This document discusses Wi-Fi technology, including its history and standards, how Wi-Fi networks work, common network topologies, applications, security techniques and advantages/disadvantages. It introduces Wi-Fi as a wireless alternative to wired networks that uses radio technologies like 802.11b, 802.11a and 802.11g to transmit data at high speeds. Key components of a Wi-Fi network include access points and Wi-Fi cards. [/SUMMARY]

1. Wi-Fi TECHNOLOGY
BY
TEJASRI

2. A New Paradigm of Wireless Technology

3. This Paper Tells About
• Introduction
• Wi-Fi Technologies
• Wi-Fi Network Elements
• How a Wi-Fi Network Works
• Wi-Fi Network Topologies
• Wi-Fi Applications
• Wi-Fi Configurations
• Wi-Fi Security
• Advantages/ Disadvantages of Wi-Fi

4. Introduction
• Wireless Technology is an alternative to Wired
Technology, which 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.

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. Comparisons Of Wi-Fi Flavours
802.11b 802.11a 802.11g
In 1999
2.4GHz
In 2001
5GHz
In 2003
2.4GHz
11Mbps 54Mbps 54Mbps
30-100m 100-300m 100-300m

7. 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.

8. How a Wi-Fi Network Works
• Basic concept is same as Walkie talkies.
• A Wi-Fi hotspot is created by installing an access point to
an internet connection.
• An access point acts as a base station.
• When Wi-Fi enabled device encounters a hotspot the
device can then connect to that network wirelessly.
• A single access point can support up to 30 users and
can function within a range of 100 – 150 feet indoors and
up to 300 feet outdoors.
• Many access points can be connected to each other via
Ethernet cables to create a single large network.

9. How a Wi-Fi Network Works
» A computer's wireless
adapter translates data into
a radio signal and transmits
it using an antenna.
» A wireless router receives
the signal and decodes it.
» The router sends the
information to the Internet
using a physical, wired
Ethernet connection.

10. Wi-Fi Network Topologies
• AP-based topology (Infrastructure Mode)
• Peer-to-peer topology
• Point-to-multipoint bridge topology

11. AP-based topology
• The client communicate 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.

12. 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.

13. Point-to-multipoint bridge topology
This is used to connect a LAN in one building to a LANs
in other 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.

14. Wi-Fi Applications
• Home
• Small Businesses or SOHO
• Large Corporations & Campuses
• Health Care
• Wireless ISP (WISP)
• Travellers

15. Wi-Fi Security
The requirements for Wi-Fi network security
can be broken down into two primary
components:
• Authentication
 User Authentication
 Server Authentication
• Privacy

16. Wi-Fi Security Techniques
• Service Set Identifier (SSID)
• Wired Equivalent Privacy (WEP)
• 802.1X Access Control
• Wireless Protected Access (WPA)
• IEEE 802.11i

17. Service Set Identifier (SSID)
• SSID is used to identify an 802.11 network
• It can be pre-configured or advertised in the
name of provider
• It is transmitted in clear text
• Provide very little security

18. Wired Equivalent Privacy (WEP)
• Uses RC4 encryption with pre-shared keys and 24 bit
initialization vectors (IV)
• Key schedule is generated by concatenating the
shared secret key with a random generated 24-bit IV
• 32 bit ICV (Integrity check value)
• No. of bits in keyschedule is equal to sum of length of
the plaintext and ICV
• Security Issue with WEP
• Short IV
• Static key

19. 802.1x Access Control

20. Wireless Protected Access (WPA)
• WPA is a specification of standard based, interoperable
security enhancements that strongly increase the level of data
protection and access control for existing and future wireless
LAN system.
• User Authentication
• 802.1x
• TKIP (Temporal Key Integrity Protocol) encryption
• RC4, dynamic encryption keys (session based)
• 48 bit IV
• Fixes all issues found from WEP
• Uses Message Integrity Code (MIC)
– Ensures data integrity
• Old hardware should be upgradeable to WPA

21. 802.11i
• Provides standard for WLAN security
• Authentication
• 802.1x
• Data encryption
• AES protocol is used
• Secure fast handoff-This allow roaming between
APs without requiring client to fully reauthenticate to
every AP.
• Will require new hardware

22. Advantages
• Mobility
• Ease of Installation
• Flexibility
• Cost
• Reliability
• Security
• Roaming
• Speed

23. Limitations
• Interference
• Degradation in performance
• High power consumption
• Limited range

24. Conclusion
• In the past, internet is luxury but now a days it
is need.
• So that for our requirements it’s necessity to
develop further technologies with low cost &
high speed of data transmission.

25. “Things that thinks …
don’t make sense unless they link.”

26. QUERIES ?
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