Download Wi-Fi Technology

Wi-Fi Technology
By Marc Bailey
What is Wi-Fi?
• Wi-Fi or Wireless Fidelity is a wireless
technolgy owned by the Wi-Fi Alliance
(formed in 1999)
• Goal: Improve the use and exchange of
information on wireless local area network
products
• Uses the Institute of Electrical and Electronics
Engineers (IEEE) 802.11 standards
802.11 Standards
• 802.11a
- High frequency
- More “flexible” and “reliable”
- (Tomsho, Tittel, & Johnson)
- Problematic with upgrades from the 802.11b
standard
• 802.11b
- Most common
- Longest in use
802.11 Standards (cont.)
• 802.11g
- High frequency
- Backwards compatible with 802.11b
How does Wi-Fi Work?
• Rather than using wires to connect, Wi-Fi
uses radio waves as the medium
• Extention to Ethernet
• Range is several feet to serveral hundred feet
(depending on environment and interference)
• OSI Model: Physical Layer
Using Wi-Fi
• Devices: PCs, game consoles, cell phones,
mp3 players, and PDAs
• Network Design: Hotspots and Mesh
Networks
• Peer-to-peer: Consumer electronics and
gaming
• Who uses it?: Consumers with Wi-Fi
technology and businesses
Hotspots
• Localized wireless access areas
• Various locations: Train stations, airports,
coffee shops, universities, etc.
• Commerical Hotspots
- Portals for authentication and payment
- Payment options (credit card, PayPal, etc.)
- Smaller buisnesses may offer free service
Examples: Hotels and small airports
Hotspots (cont.)
• Free Hotspots
- Open public network with a Wi-Fi router
- Can be a closed public network with the
right software that protects and manages the
network
• A security issue especially when dealing with
an unsecured hotspot
Wi-Fi Pros
• No wires for machines
• Good for places that are difficult to get cables
into
• Drops in price
• Interoperable: Works anywhere a Wi-Fi
connection is available since Wi-Fi is a global
set of standards
Wi-Fi Cons
• Wi-Fi channels used not the same worldwide
• High power consumption
• Limited range (but can be improved by
antennas)
• Wi-Fi pollution: High number of access points
in one area can lead to interference
Security Options
• Service Set Identifier (SSID)
- Uniquely identifies the wireless LAN with a
configured alphanumeric label.
• Wired Equivalency Protocol (WEP)
- A widely available data encryption. It does
have the chance of being cracked by a
motivated attacker.
• Wi-Fi Protocol Access (WPA)
- An upgrade over WEP in terms of security.
The data encryption is harder to crack due to
the key automatically changing periodically.
Security Options (cont.)
• 802.11i or WPA2
- Similar to WPA, but incorporates more
advanced data encryption.
• Mac Address Filtering
- Limits which computers can use the network
based on their MAC addresses. Not practical
for large networks.
Security: Hotspots
• Most are unsecured
• Even though it is costly, Virtual Private
Networks (VPN) can be used
• Some companies provide downloadable WPA
support
• Indentity theives and other criminals can set
up a free public hotspot to steal valuable
information. Commonly known as a
“poisioned hotspot”
Video
http://www.youtube.com/watch?v=n2WSg2ibtHc
References
• Guide to Networking Essentials - Fifth Edition
by Greg Tomsho, Ed Tittel, & David Johnson
• http://www.wi-fi.org/
• http://en.wikipedia.org/wiki/Wi-Fi