Computer Science Workshop: Grade XII



(CBSE Board Exam QP from 1998 to 2010)

Networks

Year 2010 (Outside Delhi)

7. (a) What was the role of ARPANET in the Computer Network?

Ans.: In 1969 US Department of Defense started ARPANET ( Advanced Research Projects Agency NETwork) to connect computers at US defense and different universities. Today’s Internet has evolved from ARPANET along with some other networks such as NSF(National Science Foundation) net and other private networks.

(b) Which of the following is not a unit for data transfer rate?

(i) mbps

(ii) kbps

(iii) sbps

(iv) gbps

Ans.: (iii) sbps is not a unit of data transfer rate.

(c) What is the difference between Virus and Worms in the computers?

Ans.:

|Virus |Worm |

|A computer virus is a program that gets into a computer |Computer Worms are like a virus in the fact that they do |

|system by means of hardware or software without the knowledge|self-replicate themselves within your computer system. |

|of the computer user, and then attaches itself to a program |However, a computer worm does not have to attach itself to|

|file. |a program in your system like a computer virus does in |

| |order to function. |

|A computer virus attaches itself to a program or file |A worm is similar to a virus by design and is considered |

|enabling it to spread from one computer to another, leaving |to be a sub-class of a virus. Worms spread from computer |

|infections as it travels. Like a human virus, a computer |to computer, but unlike a virus, it has the capability to |

|virus can range in severity: some may cause only mildly |travel without any human action. A worm takes advantage of|

|annoying effects while others can damage your hardware, |file or information transport features on your system, |

|software or files. |which is what allows it to travel unaided. |

|Almost all viruses are attached to an executable file, which |The biggest danger with a worm is its capability to |

|means the virus may exist on your computer but it actually |replicate itself on your system, so rather than your |

|cannot infect your computer unless you run or open the |computer sending out a single worm, it could send out |

|malicious program. It is important to note that a virus |hundreds or thousands of copies of itself, creating a huge|

|cannot be spread without a human action, (such as running an |devastating effect. One example would be for a worm to |

|infected program) to keep it going.  |send a copy of itself to everyone listed in your e-mail |

| |address book. Then, the worm replicates and sends itself |

| |out to everyone listed in each of the receiver's address |

| |book, and the manifest continues on down the line.  |

|People continue the spread of a computer virus, mostly |Due to the copying nature of a worm and its capability to |

|unknowingly, by sharing infecting files or sending e-mails |travel across networks the end result in most cases is |

|with viruses as attachments in the e-mail. |that the worm consumes too much system memory (or network |

| |bandwidth), causing Web servers, network servers and |

| |individual computers to stop responding. In recent worm |

| |attacks such as the much-talked-about Blaster Worm, the |

| |worm has been designed to tunnel into your system and |

| |allow malicious users to control your computer remotely. |

(d) What term do we use for a software/hardware device, which is used to block unauthorized access while permitting authorized communications? This term is also used for a device or set of devices configured to permit, deny, encrypt, decrypt, or proxy all (in and out) computer traffic between different security domains based upon a set of rules and other criteria.

Ans.: Firewall

(e) “Vidya for All” is an educational NGO. It is setting up its new campus at Jaipur for its web-based activities. The campus has four buildings as shown in the diagram below: 4

Center to center distances between various buildings as per architectural drawings (in meters) is as follows:

|Main Building to Resource Building |120 m |

|Main Building to Training Building |40 m |

|Main Building to Accounts Building |135 m |

|Resource Building to Training Building |125 m |

|Resource Building to Accounts Building |45 m |

|Training Building to Accounts Building |110 m |

Expected Number of Computers in each Building is as follows:

|Main Building |15 |

|Resource Building |25 |

|Training Building |250 |

|Accounts Building |10 |

(e1) Suggest a cable layout of connections between the buildings.

Layout 1

Layout 2

(e2) Suggest the most suitable place (i.e. building) to house the server for this NGO.

Also, provide a suitable reason for your suggestion.

Ans,: The most suitable place / block to house the server of this NGO would be Training Building, as this block contains the maximum number of computers, thus decreasing the cabling cost for most of the computers as well as increasing the efficiency of the maximum computers in the network.

(e3) Suggest the placement of the following devices with justification:

i) Repeater

ii) Hub/ Switch

Ans.: (i) Repeater: For Layout 1, since the cabling distance between Training Building and Account Building is quite large, so a repeater would ideally be needed along their path to avoid loss of signals during the course of data flow in these routes. For layout 2, since the distance between Training Building and Resource Building and distance between Training Building and Account Building is large so a repeater would ideally be placed in between these paths

Layout 1

Layout 2

(ii) Hub/Switch: In both the layouts, a hub/switch each would be needed in all the Buildings , to interconnect the group of cables from the different computers in each Building

Layout 1

Layout 2

(e4) The NGO is planning to connect its International office situated in Delhi. Which

out of the following wired communication links, will you suggest for a very high

speed connectivity?

i) Telephone Analog Line

ii) Optical Fiber

iii) Ethernet Cable

Ans. (ii) Optical Fiber: will provide a very high speed connectivity.

(f) Write the full forms of the following: 1

(i) FTP

(ii) FSF

Ans. : (i) FTP: File Transfer Protocol

(ii) FSF: Free Software Foundation

(g) Name any two common Web browsers. 1

Ans: Two most popular Web browsers are:

i) Internet Explorer

ii) Netscape Navigator

Year 2009 (Delhi)

7. (a) What is difference between Star Topology and Bus Topology of network? 1

Ans Bus Topology: It is characterized by common transmission medium shared by

all the connected hosts, managed by dedicated nodes. It offers simultaneous

flow of data and control.

[pic]

Star Topology: It is characterized by central switching node (communication

controller) and unique path (point to point link) for each host. It is easy to add

and remove additional hosts by upgrading the centralized node

[pic]

(1 Mark for correct difference, either Textual or Diagrammatical)

OR

( ½ Mark for correct Textual/Diagrammatical explanation of either Bus or

Star Topology

(b) Expand the following abbreviations: 1

(i) GSM

(ii) CDMA

Ans (i) Global System for Mobile Communication

(ii) Code Division Multiple Access

( ½ Mark tor correct expansion of GSM)

( ½ Mark for correct expansion of CDMA)

(c) What is protocol? Which protocol is used to search information from internet

using an internet browser? 1

Ans A protocol is the set of rules for governing communication between two

communication devices. It also infers documentation, negotiations and

establishment of rules.

Protocol used to search information from internet using an internet browser is :

TCP/IP OR HTTP

(½ Mark for explaining protocol correctly)

(½ Mark for TCP/IP or HTTP)

(d) Name two switching techniques used to transfer data between two terminals

(computers ). 1

Ans Message Switching and Packet Switching

OR

Circuit Switching and Message Switching

OR

Circuit Switching and Packet Switching

(½ Mark for first switching technique)

(½ Mark for second switching technique)

(e) Freshminds University of India is starting its first campus in Ana Nagar of

South India with its center admission office in Kolkata. The university has 3

major blocks comprising of Office Block, Science Block and Commerce

Block in the 5 KM area Campus.

As a network expert, you need to suggest the network plan as per (El) to

(E4) to the authorities keeping in mind the distance and other given parameters.

[pic]

Expected Wire distances between various locations:

[pic]

Expected number of Computers to be installed’ at various locations in the

University are as follows:

[pic]

(E1) Suggest the authorities, the cable layout amongst various blocks inside

university campus for connecting the blocks. 1

Ans

[pic]

(1 Mark for mentioning any valid connectivity or topology or diagram

connecting various blocks inside university campus)

(E2) Suggest the most suitable place (i.e. block) to house the server of this

university with a suitable reason. 1

Ans Science Block as it contains maximum number of computere.

(½ Mark for mentioning the block)

(½ Mark for correct reason)

Note: 1 mark if Commerce Block is written with valid justification eg.

Minimum wiring needed

(E3) Suggest an efficient device from the following to be installed in each of the

blocks to connect all the computers: 1

(i) MODEM

(ii) SWITCH

(iii) GATEWAY

Ans SWITCH

( 1 Mark for correct device)

(E4) Suggest the most suitable. (very high speed) service to provide data connectivity

between Admission Office located in Kolkata and the campus

located in Ana Nagar from the following options: 1

• Telephone line

• Fixed-Line Dial-up connection

• Co-axial Cable Network

• GSM

• Leased line

• Satellite Connection

Ans Satellite Connection

OR

Leased line

(1 Mark for correct service name)

Year 2009 (Outside Delhi)

7. (a) What is the difference between LAN and WAN? 1

Ans LAN (Local Area Network):

Interconnects a high number of access or node points or stations within a

confined physical area. An example is the territory covered in a single office

building that houses various departments/offices. All these areas are

interconnected using a LAN.

[pic]

WAN (Wide Area Network)

It is used to connect systems with no limitation of geographical area. It is used

to serve many locations distributed over a large geographical area.

A system of overnight teller machines used by a banking organisation covering

the North of India is an example of a WAN. Internet is also an example of the

same.

[pic]

(1 Mark for correct difference, either Textual or Diagrammatical)

OR

( ½ Mark each for correct Textual/Diagrammatical explanation of LAN or WAN)

(b) Expand the following abbreviations: 1

(i) HTTP

(ii) ARPANET

Ans (i) Hyper Text Transfer Protocol

(ii) Advanced Research Projects Agency Network

(½ Mark for correct expansion of HTTP)

(½ Mark for correct expansion of ARPANET)

(c) What is protocol? Which protocol is used to copy a file from/to a remotely

located server? 1

Ans A protocol is the set of rules for governing communication between two

communication devices. It also infers documentation, negotiations and

establishment of rules.

Protocol used to copy a file from / to a remotely located server is FTP (File

Transfer Protocol)

(½ Mark for explaining protocol correctly)

(½ Mark for FTP)

(d) Name two switching techniques used to transfer data between two terminals

(computers). 1

Ans Message Switching and Packet Switching

OR

Circuit Switching and Message Switching

OR

Circuit Switching and Packet Switching

(½ Mark for naming first switching technique)

(½ Mark for naming second switching technique)

(e) Eduminds University of India is starting its first campus in a small town Parampur

of Central India with its center admission office in Delhi. The university has 3

major buildings comprising of Admin Building, Academic Building and Research

Building in the 5 KM area Campus.

As a network expert, you need to suggest the network plan as per (E1) to

(E4) to the authorities keeping in mind the distances and other given

parameters.

[pic]

Expected Wire distances between various locations:

[pic]

Expected number of computers to be installed at various locations in the

university are as follows:

[pic]

(E1) Suggest to the authorities, the cable layout amongst various buildings

inside the university campus for connecting the buildings. 1

Ans

[pic]

(1 Mark for mentioning any valid connectivity or topology or diagram

connecting various buildings inside university campus)

(E2) Suggest the most suitable place (i.e. building) to house the server of this

organisation, with a suitable reason. 1

Ans Academic Building as it contains maximum number of computers.

( ½ Mark for mentioning the building)

( ½ Mark for correct reason)

Note: 1 mark if any suitable place/building is suggested with valid justification

(E3) Suggest an efficient device from the following to be installed in each of

the buildings to connect all the computers : 1

(i) GATEWAY

(ii) MODEM

(iii) SWITCH

Ans SWITCH

( 1 Mark for correct device)

(E4) Suggest the most suitable (very high speed) service to provide data

connectivity between Admission Building located in Delhi and the

campus located in Parampur from the following options: 1

• Telephone line

• Fixed-Line Dial-up connection

• Co-axial Cable Network

• GSM

• Leased line

• Satellite Connection

Ans. Satellite Connection

OR

Leased line

(1 Mark for correct service name)

Sample Paper by CBSE Set-1

Q7.

a) What is the significance of ARPANET in the network? 1

Answer:

The first evolution of network was jointly designed by The Advanced Research Projects Agency (ARPA) and Department of Defence (DoD) in 1969 and was called ARPANET. It was an experimental project, which connected a few computers of some of the reputed universities of USA and DoD. ARPANET allowed access and use of computer resource sharing projects. Later Defence Data Network (DDN) was born in 1983.

(1 marks for mentioning the significance correctly)

b) Expand the following terminologies: 1

(i) CDMA (ii) GSM

Answer:

i) Code Division Multiple Access

ii) Global System for Mobile Communication

(½ mark each expansion)

c) Give two major reasons to have network security. 1

Answer:

Two major reasons to have Network Security are

(i) Secrecy: Keeping information out of the reach of unauthorized users.

(ii) Authentication: Determining the authorized user before sharing sensitive information with or entering into a business deal.

(½ mark for each appropriate reasons)

d) What is the purpose of using a Web Browser? Name any one commonly used Web Browser. 1

Answer:

The Web Browser fetches the page requested, interprets the text and formatting commands that it contains, and displays the page properly formatted on the screen.

Example of a Web Browser:

Mozilla Firefox OR Internet Explorer OR Netscape Navigator OR Safari OR OPERA

(½ mark for mentioning purpose of using a Web Browser)

(½ mark for Example of a Web Browser)

e) Knowledge Supplement Organization has set up its new center at Mangalore for its office and web based activities. It has 4 blocks of buildings as shown in the diagram below:

Center to center distances between various blocks

|Block A to Block B |50 m |

|Block B to Block C |150 m |

|Block C to Block D |25 m |

|Block A to Block D |170 m |

|Block B to Block D |125 m |

|Block A to Block C |90 m |

Number of Computers

|Black A |25 |

|Block B |50 |

|Block C |125 |

|Block D |10 |

e1) Suggest a cable layout of connections between the blocks. 1

Answer:

(Any of the following option)

Layout Option 1:

Layout Option 2: Since the distance between Block A and Block B is quite short

(1 mark for any of the above shown Layout)

e2) Suggest the most suitable place (i.e. block) to house the server of this organisation with a suitable reason. 1

Answer:

The most suitable place / block to house the server of this organisation would be Block C, as this block contains the maximum number of computers, thus decreasing the cabling cost for most of the computers as well as increasing the efficiency of the maximum computers in the network.

( ½ mark for mentioning the correct block)

( ½ mark for reason)

e3) Suggest the placement of the following devices with justification 1

i) Repeater

ii) Hub/Switch

Answer:

i) For Layout 1, since the cabling distance between Blocks A and C, and that between B and C are quite large, so a repeater each, would ideally be needed along their path to avoid loss of signals during the course of data flow in these routes.

For layout 2, since the distance between Blocks A and C is large so a repeater would ideally be placed in between this path

(1 mark for showing correct placement of repeater)

ii) In both the layouts, a hub/switch each would be needed in all the blocks, to interconnect the group of cables from the different computers in each block

Layout 1

Layout 2

(1 mark for showing correct placement of hub)

e4) The organization is planning to link its front office situated in the city in a hilly region where cable connection is not feasible, suggest an economic way to connect it with reasonably high speed? 1

Answer:

The most economic way to connect it with a reasonable high speed would be to use radio wave transmission, as they are easy to install, can travel long distances, and penetrate buildings easily, so they are widely used for communication, both indoors and outdoors. Radio waves also have the advantage of being omni directional, which is they can travel in all the directions from the source, so that the transmitter and receiver do not have to be carefully aligned physically.

(1 mark for suggesting the appropriate economic way)

Sample Paper by CBSE Set-2

7.

a) Define the term Bandwidth. Give unit of Bandwidth. 1

Answer:

Bandwidth is the capability of a medium to transmit an amount of information over a distance. Bandwidth of a medium is generally measured in bits per second (bps) or more commonly in kilobits per second (kbps)

( ½ Mark for correct definition and ½ Mark for correct unit)

b) Expand the following terminologies: 1

(i) HTML (ii) XML

Answer:

i) Hypertext Markup Language

ii) Extended Markup Language

( ½ Mark for each correct expansion)

c) Define the term firewall. 1

Answer:

Firewall is a feature used for Network Security. In a Network there is always danger of information leaking out or leaking in. Firewall is a feature which forces all information entering or leaving the network to pass through a check to make sure that there is no unauthorized usage of the network.

(1 Mark for correct definition)

d) What is the importance of URL in networking? 1

Answer:

URL stands for Uniform Resource Locator. Each page that is created for Web browsing is assigned a URL that effectively serves as the page’s worldwide name or address. URL’s have three parts: the protocol , the DNS name of the machine on which the page is located and a local name uniquely indicating the specific page(generally the filename).

(1 Mark for correct significance)

e)

Ravya Industries has set up its new center at Kaka Nagar for its office and web based activities. The company compound has 4 buildings as shown in the diagram below:

Center to center distances between various buildings is as follows:

|Harsh Building to Raj Building |50 m |

|Raz Building to Fazz Building |60 m |

|Fazz Building to Jazz Building |25 m |

|Jazz Building to Harsh Building |170 m |

|Harsh Building to Fazz Building |125 m |

|Raj Building to Jazz Building |90 m |

Number of Computers in each of the buildings is follows:

|Harsh Building |15 |

|Raj Building |150 |

|Fazz Building |15 |

|Jazz Bulding |25 |

e1) Suggest a cable layout of connections between the buildings. 1

Answer:

Layout 1:

Layout 2: Since the distance between Fazz Building and Jazz Building is quite short

(1 Mark for appropriate layout)

e2) Suggest the most suitable place (i.e. building) to house the server of this organisation with a suitable reason. 1

Answer:

The most suitable place / block to house the server of this organisation would be Raj Building, as this block contains the maximum number of computers, thus decreasing the cabling cost for most of the computers as well as increasing the efficiency of the maximum computers in the network.

(1 mark for correct placement)

e3) Suggest the placement of the following devices with justification: 1

i) Internet Connecting Device/Modem

ii) Switch

Answer:

i) Raj Building

ii) In both the layouts, a hub/switch each would be needed in all the buildings, to interconnect the group of cables from the different computers in each block

( ½ Mark for placement of each device correctly)

e4) The organisation is planning to link its sale counter situated in various parts of the same city, which type of network out of LAN, MAN or WAN will be formed? Justify your answer. 1

Answer:

The type of network that shall be formed to link the sale counters situated in various parts of the same city would be a MAN, because MAN (Metropolitan Area Networks) are the networks that link computer facilities within a city.

( ½ mark for correct type and ½ mark for correct justification)

Year 2008 (Outside Delhi)

7. (a) What is a Modem?

Ans: Modem is a Modulation Demodulation device that converts analog signal to

digital signal and vice versa.

(1 Mark for any correct definition/explanation)

(b) Expand the following terms with respect to Networking :

(i) PPP (ii) GSM (iii) XML (iv) HTTP

Ans: (i) Point To Point Protocol

(ii) Global System for Mobile Communication

(iii) eXtensible MarkUp Language

(iv) Hyper Text Transfer Protocol

(½ Mark for each correct expansion)

(c) How is a Hacker different from a Cracker?

Ans:

Hackers are the ones who get into someone’s code or computer without any

malicious intentions, where as Crackers are the one’s who get into someone’s

code or computer with malicious intentions.

OR

Any equivalent difference

(½ Mark for each correct definition)

(d) “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 set up their main office units 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 as follows:

Approximate distances between these Units is as follows:

|From |To |Distance |

|Production Unit |Finance Unit |70 Mtr |

|Production Unit |Media Unit |15 Km |

|Production Unit |Corporate Unit |2112 Km |

|Finance Unit |Media Unit |15 Km |

In continuation of the above, the company experts have planned to install the

following number of computers in each of their office units:

|Production Unit |150 |

|Finance Unit |35 |

|Media Unit |10 |

|Corporate Unit |30 |

(i) Suggest the kind of network required (out of LAN, MAN, WAN) for

connecting each of the following office units:

• Production Unit and Media Unit

• Production Unit and Finance Unit

Ans:

• Production Unit and Media Unit : MAN

• Production Unit and Finance Unit : LAN

(½ Mark for mention of each - MAN and LAN correctly)

(ii) Which one of the following device will you suggest for connecting all

the computers within each of their office units?

• Switch/Hub

• Modem

• Telephone

Ans:

• Switch/Hub

(1 Mark for the correct device)

(iii) Which of the following communication media, will you suggest to be

procured by the company for connecting their local offices in Chennai

for very effective (High Speed) communication?

• Ethernet cable

• Optical Fiber

• Telephone cable

Ans:

• Optical Fiber

(1 Mark for the correct media)

(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.

Ans:

Optical Fiber/Star Topology

Wireless/Satellite Link/leased Line

(½ Mark for the correct layout)

(½ Mark for the equivalent correct method/technology)

Year 2008 (Delhi)

7. (a) What is a Hub? 1

Ans: A Hub is used for a central connection between two or more computers on a

network.

OR

A Hub is a network device used to connect two or more computers.

OR

A Hub is an unintelligent network device to connect computers.

(1 Mark for any correct definition / explanation)

(b) Expand the following terms with respect to Networking: 2

(i) Modem (ii) WLL (iii) FTP (iv) TCP/IP

Ans:

(i) Modulator - Demodulator

(ii) Wireless Local Loop OR Wireless in Local Loop

(iii) File Transfer Protocol

(iv) Transfer Control Protocol/Internet Protocol

(½ Mark for each correct expansion)

(c) How is Coaxial cable different from Optical Fibre? 1

Ans: Coaxial Cable: Comparatively Slow, Economic, convenient to lay down, used

in Bus topology of networks

Optical Fibre: Very fast, expensive, reliable, no interference

(1 Mark for mentioning anyone valid difference)

OR

(½ Mark for anyone characteristic each of Coaxial Cable or Optical

Fibre)

(d) “Bias Methodologies” is planning to expand their network in India, starting

with three cities in India to build infrastructure for research and development

of their chemical products. The company has planned to setup their main

office in Pondicherry - at three different locations and have named their offices

as “Back Office”, “Research Lab” and “Development Unit”. The company

has one more Research office namely “Corporate Office” in “Mumbai”. A

rough layout of the same is as follows : 4

Approximate distances between these offices are as follows:

|From |To |Distance (Km) |

|Research Lab |Back Office |0.11 |

|Research Lab |Development Office |16 |

|Research Lab |Corporate Unit |1800 |

|Back Office |Development Office |13 |

In continuation of the above, the company experts p.aye planned to install the

following number of computers in each of their offices:

|Research Lab |158 |

|Back Office |79 |

|Development Office |90 |

|Corporate Unit |51 |

(i) Suggest the kind of network required (out of LAN, MAN, WAN) for

connecting each of the following office units:

• Research Lab and Back Office

• Research Lab and Development Unit

Ans: Research Lab and Back Office - LAN

Research Lab and Development Unit - MAN

(½ Mark for each answer)

(ii) Which one of the following device will you suggest for connecting all

the computers within each of their office units?

• Switch/Hub

• Modem

• Telephone

Ans: Switch I Hub

(1 Mark for mentioning correct option)

(iii) Which of the following communication medium, you will suggest to be

procured by the company for connecting their local office units in

Pondicherry for very effective (High Speed) communication?

• Telephone Cable

• Optical Fiber

• Ethernet Cable

Ans: Optical Fibre

(1 Mark for mentioning correct option)

(iv) Suggest a cable/wiring layout for connecting the company's local office

units located in Pondicherry. Also, suggest an effective method/

technology for connecting the company's office unit located in Mumbai.

Ans: Local office units at Pondicherry to be connected using LAN / MAN / star

Topology / Tree Topology

Mumbai Office to be connected using Satellite/WAN

(½ Mark for mentioning valid connectivity or topology or diagram for

local office in Pondicherry)

(½ Mark. for mentioning valid connectivity or topology or diagram for

Mumbai office)

YEAR 2007 (DELHI)

7. (a) What is the significance of Cyber Law ? 1

(a) Cyber law encompasses a wide variety of political and legal issues related

to the Internet and other communications technology, including intellectual

property, privacy, freedom of expression, and jurisdiction.

OR

Restricting unauthorized access to user accounts. Promoting, coordinating

and controlling e-business.

(1 Mark for any correct definition/explanation)

(b) Expand the following terms with respect to Networking : 2

(i) XML

(ii) WWW

(iii) WLL

(iv) TCP/IP

(b) (i) XML eXtensible MarkUp Language

(ii) WWW World Wide Web

(iii) WLL Wireless in Local Loop

(iv) TCP/IP Transmission Control Protocol/Internet Protocol

(½ Mark for each correct expansion)

(c) Which of the following units measures the speed with which data can be

transmitted from one node to another node of a network ? Also, give the

expansion of the suggested unit. 1

(i) KMph

(ii) Mbps

(iii) MGps

(c) (ii) Mbps

Mega bits per second

(½ Mark for correct identification)

(½ Mark for correct expansion)

(d) “Hindustan Connecting World Association” is planning to start their offices in

four major cities in India to provide regional IT infrastructure support in the

field of Education & Culture. The company has planned to set up their head

office in New Delhi in three locations and have named their New Delhi offices

as “Sales Office”, ”Head Office” and “Tech Office”. The company’s regional

offices are located at ”Coimbatore”, “Kolkata” and “Ahmedabad”.

A rough layout of the same is as follows :

Approximate distance between these offices as per network survey team

is as follows :

|Place From |Place To |Distance (Km) |

|Head Office |Sales Office |10 |

|Head Office |Tech Office |0.070 |

|Head Office |Kolkata Office |1291 |

|Head Office |Ahmedabad Office |790 |

|Head Office |Coimbatore Office |1952 |

In continuation of the above, the company experts have planned to install

the following number of computers in each of their offices :

|Head Office |100 |

|Sales Office |20 |

|Tech Office |50 |

|Kolkata Office |50 |

|Ahmedabad Office |50 |

|Coimbatore Office |50 |

(i) Suggest network type (out of LAN, MAN, WAN) for connecting each

of the following set of their offices :

• Head Office and Tech Office

• Head Office and Coimbatore Office

(i) · Head Office and Tech Office: LAN

· Head Office and Coimbatore Office: WAN

(½ Mark for mention of each - LAN and WAN correctly)

(ii) Which device will you suggest to be procured by the company for

connecting all the computers within each of, their offices out of the

following devices ?

• Modem

• Telephone

• Switch/Hub

(ii) · Switch/Hub

(1 Mark for the correct device)

(iii) Which of the following communication media, will you suggest to be

procured by the company for connecting their local offices in New

Delhi for very effective and fast communication ?

• Ethernet Cable

• Optical Fiber

• Telephone Cable

(iii) · Optical fiber

(1 Mark for the correct device)

(iv) Suggest a cable/wiring layout for connecting the company’s local offices

located in New Delhi. Also,, suggest an effective method/technology

for connecting the company’s regional offices at “Kolkata”,

“Coimbatore” and “Ahmedabad”.

(iv) Optical Fiber/Star Topology

Wireless

OR

Optical Fiber/Bus Topology

Wireless

(½ Mark for the correct layout)

(½ Mark for the any equivalent correct technology)

Or

YEAR 2007 (OUTSIDE DELHI)

7. (a) What is the significance of Cyber law ? 1

(a) Cyber law encompasses a wide variety of political and legal issues related to

the Internet and other communications technology, including intellectual

property, privacy, freedom of expression, and jurisdiction.

OR

Cyber law helps prevent Cyber Crime, Hacking, Data theft, Software Piracy

and protects rights of Cyber Users.

(1 Mark for any correct significance / explanation)

(b) Expand the following terms with respect to Networking : 2

(i) CDMA (iii) FTP

(ii) WLL (iv) HTML

(b) (i) Code Division Multiple Access

(ii) Wireless Local Loop

(iii) File Transfer Protocol

(iv) Hyper Text Markup Language

(½ Marks for each correct expansion)

(c) Which of the following unit measures the speed with which data can be

transmitted from one node to another node of a network? Also, give the

expansion of the suggested unit. 1

(i) Mbps

(ii) KMph

(iii) MGps

(c) (i) Mbps (Mega Bits Per Second)

(½ Marks for correct choice)

(½ Marks for correct expansion)

(d) “Bhartiya Connectivity Association” is planning to spread their offices in four

major cities in India to provide regional IT infrastructure support in the field

of Education & Culture. The company has planned to setup their head office

in New Delhi in three locations and have named their New Delhi offices as

“Front Office”, “Back Office” and “Work Office”. The company has three

more regional offices as “South Office”, “East Office” and “West Office”

located in other three major cities of India. A rough layout of the same is as

follows :

Approximate distance between these offices as per network survey team

is as follows :

|Place From |Place To |Distance (Km) |

|Back Office |Front Office |10 |

|Back Office |Work Office |0.070 |

|Back Office |East Office |1291 |

|Back Office |West Office |790 |

|Back Office |South Office |1952 |

In continuation of the above, the company experts have planned to install

the following number of computers in each of their offices :

|Back Office |100 |

|Front Office |20 |

|Work Office |50 |

|East Office |50 |

|West Office |50 |

| South Office |50 |

(i) Suggest network type (out of LAN, MAN, WAN) for connecting each

of the following set of their offices :

• Back Office and Work Office

• Back Office and South Office

(i) Back Office and Work Office – LAN

Back Office and South Office – WAN

(½ Mark for each correct answer)

(ii) Which device you will suggest to be procured by the company for

connecting all the computers with in each of their offices out of the

following devices?

• Switch/Hub

• Modem

• Telephone

(ii) Switch/Hub

(1 Mark for correct answer)

(iii) Which of the following communication medium, you will suggest to be

procured by the company for connecting their local offices in New

Delhi for very effective and fast communication?

• Telephone Cable

• Optical Fiber

• Ethernet Cable

(iii) Optical Fiber

(1 Mark for correct answer)

(iv) Suggest a cable/wiring layout for connecting the company’s local offices

located in New Delhi. Also, suggest an effective method/technology

for connecting the company’s regional offices-”East Office”, “West

Office” and “South Office” with offices located in New Delhi.

Satellite link between West Office, South Office and Back office

Optical Fibre between Front Office and Back Office

Ethernet cable between Back office and Work office

Or

Any other suitable layout / topology drawn or explained.

Optical Fibre/Star Topology

OR

Optical Fibre/Bus Topology

OR

Wireless

(½ Mark for the correct layout)

(½ Mark for the any equivalent correct technology)

Year 2006 (Delhi)

7.

(a) Differentiate between Internet and Intranet. 1

(a) Internet is a network of computer networks which operates world-wide

using a common set of communications protocols.

Intranet is an inter-connected network within one organization that uses Web

technologies for the sharing of information internally.

(Full 1 Mark for correctly defining internet only as Intranet is not

directly specified in the syllabus)

(b) Expand the following terms

(i) CDMA (ii) URL (iii) HTTP (iv) WAN 2

(b) (i) Code Divison Multiple Access

(ii) Uniform Resource Locator (Location) / Universal Resource Locator (Location)

(iii) Hype Text Transfer (Transmission) Protocol

(iv) Wide Area Network

( ½ mark for each term)

(c) Write one advantage of STAR topology as compared toTBUS topology. 1

(c) Fault detection is easy.

Fault isolation is easy.

OR

Any other valid advantage.

(1 mark for any one correct advantage)

(d) UNIVERSITY OF CORRESPONDENCE in Allahabad is setting up the

network between its different wings. There.are 4 wings named as Science (S),

Journalism (J), ARTS (A) and Home Science(H).

Distance between various wings are given below

Wing A to Wing S 100 m

Wing A to Wing J 200 m

Wing A to Wing H 400 m

Wing S to Wing J 300 m

Wing S to Wing H 100 m

Wing J to Wing H 450 m

Number of Computers

Wing A 150

Wirig S 10

Wing J 5

Wing H 50

(i)Suggest a suitable Topology for networking the computer of all wings 1

(d) (i) Star or Bus or any other valid topology or diagram.

(1 mark for mentioning any of the above topologies)

(1 mark for diagrammatic representation of any of the above topologies)

(ii) Name the wing where the Server to be installed. Justify your answer, 1

(ii) Wing A, because maximum number of computers are located at Wing A.

(1 mark for the correct answer)

OR

( ½ mark if only Wing A is mentioned without justification)

(iii) Suggest the placement of Hub/Switch in the network. 1

(iii) Hub/Switch in all the wings.

OR

Correct diagram depicting placement of Hub/Switch in all the wings.

(1 mark for correct placement)

(iv) Mention an economic technology to provide internet accessibility to all

wings.

(iv) Coaxial cable / Modem / LAN / TCP-IP / Dialup/ DSL/ Leased Line

OR any other valid technology (any one).

Note: Optical fiber, Satellite link and Microwave NOT to be

considered as valid answers.

(1 Mark for any valid technology)

| | |Year: 2006 (Outside Delhi) | |

|7 |(a) |Name two transmission media for networking. |1 |

| | |Ans.: | |

| | |Transmission media are: | |

| | | | |

| | |Optical Fiber | |

| | |Ethernet Cable or twisted pair cable or UTP or STP | |

| | |Co-axial Cable | |

| | |Infrared | |

| | |Radio Link OR Radiowave | |

| | |Microwave link OR Microwave | |

| | |Satellite Link | |

| | |[Any TWO of the mentioned above OR any other correct media] | |

| | |(1/2 Mark for each correct answer) | |

| |(b) |Expand the following terms: |2 |

| | |XML | |

| | |GSM | |

| | |SMS | |

| | |MAN | |

| | |Ans.: | |

| | |XML Extensible Markup Language | |

| | |GS M Global System for Mobile communication {ignore communication} | |

| | |SMS Short Messaging Service {Message/Messaging both acceptable} | |

| | |MAN Metropolitan Area Network | |

| | |(1/2 Mark for each correct answer) | |

| | |(No marks for partially correct answers) | |

| |(c) |Differentiate between Hackers and Crackers. |1 |

| | |Ans.: | |

| | |Hackers: Computer enthusiasts who enjoy learning about computer systems and get into other system/network | |

| | |for gaining more knowledge or may find flaws in the system for rectification purposes. | |

| | |Crackers: Malicious programmers who break into secure systems for stealing and corrupting/spoiling data. | |

| | |(1/2 Mark for definition of each Hacker and Cracker) | |

| | |OR | |

| | |(Full 1 Mark for mentioning the difference) | |

| |(d) |Indian Public School in Darjeeling is setting up the network between its different wings. There are 4 | |

| | |wings named as SENIOR(S), JUNIOR(J), ADMIN(A) and HOSTEL(H). | |

| | |Distance between various wings are given below: | |

| | | | |

| | |Wing A to Wing S | |

| | |100 m | |

| | | | |

| | |Wing A to Wing J | |

| | |200 m | |

| | | | |

| | |Wing A to Wing H | |

| | |400 m | |

| | | | |

| | |Wing S to Wing J | |

| | |300 m | |

| | | | |

| | |Wing S to Wing H | |

| | |100 m | |

| | | | |

| | |Wing J to Wing H | |

| | |450 m | |

| | | | |

| | | | |

| | |Number of Computers | |

| | |Wing A | |

| | |10 | |

| | | | |

| | |Wing S | |

| | |200 | |

| | | | |

| | |Wing J | |

| | |100 | |

| | | | |

| | |Wing H | |

| | |50 | |

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| | | | |

| | |Suggest a suitable topology for networking the computer of all wings. |1 |

| | |Name the wing where the Server is to be installed. Justify your answer. | |

| | |Suggest the placement of Hub/ Switch in the network. |1 |

| | |Mention an economic technology to provide internet accessibility to all wings. | |

| | |Ans: (i) Star Topology OR Bus Topology |1 |

| | |(1 Mark for mentioning any one of the two topologies) OR |1 |

| | |(1 Mark for diagramatic representation of any of the above mentioned topologies) | |

| | | | |

| | | | |

| | |100 m | |

| | |100 m | |

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| | |400 m | |

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| | |200 m 300 m 450 m | |

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| | |The bus topology can be used for the above layout as follows: | |

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| | |(ii) Wing S as it has the maximum number of computers | |

| | |OR | |

| | |Wing A as it is placed in the Admin Wing (for security reasons) | |

| | |(1/2 Mark for identification of the correct Wing) | |

| | |(1/2 Mark for correct justification) . | |

| | |Inside all the four wings | |

| | |(1 Mark for the correct answer) | |

| | |Any one of the following: | |

| | |Dialup, TCP/IP, DSL, Modem, Broadband, Cable, ISDN, Telephone | |

| | |Line, Co-axial, Ethernet Cable, Radiowave | |

| | |(1 Mark for the correct answer) | |

| | |Important Note: Satellite Link, Optical Fiber, Microwave and | |

| | |Leased line are not acceptable solution for this question | |

| | | | |

| | | | |

| | |(Radio Wave : The most economic way to connect with a reasonable high speed would be to us radio wave | |

| | |transmission as they are easy to install, can travel long distances and penetrate buildings easily so they| |

| | |are widely used for communications both indoors and outdoors. Radio waves also have the advantage of being| |

| | |omni directional which is they can travel in all the directions form the source so that transmitters and | |

| | |receivers do not have to be carefully aligned physically.) | |

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| | |Year 2005 (Delhi) | |

|7 |(a) |What is the difference between Message Switching technique and Packet Switching technique? |1 |

| | |Ans: | |

| | |Message switching: | |

| | |The saurce computer sends data (message) to the | |

| | |switching office, which stores data in a buffer. It then looks for a free link to another switching office| |

| | |and sends data to that office. This process continues until data is delivered to the destination computer.| |

| | |This type of switching technique is also known as ‘store and forward’ switching. | |

| | | | |

| | |[pic] | |

| | | | |

| | |Packat switching: | |

| | |A fixed size of packet that can be transmitted across the network is specified. All the packets are stored| |

| | |in the main memory instead of disk. As a result accessing time of packets is reduced. | |

| | | | |

| | |[pic] | |

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| | |[½ Mark for defining each of them] | |

| | |OR | |

| | |[½ Mark for diagrammatic representation of each of them] | |

| |(b) |(b) Expand the following terminologies : |2 |

| | |(i) TCP/IP | |

| | |(ii) XM L | |

| | |(iii) CDMA | |

| | |(iv) WLL | |

| | | | |

| | |Ans: | |

| | |(i) Tranmission Control Protocol/Internet Protocol | |

| | |(ii) eXtensible Markup Language OR extendable Markup Language | |

| | |(iii) Code Division Multiple Access | |

| | |(iv) Wireless in a Local Loop | |

| | |[½ Mark for expanding each of them] | |

| |(c) |Write two application of Cyber Law. |1 |

| | |Ans.: Cyber law encompasses a wide variety of political and legal issues related to the Internet and other| |

| | |communications technology, including intellectual property, privacy, freedom of expression, and | |

| | |jurisdiction. | |

| | |[1 Mark for writing any one correct application] | |

| |(d) |The Great Brain Organisation has set up its new Branch at Srinagar for its office | |

| | |and web based activities. It has 4 Wings of buildings as shown in the diagram : | |

| | | | |

| | | | |

| | |[pic] | |

| | | | |

| | |Center to center distances between various blocks | |

| | |Wing X to Wing Z 50m | |

| | |Wing Z to Wing Y 70m | |

| | |Wing Y to Wing X 125m | |

| | |Wing Y to Wing U 80m | |

| | |Wing X to Wing U 175m | |

| | |Wing Z to Wing U 90m | |

| | | | |

| | | | |

| | |Number of Computers | |

| | |Wing X 50 | |

| | |Wing Z 30 | |

| | |Wing Y 150 | |

| | |Wing U 15 | |

| | |Suggest a most suitable cable layout of connections between the Wings, and topology. | |

| | |Ans: [½ Mark for drawing / mentioning any suitable cable layout] | |

| | |[½ Mark for mentioning the topology] | |

| | | | |

| | |Suggest the most suitable place (i.e. Wing) to house the server of this organization with a suitable | |

| | |reason, with justification. | |

| | |Ans: Wing Y as it has largest number of computers | |

| | |[½ Mark for mentioning Wing Y] | |

| | |[½ Mark for suitable justification] | |

| | | | |

| | | |1 |

| | |(iii) Suggest the placement of the following devices with justification: | |

| | |(1) Repeater | |

| | |(2) Hub/Switch | |

| | | | |

| | |Ans: |1 |

| | |[½ Mark for mentioning Switch/Hub placement in each of the | |

| | |building] | |

| | |[½ Mark for suggesting the placement of repeater for the | |

| | |distances higher than 70 m] | |

| | | | |

| | |The organization is planning to link its head office situated in Delhi with the offices at Srinagar. | |

| | |Suggest an economic way to connect it; the company is ready to compromise on the speed of connectivity. |1 |

| | |Justify your answer. | |

| | | | |

| | |Ans: | |

| | |TCP/IP Dial Up (Most Suitable answer 1) | |

| | |OR | |

| | |Telephone Link (Most Suitable answer 2) | |

| | |OR | |

| | |Microwave | |

| | |OR | |

| | |Radio Link/Radio Wave | |

| | |OR |1 |

| | |Satellite Link | |

| | |OR | |

| | |WAN | |

| | |[½ Mark for mentioning any of the above] | |

| | |[½ Mark for giving any suitable reason for any of the above] | |

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| | |Year: 2005 (Outside Delhi) | |

|7 |(a) | Compare Optical Fiber and Co-axial transmission media. |1 |

| | |Optical Fibre | |

| | |Co axial Cable | |

| | | | |

| | |These cables are made of plastic and glass and are about as thick as human hair.These cables are highly | |

| | |durable and of offer excellent performance but are expensive | |

| | |A coaxial cable consist of one or more small cables in a protective covering. | |

| | |They are less expensive compared to optical fibres. | |

| | | | |

| | |Installation: Very Hard | |

| | |Installation: Easy | |

| | | | |

| | |Interference : It is immune to electric and magnetic interference i.e. noise in any form because the | |

| | |info. Is traveling on a modulated beam | |

| | |Interference: Low or moderate interference. | |

| | | | |

| | |Bandwidth : 100 Mbps - 2 Gbps | |

| | |Bandwidth : 10 Mbps | |

| | | | |

| | |Max. Segment Length: 2Km – 100 Km | |

| | |Max. Segment Length:185m – 500m | |

| | | | |

| | |Types: Multi-Node, Single Node | |

| | |Types: Thinnet , Thicknet | |

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| | | | |

| | |From CBSE marking scheme:- | |

| | | | |

| | |Coaxial Cable: | |

| | |Comparatively Slow, Economic, convenient to lay down, | |

| | |used in Bus topology of networks; | |

| | |Optical Fibre: | |

| | |Very fast, expensive, reliable, no interference | |

| | |(1 Mark for mentioning any one valid difference) | |

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| |(b) |Expand the following terminologies: |1 |

| | |HTML | |

| | |GSM | |

| | | | |

| | |HTML :- Hypertext Markup Language | |

| | |GSM :- Global System for Mobile Communication | |

| | |(½ Mark for each correct expansion) | |

| |(c) |What is the difference between XML and HTML? Write two differences. |1 |

| | | | |

| | |XML (eXtensible Markup Language) | |

| | |HTML (Hyper Text Markup Language) | |

| | | | |

| | |It contains user defined tags | |

| | | | |

| | |XML neither specifies neither semantic or tag set. | |

| | |It contains predefined tags | |

| | | | |

| | |In HTML both tag semantics and tag set are fixed. | |

| | | | |

| | |XML is markup language for documents containing structural info. | |

| | |HTML is just a page layout and hyperlink specification language. | |

| | | | |

| | | | |

| | |(1 Mark for mentioning the difference) | |

| | |OR | |

| | |(½ Mark for only expansions of XML and HTML) | |

| |(d) |What do you understand by the terms Cookies and Firewall? |1 |

| | |Cookies: | |

| | |A small piece of information that a server sends to a client When | |

| | |you visit a Web site with cookie capabilities, its server sends certain information about you to your | |

| | |browser, which is stored on your hard drive as a text file. At some later time (such as returning to the | |

| | |site the next day), the server retrieves the cookie. It’s a way to the server to remember things about | |

| | |you. | |

| | |Firewall: | |

| | |Any of a number of security schemes (hardware/software) that | |

| | |prevent unauthorized users from gaining access to a computer network or that monitor transfers of | |

| | |information to and from the network. | |

| | |(½ Mark each for mentioning the key terms from the above or | |

| | |equivalent) | |

| |(e) |The Cyber Mind Organization has set up its new Branch at Mizoram for its office and web based activities. | |

| | |It has 4 wings of buildings as shown below in the diagram: | |

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| | |Center to center distance between various blocks: | |

| | | | |

| | |Wing X to wing Z | |

| | |40m | |

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| | |Wing Z to Wing Y | |

| | |60m | |

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| | |Wing Y to Wing X | |

| | |135m | |

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| | |Wing Y to Wing U | |

| | |70m | |

| | | | |

| | |Wing X to Wing U | |

| | |165m | |

| | | | |

| | |Wing Z to Wing U | |

| | |80m | |

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| | |Number of Computers: | |

| | |Wing X | |

| | |50 | |

| | | | |

| | |Wing Z | |

| | |130 | |

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| | |Wing Y | |

| | |40 | |

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| | |Wing U | |

| | |15 | |

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| | |(e1) Suggest a most suitable cable layout of connection between the wings and topology. | |

| | | | |

| | |Ans.: | |

| | |Layout 1: Bus topology | |

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| | |Layout 2: Star Topology | |

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| | |1 Mark to every one irrespective of attempt | |

| | |(e2) Suggest the most suitable place (i.e. Wing) to house the server of this organization with a suitable |1 |

| | |reason with justification. | |

| | |Ans: Wing Z as it has largest number of computers | |

| | |(½ Mark for mentioning Wing Z) | |

| | |(½ Mark for suitable justification) | |

| | |(e3) Suggest the placement of the following devices with justification: |1 |

| | |Repeater | |

| | | | |

| | |Hub/Switch | |

| | | | |

| | |(i) Repeater: For layout 1 repeater can be used between wing Y and wing U and between wing Z and wing Y. | |

| | |And in layout 2 the repeater can be used between wing Z and wing U and between wing Z and wing Y. | |

| | |Repeater is used to avoid loss of signals during the course of data flow in these roots. | |

| | |In both the layouts a hub or switch would be needed in all the blocks to interconnect the group of cables | |

| | |fro the diff. computers in each wing. | |

| | | | |

| | |(Full 1 Mark for mentioning Switch/Hub placement in each of | |

| | |the building) | |

| | |OR | |

| | |(Full 1 Mark for suggesting the placement of repeater for the | |

| | |distances higher than 70 m) | |

| | |(e4) The organization is planning to link its head office situated in Delhi with the offices at Mizoram. |1 |

| | |Suggest an economic way to connect it; the company is ready to compromise on the speed of connectivity. | |

| | |Justify your answer. | |

| | | | |

| | |Ans: TCP/IP Dial Up (Most Suitable answer 1) | |

| | |OR | |

| | |Telephone Link (Most Suitable answer 2) | |

| | |OR | |

| | |Microwave | |

| | |OR | |

| | |Radio Link/Radio Wave | |

| | |OR | |

| | |Satellite Link | |

| | |OR | |

| | |WAN | |

| | |(½ Mark for mentioning any of the above) | |

| | |(½ Mark for giving any suitable reason for any of the above) | |

| | |2004 | |

|7 |(a) |Write two advantages and two disadvantages for STAR topology. |1 |

| | |Ans.: Star Topology : Advantages :- | |

| | |Centralized Control or problem diagnosis. | |

| | |Simple access protocol. | |

| | |Ease of service. | |

| | |One device per connection. | |

| | | | |

| |(b) |Write one different between coaxial and optical cable. |1 |

| | |Optical Fibre | |

| | |Co axial Cable | |

| | | | |

| | |These cables are made of plastic and glass and are about as thick as human hair. These cables are highly | |

| | |durable and of offer excellent performance but are expensive | |

| | |A coaxial cable consist of one or more small cables in a protective covering. | |

| | |They are less expensive compared to optical fibres. | |

| | | | |

| | |Installation: Very Hard | |

| | |Installation: Easy | |

| | | | |

| | |Interference : It is immune to electric and magnetic interference i.e. noise in any form because the | |

| | |info. Is traveling on a modulated beam | |

| | |Interference: Low or moderate interference. | |

| | | | |

| | |Bandwidth : 100 Mbps - 2 Gbps | |

| | |Bandwidth : 10 Mbps | |

| | | | |

| | |Max. Segment Length: 2Km – 100 Km | |

| | |Max. Segment Length:185m – 500m | |

| | | | |

| | |Types: Multi-Node, Single Node | |

| | |Types: Thinnet , Thicknet | |

| | | | |

| |(c) |Explain the following terms in short: |2 |

| | |FTP | |

| | | | |

| | |URL | |

| | | | |

| | |7c) FTP(File Transfer Protocol) :- FTP allows the transferring of files from one system to another on | |

| | |the internet. File of any type can be transferred although you may have to specify whether the file is | |

| | |ASCII or binary. They can be transferred to any system on the internet provided that permissions are set | |

| | |accordingly. It promotes sharing of files. | |

| | | | |

| | |URL(Uniform Resource Locator) :- Specifies the distinct address for each resource on the internet. An | |

| | |internet address which is character based is called a domain name. | |

| | |HTTP uses internet address in a specified format called URL. URL’s look like this type://address/path | |

| | |where type specifies the type of server in which the file is located, address is address of server for | |

| | |example in the following URL | |

| | |HTTP specifies the type of server and what is the .com part is the address of the server and remaining | |

| | |part is path of the file. | |

| | | | |

| |(d) |Define Packet Switching |1 |

| | |Ans.: Data Packet Switching: - Switching technique transmits data in form of packets (block of data) of | |

| | |fixed size is known as packet switching. All the packets of fixed size are stored in main memory which | |

| | |improves the performance as access time is reduced. | |

| | |2003 | |

|7 |(a) |What is the purpose of using a repeater in the context of networking? |1 |

| | |Repeater :- 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 cable connecting a network lose the signal transmitted. If the signal degrades to much | |

| | |it fails to reach the destination. Or if it does arrive the degradation of the message makes it useless. | |

| | |Repeaters can be installed along the way to ensure that data packets reach their destination. | |

| |(b) |Write an advantage and a disadvantage of using optical fiber cables. |1 |

| | |Ans.: | |

| | |Advantage: It is immune to electric and magnetic interference i.e. noise in any form because the info. Is| |

| | |traveling on a modulated beam | |

| | | | |

| | |Disadvantage: They are the most expensive of all the cables and are difficult to solder. | |

| |(c) |Write one advantage and one disadvantage of the following topologies in network: |2 |

| | | | |

| | |BUS Topology | |

| | | | |

| | |STAR Topology | |

| | | | |

| | |Bus Topology | |

| | |Star Topology | |

| | | | |

| | |Advantages :- a) Short Cable length and simple wiring layout. | |

| | |b) Resilient architecture. | |

| | |c) Easy to extend. | |

| | |Advantages:- a) Centralized Control and problem diagnosis. | |

| | |b) Ease of Service. | |

| | |c) One device per connection. | |

| | |d) Simple access protocol. | |

| | | | |

| | |Disadvantages :- a) Fault diagnosis and isolation is difficult. | |

| | |b) Repeater configuration. | |

| | |Disadvantages :- a) Central node dependency. | |

| | |b) Long cable length. | |

| | |c) Difficult to expand. | |

| | | | |

| | | | |

| | | | |

| | | | |

| |(d) |What is the difference between MAN and WAN? |1 |

| | |MAN(Metropolitan Area Network) | |

| | |WAN(Wide Area Network) | |

| | | | |

| | |MAN are networks spread over a city ex. Cable TV network that are spread over a city can be termed as MAN.| |

| | |The network spread across countries are known as WAN.WAN is a group of computers that are separated by | |

| | |large distances and are tied together. The internet is the largest WAN. | |

| | | | |

| | | | |

| | |2002 | |

|7 |(a) |What is a MODEM? |1 |

| | |MODEM:- A modem is a computer peripheral that allows you to connect and communicate with other computer | |

| | |via telephone lines. Telephone lines cannot carry digital information, a MODEM changes digital data from | |

| | |computer into analog data, a format that can be carried by telephone lines. In a similar manner the modem | |

| | |receiving the data then changes analog signal back into digital data that computer can process. This is | |

| | |called Modulation Demodulation. | |

| |(b) |Write the following abbreviation in their full form. |1 |

| | |FTP | |

| | |WAN | |

| | |WWW | |

| | | | |

| | |Ans.: | |

| | |FTP:- File Transfer Protocol | |

| | |WAN: Wide Area Network | |

| | |WWW: World Wide Web | |

| |(c) |Mention one difference between circuit switching and packet switching. |2 |

| | | | |

| | |Circuit Switching | |

| | |Packet 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. | |

| | |In this a fixed size of packet which can be transmitted across the network is specified. All the packets | |

| | |of fixed size are stored in main memory. This improves the performance as the access time is reduces. If | |

| | |follows store and forward principle for packet. | |

| | | | |

| | | | |

| |(d) |Write two advantages and disadvantages of the following topologies in network: |1 |

| | |Bus | |

| | |Ring | |

| | |Ans.: | |

| | |Bus | |

| | |Ring | |

| | | | |

| | |Advantages: | |

| | |1. Short cable length and simple wiring layout. | |

| | | | |

| | |1. Short cable length. | |

| | | | |

| | |2. Easy to extend. | |

| | |2. No wiring closet space required. | |

| | | | |

| | |Disadvantages: | |

| | |1.Fault diagnosis is difficult | |

| | | | |

| | |1. Node failure causes network failure. | |

| | | | |

| | |2. Fault isolation is difficult. | |

| | |2. Difficult to diagnose fault. | |

| | | | |

| | |3. Nodes must be intelligent. | |

| | |3. Network reconfiguration is difficult. | |

| | | | |

| | |4. Repeater configuration. | |

| | | | |

| | | | |

| | | | |

| | |2001 | |

|7 |(a) |What is NFS? |1 |

| | |Ans: Network File System (NFS) is a protocol originally developed by Sun Microsystems in 1984 and defined | |

| | |as a distributed file system which allows a computer to access files over a network as easily as if they | |

| | |were on its local disks. NFS is one of many protocols built on the Open Network Computing Remote Procedure| |

| | |Call system (ONC RPC). | |

| |(b) |Mention one advantage of networking. |1 |

| | |Ans.: Advantages of networking are: | |

| | |Resource sharing | |

| | |Access to remote databases | |

| | |Communication facilities | |

| |(c) |Name two communication channels used in networking and explain any one. |2 |

| | |Ans.: Communication channels are : Twisted Pair Cable, Coaxial Cable, Optical Fibers, Microwave, Radio | |

| | |Wave, Satellite etc. (any 2) | |

| | |Optical Fibers: It consists 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 light sources | |

| | |used are either light emitting diodes (LEDs) or Laser Diodes (LDs). The data to be transmitted is | |

| | |modulated onto the light beam using frequency modulation techniques. The signals can then be picked up at | |

| | |the receiving end and demodulated. The band width of the medium is potentially very high. For LEDs this | |

| | |ranges between 20 and 150 mbps and higher rates are possible using LDs. | |

| | | | |

| | |The Fiber Optic consists of three pieces : | |

| | |core | |

| | |cladding | |

| | |protective coating | |

| |(d) |Mention one difference between Linear (bus) and Star topologies in networking. |1 |

| | | | |

| | |Bus Topology | |

| | |Star Topology | |

| | | | |

| | |Advantages :- a) Short Cable length and simple wiring layout. | |

| | |b) Resilient architecture. | |

| | |c) Easy to extend. | |

| | |Advantages:- a) Centralized Control and problem diagnosis. | |

| | |b) Ease of Service. | |

| | |c) One device per connection. | |

| | |d) Simple access protocol. | |

| | | | |

| | |Disadvantages :- a) Fault diagnosis and isolation is difficult. | |

| | |b) Repeater configuration. | |

| | |Disadvantages :- a) Central node dependency. | |

| | |b) Long cable length. | |

| | |c) Difficult to expand. | |

| | | | |

| | | | |

| | |2000 | |

|7 |(a) |What are repeaters? |1 |

| | |Ans.: A Repeater is a network device that amplifies and restores signals for long distance transmission. | |

| | |It used in long network lines which exceed the maximum rated distance for a single run. | |

| |(b) |Name the device used to connect a computer to an analog telephone line. |1 |

| | |Ans. : MODEM | |

| |(c) |Briefly mention two advantages and two disadvantages of star topology in network. |2 |

| | | | |

| | |Star Topology | |

| | | | |

| | |Advantages:- a) Centralized Control and problem diagnosis. | |

| | |b) Ease of Service. | |

| | |c) One device per connection. | |

| | |d) Simple access protocol. | |

| | | | |

| | |Disadvantages :- a) Central node dependency. | |

| | |b) Long cable length. | |

| | |c) Difficult to expand. | |

| | | | |

| |(d) |What is the difference between MAN and WAN? |1 |

| | | | |

| | | | |

| | | | |

| | |Ans.: | |

| | |MAN | |

| | |WAN | |

| | | | |

| | |1. Diameter of not more than a few kilometers. | |

| | |Span entire countries. | |

| | | | |

| | |2. A total data rate of at least several Mbps | |

| | |Data rate less than 1 Mbps | |

| | | | |

| | |3. Complete ownership by a single organization. | |

| | |Owned by multiple organizations. | |

| | | | |

| | |4.Very low error rates. | |

| | |Comparatively higher error rates. | |

| | | | |

| | |1999 | |

|7 |(a) |What are Gateways? |1 |

| | |Ans.: 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. | |

| |(b) |What is the purpose of using a bridge? |1 |

| | |Ans.: | |

| | |A Bridge is a network device that establishes an intelligent connection between two local networks with | |

| | |the same standard but with different types of cables. | |

| | | | |

| | |A Bridge is a device that links two networks together. Bridges are marts enough to know which computers | |

| | |are on which side of the bridge, so that they only allow those messages that need to get to the other side| |

| | |to cross the bridge. This improves the performance on both sides of the bridge. As a packet arrives at the| |

| | |bridge, the bridge examines the physical destination address destination address of the packet. The bridge| |

| | |then decides whether or not to let the packet cross. | |

| |(c) |Give two advantages and two disadvantages of the following network topologies: |2 |

| | | | |

| | |Bus | |

| | | | |

| | |Star | |

| | | | |

| | | | |

| | |Bus Topology | |

| | |Star Topology | |

| | | | |

| | |Advantages :- a) Short Cable length and simple wiring layout. | |

| | |b) Resilient architecture. | |

| | |c) Easy to extend. | |

| | |Advantages:- a) Centralized Control and problem diagnosis. | |

| | |b) Ease of Service. | |

| | |c) One device per connection. | |

| | |d) Simple access protocol. | |

| | | | |

| | |Disadvantages :- a) Fault diagnosis and isolation is difficult. | |

| | |b) Repeater configuration. | |

| | |Disadvantages :- a) Central node dependency. | |

| | |b) Long cable length. | |

| | |c) Difficult to expand. | |

| | | | |

| |(d) |What is the difference between LAN and MAN? |1 |

| | |Ans.: | |

| | |LAN | |

| | |MAN | |

| | | | |

| | |Small computer networks that are confined to localized area (e.g. an office, a building or a factory) are | |

| | |known a LANs(Local Area Networks). | |

| | |Metropolitan Area Networks are the networks spread over a city. For example, cable TV network that are | |

| | |spread over a city. | |

| | | | |

| | |The hardware as well as software resources are shared through LANs. | |

| | |The purpose of the MAN is also the sharing of hardware and software resources among its users. | |

| | | | |

| | | | |

| | |1998- Delhi | |

|7 |(a) |What are repeaters? | |

| |(b) |What is the difference between LAN and MAN? | |

| |(c) |Describe the following in brief: | |

| | |MOSAIC | |

| | |Usenet | |

| |(d) |What do you understand by a backbone network? | |

| | |1998-Outside Delhi | |

|7 |(a) |What are Routers? |1 |

| | |Ans.: | |

| | |A Router is a network device that is used to separate different segments in a network to improve | |

| | |performance and reliability. A router works like a bridge but can handle different protocols. | |

| |(b) |What is the purpose of using MODEM? |1 |

| | |Ans.: | |

| | |As ordinary telephone lines cannot carry digital information, MODEM changes the digital data from the | |

| | |computer into analog data, a format that can be carried by telephone lines. In a similar manner, the MODEM| |

| | |receiving the call, changes the analog signal back into digital data that can be processed by the | |

| | |computer. | |

| |(c) |Write the two advantages and two disadvantages of the following topologies in network: |2 |

| | | | |

| | |Bus Topology | |

| | | | |

| | |Star Topology | |

| | | | |

| | |Bus Topology | |

| | |Star Topology | |

| | | | |

| | |Advantages :- a) Short Cable length and simple wiring layout. | |

| | |b) Resilient architecture. | |

| | |c) Easy to extend. | |

| | |Advantages:- a) Centralized Control and problem diagnosis. | |

| | |b) Ease of Service. | |

| | |c) One device per connection. | |

| | |d) Simple access protocol. | |

| | | | |

| | |Disadvantages :- a) Fault diagnosis and isolation is difficult. | |

| | |b) Repeater configuration. | |

| | |Disadvantages :- a) Central node dependency. | |

| | |b) Long cable length. | |

| | |c) Difficult to expand. | |

| | | | |

| |(d) |What is the difference between LAN and Internet? |1 |

| | |Ans.: | |

| | |LAN | |

| | |Internet | |

| | | | |

| | |1. Diameter of not more than a few kilometers. | |

| | |Span entire countries. | |

| | | | |

| | |2. A total data rate of at least several Mbps | |

| | |Data rate less than 1 Mbps | |

| | | | |

| | |3. Complete ownership by a single organization. | |

| | |Owned by multiple organizations. | |

| | | | |

| | |4. Very low error rates. | |

| | |Comparatively higher error rates. | |

| | | | |

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Wing Z

Wing Y

Wing X

Wing U

Wing X

Wing Z

Wing Y

Wing U

Wing X

Wing Z

Wing Y

Wing U

Wing S

200

Wing A

10

Wing H

50

Wing J

100

Wing A

10

Wing H

50

Wing S

200

Wing J

100

Finance Unit

Corporate Unit

Delhi

INDIA

Chennai

Production Unit

Media

Unit

Back Office

Research Lab

Pondicherry

Corporate Unit

Mumbai

Development Unit

INDIA

New Delhi

Head Office

Sales Office

Sales Office

Tech Office

Tech Office

New Delhi

Sales Office

Head Office

INDIA

New Delhi

Kolkata Office

Ahemdabad

Office

Tech Office

Corporate Office

Head Office

INDIA

New Delhi

Back

Office

Front

Office

Work

Office

West

Office

East

Office

South

Office

INDIA

New Delhi

Back

Office

Front

Office

Work

Office

West

Office

East

Office

South

Office

Block A

Block C

Block D

Block B

Block C

Block A

Block B

Block D

Block A

Block C

Block B

Block D

Block A

Block C

Block B

Block D

Repeater

Repeater

Block A

Block C

Block B

Block D

Repeater

Block A

Block C

Repeater

Hub

Hub

Block D

Repeater

Block B

Hub

Hub

Block C

Block A

Repeater

Hub

Hub

Block D

Block B

Hub

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Building

Jazz

Building

Harsh Building

Raj Building

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Building

Harsh Building

Jazz

Building

Raj Building

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Building

Harsh Building

Jazz

Building

Training

Building

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Building

Resource

Building

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Building

Training

Building

Main

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Building

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Building

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Building

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Building

Resource

Building

Main

Building

Training

Building

Accounts

Building

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Building

Main

Building

Training

Building

Accounts

Building

Resource

Building

Main

Building

Training

Building

Accounts

Building

Resource

Building

Main

Building

Training

Building

Accounts

Building

Repeater

Repeater

Repeater

Hub

Hub

Hub

Hub

Hub

Hub

Hub

Hub

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