‘Wireless
Fidelity’
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 1

Wi-Fi is the name given to the IEEE 802.11 wireless networking protocol
family.
Why Wi-Fi …
1. T rul M O B ILE.
y
2. N o D angl C ab l O R W ires.
ing es
3. U ses an U N -Licensed part of the R ad io S pectrum , this m eans l
ess restrictions
in m any countries.
Problems…
1. H eavy LAN cannot b e carried out.
2. N etw ork C ongestion.
3. H eavy LAN cannot b e carried .
WPA:
“W i-F i P rotected Access” a security protocol suite that has repl
, aced W EP ,
using a com pl and untilnow , secure system of authentication.
ex,
WEP:
“W irel
ess Equival P rivacy”an ol er security protocol that w as used w id el
ent , d y
in ol er Aps to provid e security. W EP is now consid ered rel
d ativel insecure.
y
SSID:
“S ervice S et Id entifier”is a 32-b it character unique id entifier attached to the
,
head er of packet transm itted over W LAN . S S ID d ifferentiates one W LAN from one
another, so that al AP s and d evices attem pting to connect to a specific W LAN m ust
l
use the sam e S S ID . It is al referred to as a N ET W O R K N AM E.
so
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 2

Wi-Fi Technical Details: -
1. The term wireless networking refers to technology that enables two or more
computers to communicate using standard network protocols.
2. Wi-Fi is the name given to the IEEE 802.11 wireless networking protocol family.
3. The main difference between Wi-Fi and Cellular is that Wi-Fi is implemented in
Unlicensed Bands.
4. Wi-Fi networks have limited range. A typical router using 802.11b or 802.11g
standards might have a range of about 150 feet (46 meters).
Jargon Buster :
• Access Point (AP) : It is a piece of Hardware which connects wireless adapters
to the backend servers that provide the necessary infrastructure to connect to
the Internet.
• Wireless Adapter : It is the wireless replacement for the network interface
(LAN) card – available in the PCI and PCMCIA interface.
• Wireless Bridge : In this mode, two APs can be bridged with each other for
communication. It is used when networks of two buildings such as offices are to
be connected wirelessly.
• WPA : “Wi-Fi Protected Access”, a security protocol suite that has replaced WEP,
using a complex, and until now, secure system of authentication.
• WEP : “Wireless Equivalent Privacy”, an older security protocol that was used
widely in older Aps, to provide security. WEP is now considered relatively
insecure.
• SSID : Service Set Identifier is a 32-bit character unique identifier attached to
the header of packet transmitted over WLAN. SSID differentiates one WLAN
from one another. It is also referred to as a NETWORK NAME
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 3

Seminar Topic – Wireless Fidelity
Name – Manan Kakkar
WIRELESS FIDELITY
T aking into consid eration the recent d evel opm ents in the fiel of d ata com m unication, I
d
thought that this w as the right pod ium to introd uce to you the l atest technol ogy that this the tal of
k
C orporate Ind ia, consid ered as the next b ig thing to hit Ind ia after the M ob il B oom , W i-F i certainl
e y
is m aking its presence fel t.
S trol d ow n the l
l eisurel surround ings of D el s B usiness cl
y hi’ ass hotel and stay connected .
s
P op in for a quick sw im at M um bai’ hotel
s s-stil connected . A coffee b reak is no m ore a excuse to
l
go O ffl anym ore- Bangalore’ Java C ity range of Coffee Shops and other hangout spots too
ine s
offer Wi-Fi connectivity.
Wi-Fi in simple terms is Wireless LAN or Internet connection. P D As, etc. tod ay are
read il provid ing W i-F i connectivity. W el the l
y l uxury of sitting b y the pool e sipping col d rinks
sid d
and surfing on the N et d oes m ake it reasonab l e.
Simply Why Wi-Fi…
1. T rul M O B ILE.
y
2. N o D angl C ab l O R W ires.
ing es
3. C an w ork w ith P D As.
4. D ata R ates of 54 M b ps at 2.4 GH z.
5. C an w ork in 2 m od es : Ad -hoc & B ase S tn.
6. B est suited for C orporates w ith severalem pl oyees m oving around w ith Laptop s.
7. U ses an unl icensed p art of the rad io spectrum , this m eans l
ess regulatory control in m any
s
countries.
T he term wireless networking refers to technology that enables tw o or m ore computers to
communicate using standard network protocols, b ut w ithout netw ork cab l ing. S trictl speaking,
y
any technol ogy that d oes this coul b e caled w irel
d l ess netw orking. H ow ever our d iscussion tod ay
is l ited to w irel
im ess LAN s. T his technol ogy, has prod uced a num b er of afford ab l w irel
e ess
solutions that are grow ing in p opul arity w ith b usiness and school as w el as sop histicated
s l
applications w here netw ork w iring is im possib l such as in w arehousing or p oint-of-sal hand hel
e, e d
equipm ent.
Getting d ow n to the technical
ities, Wi-Fi is the name given to the IEEE 802.11 wireless
networking protocol family. T he W i-F i – 802.11b cam e first w orking at 2.4GHz offering 11
Mbps, w el m an’ d esire of m ore l to the d evel
l s ed opm ent of 802.11a w hich w orked at 5 GHz b ut
gave 54Mbps data rate. T rying to red uce operating frequencies w hil m aintaining the D ata R ate
e
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 4

the 802.11g stand ard w as d evel
oped w hich is now w id el used and gives 54Mbps data rate at
y
2.4GHz frequency. T he ‘ & ‘ ’ stand ard s are com patib l w ith each other as their operating
g’ b e
frequencies are sam e.
T he m ain difference between cellular technology and Wi-Fi is that cellular system use
licensed spectrum, and Wi-Fi is implemented in unlicensed bands. T he econom ic b asis for
their im pl entation is therefore com pl y d ifferent. the success of W i-F i has m ad e m any peop l
em etel e
look to unl icensed sp ectrum as the future of w irel
ess access, rather than spectrum l icensed and
controled b y l
l arge corporations.
• Wi-Fi networks have limited range. A typical Wi-Fi home router using 802.11b or
802.11g might have a range of 150 ft (46 m) indoors and 300 ft (92 m) outdoors.
W i-F i operates in two modes – Ad-Hoc & Base station.
3 friend s in a park exchanging d ata over their W i-F i enab l Laptops is an exam pl of A d -
ed e
H oc m od e.
An ad -hoc, or peer-to-peer w irel ess netw ork consists of a num b er of com puters each equipped
w ith a w ireless netw orking interface card . Each com puter can com m unicate d irectl w ith al of the
y l
other w irel ess enab l com puters. T hey can share fil and printers this w ay, b ut m ay not b e ab l
ed es e
to access w ired LA N resources, unl ess one of the com puters acts as a b rid ge to the w ired LA N
using specialsoftw are. (T his is caled "b rid ging")
l
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 5

Figure 1: Ad-Hoc or Peer-to Peer Networking.
Each com puter w ith a w irel
ess interface can com m unicate d irectl w ith al of the others.
y l
W ith appropriate netw orking softw are supp ort, users on the w irel
ess LA N can share fil and
es
printers l
ocated on the w ired LAN and vice versa.
W hereas if one of the term inal is connected to an Access P oint w hich is further connected
s
to a b ackend server is a B ase S tation m od e. In this type of netw ork the access point acts
l a hub , provid ing connectivity for the w irel
ike ess com puters. It can connect (or "b rid ge") the
w irel
ess LA N to a w ired LA N , alow ing w irel
l ess com puter access to LAN resources, such as
fil servers or existing Internet C onnectivity. There are two types of access points:
e
i. D ed icated Hardware Access Points (H AP ) such as, A ppl e's Airport B ase
S tation.H ard w are access points offer com prehensive support of m ost w irel
ess features,
b ut check your requirem ents carefuly.l
ii. Software Access Points w hich run on a com puter equip ped w ith a w irel ess netw ork
interface card as used in an ad -hoc or peer-to-peer w irel
ess netw ork.
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 6

Figure 2: Hardware Access Point.
W irel
ess connected com puters using a H ard w are Access P oint.
Figure 3: Software Access Point.
W irel
ess connected com puters using a S oftw are Access P oint.
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 7

1. What is the range of a wireless network?
Each access point has a finite range w ithin w hich a w irel ess connection can b e m aintained
b etw een the cl ient com puter and the access point. T he actuald istance varies d epend ing upon the
environm ent; m anufacturers typicaly state b oth ind oor and outd oor ranges to give a reasonab l
l e
ind ication of rel l perform ance. Al it shoul b e noted that w hen op erating at the l its of
iab e so d im
range the perform ance m ay d rop, as the qual of connection d eteriorates and the system
ity
com pensates. T ypical ind oor ranges are 150-300 feet, b ut can b e shorter if the b uil ing d
construction interferes w ith rad io transm issions. Longer ranges are possib l b ut perform ance w il
e, l
d egrad e w ith d istance. O utd oor ranges are quoted up to 1000 feet, b ut again this d epend s up on
the environm ent. T here are w ays to extend the b asic operating range of W irel ess com m unications,
b y using m ore than a singl access point or using a w irel
e ess rel /extension point.
ay
2. How many wireless networked computers can use a single access
point?
T his d ep end s upon the m anufacturer. S om e hard w are access points have a recom m end ed
l it of 10, w ith other m ore expensive access points supporting up to 100 w irel
im ess connections.
U sing m ore com puters than recom m end ed w il cause perform ance and rel il to suffer.
l iab ity
S oftw are access points m ay al im pose user l itations, b ut this d epend s upon the specific
so im
softw are, and the host com puter's ab il to process the required inform ation.
ity
3. Can we have more than one access point?
Y es, m ul l access p oints can b e connected to a w ired LAN , or som etim es even to a second
tip e
w irel
ess LAN if the access point supports this. In m ost cases, separate access points are
interconnected via a w ired LA N , provid ing w irel
ess connectivity in specific areas such as offices or
classroom s, b ut connected to a m ain w ired LAN for access to netw ork resources, such as fil e
servers.
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 8

Figure 4: Multiple Access Points.
W irel
ess connected com puters using M ul e Access P oints.
tipl
If a singl area is too l
e arge to b e covered b y a singl access point, then m ul e access points or
e tipl
extension points can b e used . -- N ote that an "extension point" is not d efined in the w irel
ess
stand ard , b ut have b een d evel ed b y som e m anufacturers. W hen using m ul e access points,
op tipl
each access point w irel ess area shoul overl its neighb ors. T his provid es a seam l
d ap ess area for
users to m ove around in using a feature caled "roam ing. " (S ee the next q uestion for an
l
exp lanation of R oam ing)
S om e m anufacturers prod uce extension points, w hich act as w irel
ess rel
ays, extend ing the range
of a singl access point. M ul e extension points can b e strung together to provid e w irel
e tipl ess
access to far aw ay l
ocations from the centralaccess point.
Figure 5: Extension Point.
W irel
ess connected com puters using an Access P oint w ith an Extension P oint.
(Figure)
4. What is Roaming?
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 9

A w irel
ess com puter can "roam " from one access point to another, w ith the softw are and
hard w are m aintaining a stead y netw ork connection b y m onitoring the signalstrength from in-range
access points and l ocking on to the one w ith the b est qual ity. U sualy this is com pl y
l etel
transparent to the user; they are not aw are that a d ifferent access point is b eing used from area to
area. S om e access point configurations require security authentication w hen sw app ing access
points, usualy in the form of a passw ord d ial b ox.
l og
Access points are req uired to have overl ping w irel
ap ess areas to achieve this as can b e seen
in the folow ing d iagram :
l
Figure 6: Roaming.
A user can m ove from Area 1 to Area 2 transparentl T he W irel
y. ess netw orking hard w are
autom aticaly sw aps to the Access P oint w ith the b est signal
l .
N ot al access points are capab l of b eing configured to support roam ing. Al of note is that any
l e so
access points for a singl vend or shoul b e used w hen im pl enting roam ing, as there is no
e d em
officialstand ard for this feature.
5. If my computer is connected to a wireless LAN, can it
communicate with computers on a wired LAN as well?
T o d o this you w il need som e sort of b rid ge b etw een the w irel
l ess and w ired netw ork. T his can
b e accom pl ished either w ith a hard w are access point or a softw are access point. H ard w are access
points are avail l w ith various types of netw ork interfaces, such as Ethernet or T oken R ing, b ut
ab e
typicaly require extra hard w are to b e purchased if your netw orking req uirem ents change. If
l
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 10

netw orking requirem ents go b eyond just interconnecting a w ired netw ork netw ork to a sm al
l
w irel
ess netw ork, a softw are access point m ay b e the b est sol
ution.
A softw are access point d oes not l it the type or num b er of netw ork interfaces you use. It m ay
im
al alow consid erab l fl
so l e exib il in provid ing access to d ifferent netw ork types, such as d ifferent
ity
types of Ethernet, W irel ess and T oken R ing netw orks. S uch connections are onl l ited b y the
y im
num b er of sl or interfaces in the com puter used for this task. F urther to this the softw are access
ots
point m ay incl e significant ad d itional features such as shared Internet access, w eb caching or
ud
content fil
tering, provid ing significant b enefits to users and ad m inistrators.
6. Can we use a wireless network to interconnect two LANs?
Y es. W ireless netw orking offers a cost-effective sol ution to users w ith d ifficul physical
t
instalations such as cam puses, hospital or b usinesses w ith m ore than one l
l s ocation in im m ed iate
proxim ity b ut separated b y p ub l thoroughfare. T his type of instalation requires tw o access
ic l
points. Each access point acts as a b rid ge or router connecting its ow n LAN to the w irel ess
connection. T he w ireless connection alow s the tw o access points to com m unicate w ith each
l
other, and therefore interconnect the tw o LAN 's.
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 11

Figure 7: LAN to LAN Wireless Communications:
A H ard w are Access P oint provid ing w irel
ess connectivity to l
ocalcom puters and a softw are
access point. T he softw are access point provid es W ired Ethernet netw ork 2 com puters access to
W ired N etw ork 1.
N ote that not al hard w are access points have the ab il to d irectl interconnect to another
l ity y
hard w are access point, and that the sub ject of interconnecting LA N 's over w irel
ess connections is
al arge and com pl one, and is b eyond the scope of this introd uction.
ex
7. How to use a wireless network to share an Internet connection?
T o share an Internet connection across a LAN you need tw o things:
a. an Internet sharing hard w are d evice or softw are program
b . a LAN
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 12

If your LAN is w irel
ess, the sam e criteria appl Y ou need a hard w are or softw are access point and
y.
a w ireless LAN . Any com puter equip ped w ith a w ireless netw ork card running suitab l Internet
e
sharing softw are can b e used as a softw are access p oint. A num b er of vend ors offer hard w are
access points.
A hard w are access point m ay provid e Internet S haring capab il ities to W ired LAN
com puters, b ut d oes not usualy p rovid e m uch fl
l exib il b eyond very sim pl configurations.
ity e
Figure 8: Software Access Point.
W irel
ess connected com puters using a S oftw are Access P oint for shared Internet access.
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 13

Figure 9: Hardware Access Point.
W irel
ess connected com puters using a H ard w are Access P oint for shared Internet access.
8. If I have more than one hardware access point, how can I share a
single Internet connection?
If an existing w ired LAN alread y has an Internet connection, then the hard w are access points
sim pl connect to your LAN and alow w irel
y l ess com puters to access the existing Internet
connection in the sam e w ay as w ired LAN com puters.
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 14

Figure 10: Multiple Access Points.
W irel
ess connected com puters using M ul e Access P oints.
tipl
If there is no existing Internet connection, then this d epend s on the access point:
Figure 11: Software Access Point sharing one Internet connection.
W irel
ess connected com puters using M ul e Access P oints. Al w ired and w irel
tipl l ess com puters
access the Internet through a singl softw are access point.
e
(Figure)
If an access point provid es som e form of Internet sharing itsel then having m ul e such
f, tipl
access points connected to a w ired LA N m ay require som e specialconfiguration, or possib l m ay
y
require an ad d itionalInternet sharing d evice or softw are program .
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 15

9. Is it true that wireless networking is only good for laptop
computers?
Al though w irel
ess netw orking offers ob vious b enefits to users of l aptops w ho m ove from
location to location throughout the d ay, there are b enefits for users of fixed p osition com puters as
w el. M any school and b usinesses have unsuitab l b uil ing l
l s e d ayouts or w als that cannot b e w ired
l
for various reasons m aking it d ifficul or im p ossib l to b uil a w ired netw ork. W irel
t e d ess netw orking
in these environm ents is a very cost effective al ternative al provid ing future fl
so exib il In cases
ity.
w here a sm al num b er of com puters are separated from a m ain netw ork a w irel
l ess l m ay b e
ink
m ore cost effective than netw ork cab l ing al though the l atter is perfectl feasib l T em porary
y e.
w ireless LAN s can easil b e created for exhib itions, school or b usiness p rojects, al w ithout any
y l
trail cab l
ing ing.
Problems faced by a Wi-Fi network…
1. Security is the biggest concern.
T he signalb eing R F is freel transm itted in air, hence anyone in the vicinity of the AP can
y
access the d ata. T o overcom e w e use S S ID .
W P A (W irel
ess P rotected Access) is one of the w id el used encryption stand ard , it is a
y
successor of the W EP (W ireless Equival P rivacy) .
ent
O ptions such as isol
ating the AP s (W ired & W irel
ess) can hel
p.
2. Network Congestion.
3. Heavy LAN cannot be carried out.
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 16

George B ush d uring P resend ential D eb ate w as rum oured to have b een using
such a d evice
‘Wireless Fidelity’ by Manan Kakkar, Thakur Polytechnic, Mumbai 17