Summary of LAN hardware for the network design:
LAN network
To connect
two
computers
To connect
two
computers
over long
distances
To connect
more than
two
computers
To connect
more than
two
computers in
small
network
which can
filter traffic.
For large
network .
LAN
hardware
NIC
Repeater
Description
Problem
Network interface card for
connecting two computers
on LAN
Extends the distance
limitations of Ethernet
cable by boosting the signal
Cannot connect over
long distances
Hub
hub is a multiport device
for building starconfigured topologies with
twisted-pair cable
Bridge
Provides repeater functions
along with selective
filtering of traffic to reduce
congestion and contention
Switches
Basically a multiport bridge
that segments a network
into many smaller collision
domains while maintaining
the broadcast
characteristics. Greatly
improves the performance
of LANs
Only two computers
can be connected if you
want to connect more
computers then it is a
problem
 It cannot filter
traffic
 It is confined to
small network
 maximum nodes
can be 30
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Bridges have
limited ports
It introduce latency
for large networks.
Here network
traffic travels to all
LAN segments
without knowing
the exact IP
address of the
destination
segment.
It controls collision
domains but not
broadcast domains.
For
Router
internetworks
( connecting
more than
one LAN
network with
high speed
and
flexibility)
Routers make forwarding
decisions based on network
layer addresses.
………………………….
In addition to controlling
collision domains, routers
control broadcast domains
Switching:
Circuit-switching networks
In this technique, first the complete physical connection between two computers is
established and then data are transmitted from the source computer to the destination
computer
 Dedicated paths are used between source and destination.
 no queuing
 Example: telephone systems.
Message Switching
In this technique, the source computer sends data or the message to the switching office
first, which stores the data in its buffer. It then looks for a free link to another switching
office and then sends the data to this office. This process is continued until the data are
delivered to the destination computers. Owing to its working principle, it is also known
as store and forward. That is, store first (in switching office), forward later, one jump at
a time.

The network receives the entire messages, stores them in a
Secondary storage and transmit them.
 It provides long term storage even after the message has
been delivered.
Example:
 Hop-by-hop Telex forwarding and UUCP are examples of message switching
systems.
E-mail is another example of a message switching system
Packet Switching
. In packet switching no fixed path is created between devices that communicate; it is
broken into packets, each of which may take a separate path from sender to recipient.
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The message is divided into a number of slices called
Packets of certain fixed size.
Each packet has its destination address.
Queuing involved
Routing is needed
errors involved
Example: when you connect to the Internet using a dial-up modem.
Network topologies:
In Computer Networking “topology” refers to the layout or design of the connected
devices.
Topology can be classified into two :
 1-D (bus)
 2-D (tree, stars, rings, mesh, etc.)
13.8.1
Point to Point Topology
Point to Point topologies are simplest and most straightforward. Point-to-point (PTP)
topology connects two nodes directly together You can think of as a chain of devices
and another name for this type of connectivity is called daisy chaining. Most computers
can 'daisy chain' a series of serial devices from one of its serial ports. Networks of
routers are often configured as point-to-point topologies.
The following examples are pure point to point links:
Two computers communicating via modems.
A mainframe terminal communicating with a front end processor.
A workstation communicating along a parallel cable to a printer.
Advantage:
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It is easy to set up
Installation Cost is low
Fault identification is easy
Allows flexibility in communication hardware, packet formats, etc.
Provides security and privacy because communication channel is not
shared
Disadvantages
 Number of wires grows as square of number of computers
 Connections between buildings can be prohibitive
 Adding a new computer requires N - 1 new connections
13.8.2
Linear Bus
A linear bus topology consists of a main run of cable with a terminator at each end . All
nodes (file server, workstations, and peripherals) are connected to the linear cable.
Access and control of bus networks are typically maintained by a method called
contention, whereby if a line is unused, a terminal or device can transmit its message at
will, but if two or more terminals initiate messages simultaneously, they must stop and
transmit again at different intervals
Fig. 1. Linear Bus topology
Advantages of a Linear Bus Topology
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
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The advantage of the Bus network is that if one computer fails in the network the
others are still not affected and they continue to work.
Bus network is very simple and easy to set up. If there is an urgent need to set
up a network and perhaps be used on a short term basis then the Bus network is
the best possibility.
Bus networks use the least amount of cable to set up making it cost effective.
Disadvantages of a Linear Bus Topology
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Entire network shuts down if there is a break in the main cable.
Terminators are required at both ends of the backbone cable.
Difficult to identify the problem if the entire network shuts down.
Not meant to be used as a stand-alone solution in a large building.
13.8.3
Star Topology
A star topology consists of a central connection hub to which devices are connected
with UTP (Unshielded Twisted Pair) Ethernet. Contrary to the bus topology, a star
topology utilizes a point-to-point connection to connect each node to the central hub.
The hub acts as a signal booster as well, and all the data traffic that transverses the
network
passes
through
this
hub.
The entire network is dependent upon the central hub in a star topology, so if the entire
network is not working, it means that there is problem in the hub. This makes it easy to
troubleshoot the network because of the only one point for error correction. As all the
computers in star topology are independent to each other and dependent only on the
central hub, network failure or other network problems are less likely to happen. The
privacy of each of the computers is also maintained in this topology.
In star topology, new devices and nodes can be easily added and by just extending a
cable
from
the
hub.
Advantages of star topology:
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
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A star topology is simple in functionality and easy to manage.
If a problem occurs in the network, it can be easily isolated and cleared.
It is very easy to expand the star topology because of its simple format.
Disadvantages of star topology:
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
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The entire network of the star topology is completely dependent on the hub. If
the hub fails, the whole network fails.
Network connection may slow down when the number of nodes increases or
the cable lengthens.
Star topology needs more cable length than other topologies.
It is more expensive compared to bus topology.
Star Topology
13.8.4
Ring Topology
A ring topology consists of network of computers in which each node connects to
exactly two other nodes. This forms a single continuous path for the flow of signals
through each nodes of the network. Data travels from node to node, with each node
along the way handling every packet. Each of the nodes in the ring topology are
connected to each other through only one pathway, so the failure of only one link
disrupts
the
whole
network.
To overcome this fallacy, the data in a ring topology is transmitted both clockwise and
counter clockwise, so that if there is single break of the cable, all the nodes on both sides
can
be
reached.
Ring Topology
Advantages of Ring Topology
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It is an orderly network in which all the nodes in the network have equal access
to all the resources.
Its performance is far better compared to star topology under heavy network.
It does not need network servers to manage the connections.
Disadvantages of Ring Topology
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
If one of the workstations fails to operate, it may lead to the unusability of the
whole network.
Addition and removal of devices in the network can affect the entire network.
Ring network is slower than the Ethernet network.
13.8.5
Tree topology
A tree topology consists of bus and star topologies framed in a common network. The
tree like structure of this network allows the colleges, schools, universities and other
institutions to maintain their own network as a branch of a bigger network through
which they can maximize their area of access to the network. This type of network
topology is most suitable for such networks which are widely spread and divided into
many
branches.
On tree topology the hubs of each smaller topologies are connected to the central hub
that controls the entire network. However, some nodes can be directly connected to the
central
hub.
Tree topology
Advantages of tree topology
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

It is possible to form a point to point connection with tree topology.
All the computers can access other computers which are in other larger and
immediate networks.
Tree topology is best suited for branched out networks.
Disadvantages of tree topology

In this topology, the length of the network depends on the type of cable utilized
to form the network.
 The entire tree topology would fail if the central trunk fails as it forms the
backbone of the network.

The tree topology is comparatively more complex than the bus and star
topologies. If it gets bigger, it would be difficult to configure and manage it.
 It is expensive as more hubs and cables are required to install the network.
13.8.6
Mesh Topology
The mesh topology incorporates a unique network design in which each computer on
the network connects to every other, creating a point-to-point connection between every
device on the network. The purpose of the mesh design is to provide a high level of
redundancy. If one network cable fails, the data always has an alternative path to get to
its destination An example of a Mesh Network is the Mobile Adhoc Network or
MANet. Mesh topology can also be called as fully connected network as each node is
connected to other node via cables in the network.
Mesh Topology
Advantages of Mesh topology
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As it has multiple routes between the source and the destination, if one route
fails, there would be a number of other routes through which data transfer can
take place.
Traffic problem is minimized in this topology.
Troubleshooting is easier compared to other networks like star and ring.
Heavy load of data transfer has little impact on the performance of this
topology.

This network can be easily expanded without affecting the existing users.
Disadvantages of Mesh topology


It is expensive as it requires more cable than other topologies.
Installation is difficult and complicated.
13.8.7
Hybrid Topology
A hybrid topology, as the name suggests, is an interconnection of two or more
networks. The component networks may be ring, star, tree, mesh or any other,
depending upon the requirement of a firm or institution. For example, in an institution,
if there is a ring topology in one department, bus topology in the next department, star
topology in another department and so on, all the departments can connect to each
other through a bus topology that connects the ring, bus and star topologies of each
department to each other. Such a topology that consists of more than one type of
individual
topologies
is
known
as
hybrid
topology.
Hybrid topology
Advantages of hybrid topology
 Hybrid topologies are reliable and have increased fault tolerance than other
topologies.
 A hybrid topology can efficiently diagnose and isolate faults.
 Hybrid topologies are flexible and are designed to suit a variety of network
environments and needs.

A hybrid topology is able to tap into the strengths of other topologies and ignore
their weaknesses. This results in a complex network that is more efficient and
effective than individual topologies
Disadvantages of hybrid topology

Comparatively expensive than other topologies.
Freeware
Software which is distributed free by the author. freeware is proprietary software made
available free of charge. It is the programming that is offered at no cost and is a common class of
small applications available for downloading and use in most operating systems. Although it is
available for free, the author retains the copyright, which means that it cannot be altered
or sold.
Free software is distinct from freeware; Free software may be packaged and distributed for a fee; the
"free" refers to the ability to reuse it, modified or unmodified, as part of another software package. As
part of the ability to modify, users of free software may also have access to and study the source code.
The term 'free' does not mean free of charge. It refers to a user's freedom to run, copy,
distribute, study, change and improve the software without the payment of a royalty or
obtaining express permission. Everyone is free to sell copies of free software, to use it
commercially, and to charge for distribution and modifications. Because anyone who
has a copy may distribute the software at no cost, the software generally is available at
no cost. Free software business models are usually based on adding value such as
support, training, customization, integration, or certification like open source softwares
are free softwares.
13.13.4
Shareware
Software distributed freely, but with certain conditions applying to it. It is distributed
free on a trial basis with the understanding that the user may need or want to pay for it
later. Either the software is released on a trial basis only, and must be registered after a
certain period of time, or in other cases no support can be offered with the software
without registering it. In some cases direct payment to the author is required. Some
software developers offer a shareware version of their program with a built-in
expiration date (after 30 days, the user can no longer get access to the program). Other
shareware (sometimes called liteware) is offered with certain capabilities disabled as an
enticement to buy the complete version of the program.
13.13.5
FLOSS/FOSS
FLOSS is common and combined term of Free/Libre/Open Source Software.
Actually this term for free software and open source where free means it was cost free software Libre
means liberty : to make changes Open source means code or patch files are available openly to fix bugs,
and for further development.
13.13.6
GNU
GNU is a computer operating system composed entirely of free software. Its name is a
recursive acronym for GNU's Not Unix, which was chosen because its design is Unix
like, but differs from Unix by being free software and by not containing any Unix
code.GNU was founded by Richard Stallman and was the original focus of the Free
Software Foundation
GNU Public License (GPL)
Most new open source software around these days uses this license, as does Moodle. In
a nutshell, the GPL says:





Anyone can download, use, modify and distribute this software
All modified versions must ALSO be under the GPL license
All copyright notices must be maintained, and all modifications must be clearly
marked
All distributions must include the full source code
There is no warranty on the software
13.13.7
FSF
The Free Software Foundation (FSF)was established in 1985 to promote the
development of free software with full rights to use, study, copy, modify, and
redistribute computer programs. particularly the GNU operating system, used widely
in its GNU/Linux variant. Its a non profit, non political and international organization
provides standards for developing free softwares.
13.13.8
OSI
Open Source Initiative (OSI) is a non-profit corporation dedicated to managing and
promoting the Open Source Definition for the good of the community, specifically
through the OSI Certified Open Source Software certification mark and program.
The basic idea behind open source is to read, redistribute, and modify the source code
for a piece of software, the software evolves. People improve it, people adapt it, people
fix bugs. We in the open source community have learned that this rapid evolutionary
process produces better software than the traditional closed model, in which only a
very few programmers can see the source and everybody else must blindly use an
opaque block of bits.
13.13.9
Linux :
Examples of Open source software
Like Windows and Unix ,Linux is also an operating system developed Linus Torvalds but this operating
system was freely distributed as Open Source i.e code is freely available to read ,edit and fix bugs.
Apart from the fact that it's freely distributed, Linux's functionality, adaptability and robustness, has
made it the main alternative for proprietary Unix and Microsoft operating systems. IBM, HewlettPackard atre the top companies which has embraced Linux and support its ongoing development. It was
primarily adapted as a server platform.
Mozilla
An open-source XML/HTML browser have with dynamic image and table resizing, quick insert and
delete of table cells, improved CSS support.
It is a free web browser descended from the Mozilla Application Suite, managed by the Mozilla
Corporation. It is the second-most popular browser currently worldwide, after Internet Explorer. Firefox
includes tabbed browsing, a spell checker, incremental find, live bookmarking, a download manager, and
an integrated search system that uses the user's desired search engine. Functions can be added through
around 2,000 add-ons created by third-party developers, the most popular of which include NoScript
(script blocker), Stumble Upon (website discovery), Tab Mix Plus (adds many customizable options to
tabs), FoxyTunes (controls music players), Adblock Plus (ad blocker), DownThemAll! (download
functions) and Web Developer (web tools).
Apache HTTP Server
The Apache HTTP Server is to develop and maintain an open-source web server for
modern operating systems including UNIX and Windows NT. The goal of this project is
to provide a secure, efficient and extensible server that provides HTTP services in sync
with the current HTTP standards.Apache has been the most popular web server on the
Internet since April 1996.
Uses of apache are:
Serves both static content and dynamic Web pages on the World Wide Web. Apache
provides environment to run web applications like java based and XML
MYSQL
MySQL is the world's most popular open source database software. It is a structured query language like
SQL used for managing database systems.Many of the world's largest and fastest-growing organizations
use MySQL to save time and money powering their high-volume Web sites, business-critical systems and
packaged software -- including industry leaders such as Yahoo!, Alcatel-Lucent, Google, Nokia.
POSTGRES
PostgreSQL is an object-relational database management system (ORDBMS). It is released under as a free
software. And like other open-source programs, PostgreSQL is not controlled by any single company,
but relies on a global community of developers and companies to develop it.
PANGO
Pango is a free and open source computing library for rendering internationalized texts in high quality.
Pango has been integrated into most Linux distributions. It most notably provides the rendering for text
in the Mozilla Firefox web browser Different font backends can be used, allowing cross-platform support.
PHP:
Hypertext Pre Processor (PHP) is a server side technology introduced to design
dynamic and interactive web pages. PHP is the widely-used, free, and efficient
alternative to competitors such as Microsoft's ASP. PHP is perfectly suited for Web
development and can be embedded directly into the HTML code. The PHP syntax is
very similar to Perl and C. PHP is often used together with Apache (web server) on
various operating systems. It is based on open source technology under PHP license to
develop graphic and web applications.
It was written as a set of Common Gateway Interface (CGI) binaries in the C
programming language by the Danish/Greenlandic programmer Rasmus Lerdorf in
1994, to replace a small set of Perl scripts he had been using to maintain his personal
homepage.
PYTHON
Python is a multi-paradigm programming language (functional, object oriented and
imperative) which has a fully dynamic type system and uses automatic memory
management; it is thus similar to Perl, Ruby, Scheme, and Tcl.
The language has an open, community-based development model managed by the nonprofit Python Software Foundation.
TOMCAT
Tomcat is an application server developed at the Apache Software Foundation (ASF).
To run java applications on web server It has its own internal HTTP server and
implements the Java Servlet and the JavaServer Pages (JSP) specifications from Sun
Microsystems, providing an environment for Java code to run in cooperation with a
web server.
OPENOFFICE
The OpenOffice.org project aims "To create, as a community, the leading international office
suite that will run on all major platforms and provide access to all functionality and data
through open-component based APIs and an XML-based file format like Microsoft Office”.
It is free and open source office suit, including
Writer : A word Processor
Calc : Spread sheet software similar to Micrpsofyt Excel
Quick Review:
Definitions:
Network:
Internet
A network is an interconnected collection of autonomous
computers
It is the network of networks that transmit data by packet
switching using a standardised Internet Protocol (IP) and many
other protocols.
Interspace
Interspace is the networked virtual reality system on the Internet.
Bandwidth:
The range of transmission frequencies that can be carried on a
communication line is referred to as the bandwidth of the line
device, which converts digital signal into analog, and the
reverse, is known as modem.
Modem:
Modulation:
The technique by which a digital signal is converted to
analogform is known as modulation.
Topology
refers to the layout or design of the connected devices
Protocol
A protocol is a set of rules that governs the communications
between computers on a network.
is a protocol for remote computing on the Internet. It allows a
computer to act as a remote terminal on another machine,
anywhere on the Internet
Wireless local loop (WLL) technology simply means that the
subscriber is connected to the nearest exchange through a radio
link instead of through these copper wires.
is the text communication service component of phone, web or
mobile communication systems, using standardized
communications protocols that allow the exchange of short text
messages between fixed line or mobile phone devices
Telnet
Wireless local
loop
Short Message
Service (SMS)
Voice Mail :
The electronic transmission of voice messages over the Internet. The
messages are stored on a computer until the recipient accesses and
listens to them
Email,
also sometimes written as e-mail, is simply the shortened form of
electronic mail, a protocol for receiving, sending, and storing
electronic messages
chatting:
On line talk in the form of text is known is chatting.
video
conferencing:
A videoconferencing or video conference (also known as a
videoteleconference) is a set of interactive telecommunication technologies
which allow two or more locations to interact via two-way video and audio
transmissions simultaneously
Viruses :
Cookies
Firewall
Cyber Law
Computer programs written by devious programmers and
designed to replicate themselves and infect computers when
triggered by a specific event.
are small bits of information that get stored on your hard drive
(persistent cookies) or in memory (non-persistent cookies) of
your computer. They are placed on your computer by the
websites you are visiting.
stands between the company’s network and a public network,
effectively shielding your computers from malicious hacker activity,
and controlling the flow of data
is the law governing cyber space.It is a very wide term and includes
computers, networks, software, data storage devices (such as hard
disks, USB disks etc), the Internet, websites, emails and even
electronic devices such as cell phones, ATM machines etc.
World Wide Web
It is a repository of information containing a set of programs ,
standards and protocols that allows the multimedia and hypertext files
to be created , displayed and linked on the internet.
W3C
The organization responsible for managing standards for the WWW.
Browser
A browser is an application which provides a window to the
Web. For example : Internet explorer ,Mozilla Firefox.
Web Page
A document formatted for distribution over the web. Most often a web
document is formatted in a markup language like HTML or XML.
Web Document
A document formatted for distribution over the web. Most often a web
document is formatted in a markup language like HTML or XML.
Website
A collection of related web pages belonging to a company or an
individual.
URL
(Uniform A URL refers to an address in the special format on the internet.
Resource Locator)
It is a standard way to address web documents (pages) on the Internet
(like: http://www.microsoft.com/). URL are of two types: absolute
URL ,relative URL
Web Host
A web server that "hosts" web services like providing web site space to
companies or individuals.
Web Hosting
The action of providing web host services.
Domain name
A domain name is a unique name for a web site, like ntchosting.com
.Domain names must be registered
An Internet
Protocol address
(IP address)
is a numerical label that is assigned to any device participating
in a computer network that uses the Internet Protocol for
communication between its nodes
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In 1969 by the development of first network called ARPANET , led to the development of
internet .
ARPANET ( Advanced Research Projects Agency NETwork) was the project for
connecting computers at different Universities and U.S. defense.
network architecture: peer to peer network ,client server networking.
peer to peer networks : All computers are of equal importance. Software and data are
stored on each computer.
client/server network: Software and data are held on a file server and may be used by
other computers on the network. Security is controlled centrally.
Local-Area Networks (LANs)
The computers are geographically close together (that is, in the same building).
Wide-Area Networks (WANs)
The computers are farther apart and are connected by telephone lines or radio waves.
MAN - Metropolitan Area Network : It covers large span of physical area than LAN
but smaller than WAN, such as a city.
Personal area network (PAN) is a computer network designed for communication
between computer devices(including telephones and personal digital assistants close to
one person)
The Internet, or simply the Net, is the information superhighway.
The end devices that wish to communicate with each other are called stations.
The switching devices are called nodes
there are three types of switching: Circuit Switching ,Packet Switching and Message
Switching


In circuit switching, a circuit is first established and then used to carry all data between
devices. example: telephone system
In packet switching no fixed path is created between devices that communicate; it is
broken into packets, each of which may take a separate path from sender to recipient.
example : connecting internet using dial up modem.

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message switching: In this technique, the source computer sends data or the message to
the switching office first, which stores the data in its buffer.example : email
Frequency is measured in hertz(Hz).
1 MHz = 1million Hz
Baud: It describes the rate of change of the signal on the line i.e.how many times (per
second) the signal changes its pattern.
Data Transfer rate : A data transfer rate is the amount of digital data that is moved
from one place to another in a given time usually in seconds. In general, the greater the
bandwidth of a given path ,higher the transfer rate.
Bit rate : A data transfer rate expressed in bits per second .
Kbps= 1000 bits per second
Mbps=1000 kbps=1,000,000bps
Gbps=1000 mbps
Tbps=1000gbps
Twisted pair cable : two type shielded and unshielded Twisted Pair(UTP)
o Advantages: Reasonable cost ,High Speed ,Easy to add additional network
devices ,Supports large number of network devices, Easy to install, because of
physical flexibility, low weight & easy connectivity.
o Disadvantages of twisted pair: Signals loose energy due to attenuation, so
repeaters are required, Bandwidth is low, High attenuation (signal loss) limits
individual runs to 100 meters
Cat-5Short for Category 5, network cabling that consists of four twisted pairs of copper
wire terminated by RJ45 connectors. Cat-5 cabling supports frequencies up to 100 MHz
and speeds up to 1000 Mbps. It can be used for ATM, token ring, 1000Base-T, 100BaseT, and 10Base-T networking. Computers hooked up to LAN s are connected using Cat-5
cables, so if you're on a LAN, most likely the cable running out of the back of your PC is
Category 5.
Coaxial cable : Coaxial cable, in its simplest form, is a single wire wrapped in a foam
insulation,surrounded by a braided metal shield, then covered in a plastic jacket
o advantages: greater bandwidth ,greater channel capacity and low error rates.
o disadvantage: Problems with the deployment architecture, Bidirectional
upgrade required, Great noise, High installation costs, Susceptible to
damage from lightning strikes.
Infrared ,radiowave ,microwave and satellite are wireless technology for
communication.
NIC known as network interface card : network device required to access the
network .
Hub: a network device to connect more than two computer on network .it is
preferred for small network where number of nodes are less than 30.

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Switch: Basically a multiport bridge that segments a network into many smaller
collision domains while maintaining the broadcast characteristics. Greatly
improves the performance of LANs
A Router is responsible for connecting two physical and logically different
networks.
A repeater connects two segments of your network cable.
A bridge is a product that connects a local area network (LAN) to another local
area network that uses the same protocol (for example, Ethernet or Token Ring).
Topology can be classified into two :
o 1-D (bus)
o 2-D (tree, stars, rings, mesh, etc.)
Protocol can be classified into two groups : network and communication
protocol.
Network protocol : Ethernet ,FDDI,ATM, Local talk ,token ring.
Communication protocols : HTTP,FTP,TCP/IP,SMTP,SLIP,PPP,POP3
SMTP and POP3 are email protocols.
Wireless and mobile communication technology:
o FDMA
o GSM
o TDMA
o CDMA
o 3G
o 4G
EDGE and Wimax are 3G technologies .
 CDMA(Code Division Multiple Access) :
It is a digital cellular technology which uses spread spectrum techniques means the data is sent in
small pieces over a number of discrete frequencies available for use in the specified range .All the
users will transmit in the same wide spectrum. Each user‘s signal is spread over the entire bandwidth
by a unique spreading code . At the receiver’s end same unique code is used to recover the signal.
CDMA has been used in many military applications, such as:



Anti-jamming (because of the spread signal, it is difficult to jam or interfere with a CDMA signal).
Ranging (measuring the distance of the transmission to know when it will be received).
Secure communications (the spread spectrum signal is very hard to detect).


Time Division Multiplexing:TDMA works by dividing a radio frequency into time slots and
then allocating slots to multiple calls . In this way ,a single frequency an support multiple,
simultaneous data channels
Frequency Division Multiple Access (FDMA): allocates users with different carrier frequencies
of the radio spectrum.The radio spectrum is available to the users where communications


signals are pass through that spectrum. Multiple access enables allows more than one
communications signal to pass within a particular band
Enhanced Data rates for GSM Evolution (EDGE) or Enhanced GPRS(EGPRS),
It is an Advanced technology over GSM which is widely used in digital mobile phone technology
which allows increased data transmission rate .This technology was developed in North America
and used extensively in packet switched applications such as Internet Connection, VDO services
,multimedia services .


Protocols for chat and video conferencing : VoIP.



Network security : protection from threats to network.


In 1981 - First virus Elk Cloner was transmitted by floppy disk.

Voice over Internet Protocol (VoIP), is a technology that allows you to make voice calls using a
broadband Internet connection instead of a regular (or analog) phone line.
Threats to network security are viruses ,worms ,Trojan horse
In a computer, a worm is a self-replicating virus that does not alter files but
resides in active memory and duplicates itself. Worms use parts of an operating
system that are automatic and usually invisible to the user.
Spam is flooding the Internet with many copies of the same message, in an
attempt to force the message on people who would not otherwise choose to
receive it.
There are various ways to protect from network threats some are :
o Authentication Definition
o Authorization Definition
o Identity Management
o Firewall
o Identification methods
o Antiviruses

The Information Technology Act 2000 (ITA-2000)(IT ACT) is an Act of the Indian Parliament for
cyber related issues.

hackers are intelligent people who breaks into a system for gaining knowledge
,freely share what they have discovered, and never, ever intentionally damage data.
crackers are “ evil hackers “who breaks into or otherwise violates the system integrity of

remote machines, with malicious intent.



HTML :Hypertext markup language for designing web sites.
XML( EXtensible Markup Language) is a standard, simple, self-describing way of
encoding both text and data so that content can be processed with relatively
little human intervention and exchanged across diverse hardware, operating
systems, and applications
server side scripting languages:The code which is executed at server end is
called server side script and computer languages used to write this script are
called server side scripting languages Examples of server side scripting
languages are CGI, ASP and PHP,JSP

Client side scripting:The response or output of web server is send to requesting
client. This response consists of HTML and some other script. The HTML is
rendered by browser. Browser also executes the script received from server. This
script or small program embedded in HTML is called client side script and
languages used to write this script are client side scripting languages .Forex:
JavaScript and VB Script.

The term ‘Web 2.0’ refers to the idea of the “New Internet”, or the second wave of the World
Wide Web. Web 2.0 is not a specific application or technology, but explains two paradigm shifts
within Information Technology, ‘user-generated content’ and ‘thin client computing’.

Major difference between bridge ,router and gateway is bridges are used to connect same
network and having same network protocols while router is used to connect same LAN network
with different set of protocols while gateway is used to connect different networks.
 To connect very high range of network use satellite communication where range of signals is
very high.
 Thick Coaxial cables support up to 500ms for greater than that range use optical fibers for better
.data transmission.
 Switch manages the data required for larger network approximately 50 and above .

High level connectivity could be provided by radio transmission using satellite channels .
 Wireless networking known as WLL speed comes in 54mbps,108mbps.
 HTML is used for designing web pages has predefined tags to be used while in XML you can
define your own tags.
 A newsgroup is online community bulletin board where users can post messages , respond to
posted messages or just read them.
 ARCHIE is a software tool that help you search for the files stored on FTP server.
 Cyber law means 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.
 Important Definitions :
1. DHTML -- (Dynamic Hypertext Markup Language) : DHTML refers to web pages that use a
combination of HTML, JavaScript, and CSS to create features such as letting the user drag items
around on the web page, some simple kinds of animation, and many more.
2. Extranet : An intranet that is accessible to computers that are not physically part of a company’s'
own private network, but that is not accessible to the general public, for example to allow
vendors and business partners to access a company web site. Often an intranet will make use of
a Virtual Private Network. (VPN.)
3. Fire Wall : A combination of hardware and software that separates a Network into two or more
parts for security purposes.
4. FTP -- (File Transfer Protocol) : A very common method of moving files
between two Internet sites. FTP is a way to login to another Internet site for the purposes of retrieving
and/or sending files. There are many Internet sites that have established publicly accessible
repositories of material that can be obtained using FTP, by logging in using the account name
"anonymous", thus these sites are called "anonymous ftp servers".
5. Gateway : The technical meaning is a hardware or software set-up that
translates between two dissimilar protocols, for example America Online has a gateway that
translates between its internal, proprietary e-mail format and Internet e-mail format. Another,
sloppier meaning of gateway is to describe any mechanism for providing access to another system,
e.g. AOL might be called a gateway to the Internet.
6. Email -- (Electronic Mail) : Messages, usually text, sent from one person to
another via computer. E-mail can also be sent automatically to a large number of addresses.
7. GIF -- (Graphic Interchange Format) : A common format for image files,
especially suitable for images containing large areas of the same color. GIF
format files of simple images are often smaller than the same file would be if stored in JPEG format,
but GIF format does not store photographic images as well as JPEG.
8. Gopher : Invented at the University of Minnesota in 1993 just before the Web, gopher was a
widely successful method of making menus of material available over the Internet. Gopher was
designed to be much easier to use than FTP, while still using a text-only interface.
9. Hypertext : Generally, any text that contains links to other documents – words or phrases in the
document that can be chosen by a reader and which cause another document to be retrieved and
displayed.
10. Internet (Upper case I) : The vast collection of inter-connected networks that are connected using
the TCP/IP protocols and that evolved from the ARPANET of the late 60's and early 70's. The
Internet connects tens of thousands of independent networks into a vast global internet and is
probably the largest Wide Area Network in the world.
11. Intranet : A private network inside a company or organization that uses the same kinds of
software that you would find on the public Internet, but that is only for internal use. Compare
with extranet.
12. IP Number -- (Internet Protocol Number) :Sometimes called a dotted quad.
A unique number consisting of 4 parts separated by dots, e.g. 165.113.245.2. Every machine that is on
the Internet has a unique IP number - if a machine does not have an IP number, it is not really on the
Internet. Many machines (especially servers) also have one or more Domain Names that are easier for
people to remember.
13. ISDN -- (Integrated Services Digital Network) : Basically a way to move more
data over existing regular phone lines. ISDN is available to much of the USA and in most markets it is
priced very comparably to standard analog phone circuits. It can provide speeds of roughly 128,000
bits-per-second over regular phone lines. In practice, most people will be limited to 56,000or 64,000
bits-per second. Unlike DSL, ISDN can be used to connect to many different locations, one at a time,
just like a regular telephone call, as long the other location also has ISDN.
14. ISP -- (Internet Service Provider) : An institution that provides access to the Internet in some
form, usually for money.
15. JPEG -- (Joint Photographic Experts Group) : JPEG is most commonly
mentioned as a format for image files. JPEG format is preferred to the GIF format for photographic
images as opposed to line art or simple logo art.
16. Leased Line : Refers to line such as a telephone line or fiber-optic cable that is rented for
exclusive 24-hour, 7-days-a-week use from your location to another location. The highest speed
data connections require a leased line.
17. Modem -- (Modulator, Demodulator) : A device that connects a computer to a phone line. A
telephone for a computer. A modem allows a computer to talk to other computers through the
phone system by converting digital signals to analog and vice versa. Basically, modems do for
computers , what a telephone does for humans.
Modem are of two types:
Internal modem : are the modem that are fixed within the system.
External modem : are the modems that are connected externally to a computer as other peripheral
devices are connected.
18. Mosaic : The first WWW browser that was available for the Macintosh,
Windows, and UNIX all with the same interface. Mosaic really started the
popularity of the Web. The source-code to Mosaic was licensed by several
companies and used to create many other web browsers.
19. PDF -- (Portable Document Format) : A file format designed to enable
printing and viewing of documents with all their formatting (typefaces, images, layout, etc.)
appearing the same regardless of what operating system is used, so a PDF document should look the
same on Windows, Macintosh, Linux, OS/ 2, etc. The PDF format is based on the widely used
Postscript document description language. Both PDF and Postscript were developed by the Adobe
Corporation.
20. OSS : Open source software.
21. OSI: Open Source Initiative (OSI) is a non-profit corporation dedicated to managing and
promoting the Open Source Definition.
22. Berkeley Source Distribution (BSD):one of the license for open source software
23. Apache – open source web server software .
24. Mozilla is open source web browser.
25. Linux is an open source operating system.
26. PHP is an open source web scripting language
27. Tomcat is the web server supports java applications to run.
28. Python is an open source programming language like Perl etc.
29. MySQL is an open source database language.
 FAMILY OF PROTOCOLS
30. SMTP - Simple Mail Transfer Protocol : The SMTP protocol is used for
the transmission of e-mails.
31. MIME - Multi-purpose Internet Mail Extensions : The MIME protocol
lets SMTP transmit multimedia files including voice, audio, and binary data across TCP/IP networks.
32. IMAP - Internet Message Access Protocol : The IMAP protocol is used for
storing and retrieving e-mails.
33. POP - Post Office Protocol : The POP protocol is used for downloading emails from an e-mail
server to a personal computer.
34. FTP - File Transfer Protocol : The FTP protocol takes care of the transmission of files between
computers.
35. NTP - Network Time Protocol : The NTP protocol is used for synchronizing the time (the clock)
between computers.
36. SNMP - Simple Network Management Protocol : The SNMP protocol is
used for the administration of computer networks.
37. ICMP - Internet Control Message Protocol : The ICMP protocol takes care of error handling in
the network.
38. ARP - Address Resolution Protocol : The ARP protocol is used by IP to find the hardware
address of a computer network card based on the IP address.
39. RARP - Reverse Address Resolution Protocol : The RARP protocol is used by IP to find the IP
address based on the hardware address of a computer network card.
40. PPTP - Point to Point Tunneling Protocol : The PPTP protocol is used for
setting up a connection (tunnel) between private networks.
41. SMTP - Simple Mail Transfer Protocol : The SMTP protocol is used for
the transmission of e-mails. SMTP takes care of sending your email to another computer. Normally
your email is sent to an email server (SMTP server), and then to another server or servers, and finally
to its destination. SMTP can only transmit pure text.
42. POP - Post Office Protocol : The POP protocol is used by email programs
(like Microsoft Outlook) to retrieve emails from an email server. If your email program uses POP, all
your emails are downloaded to your email program (also called email client), each time it connects to
your email server.
43. IMAP - Internet Message Access Protocol “ The IMAP protocol is used by email programs (like
Microsoft Outlook) just like the POP protocol. The main difference between the IMAP protocol
and the POP protocol is that the IMAP protocol will not automatically download all your emails
each time your email program connects to your email server.
Short Questions
1. What is networking?
Ans Networking is the term used to describe connectivity between the systems with
or without Cables or satellites.
2. What is website?
Ans It is the collection of web pages used to link text or images with each other. Ex
www.yahoo.com
3. Define the term topology.
Ans It is the framework or arrangement of systems on network ex: ring ,star, bus etc
4. What are the two types of topology.
Ans Star Topology
Bus Topology
5. What is LAN?
Ans LAN stands for Local Area Network. It is the connectivity of systems within
the local organization covers around 100 ms area
6. What do you understand by protocol.
Ans A set of rules or instructions govern communication on computer network are
called protocols.
7. EDGE stands for… …………
Ans Enhanced Data rates for GSM Evolution
8. Which protocol is used for sending and receiving emails respectively?
Ans SMTP used for sending emails and POP for receiving emails.
9. How TCP/IP works.
Ans TCP/IP(Transmission Control Protocol /Internet Protocol)
A collection of Internet communication protocols between two computers. The
TCP protocol is responsible for an error free connection between two computers,
while the IP protocol is responsible for the data packets sent over the network.
TCP splits message into fixed size datagram which are then tagged with
destination address and sent to receiver where the datagram are merged to form
proper message.
IP is the protocol controlling addressing on the network . As and when any
computer gets connected to the network, it must owe a unique address with
which it will be identified by other systems. IP protocol assigns address to the
different system on the network.
10. FDDI is an example of ________
Ans token ring network
11. Token ring is based on ___________
Ans ethernet
12. MODEM is used for _____________ and _________________
Ans modulation
demodulation
13. What is the significance of HTTP and FTP .
Ans HTTP (Hyper Text Markup Protocol ) : This protocol is responsible for accessing
hypertext documents on world wide web. Set of rules governing exchange of
hypertext between two computers is commonly known as HTTP. It consists of 2
distinct items a set of requests from browsers to servers
 a set of responses from server to browsers
FTP (File transfer protocol ) :It defines a method for transferring large files
from one computer to another over a network. Set of rules, which enables files
to be uploaded or downloaded on a network is known as FTP. It is very effective
way to get a geographically dispersed group to co-ordinate on a project and
share information on the internet. It serves as client server process.
Downloading : refers to transfer of files from FTP server to your computer.
Uploading : refers to transfer of files from your computer to FTP servers. Only
authorized users can upload a file .Most common use of FTP is to download and
upload a file
14. What is XML?.
Ans
XML (eXtensible Markup Language) :
It is a meta language for describing the markup languages A simplified version
of SGML especially designed for web documents, developed by the W3C.. There
is no predefined tag set. It will be defined by either the application that process
them or by style sheets.
15. What do you understand by the term e-commerce.
Ans Ecommerce stands for electronic commerce i.e buying and selling of products or
services over electronic systems such as the Internet and other computer
networks.
16. Explain the types of networks.
Ans Types of networks:


LAN-Local area network
 Privately owned networks
 Used to connect PC’s and workstation within a building or computers in
an area upto 100mts of range.
 Speed of data transmission is not very high
MAN-Metropolitan Area Network

Bigger version of LAN

May be private or public

Covers a group of nearby offices or city
WAN-Wide area network

Spans a large geographical area like countries

Public Network

Speed very high
17. What is search engine .Name any four search engines.
Ans A search engine is program or an information retrieval system designed to help
find information stored on a computer system. Search engines help to minimize
the time required to find information and the amount of information on any
topic .
Ex: www. google.com, www.yahoo.com, www.khoj.com, www.altavista.com
18. What is web browser .Name any two commonly used web browsers..
Ans A web browser is a program which is used to visit web pages . The two most
well known are Netscape Navigator and Microsoft Internet Explorer which are
used by vast majority .Some other browsers are MOSAIC , LYNX , OPERA etc.
19. What is the syntax of URL?.
Ans A Uniform Resource Locator refers to an address in the special format on the
internet .It is a standard way to address web documents (pages) on the Internet
(like: http://www.microsoft.com/)
20. What is bandwidth and baud rate.
Ans The range of transmission frequencies that can be carried on a communication
line is referred to as the bandwidth of the line .In digital systems bandwidth is
data speed in bits per second (bps).
Baud rate:
It describes the rate of change of the signal on the line i.e.how many times (per
second) the signal changes its pattern. The baud rate is the measure of the
modulation rate ,the number of discrete signaling events per second. In low
speed modem the baud is same as bit rate.
21. Explain the following terms:
a. Email
b. Chatting
c. Videoconferencing
d. Domain Name System
e. GSM
f. Telnet
g. Veronica
h. Usenet
i. WAIS
j. Mosaic
Ans
a. Email : Electronic mail is the way of sending and receiving messages
electronically.
Major advantage is easy record maintenance, Low
cost and fast delivery.
b. Chatting: On line talk in the form of text is known is chatting. In chatting as
you type a message on the screen which is immediately received by the
recipient then the recipient can type a message in response to your message
which is received by you instantly.
Sites which provide this facility are http:/ chat .yahoo.com , chat.123india.com
, chat.sify.com
c. Videoconferencing:
is a set of interactive telecommunication technology
which allow two or more locations to interact via two-way video and audio
transmissions simultaneously.
d. Domain Name System : A domain name is a unique name for a web site, like
yahoo.com .Domain names must be registered. When domain names are
registered they are added to a large domain name register, and information
about your site - including your internet IP address - is stored on a DNS server.
e. DNS stands for Domain Name System. A DNS server is responsible for
informing all other computers on the Internet about your domain name and
your site address
f. GSM(Global system for Mobile):
It is one of the leading digital cellular system for mobile communication .The
digital nature of GSM allows data, both synchronous and synchronous data, to
be transported as a bearer service to or from an ISDN terminal. The data rates
supported by GSM are 300 bps, 600 bps, 1200 bps, 2400 bps, and 9600 bps.
The most basic teleservice supported by GSM is telephony. A unique feature of
GSM compared to older analog systems is the Short Message Service (SMS).
Supplementary services are provided on top of teleservices or bearer services,
and include features such as international roaming, caller identification, call
forwarding, call waiting, multiparty conversations, and barring of outgoing
(international) calls, among others.
g. Telnet : It is an internet facility that supports remote login.
This facility allows users to access files and execute programs on a remote
computer without being physically present at the actual site of working.
h. Veronica: ‘Veronica’ actually stands for “Very Easy Rodent-Oriented
Netwide Index to Computerized Archives.” It’s a program that allows you to
search the files of the internet’s Gopher servers using keywords. It is a search
engine system for the Gopher protocol. After entering a particular keyword for
searching, Veronica displays a list of gopher menus and articles containing the
keyword you searched for. The more recent versions of Veronica can also
search certain Web pages, newsgroups, and FTP sites.
i. Usenet
:
It is the public bulletin board of the internet and used as a
means to share news and other information among users . It is many to many
conversation.
j.
WAIS
: Wide area information Network ) : is the facility on the
internet that can search for a given item in the database which may be on the
different sites on the internet . Searching can be possible by specifying the
search string or a topic.
k. MOSAIC : It is a graphical WWW browser created by (NCSA) National center
for super Computing applications. It can display hyper text documents that
include digital video , audio , graphic images and text in a variety of formats.
22. Expand the following terms:
a. TCP/IP
b. HTTP
c. FTP
e. DNS
f. IP address g. SMTP
i. IMAP
j. SLIP
k.WLL
m. TDMA
n. FDMA
o. XML
q. NFS
r. CSMA/CD s. NNTP
u. PSTN
v. ISDN
w. W3C
y. MODEM
Ans
a) TCP/IP
b) HTTP
c) FTP
d) URL
e) DNS
f) IP address
g) SMTP
h) POP
i) IMAP
j) SLIP
d. URL
h. POP
l.CDMA
p.WDM
t. GSM
x. WLL
: Transmission Control Protocol/Internet Protocol
: Hyper Text Transfer Protocol
: File Transfer Protocol
: Uniform Resource Locator
: Domain Name System
: Internet Protocol address.
: Simple Mail Transfer Protocol.
: Post Office Protocol.
: Internet Message Access Protocol.
: Serial Line Internet Protocol (SLIP)
k) WLL
l) CDMA
m) TDMA
n) FDMA
o) XML
p) WDM
q) NFS
r) CSMA/CD
s)
t)
u)
v)
w)
x)
y)
NNTP
GSM
PSTN
ISDN
W3C
WLL
MODEM
: Wireless Local Loop
: Code division multiple access (CDMA)
: Time division multiple access (TDMA)
: FDMA (frequency division multiple access)
: Extensible Markup Language (XML)
: wavelength-division multiplexing (WDM)
: Network File System (NFS)
: Carrier Sense Multiple Access / Collision
Detection
: Network News Transfer Protocol
: Global system for Mobile.
: Public Switched Telephone Network
: Integrated Services Digital Network
: World wide web Consortium
: Wireless in Local Loop
: Modulation Demodulation
23. What is web hosting?
Ans
Web hosting means storing your web site on a public server. It normally includes
email services and often includes domain name registration.
24. What is WAN?
Ans WAN-Wide area network

Spans a large geographical area covering countries

Public Network

Speed very high
25. What is the significant of ARPANET in the network?
Ans ARPANET ( Advance Research Projects Agency NETwork) was the project for
connecting computers at different Universities and U.S. defense . Soon the
engineers ,scientists ,students and researchers who were part of this system
began exchanging information and messages on it .ARPANET started with a
handful of computers but it expanded rapidly.
26. What do you understand by peer to peer network
Ans It is also known as non dedicated server . where in small networks work station
that can be doubled up as a server is known as non-dedicated server , since it is
not completely dedicated to the cause of serving. It is a slower and requires more
memory. The small networks using such servers are known as peer to peer
network.
27. What is client server model.
Ans
It is a network in which a workstation (client ) can request information from a
computer that can share resources (server) and fulfills request. The client/server
model provides a convenient way to interconnect programs that are distributed
efficiently across different locations. Computer transactions using the
client/server model are very common.
Advantage : Distribution of work between the client and the server . Server is available to many
clients.
28. Give the usage of the following network devices.
a. Hub
b. Repeater
c. Switch
d. Bridge
e. Router
f. Gateway
Ans
a.
Hub : It is a hardware device used to connect several computers together. Hubs act as junction boxes
,permitting new computers to be connected to the network as easily as plugging a power cord into an
electrical socket, and provide an easy way to connect network cables .It also act as a repeater or
amplifier .Hubs are sometimes also called concentrators, multistation access units or transceivers.
b. Repeater: It is a simple device that amplifies all incoming signals on a
communication channel and transmits them back the regenerated signal. It connects
two segments of your network cable. It retimes and regenerates the signals to proper
amplitudes and sends them to the other segments.
c.
Switches : A switch is a device that is used to divide network into different
subnetworks called LAN segments.It typically provides 10/100Mbps network access speed for each
device connected to it. This is different to a hub which typically operates at 10/100 Mbps but this is
the maximum throughput for all devices attached to it. Hubs cannot cope with the increased
demands of today’s high bandwidth applications, e.g. video conferencing and therefore should be
phased out in favour of switches.
d. Bridge : It is a device that links two networks together which are physically
separate but logically same i.e.the networks that follow the same protocols but
different type of cables.
e. Router :It is a device that works likes a bridge but can handle different types of
protocols . It is also used to balance the traffic on various parts of the network. It
uses logical address whereas the bridge uses physical address .
f. Gateway : It is a system that joins two dissimilar networks together. A network
gateway can be implemented completely in software, completely in hardware, or as
a combination of the two. It expands the functionality by performing data
translation and protocol conversion before transmission. It provides flexibility in
communication.
29. Explain the following topologies diagrammatically for five workgropus connected
with the server:
a. Star topology
b. Ring topology
c. Bus topology
d. Tree topology.
Give two advantages and disadvantages for all of the above topologies.
Ans
a: Star Topology- Most common type of topology used in homes and offices and well
suited for smaller networks. In a star topology, various nodes are connected to a
central connection point called hub which can be computer hub or sometimes switch
alone.
The drop cables are extended in all directions and each device is connected to the hub
via these cables. . It is inherently fault tolerant .
Advantages
If a node goes down, network keeps on working without interruption, only
one computer might get affected and not the entire network.
 Network management is easy because of its simplicity in functionality
 Fault detection is easy , the problems can be easily located logically in a Star
Topology
Disadvantages The Star Topology is fully dependant on the hub and the entire working of
the network depends on the hub or the switch. More cabling is required
 If there are many nodes and the cable is long then the network may slow
down
 The Star Network Topology typically needs more cable to be networked than
the usual Bus topology
Example : Archnet , Ordinary telephone conversation

b. Ring Topology- Also known as daisy chain topology, is large circular cable
and each node is connected to two of its adjacent nodes, thus forming a ring
Advantages
 One node can transmit at a time and collisions do not occur
 Need for repeaters is reduced
Disadvantages
 Each node must handle data transmitted by other nodes.
 If one node fails whole network goes down.
Example : Mitrenet
c. Bus Topology( Multi-drop topology) - It is a method of transmission on networks
that uses a common vehicle (backbone cable) for transmissions and thus it is
categorized as shared communication. Bus topology only one device is allowed to
transmit at a given point of time. A bus structure uses a main trunk
called backbone. The two ends of the backbone are terminated by absorbers, which
absorb the signals passed by all the devices. On the backbone that is a twisted pair
co-axial cable, peripherals and PCs connected with the help of short cables called
drop cables.
Advantages
 Wide range of equipments are attached to such networks.
 A new node can be attached to network without disrupting the network
 Low cabling cost, very easy to set up , Use least amount o cable
Disadvantages




One message can travel at a time
When a message from two nodes comes, a collision can occur. If the data
transfer rate is high then the Bus network does not perform very well because
the data travels in a stream and cannot be overloaded
Reliability is low because a single break in backbone can bring the whole
network down
Fault detection & isolation is difficult
Example : Ethernet
d. Tree Topology:
The shape of network is an inverted tree with central root branching and then
sub-branching till extremes of network. . It is a modification of pure topologies (
combination of star and bus topology ) so is also called hybrid topology. It is best
suited where when the network is widely spread and vastly divided into many
branches & hierarchical flow of data is required.
Advantages
Data communication is very fast as there is a direct link between
nodes.
 A point to point connection is possible with Tree Networks
 Best topology for branched out networks
Disadvantages
 Cabling and setup is quite complex.For big networks it is difficult to
configure and get complicated .
 The Tree Topology network is entirely dependant on the trunk which
is the main backbone of the network. If that has to fail then the entire
network would fail.

30. What is multiplexing.
Ans A term used to refer to a process where multiple analog message signals or
digital data streams are combined into one signal. Ex. Time division mutiplexing,
Frequency Division Multiplexing .
31. Explain FDM and TDM.
Ans FDM(Frequency Division Multiplexing): where multiple baseband signals are
modulated on different frequency carrier waves and added together to create a
composite signal.
In analog transmission, signals are commonly multiplexed using frequencydivision multiplexing (FDM), in which the carrier bandwidth is divided into
subchannels of different frequency widths, each carrying a signal at the same
time in parallel.
TDM (Time division Multiplexing): a type of multiplexing that combines data
streams by assigning each stream a different time slot in a set .It works by
dividing a radio frequency into time slots and then allocating slots to multiple
calls . In this way ,a single frequency an support multiple, simultaneous data
channels.
TDM repeatedly transmits a fixed sequence of time slots over a single
transmission channel. Within T-Carrier systems, such as T-1 and T-3, TDM
combines Pulse Code Modulated (PCM) streams created for each conversation or
data stream.
32. How CDMA is different from all other channel allocation techniques.
A It is a digital cellular technology which uses spread spectrum techniques means
the data is sent in small pieces over a number of discrete frequencies available for
use in the specified range.
33. What do understand by 3G system.
Ans 3G is short for third-generation mobile telephone technology. The services
associated with 3G provide the ability to transfer both voice data (a telephone
call) and non-voice data (such as downloading information, exchanging email,
and instant messaging.
34. What provisions will you take to make your network secure.
A Providing Firewall and antivirus solutions.
35. What is the importance of cookies.
Ans A cookie is a small file that web server can store on your machine . It is the
temporary file that stores information at the client side by the server and thus
reduce the overhead of the server.
36. How firewall acts as security solution.
Ans
It is a combination of specialized hardware and software set up to monitor traffic
between an internal network and an external network (ie the Internet). Its
primary purpose if for security and is designed to keep unauthorized outsiders
from tampering with or accessing information on a networked computer system.
37. Write any two components of openoffice.
Ans
OpenOffice has these components: writer ,calc and draw.
38. How will you explain the concept of WLL.
Ans
WLL is a system that connects subscribers to the public switched telephone network (PSTN) using radio
signals as a substitute for copper for all or part of the connection between the subscriber and the switch.
This includes cordless access systems, proprietary fixed radio access, and fixed cellular systems.
39. What are the following software use for ?
a. PHP
b.
Linux
Ans PHP : Short of Hypertext Preprocessor. It a server side side technology
introduced to design dynamic web pages like ASP,It is based on open source
technology under PHP license to develop graphic and web applications
Linux is an open source operating system.
40. What is token ring? What type of cables are used for token ring?
Ans Token ring is the IEEE 802.5 standard that connects computers
together in a closed ring. Devices on the ring cannot transmit data
until permission is received from the network in the form of an
electronic 'token'.
There are three major physical token ring cabling systems; Shielded
Twisted Pair (STP), Unshielded Twisted Pair (UTP), and optic fiber.
41. What is Ethernet ? To which OSI layer does Ethernet belongs?
Ans
Ethernet is a Local Area Network (LAN) cabling and signaling specification for
baseband networks. Ethernet uses a bus or star topology for connecting different
nodes in a network. Ethernet belongs to both the Physical Layer (Layer 1) and the
Data Link layer (Layer 2) in the OSI architecture.
42. What is a collision ? How is "collision" handled in Ethernet networks?
Ans
At any one instance, in an Ethernet network, only one device can transmit. If two
devices transmit at the same instance, then the signals from both devices will
collide and a "collision" will occur. When a "collision" occurs, the signals will get
distorted and the frame will be lost. Collisions are very common in a Ethernet
network. Ethernet uses the Carrier Sense Multiple Access with Collision
Detection (CSMA/CD) media access control mechanism to detect and recover
from a collision.
43. What is CSMA/CD?
Ans
CSMA/CD is a media access control mechanism used in Ethernet to recover from
frame collision. The following steps are followed to recover from a collision.
Step 1: Before an Ethernet device sends a frame on the Ethernet cable, it listens to
find if another device is already transmitting a frame (Carrier Sense).
Step 2: Once the device finds that other devices are not transmitting any frame, it
starts transmitting the frame. If two devices detect that the Ethernet cable is free
at the same time, then both will start transmitting the frames (Multiple Access).
This will result in collision.
Step 3: The Ethernet devices while transmitting the frames, also listen for the
collision. (Collision Detect).
Step 4: If they detect a collision, both the devices stop sending the frame (back
off).
Step 5: They retry the transmission after a logarithmic time-out period. This
process is repeated till the frame is transmitted successfully, for a maximum of 16
times. The frame is discarded after the 16th retry.
44. What is protocol? How many types of protocols are there?
Ans. When computers communicate each other, there needs to be a common set of
rules and instructions that each computer follows. A specific set of
communication rules is called a protocol.
Some protocol: PPP, HTTP, SLIP, FTP, TCP/IP
45. What is the difference between Networking and Remote Networking?
Ans. The main difference between Networking and Remote Networking, is the
network which we use in offices or other places locally such LAN or INTERNET
and remote networking is one which we use TERMINAL Services to
communicate with the remote users such WAN.
46. What is point-to-point protocol?
Ans. A communication protocol used to connect computer to remote networking
services include Internet Service Providers. In networking, the Point-to-Point
protocol is commonly used to establish a direct connection between two nodes.
Its primary use has been to connect computers using a phone line.
47. How gateway is different from router?
Ans. A gateway operates at the upper levels of the OSI model and translates
information between two completely different network architectures. Routers
allow different networks to communicate with each other. They forward packets
from one network to another based on network layer information. A gateway can
interpret and translate the different protocols that are used on two distinct
networks. Unlike routers that successfully connect networks with protocols that
are similar, a gateway perform an application layer conversion of information
from one protocol stack to another.
48. What is the role of network administrator?
Ans. Basic tasks for which a network administrator may be responsible:
 Setting up and configuring network hardware and software.
 Installing and configuring network media and connections.
 Connecting user nodes and peripherals of all kinds to the network.
 Adding users to and removing users from the network.
 Managing user account.
 Ensuring the security of the network.
 Provide training to the users to utilize the network’s resources.
49. What is the differences between POP3 and IMAP Mail Server?
Ans. IMAP is a standard protocol for accessing e-mail from a local server. A simpler email protocol is Post Office Protocol 3 (POP3), which download mail to the
computer and does not maintain the mail on the server.
IMAP, e-mails are stored on the server, while in POP3, the messages are
transferred to the client’s computer when they are read.
50. Name different layer of the ISO-OSI Model.
Ans. ISO-OSI (International Standard Organization – Open Systems Interconnection)
has seven layers;
 Physical Layer
 Data Link Layer
 Network Layer
 Transport Layer
 Session Layer
 Presentation Layer
 Application Layer
51. What is client server architecture?
Ans. To designated a particular node which is well known and fixed address, to
provide a service to the network as a whole. The node providing the service is known as
the server and the nodes that use that services are called clients of that server. This type
of network is called Client-Server Architecture.
52. What is FDM? Give example.
Ans. FDM-Frequency Division Multiplexing is used in analog transmission. It is often
used in short distance. It is code transparent and any terminal of the same speed can use
the same sub-channel after the sub-channel is established. The best example if FDM is
the way we receive various stations in a radio.
53. What is interspace?
Ans The Interspace is a vision of what the Internet will become, where users crosscorrelate information in multiple ways from multiple sources.
54. Compare twisted pair cable and co-axial cable.
Ans A twisted pair consists of two insulated copper wires, each with its own plastic
insulation, twisted together in a helical form.
Coaxial cable is an electrical cable consisting of a single round conducting wire,
surrounded by an insulating spacer, surrounded by a cylindrical conducting
sheath, and usually surrounded by a final insulating layer.
55. Define the following terms : Share ware , GSM , TCP/IP
Ans Shareware: A method of marketing software where a program is distributed
freely, and users may try it before paying for it.
GSM: Global System for Mobiles, it is the international standard for wireless
technology. GSM allows users to utilize one phone and one number in many
countries throughout the world.
TCP/IP: Transmission Control Protocol/Internet Protocol. A group of protocols
that specify how computers communicate over the Internet.
56. Describe the following in brief:
i) MOSAIC
ii) USENET
iii) WAIS
Ans. i) MOSAIC: is the program for cruising the internet. The National centre wrote
this program for Super Computer application at the university of Illinois. It has a simple
window interface, which creates useful hypertext links that automatically perform some
of the menu bar and button functions.
ii) USENET: is the way to meet people and share information. Usenet newsgroup is a
special group set up by people who want to share common interests ranging from
current topic to cultural heritages.
iii) WAIS: is a WIDE AREA INFORMATION SERVER.
57. What is FLOSS.
Ans FLOSS is common and combined term of Free/Libre/Open Source Software.
Actually this term for free software and open source where
free means it was cost free software. Libre means liberty : to make changes
Open source means code or patch files are available openly to fix bugs, and for
further development.
58. Explain the term GPL.
Ans GNU Public License (GPL)
Most new open source software around these days uses this license, as does
Moodle. In a nutshell, the GPL says:


Anyone can download, use, modify and distribute this software
All modified versions must ALSO be under the GPL license
All copyright notices must be maintained, and all modifications must be clearly
marked
All distributions must include the full source code

There is no warranty on the software


59. What is FSF.
Ans The Free Software Foundation (FSF)was established in 1985 to promote the
development of free software with full rights to use, study, copy, modify, and
redistribute computer programs. particularly the GNU operating system, used
widely in its GNU/Linux variant.Its a non profit, non political and international
organization provides standards for developing free softwares.
60. What is GNU.
Ans GNU is a computer operating system composed entirely of free software. Its
name is a recursive acronym for GNU's Not Unix, which was chosen because its
design is Unix-like, but differs from Unix by being free software and by not
containing any Unix code.GNU was founded by Richard Stallman and was the
original focus of the Free Software Foundation.
61. What is OSI.
Ans
Open Source Initiative (OSI) is a non-profit corporation dedicated to managing
and promoting the Open Source Definition for the good of the community,
specifically through the OSI Certified Open Source Software certification mark
and program..
The basic idea behind open source is to read, redistribute, and modify the
source code for a piece of software, the software evolves. People improve it,
people adapt it, people fix bugs. We in the open source community have learned
that this rapid evolutionary process produces better software than the traditional
closed model, in which only a very few programmers can see the source and
everybody else must blindly use an opaque block of bits.
62. What is W3C.
Ans W3C (World Wide Web Consortium)
The organization responsible for managing standards for the WWW.
63. Define the following:
a. Open source software:
Open Source software which simply means any software certified by the OSI and
openly available with the source code.Open source software generally allows
anybody to make a new version of the software, port it to new operating systems and
processor architectures, share it with others or market.
b. Freeware
Software which is distributed free by the author. Although it is available for free, the
author retains the copyright, which means that it cannot be altered or sold.
c. Shareware.
Software distributed freely, but with certain conditions applying to it. Either the
software is released on a trial basis only, and must be registered after a certain period
of time, or in other cases no support can be offered with the software without
registering it. In some cases direct payment to the author is required.
d. Proprietary software.
Software which is privately owned or controlled is known as proprietary software.
Proprietary software is not free software or open source software as end-users
generally do not have the ability to:




Run the software for any purpose
Study and modify the software
Copy the software and provide it to third parties
Make and release improvements to the software
e. Localization.
localization is the adaptation of an object to a locality. An example is in software
localization, where the messages that a program presents to a user need to be
translated into various languages. Language localization refers to the process of
adapting a language for a specific country or region.
f. UNICODE.
It’s a Character coding system which is replacing older ASCII code thesesdays due to
its compatibility,size and scope .it is extensively used these days in Java,XML and
other languages.
64. Why Linux is popular now a days.
Ans Like Windows and Unix ,Linux is also an operating system developed Linus
Torvalds but this operating system was freely distributed as Open Source i.e
code is freely available to read ,edit and fix bugs.
Apart from the fact that it's freely distributed, Linux's functionality, adaptability
and robustness, has made it the main alternative for proprietary Unix and
Microsoft operating systems. IBM, Hewlett-Packard atre the top companies
which
has embraced Linux and support its ongoing development. It was
primarily adapted as a server platform.
65. What is Mozilla Firefox?
Ans Mozilla Firefox is a free web browser , from the Mozilla Application Suite,
managed by the Mozilla Corporation. It is the second-most popular browser
currently worldwide, after Internet Explorer. Firefox includes tabbed browsing, a
spell checker, incremental find, live bookmarking, a download manager, and an
integrated search system that uses the user's desired search engine.
66. Why Mozilla is different from other web browsers.
Ans An open-source XML/HTML browser have with dynamic image and table
resizing, quick insert and delete of table cells, improved CSS support.
67. Explain the webserver Apache.Where it is used.
Ans
The Apache HTTP Server is to develop and maintain an open-source web server
for modern operating systems including UNIX and Windows NT. The goal of
this project is to provide a secure, efficient and extensible server that provides
HTTP services in sync with the current HTTP standards.Apache has been the
most popular web server on the Internet since April 1996.
Uses of apache are:
Serves both static content and dynamic Web pages on the World Wide Web.
Apache provides environment to run web applications like java based and XML
68. Write short note on MySQL.
Ans MySQL is the world's most popular open source database software. It is a
structured query language like SQL used for managing database systems.Many
of the world's largest and fastest-growing organizations use MySQL to save time
and money powering their high-volume Web sites, business-critical systems and
packaged software -- including industry leaders such as Yahoo!, Alcatel-Lucent,
Google, Nokia.
.
69. Write brief note on Postgres.
Ans PostgreSQL is an object-relational database management system (ORDBMS). It is
released under as a free software. And like other open-source programs,
PostgreSQL is not controlled by any single company, but relies on a global
community of developers and companies to develop it.
70. What is Pango.
Ans
Pango is a free and open source computing library for rendering
internationalized texts in high quality. Pango has been integrated into most
Linux distributions. It most notably provides the rendering for text in the Mozilla
Firefox web browser Different font backends can be used, allowing crossplatform support.
71. What is Open office.
Ans The OpenOffice.org project aims "To create, as a community, the leading
international office suite that will run on all major platforms and provide access
to all functionality and data through open-component based APIs and an XMLbased file format like Microsoft Office.
72. Explain Tomcat,PHP,Python.
Ans Tomcat:
Apache Tomcat is an application server developed at the Apache Software
Foundation (ASF). To run java applications on web server It has its own internal
HTTP server and implements the Java Servlet and the JavaServer Pages (JSP)
specifications from Sun Microsystems, providing an environment for Java code
to run in cooperation with a web server.
PHP: short of Hypertext PreProcessor.It a server side side technolgy introduced
to design dynamic web pages like ASP,It is based on open source technolgy
under PHP licence to develop grahic and web applications.
It was written as a set of Common Gateway Interface (CGI) binaries in the C
programming language by the Danish/Greenlandic programmer Rasmus Lerdorf
in 1994, to replace a small set of Perl scripts he had been using to maintain his
personal homepage.
Python: Python is a multi-paradigm programming language (functional, object
oriented and imperative) which has a fully dynamic type system and uses
automatic memory management; it is thus similar to Perl, Ruby, Scheme, and Tcl.
The language has an open, community-based development model managed by
the non-profit Python Software Foundation.
73. What are the merits and demerits of open source.
Ans Merits :
 Source code is openly available.
 Freely distributed
 User is free to make changes and fix bugs without any licencing.
 Compatible and secured as per the application .
 One Common license requires to publish software i.e. GNU and gets poularity easily
in the market.
DeMerits:
 No sole authority for any sort of complaints as it is constantly developed and bugs
are fixed by any third person.



It can not be centrally managed and co-ordinated, and there are fewer "odd gaps" in
its development as such.
In case of closed source model new versions of the software are continually being
introduced, with lots of new features being added.
Revenue generation is very high due to target based applications.
74. Is freeware is same as free software ,If not, Why?
Ans No, Free software is distinct from freeware; freeware is proprietary software
made available free of charge. Everyone is free to sell copies of free software, to
use it commercially, and to charge for distribution and modifications. Because
anyone who has a copy may distribute the software at no cost, the software
generally is available at no cost. Free software business models are usually based
on adding value such as support, training, customisation, integration, or
certification like open source softwares are free softwares.
75. What are the two popular open source licenses ? How they are different.
Ans GNU Public License (GPL)
Most new open source software around these days uses this license, as does
Moodle. In a nutshell, the GPL says:





Anyone can download, use, modify and distribute this software
All modified versions must ALSO be under the GPL license
All copyright notices must be maintained, and all modifications must be
clearly marked
All distributions must include the full source code
There is no warranty on the software
Berkely Source Distribution (BSD)
The BSD license is even simpler - all it basically says is:




Anyone can download, use, modify and distribute this software in any
form
All existing copyright and usage notices must be kept in the software
There is no warranty on the software
The names of the original authors can't be used in promotion without
written permission from the original authors.
76. Write the difference between Adware and baitware.
Ans
Adware is any software program in which advertising banners are displayed
while the program is running.
Baitware: term is composed by bait and -ware and refers to a buggy freeware
software, released to deceptively attract users and drive them to commercial
products.
77. Differentiate between the following:
a. LAN and MAN
b. Microwave and Radiowave
c. Gopher and WWW
d. Star and Ring topology
e. Router and Gateway
f. Hub and Switch
g. Client and Server
h. CSMA/CD and token passing
i. Circuit switching and Message Switching.
j. Coaxial cables and optical fibers
k. Mobile Technology and Wireless Technology
l. SMS and 3G
m. XML and HTML
n. Hacker and Cracker.
o. Baseband and Broadband transmission
p. Domain and workgroup
Ans a.
LAN
a) Local Area Network. are privately
owned networks
b) Used to connect PC’s and workstation
within a building or computers in an
area upto 10 kms of range.
c) Speed of data transmission is not very
high
MAN
MAN-Metropolitan Area Network
Bigger version of LAN
Extends within metropolitan area.
Covers a group of nearby offices or
city
Speed of transmission is very high.
b.
Microwave
Parabolic antennas are mounted on
Radiowave
Waves are omni directional i.e.-travel in
towers to send a beam to other antenna. all directions from source to source
Higher the tower, greater is the range
destination need not be physically
aligned
Used for outdoor communication
Used for both indoor and outdoor
communication
Are subjected to weather easily .
Subject to interference.
c.
Gopher
A menu based browser that lets you
search for and retrieve desired
information on the internet
WWW
World wide web is a repository of
information containing a set of
programs , standards and protocols that
allows the multimedia and hypertext
files to be created , displayed and linked
on the internet.
Star
In a star topology, various nodes are
connected to a central dedicated
computer called hub of the star
If a node goes down, network keeps on
working without interruption
Ring
Ring topology has a large circular cable
and each node is connected to two of its
adjacent nodes, thus forming a ring
If one node fails whole network goes
down
d.
e.
Router
is a device joins similar networks but
can handle different types of
protocols .
A router works by looking at the IP
address in the packet and decides if it
is for internal use or if the packet
should move outside the network (to
the WAN).
f.
Gateway
is a system that joins two dissimilar
networks together
gateway acts as a conversion from one
protocol to another or in the case of VoIP
from the VoIP network to the POTS
network
Hub
Hub receives data and sends to all PC
connected through cables resulting in
collision.
Switch
In case of switch most of the network
traffic only goes where it needs to rather
than to every port.
Every computer connected to the hub
"sees" everything that every other
machine on the hub sees
Hub are less efficient and slower .
.It sends data according to the address
assigned and managing the network
traffic.
On busy networks this can make the
network significantly faster
g.
Client
Node refer to the computers attached
to the network and are seeking to
share the resources of the network.
Server
A computer that facilitates the sharing
of data , software and hardware
resources on the network is termed as
server
Every workstation is known as It is of high capacity to share clients at a
client.It is of lower configuration as common resource point.
compared to server.
h.
CSMA / CD
Traffic cannot be regulated
Waiting time cannot be determined
TOKEN PASSING
Traffic can be regulated
Waiting time can be determined before a
node transmits.
Nodes are given access on first come Nodes can be prioritized for getting
first serve basis .
access privilege.
Collision rate is high in high traffic.
Performance is good in low traffic.
No collision.
Even in low traffic the nodes have to
wait unnecessarily .
Circuit Switching
Message Switching
i.
Switching techniques of sending data
through
establishing
physical
connection between sender and
receiver.
Ex: Telephone communication
It’s a techniques based on store and
forward principle where data is first sent
to the switching office and then further
transferred accordingly.
Ex: Email
j.
Coaxial cables
Consists of a solid wire core
surrounded by one or more foil or
wire shield each separated by some
kind of plastic insulator.
Optical fibres
These are then strands of glass or glass
like material constructed to carry light
from one source at one end fiber to a
detector at other end
Bandwidth and data transmission is
in the form of electric signals which
is less as compared to optical fire is
less an
Offers electrical interference .
Bandwidth potentially very high.
Data transmission rate is also high due to
form of laser spectra.
optical fibres do not experience any
electrical interference.
Regenerators are required at every 2- Regenerators are required at least after
3 kms
50km
Used for cable T.V, telephone ,audio It can be used for high rate TV cable
channels etc.
channels,purposes of illumination ,in
sensors
k.
Mobile technology
It is the data communication without
the use of landlines. This may involve
cellular phones ,two way radio, fixed
wireless
,
,Laser
or
satellite
communication. Here the computing
device is continuously connected to
the base network.
Not all wireless technologies are
Wireless Technology
Mobile computing means that the
computing device is not continuously
connected to the base or the central
network .Mobile devices includes PDA’s
,laptop computer an many cell phones .
mobile.
a base location with or wireless
These products may communicate with
connection.
m.
XML
It is the subset of SGML where we are
free to define our own tags.
XML was designed to describe data
and to focus on what data is.
HTML
It is a language where we have
predefined tags .
HTML was designed to display data and
to focus on how data looks.
It is extensively used with other It is used as basic design platform for
languages like C# ,java to store and any web document and implements
send information.
scripting and server side technologies in
it.
n.
Hackers
Are the experts keeps on mastering
the
computer
and
related
technologies
Hackers constantly seek further
Crackers
A cracker is a person who breaks into or
otherwise violates the system integrity of
remote machines, with malicious intent
Crackers, having gained unauthorized
access, destroy vital data create viruses
knowledge, freely share what they
or do script attacks.
have discovered, and never, ever
intentionally damage data.
o.
Baseband
Baseband
is
a
bi-directional
transmission
Entire bandwidth of the cable is
consumed by a single signal
Broadband
broadband is a
unidirectional
transmission.
Broadband transmission, signals are
sent
on
multiple
frequencies,
allowing multiple signals to be sent
simultaneously.
Digital signals
Analog signals
No Frequency division multiplexing Frequency division multiplexing
possible
possible
Uses for short distance
Uses for long distance
p.
Domain
One or more computers are
servers
If you have a user account on the
domain, you can logon to any
computer on the domain.
There can be 100+ computers
The computers can be on different
local network
Workgroup
All Computers are peers.
Each computer has a set of accounts.
Typically not more then 20-30 computers
All computers must be on the same local
netork.
HOTS ( HIGH ORDER THINKING SKILLS)
78. The Netsavvy has set up a new office in the hill station Mussorie .It has 4 wings
as shown in the diagram below:
Wing A
Wing C
Wing B
Wing D
Center to center distance between various blocks
Wing A to Wing B
75m
Wing A to Wing C
150
Wing B to Wing C
25
Wing A to Wing D
50
Wing C to wing D
100
Number of computers in each wing
Wing A
25
Wing B
Wing C
Wing D
i)
50
125
10
Suggest the most suitable topology to network all the wings.
Ans
Most suitable topology to network all wings is star topology.
A
B
C
D
Total distance ==150+100+25 = 275
ii)
Suggest the most suitable place to house the server .Justify your choice.
Ans
C is the most suitable to house the server as it has max number of computers
and located centrally
iii)
Where and why should repeaters be used.
Ans
Repeaters is required between A-------B ,A----------C and C---------D where
distance is more than 50 ms
(iv)
The Mussorie office has to be linked with its headquarters in Mumbai
.suggest the most economical way to connect it. The organization is ready to
compromise on the speed of connectivity.
Ans
79. LML Organization has set up its new center at Mumbai for its office and web
based activities. It has 4 Blocks of buildings as shown in the diagram below:
Block A
Block C
Block D
Block B
Center to center distance 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
Block A
25
Block B
50
Block C
125
Block D
10
Number of Computers
a. Suggest a most suitable cable layout of connections between the Blocks.
b. Suggest the most suitable places (i.e. Block) to place the server of this organization
with a suitable reason.
c. Suggest the placement of the following devices with justification:
1. Repeater
2. Hub/Switch
d. The organization is planning to link its head office situated in City in a desert region
where cable connection is not feasible, suggest an economic way to connect it with
reasonably high speed?
Ans: a.
Block A
Block C
Block B
Block D
Cable Lyout is suggested to connect all computers on the network with minimum cable
length and cost. Therefore if we connect
A-B =50 m
A-C=90m
C-D=25m
i.e total cable length comes 165m
this is the best way to have cable connectivity in the above scenario.
Other way is through connecting block C i.e A-C and B-C and C-D
Which comes 90+ 150+25=265m
So considering the first case coaxial cables CAT 6 /5 can be placed .
b.
Server is placed as to get connected with maximum connectors in the center
location .Also Server rule 80-20 design rule also says that server should be
placed to balance the network traffic and data communication in the most easy
manner.
In the above scenario server should be placed in Block C
c.
Repeater is used to amplify the signals .It can be placed in between
Block A –Block C
Hub/Switches :Each building should have hub/switch to connect its local machines.
Block
AHub
Block
B Hub
Repeater
Block
C
Hub
Block
D
Hub
d. In that case organization can go for radio wave communication as radiowave
communication is cheaper and will serve the purpose of data communication in the best
manner as it has following features :
 Easy to generate
 Travel over long distances
 Used for communication both indoors & outdoors
Waves are Omni directional i.e.-travel in all directions from source to source destination
need not be physically aligned
80. Zercon Pvt Ltd. has decided to network all its offices spread in five buildings of
C.P.
(Shown below).
Building
2
Building
3
Building
1
Building
5
Center to center distance between various blocks
Between 1 and 2
50m
Between 2 and 3
50m
Between 3 and 4
120
Between 4 and 5
30
Between 3 and 5
75
Between 1 and 5
60
Between 2 and 5
50
Building
4
Between 3 and 4
50
Number of Computers
1
40
2
45
3
110
4
70
5
60
a) Suggest cable layout(s) for
connecting the buildings.
b) Where do you think , additional repeaters would be required by networking
buildings?
c) Company wants to minimize traffic . Which network device is/should be used for
this?
d) The company also has another office in the same city but at a distant location about
25-30 kms away. How can link be established with this building (i.e. suggest the
transmission medium).
Ans: a). Possible cable layouts are:
Building
1
Building
2
Building
5
Building
3
Building
4
Connecting Building 1-2-3-4-5
Total length =50+50+50+30=180ms
Best possible layout.
OR
Building 5---1—2—3---4 but length comes 280 which is high as compared to that.
b.
Repeaters could be placed between building 2 and 3 to amplify signals .
c.
Bridge as it does not broadcast data but sends data direct to its destination as per
machine address.
d.
In that case organization can go for radio wave communication as radiowave
communication is cheaper and will serve the purpose of data communication in
the best manner as it has following features :
Easy to generate
 Travel over long distances
 Used for communication both indoors & outdoors
Waves are omni directional i.e.-travel in all directions from source to source
destination need not be physically aligned

81. Rai Industries has set if its new center at Tri Nagar for its office and web based
activities. The company compound has 4 buildings as shown in the diagram
below:
R
Building
F
Building
H
Building
J
Building
Center to center distances between various buildings is as follows:
H Building to R Building
50 m
R Building to F Building
F Building to J Building
J Building to H Building
H Building to F Building
R Building to J Building
60 m
25 m
170 m
125 m
90 m
Number of Computers in each of the building is follows:
H Building
R Building
F Building
J Building
(a)
(b)
15
150
15
25
Suggest a cable layout of connections between the buildings.
Suggest the most suitable place (i.e., building) to house the server of this
organization with a suitable reason.
(c)
Suggest the placement of the following devices with justification:
(i)
Internet Connecting Device /Modem
(ii)
Switch
(d)
The organization is planning to link its sale counter suitable in various parts of
the same city. Which type of network out of LAN, MAN or WAN will be
formed? Justify your answer.
Ans: a)
Possible cable layout is :
Layout : 1
H-R-F-J
50+60+25 = 135m
Layout 2
50 + 60 + 90 = 200 m
Hence layout 1 is suggested.
b)
The most suitable place / block to house the server of this organization would be
Building R, as this building 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.
c)
i.) Modem should be placed at building R where server is housed.
ii.) Switch : Each building should have its switch to connect computers locally.
d)
MAN : Metro area network connectivity of computers of different types (LAN)
in a city.