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Unformatted text preview: Chapter 8 Wireless Networks II Wireless Networks II o WLAN Standards FCC created unlicensed garbage bands 1985 802 . 11 ( wifi ) first standardized in 1997 7 year process o Evolved rapidly : 2 Mbps to 300 Mbps data rate o Key Markets enterprise, consumer, service provider Cisco made 1.1 billion dollars selling this o 802.11 Operation Access point translates between radio transmission and Ethernet Connects access layer switch to tiers/router Bridges b/w wireless and Ethernet o Organizations provide coverage through buildings or campuses by access points 2500 access points at Syracuse o Speed distance o Up to 300 Mbps usually 10-100 Mbps o Typical car- radius of 30 to 50 meters o Devices=Router with access points : PC Card Wireless NIC Internal Wireless NIC External Wireless NIC with USB Connector o Frequency Spectrum All possible frequencies (0hz to infinity) Divided into blocks source bands Source bands : dedicated into individual services Service Bands : divided into channels o Signal sent in a single channel o Signals in different channels do not interfere o Channel Bandwidth Highest frequency in a channel minus the lowest Ex: 88.0 MHz to 88.2 MHz = .2 MHz bandwidth Shannon Equation C=B [log 2 (1 + s/n) ] o Golden Zone Most radio techs operate in this...
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- Spring '09