Wi-Fi, also known as wireless fidelity, allows devices to connect to the internet without cables. It uses radio waves to transmit and receive data between devices within range of a wireless access point. Common Wi-Fi standards include 802.11b, 802.11a, and 802.11g. A Wi-Fi network requires an access point connected to a wired network, wireless network cards or adapters in devices, and may include additional components like antennas, bridges, and firewalls for security. Wi-Fi provides mobility and flexibility but can experience interference issues and has a limited range compared to wired connections.

1. Kataria Arvind P.

2.  Wi-Fi, or Wireless Fidelity, is freedom: it
allows a person to connect to the Internet
 Wi-Fi is a wireless technology. Wi-Fi
enabled computers send and receive data
indoors and out; anywhere within the range of
a base station.
 Its just as fast as a cable modem
connection.
 Allows you to access the Internet while on
the move ; you can remain online while
moving from one area to another, without a
disconnection or loss in coverage.

3.  Wireless Technology is commonly
used for connecting devices in wireless
mode.
Wi-Fi (Wireless Fidelity) is a generic
term that refers to the IEEE 802.11
communications standard for Wireless
Local Area Networks (WLANs).
Wi-Fi Network connect computers to
each other, to the internet and to the
wired network.
it is possible to create high-speed
wireless local area networks

4. Why Wi-Fi?
 Setup Cost – Reduced cabling required
 Flexibility – Quick and easy to setup in
temp or permanent space
 Scaleable – Can be expanded with
growth
 Freedom – You can work from any
location that you can get a signal
 Lower total cost of ownership – Because
s of affordability and low install cost
Additionally

5. THE WI-FI TECHNOLOGY
 Wi-Fi Networks use Radio Technologies to transmit
& receive data at high speed:
 IEEE 802.11b
 IEEE 802.11a
 IEEE 802.11g

6. IEEE 802.11B
 Appear in late 1999
 Operates at 2.4GHz radio spectrum
 11 Mbps (theoretical speed) - within 30 m Range
 4-6 Mbps (actual speed)
 100 -150 feet range
 Most popular, Least Expensive
 Interference from mobile phones and Bluetooth devices
which can reduce the transmission speed.

7. IEEE 802.11A
 Introduced in 2001
 Operates at 5 GHz (less popular)
 54 Mbps (theoretical speed)
 15-20 Mbps (Actual speed)
 50-75 feet range
 More expensive
 Not compatible with 802.11b

8. IEEE 802.11G
 Introduced in 2003
 Combine the feature of both standards (a,b)
 100-150 feet range
 54 Mbps Speed
 2.4 GHz radio frequencies
 Compatible with ‘b’

9. What do you need to
do Wi -fi?
 Existing wired network/services
(Infrastructure Mode)
 DHCP/DNS
 Access point
 Antennas and bridges
 Wireless adapter

10. How Wi-Fi works
 If you've been in an airport, coffee
shop, library or hotel recently chances are you've
been right in the middle of a wireless network.
 Many people also use wireless networking, also
called Wi-Fi to connect their computers at home , and
some cities are trying to use the technology to provide
free or low-cost internet access to residents.

11. ELEMENTS OF A WI-FI NETWORK
 Access Point (AP) - The AP is a
wireless LAN transceiver or “base
station” that can connect one or many
wireless devices simultaneously to the
Internet.
 Wi-Fi cards - They accept the wireless
signal and relay information. They can be
internal and external.(e.g PCMCIA Card
for Laptop and PCI Card for Desktop PC)
 Safeguards - Firewalls and anti-virus
software protect networks from uninvited
users and keep information secure.

12. WI-FI NETWORK TOPOLOGIES
Point-to-point topology
Point-to-multipoint topology
Mesh topology

13. Point-to-point TOPOLOGY
Usually very high speed and
high capacity
Requires a clear line of sight
to tower
Backbone, or backhaul
connectivity
Corporate/Business Class
service
• .

14. Point-to-multipoint
 Similar technology to point-
to-point network
 This is used to connect a LAN
in one building to a LANs in
other buildings even if the
buildings are miles apart

15. Mesh
Distributed gateway devices
Self healing network
Uses multiple radios in tight
formation
“Micro cell” concept
Relatively easy to deploy

16. WI-FI CONFIGURATIONS

17. WI-FI CONFIGURATIONS

18. WI-FI CONFIGURATIONS

19. WI-FI APPLICATIONS
• Home
• Small Businesses
• Large Corporations & Campuses
Health Care
• Wireless ISP (WISP)
• Travellers

20. WI-FI SECURITY THREATS
 Eavesdropping
 Man-in-the-middle attacks
 Denial of Service

21. EAVESDROPPING
• Easy to perform, almost impossible to detect
• By default, everything is transmitted in clear text
• Usernames, passwords, content ...
• No security offered by the transmission medium
• Different tools available on the internet
• Network sniffers, protocol analysers . . .
• Password collectors
• With the right equipment, it’s possible to
eavesdrop traffic from few kilometers away

22. MITM ATTACK
Attacker spoofes a
disassociate message from the
victim
 The victim starts to look for a
new access point, and the
attacker advertises his own AP
on a different channel, using
the real AP’s MAC address
 The attacker connects to the
real AP using victim’s MAC
address

23. DENIAL OF SERVICE
 Attack on transmission frequecy used
 Frequency jamming
 Not very technical, but works
 Attack on MAC layer
 Spoofed deauthentication / disassociation messages
 can target one specific user
 Attacks on higher layer protocol (TCP/IP protocol)
 SYN Flooding

24. ADVANTAGES
 Mobility
 Ease of Installation
 Flexibility
 Cost
 Reliability
 Security
 Use unlicensed part of the radio spectrum
 Roaming
 Speed

25. DISADVANTAGE
 To no longer The use of
WiFi band that is 2.4 GHz
does not require a license in
most countries provided that
is stays below limit of
100mW.
 And one accepts
interference from other
sources; including
interference which causes
the users devices function.

26. LIMITATIONS
 Interference
 Degradation in performance
 High power consumption
 Limited range