1. Wi-Fi Technologies

2. Wi-Fi
(Wireless-Fidelity) Technologies

3. Wi-Fi Tech. Agenda
 Introduction
 Purpose
 Wi-Fi Alliance
 The Wi-Fi Technology
 Elements of a WI-FI Network
 How a Wi-Fi Network Works
 Wi-Fi Network Topologies
 Wi-Fi Configurations
 Wi-Fi Applications
 Wi-Fi Security
 Authentication
 Advantages & Disadvantages

4. Intro.
• 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.
 Wi-Fi works on physical and data link layer.

5. Purpose
The purpose of Wi-Fi is to hide complexity
by enabling wireless access to applications
and data, media and streams.
The main aims of Wi-Fi are the following:
 make access to information easier
 ensure compatibility and co-existence of
devices
 eliminate cabling and wiring
 eliminate switches, adapters, plugs, pins
and connectors

6. Wi-Fi Alliance
 The Alliance promotes standards with the aim of
improving the interoperability of wireless local
area network products based on the IEEE 802.11
standards. The Wi-Fi Alliance, a consortium of
separate and independent companies, agrees on
a set of common interoperable products based on
the family of IEEE 802.11 standards.The Wi-Fi
Alliance certifies products via a set of defined
test-procedures to establish interoperability. The
Wi-Fi Alliance initially complicated matters by
stating that it actually stood for "Wireless
Fidelity", as with the advertising slogan"The
Standard for Wireless Fidelity", but later removed
the phrase from their marketing.

7. 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
• IEEE 802.11n

8. 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.

9. 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

10. 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’

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. 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 up to 300
feet.
• Many access points can be connected to each
other via Ethernet cables to create a single large
network.

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

14. 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.

15. 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.

16. 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.

17. Wi-Fi Configurations
Wi-Fi is composed of three main sectors:
 Home (individual residences and
apartment buildings)
 Public (Round about 70,000 “hotspots”
through out the world.)
 Enterprise (corporations, universities,
office parks)

18. Wi-Fi Configurations

19. Wi-Fi Configurations

20. Wi-Fi Configurations

22. Employee Access

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

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

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

26. Authentication
• Authentication Server is used
• Username and password
• Risk:
• Data (username & password) send before
secure channel established
• Solution
• Establishing a encrypted channel before
sending username and password

27. Advantages
• Mobility
• Ease of Installation
• Flexibility
• Cost
• Reliability
• Security
• Use unlicensed part of the radio spectrum
• Roaming
• Speed

28. Limitations OR Disadvantages
• Interference
• Degradation in performance
• High power consumption
• Limited range