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CWNA Guide to Wireless LANs, Second Edition Chapter Twelve Personal, Metropolitan, and Wide Area Wireless Networks.

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Presentation on theme: "CWNA Guide to Wireless LANs, Second Edition Chapter Twelve Personal, Metropolitan, and Wide Area Wireless Networks."— Presentation transcript:

1 CWNA Guide to Wireless LANs, Second Edition Chapter Twelve Personal, Metropolitan, and Wide Area Wireless Networks

2 CWNA Guide to Wireless LANs, Second Edition2 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

3 CWNA Guide to Wireless LANs, Second Edition3 Wireless Personal Area Networks Wireless networks classified into four broad categories: –Wireless personal area network (WPAN): Hand- held and portable devices; slow to moderate transmission speeds –Wireless local area network (WLAN): i.e., IEEE a/b/g –Wireless metropolitan area network (WMAN): Range up to 50 kilometers –Wireless wide area network (WWAN): Connects networks in different geographical areas

4 CWNA Guide to Wireless LANs, Second Edition4 Wireless Personal Area Networks (continued) Figure 12-1: Wireless network distances

5 CWNA Guide to Wireless LANs, Second Edition5 Wireless Personal Area Networks (continued) Figure 12-2: Point-to-point transmission

6 CWNA Guide to Wireless LANs, Second Edition6 Wireless Personal Area Networks (continued) Figure 12-3: Point-to-multipoint transmission

7 CWNA Guide to Wireless LANs, Second Edition7 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 standards –Radio frequency ID (RFID) –IrDA

8 CWNA Guide to Wireless LANs, Second Edition8 WPANs: IEEE (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 adapted and expanded from Bluetooth –Designed for area of about 10 meters –Rate of transmission below 1 Mbps Two types of network topologies –Piconet –Scatternet

9 CWNA Guide to Wireless LANs, Second Edition9 WPANs: IEEE (continued) Piconet: When two 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

10 CWNA Guide to Wireless LANs, Second Edition10 WPANs: IEEE (continued) Figure 12-4: Piconet

11 CWNA Guide to Wireless LANs, Second Edition11 WPANs: IEEE (continued) Figure 12-5: Slave device detected by a master device

12 CWNA Guide to Wireless LANs, Second Edition12 WPANs: IEEE (continued) Devices in piconet can be in one of five modes: –Standby: Waiting to join a piconet –Inquire: Device looking for devices to connect to –Page: Master device asking to connect to specific slave –Connected: Active slave or master –Park/Hold: Part of piconet but in low-power state Scatternet: Group of piconets in which connections exist between different piconets uses FHSS

13 CWNA Guide to Wireless LANs, Second Edition13 WPANs: IEEE (continued) Figure 12-6: Scatternet

14 CWNA Guide to Wireless LANs, Second Edition14 WPANs: IEEE (continued) Table 12-1: Comparison of speed

15 CWNA Guide to Wireless LANs, Second Edition15 WPANs: IEEE Created in response to limitations of –High-rate WPANs Two main applications: –Video and audio distribution for home entertainment systems High-speed digital video transfer High-density MPEG2 transfer between video players/gateways and multiple HD displays Home theater PC to LCD projector Interactive video gaming –High speed data transfer

16 CWNA Guide to Wireless LANs, Second Edition16 WPANs: IEEE (continued) Differences between and –Quality of Service (QoS) –Security –High data rates –Spectrum utilization –Coexistence Table 12-2: IEEE security modes

17 CWNA Guide to Wireless LANs, Second Edition17 WPANs: IEEE (continued) a: Will support data transfers up to 110 Mbps between max of 245 devices at 10 meters –Ultrawideband (UWB) –Intended to compete with USB 2.0 and FireWire IEEE b task group working on improving implementation and interoperability of IEEE c task group developing alternative physical layer standard that could increase speeds up to 2 Gbps

18 CWNA Guide to Wireless LANs, Second Edition18 WPANs: IEEE Sometimes preferable to have low-speed, low- power wireless devices –Size can be dramatically reduced IEEE standard addresses requirements for RF transmissions requiring low power consumption and cost Table 12-3: IEEE data rates and frequencies

19 CWNA Guide to Wireless LANs, Second Edition19 WPANs: IEEE (continued) ZigBee Alliance: Industry consortium that promotes standard Figure 12-7: ZigBee and IEEE

20 CWNA Guide to Wireless LANs, Second Edition20 WPANs: Radio Frequency ID (RFID) Figure 12-8: RFID tag

21 CWNA Guide to Wireless LANs, Second Edition21 WPANs: Radio Frequency ID (continued) Passive RFID tags: No power supply –Can be very small –Limited amount of information transmitted Active RFID tags: Must have power source –Longer ranges/larger memories than passive tags Table 12-4: RFID tags

22 CWNA Guide to Wireless LANs, Second Edition22 WPANs: IrDA Infrared Data Association IrDA specifications include standards for physical devices and network protocols they use to communicate Devices communicate using infrared light-emitting diodes –Recessed into device –Many design considerations affect IrDA performance

23 CWNA Guide to Wireless LANs, Second Edition23 WPANs: IrDA (continued) Figure 12-9: IrDA diodes in device

24 CWNA Guide to Wireless LANs, Second Edition24 WPANs: IrDA (continued) IrDA drawbacks: –Designed to work like standard serial port on a personal computer, which is seldom used today –Cannot send and receive simultaneously –Strong ambient light can negatively impact transmissions –Angle and distance limitation between communicating devices

25 CWNA Guide to Wireless LANs, Second Edition25 Wireless Metropolitan Area Networks Cover an area of up to 50 kilometers (31 miles) Used for two primary reasons: –Alternative to an organization’s wired backhaul connection i.e., T1, T3, T4 lines –Fiber Optics Very expensive to install backhaul connections Often less expensive to use a WMAN to link remote sites

26 CWNA Guide to Wireless LANs, Second Edition26 Wireless Metropolitan Area Networks (continued) Used for two primary reasons (continued): –Overcome last mile connection Connection that begins at a fast Internet service provider, goes through local neighborhood, and ends at the home or office Slower-speed connection –Bottleneck

27 CWNA Guide to Wireless LANs, Second Edition27 Wireless Metropolitan Area Networks: Free Space Optics Optical, wireless, point-to-point, line-of-sight wireless technology –Able to transmit at speed comparable to Fiber Optics –Transmissions sent by low-powered IR beams Advantages compared to fiber optic and RF: –Lower installation costs –Faster installation –Scaling transmission speed –Good security Atmospheric conditions can affect transmission

28 CWNA Guide to Wireless LANs, Second Edition28 Wireless Metropolitan Area Networks: Local Multipoint Distribution Service (LMDS) LMDS provides wide variety of wireless services –High-frequency, low-powered RF waves have limited range –Point-to-multipoint signal transmission Signals transmitted back are point-to-point –Voice, data, Internet, and video traffic –Local carrier determines services offered LMDS network is composed of cells –Cell size affected by line of site, antenna height, overlapping cells, and rainfall

29 CWNA Guide to Wireless LANs, Second Edition29 Wireless Metropolitan Area Networks: LMDS (continued) Figure 12-11: LMDS cell

30 CWNA Guide to Wireless LANs, Second Edition30 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

31 CWNA Guide to Wireless LANs, Second Edition31 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

32 CWNA Guide to Wireless LANs, Second Edition32 Wireless Metropolitan Area Networks: IEEE (WiMAX) High potential –Can connect IEEE 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

33 CWNA Guide to Wireless LANs, Second Edition33 Wireless Metropolitan Area Networks: IEEE (continued) Currently addresses only devices in fixed positions –802.16e will add mobile devices to the standard IEEE 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)

34 CWNA Guide to Wireless LANs, Second Edition34 Wireless Wide Area Networks (WWANS) Wireless networks extending beyond 50 kilometers (31 miles) Two primary technologies: –Digital cellular telephony –Satellites

35 CWNA Guide to Wireless LANs, Second Edition35 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

36 CWNA Guide to Wireless LANs, Second Edition36 Digital Cellular Telephony (continued) Figure 12-13: Frequency reuse

37 CWNA Guide to Wireless LANs, Second Edition37 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

38 CWNA Guide to Wireless LANs, Second Edition38 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

39 CWNA Guide to Wireless LANs, Second Edition39 Satellites (continued) Figure 12-14: LEO coverage area

40 CWNA Guide to Wireless LANs, Second Edition40 The Future of Wireless Networks IEEE subcommittees currently at work: –802.11d: Supplementary to MAC layer Promote worldwide use of 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 5 GHz WLANs –802.11j: Incorporates Japanese regulatory extensions to a standard –802.11s: Defines a mesh wireless network Devices configure themselves and are intelligent

41 CWNA Guide to Wireless LANs, Second Edition41 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 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

42 CWNA Guide to Wireless LANs, Second Edition42 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-on- demand, video conferencing, and telephone MMDS has many of similarities to LMDS, yet has a longer distance range

43 CWNA Guide to Wireless LANs, Second Edition43 Summary (continued) The IEEE (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


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