tailieunhanh - Lecture Business data communications and networking (8th edition): Chapter 7 - Jerry Fitzgerald, Alan Dennis

Chapter 7 - Wireless local area networks. In this chapter, the following content will be discussed: Introduction, IEEE , IEEE , IEEE , bluetooth, best practice WLAN design, improving WLAN performance. | Business Data Communications and Networking 8th Edition Jerry Fitzgerald and Alan Dennis John Wiley & Sons, Inc Prof. M. Ulema Manhattan College Computer Information Systems 7 - Copyright 2005 John Wiley & Sons, Inc Chapter 7 Wireless Local Area Networks 7 - Copyright 2005 John Wiley & Sons, Inc Outline Introduction IEEE IEEE IEEE Bluetooth Best practice WLAN Design Improving WLAN Performance 7 - Copyright 2005 John Wiley & Sons, Inc Wireless LANs (WLANs) Use radio or infrared frequencies to transmit signals through the air (instead of cables) Basic Categories Use of Radio frequencies (FOCUS of this chapter) family of standards (aka, Wi-Fi) Use of Infrared frequencies (Optical transmission) Wi-Fi grown in popularity Eliminates cabling Facilitates network access from a variety of locations Airports, cafes, restaurants, etc., Facilitates for mobile workers (as in a hospital) 7 - Copyright 2005 John Wiley & Sons, Inc Principal WLANs . | Business Data Communications and Networking 8th Edition Jerry Fitzgerald and Alan Dennis John Wiley & Sons, Inc Prof. M. Ulema Manhattan College Computer Information Systems 7 - Copyright 2005 John Wiley & Sons, Inc Chapter 7 Wireless Local Area Networks 7 - Copyright 2005 John Wiley & Sons, Inc Outline Introduction IEEE IEEE IEEE Bluetooth Best practice WLAN Design Improving WLAN Performance 7 - Copyright 2005 John Wiley & Sons, Inc Wireless LANs (WLANs) Use radio or infrared frequencies to transmit signals through the air (instead of cables) Basic Categories Use of Radio frequencies (FOCUS of this chapter) family of standards (aka, Wi-Fi) Use of Infrared frequencies (Optical transmission) Wi-Fi grown in popularity Eliminates cabling Facilitates network access from a variety of locations Airports, cafes, restaurants, etc., Facilitates for mobile workers (as in a hospital) 7 - Copyright 2005 John Wiley & Sons, Inc Principal WLANs Technologies IEEE Standardization started after .11a, but finished before IEEE First attempt to standardization of WLANs; more complicated than .11b IEEE Bluetooth Also an IEEE standard 7 - Copyright 2005 John Wiley & Sons, Inc IEEE Reuses many Ethernet components Designed to connect easily to Ethernet ., wireless Ethernet Also called Wi-Fi Marketing ploy; sounds like Hi-Fi Versions of .11b Direct Sequence Spread Spectrum (DSSS) Focus of this chapter (more popular) Frequency Hopping Spread Spectrum (FHSS) 7 - Copyright 2005 John Wiley & Sons, Inc Versions of IEEE Direct Sequence Spread Spectrum (DSSS) Uses the entire frequency band to transmit information Capable of data rates of up to 11 Mbps Fallback rates: , 2 and 1 Mbps. (Used when interference or congestion occurs) Dominates market place, because faster Frequency Hopping Spread Spectrum (FHSS) Divides the frequency band into a series of channels Then changes its frequency .