Computer Network I - Sri Sukhmani Institute Of Engineering and

Computer Network I - Sri Sukhmani Institute Of Engineering and
Department: Computer Science and Engineering
Computer Network-I
Subject Code:
Affiliated to PTU, & Approved by AICTE
1. Write specifications of latest desktops and laptops.
2. Familiarization with Networking Components and devices: LAN
Adapters, Hubs, Switches, Routers etc.
3. Familiarization
with Transmission media and Tools: Co-axial
cable, UTP Cable, Crimping Tool, Connectors etc.
4. Preparing straight and cross cables.
5. Study
of various LAN topologies and their creation using
network devices, cables and computers.
6. Configuration of TCP/IP Protocols in Windows and Linux.
7. Implementation of file and printer sharing.
8. Designing and implementing Class A, B, and C Networks.
9. Subnet planning and its implementation.
10. Installation of ftp server and client.
Affiliated to PTU, & Approved by AICTE
List of Practical
Sr. No.
Write specifications of latest
desktops and laptops.
Familiarization with Networking
Components and devices: LAN
Adapters, Hubs, Switches,
Routers etc.
Familiarization with Transmission
media and Tools: Co-axial cable,
UTP Cable, Crimping Tool,
Connectors etc.
Preparing straight and cross
Study of various LAN topologies
and their creation using network
devices, cables and computers.
Configuration of TCP/IP Protocols
in Windows and Linux.
Implementation of file and printer
Designing and implementing
Class A, B, and C Networks.
Subnet planning and its
Installation of ftp server and
*Difference between Internet &
*Study of Client Server
*Learning beyond syllabus Difference between Internet & Intranet.
*Learning beyond syllabus Study of Client Server Architecture.
Affiliated to PTU, & Approved by AICTE
Experiment 1
AIM: Write specifications of latest desktops and laptops.
Block Diagram of Computer System and Explain its Various
Components:A computer can process data, pictures, sound and graphics. They can solve highly
complicated problems quickly and accurately. A computer as shown in Fig. Performs
basically five major computer operations or functions irrespective of their size and
make. These are:1) It accepts data or instructions by way of input,
2) It stores data,
3) It can process data as required by the user,
4) It gives results in the form of output, and
5) It controls all operations inside a computer.
We discuss below each of these Computer operations
Block Diagram of Computer System
1. Input: This is the process of entering data and programs in to the computer system.
You should know that computer is an electronic machine like any other machine which
takes as inputs raw data and performs some processing giving out processed data.
Therefore, the input unit takes data from us to the computer in an organized manner for
2. Storage: The process of saving data and instructions permanently is known as
storage. Data has to be fed into the system before the actual processing starts. It is
because the processing speed of Central Processing Unit (CPU) is so fast that the data
has to be provided to CPU with the same speed. Therefore the data is first stored in the
storage unit for faster access and processing. This storage unit or the primary storage of
the computer system is designed to do the above functionality. It provides space for
storing data and instructions.
The storage unit performs the following major functions:
• All data and instructions are stored here before and after processing.
• Intermediate results of processing are also stored here.
3. Processing: The task of performing operations like arithmetic and logical
operations is called processing. The Central Processing Unit (CPU) takes data and
instructions from the storage unit and makes all sorts of calculations based on the
instructions given and the type of data provided. It is then sent back to the storage unit.
4. Output: This is the process of producing results from the data for getting useful
information. Similarly the output produced by the computer after processing must also
be kept somewhere inside the computer before being given to you in human readable
form. Again the output is also stored inside the computer for further processing.
5. Control: The manner how instructions are executed and the above operations are
performed. Controlling of all operations like input, processing and output are performed
by control unit. It takes care of step by step processing of all operations inside the
In order to carry out the operations mentioned in the previous section the computer
allocates the task between its various functional units. The computer system is divided
into three separate units for its operation. They are
1) Arithmetic logical unit
2) Control unit.
3) Central processing unit.
Arithmetic Logical Unit (ALU) Logical Unit
Logical Unit: After you enter data through the input device it is stored in the primary
storage unit. The actual processing of the data and instruction are performed by
Arithmetic Logical Unit. The major operations performed by the ALU are addition,
subtraction, multiplication, division, logic and comparison. Data is transferred to ALU
from storage unit when required. After processing the output is returned back to storage
unit for further processing or getting stored.
Control Unit (CU)
The next component of computer is the Control Unit, which acts like the supervisor
seeing that things are done in proper fashion. Control Unit is responsible for co
ordinating various operations using time signal. The control unit determines the
sequence in which computer programs and instructions are executed. Things like
processing of programs stored in the main memory, interpretation of the instructions
and issuing of signals for other units of the computer to execute them. It also acts as a
switch board operator when several users access the computer simultaneously. Thereby
it coordinates the activities of computer’s peripheral equipment as they perform the
input and output.
Central Processing Unit (CPU)
The ALU and the CU of a computer system are jointly known as the central processing
unit. You may call CPU as the brain of any computer system. It is just like brain that
takes all major decisions, makes all sorts of calculations and directs different parts of the
computer functions by activating and controlling the operations.
Following are Hardware Component, Memory and its types, I/O Devices, Data Cables,
Hard Disk Drive, SCSI card, PCI & AGP Slots and ISA cards:-
Motherboard:The motherboard serves as a single platform to connect all of the parts of a computer together. A
motherboard connects CPU, memory, hard drives, optical drives, video card, sound card and other ports
and expansion cards directly or via cables. It can be considered as the backbone of a computer.
Block Diagram of Motherboard
Motherboard varies greatly in supporting various types of components.
Normally, a motherboard supports a single type of CPU and few types of memories.
Video Cards, Hard disks, Sound Cards have to be compatible with motherboard to
function properly.
Motherboards, cases and power supplies must be compatible to work properly together.
Popular Manufacturers
Computer-CPU:CPU is considered as the brain of the computer.
CPU performs all types of data processing operations.
It stores data, intermediate result and instructions (program).
It controls the operations of all parts of computer.
CPU itself has the following three components.
Memory or Storage Unit:
Control Unit
ALU (Arithmetic Logic Unit)
Computer Memory:A memory is just like a human brain. It is used to store data and instructions. Computer memory
is the storage space in computer where data is to be processed and instructions required for
processing are stored.
The memory is divided into large number of small parts. Each part is called cell. Each location or
cell has a unique address, which varies from zero to memory size minus one.
For example, if computer has 64k words, then this memory unit has 64 * 1024=65536 memory
location. The address of these locations varies from 0 to 65535.
Memory is primarily of three types:
Cache Memory
Primary Memory/Main Memory
Secondary Memory
Cache Memory
Cache memory is a very high speed semiconductor memory, which can speed up CPU. It acts as
a buffer between the CPU and main memory.
It is used to hold those parts of data and program which are most frequently used by CPU. The
parts of data and programs are transferred from disk to cache memory by operating system, from
where CPU can access them.
Cache memory is faster than main memory.
It consumes less access time as compared to main memory.
It stores the program that can be executed within a short period of time.
It stores data for temporary use.
Cache memory has limited capacity.
It is very expensive.
Primary Memory (Main Memory)
Primary memory holds only those data and instructions on which computer is currently working.
It has limited capacity and data gets lost when power is switched off.
It is generally made up of semiconductor device. These memories are not as fast as registers. The
data and instructions required to be processed earlier reside in main memory. It is divided into
two subcategories RAM and ROM.
Characteristic of Main Memory
These are semiconductor memories.
It is known as main memory.
Usually volatile memory.
Data is lost in case power is switched off.
It is working memory of the computer.
Faster than secondary memories.
A computer cannot run without primary memory.
Secondary Memory
This type of memory is also known as external memory or non-volatile. It is slower than main
memory. These are used for storing Data/Information permanently.
CPU directly does not access these memories, instead they are accessed via input-output
routines. Contents of secondary memories are first transferred to main memory and then CPU
can access it. For example, disk, CD-ROM, DVD, etc.
Characteristics of Secondary Memory
These are magnetic and optical memories.
It is known as backup memory.
It is non-volatile memory.
Data is permanently stored even if power is switched off.
It is used for storage of the data in the computer.
Computer may run without secondary memory.
Slower than primary memories.
Hard Disk Drive
INPUT DEVICES:Following are few of the important input devices, which are used in Computer Systems:
Light pen
Magnetic Ink Card Reader (MICR)
Bar Code Reader
Most common and very popular input device is keyboard. The keyboard helps in inputting the
data to the computer. The layout of the keyboard is like that of traditional typewriter, although
there are some additional keys provided for performing some additional functions.
Keyboards are of two sizes 84 keys or 101/102 keys, but now 104 keys or 108 keys keyboard is
also available for Windows and Internet.
The keys are following
Sr. No.
Typing Keys
Numeric Keypad
Function Keys
Control keys
Special Purpose Keys
These keys include the letter keys (A-Z) and digits keys (0-9)
which generally give same layout as that of typewriters.
It is used to enter numeric data or cursor movement.
Generally, it consists of a set of 17 keys that are laid out in the
same configuration used by most adding machine and
The twelve functions keys are present on the keyboard. These
are arranged in a row along the top of the keyboard. Each
function key has unique meaning and is used for some specific
These keys provide cursor and screen control. It includes four
directional arrow key. Control keys also include Home, End,
Insert, Delete, Page Up, Page Down, Control(Ctrl),
Alternate(Alt), Escape(Esc).
Keyboard also contains some special purpose keys such as
Enter, Shift, Caps Lock, Num Lock, Space bar, Tab, and Print
Mouse is most popular Pointing device. It is a very famous cursor-control device. It is a small
palm size box with a round ball at its base which senses the movement of mouse and sends
corresponding signals to CPU on pressing the buttons.
Generally, it has two buttons called left and right button and scroll bar is present at the mid.
Mouse can be used to control the position of cursor on screen, but it cannot be used to enter text
into the computer.
Easy to use
Not very expensive
Moves the cursor faster than the arrow keys of keyboard.
Joystick is also a pointing device, which is used to move cursor position on a monitor screen. It
is a stick having a spherical ball at its both lower and upper ends. The lower spherical ball moves
in a socket. The joystick can be moved in all four directions.
The function of joystick is similar to that of a mouse. It is mainly used in Computer Aided
Designing (CAD) and playing computer games.
Light Pen
Light pen is a pointing device, which is similar to a pen. It is used to select a displayed menu
item or draw pictures on the monitor screen. It consists of a photocell and an optical system
placed in a small tube.
When light pen's tip is moved over the monitor screen and pen button is pressed, its photocell
sensing element detects the screen location and sends the corresponding signal to the CPU.
Scanner is an input device, which works more like a photocopy machine. It is used when some
information is available on a paper and it is to be transferred to the hard disc of the computer for
further manipulation.
Scanner captures images from the source which are then converted into the digital form that can
be stored on the disc. These images can be edited before they are printed.
Magnetic Ink Card Reader (MICR)
MICR input device is generally used in banks because of a large number of cheques to be
processed everyday. The bank's code number and cheque number are printed on the cheques with
a special type of ink that contains particles of magnetic material that are machine readable.
This reading process is called Magnetic Ink Character Recognition (MICR). The main advantage
of MICR is that it is fast and less error prone.
Bar Code Readers
Bar Code Reader is a device used for reading bar coded data (data in form of light and dark
lines). Bar coded data is generally used in labelling goods, numbering the books, etc. It may be a
hand-held scanner or may be embedded in a stationary scanner.
Bar Code Reader scans a bar code image, converts it into an alphanumeric value, which is then
fed to the computer to which bar code reader is connected.
OUTPUT DEVICES:Following are few of the important output devices, which are used in Computer Systems:
Graphic Plotter
Monitor commonly called as Visual Display Unit (VDU) is the main output device of a
computer. It forms images from tiny dots, called pixels that are arranged in a rectangular form.
The sharpness of the image depends upon the number of the pixels.
There are two kinds of viewing screen used for monitors:
Cathode-Ray Tube (CRT)
Flat-Panel Display
Cathode-Ray Tube (CRT) Monitor
In the CRT, display is made up of small picture elements called pixels for short. The smaller the
pixels, the better the image clarity or resolution. It takes more than one illuminated pixel to form
whole character, such as the letter 'e' in the word help.
A finite number of characters can be displayed on a screen at once. The screen can be divided
into a series of character boxes - fixed location on the screen where a standard character can be
Most screens are capable of displaying 80 characters of data horizontally and 25 lines vertically.
There are some disadvantages of CRT:
Large in Size
High power consumption
Flat-Panel Display Monitor
The flat-panel display refers to a class of video devices that have reduced volume, weight and
power requirement compared to the CRT. You can hang them on walls or wear them on your
wrists. Current uses for flat-panel displays include calculators, video games, monitors, laptop
computer, graphics display.
The flat-panel display is divided into two categories:
Emissive Displays - The emissive displays are devices that convert electrical energy into
light. Example is plasma panel and LED (Light-Emitting Diodes).
Non-Emissive Displays - The Non-emissive displays use optical effects to convert
sunlight or light from some other source into graphics patterns. Example is LCD (LiquidCrystal Device)
Printer is the most important output device, which is used to print information on paper.
There are two types of printers:
Impact Printers
Non-Impact Printers
Impact Printers
The printers that print the characters by striking against the ribbon and onto the paper, are called
impact printers.
Characteristics of Impact Printers are the following:
Very low consumable costs
Impact printers are very noisy
Useful for bulk printing due to low cost
There is physical contact with the paper to produce an image
These printers are of two types:
Character printers
Line printers
Character Printers:
Character Printers are printers, which print one character at a time.
These are of further two types:
Dot Matrix Printer (DMP)
Daisy Wheel
Dot Matrix Printer
In the market, one of the most popular printers is Dot Matrix Printer because of their ease of
printing features and economical price. Each character printed is in form of pattern of Dot's and
head consists of a Matrix of Pins of size (5*7, 7*9, 9*7 or 9*9) which comes out to form a
character that is why it is called Dot Matrix Printer.
Widely Used
Other language characters can be printed
Slow Speed
Poor Quality
Daisy Wheel
Head is lying on a wheel and Pins corresponding to characters are like petals of Daisy (flower
name) that is why it is called Daisy Wheel Printer. These printers are generally used for wordprocessing in offices which require a few letters to be sent here and there with very nice quality
More reliable than DMP's
Better quality
The fonts of character can be easily changed.
Slower than DMP's
More expensive than DMP's
Non-impact Printers
The printers that print the characters without striking against the ribbon and onto the paper are
called Non-impact Printers. These printers print a complete page at a time, also called as Page
These printers are of two types:
Laser Printers
Inkjet Printers
Characteristics of Non-impact Printers:
Faster than impact printers.
They are not noisy.
High quality.
Support many fonts and different character size.
Laser Printers
These are non-impact page printers. They use laser lights to produce the dots needed to form the
characters to be printed on a page.
Very high speed.
Very high quality output.
Gives good graphics quality.
Supports many fonts and different character sizes.
Cannot be used to produce multiple copies of a document in a single printing.
Inkjet Printers
Inkjet printers are non-impact character printers based on a relatively new technology. They print
characters by spraying small drops of ink onto paper. Inkjet printers produce high quality output
with presentable features.
They make less noise because no hammering is done and these have many styles of printing
modes available. Colour printing is also possible. Some models of Inkjet printers can produce
multiple copies of printing also.
High quality printing
More reliable
Expensive as cost per page is high
Slow as compared to laser printer
Computer Port:A computer port is a physical docking point using which an external device can be
connected to the computer.
A computer port can also be programmatic docking point through which information
flows from a program to computer or over the internet.
External devices are connected to a computer using cables and ports.
Ports are slots on the motherboard into which a cable of external device is plugged in.
Examples of external devices attached via ports are mouse, keyboard, monitor,
microphone, speakers, etc.
Following are few important types of ports:
Serial Port
Used for external modems and older computer mouse.
Two versions: 9 pin, 25 pin model.
Data travels at 115 kilobits per second.
Parallel Port
Used for scanners and printers
Also called printer port.
25 pin model.
Also known as IEEE 1284-compliant Centronics port.
PS/2 Port
Used for old computer keyboard and mouse
Also called mouse port.
Most of the old computers provide two PS/2 ports, each for mouse and keyboard.
Also known as IEEE 1284-compliant Centronics port.
Universal Serial Bus (or USB) Port
Can connect all kinds of external USB devices such as external hard disk, printer,
scanner, mouse, keyboard, etc.
Introduced in 1997.
Most of the computers provide two USB ports as minimum.
Data travels at 12 megabits per second.
USB compliant devices can get power from a USB port.
VGA Port
Connects monitor to a computer's video card.
Have 15 holes.
Similar to serial port connector but serial port connector has pins, it has holes.
Power Connector
Three-pronged plug
Connects to the computer's power cable that plugs into a power bar or wall socket.
Connects a PC's modem to the telephone network.
Ethernet Port
Connects to a network and high speed Internet.
Connects network cable to a computer.
This port resides on an Ethernet Card.
Data travels at 10 megabits to 1000 megabits per second depending upon the network
Game Port
Connect a PC to a joystick.
Now replaced by USB.
Digital Video Interface, DVI port
Connects a Flat panel LCD monitor to the computer's high-end video graphic cards.
Very popular among video card manufacturers.
AGP Slot:-Short for Accelerated Graphics Port, AGP is an advanced port designed for Video
cards and 3D accelerators. Designed by Intel and introduced in August of 1997, AGP introduces
a dedicated point-to-point channel that allows the graphics controller direct access the system
memory. Below is an illustration of what the AGP slot may look like on your motherboard.
PCI Slot:Short for Peripheral Component Interconnect, PCI was introduced by Intel in 1992, revised in
1993 to version 2.0, and later revised in 1995 to PCI 2.1 and is as an expansion to the ISA bus.
The PCI bus is a 32-bit (133MBps) computer bus that is also available as a 64-bit bus and was
the most commonly found and used computer bus in computers during the late 1990's and early
2000's. Unlike, ISA and earlier expansion cards, PCI follow the PnP specification and therefore
do not require any type of jumpers or dip switches. Below is an example of what the PCI slot
looks like on a motherboard.
Acer Laptop Specification
Windows 8 - Intel Core i3 (i3 - 3217U, 1.80 GHz, 3 MB) - 35.6 cm (14") LED - 16:9 HD Active Matrix TFT Color LCD - Intel HD 4000 - 4 GB DDR3L SDRAM - 500 GB Serial ATA DVD - Writer - Color Black - Weight (Approximate) 2.30 kg - Maximum Battery Run Time 5
Windows 8
Operating System
Processor & Chipset
Processor Manufacturer
Processor Type
Core i3
Processor Model
Processor Speed
1.80 GHz
Processor Core
Dual-core (2 Core)
Standard Memory
4 GB
Maximum Memory
8 GB
Memory Technology
Memory Card Reader
Memory Card Supported
Secure Digital (SD) Card
Hard Drive Capacity
500 GB
Hard Drive Interface
Serial ATA
Optical Drive Type
Display & Graphics
Screen Size
35.6 cm (14")
Display Screen Type
Active Matrix TFT Color LCD
Screen Mode
Screen Resolution
1366 x 768
Backlight Technology
Touch screen
Multi-touch Screen
Graphics Controller ManufacturerIntel
Graphics Controller Model
HD 4000
Graphics Memory Technology DDR3 SDRAM
Graphics Memory Accessibility Shared
Network & Communication
Wireless LAN Standard
IEEE 802.11b/g/n
Ethernet Technology
Gigabit Ethernet
Built-in Devices
Finger Print Reader
Total Number of USB Ports
Number of USB 2.0 Ports
Number of USB 3.0 Ports
Network (RJ-45)
Operating System
Windows 8
Operating System Architecture 64-bit
Input Devices
Pointing Device Type
Battery Information
Number of Cells
Battery Chemistry
Lithium Ion (Li-Ion)
Battery Capacity
2500 m Ah
Maximum Battery Run Time
5 Hour
Power Description
Maximum Power Supply Wattage 65 W
Physical Characteristics
Height (Front)
14.40 mm
Height (Rear)
25.90 mm
25.9 mm
344 mm
245 mm
Weight (Approximate)
2.30 kg
Experiment No 2.
AIM:-Familiarization with Networking Components and devices:
LAN Adapters, Hubs, Switches, and Routers etc.
LAN Adapter:An expansion board that is used to connect a computer or computing device to a network. LAN
adapter is the most common and generic alternate name for a Network Interface Card (NIC).
However, many similar products, such as a Wireless USB LAN Adapter is also called a LAN
Wireless USB LAN adapter:A high-speed wireless network card that is used to access a network through a USB port on a
computer or laptop. Most wireless USB LAN adapters look like small USB flash drives and
usually are based on the 802.11g standard which provides a data rate up to 54-Mbps in a wireless
LAN environment. Some wireless USB LAN adapters may also support the 802.11b standard. A
wireless USB LAN adapter basically enables you to share files, folders, printers, other network
resources and Internet access.
Network Hub:Definition: In computer networking, a hub is a small, simple, inexpensive device that joins
multiple computers together. Many network hubs available today support the Ethernet standard.
Other types including USB hubs also exist, but Ethernet is the type traditionally used in home
Technically speaking, two different types of hubs exist:
Passive hubs do not amplify the electrical signal of incoming packets before broadcasting them
out to the network. Active hubs, on the other hand, do perform this amplification, as does a
different type of dedicated network device called a repeater. Some people use the terms
concentrator when referring to a passive hub and multiport repeater when referring to an
active hub.
Network switch:A network switch (sometimes known as a switching hub) is a computer networking device that
is used to connect devices together on a computer network. A switch is considered more
advanced than a hub because a switch will only send a message to the device that needs or
requests it, rather than broadcasting the same message out of each of its ports. [1]
A switch is a multi-port network bridge that processes and forwards data at the data link layer
(layer 2) of the OSI model. Some switches have additional features, including the ability to route
packets. These switches are commonly known as layer-3 or multilayer switches.
Router:Router: Routers are devices (computers) containing software that help in determining the best
path out of the available paths, for a particular transmission. They consist of a combination of
hardware and software. The hardware includes the physical interfaces to the various networks in
the internet work. The two main pieces of software in a router are the operating system and the
routing protocol.
Routers use logical and physical addressing to connect two or more logically separate networks.
They accomplish this connection by organizing the large network into logical network segments
or sub-networks. Each of these sub networks is given a logical address. This allows the networks
to be separate but still access each other and exchange data when necessary. Data is grouped into
packets, or blocks of data. Each packet, in addition to having a physical device address, has a
logical network address.
Routers are frequently used to interconnect identical networks as well as to interconnect
networks with different types of hardware.
How Routers Works
Routers are interconnectivity devices that are used to transfer the datum packets along networks
by visualizing the networks path. Routers visualizing the networks path to many networks such
as Electronic networks, Transport networks and phone networks. Two ways are exist for routers
operation using either control plane or forwarding plane. In control plane the router sends the
precise data packets to their specific location. On the other hand in forwarding plane router does
not remember the sending or receiving information about the packets.
Advantages of Routers
Routers route the data in an organized way. Routers generate a reliable connection between
hosts. Routers is used for alternatively incase the main is fail to transfer data.
Experiment No 3.
AIM:-Familiarization with Transmission media and Tools: Co-axial
cable, UTP Cable, Crimping Tool, Connectors etc.
What is transmission media?
Transmission media is a pathway that carries the information from sender to receiver. We use
different types of cables or waves to transmit data. Data is transmitted normally through
electrical or electromagnetic signals.
An electrical signal is in the form of current. An electromagnetic signal is series of
electromagnetic energy pulses at various frequencies. These signals can be transmitted through
copper wires, optical fibers, atmosphere, water and vacuum Different Medias have different
properties like bandwidth, delay, cost and ease of installation and maintenance. Transmission
media is also called Communication channel.
Types of Transmission Media
1. Wired or Guided Media or Bound Transmission Media
2. Wireless or Unguided Media or Unbound Transmission Media
Wired or Guided Media or Bound Transmission Media: Bound transmission media are the
cables that are tangible or have physical existence and are limited by the physical geography.
Popular bound transmission media in use are twisted pair cable, co-axial cable and fiber optical
cable. Each of them has its own characteristics like transmission speed, effect of noise, physical
appearance, cost etc.
Wireless or Unguided Media or Unbound Transmission Media: Unbound transmission
media are the ways of transmitting data without using any cables. These media are not bounded
by physical geography. This type of transmission is called Wireless communication. Nowadays
wireless communication is becoming popular. Wireless LANs are being installed in office and
college campuses. This transmission uses Microwave, Radio wave, Infra red are some of popular
unbound transmission media.
Guided Transmission Media
Types of Twisted Pair
The two types of twisted pairs are:
1. Unshielded twisted pair (UTP) ,2. Shielded twisted pair (STP)
1. Unshielded Twisted Pair (UTP)
It consists of colour-coded copper wires, but does not include any foil or braiding as insulator to
protect against interference.
Wire pairs within each cable have varied amounts of twists per foot to produce cancellation.
There are different categories of UTP.
The following table shows the UTP categories, the no. of pairs in each, and the grade of cable
each uses and how they are implemented.
2. Shielded Twisted Pair (STP)
STP is made up of pairs of copper wires that are twisted together.
The pairs are covered in a foil or braided mesh, as well as outer PVC jacket.
This foil or mesh prevents the penetration of electromagnetic noise and eliminate cross talk.
This shielding must be grounded to prevent the foil or braided mesh from becoming a magnet for
Advantage of STP over UTP
STP is less susceptible to noise as compared to UTP and therefore reduces the cross talk and
Disadvantages of STP
1. It must be properly grounded.
2. It is more expensive than UTP.
3. It is difficult to terminate.
Advantages of Twisted pair cable
1. It can be used to carry both analog and digital data.
2. It is relatively easy to implement and terminate.
3. It is the least expensive media of transmission for short distances.
4. If portion of a twisted pair cable is damaged it does not effect the entire network.
Disadvantages of Twisted pair cable
1. It offers poor noise immunity as a result signal distortion is more?
2. Attenuation is very high.
3. It supports lower bandwidth as compared to other Medias. It supports 10 mbps upto a distance
of 100 meters on a 10BASE-T.
4. It offers very poor security and is relatively easy to tap.
5. Being thin in size, they are likely to break easily.
Coaxial Cable
Coaxial cable has two wires of copper. The core wire lies in center and is made of solid
conductor. Core is enclosed in an insulating sheath. Over the sheath the second wire is wrapped
around and that too in turn encased by insulator sheath. This all is covered by plastic cover.
Because of its structure coax cables are capable of carrying high frequency signals than that of
twisted pair cables. The wrapped structure provides it a good shield against noise and cross talk.
Coaxial cables provide high bandwidth rates of up to 450 mbps.
There are three categories of Coax cables namely, RG-59 (Cable TV), RG-58 (Thin Ethernet)
and RG-11 (Thick Ethernet. RG stands for Radio Government .
Cables are connected using BNC connector and BNC-T. BNC terminator is used to terminate the
wire at the far ends.
Fiber-Optics Cable
A cable with central glass tube covered with protective shield which transmit data using
photons is fiber optics cable. These cables transmit data via concentrated bursts of laser beams
which are carried through bundles of hair thin glass fibers.
They have advantages over electronic cables in transmission speed and volume. This
technology has revolutionized telecommunication applications which used electronic cables.
Fiber optics cables as free from electro-magnetic interference as well as wire tapping. fiber
optics cable considered a broad band communication channel
Unguided Transmission Media:Unguided transmission media extend beyond the limiting confines of cabling. They provide an
excellent Communication Networks alternative for WANS. The lack of physical restrictions
provides larger bandwidth as well as wide area capabilities. Unbound media typically operate at
very high frequencies. The three types of unbound transmission media are:
Radio wave.
Micro wave.
Radiowaves Transmission
Although Radio waves are prevalent and well
understood, we are just beginning to realize their enormous potential as a networking medium.
Radio waves can operate on a single or multiple frequency bands.
Radiowaves are omni directional i.e. they travel in all the directions from the source. Because of
this property, transmitter and receiver need not to be aligned. Radiowaves can penetrate
buildings easily, so they are widely use for communication both indoors outdoors.
At high frequencies, radiowaves tends to travel in straight line and bounce off the
obstacles. They are also absorbed by rain. Radiowaves me widely used for AM and FM radio,
television, cordless telephone, cellular phones, paging and wireless LAN.
Microwave Transmission
Microwaves have been used in data communications for a long time. They have a higher
frequency than radio waves and therefore can handle larger amounts of data.
Microwave transmission is line of sight transmission. The transmit station must be in visible
contact with the receive station. This sets a limit on the distance between stations depending on
the local geography. Typically the line of sight due to the Earth's curvature is only 50 km to the
horizon! Repeater stations must be placed so the data signal can hop, skip and jump across the
country. microwave circuits considered a broad band communication channel. Microwaves
operate at high operating frequencies of 3 to 10 GHz. This allows them to carry large quantities
of data due to their large bandwidth.
List the Advantages of microwaves.
a. They require no right of way acquisition between towers.
b. They can carry high quantities of information due to their high operating frequencies.
c. Low cost land purchase: each tower occupies only a small area.
d. High frequency/short wavelength signals require small antennae.
Disadvantages of Microwaves
a. Attenuation by solid objects: birds, rain, snow and fog.
b. Reflected from flat surfaces like water and metal.
c. Diffracted (split) around solid objects.
d. Refracted by atmosphere, thus causing beam to be projected away from receiver.
Infrared offers a great unbound photonic solution. Like fiber-optic cabling, infrared
communications use light, so they are not bound by the limitations of electricity.
Crimping tool
A crimping tool is a tool designed to crimp or connect a connector to the end of a cable. For
example, network cables and phone cables are created using a crimping tool to connect the RJ-45
and RJ-11 connectors to the end of the cable. In the example below picture, this crimper is
capable of crimping a RJ-11 (6-Pin) and RJ-45 (8-Pin) connectors and also includes a wire cutter
near the handles that can be used to cut phone or CAT5 cable.
RJ-45 Connecter
The RJ-45 connector is a form of telephone connector. It sees its most frequent use as a localarea network connector, and is frequently referred to simply as an Ethernet connector.
BNC Connecter
This connector is commonly used on a Token Ring network. BNC is also short for Bayonet Nut
Connector or British Naval/Navy Connector although more appropriately known as the
Bayonet Neill Concelman. In the picture to the right, is an example of a BNC connector on the
end of a coaxial cable.
Experiment No 4.
AIM:-Preparing straight and cross cables.
Straight-Through Wired Cables
Straight-Through refers to cables that have the pin assignments on each end of the cable. In other
words Pin 1 connector A goes to Pin 1 on connector B, Pin 2 to Pin 2 ect. Straight-Through
wired cables are most commonly used to connect a host to client. When we talk about cat5e
patch cables, the Straight-Through wired cat5e patch cable is used to connect computers, printers
and other network client devices to the router switch or hub (the host device in this instance).
Crossover Wired Cables
An Ethernet crossover cable is a type of Ethernet cable used to connect computing devices
together directly. Normal straight through or patch cables were used to connect from a host
network interface controller (a computer or similar device) to a network switch, hub or router. A
cable with connections that "cross over" was used to connect two devices of the same type: two
hosts or two switches to each other.
Experiment No 5.
AIM:-Study of various LAN topologies and their creation using
network devices, cables and computers.
Types of Topology:-
Bus topology
Bus Topology is the simplest of network topologies. In this type of topology, all the nodes
(computers as well as servers) are connected to the single cable (called bus), by the help of
interface connectors. This central cable is the backbone of the network and is known as Bus (thus
the name). Every workstation communicates with the other device through this Bus.
Advantages (benefits) of Bus Topology
1) It is easy to set-up and extend bus network.
2) Cable length required for this topology is the least compared to other networks.
3) Bus topology costs very less.
4) Linear Bus network is mostly used in small networks. Good for LAN.
Disadvantages (Drawbacks) of Bus Topology
1) There is a limit on central cable length and number of nodes that can be connected.
2) Dependency on central cable in this topology has its disadvantages. If the main cable (i.e. bus
) encounters some problem, whole network breaks down.
3) Proper termination is required to dump signals. Use of terminators is must.
4) It is difficult to detect and troubleshoot fault at individual station.
5) Maintenance costs can get higher with time.
6) Efficiency of Bus network reduces, as the number of devices connected to it increases.
7) It is not suitable for networks with heavy traffic.
8) Security is very low because all the computers receive the sent signal from the source.
Star topology
In Star topology, all the components of network are connected to the central device called
“hub” which may be a hub, a router or a switch. Unlike Bus topology (discussed earlier), where
nodes were connected to central cable, here all the workstations are connected to central device
with a point-to-point connection. So it can be said that every computer is indirectly connected to
every other node by the help of “hub”.
Star Topology Diagram
Advantages of Star Topology
1) As compared to Bus topology it gives far much better performance, signals don’t necessarily
get transmitted to all the workstations.
2) Easy to connect new nodes or devices. In star topology new nodes can be added easily
without affecting rest of the network. Similarly components can also be removed easily.
3) Centralized management. It helps in monitoring the network.
4) Failure of one node or link doesn’t affect the rest of network. At the same time its easy to
detect the failure and troubleshoot it.
Disadvantages of Star Topology
1) Too much dependency on central device has its own drawbacks. If it fails whole network
goes down.
2) The use of hub, a router or a switch as central device increases the overall cost of the
3) Performance and as well number of nodes which can be added in such topology is depended
on capacity of central device.
Ring Topology
In Ring Topology, all the nodes are connected to each-other in such a way that they make a
closed loop. Each workstation is connected to two other components on either side, and it
communicates with these two adjacent neighbors. Data travels around the network, in one
direction. Sending and receiving of data takes place by the help of TOKEN.
Advantages of Ring Topology
1) This type of network topology is very organized. Each node gets to send the data when it
receives an empty token. This helps to reduces chances of collision. Also in ring topology all
the traffic flows in only one direction at very high speed.
2) Even when the load on the network increases, its performance is better than that of Bus
3) There is no need for network server to control the connectivity between workstations.
4) Additional components do not affect the performance of network.
5) Each computer has equal access to resources.
Disadvantages of Ring Topology
1) Each packet of data must pass through all the computers between source and destination.
This makes it slower than Star topology.
2) If one workstation or port goes down, the entire network gets affected.
3) Network is highly dependent on the wire which connects different components.
4) MAU’s and network cards are expensive as compared to Ethernet cards and hubs.
Mesh Topology
In a mesh network topology, each of the network node, computer and other devices, are
interconnected with one another. Every node not only sends its own signals but also relays data
from other nodes. In fact a true mesh topology is the one where every node is connected to every
other node in the network. This type of topology is very expensive as there are many redundant
connections, thus it is not mostly used in computer networks. It is commonly used in wireless
networks. Flooding or routing technique is used in mesh topology.
Mesh Topology Diagram
Advantages of Mesh topology
1) Data can be transmitted from different devices simultaneously. This topology can withstand
high traffic.
2) Even if one of the components fails there is always an alternative present. So data transfer
doesn’t get affected.
3) Expansion and modification in topology can be done without disrupting other nodes.
Disadvantages of Mesh topology
1) There are high chances of redundancy in many of the network connections.
2) Overall cost of this network is way too high as compared to other network topologies.
3) Set-up and maintenance of this topology is very difficult. Even administration of the network
is tough.
Tree Topology
Tree Topology integrates the characteristics of Star and Bus Topology. Earlier we saw how in
Physical Star network Topology, computers (nodes) are connected by each other through central
hub. And we also saw in Bus Topology, work station devices are connected by the common
cable called Bus. After understanding these two network configurations, we can understand tree
topology better. In Tree Topology, the numbers of Star networks are connected using Bus. This
main cable seems like a main stem of a tree, and other star networks as the branches. It is also
called Expanded Star Topology. Ethernet protocol is commonly used in this type of topology.
The diagram below will make it clear.
Tree Topology
Advantages of Tree Topology
1. It is an extension of Star and bus Topologies, so in networks where these topologies can't be
implemented individually for reasons related to scalability, tree topology is the best alternative.
2. Expansion of Network is possible and easy.
3. Here, we divide the whole network into segments (star networks), which can be easily
managed and maintained.
Disadvantages of Tree Topology
1. Because of its basic structure, tree topology, relies heavily on the main bus cable, if it breaks
whole network is crippled.
2. As more and more nodes and segments are added, the maintenance becomes difficult.
3. Scalability of the network depends on the type of cable used.
Hybrid Topology
Before starting about Hybrid topology, we saw that a network topology is a connection of
various links and nodes, communicating with each other for transfer of data. We also saw
various advantages and disadvantages of Star, Bus, Ring, Mesh and Tree topologies.
Now lets discuss what Hybrid Network topology is and why it finds its application in Wide Area
Networks. Hybrid, as the name suggests, is mixture of two different things. Similarly in this type
of topology we integrate two or more different topologies to form a resultant topology which has
good points (as well as weaknesses) of all the constituent basic topologies rather than having
characteristics of one specific topology. This combination of topologies is done according to the
requirements of the organization.
For example, if there exists a ring topology in one office department while a bus topology in
another department, connecting these two will result in Hybrid topology. Remember connecting
two similar topologies cannot be termed as Hybrid topology. Star-Ring and Star-Bus networks
are most common examples of hybrid network.
Let's see the benefits and drawbacks of this networking architecture
Hybrid Network Topology Image
Advantages of Hybrid Network Topology
1) Reliable: Unlike other networks, fault detection and troubleshooting is easy in this type of
topology. The part in which fault is detected can be isolated from the rest of network and
required corrective measures can be taken, WITHOUT affecting the functioning of rest of the
2) Scalable: Its easy to increase the size of network by adding new components, without
disturbing existing architecture.
3) Flexible: Hybrid Network can be designed according to the requirements of the organization
and by optimizing the available resources. Special care can be given to nodes where traffic is
high as well as where chances of fault are high.
4) Effective: Hybrid topology is the combination of two or more topologies, so we can design it
in such a way that strengths of constituent topologies are maximized while there weaknesses are
neutralized. For example we saw Ring Topology has good data reliability (achieved by use of
tokens) and Star topology has high tolerance capability (as each node is not directly connected to
other but through central device), so these two can be used effectively in hybrid star-ring
Disadvantages of Hybrid Topology
1) Complexity of Design: One of the biggest drawback of hybrid topology is its design. Its not
easy to design this type of architecture and its a tough job for designers. Configuration and
installation process needs to be very efficient.
2) Costly Hub: The hubs used to connect two distinct networks, are very expensive. These hubs
are different from usual hubs as they need to be intelligent enough to work with different
architectures and should be function even if a part of network is down.
3) Costly Infrastructure: As hybrid architectures are usually larger in scale, they require a lot
of cables, cooling systems, sophisticate network devices, etc.
Experiment No 6.
AIM:-Configuration of TCP/IP Protocols in Windows and Linux
Configuration of TCP/IP protocols in Windows XP & Windows 7:For Windows XP
Step 1
Click Start->Control Panel->select and double click Network and internet connections>select and double click Network Connections.
Step 2
Double-click the Local Area Connection icon; highlight Internet Protocol (TCP/IP) tab in the
Local Area Connection Properties window that appears:
Step 3
Double click it or click Properties. The TCP/IP Properties window will display.
Step 4
Now you have two ways to configure the TCP/IP protocol below:
1. Assigned by DHCP Sever
Select Obtain an IP address automatically and Obtain DNS Server address automatically,
as shown in the figure below. These may be selected by default. Then click OK to save setting.
2. Assigned manually
1) Select Use the following IP address, as shown in the following figure.
If the router’s LAN IP address is, please type in IP address 192.168.1.x (x is from
2 to 253), subnet mask, and default gateway
2) Select Use the following DNS server addresses, as shown in the following figure. And
then type the DNS server IP address, which should be provided by your ISP. Finally remember
to click OK to save settings.
Note: In most cases, type your local area DNS server IP addresses into it.
The Preferred DNS server is same to default gateway. For Secondary DNS server, you could
leave it blank or type in
Step 5
Click OK to save and apply your settings.
For Windows Vista & Windows 7
Step 1
Click on windows key+ R key on the keyboard at the same time.
Step 2
Type ncpa.cpl in the box, then press OK.
Step 3
Select the local area connection, right click it and select Properties.
Step 4
Select Internet Protocol Version 4(TCP/IPv4), double click it or click Properties.
Step 5
There are two ways to configure the TCP/IP Properties, Assigned by DHCP server
automatically or manually.
1. Assigned by DHCP server
Select Obtain an IP address automatically and Obtain DNS server address automatically. If
necessary, then click OK to save the settings.
2. Assigned manually
1) Select Use the following IP address, type IP address, subnet mask and default gateway IP
address into it.
If the router’s LAN IP address is, please type in IP address 192.168.1.x (x is from
2 to 253), subnet mask, and default gateway
2) Select Use the following DNS server addresses, as shown in the following figure. And
then type the DNS server IP address, which should be provided by your ISP. If necessary, then
click OK to save the settings.
Note: In most cases, type your local area DNS server IP addresses into it.
The Preferred DNS server is same to default gateway. For Secondary DNS server, you could
leave it blank or type in
Step 6
Click OK to save and apply your settings.
Configuration of TCP/IP protocols in Linux:This article covers the main TCP/IP network configuration files used by Linux to configure
various network services of the system such as IP Address, Default Gateway, Name servers DNS, hostname and much more. Any Linux Administrator must be well aware where these
services are configured and to use them. The good news is that most of the information provided
on this article apply's to Red hat Fedora, Enterprise Linux, Ubunto and other similar Linux
On most Linux systems, you can access the TCP/IP connection details within 'X Windows' from
Applications > Others > Network Connections. The same may also be reached through
Application > System Settings > Network > Configure. This opens up a window, which offers
configuration of IP parameters for wired, wireless, mobile broadband, VPN and DSL
The Basic Commands for Networking
The basic commands used in Linux are common to every distro:
ifconfig - Configures and displays the IP parameters of a network interface
route - Used to set static routes and view the routing table
hostname - Necessary for viewing and setting the hostname of the system
netstat - Flexible command for viewing information about network statistics, current
connections, listening ports
arp - Shows and manages the arp table
ip - Multi-purpose command for viewing and setting TCP/IP parameters and routes.
tc - Traffic control command, used for classifying, prioritizing, sharing, and limiting both
inbound and outbound traffic.
Experiment No 7.
AIM:-Implementation of file and printer sharing
Instructions for Installing “File and Printer Sharing” in Windows XP
From the desktop on your PC, go to the Start Menu and right click on My Network Places and select
(If you do not have this screen, go to the Control Panel and selected Network Connection.)
You should have a screen similar to the following:
Select Local Area Connection and right click and select Properties.
In the next diagram File and Printer Sharing for Microsoft Networks has already been installed, on your
screen it should not be listed, if it is, it is already installed. Now hit the Install button.
Now select Service form the list of component types and hit OK.
On the next screen select File and Printer Sharing for Microsoft Networks and hit OK.
File and Printer Sharing for Microsoft Networks should now be added to the list. Hit Close to exit.
Reboot your computer.
Experiment No 8.
AIM:-Designing and implementing Class A, B, and C Networks.
IP Address Classes:• IP addressing supports five different address classes: A, B, C, D and E. Only classes A, B and
C are available for commercial use.
Class A addresses
1. Class A addresses are designed for large organizations with a large number of hosts or routers.
2. In this the first octet of the address identifies the network and the next three octets are used to
identify the host.
3. The first bit of first octet is always 0 and the remaining 7 bits are used to identify the network
4. The next three octets i.e. 24 bits are used to identify the host.
5. The class support addresses from to
6. The first block of network address starts with and the last block of network address
starts with
7. As there are 7 bits in network address, 27 = 128 blocks of network address are possible. Out of
these two network blocks are reserved. Hence total 126 address blocks are used.
8. Each network blocks can have 224--- 2 hosts i.e. 16,777,214 host address. Two addresses are
less as one address is reserved for the broadcast address and one address is reserved for the
9. A block in class A is too large for almost any organization. This means most of the addresses
in class A are wasted and are not used.
Class B address
1. The class B addresses are designed for medium sized organizations with tens of thousands of
attached hosts or routers.
2. In this, the first two octets of the address identify the network and the next two octets identify
the host within the network.
3. The first two bits (high order bits) of first octet are always 1, 0. Thus the remaining 14 bits
identify the network
4. The third and fourth octet i.e. 6 bits are used to identify the host.
5. The first network block of this class covers the addresses from to (net
id 128.0). The last network block of this class covers addresses from (net id
6. The maximum number of network blocks in class B is 2 14 = 16384.
7 Each network block in class B can have 216--- 2 = 65,534 hosts.
8. A block in class B is also very large and most of the address in class B is also wasted.
Class C address
1. The class C addresses is designed for small organizations with a small number of attached
hosts or routers.
2. In class C, the first three octets of address are used for network and the last octet is used to
identify the host.
3. The first three bits of first octet are always set to 1, 1, 0.
4. The remaining 24 - 3 = 21 bits are used for network identification and only 8 bits are used for
5. In class C, 221 = 2,097,152 network blocks are possible.
6. Thus, each block in class C address can have 28 - 2 = 254 hosts.
7. The first block of network covers addresses from to
The last block of network covers the addresses form to
8. The class C addresses are too less for many organizations as it supports only 254 hosts in a
Following are the classes of IP:-
Class A
Class B to
Class C to
Class D to
Class E to
Class D address
1. Class D addresses are used for multicast groups (multicasting)
2. The concept of division of octets into network id and host id does not apply to class D.
3. The first four bits of first octet in class D are always set to 1,1,1,0.
4. The address range is to
Class E address
1. The Class E address is reserved for future use and is experimental.
2. The concept of network id and host id does not apply on class E also.
3. The first four bits of first octet are always set to 1,1,1,1.
4. The address range for class E is to
Experiment No 9.
AIM:-Subnet planning and its implementation.
SubNetting - What is Subnetting?
The process of subnetting involves dividing a network up into smaller networks called subnets or
sub networks. Each of these subnets has its own specific address. To create these additional
networks we use a subnet mask. The subnet mask simply determines which portion of the IP
address belongs to the host. The subnet address is created by dividing the host address into
network address and host address.
The network address specifies the type of subnetwork in the network and the host address
specifies the host of that subnet. Subnets are under local administration. As such, the outside
world sees an organization as a single network and has no detailed knowledge of the
organization's intema1 structure. Subnetting provides the network administrator with several
benefits, including extra flexibility, more efficient use of network address and the capability to
contain broadcast traffic. A given .network address can be broken up into may subnetworks. For
example,,, and are all subnets within network
A subnet address is created by. Borrowing bits from the host field and designating them as
subnet field. The number of bits borrowed varies and is specified by the subnet mask. Fig. shows
how bits are borrowed from the host address field to create the subnet address field.
The subnet mask does not alter the class of the IP address; it simply "borrows" bits from the host
portion and uses these to create subnets. This naturally reduces the maximum number of hosts
your network can have, because you are using some of your host bits for your subnet bits.
Experiment No 10.
AIM:-Installation of ftp server and client.
First, you should start by retrieving your Windows XP CD.
Next, click the Start button and go to the Control Panel.
After that, select "Add/Remove Windows Components."
Select "Internet Information Services" under "Windows Components."
Click "details" and select the "File Transfer Protocol (FTP)" service.
(Remember that this will also automatically select "Common Files" and "Internet
Information Services Snap-In.")
Click OK and follow the instructions for the install Wizard (or you can just
push next if you don't feel like reading). Be prepared with your Windows XP CD,
because it might prompt you for it if you haven't already installed it. Once it is done, you
might have to restart your computer after this.
After that, all you need to do is just paste the files you want to be public into
"C:\INETPUB\FTPROOT." Note that by default, these files are read-only and public.
Public meaning that anyone who knows the IP addresses may download copies from it.
8. There's more to go! Now, you need to configure your router's firewall to let FTP
traffic through. This can be done through your router's administration menu. Note that
this will vary depending on your router.
9. After letting your router firewall let FTP connections in, you will have to
configure your regular firewall to let FTP connections in through a certain port.
10. Finally, after done with everything, you may access your FTP site through
your browser. All you need to do is type in the URL where
"" is the WAN address of your computer.
Experiment No 11:AIM:-Difference between Internet & Intranet.
Difference between Internet and Intranet:Internet
Internet is a world-wide/global system of interconnected computer networks.
Internet uses the standard Internet Protocol (TCP/IP)
Every computer in internet is identified by a unique IP address.
IP Address is a unique set of numbers (such as which identifies a
computer location.
A special computer DNS (Domain Name Server) is used to give name to the IP Address
so that user can locate a computer by a name.
For example, a DNS server will resolve a name to a
particular IP address to uniquely identify the computer on which this website is hosted.
Internet is accessible to every user all over the world.
Intranet is system in which multiple PCs are networked to be connected to each other.
PCs in intranet are not available to the world outside of the intranet.
Usually each company or organization has their own Intranet network and
members/employees of that company can access the computers in their intranet.
Each computer in Intranet is also identified by a IP Address, which is unique among the
computers in that Intranet.
Similarities in Internet & Intranet
Intranet uses the internet protocols such as TCP/IP and FTP.
Intranet sites are accessible via web browser in similar way as websites in internet. But
only members of Intranet network can access intranet hosted sites.
In Intranet, own instant messengers can be used as similar to yahoo messenger/gtalk over
the internet.
Differences in Internet & Intranet
Internet is general to PCs all over the world where Intranet is specific to few PCs.
Internet is wider access and provides a better access to websites to large population
whereas Intranet is restricted.
Internet is not as safe as Intranet as Intranet can be safely privatized as per the need.
Experiment No 12:AIM: - Study of Client Server Architecture.
Client Server Architecture
Client/Server Architecture The client/server architecture significantly decreased network
traffic by providing a query response rather than total file transfer. It allows multi-user updating
through a GUI front end to a shared database. Remote Procedure Calls (RPCs) or standard query
language (SQL) statements are typically used to communicate between the client and server.
The following are the examples of client/server architectures.
1) Two tier architectures A two-tier architecture is where a client talks directly to a server, with
no intervening server. It is typically used in small environments(less than 50 users).
In two tier client/server architectures, the user interface is placed at user's desktop environment
and the database management system services are usually in a server that is a more powerful
machine that provides services to the many clients. Information processing is split between the
user system interface environment and the database management server environment.
2) Three tier architectures The three tier architecture is introduced to overcome the drawbacks
of the two tier architecture. In the three tier architecture, a middleware is used between the user
system interface client environment and the database management server environment.
These middleware are implemented in a variety of ways such as transaction processing monitors,
message servers or application servers. The middleware perform the function of queuing,
application execution and database staging. In addition the middleware adds scheduling and
prioritization for work in progress.
The three tier client/server architecture is used to improve performance for large number of users
and also improves flexibility when compared to the two tier approach.
The drawback of three tier architectures is that the development environment is more difficult to
use than the development of two tier applications.
The widespread use of the term 3-tier architecture also denotes the following architectures:
• Application sharing between a client, middleware and enterprise server
• Application sharing between a client, application server and enterprise database server.
i) Three tier with message server. In this architecture, messages are processed and prioritized
asynchronously. Messages have headers that include priority information, address and
identification number. The message server links to the relational DBMS and other data sources.
Messaging systems are alternative for wireless infrastructures.
ii) Three tier with an application server this architecture allows the main body of an
application to run on a shared host rather than in the user system interface client environment.
The application server shares business logic, computations and a data retrieval engine. In this
architecture applications are more scalable and installation costs are less on a single server than
maintaining each on a desktop client.
3-tier architecture provides
• A greater degree of flexibility
• Increased performance, as tasks are shared between servers
The basic characteristics of client/server architectures are:
1) Combination of a client or front-end portion that interacts with the user, and a server or
back-end portion that interacts with the shared resource. The client process contains solutionspecific logic and provides the interface between the user and the rest of the application system.
The server process acts as a software engine that manages shared resources such as databases,
printers, modems, or high powered processors.
2) The front-end task and back-end task have fundamentally different requirements for
computing resources such as processor speeds, memory, disk speeds and capacities, and
input/output devices.
3) The environment is typically heterogeneous and multivendor. The hardware platform and
operating system of client and server are not usually the same. Client and server processes
communicate through a well-defined set of standard application program interfaces (API's) and
4) An important characteristic of client-server systems is scalability. They can be scaled
horizontally or vertically. Horizontal scaling means adding or removing client workstations with
only a slight performance impact. Vertical scaling means migrating to a larger and faster server
machine or multi servers.
Block Diagram of Client Server Architecture.
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