A REPORT ON
WI-FI TECHNOLOGY
Contents Page
1)
Abstract
2)
Introduction
a) Background
b) Objectives
3)
Literature Review
4)
History of Wi-Fi
5)
Wi-Fi standards and development history
6)
Working OF Wi-Fi
7) Wi-Fi network topography
8)
Use of Wi-Fi technology
9)
Wi-Fi security
10)
Advantages & Disadvantages
11) Conclusion
Abstract
WiFi,
an acronym for “Wireless fidelity “is a set of product compatibility standards
for Wireless Local Area Networks (WLAN) based on the IEEE 802.11 specifications.
It enables a person with a wireless- enabled computer or personal digital
assistant (PDA) to connect to the internet when in proximity of an access
point.
Technology is making rapid progress and is making many things easier. As
the innovative thinking of persons is increasing day-by-day , new methods for
wireless networking has been evolved of which our present topic WiFi is the
most accepted technology.
LiFi
stands for Light Fidelity. The term LiFi refers to visible light communication
(VLC) technology that uses light as medium to deliver high-speed communication
in a manner similar to WiFi and complies with the IEEE standard IEEE 802.15.7.
The IEEE 802.15.7 is a high-speed, bidirectional and fully networked wireless
communication technology based standard similar to WiFi’s IEEE 802.11.
WiFi is of major use for general wireless
coverage within building, WIFi an acronym for
wireless-fidelity which is the wireless way to handle networking. The main aim
of this report is wireless networking achieved by WiFi.
This report introduces
WiFi technology and states the history of this technology in brief. We then
deal with the different ways of wireless networking, connecting WiFi and with
WiFi security. This report concludes with the pros and cons of this technology
and its future. WiFi goes beyond wireless connecting computers, it also
connects people.
INTRODUCTION
Background
·
WiFi stands for Wireless Fidelity. WiFi It is based on the IEEE 802.11
family of standards and is primarily a local area networking (LAN) technology
designed to provide in-building broadband coverage.
·
Current WiFi systems support a peak physical-layer data rate of 54 Mbps
and typically provide indoor coverage over a distance of 100 feet.
·
WiFi has become the de facto standard for last mile broadband
connectivity in homes, offices, and public hotspot locations. Systems can
typically provide a coverage range of only about 1,000 feet from the access
point.
·
WiFi offers remarkably higher peak data rates than do 3G systems,
primarily since it operates over a larger 20 MHz bandwidth, but WiFi systems
are not designed to support high-speed mobility.
·
One significant advantage of WiFi over WiMAX and 3G is its wide
availability of terminal devices. A vast majority of laptops shipped today have
a built-in WiFi interface.
·
WiFi interfaces are now also being built into a variety of devices,
including personal data assistants (PDAs), cordless phones, cellular phones,
cameras, and media players.
·
The name Wi-Fi, commercially used at least as early as August 1999,
was coined by the brand-consulting firm Interbrand. The Wi-Fi Alliance had
hired Interbrand to create a name that was "a little catchier than 'IEEE
802.11b Direct Sequence'."Phil Belanger, a founding member of the Wi-Fi
Alliance who presided over the selection of the name "Wi-Fi", has
stated that Interbrand invented Wi-Fi as a pun upon the
word hi-fi.
·
Interbrand also created the
Wi-Fi logo. The yin-yang Wi-Fi logo indicates the certification
of a product for interoperability.
·
The Wi-Fi Alliance used the nonsense advertising
slogan "The Standard for Wireless Fidelity" for a short time
after the brand name was created. The name was, however, never officially
"Wireless Fidelity”. Nevertheless, the Wi-Fi Alliance was also called the
"Wireless Fidelity Alliance Inc" in some publications and the
IEEE's own website has stated "WiFi is a short name for Wireless
Fidelity".
·
Non-Wi-Fi technologies intended for fixed points, such as Motorola
Canopy, are usually described as fixed wireless. Alternative wireless
technologies include mobile phone standards, such as 2G, 3G, 4G,
and LTE.
·
The name is sometimes written as WiFi, WiFi, or WiFi, but
these are not approved by the WiFi Alliance.
The
objective of this report is to provide knowledge about WiFi and LiFi technology
to all those interested readers. The WiFi and LiFi technology has immense
potential in future to build our lives. There are many more interesting areas
in WiFi and LiFi context to explore and research and give the benefit of it to
the world. We would like the readers to read this report and build interest in
this field. The motive of this report is to make people aware about WiFi and
LiFi technology and its wide spread applications in our daily lives.
Literature reviews
· · We did a literature study focusing on WiFi
technology, and its comparison with other technologies. All related information
is gathered from websites, e-books, online articles and journals, other
internet sources and library books.
· · There was some difficulty about finding
particular information (like frequency, upstream and downstream speed) because
we have to make certain tables and comparisons of different technologies (like
3G, 4G, 5G, LTE, and WiMax) with WiFi. After carefully analyzing all gathered
information, it is presented in organized form, like comparisons and tables.
· · We gathered all the required information, and
checked with at least two sources, assuring that it is true information. After
gathering information and study analysis, the results of an extensive survey,
and literature reviews about different wireless technologies are summarized in
result section.
The history of WiFi
The history of WiFi is long and
interesting. In 1971, ALOHAnet connected the Hawaiian Islands with a UHF wireless packet
network. ALOHAnet and the ALOHA protocol were early forerunners to Ethernet, and later the IEEE 802.11 protocols, respectively.
Vic Hayes is often regarded as the
“father of Wi-Fi.” He started such work in 1974 when he joined NCR Corp., now
part of semiconductor components maker Agree Systems.
A 1985 ruling by the U.S. Federal
Communications Commission released the ISM band for unlicensed use – these are frequencies
in the 2.4GHz band. These frequency bands are the same ones used by equipment
such as microwave ovens and are subject to interference.
In 1991, NCR Corporation with AT&T Corporation invented the precursor to
802.11, intended for use in cashier systems. The first wireless products were
under the name Wave
LAN. They are
the ones credited with inventing Wi-Fi.
The Australian radio-astronomerJohn
O’Sullivan
with his colleagues Terence Percival, Graham Daniels, Diet Ostryand John Deane
developed a key patent used in Wi-Fi as a by-product of a Commonwealth Scientific
and Industrial Research Organization (CSIRO) research project, “a failed experiment to
detect exploding mini black holes the size of an atomic particle”.
In 1992 and 1996, CSIRO obtained patents
for a method later used in Wi-Fi to “unsmear” the signal.
The first version of the 802.11 protocol was released in 1997, and
provided up to 2 Mb/s link speeds. This was updated in 1999 with 802.11b to permit 11 Mb/s link
speeds, and this proved to be popular.
WiFi Standards and Development History
802.11-1997 (802.11
legacy)
The original version of the standard
IEEE 802.11 was released in 1997 and clarified in 1999, but is now obsolete. It
specified two net bit rates of 1 or 2 megabits per second (Mb/s), plus forward error correction code. It specified three
alternative physical layer technologies: diffuse infrared operating at 1 Mb/s; frequency-hopping spread spectrum operating
at 1 Mb/s or 2 Mb/s; and direct-sequence spread spectrum operating at 1
Mb/s or 2 Mb/s. The latter two radio technologies used microwave transmission over the Industrial Scientific Medical
frequency band at 2.4 GHz. Some earlier WLAN technologies used lower
frequencies, such as the U.S 900 MHz ISM band.
802.11b (1999)
The 802.11b standard has a maximum
raw data rate of 11 Mbit/s, and uses the same media access method defined in
the original standard. 802.11b products appeared on the market in early 2000,
since 802.11b is a direct extension of the modulation technique defined in the
original standard. The dramatic increase in throughput of 802.11b (compared to
the original standard) along with simultaneous substantial price reductions led
to the rapid acceptance of 802.11b as the definitive wireless LAN technology.
Devices using 802.11b experience
interference from other products operating in the 2.4 GHz band. Devices
operating in the 2.4 GHz range include microwave ovens, Bluetooth devices, baby
monitors, cordless telephones, and some amateur radio equipment.
802.11a (2012, OFDM waveform)
Originally described as clause 17 of
the 1999 specification, the OFDM waveform at 5.8 GHz is now defined in clause
18 of the 2012 specification, and provides protocols that allow transmission
and reception of data at rates of 1.5 to 54 Mbit/s. It has seen widespread
worldwide implementation, particularly within the corporate workspace. While
the original amendment is no longer valid, the term 802.11a is still
used by wireless access point (cards and routers) manufacturers to describe
interoperability of their systems at 5 GHz, 54 Mbit/s.
The 802.11a standard uses the same
data link layer protocol and frame format as the original standard, but an OFDM based air interface (physical
layer). It operates in the 5 GHz band with a maximum net data rate of 54
Mbit/s, plus error correction code, which yields realistic net achievable
throughput in the mid-20 Mbit/s.
Since the 2.4 GHz band is heavily
used to the point of being crowded, using the relatively unused 5 GHz band
gives 802.11a a significant advantage. However, this high carrier frequency also brings a
disadvantage: the effective overall range of 802.11a is less than that of
802.11b/g. In theory, 802.11a signals are absorbed more readily by walls and
other solid objects in their path due to their smaller wavelength, and, as a
result, cannot penetrate as far as those of 802.11b. In practice, 802.11b
typically has a higher range at low speeds (802.11b will reduce speed to 5.5
Mbit/s or even 1 Mbit/s at low signal strengths). 802.11a also suffers from
interference, but locally there may be fewer signals to interfere with,
resulting in less interference and better throughput.
802.11g (2003)
In June 2003, a third modulation
standard was ratified: 802.11g. This works in the 2.4 GHz band (like 802.11b),
but uses the same OFDM based transmission scheme
as 802.11a. It operates at a maximum physical layer bit rate of 54 Mbit/s
exclusive of forward error correction codes, or about 22 Mbit/s average
throughput.
802.11g hardware is fully backward
compatible with 802.11b hardware, and therefore is encumbered with legacy
issues that reduce throughput by ~21% when compared to 802.11a.
The then-proposed 802.11g standard
was rapidly adopted in the market starting in January 2003, well before
ratification, due to the desire for higher data rates as well as to reductions
in manufacturing costs. By summer 2003, most dual-band 802.11a/b products
became dual-band/tri-mode, supporting a and b/g in a single mobile adapter card or access point. Details
of making b and g work well together occupied much of the lingering technical
process; in an 802.11g network, however, activity of an 802.11b participant
will reduce the data rate of the overall 802.11g network.
Like 802.11b, 802.11g devices suffer
interference from other products operating in the 2.4 GHz band, for example
wireless keyboards.
802.11 (2007)
In 2003, task group TGma was
authorized to “roll up” many of the amendments to the 1999 version of the
802.11 standard. REVma or 802.11ma, as it was called, created a single document
that merged 8 amendments (802.11a, b, d, e, g, h, i, j) with the base standard. Upon approval on March 8, 2007,
802.11REVma was renamed to the then-current base standard
IEEE 802.11-2007.
802.11n (2009)
802.11n is an amendment that improves
upon the previous 802.11 standards by adding multiple-input multiple-output antennas (MIMO). 802.11n
operates on both the 2.4 GHz and the 5 GHz bands. Support for 5 GHz bands is
optional. It operates at a maximum net data rate from 54 Mbit/s to 600 Mbit/s.
The IEEE has approved the amendment, and it was published in October 2009.Prior
to the final ratification, enterprises were already migrating to 802.11n
networks based on the Wi-Fi Alliance‘s certification of products
conforming to a 2007 draft of the 802.11n proposal.
802.11 (2012)
In May 2007, task group TGmb was
authorized to “roll up” many of the amendments to the 2007 version of the
802.11 standard. REVmb or 802.11mb, as it was called, created a single document
that merged ten amendments (802.11k, r, y, n, w, p, z, v, u, s) with the 2007 base standard. In addition much cleanup was
done, including a reordering of many of the clauses. Upon publication on March
29, 2012, the new standard was referred to as IEEE 802.11-2012.
802.11ac (2013)
IEEE 802.11ac-2013 is an amendment to
IEEE 802.11, published in December 2013, that builds on 802.11n. Changes
compared to 802.11n include wider channels (80 or 160 MHz versus 40 MHz) in the
5 GHz band, more spatial streams (up to eight versus four), higher-order
modulation (up to 256-QAM vs. 64-QAM), and the
addition of Multi-user MIMO (MU-MIMO). As of October 2013,
high-end implementations support 80 MHz channels, three spatial streams, and 256-QAM,
yielding a data rate of up to 433.3 Mbit/s per spatial stream, 1300 Mbit/s
total, in 80 MHz channels in the 5 GHz band.Vendors have announced plans to
release so-called “Wave 2” devices with support for 160 MHz channels, four
spatial streams, and MU-MIMO in 2014 and 2015.
802.11ad (2010)
IEEE 802.11ad is an amendment that
defines a new physical layer for 802.11 networks to operate in
the 60 GHz millimeter wave spectrum. This frequency band has
significantly different propagation characteristics than the 2.4 GHz and 5 GHz
bands where WiFi networks operate. Products implementing the 802.11ad standard are being
brought to market under the WiGig brand name. The certification program is now
being developed by the Wi-Fi Alliance instead of the now defunct WiGig Alliance. The peak
transmission rate of 802.11ad is 7 Gbit/s.
802.11af (2014)
IEEE 802.11af, also referred to as
“White-Fi” and “Super Wi-Fi” is an amendment, approved in February 2014, that
allows WLAN operation in TV white space spectrum in the VHF and UHF bands between 54 and 790 MHz
It uses cognitive radio technology to transmit on unused TV
channels, with the standard taking measures to limit interference for primary
users, such as analog TV, digital TV, and wireless microphones.Access points
and stations determine their position using a satellite positioning system such
as GPS, and use the Internet to
query a geolocation database (GDB) provided by a regional
regulatory agency to discover what frequency channels are available for use at
a given time and position. The physical layer uses OFDM and is based on
802.11ac.
The propagation path loss as well as
the attenuation by materials such as brick and concrete is lower in the UHF and
VHF bands than in the 2.4 and 5 GHz band, which increases the possible range.
The frequency channels are 6 to 8 MHz wide, depending on the regulatory domain.
Up to four channels may be bonded in either
one or two contiguous blocks.MIMO operation is possible with up to four streams
used for either space–time block code (STBC) or multi-user (MU)
operation. The achievable data rate per spatial stream is 26.7 Mb/s for 6 and
7 MHz channels, and 35.6 Mb/s for 8 MHz channels. With four spatial streams
and four bonded channels, the maximum data rate is 426.7 Mb/s for 6 and 7 MHz
channels and 568.9 Mb/s for 8 MHz channels.
Working of WiFi
WiFi
is high speed internet connection and network connection without use of any
cables or wires. The wireless network is operating three essential elements
that are radio signals, antenna and router.
The radio waves are keys which
makes WiFi networking possible. The computers and cell phones are ready with
WiFi cards.
WiFi compatibility has been using a new creation to constituent
within the ground connected with community network.
The actual broadcast is connected with in
sequence in fact it is completed by way of stereo system surf as well as the
worth of wires with monitors to classification prone.
WiFi allows the person in order to get access to web any place in the
actual provided area. You can now generate a system within resorts, library,
schools, colleges, campus, personal institutes, as well as espresso stores as
well as on the open public spots to help to make your company much more
lucrative as well as interact with their own customer whenever.
WiFi
compatibility can make surf with share to company using their inspiring cable
television much a smaller amount force down.
The
radio signals are transmitted from antennas and routers that signals are picked
up by WiFi receivers, such as computers and cell phones that are ready with
WiFi cards. Whenever the computer receives the signals within the range of
100-150 feet for router it connect the device immediately. The range of WiFi
is depends upon the environment, indoor or outdoor ranges. The WiFi cards will
read the signals and create an internet connection between user and network.
The speed of the device using WiFi
connection increases as the computer gets closer to the main source and speed
is decreases computer gets further away .
Many
new laptops, mobile phones have inbuilt WiFi card you don’t have to do
anything which is one of the best things. If it is of free based type of
network connection the user will be promoted with a login id and password. The
free base network connections also well in some areas. The WiFi network
connection is creating hot spots in the cities. The hotspots are connection
points of WiFi network. It is a small
box that is hardwired in to the network. There are many WiFi hotspots are
available in public places restaurants, airports, hotels, offices and
universities etc.
WiFi network topologies
• AP-based
topology (Infrastructure Mode)
• Peer-to-peer
topology (Ad-hoc Mode)
•
Point-to-multipoint
bridge topology
AP-based topology
•
The client communicates
through Access Point.
•
BSA-RF coverage
provided by an AP.
•
ESA-It consists of 2 or
more BSA.
•
ESA cell includes 10-15%
overlap to allow roaming.
Peer-to-peer topology
•
AP is not required.
•
Client devices within a cell can communicate directly with
each other.
•
It is useful for setting up of a wireless network quickly and
easily
Point-to-multipoint bridge topology
— Buildings
even if the buildings are miles apart.
— These
conditions receive a clear line of sight between buildings.
The
line-of-sight range varies based on the type of wireless bridge and antenna
used as well as the environmental conditions.
USES OF WI-FI TECHNOLOGY
1. Sync Your
Music Library, Photo Library, or Other Files with Your Smartphone USB-Free:
Since
the days of the original iPod, syncing your music (or other files) from your PC
to your portable device required you to dock your device via USB. Wi-Fi syncing
is all the rage these days, though: you can sync your Android
phone with iTunes, Winamp,
or sync your iPhone with
Linux and its photos
with PhotoSync. Furthermore, Android
users can access their phone's SD card with a myriad of apps, like WiFi
File Explorer, Dazzboard,
Android
Manager WiFi, or the accurately
named Awesome Drop.
2. Share
Files with Nearby Computers:
If
you're sharing something other than video between PCs, you
have a bunch of options for transferring
them. While it isn't the absolute fastest method, sharing
files over the same Wi-Fi network
(or an ad-hoc
network if you're out and about) is
certainly one of the easiest ways to get files from one computer to another. Of
course, if the friend with which you're sharing files is a Dropbox enthusiast,
you can transfer
files over Wi-Fi with Dropbox as well.
3. Stream
Movies to Any TV in the House:
Instead
of having a giant collection of DVDs or ripping your movies to every XBMC box
you have in your house, you can build
yourself an affordable home media server
and stream video over Wi-Fi to any other HTPC (or Xbox or Play station)-enabled
TV in the house. Whether you use Windows Media Center,
XBMC,
or a Google, the possibilities
are nearly endless you can use any number of operating systems, applications,
and protocols to get your movies wirelessly from one computer to another.
4. Forward
Notifications from Your Smartphone to Your PC:
If you're rocking an Android phone (and most
of you are), you can send
call, SMS, and battery notifications
straight to your Windows, Mac with Growl, or Linux PC over Wi-Fi with Android
notifier. No more do you have to deal with
the ringing and buzzing phone from across the room when you're already sitting
at your PC. If you prefer to be able to take action on these items, you can
always forego the Wi-Fi and send
them over GTalk with TalkMyPhone
instead.
5. Send
Documents to Your Printer from Any Computer or Smartphone:
There's no reason to have five
different printers in your house just so you can print in any room. Instead of
constantly plugging and unplugging the printer from your laptop, you can print
wirelessly from any computer. Just share
the printer from the computer it's connected to,
turn
it into its own standalone print server
if it doesn't have a computer next to it, or even print
files from your smartphone using Dropbox
(on both Windows and Mac).
6. Turn
Your Smartphone into a Remote Control:
If all the computers in your house are
connected to a WiFi network, you can easily connect your Smartphone to the
same network and control them. With apps like our
favorite iTunes-controlling
Remote
app for iPhone, the encompassing mote
for Android, and more
XBMC remotes than you can shake a stick at,
you don't have to get up from your couch for anything anymore.
7. Tether
Your Smartphone to Your Computer for Internet Anywhere:
Okay,
so we kind of cheated on this one—it does involve connecting to the internet,
but it's definitely not in the traditional way people use Wi-Fi (especially because
you often need a hacked or rooted device to do it). Instead of searching around
for regular Wi-Fi networks wherever you go, you can just use your phone as a
wireless router and connect to your phone's internet service with your PC.
Whether you have a rooted
Android phone and the Wireless Tether
app, a Jailbroken
iPhone with PDAnet, or a manually
hacked-to-tether Palm Pre, you'll never
be without internet again as long as you have cell phone signal, of course.
WiFi Security
Special
precautions must be taken to maintain security in wireless network. However, no
one approach works for all environments and situations. The optimal solution(s)
in a particular network depends on factors such as the level of security
required Size of the network, whether access is required for remote workers,
and so forth.
Securing
WLANs is provided through two processes: Authentication and Encryption.
Authentication is the means by which one STA is verified to have authorization
to communicate with a second STA. In the infrastructure mode Authentication is
established between an AP and each STA. Authentication is a prerequisite for
association. Association is the establishment of communication services between
the STA and the AP, and mapping the STA to the AP to provide the mobile node
with access to the wired LAN.
Authentication
can be either Open System or Shared Key. An Open System, any requesting STA may
be granted authentication. However, success is not guaranteed. The STA
receiving the request may still deny authentication. In Shared Key system only
stations which possess a secret key can be authenticated. Obviously
transmission of the Shared Key could lead to its interception by unauthorized
users. It is therefore encrypted prior to encryption. Shared Key authentication
is available to systems having the optional encryption capability.
Encryption
is intended to provide a level of security comparable to that of a wired LAN.
The encryption algorithm is designated as Wired Equivalent Privacy (WEP). WEP
uses the RC4 PRNG algorithm from RSA Data Security, Inc.
The
WEP algorithm was selected to meet the following cntena:
•
Reasonably Strong.
•
Self-Synchronizing.
•
Computationally Efficient.
•
Exportable.
•
Optional.
Three
well-known methods to secure access to an AP are built into 802.11 networks.
These basic methods are widely available and may be sufficient for some
deployments:
•Service set identifier (SSID)
•Media
Access Control (MAC) address filtering
•Wired
Equivalent Privacy (WEP)
Service
set identifier (SSID):
Network
access control can be implemented using an SSID associated with an AP or group
of APs. The SSID provides a mechanism to "segment" a wireless network
into multiple networks serviced by one or more APs. Each AP is programmed with
an SSID corresponding to a specific wireless network. To access this network,
client computers must be configured with the correct SSID: A building might be
segmented into multiple networks by floor or department. Typically, a client
computer can be configured with multiple SSIDs for users who require access to
the network from a variety of different locations. Because a client computer
must present the correct SSID to access the AP, the SSID acts as a simple
password and thus, provides a measure of security. However, this minimal
security is compromised if the AP is configured to "broadcast" its
SSID. When this broadcast feature is enabled, any client computer that is not
configured with a specific SSID is allowed to receive the SSID and access the
AP. In addition, because users typically configure their own client systems
with the appropriate SSIDs, they are widely known and easily shared.
Media
Access control (MAC) address filtering:
While
an AP or group of APs can be identified by an SSID, a client computer can be
identified by the unique MAC address of its 802.11 network card. To increase
the security of an 802.11 network each AP can be programmed with a list of MAC
addresses associated with the client computers allowed to access the AP. If a
client's MAC address is not included in this list, the client is not allowed to
associate with the AP. MAC address filtering (along with SSIDs) provides
improved security, but is best suited to
small networks where the MAC address list can be efficiently managed.
Each AP must be manually programmed with a list of MAC addresses and the list
must be kept up-to-date. In practice, the manageable number of MAC addresses
filtered is likely to be less than 255 clients. In addition, MAC addresses can
be captured and "spoofed" by another client to gain unauthorized
access to the network.
Wired
Equivalent Privacy (WPE)
Wireless
transmissions are easier to intercept than transmissions over wired networks.
The 802.11 standard currently specifies the WEP security protocol to provide
encrypted communication between the client and an AP. WEP employs the symmetric
key encryption algorithm, Ron's Code 4 Pseudo Random Number Generator (RC4
PRNG). Under WEP, all clients and APs on a wireless network typically use the
same key to encrypt and decrypt data. The 802.11 standard does not specify a
key-management protocol, so all WEP keys on a network usually must be managed
manually unless they are used in conjunction with a separate key-management
protocol. For example, 802.1X provides WEP key management support for WEP is
standard on most current 802.11 cards and APs. WEP specifies the use of a
40-bit encryption key and there are also implementations of 104-bit keys. The
encryption key is concatenated with a 24-bit "initialization vector"
(IV), resulting in a 64- or 128-bit key. This key is input into a pseudorandom
number generator. The resulting sequence is used to encrypt the data to be
transmitted. (WEP keys can be entered in alphanumeric text or hexadecimal
form). WEP encryption has been shown to be vulnerable to attack. Because of
this, static WEP is only suitable for small tightly managed networks with
low-to-medium scanty requirements. In these cases, 128-bit WEP should be
implemented in conjunction with MAC address filtering and SSID (with the
broadcast feature disabled). Customers should change WEP keys on a regular
schedule to further minimize risk. These solutions are also preferable for
large networks. In which the administrative burden of maintaining MAC addresses
on each AP makes this approach impractical The point at which the number of
wireless client systems becomes unmanageable varies depending on the
organization's ability to administer the network, The choice of security
methods (SSID. WEP and MAC address filtering), and its tolerance for risk. If
MAC address filtering is used on a wireless network, the fixed upper limit is
established by the maximum number of MAC addresses that can be programmed into
each AP used in an installation This upper limit varies, but the practical
problem of manually entering and maintaining valid MAC addresses in every AP on
a network limits the use of MAC address filtering to smaller networks.
Virtual
Private Network (VPN), as well as the
upcoming IEEE 802.11i standard addresses weaknesses in 802.11 native
security Both VPN and 802.11i-based security solutions provide better security
and scale well to large networks. As The IEEE 802.lli standard was explained in
the last section, we will discuss now the VPN's.
VPN: Virtual
Private Network technology (VPN) has been used to secure communications among
remote locations via the Internet since the 1990.
A familiar and already
widely used technology in the enterprise, it can readily be extended to WiFi
WLAN segments on existing wired networks.
Although VPNs were originally
developed to provide point-to-point encryption for long Internet connections
between remote users and their corporate networks; they have recently been
deployed in conjunction with Wi-Fi WLAN.
When a WLAN client uses a VPN tunnel,
communications data remains encrypted until it reaches the VPN gateway. Which
sits behind the wireless AP Thus, Intruders are effectively blocked from
intercepting all network communications.
Since the VPN encrypts the entire link
from the PC to the VPN gateway in the heart of the corporate network, the
wireless network segment between the PC and the AP is also encrypted This is
why VPNs have been recommended to help secure WiFi.
Advantages
•Flexible: With a
wireless network you and your staff can have uninterrupted access to people,
information and tools as you and they move through the workplace with your
mobile PC.
•Responsive: As you
change your business operations your wireless network can change with you.
•Customized:
Your wireless network can be configured the way you want it.-even combined
with your current wired network.
•Fast:
From 11 to 54 Mbps throughput and advanced roaming capabilities provide
reliable access to e-mail, the Internet, file sharing and other network
resources away from the desk.
•Cost-effective:
Expand and extend your existing network by simply adding more adapters and
access points. Planning is a no brainier as you need to buy only what you need.
•Secure: Current standards
utilize 64- and 128-bit WEP encryption and help guard the network from
intruders and protect data in transit. Add in technology and you have increased
WLAN protection important for mission-critical data.
In addition to the hard benefits of
increased efficiency, productivity, manageability and cost savings, wireless
networks will certainly make This is a technology incredible to the world.
Disadvantages
•Spectrum
assignments and operational limitations are not consistent worldwide.
•
Power consumption is fairly high compared to some other low-bandwidth
standards.
•Wi-Fi pollution, or
an excessive number of access points in the area, especially on the same or
neighboring channel, can prevent access and interfere with the use of other access
points by others.
•It has a limited
bandwidth of about 83.5 MHz
• Frequency spectrum
used by IEEE 802.11b is shared by many other systems like microwave ovens,
cordless phones etc. This frequency sharing causes interference problem.
Security techniques are not reliable yet.
Conclusion
WiFi provides
freedom: freedom to physically move around your home or business and still stay
connected to the Internet or local network; freedom to grow and move an office
or business without having to install new cables and wires; freedom to be
connected while traveling and on the road.
Wireless Hotspots
(airports, hotels, coffee shops, convention centers and any other place where
someone can connect to a wireless network) are being installed worldwide, all
this means Wi-Fi truly does provide unprecedented freedom. Plus, it is cool,
and it is fun as those in the know say, Once you go wireless, you will never
want to use a cable again. There are real and measurable benefits to using a
wireless network versus a standard wired network.
For a home
installation customer, the greatest benefit is that there are no wits needed:
you don’t need to drill holes in walls and floors; you don’t need to drag
cables or hide them under rugs. One WiFi access point can provide network
access for any typically sized home, and if you live in a rental or a historical
building, you may not be allowed to drill holes-that makes wireless your only
solution.
Wi-Fi use is growing fast in homes, public access areas
and businesses- both large and small. The Wi-Fi Alliance is active with many
industry organizations and is working closely with manufacturers to make sure
that existing Wi-Fi gear is compatible with wireless technologies developed in
future
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