1. Wi-Fi Technology
ARTI J JANSARI
M.E.(C.S.E.):-1ST (E.C.)

2. CONTENTS Introduction Wi-Fi Technologies Wi-Fi Architecture
Wi-Fi Network Elements
How a Wi-Fi Network Works
Wi-Fi Network Topologies
Applications of Wi-Fi
Wi-Fi Security
Advantages/ Disadvantages of Wi-Fi

3. 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 communications standard for Wireless Local Area Networks (WLANs).
Wi-Fi Network connect computers to each other, to the internet and to the wired network.

4. The Wi-Fi Technology
Wi-Fi Networks use Radio Technologies to transmit & receive data at high speed
. The name comes from the IEEE committee that standardized it.
IEEE b
IEEE a
IEEE g

5. 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)
feet range
Most popular, Least Expensive
Interference from mobile phones and Bluetooth devices which can reduce the transmission speed.

6. 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 b

7. IEEE g
Introduced in 2003
Combine the feature of both standards (a,b)
feet range
54 Mbps Speed
2.4 GHz radio frequencies
Compatible with ‘b’
Use OFDM Technology

8. 802.11 Physical Layer There are three sub layers in physical layer:
Direct Sequence Spread Spectrum (DSSS)
Frequency Hoping Spread Spectrum (FHSS)
Diffused Infrared (DFIR) - Wide angle

9. DSSS
Direct sequence signaling technique divides the 2.4 GHz band into MHz channels. Adjacent channels overlap one another partially, with three of the 11 being completely non-overlapping. Data is sent across one of these 22 MHz channels without hopping to other channels.

10. IEEE Data Link Layer
The data link layer consists of two sublayers :
Logical Link Control (LLC)
Media Access Control (MAC).
uses the same LLC and 48-bit addressing as other 802 LANs, allowing for very simple bridging from wireless to IEEE wired networks, but the MAC is unique to WLANs.

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 – 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.

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 CONFIGURATION

18. Wi-Fi CONFIGURATION

19. Wi-Fi CONFIGARATION

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

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

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

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

24. LIMITATION Interference Degradation in performance
High power consumption
Limited range

25. CONCLUSION
For now Wi-Fi provides broad band internet access to specially outfitted PCs and Laptops. But in future may be hotspots be wireless.
By Wi-Fi our time and money are saved.
The technologies have help Wi-Fi “Hotspots are becoming more popular throught urban envirnment.”

26. REFERENCE www.Wi-Fitechnology.com www.webopedia.com

27. THANK YOU