CWNA guide to wireless LANs 2nd ch12

CWNA Guide to Wireless LANs, Second Edition Chapter Twelve Personal, Metropolitan, and Wide Area Wireless Networks Objectives • Define a wireless personal area network • List the technologies of a wireless metropolitan area network • Describe the features of a wireless wide area network • Discuss the future of wireless networking CWNA Guide to Wireless LANs, Second Edit Wireless Personal Area Networks • Wireless networks classified into four broad categories: – Wireless personal area network (WPAN): Handheld and portable devices; slow to moderate transmission speeds – Wireless local area network (WLAN): i.e., IEEE 802.11a/b/g – Wireless metropolitan area network (WMAN): Range up to 50 kilometers – Wireless wide area network (WWAN): Connects networks in different geographical areas CWNA Guide to Wireless LANs, Second Edit Wireless Personal Area Networks (continued) Figure 12-1: Wireless network distances CWNA Guide to Wireless LANs, Second Edit Wireless Personal Area Networks (continued) Figure 12-2: Point-to-point transmission CWNA Guide to Wireless LANs, Second Edit Wireless Personal Area Networks (continued) Figure 12-3: Point-to-multipoint transmission CWNA Guide to Wireless LANs, Second Edit Wireless Personal Area Networks (continued) • WPANs encompass technology designed for portable devices – PDAs, cell phones, tablet or laptop computers – Low transmission speeds • Three main categories: – IEEE 802.15 standards – Radio frequency ID (RFID) – IrDA CWNA Guide to Wireless LANs, Second Edit WPANs: IEEE 802.15.1 (Bluetooth) • Bluetooth uses short-range RF transmissions – Users can connect wirelessly to wide range of computing and telecommunications devices – Rapid and ad hoc connections between devices • 802.15.1 adapted and expanded from Bluetooth – Designed for area of about 10 meters – Rate of transmission below Mbps • Two types of 802.15.1 network topologies – Piconet – Scatternet CWNA Guide to Wireless LANs, Second Edit WPANs: IEEE 802.15.1 (continued) • Piconet: When two 802.15.1 devices come within range, automatically connect – Master: Controls wireless traffic – Slave: Takes commands from master – Piconet has one master and at least one slave • Active slave: Connected to piconet and sending transmissions • Parked slave: Connected but not actively participating CWNA Guide to Wireless LANs, Second Edit WPANs: IEEE 802.15.1 (continued) Figure 12-4: Piconet CWNA Guide to Wireless LANs, Second Edit 10 Wireless Metropolitan Area Networks: LMDS (continued) Figure 12-11: LMDS cell CWNA Guide to Wireless LANs, Second Edit 29 Wireless Metropolitan Area Networks: Multichannel Multipoint Distribution Service (MMDS) • Many similarities to LMDS – Differs in area of transmission – Higher downstream transmission, lower upstream transmission, greater range • In homes, alternative to cable modems and DSL service • For businesses, alternative to T1 or fiber optic connections • MMDS hub typically located at a very high point – On top of building, towers, mountains CWNA Guide to Wireless LANs, Second Edit 30 Wireless Metropolitan Area Networks: MMDS (continued) • Hub uses point-to-multipoint architecture – Multiplexes communications to multiple users – Tower has backhaul connection • MMDS uses cells – Single MMDS cell as large as 100 LDMS cells • Receiving end uses pizza box antenna • Advantages: – Transmission range, cell size, low vulnerability to poor weather conditions • Still requires line-of-site, not encrypted CWNA Guide to Wireless LANs, Second Edit 31 Wireless Metropolitan Area Networks: IEEE 802.16 (WiMAX) • High potential – Can connect IEEE 802.11 hotspots to Internet – Can provide alternative to cable and DSL for last mile connection – Up to 50 kilometers of linear service area range – Does not require direct line of sight – Provides shared data rates up to 70 Mbps • Uses scheduling system – Device competes once for initial network entry CWNA Guide to Wireless LANs, Second Edit 32 Wireless Metropolitan Area Networks: IEEE 802.16 (continued) • Currently addresses only devices in fixed positions – 802.16e will add mobile devices to the standard • IEEE 802.20 standard: Sets standards for mobility over large areas – Will permit users to roam at high speeds • WiMAX base stations installed by a wireless Internet service provider (wireless ISP) can send high-speed Internet connections to homes and businesses in a radius of up to 50 km (31 miles) CWNA Guide to Wireless LANs, Second Edit 33 Wireless Wide Area Networks (WWANS) • Wireless networks extending beyond 50 kilometers (31 miles) • Two primary technologies: – Digital cellular telephony – Satellites CWNA Guide to Wireless LANs, Second Edit 34 Digital Cellular Telephony • Two keys to cellular telephone networks: – Coverage area divided into cells • • • • Cell transmitter at center Mobile devices communicate with cell center via RF Transmitters connected to base station, Each base station connected to a mobile telecommunications switching office (MTSO) – Link between cellular and wired telephone network – All transmitters and cell phones operate at low power • Enables frequency reuse CWNA Guide to Wireless LANs, Second Edit 35 Digital Cellular Telephony (continued) Figure 12-13: Frequency reuse CWNA Guide to Wireless LANs, Second Edit 36 Satellites • Satellite use falls into three broad categories: – Acquire scientific data, perform research – Examine Earth • Military and weather satellites – “Reflectors” • Relay signals • Communications, navigation, broadcast CWNA Guide to Wireless LANs, Second Edit 37 Satellites (continued) • Satellite systems classified by type of orbit: – Low earth orbiting (LEO): Small area of earth coverage • Over 225 satellites needed for total coverage of earth • Must travel very fast – Medium earth orbiting (MEO): Larger area of coverage than LEO • Do not need to travel as fast – Geosynchronous earth orbiting (GEO): orbit matches earth’s rotation • “Fixed” position • Very large coverage area CWNA Guide to Wireless LANs, Second Edit 38 Satellites (continued) Figure 12-14: LEO coverage area CWNA Guide to Wireless LANs, Second Edit 39 The Future of Wireless Networks • IEEE 802.11 subcommittees currently at work: – 802.11d: Supplementary to 802.11 MAC layer • Promote worldwide use of 802.11 WLANs – 802.11f: Inter-Access Point Protocol (IAPP) • Will assist with faster handoff from one AP to another – 802.11h: Supplement to MAC layer to comply with European regulations for GHz WLANs – 802.11j: Incorporates Japanese regulatory extensions to 802.11a standard – 802.11s: Defines a mesh wireless network • Devices configure themselves and are intelligent CWNA Guide to Wireless LANs, Second Edit 40 Summary • WPANs encompass technology that is designed for portable devices, typically PDAs, cell phones, and tablet or laptop computers at transmission speeds lower than the other types of networks • The IEEE 802.15 standards address wireless personal area networks • RFID is not a standard but is a technology that uses RF tags to transmit information • IrDA technology uses infrared transmissions to transmit data at speeds from 9,600 bps to 16 Mbps CWNA Guide to Wireless LANs, Second Edit 41 Summary (continued) • FSO is an optical, wireless, point-to-point wireless metropolitan area network technology • LMDS can provide a wide variety of wireless services, including high-speed Internet access, real-time multimedia file transfer, remote access to local area networks, interactive video, video-ondemand, video conferencing, and telephone • MMDS has many of similarities to LMDS, yet has a longer distance range CWNA Guide to Wireless LANs, Second Edit 42 Summary (continued) • The IEEE 802.16 (WiMAX) standard holds great promise for providing higher throughput rates for fixed location and mobile users • Wireless wide area network (WWAN) technology encompasses digital cellular telephony and satellite • The future of wireless networks is hard to predict, but most experts agree that wireless networks will be faster, more global, and easier to use in the years ahead CWNA Guide to Wireless LANs, Second Edit 43 ... geographical areas CWNA Guide to Wireless LANs, Second Edit Wireless Personal Area Networks (continued) Figure 12-1: Wireless network distances CWNA Guide to Wireless LANs, Second Edit Wireless Personal... 12-2: Point -to- point transmission CWNA Guide to Wireless LANs, Second Edit Wireless Personal Area Networks (continued) Figure 12-3: Point -to- multipoint transmission CWNA Guide to Wireless LANs, Second... and rainfall CWNA Guide to Wireless LANs, Second Edit 28 Wireless Metropolitan Area Networks: LMDS (continued) Figure 12-11: LMDS cell CWNA Guide to Wireless LANs, Second Edit 29 Wireless Metropolitan