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PRACTICAL NO:1
SPECIFICATION OF LATEST DESKTOPS AND LAPTOPS:
What do you understand by specifications?
Before buying a computer desktop or laptop one must keep in mind certain things that must be
present within the system. These things or parameters are refered to as specifications of a
computer system.
These parameters are:







Operating System
Software Suite
Virus and Spyware protection
Computer hardware
Ethernet cable
NIC/Ethernet Card
Insurance
WHAT IS A DESKTOP?
A desktop computer is a personal computer (PC) in a form intended for regular use at a single
location, as opposed to a mobile laptop or portable computer. Early desktop computers are
designed to lie flat on the desk, while modern towers stand upright. Most modern desktop
computers have separate screens and keyboards.
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Motherboard:
A motherboard (sometimes alternatively known as the mainboard, system board, planar board or logic
board,or colloquially, a mobo) is the main printed circuit board (PCB) found in computers and other
expandable systems. It holds many of the crucial electronic components of the system, such as the
central processing unit (CPU) and memory, and provides connectors for other peripherals. Unlike a
backplane, a motherboard contains significant sub-systems such as the processor and other
components.
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Video Card:
A video card (also called a video adapter, display card, graphics card, graphics board, display adapter
or graphics adapter and sometimes preceded by the word discrete or dedicated to emphasize the
distinction between this implementation and integrated graphics) is an expansion card which generates
a feed of output images to a display (such as a computer monitor). Within the industry, video cards are
sometimes called graphics add-in-boards, abbreviated as AIBs,[1] with the word "graphics" usually
omitted. Virtually all current video cards are built with either AMD-sourced or Nvidia-sourced graphics
chips.[1] Most video cards offer various functions such as accelerated rendering of 3D scenes and 2D
graphics, MPEG-2/MPEG-4 decoding, TV output, or the ability to connect multiple monitors (multimonitor).
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RAM:
Random-access memory (RAM /ræm/) is a form of computer data storage. A random-access device
allows stored data to be accessed directly in any random order. In contrast, other data storage media
such as hard disks, CDs, DVDs and magnetic tape, as well as early primary memory types such as drum
memory, read and write data only in a predetermined order, consecutively, because of mechanical
design limitations. Therefore, the time to access a given data location varies significantly depending on
its physical location.
Today, random-access memory takes the form of integrated circuits. Strictly speaking, modern types of
DRAM are not random access, as data is read in bursts, although the name DRAM / RAM has stuck.
However, many types of SRAM, ROM, OTP, and NOR flash are still random access even in a strict sense.
RAM is normally associated with volatile types of memory (such as DRAM memory modules), where its
stored information is lost if the power is removed.
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Processor
The microprocessor is a multipurpose, programmable device that accepts digital data as input,
processes it according to instructions stored in its memory, and provides results as output. It is an
example of sequential digital logic, as it has internal memory. While 64-bit microprocessor
designs have been in use in several markets since the early 1990s (including the Nintendo 64
gaming console in 1996), the early 2000s saw the introduction of 64-bit microprocessors targeted
at the PC market.
Nowadays, multi-core processors are used in computer systems. A multi-core processor is simply
a single chip that contains more than one microprocessor core. This effectively multiplies the
processor's potential performance by the number of cores (as long as the operating system and
software is designed to take advantage of more than one processor core). Some components,
such as bus interface and cache, may be shared between cores. Because the cores are physically
very close to each other, they can communicate with each other much faster than separate
processors in a multiprocessor system, which improves overall system performance.
In the processors markets, Intel and AMD have been arch-rivals since a long time. While Intel
focuses on performance and compatibility, AMD focuses more on price and overall performance.
For example, Intel's cheapest Sandy Bridge quad-core CPUs often cost almost twice as much as
AMD's cheapest Athlon II, Phenom II, and FX quad-core CPUs but Intel has dual-core CPUs in
the same price ranges as AMD's cheaper quad core CPUs. In an application that uses one or two
threads, the Intel dual cores outperform AMD's similarly priced quad-core CPUs—and if a
program supports three or four threads the cheap AMD quad-core CPUs outperform the similarly
priced Intel dual-core CPUs.
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SPECIFICATIONS OF DESKTOP:

ACER ASPIRE AME600 UR378:
Type:
Processor Family:
RAM:
Storage Capacity:
Graphics Card:
Primary Optical Drive:
Operating System:
Price:

Gaming
Intel Core i7
8GB
1750GB
nVidia GeForce GT 545M
BD/DVD/CD +/-RW
Microsoft Windows 7
$981.79
GATEWAY DX4870 UR11P:
Type:
Processor:
RAM:
Storage Capacity:
Graphics Card:
Primary Optical Drive:
Operating System:
Price:

2000
ASUS ESSENTIO CM6870:
Type:
Processor Family:
RAM:
Storage Capacity:
Graphics Card:
Primary Optical Drive:
Operating System:
Price:

Mainstream, Multimedia
Intel Core i7
10 GB
2000 GB
Intel HD Graphics 4000
Dual-Layer DVD+/-RW
Microsoft Windows 8
$719.86
Mainstream
Intel Core i7
10 GB
200 GB
Intel HD Graphics
DVD+RW (Plus)
Microsoft Windows 7
$879.00
DELL VOSTRO 470:
Type:
Processor:
RAM:
Storage Capacity:
Graphics Card:
Primary Optical Drive:
Operating System:
Price:
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Intel Core i7
8 GB
1000 GB
AMD Radeon HD 7570M
DVD+/-RW
Microsoft Windows 7
$649.00
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
HP PAVILION P7 1380T:
Type:
Processor:
RAM:
Storage Capacity:
Graphics Card:
Primary Optical Drive:
Operating System:
Price:
Multimedia
Intel Core i5 3330
6 GB
1TB
Integrated Intel HD Graphics
Super multi DVD burner
Microsoft Windows 7
Rs.30975.00
WHAT IS A LAPTOP?
A laptop computer is a personal computer for mobile use.[1] A laptop has most of the same
components as a desktop computer, including a display, a keyboard, a pointing device such as
a touchpad (also known as a trackpad) and/or a pointing stick, and speakers into a single unit.
A laptop is powered by mains electricity via an AC adapter, and can be used away from an
outlet using a rechargeable battery. Laptops are also sometimes called notebook
computers, notebooks, ultrabook or netbook.
SPECIFICATIONS OF LAPTOPS:

HP ENVY d6t
Processor:
Video Card:
Audio:
Operating System:
Memory(RAM):
Hard Drive Storage:
Screen Resolution:

APPLE MACBOOK PRO
Processor:
Video Card:
Audio:
Operating System:
Memory(RAM):
Hard Drive Storage:
Screen Resolution:

Intel Core i7
Ge Force GT 650M
Beats Audio
Windows 8 Home Premium
8 GB
750 GB
1366 x 768080
Intel Core i7
AMD Radeon HD 6770M
Integrated d Stereo
Mac OS X v10. 7 Lion
4 GB
750 GB
1920 x 1200
DELL XPS 15z
Processor:
Video Card:
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Intel Core i5 2430M
NVIDIA Ge Force GT 525M
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Audio:
Operating System:
Memory(RAM):
Hard Drive Storage:
Screen Resolution:

APPLE MACBOOK AIR
Processor:
Video Card:
Audio:
Operating System:
Memory(RAM):
Hard Drive Storage:
Screen Resolution:

Wavws MaxxAudi 0.3
Windows 7 Home Premium 64
6 GB
500 GB
1280 x 720
Intel Core i5-560UM
Intel HD Graphics 4000
Integrated d Stereo
Mac OS X v10. 7 Lion
4 GB
128 GB
1366 x 768
SONY VAIO S SERIES
Processor:
Video Card:
Audio:
Operating System:
Memory(RAM):
Hard Drive Storage:
Screen Resolution:
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Intel Core i5-2450M
NVIDIA Ge Force GT 640M LE
Integrated d
Windows 7 Home Premium
6 GB
640 Gb
1600 x 900
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PRACTICAL NO:2
FAMILARIZATION WITH NETWORKING COMPONENTS AND DEVICES
NETWORKING COMPONENTS/DEVICES:Networking hardware or networking equipment typically refers to devices facilitating the use
of a computer network. Typically, this includes gateways, routers, network bridges, switches,
hubs, and repeaters. Also, hybrid network devices such as multilayer switches, protocol
converters, bridge routers, proxy servers, firewalls, network address translators, multiplexers,
network interface controllers, wireless network interface controllers, modems, ISDN terminal
adapters, line drivers, wireless access points, networking cables and other related hardware.
Computer networking devices are units that mediate data in a computer network. Computer
networking devices are also called network equipment, Intermediate Systems (IS) or
Interworking Unit (IWU). Units which are the last receiver or generate data are called hosts or
data terminal equipment.
VARIOUS NETWORKING DEVICES : SWITCHES:- A network switch is a computer networking device that links network
segments or network devices. The term commonly refers to a multi-port network bridge
that processes and routes data at the data link layer of the OSI model. Switches that
additionally process data at the network layer and above are often called or multilayer
switches.Switches exist for various types of networks including Fibre Channel,
Asynchronous Transfer Mode, Infini Band, Ethernet and others.
USES:- A switch is a telecommunication device which receives a message from any
device connected to it and then transmits the message only to the device for which the
message was meant. This makes the switch a more intelligent device than a hub (which
receives a message and then transmits it to all the other devices on its network). The
network switch plays an integral part in most modern Ethernet local area networks
(LANs). Mid-to-large sized LANs contain a number of linked managed switches.
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Fig2.1 Representing a switch
 HUB:- It is a device for connecting multiple Ethernet devices together and making
them act as a single network segment. It has multiple input/output (I/O) ports, in which
a signal introduced at the input of any port appears at the output of every port except
the original incoming. A hub works at the physical layer of the OSI model. The
device is a form of multiport repeater. Repeater hubs also participate in collision
detection, forwarding a jam signal to all ports if it detects a collision.
USES OF HUB:-


For inserting a protocol analyzer into a network connection, a hub is an alternative to a
network tap or port mirroring.
When a switch is accessible for end users to make connections, for example, in a
conference room, an inexperienced or careless user can bring down the network by
connecting two ports together, causing a switching loop. This can be prevented by using a
hub, where a loop will break other users on the hub, but not the rest of the network.

Fig2.2 Representing a hub
ROUTER:- It is a device that forwards data packets between computer networks,
creating an overlay internetwork. A router is connected to two or more data lines from
different networks. When a data packet comes in one of the lines, the router reads the
address information in the packet to determine its ultimate destination. Then, using
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information in its routing table or routing policy, it directs the packet to the next
network on its journey. Routers perform the "traffic directing" functions on the
Internet. A data packet is typically forwarded from one router to another through the
networks that constitute the internetwork until it gets to its destination node.
USES OF ROUTER:

Routers may provide connectivity within enterprises, between enterprises and the
Internet, and between internet service providers (ISPs) networks. The largest routers
(such as the Cisco CRS-1 or Juniper T1600) interconnect the various ISPs, or may be
used in large enterprise networks.
Routers may also be used to connect two or more logical groups of computer devices
known as subnets, each with a different sub-network address. The subnets addresses
recorded in the router do not necessarily map directly to the physical interface
connections.[2] A router has two stages of operation called planes:[
Fig2.3 Repesenting a router.
 LAN ADAPTER:- It is a device used to allow a computer to interface with a
network. Many computers may have some sort of LAN adapter already installed, but
others may require a special installation, which is accomplished by adding a network
interface card to the system or possibly connecting the adapter to a USB port.
USES OF LAN ADAPTER:

Most networks that are used in an office or home environment are known as local area
networks (LANs). This type of network is one used over a limited geographic area. Most
of the time, the network goes no further than the building which houses its main
components, though that is not always the case. A LAN adapter is simply one that is able
to access this type of network.
A LAN adapter can be used with a wireless or wired network, though when purchasing
on, it is important to understand what type of network and connection is needed. In most
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cases, a wireless LAN adapter cannot be used for a wired network and vice versa. Those
needing an adapter but unsure of the type should consult their network administrators for
more information.
Fig2.4 Representing LAN adapter
Other hardware for establishing networks or dial-up connections:
 NETWORK INTERFACE CONTROLLER:- (also known as a network interface
card, network adapter, LAN adapter and by similar terms) is a computer hardware
component that connects a computer to a computer network.


Early network interface controllers were commonly implemented on expansion cards that
plugged into a computer bus; the low cost and ubiquity of the Ethernet standard means
that most newer computers have a network interface built into the motherboard.
The network controller implements the electronic circuitry required to communicate
using a specific physical layer and data link layer standard such as Ethernet, Wi-Fi or
Token Ring. This provides a base for a full network protocol stack, allowing
communication among small groups of computers on the same LAN and large-scale
network communications through routable protocols, such as IP.
Fig2.7 Representing NIC
 MODEM (modulator-demodulator):- It is a device that modulates an analog carrier
signal to encode digital information, and also demodulates such a carrier signal to
decode the transmitted information. The goal is to produce a signal that can be
transmitted easily and decoded to reproduce the original digital data. Modems can be
used over any means of transmitting analog signals, from light emitting diodes to
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radio. The most familiar example is a voice band modem that turns the digital data of
a personal computer into modulated electrical signals in the voice frequency range of
a telephone channel. These signals can be transmitted over telephone lines and
demodulated by another modem at the receiver side to recover the digital data.
Representing a modem
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PRACTICAL NO:3
Familiarization with Transmission media and tools: Co-axial cable, UTP cable, Crimping
tools, Connectors etc.
Transmission media:The means through which data is transformed from one place to another is called transmission or
communication media. Transmission media is a pathway through which data are transmitted in
communication networks. So, a transmission medium can be defined as anything that can carry
information from a source to destination. For example, the transmission medium for sound
received by the ears is usually air, but solids and liquids may also act as transmission media for
sound. There are two categories of transmission media used in computer communications.

BOUNDED/GUIDED MEDIA

UNBOUNDED/UNGUIDED MEDIA
GUIDED MEDIA:Guided media, which are those that provide a conduit from one device to another, include
twisted-pair cable, coaxial cable, and fiber-optic cable.Guided Transmission Media uses a
"cabling" system that guides the data signals along a specific path. The data signals are bound by
the "cabling" system. Guided Media is also known as Bound Media. Cabling is meant in a
generic sense in the previous sentences and is not meant to be interpreted as copper wire cabling
only. Cable is the medium through which information usually moves from one network device to
another.
Twisted pair cable and coaxial cable use metallic (copper) conductors that accept and transport
signals in the form of electric current. Optical fiber is a glass or plastic cable that accepts and
transports signals in the form of light. Three common types of bounded media are used of the
data transmission. These are

Coaxial Cable

Twisted Pairs Cable

Fiber Optics Cable
COAXIAL CABLE:
Coaxial cable is very common & widely used commutation media. For example TV wire is
usually coaxial. Coaxial cable gets its name because it contains two conductors that are parallel
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to each other. The center conductor in the cable is usually copper. The copper can be either a
solid wire or stranded martial.
Fig 3.1: Coaxial cable
Gauge is the measure of the cable thickness. It is measured by the Radio grade measurement, or
RG number. The high the RG number, the thinner the central conductor core, the lower the
number the thicker the core.
Here the most common coaxial standards.




50-Ohm RG-7 or RG-11 : used with thick Ethernet.
50-Ohm RG-58 : used with thin Ethernet
75-Ohm RG-59 : used with cable television
93-Ohm RG-62 : used with ARCNET.
 Characteristics of Coaxial cable:

Low cost

Easy to install

Up to 10Mbps capacity

Medium immunity form EMI

Medium of attenuation
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 Advantages Coaxial cable:

Inexpensive

Easy to wire

Easy to expand

Moderate level of EMI immunity
 Disadvantage Coaxial cable:

Single cable failure can take down an entire network.
TWISTED PAIR CABLE:
The most popular network cabling is Twisted pair. It is light weight, easy to install, inexpensive
and support many different types of network. It also supports the speed of 100 mps. Twisted pair
cabling is made of pairs of solid or stranded copper twisted along each other. The twists are done
to reduce vulnerably to EMI and cross talk. The number of pairs in the cable depends on the
type. The copper core is usually 22-AWG or 24-AWG.
Fig 3.2: Twisted pair cable
There are two types of twisted pairs cabling:
1. Unshielded twisted pair (UTP)
2. Shielded twisted pair (STP)
1. Unshielded twisted pair (UTP):UTP is more common. It can be either voice grade or data grade depending on the condition.
UTP cable normally has an impedance of 100 ohm. UTP cost less than STP and easily available
due to its many use. These are used in telephone lines and low speed data cable. These cable supports up to
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16 mps and are mostly used in 10 mps. UTP cables consist of 2 or 4 pairs of twisted cable. Cable with 2 pair
use RJ-11 connector and 4 pair cable use RJ-45 connector. Tighter the twisting, the higher is the supported
transmission rate and greater the cost per foot.
Fig 3.3: Unshielded twisted pair cable
Fig 3.3.1 : Categories
Characteristics of UTP:

low cost

easy to install

High speed capacity

High attenuation
Advantages of UTP:

Easy installation

Capable of high speed for LAN

Low cost
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Disadvantages of UTP:

Short distance due to attenuation
2. Shielded twisted pair (STP)
Shielded twisted pair cable has a mesh shielding that’s protects it from EMI which allows for higher
transmission rate. STP features two pairs of 22-AWG. This type include type 1 with 4 telephone pairs. This
type of STP consist of 1 pair of standard shielded 26-AWG.
Fig 3.4: Shielded Twisted pair
Characteristics of STP:

Medium cost

Easy to install

Higher capacity than UTP

Higher attenuation, but same as UTP

Medium immunity from EMI

100 meter limit
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Advantages of STP:

Shielded

Faster than UTP and coaxial
Disadvantages of STP:

More expensive than UTP and coaxial

More difficult installation

High attenuation rate
FIBER OPTICS
Fiber optic cable uses electrical signals to transmit data. It uses light. In fiber optic cable light
only moves in one direction for two way communication to take place a second connection must
be made between the two devices. It is actually two stands of cable. Each stand is responsible for
one direction of communication. A laser at one device sends pulse of light through this cable to
other device. These pulses translated into “1’s” and “0’s” at the other end.In the center of fiber
cable is a glass stand or core. The light from the laser moves through this glass to the other
device around the internal core is a reflective material known as CLADDING.
Fig 3.5: Fiber optical cable
Characteristics Of Fiber Optic Cable:

Expensive

Very hard to install

Capable of extremely high speed

Extremely low attenuation
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
No EMI interference
Advantages Of Fiber Optic Cable:

Fast

Low attenuation

No EMI interference
Disadvantages Fiber Optics:

Very costly

Hard to install
UNGUIDED MEDIA
Unguided media or wireless media doesn't use any physical connectors between the two
devices communicating. Usually the transmission is send through the atmosphere but sometime
it can be just across the rule. Wireless media is used when a physical obstruction or distance
blocks are used with normal cable media. The three types of wireless media are:

Radio waves

Micro waves

Infrared waves
RADIO WAVES:
Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic
spectrum longer than infrared light. Radio waves have frequencies from 300 GHz to as low as
3 kHz, and corresponding wavelengths from 1 millimeter to 100 kilometers. Like all other
electromagnetic waves, they travel at the speed of light. Naturally occurring radio waves are
made by lightning, or by astronomical objects. Artificially generated radio waves are used for
fixed
and
mobile radio
communication, broadcasting, radar and
other
navigation
systems, communications satellites, computer networks and innumerable other applications.
Different frequencies of radio waves have different propagation characteristics in the Earth's
atmosphere; long waves may cover a part of the Earth very consistently, shorter waves can
reflect off the ionosphere and travel around the world, and much shorter wavelengths bend or
reflect very little and travel on a line of sight.
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Fig 3.6: RADIO WAVES:
MICRO WAVES
Microwaves are radio waves with wavelengths ranging from as long as one meter to as short as
one millimeter, or equivalently, with frequencies between 300 MHz (0.3 GHz) and
300 GHz. This broad definition includes both UHF and EHF (millimeter waves), and various
sources use different boundaries. In all cases, microwave includes the entire SHF band (3 to
30 GHz, or 10 to 1 cm) at minimum, with RF engineering often putting the lower boundary at
1 GHz (30 cm), and the upper around 100 GHz (3 mm).
Fig 3.7 : MICRO WAVES
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INFRARED
Infrared technology allows computing devices to communicate via short-range wireless signals.
With infrared, computers can transfer files and other digital data bidirectionally. The infrared
transmission technology used in computers is similar to that used in consumer product remote
control units. Infrared communications span very short distances. Place two infrared devices
within a few feet (no more than 5 meters) of each other when networking them. Unlike WiFi and Bluetooth technologies, infrared network signals cannot penetrate walls or other
obstructions and work only in the direct "line of sight."
Fig 3.7 : INFRARED
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 RJ45 and RJ-11 connectors to the end of the cable. In the picture to the right, is an example of what
a crimping tool looks like. This example shows a tool capable of crimping both RJ-11 and RJ-45
connectors.
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Fig 3.8: Crimping tool
CONNECTORS
The world of connectors has a much smaller world of acronyms all its own. They consist of such
acronyms as RJ, SMA, ST, TNC, BNC, V.32, DIN, DB, N and more. One aspect that might
complicate the world of connectors is that many of these connectors are also known by more
than one name. Most of us know that a connector is best known for providing the physical link
between two components. Some example of the use of a connector might be a connector linking
a cable and a network interface card or NIC card, a connector linking a transceiver and a cable or
even a connector linking two cable segments.
Optical fiber connector: - Optical fiber connectors are used to join optical fibers where a
connect/disconnect capability is required. The basic connector unit is a connector assembly. A
connector assembly consists of an adapter and two connector plugs.
Fig 3.8: Optical fiber connector
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Registered jack:A registered jack (RJ) is a standardized physical network interface — both jack construction and
wiring pattern — for connecting telecommunications or data equipment to a service provided by
a local exchange carrier or long distance carrier. The standard designs for these connectors and
their wiring are named RJ11, RJ14, RJ21, RJ45, RJ48, etc. Many of these interface standards are
commonly used in North America, though some interfaces are used world-wide.
The physical connectors that registered jacks use are mainly of the modular connector and 50-pin
miniature ribbon connector types. For example, RJ11 uses a 6 position 2 conductor (6P2C)
modular plug and jack, while RJ21 uses a 50-pin miniature ribbon connector.
Fig 3.9: RJ 45 Connectors
RF connector:A coaxial RF connector is an electrical connector designed to work at radio frequencies in the
multi-megahertz range. RF connectors are typically used with coaxial cables and are designed to
maintain the shielding that the coaxial design offers. Better models also minimize the change in
transmission line impedance at the connection. Mechanically, they provide a fastening
mechanism (thread, bayonet, braces, push pull) and springs for a low ohmic electric contact
while sparing the gold surface, thus allowing above 1000 reconnects and reducing the insertion
force. Research activity in the area of radio-frequency (RF) circuit design has surged in the
2000s in direct response to the enormous market demand for inexpensive, high-data-rate wireless
transceivers.
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Fig 3.10: RF connector Connectors
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PRACTICAL NO:4
TO PREPARE STRAIGHT AND CROSS CABLES
Straight cable: Straight-Cable 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-Cable 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).
Making Straight Cable:
Requirements: Two RJ45 Connectors, Crimping tool & CAT 5 cable of desired
length(less than 250 meters).
Nomenclature: Brown (8), Brown White (7),
Green (6), Green White (3), Blue (4), Blue White (5),
Orange (2), Orange White (1)
Steps:
1. Remove the covering of CAT 5 cable.
2. Straighten the eight wires of the cable.
3. Using Crimping tool’s cutter cut the end of wires so that they are of same length
4. Arrange the wire in order 1, 2, 3, 4, 5, 6, 7 & 8 respectively as I have mention or as shown in
the diagram.
5. Insert the arranged cable in the RJ45 connector with clip pointing down exactly as shown in
the figure.
6. In crimping tool insert the head of RJ45 connector and crimp (press) it hardly.
7. Follow same step with same color order for the other end of cable too.
8. The wire you made by following these steps is a STRAIGHT cable.
Fig.4.1: Straight cable
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Fig.4.2: Reference Diagram(Straight Cable)
Making Cross Cable:
Of the Eight wires in Cat 5 not all are used for data transfer when using 100Mbps Ethernet card.
Only 2 pairs of cable are used i.e. 2 wire for transmitting signal and two wires for receiving
signal.
So now you can guess why we have to make CROSS CABLE for connecting same kind of
devices. Because if use same color coding on both the side than transmitter of one m/c will send
data to transmitter of another and data packets will lost, so we have to change wiring code so that
transmitter of one connects to reciver of other and vice-versa.
Reference diagram:
Fig.4.3: Refrence Diagram (Cross Cable)
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Steps:
Steps 1 to 6 are same as for STRAIGHT through cables
7. Only difference is in color coding of other side of wire.
8. Wire that is on 1st number on A-side (one end) should be on 3rd number on Bside (other side) & vice-versa.
9. Wire that is on 2st number on A-side (one end) should be on 6rd number on Bside (other side) & vice versa.
10. Now Crimp the RJ45 connector.
11. Your CROSS wire is completed.
Fig.4.3: Cross Cable
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PRACTICAL NO:5
Study of various LAN topologies and their creation using network devices, cables and
computers.
local area network (LAN) is a computer network covering a small physical area, like a home,
office, or small group of buildings, such as a school, or an airport. The defining characteristics of
LANs, in contrast to wide-area networks (WANs), include their usually higher data-transfer
rates, smaller geographic range, and lack of a need for leased telecommunication lines.
Components:-1.LAN Card: A network card, network adapter, network interface controller (NIC), network interface
card, or LAN adapter is a computer hardware component designed to allow computers to communicate
over a computer network. It is both an OSI layer 1 (physical layer) and layer 2 (data link layer) device, as
it provides physical access to a networking medium and provides a low-level addressing system through
the use of MAC addresses. It allows users to connect to each other either by using cables or wirelessly.
Although other network technologies exist, Ethernet has
achieved near-ubiquity since the mid-1990s. Every Ethernet
network card has a unique 48-bit serial number called a
MAC address, which is stored in ROM carried on the card.
Every computer on an Ethernet network must have a card
with a unique MAC address. Normally it is safe to assume
that no two network cards will share the same address,
because card vendors purchase blocks of addresses from the
Institute of Electrical and Electronics Engineers (IEEE) and
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assign a unique address to each card at the time of manufacture.
The card implements the electronic circuitry required to communicate using a specific physical
layer and data link layer standard such as Ethernet or token ring. This provides a base for a full
network protocol stack, allowing communication among small groups of computers on the same
LAN and large-scale network communications through routable protocols, such as IP.
There are four techniques used to transfer data, the NIC may use one or more of these
techniques.
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Polling is where the microprocessor examines the status of the peripheral under program
control.
Programmed I/O is where the microprocessor alerts the designated peripheral by applying
its address to the system's address bus.
Interrupt-driven I/O is where the peripheral alerts the microprocessor that it's ready to
transfer data.
DMA is where the intelligent peripheral assumes control of the system bus to access
memory directly. This removes load from the CPU but requires a separate processor on
the card.
A network card typically has a twisted pair, BNC, or AUI socket where the network cable is
connected, and a few LEDs to inform the user of whether the network is active, and whether or
not there is data being transmitted on it. Network Cards are typically available in 10/100/1000
Mbit/s varieties. This means they can support a transfer rate of 10, 100 or 1000 Megabits per
second.
2.Network Switch.
Network switch is a computer networking device that connects network segments. The term
commonly refers to a Network bridge that processes and routes data at the Data link layer (layer
2) of the OSI model. Switches that additionally process data at the Network layer (layer 3 and
above) are often referred to as Layer 3 switches or Multilayer
switches.
The term network switch does not generally encompass
unintelligent or passive network devices such as hubs and
repeaters. The first Ethernet switch was introduced by Kalpana
in 1990.
As with hubs, Ethernet implementations of network switches
support either 10/100 Mbit/s or 10/100/1000 Mbit/s ports
Ethernet standards. Large switches may have 10 Gbit/s ports.
Switches differ from hubs in that they can have ports of
different speed.
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The network switch, packet switch (or just switch) plays an integral part in most Ethernet local
area networks or LANs. Mid-to-large sized LANs contain a number of linked managed switches.
Small office, home office (SOHO) applications typically use a single switch, or an all-purpose
converged device such as gateway access to small office/home office broadband services such as
DSL router or cable, Wi-Fi router. In most of these cases, the end user device contains a router
and components that interface to the particular physical broadband technology, as in the Linksys
8-port and 48-port devices. User devices may also include a telephone interface to VoIP.
In the context of a standard 10/100 Ethernet switch, a switch operates at the data-link layer of the
OSI model to create a different collision domain per switch port. If you have 4 computers
A/B/C/D on 4 switch ports, then A and B can transfer data between them as well as C and D at
the same time, and they will never interfere with each others' conversations. In the case of a
"hub" then they would all have to share the bandwidth, run in half-duplex and there would be
collisions and retransmissions. Using a switch is called micro-segmentation. It allows you to
have dedicated bandwidth on point to point connections with every computer and to therefore
run in full duplex with no collisions.
Topologies:
1.Bus
In computer architecture, a bus is a subsystem that transfers data between computer components
inside a computer or between computers. Unlike a point-to-point connection, a bus can logically
connect several peripherals over the same set of wires. Each bus defines its set of connectors to
physically plug devices, cards or cables together.
Early computer buses were literally parallel electrical buses with multiple connections, but the
term is now used for any physical arrangement
that provides the same logical functionality as a
parallel electrical bus. Modern computer buses
can use both parallel and bit-serial connections,
and can be wired in either a multidrop (electrical
parallel) or daisy chain topology, or connected by
switched hubs, as in the case of USB.
In a network, the master scheduler controls the
data traffic. If data is to be transferred the requesting computer sends a message to the scheduler,
which puts the request into a queue. The message contains an identification code which is
broadcast to all nodes of the network. The scheduler works out priorities and notifies the receiver
as soon as the bus is available.
The identified node takes the message and performs the data transfer between the two computers.
Having completed the data transfer the bus becomes free for the next request in the scheduler's
queue.
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Bus benefit: any computer can be accessed directly and messages can be sent in a relatively
simple and fast way. Disadvantage: needs a scheduler to assign frequencies and priorities to
organize the traffic.
2.Ring
A ring network is a network topology in which each
node connects to exactly two other nodes, forming a
single continuous pathway for signals through each
node - a ring. Data travels from node to node, with each
node along the way handling every packet.
Because a ring topology provides only one pathway
between any two nodes, ring networks may be
disrupted by the failure of a single link. A node failure
or cable break might isolate every node attached to the
ring. FDDI networks overcome this vulnerability by
sending data on a clockwise and a counterclockwise ring: in the event of a break data is wrapped
back onto the complementary ring before it reaches the end of the cable, maintaining a path to
every node along the resulting "C-Ring". 802.5 networks -- also known as IBM Token Ring
networks -- avoid the weakness of a ring topology altogether: they actually use a star topology at
the physical layer and a Multistation Access Unit to imitate a ring at the datalink layer.
3. Star Topology
A star configuration is simple: Each of several devices has its own cable that connects to a
central hub, or sometimes a switch, multipoint repeater, or even a Multistation Access Unit
(MAU). Data passes through the hub to reach other devices on the network. Ethernet over
unshielded twisted pair (UTP), whether it is 10BaseT, 100BaseT, or Gigabit, all use a star
topology.
Star networks are one of the most common computer network topologies. In its simplest form, a
star network consists of one central switch, hub or computer which acts as a router to transmit
messages. If the central node is passive, the originating node must be able to tolerate the
reception of an echo of its own transmission, delayed by the two-way transmission time (i.e. to
and from the central node) plus any delay generated in the central node. An active star network
has an active central node that usually has the means to prevent echo-related problems.
The star topology reduces the chance of network failure by connecting all of the systems to a
central node. When applied to a bus-based network, this central hub rebroadcasts all
transmissions received from any peripheral node to all peripheral nodes on the network,
sometimes including the originating node. All peripheral nodes may thus communicate with all
others by transmitting to, and receiving from, the central node only. The failure of a transmission
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line linking any peripheral node to the central node will result in the isolation of that peripheral
node from all others, but the rest of the systems will be unaffected.
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You will find that a star topology is most common in networks. This is mainly because of the
ease of configuring and troubleshooting it. If a wire or a single port on the hub or switch goes
bad, only one network node goes down, which prevents a huge impact on productivity overall
(unless the entire hub or switch fails-in which case, the whole LAN goes down). However,
because a star topology involves a central hub or switch as well as a lot more cabling, it costs
more to implement.
Disadvantages of a Star Network
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Twisted pair cables typically used in star topologies are not as immune to interferences as
coxial cable
Expensive because of additional cabling and central hub require
If the centralize device fails the entire system is affected.
Advantages of Star Network
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Easy to Install: Each device on network simply requires a cable run between it and the
concentrator device.
Flexible: Devices can be added or removed without affecting the other devices on the
network.
A single device or cable failure will not bring down the network
Easy to set up and to expand.as each device on the network simply requires a cable run
between it and the concentrator device
Any non-centralised failure will have very little effect on the network, whereas on a ring
network it would all fail with one fault.
Data Packets are sent quickly as they do not have to travel through any unnecessary
nodes.
Performance is greater with speeds capable of 10mbps to 100mbps or more
The ability to isolate individual devices in troubleshooting An intelligent central hub or
switch that can help diagnose and manage the network Adjusting traffic levels so that
computers that place heavy loads on the network are moved to separate hubs
4. TREE Topology
The type of network topology in which a central 'root' node (the top level of the hierarchy) is
connected to one or more other nodes that are one level lower in the hierarchy (i.e., the second
level) with a point-to-point link between each of the second level nodes and the top level central
'root' node, while each of the second level nodes that are connected to the top level central 'root'
node will also have one or more other nodes that are one level lower in the hierarchy (i.e., the
third level) connected to it, also with a point-to-point link, the top level central 'root' node being
the only node that has no other node above it in the hierarchy - the hierarchy of the tree is
symmetrical, each node in the network having a specific fixed number, f, of nodes connected to
it at the next lower level in the hierarchy, the number, f, being referred to as the 'branching factor'
of the hierarchical tree.
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A network that is based upon the physical hierarchical topology must have at least three levels in
the hierarchy of the tree, since a network with a central 'root' node and only one hierarchical
level below it would exhibit the physical topology of a star.
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A network that is based upon the physical hierarchical topology and with a branching
factor of 1 would be classified as a physical linear topology.
The branching factor, f, is independent of the total number of nodes in the network and,
therefore, if the nodes in the network require ports for connection to other nodes the total
number of ports per node may be kept low even though the total number of nodes is large
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- this makes the effect of the cost of adding ports to each node totally dependent upon the
branching factor and may therefore be kept as low as required without any effect upon
the total number of nodes that are possible.
The total number of point-to-point links in a network that is based upon the physical
hierarchical topology will be one less that the total number of nodes in the network.
If the nodes in a network that is based upon the physical hierarchical topology are
required to perform any processing upon the data that is transmitted between nodes in the
network, the nodes that are at higher levels in the hierarchy will be required to perform
more processing operations on behalf of other nodes than the nodes that are lower in the
hierarchy.
5.Mesh Topology
A Mesh topology Provides each device with a point-to-point connection to every other device in
the network. These are most commonly used in WAN's, which connect networks over
telecommunication links. Mesh topologies use routers to determine the best path. Mesh networks
provide redundancy, in the event of a link failure, meshed networks enable data to be routed
through any other site connected to the network. Because each device has a point-to-point
connection to every other device, mesh topologies are the most expensive and difficult to
maintain.
Mesh networks differ from other networks in that the component parts can all connect to each
other via multiple hops, and they generally are not mobile. Mobile ad-hoc networking
(MANET), featured in many consumer devices, is a subsection of mesh networking. Mesh
networks are self-healing: the network can still operate even when a node breaks down or a
connection goes bad. As a result, a very reliable network is formed.
This concept is applicable to wireless networks, wired networks, and software interaction. There
are three distinct generations of wireless mesh architectures. In the first generation one radio
provides both backhaul (packet relaying) and client services (access to a laptop). In the second
generation, one radio relayed packets over multiple hops while another provided client access.
This significantly improved backhaul bandwidth and latency. Third generation wireless mesh
products use two or more radios for the backhaul for higher bandwidth and low latency. Third
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generation mesh products are replacing previous generation products as more demanding
applications like voice and video need to be relayed wirelessly over many hops of the mesh
network.
6. Hybrid
Hybrid networks use a combination of any two or more topologies in such a way that the
resulting network does not exhibit one of the standard topologies (e.g., bus, star, ring, etc.). For
example, a tree network connected to a tree network is still a tree network topology. A hybrid
topology is always produced when two different basic network topologies are connected. Two
common examples for Hybrid network are: star ring network and star bus network
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A Star ring network consists of two or more star topologies connected using
a multistation access unit (MAU) as a centralized hub.
A Star Bus network consists of two or more star topologies connected using a bus
trunk (the bus trunk serves as the network's backbone).
While grid and torus networks have found popularity in high-performance
computing applications, some systems have used genetic algorithms to design custom networks
that have the fewest possible hops in between different nodes. Some of the resulting layouts are
nearly incomprehensible, although they function quite well.
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