Wi-Fi Technology By: Mohamed Hassan Ali May, 2005

Wi-Fi Technology

By: Mohamed Hassan Ali

May, 2005

Topics

• Wi-Fi Products• Wi-Fi IEEE Standards• Wi-Fi Development Roadmap• Wireless Network Modes

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Wi-Fi Products

• Wireless router (built-in modem)• Access Points• Client Adapters:– built-in– USB adapter– PCI wireless card– PCMCIA wireless card

• Antennas

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Wi-Fi Products

• Wireless LAN Controllers• Wireless Integrated Switches and Routers• Wireless IP Telephony• Wireless Display• Wireless Gaming Console

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Wireless router

Cisco-Linksys WRT54GL Wireless-G Broadband Router

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Wireless Access Points

Cisco-Linksys WAP54G Wireless-G Access Point04/10/23 6Wi-Fi Technology

Client Adapters

2000mW 2W 802.11g/n High Gain USB Wireless G / N Long-Rang WiFi Network Adapter

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Wireless Antennas & Range Expander

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Wireless LAN Controllers

Cisco Catalyst 6500 Series/7600 Series Wireless Services Module (WiSM)

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Wireless Integrated Switches and Routers

Cisco 2800 Series Integrated Services Routers

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Wireless IP Telephony

Cisco Unified IP Phone 7900 Series

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Wireless Display

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Wi-Fi IEEE StandardsCreation

Year Bandwidth Radio Frequency

Indoor Range[meter]

Outdoor Range[meter]

802.11 Jun 1997 2 Mbps 2.4 GHz 20 330

802.11a Sep 1999 up to 54 Mbps

5 GHz 35 390

802.11b Sep 1999 up to 11 Mbps

2.4 GHz 38 460

802.11g Jun 2003 up to54 Mbps

2.4 GHz 38 460

802.11n Oct 2009 up to72.2 Mbps

up to150 Mbps

2.4 GHz

5 GHz70 820

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Wi-Fi Development Roadmap

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Wireless Network Modes

• Infrastructure Mode• Ad-Hoc Mode• Bridging Mode• Repeater Mode

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Infrastructure Mode

• Infrastructure mode wireless networking bridges (joins) a wireless network to a wired Ethernet network.

• Infrastructure mode wireless also supports central connection points for WLAN clients.

• Infrastructure mode networks offer the advantage of scalability, centralized security management and improved reach.

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Infrastructure Wireless Network Diagram [Wireless Router]

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Infrastructure Wireless Network Diagram [Wired Router + AP]

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Ad-Hoc Mode

• Ad-Hoc mode is a method for wireless devices to directly communicate with each other.

• Operating in ad-hoc mode allows all wireless devices within range of each other to discover and communicate in peer-to-peer fashion without involving central access points

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Ad-Hoc Wireless Network Diagram

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Bridging Mode

• Bridging mode allows two or more wireless access points (APs) to communicate with each for the purpose of joining multiple LANs.

• Wireless bridges support:– Point-to-Point– Point-to-Multipoint

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Bridging Mode

• Bridge modes:– Bridge-only– Bridge & Access Point

• APs in bridging mode discover each other via Media Access Control (MAC) addresses that must be set as configuration parameters.

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Bridging Wireless Network Diagram

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Point-to-Point and Point-to-Multipoint

Point-to-Point

Point-to-Multipoint

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Repeater Mode

• Repeater mode is a variation on bridging. Rather than join multiple LANs, repeater mode is intended mainly to increase the range of a single wireless LAN by extending the same wireless signal.

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Repeater Wireless Network Diagram

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Positioning Guidelines

1. don't settle prematurely on a location2. install the wireless access point or router in a

central location3. avoid physical obstructions4. Avoid reflective surface5. away from other home appliances that send

wireless signals6. install the unit away from electrical equipment7. install a Wi-Fi repeater

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Wi-Fi Authentication & Encryption

Authentication EncryptionOpen WEP Encryption [64 & 128 bits]

Passphrase + Network KeyShared802.1x NONEWPA

• TKIP• AES• TKIP+AES

WPA/PSKWPA2WPA2/PSKMixed WPA2/WPAMixed WPA2/WPA -PSK

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Thank YouThank You

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