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Class: XII C++COMPUTER NETWORKS

1. Network. A network is an interconnected collection of autonomous computers.2. Nodes. The terminals attached to the network and share the resources of the network are called

nodes.3. Server. The node, which provides service to the network and at a fixed address is called server.4. LAN. A digital communication system cable of interconnecting a large number of computers,

terminals and other peripheral devices confined to relatively small areas such as a building or a group of buildings.

5. WAN. Wide area network spans a large area-possibly several continents.6. MAN. The scope of metropolitan area network lies between LANs and WANs, i.e., spanning a

small city or a town.7. Communication channels. The connecting cables are the communication channels between the

different channel workstations. The three main types of cables are twisted pair cable, coaxial cable and optical fiber cable.

8. Modem. The device that convert data from digital to analog form and vice versa.9. Topology. The pattern of interconnection of nodes in a network is called the topology.10. Internet. The internet is a global network of computers that are linked together by cables and

telephone lines making communication possible among them.11. Repeater. Repeater is used to regenerate data and voice signals.12. Bridges. A bridge is used to connect Two LANs which are physically separate but logically

same.13. Router. Router is used to load balance various paths that exist on networks. Routers can attach

physically different networks.14. Gateway. The special machine, which allows different electronic networks to talk to Internet that

uses TCP/IP, is called gateway.15. E-Mail. E-mail is a popular way of communication on the Internet. By which you can send main

to any part of the world within few seconds and without spending huge amount of money.16. Usenet. These are the special groups set up by the people who want to share common interests.17. Gopher. Gopher present the Internet as a series of hierarchical menus containing items that point

to another menu or file of a directory within a remote host as a telnet services or the articles of a Usenet newsgroup or to a variety of other things.

18. WWW. The World Wide Web is described as a “wide-area hypermedia information initiative aiming to give universal access to large universe of documents”.

19. Archie. Archie tries to locate files in public ftp archives.20. Veronica. Veronica is the one of the menu item of gopher. It is an acronym for Very Easy

Rodent Oriented Net-wide Index to Computer Archives.21. WAIS. Wide Area Information System.22. Protocol. There are some rules that govern to work on the network and these rule are also called

protocol.

PREVIOUS YEARS’ QUESTIONS {1 Mark}

1. What are repeaters? [Delhi1998, 99]2. What is the difference between LAN and MAN? [Delhi 1998]3. What do you understand by backbone network? [Delhi 1998]4. What are Routers? [AI 1998]5. What is the purpose of using a MODEM? [AI 1998]6. What is the difference between LAN and Internet? [AI 1998]7. What is the purpose of using Router? [AI 1999]8. What is the difference between LAN and WAN? [AI 1999]9. What is a bridge? [Delhi 1999]10. What is the purpose of using FTP? [Delhi 1999]11. What is the difference between WAN and MAN? [Delhi 1999]

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Class: XII C++

IMPORTANT QUESTIONS {1 Mark}

12. What are the services provided by the internet? [CBSE Quan Book]13. What is meant by full connectivity?14. What is the function of the MODEM?15. What is the Geographical scope of MAN? [CBSE Quan Book]16. What is meant by network topology? [CBSE Quan Book]17. What is Gateway? [CBSE Quan Book]18. What is meant by Internet?19. What is Archie? [CBSE Quan Book]20. Define telnet.21. Give the full form of FTP.22. Draw a diagram showing five computer nodes connected to a server in ring topology.23. Which of the following provides the maximum bandwidth:

(i) Optical fiber, (ii) Thin Ethernet, (iii) Arcnet.24. What is Mosaic used for?25. What is the full form of WWW?26. A company wants to form a network on their six computers to a server within the company premises.

Represent STAR and RING topologies diagrammatically for the above network.27. State two reasons for which you many like to have a network of computers instead of having stand

alone computers.28. Name two browsers of the Internet.29. Define server.30. What is the function of TELNET?31. A school would like to go in for network of all the computers. Which topology would you

recommend and why?32. Name the device which performs modulation and demodulation.33. Which of the following is not a transmission medium:

(i) Telephone lines, (ii) Coaxial cable, (iii) Modem, (iv) Microwave systems?34. Name one advantage of using fiber optics data transmission.35. Most data communication involving telegraph lines are .36. What is multiplexer?37. Name the communication line which is most suited for interactive processing application.38. Give one example of analog communication method.39. When was modem invented and in which country?40. Who invented the modem?41. What is the name of the network topology in which there are bi-directional links between each

possible node?42. What is the commonly used unit for measuring the speed of data transmission?43. What are the most commonly used transmission speeds in BPS used in data communication?44. Name the device which is responsible for the transfer of data from a CPU to peripheral device of a

computer.45. Which transmission mode is used for data communication along telephone lines?46. Name the basic components of data communication system.47. Define baud.48. Which topology use point-point subnet?49. What is an Rs. 232 interface?50. What is X.25 protocol?51. What is the full form of TCP/IP?52. Name the places which are using WAN.53. What is home page?54. What is HTML?55. What is SMTP?

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SPECTRUM STUDY CIRCLE (The Acme of Excellence)15/22 IInd Floor Ashok Nagar, New Delhi-110018. Ph.: 25499279, 55711031(O), 9810865706(M)

Class: XII C++PREVIOUS YEARS QUESTION [2 MARKS]

1. Describe the following brief:(i) MOSAIC, (ii) Usenet. [Delhi 1998]

2. Write the two advantages and two disadvantages of the following topologies in network. [AI 1998](i) Bus Topology, (ii) Star Topology. [AI 1998]

3. Give two advantages and two disadvantages of the following network topologies:(i) BUS, (ii) Tree. [AI 1999]

4. Give two advantages and two disadvantages of the following network topologies:(i) Star, (ii) Tree. [Delhi 1999]

IMPORTANT QUESTIONS [3 Marks]5. Name two network topologies and list one merit and one demerit of each. [CBSE Quan Book]6. Write the capabilities and services supported by LAN. [CBSE Quan Book]7. What are the facilities provided by the SERVER in a network environment? [CBSE Quan Book]8. Give at least two advantages of the E-Mail. [CBSE Quan Book]9. Write the difference between LAN, MAN and WAN.10. What is meant by Client/Server environment? [CBSE Quan Book]11. Define nodes and dumb terminals.12. What is the difference between e-mail and the fax?13. Differentiate between Circuit switching and Message switching.14. What is packet switching?15. Differentiate between DEDICATED and NON-DEDICATED SERVERS.16. What is client/server environment?17. What is the difference between Bridge and Router?18. How does communication takes place in Ring Topology?19. Name different layer of the ISO QSI layer.20. What is the different switching techniques employed to provide communication between computers?21. Give one advantage and one disadvantage of Ring Topology.22. Give merit and demerit of star topology.

CBSE QUESTIONS1. (a) What is a router?

(b) What is the use of MODEM?(c) Give the full from of WWW.(d) A company wants to form a network on their six computers to a server within the company

premises. Represent STAR and RING topologies diagrammatically for the above network?

2. (a) Give two reasons why you think networks are required.(b) Give one merit and one demerit each of the following topologies: (i) Star (ii) Ring.(c) Why do you understand by Client Server Architecture?(d) What is ARCHIE?

3. (a) Differentiate between Star and bus topology of network.(b) Write names of two communication medium used to physically connected the terminals on the

network.(c) What are ISO-OSI layers of network?(d) What do you understand by e-mail and FTP?

4. (a) What is WAIS?(b) Sharing resources is one of the sue of the networking comment.(c) Differentiate between circuit switching and message switching.(d) What is protocol?

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Class: XII C++

5. (a) What is a bridge?(b) What is the purpose of using FTP?(c) Give two advantages and two disadvantages of following network topologies: (i) Star (ii) Tree(d) What is the difference between WAN and MAN?

SOME IMPORTANT BOARD QUESTIONS

Q1. (a) What are Routers?(b) What is the purpose of using Modem?(c) Write the two advantages and two disadvantages of Bus Topology in network.(d) What is the difference between LAN and WAN?

Ans. (a) On Internet it is not necessary that all the packets will follow the same path from source to destination. A special machine router tries to load balance between various paths that exists on networks.

(b) MODEM is used to convert digital data into analog form and vice versa.(c) Advantages of BUS Topology:

(i) Short cable length – Because there is single common data path connecting all nodes.(ii) Easy to extend – Additional nodes can be connected to an existing bus network at any

point along its length.Disadvantages of BUS Topology:(i) Fault diagnosis is difficult – Although the bus topology is very simple, but in this topology

fault detection is very difficult.(ii) Nodes must be intelligent – Each node on the network is directly connected to the central

bus. This means that some way of deciding who can use the network at any given time must be performed in each node. It tends it increase the cost of the nodes irrespective of whether this is performed in hardware or software.

(d) (i) A LAN is confined to restricted distance up to one building or near by building. On the other hand scope of WAN is up to one continent. (ii) Because of the short distances involved, the error rates in LANs are much lower than WANs.

Q2. (a) What are Repeaters?(b) Name the device used to connect a computer to an analog telephone line.(c) Briefly mention two advantages and two disadvantages of Star topology in network.(d) What is the difference between MAN and WAN?

Ans. (a) Sometimes the signals on the Internet are become weaker before reaching the destination node. Repeater is used to regenerate data and voice signals. Repeater read the incoming signals and amplified it and transmitted to another segment of the network. (b) MODEM

(c) Advantages of Star Topology:(i) Ease of service – The star topology has a number of concentration point i.e., at the central

node or at intermediate wiring closets. These provide easy occurs for service or re-configuration of the network.

(ii) One device per connection: In star topology, failure of a single connection typically involves disconnecting one node from an other.

Disadvantages of Star Topology:(i) Long cable length : Because each node in star topology is directly connected to the center,

the star topology requires a large quantity of cable.(ii) Central node dependency : If the central node fails the network get failed.

(d) (i) A MAN is confined to ONE CITY OR TOWN. On the other hand scope of WAN is up to one continent. (ii) Because of the short distances involved, the error rates in MANs are much lower than WANs.

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Class: XII C++

Q3. (a) What are Bridges?(b) Mention the advantages of e-mail over conventional mailing system.(c) Briefly mention two advantages and disadvantages of Ring topology in network.

(d) What is the difference between MAN and LAN?

Ans. (a) A bridge is used to connect two LANs, which are physically separated but logically same.(b) E-Mail is the electronic mail. Electronic mail is usually used to exchange messages and data files

than conventional mailing system. Each used is assigned an electronic mailbox. Using the appropriate command, the used can scan a list of the messages in the mailbox, display the contents of a particular message, send a message to another user and so forth.

(c) Advantages of Ring Topology:(i) Short cable length. In ring topology less connections will be needed which increase

network reliability.(ii) The amount of cable needed in this topology is comparable to bus and small relative to

star.Disadvantages of Ring Topology:(i) Node failure causes network failure: Since each node in this network connected to its

neighboring node and data is travel through each node. So, there is one traffic flow until defective node is removed.

(d) (i) A MAN is confined to ONE CITY OR TOWN. On the other hand scope of WAN is up to one continent.

(ii) A LAN is confined to restricted distance up to one building or near by building or near by building. On the other hand scope of WAN is up to one continent.

Q4. (a) What are backbone networks?(b) Name two switching circuits and explain any one.(c) Mention one difference between Circular and Star topologies in networking.

Ans. (a) When we connect number of LANs to form one WAN the network, which is used as a backbone to connect the LANs is called backbone network.

(b) The two switching circuits are : Circuit switching and Message switching. Circuit Switching: In this technique, first the complete physical connection between two

computers is established and then data is transmitted from the source computer to the destination computer.

(c) the circular topology has: Short cable length. In circular topology less connections will be needed which increase network

reliability. The amount of cable needed in this topology is comparable to bus and small relative to star topologies.

The star topology has: One Device per connection and Long cable length.

Q5. (a) What is NFS?(b) Mention one advantage of networking.(c) Name two communication channels used in networking and explain any one.(d) Mention one difference between Linear and Star topologies in networking.

Ans. (a) NFS (Network File System) allow computers to share files across a network or networks. NFS is computer – independent and is also independent of lower layers, such as the transport layer, because it rests above the RPC (Remote Procedure Calls).

(b) The advantage of networking is to share computer equipment and programs, messages and the information available at one site.

(c) Two communication channels are: Twisted pair cable and Coaxial cable. Twisted pair cable. The most common form of wiring in data communication applications is the

wiring. It consists of two identical wires in the pair have the same impedance to ground, making

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Class: XII C++

it a balanced medium. This characteristic helps to lower the cable’susceptibility to noise from neighboring cables or external sources.

(d) The linear topology has short Cable length and easy to extend. The star topology has one Device per connection and easy to access.

Q6. (a) Compare coaxial and optical fiber cable.(b) Write the following abbreviations in their full form: LAN, OSI(c) What is the purpose of Telnet?(d) Write two advantages and disadvantages of the following topologies in network:

(i) Star(ii) Tree

Ans. (a) Coaxial cable. It consists of a solid wire core surrounded by one or more foil or braided wire shields, each separated from the other by some kind of plastic insulator. It is mostly used in the cables wires.

Optical fibre cable. It consists of thin strands of glass or glass-line material which are so connected that they carry light from source at one end to destination at the other end. The main advantage of this cable is their complete immunity to noise. But this cable is very expensive as compared to the coaxial cable.(b) LAN – Local area Network OSI – Open Systems Interconnection.(c) Telnet is an Internet facility that facilitates remote login.(d) (i) Advantages of STAR topology

1. One Device per connection2. Easy to access

Disadvantages of STAR topology 1. Long cable length2. Central node dependency

(ii) Advantages of TREE topology1. Easy to extend2. Fault isolation is easy

Disadvantages of TREE topology1. Dependent on the root computer2. Complex access protocols

Q7. (a) What is MODEM?(b) Write the following abbreviations in their full form:

FTP, WAN, WWW(c) Mention one difference between circuit switching and packet switching.(d) Write two advantages and disadvantages of the following topologies in network:

(i) Bus(ii) Ring

Ans. (a) A modem is a device which is used to convert digital data into analog form and vice versa.(b) FTP. File Transfer Protocol WAN. Wide Area Network WWW. World Wide Web.(c) Circuit Switching. In this technique firstly the complete physical connection between two

computers is established and then data is transmitted from the source computer to the destination computer.

A Packet Switching network divides the data traffic into blocks called packets that have a maximum length. Each packet of user data travels in a data envelope, which gives the destination address of the packet and a variety of control information.

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Class: XII C++

(d) Advantages of BUS topology: (i) Short cable length – Because there is single common data path connecting all nodes.(ii) Easy to extend – Additional nodes can be connected to an existing bus network at any

point along its length.

Disadvantages of BUS topology:(i) Fault diagnosis is difficult – Although the bus topology is very simple, but in this topology

fault detection is very difficult.(ii) Nodes must be intelligent – Each node on the network is directly connected to the central

bus. This means that some way of deciding who can use the network at any given time must be performed in each node. It tends to increase the cost of the nodes irrespective of whether this is performed in hardware or software.

Advantages of Ring topology:(i) Short cable length – In ring topology less connections will be needed which increases

network reliability.(ii) The amount of cable needed in this topology is comparable to bus and relatively small to

star.

Disadvantages of Ring topology:(i) Node failure causes network failure – Since each node in this network is connected to its

neighbouring node and data travels through each node, there is one traffic flow until defective node is removed.

(ii) Each node must handle the data being transferred on the ring.

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Class: XII C++COMPUTERS NETWORK

TERMINOLOGIES USED IN NETWORKING

1. N.I.U : NETWORK INTERFACE UNIT2. TAP : TERMINAL ACCESS POINT3. ARPANET : ADVANCED RESEARCH PROJECT NETWORK4. NSF NET : NATIONAL SCIENCE FOUNDATION NETWORK5. INTERNET : INTER CONNECTION OF NETWORKS (INTERNETWORKING)6. TCP/IP : TRANSMISSION CONTROL PROTOCOL / INTERNET

PROTOCOL7. VGM : VOICE GRADE MEDIUM8. DGM : DATA GRADE MEDIUM9. bPS : BITS PER SECOND10. BPS : BYTES PER SECOND (1 BYTE = 8 BITS)11. KbPS : KILO BITS PER SECOND12. KBPS : KILO BYTES PER SECOND13. mbps : MEGA BITS PER SECOND14. Mbps : MEGA BYTES PER SECOND (106)15. TBPS : TERA BYTES PER SECOND (1012)16. LAN : LOCAL AREA NETWORK17. WAN : WIDE AREA NETWORK18. MAN : METROPOLITAN AREA NETWORK19. P2P : POINT-TO-POINT20. W.S. : WORK STATION21. FTP : FILE TRANSFER PROTOCOL22. SLIP : SERIAL LINE INTERNET PROTOCOL23. PPP : POINT TO POINT PROTOCOL24. IPCP : INTERNET PROTOCOL CONTROL PROTOCOL25. NCPS ; NETWORK CONTROL PROTOCOL26. LCP : LINK CONTROL PROTOCOL27. GSM : GLOBAL SYSTEM FOR MOBILE COMMUNICATION28. SIM : SUBSCRIBER IDENTIFICATION MODULE29. TDMA : TIME DIVISION MULTIPLE ACCESS30. IDEN : INTEGRATED DIGITAL ENHANCED NETWORK31. CDMA : CODE-DIVISION MULTIPLE ACCESS32. WLL : WIRELESS IN LOCAL LOOP OR WILL33. PSTN : PUBLIC SWITCHED TELEPHONE NETWORK34. 3G : THIRD GENERATION35. EDGE : ENHANCED DATA RATES FOR GLOBAL EVOLUTION36. SMS : SHORT MESSAGE SERVICE37. SMSC : SHORT MESSAGE SERVICE CENTRE38. E MAIL : ELECTRONIC MAIL39. WWW : WORLD WIDE WEB40. HTTP : HYPER TEXT TRANSFER PROTOCOL41. URL : UNIFORM RESOURCE LOCATOR42. HTML : HYPER TEXT MARKUP LANGUAGE 43. DNS : DOMAIN-NAME SYSTEM44. POP : POST OFFICE PROTOCOL45. SMTP : SIMPLE MAIL TRANSFER PROTOCOL46. XML : EXTENSIBLE MARK-UP LANGUAGE47. DHTML : DYNAMIC HTML

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Class: XII C++

48. MODEM : MODULATOR – DEMODULATOR49. AM : AMPLITUDE MODULATION50. FM : FREQUENCY MODULATION51. PM : PHASE MODULATION52. RJ-45 : REGISTER JACK – 4553. DCE : DATA COMMUNICATION EQUIPMENT54. BNC : BAYONE NEILL CONCETMAN55. WAIS : WIDE AREA INFORMATION SYSTEM56. RPC : REMOTE PROCEDURE CALLS57. OSI : OPEN SYSTEMS INTERCONNECTION58. ISP : INTERNET SERVICE PROVIDER59. NIC : NETWORK INTERFACE CARD60. NFS : NETWORK FILE SYSTEM61. UTP : UNSHIELDED TWISTED PAIR CABLE.62. STP : SHIELDED TWISTED PAIR CABLE63. DTE : DATA TERMINAL EQUIPMENT64. VFIR : VERY FAST INFRARED65. PDA : PERSONAL DATA ASSISTANT 66. WCDMA : WIDE BAND CDMA67. HLR : HOME LOCATION REGISTER68. IE : INTERNET EXPLORER69. NTP : NETWORK TIME PROTOCOL70. IMAP : INTERNET MAIL ACCESS PROTOCOL71. LEDS : LIGHT EMITTING PAIR72. LDS : LASER DIODES73. KHZ : KILOHERTZ74. MHZ : MEGAHERTZ75. GHZ : GIGAHERTZ76. THZ : TERAHERTZ77. A/F : AUDIO FREQUENCY78. DTR : DATA TERMINAL READY79. DSR : DATA SET READY80. RTS : REQUEST TO SEND81. CD : CARRIER DETECT82. CTS : CLEAR TO SEND83. SNA : SYSTEMS NETWORK ARCHITECTURE84. URI : UNIFORM RESOURCE IDENTIFIER85. URN : UNIFORM RESOURCE NAME86. LCP : LINK CONTROL PROTOCOL87. USC : UNIQUE SPREADING CODE.88. WLL/WILL : WIRELESS IS LOCAL LOOP89. UMTS : UNIVERSAL MOBILE TELECOMMUNICATION SYSTEMS90. WCDMA : WIDE BAND CDMA.

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