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Wi-Fi 802.11 WLAN

Wi-Fi 802.11 WLAN. Romney Bake Brian Peterson Clay Stephens Michael Hatheway. Outline. Introduction Topology Advantages/Disadvantages Hardware A, B, G, N Comparison Media Access Controls/Data Transmission Security Types Router Configuration Questions. Introduction & History.

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Wi-Fi 802.11 WLAN

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  1. Wi-Fi 802.11WLAN Romney Bake Brian Peterson Clay Stephens Michael Hatheway

  2. Outline • Introduction • Topology • Advantages/Disadvantages • Hardware • A, B, G, N Comparison • Media Access Controls/Data Transmission • Security Types • Router Configuration • Questions

  3. Introduction & History • Wireless connections were originally developed for mobile computing devices, such as laptops, but is now increasingly used for more services, including Internet and VoIP phone access and basic connectivity of consumer electronics such as televisions and DVD players. • First Wireless LAN developed in 1971, called ALOHANET.

  4. Topology Internet

  5. Advantages Advantages • No cables (Outdoor uses) • Mobility • Widely available products • Global set of standards • Available in more than 300,000 hot spots • WPA and WPA2 securities • Cheaper/Comparable prices

  6. Disadvantages • Drains batteries on laptops • Security issues • Default settings for access points and routers • Potential interoperability between brands • Often slower than wired connections • Limited range

  7. Hardware Access Point (AP) • Connects a group of wireless devices to an adjacent wired LAN • Relays data between connected wireless devices in addition to a (usually) single connected wired device

  8. Wireless Adapter (WNIC) • Allows a device to connect to a wireless network • Connects by either PCI, USB, PCMCIA

  9. Wireless Router • Allows wired and wireless ethernet LAN devices to connect to a (usually) single WAN device such as cable modem or DSL modem • allows all three devices (mainly the access point and router) to be configured through one central utility

  10. Range Extender • Extends the range of an existing wireless network • Allows signal area to reach around barriers such as those created in L-shaped corridors • Increase in latency

  11. 802.11a, b, g, n

  12. Media Access Control • Uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA), similar to CSMA/CD in wired Ethernet • Computers listen before transmitting, if no one else is transmitting, they transmit

  13. Data Transmission Distributed Coordination Function • Relies on computers to physically listen before transmitting • Stop and Wait ARQ Point Coordination Function • Computer must send Request To Transmit to Access Point first • The Clear To Transmit is granted for requesting computer for specific time period on the circuit • Works well with high traffic networks

  14. Security Types Service Set Identifier (SSID) • Code attached to all packets on a wireless network to identify each packet as part of that network • Code is a case sensitive text string which consists of a maximum of 32 alphanumeric characters • Minimum security

  15. Wired Equivalent Privacy (WEP) • Provide comparable confidentiality to a traditional wired network • WEP key can be cracked with readily available software in two minutes or less • Easy to share key for access

  16. Extensible Authentication Protocol (EAP) • Generates WEP keys automatically • User login to server • After login sever will generate WEP key for the session • Easy to break by professional hackers

  17. Wi-Fi Protected Access (WPA and WPA2) • Intended as an intermediate measure to take the place of WEP while 802.11i was prepared • Designed to work with all wireless network interface cards, but not necessarily with first generation wireless access points • WPA2 implements the full standard, but will not work with some older network cards • Not selected by default

  18. Questions ?

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