is telecommunication?
Ans: Telecommunication is a system of transmission of sounds, images, texts or data in the form of electronic signals.

3)      What is data communication?
Ans: Data communication system is the collection of hardware, software and other devices that allows to exchange data, information and voice between two or more devices through a wire or radio waves.

4)      Give any two examples of data communication.

Ans: Any two examples of data communication are:

           a)      E-mail

           b)      Chat

5)      Write down the components of data communication.
Ans: The components of data communication are:
i) Data         ii) Sender          iii) Medium        iv) Receiver      v) Protocol

6)      What is medium?
Ans: A path through which the sender makes communication to the receiver is known as medium.

7)      What is communication protocol?
Ans: A communication protocol is a set of rules by which computers on the network communicate with each other.

8)      List the function of protocol.

Ans: The functions of protocol are

a.       Connection control

b.       Helps to transfer data either in connectionless or connection oriented.

c.       Sequencing supports ordered delivery flow control and error control.

9)      Explain TCP/IP suite.

Ans: The protocol of internet is TCP/IP.

10)   What is data transmission mode?

Ans: Data transmission mode is the way of transmission of data from one location to another.

11)   Write down the modes of data transmission.
Ans: The modes of data transmission are:
i) Simplex mode        ii)Half duplex mode       iii) Full Duplex Mode

12)   Define simplex mode with example.
Ans: The transmission mode in which transmission of data can take place in one direction only is called simplex mode.
E.g.: Newspaper, Radio and Television.

13)   Define half duplex mode with example.
Ans: The transmission mode in which transmission of data can take place in both directions but only in one direction at a time is called half duplex mode.
E.g.: Wireless handset and walkie-talkie.

14)   What is full duplex mode? Give example.
Ans: The transmission mode in which data can be transmitted in both the directions simultaneously is called full duplex mode.
E.g.: Telephone, internet etc.

15)   What is bandwidth?
Ans: Bandwidth can be defined as the maximum volume of data that can be transmitted through a communication system.

16)   How can we measure bandwidth?
Ans: We can measure bandwidth in digital devices by bits per second and in analogue devices by cycles per second or Hertz (Hz).

17)   What is communication or transmission medium?
Ans: Transmission medium is a pathway through which data are transmitted in a network.

18)   Write down the types of communication medium.
Ans: The types of communication medium are:
i) Guided or bounded or wired medium
ii) Unguided or unbounded or wireless medium

19)   What is guided medium?
Ans: Guided transmission medium are the cables that are tangible or have physical existence and are limited by the physical geography. E.g.: twisted pair cable, co-axial cable, fibre optics cable, etc.

20)   What is unguided medium?
Ans: Unguided transmission medium is the transmission medium in which data signals flow through the air or space without using any cables. E.g.: radio wave , microwave, infrared etc.

21)   What is twisted pair cable?

Ans: A pair of wires twisted with each other is known as twisted pair cable. A set of four pairs of twisted wires are bundled to form cable. These are the most common medium for LAN. Wires are twisted with each other so as to reduce the interference.

Its types are:

a)      Unshielded Twisted Pair Cable

b)      Twisted Pair Cable

22)   Differentiate between shielded and unshielded twisted pair.

Ans: The differences between shielded twisted pair and unshielded twisted pair are:

Shielded twisted pair	Unshielded twisted pair
·  It is made up of twisted pair wires with additional shielded and drain wires.	·    It is made up of twisted pair wires without additional shielded and drain wires.
·  D-shell connectors are used with shielded twisted pair.	·    RJ-45 connector is commonly used with unshielded twisted pair.

23)   What is co-axial cable?

Ans: A wire with single ended single reference where the central conductor carries the data signal.

24)   What is fiber optics cable?

Ans: Fiber optics cable is one of the costlier cables used in data communication which uses light to carry a data signal through the cable.    

25)   What are the uses of fiber optic cable?

Ans: The uses of fiber optic cables are:

a)      It is used by many telecommunication companies to transmit telephone signal.

26)   What is radio wave transmission?

Ans: The transmission making use of radio frequencies is termed  as radio wave transmission.

27)   List the advantages of radio wave transmission.

Ans: The advantages of radio wave transmission are

           a)      It offers mobility.

           b)      It offers ease of communication over different terrain.

           c)      It offers freedom from land acquisition rights that are required for laying repairing cables.

           d)      It provides cheaper than digging trenches for laying cables and maintaining repeaters and cables if cables get broken by a variety of causes.

28)   What is microwave transmission?

Ans: The transmission which involves sending signals from one microwave station to another  is called microwave transmission.

29)   What are the advantages and disadvantages of microwave transmission?

Ans: The advantages of microwave transmission are

a.       They have the ability to communicate over oceans.

b.       It offers ease of communication over difficult terrain.

The disadvantages of microwave transmission are

a.       It is an insecure communication.

b.       It is susceptible to weather effects like rain, thunder storms etc.

30)     Differentiate between radio wave and microwave communication media.

       Ans: The differences between radio wave and microwave are as follows:

Radio wave	Microwave
·  It is a form of wireless communications in which signals are sent through radio frequency waves.	·    It is a form of wireless communication in which data signals are sent through pulses of electromagnetic energy.
·  It provides low bandwidth for data communication.	·    It provides higher bandwidth for data communication.

31)   What is infrared transmission?

Ans: Infrared transmissions are just below visible transmission light which allows high speed data transmission.

32)   What is computer network?
Ans: A group of interconnected computers through transmission media in order to communicate and share resources like hardware, data and software.

33)   Write down any four advantages of computer network.
Ans: Any four advantages of computer network are as follows:
i) The computers on a network can share hardware devices like printer, hard disk, scanner etc.
ii) File can be transferred from one computer to another in a network.
iii) Computers on the network can communicate with each other.
iv) Software packages can be shared between network connected computers.

34)   Write any 4 disadvantages of computer network.

Ans: Any 4 disadvantages of computer network are as follows:
i) The sharing of information may leak the privacy of other clients.
ii) If any computer system in a network gets affected by computer virus, there is a big chance of spreading computer viruses on other computers on the network.
iii) Computers on the network have to depend on the server computer for the recourses.
iv) Data and information may be stolen by computer hackers if the security of network is not reliable.

35)   Computer Network reduces expenses of an office. Justify this statement with an example.

Ans: Computer Network reduces expenses of an office because computer on a network share different hardware devices like printers, scanners, hard disk etc. And sharing those hardware devicAes will reduces the expense of an office. For example if there are twenty computers in an office, now for printing the data there is no need to buy twenty printers individually rather than simple network the computer and connect the printer on the network which helps in sharing of the one printer among twenty computers which reduces the cost of buying nineteen printers individually.

36)   Computer Network reduces operation cost. Justify.

Ans: Computer network reduces operation cost because it takes short time to deliver information and communication is also very cheap.

37)   List the different services of computer network. [

38)   Mention the reasons of keeping computers on the network.

Ans: The reasons of keeping computers on the network are

a)      To share hardware devices like printers, scanners, hard disks etc.

b)      To share data, information and programs.

c)      To communicate with each other.

39)   Computer network makes the world a small place. Justify.

Ans: Computer network makes the world small place. It is true because in computer network we can know about the events and things place outside or inside the country sitting within a room. And we also can communicate with our relatives who are far away from us or has gone to abroad for job or study. Therefore, computer network makes the world a small place.

40)   What are the hardware and software components of a computer network?

Ans: The hardware components of a network are:

              a)      Computer system (Server or Workstation)

              b)      Network connectors

              c)      Network cables

              d)      NIC

              e)      MODEM

The software components of computer network are:

             a)      Network protocol

             b)      Network operating system

41)   What is network operating system?
Ans: Network operating system is a set of computer program that manages the resources on network.

42)   Give any four examples of network operating system.

Ans: Any four examples of network operating system are:

·         Novell network

·         Microsoft Windows NT

·         Linux

·         Unix

43)   List the main goals of computer network.

Ans: The main goals of computer network are

a.       Resource sharing

b.       Reliability

c.       Communication medium

d.       Access to remote database

e.       Easy data transfer

44)   Define hardware components.

Ans: Physical parts and devices used to connect computers in the network environment are called hardware components.

45)   What is server?

Ans: A computer on a network that allows a user to use it as a workstation and provides facilities of sharing its resources to other computers on the network is dedicated server. A computer that controls and provides hardware and software resources to other computers on the network is called non-dedicated server.

46)   Define dedicated and non-dedicated server.

Ans: A server is the main computer that provides services, data and other resources to the other computers in the network environment. Network operating software used by server are Novell Netware, Linux, Unix etc.

47)   What is workstation?
Ans: Workstation is a computer network that utilizes network resources. Network operating software used by workstation are Windows 98, Windows XP etc.

48)   What is node?
Ans: Each computer or device of network is called node.

49)   Define LAN.

Ans: A LAN is a network of computers that are relatively near to each other and are connected in a way that enables them to communicate by using cables and small wireless devices.

50)   Define MAN.

Ans: A MAN is a network of computer is computers which are spread over a metropolitan area such as within a city.

51)   Define WAN.

Ans: A WAN is a network system of connecting two or more computers generally across a wide geographical area such as cities, districts, and countries.

52)   Write down the differences between LAN and MAN.
Ans:

LAN	MAN
It is a network which covers small area i.e. within a room, building, or short distance.	It is a network which covers an entire city or a big area.
It is controlled by a single organization.	It is controlled by single or group of organization.
It uses private connection media.	It uses private or public connection media.
E.g.: network in a school, college or cyber café.	E.g.: interconnection between different branches on same branch

53)   Write down the differences between MAN and WAN.
Ans:

MAN	WAN
It is a network which covers an entire city.	It is a network that covers large area or whole world.
E.g.: interconnection between different branches on same branch	Eg. Internet

54)   Write down any three features of LAN.
Ans: Any three features of LAN are:
i) The diameter is not more than a few kilometres.
ii) LAN offers bandwidth of 10-100 Mbps.
iii) It is controlled by single organization.

55)   Write down the features of MAN.
Ans: The features of MAN are:
i) It covers a larger geographical area than LAN and connects larger number of computer.
ii) It is owned by single or multiple organizations.
iii) It uses cable or wireless communication media to connect computers.
iv) It offers a number of network services compatible with bandwidth from 128 kbps to 1 Gbps.

56)   Write down the features of WAN.
Ans: The features of WAN are:
i) It is not restricted to a geographical location. It covers whole world.
ii) It uses satellite links or microwave system to connect several LANs and MANs
iii) It is owned by multiple organizations.

iv) Data transmission in WAN is slower than LANs and WANs

57)   A WAN is composed of LANs and MANs. Justify.

Ans: A WAN is composed of LANs and MANs, it is true because big organization or offices may have branches within different zones of Nepal or outside Nepal. The branches may have different LANs and the computers on one branch may be connected with computers of other branches through telephone lines or unbounded media. i.e. MAN. So, a WAN is composed of LANs and MANs.

58)   WANs are different from  LANs. Explain.

Ans: WANs are different from LANs because WAN covers a larger geographical area whereas LAN covers very small area. WAN is owned by multiple organizations whereas LAN is owned by single organization. WAN uses public connections mediums such as telephone lines, wireless technology etc.

59)   What is network topology?
Ans: The arrangement or connection pattern of computers or nodes and other devices of the network is called network topology.

60)   List the three basic topologies.
Ans: The three basic topologies are

a)      Bus Topology

b)      Ring Topology

c)      Star Topology

61)   What is bus topology?
Ans: The network topology in which computers and other devices are arranged in linear format is called bus topology.

62)   What is ring topology?

Ans: The network topology in which computers are connected in the shape of a circle without any end points is called ring topology.

63)   What is star topology?

Ans: The network topology in which all computers or other devices are connected through a central device through a central device called hub or switch is called star topology.

64)   What are the advantages and disadvantages of ring topology?
Ans: The advantages of ring topology are :
i) It is easy it set up and configure.
ii) Each computer gets equal opportunity to access the network resources.
iii) It supports high data transmission rate.

iv) Performs better than a star topology under heavy network load.
The disadvantages of ring topology are :
i)Failure of any cable or single computers may affect the entire network.
ii) It is difficult to detect the errors.
iii) Adding/removing the devices affect the entire network.

iv) Much slower than an Ethernet network under normal load.

65)   What are the advantages and disadvantages of star topology?
Ans: The advantages of star topology are :
i) Easy to set up and configure.
ii) Failure of single computer or cable doesn’t affect the entire network.
iii) It is easy to find the fault.
iv) It is easy to extend to network by attaching new devices to the central devices.
The disadvantages of star topology are:
i) It requires more cable in comparison of bus topology so it is more costly.
ii) Failure of central devices (hub or switch) break down the whole system.

66)   What are the advantages and disadvantages of bus topology?

Ans: The advantages of bus topology are:

a)      It is easy to set up computers and other devices in bus topology, because all the devices are connected through a single wire.

b)      It requires fewer cable media, so it is cheaper than other topologies.

c)      It is easy to add new node to the network.

d)      Failure of one workstation does not affect other computers on the network.

The disadvantages of disadvantages are:

a)      The whole network system collapses if the cable or backbone is damaged.

b)      The network slows down if additional computers are connected.

c)      The limited length of the cable in a network may restrict to connect the workstation or devices.

d)      It is difficult to find fault in this network topology.

67)   What is network architecture?

Ans: The arrangement of the computers on the network which is based on the computing model is called network architecture.

Its types are

a)      Client / Server Network

b)      Peer to Peer Network

68)   What do you mean by centralized computing network.

Ans: A centralized computing network is a network in which a central host computer performs data processing and storage on behalf of clients.

69)   What is client/server network?
Ans: Client/ server network is a type of network architecture that consist of at least one server and one or more workstations.

70)   What is peer-to-peer network?
Ans: A peer to peer network is a group of computers that function as both client and server.

71)   Differentiate between client/server network and peer-to-peer network.
Ans:

Client/Server network	Peer-to-peer network
It consists of at least one server and one or more client.	It is a group of computers which function both as server and workstation.
It provides high security of data and other resources.	It provides no reliable security and might put data under risk.

72)   Write down the disadvantages of client server.
Ans: The disadvantages are:
i) It is more expensive than peer-to-peer.
ii) A well-trained network administration is required to manage network.

73)   Write down the disadvantages of peer-to-peer.
Ans: The disadvantages are
i) The expansion of network is limited.
ii) It tends to slow down with network load.

74)   What is router?
Ans: A router is an intelligent network device which connects multiple networks that uses the same protocol and forwards data packets from one network to another.

75)   What is NIC?
Ans: A Network Interface Card (NIC) is the adapter through which the computer is connected to the network.

76)   Write down the function of NIC.

Ans: The function of NIC is to convert data into electronic signals and transfer them through cables and vice-versa.

77)   What is cable?
Ans: Cables are commonly used media of physical channel for transmitting data between computers in network.

78)   What is connector?
 Ans: Connector is an interface between the NIC of the computer and the cable that passes data between computers in network.

79)   Write down the main function of NIC?
Ans: The main function of NIC is to act as the interface to connect the computer to network and control the flow of data in computer network.

80)   What is hub?
Ans: A hub is a network device that joins multiple computers or other network devices together to form a segment of computer network.

81)   What is switch?
Ans: A switch is a network device that connects computers, network devices and LAN segments.

82)   How is hub different from switch?

Ans: A hub is different from switch because a switch inspects data packets as they are received and can determine source and destination device of that packets but hub broadcasts the electric signals.

83)   What is gateway?
Ans: Gateway is a dedicated server that connects two networks having dissimilar communication protocols.

84)   What is repeater?
Ans: Repeater is a device that amplifies the incoming signals, creates a copy of it and transmits the signal on network.

85)   What is MODEM?

Ans: MODEM is a device which is used to transfer the data of one computer to another computer using telephone lines.

86)   What is the role of MODEM in data transmission?

Ans: The role of MODEM in data transmission is that it transfers data from one computer to another through telephone line. It also converts the digital signal into analog and vice versa.

87)   Write down the importance of MODEM.

Ans: The importance of MODEM are:

·         Access internet

·         Perform modulation and demodulation process

·         Transfer data from one computer to another through telephone line

88)   What is modulation?

Ans: The process of translating digital signals of a computer to analog signals, which are then transmitted across the standard telephone lines, is known as modulation.

89)   What is demodulation?

Ans: The process of translating analog signals from a phone line and converts then into digital signals for the computer is known as demodulation.

90)   What is device driver?

Ans: Device driver is a program that controls the functionality of the hardware device.