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Wi-Fi Technology

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

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Wi-Fi Technology

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  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 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.

  4. The Wi-Fi Technology Wi-Fi Networks use Radio Technologies to transmit & receive data at high speed . The name 802.1 comes from the IEEE committee that standardized it. • IEEE 802.11b • IEEE 802.11a • IEEE 802.11g

  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) • 100 -150 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 802.11b

  7. 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’ • 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 11 22-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 802.11 Data Link Layer The data link layer consists of two sublayers : • Logical Link Control (LLC) • Media Access Control (MAC). 802.11 uses the same 802.2 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 802.11i

  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 • www.wavewireless.com

  27. THANK YOU

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