List of Figures

Chapter 1: Introduction

Figure 1-1: The three components of a telephone network— access, switching, and transport

Figure 1-2: The relationship between Class 4 and Class 5 switches.

Figure 1-3: An overview of a broadband wireless alternative to the PSTN

Chapter 2: How Does 802.11 Work?

Figure 2-1: A WLAN on an enterprise network

Figure 2-2: Digital modulation of data with PN sequence

Figure 2-3: The spreading of spectrum for transmission in DSSS or FHSS

Figure 2-4: IEEE 802.11 standards mapped to the OSI reference model

Figure 2-5: CSMA/CA backoff algorithm

Figure 2-6: Wireless ad hoc network

Figure 2-7: Wireless BSS

Figure 2-8: 802.11 ESS

Chapter 3: Range is Not an Issue

Figure 3-1: Radiated power and reach of antennas— omnidirectional and directional

Figure 3-2: The range of 802.11b exceeds 20 miles.

Figure 3-3: Covering a metro area with WMANs, WWANs, WLANs, and WPANs

Figure 3-4: A WMAN

Figure 3-5: CPNs—note that like a SONET ring, data flow reverses itself in case of disruption in the network.

Figure 3-6: An ad hoc peer-to-peer network

Figure 3-7: Extending the range of wireless data transmission via architecture

Chapter 4: Security and 802.11

Figure 4-1: Normal flow

Figure 4-2: Interception in a network

Figure 4-3: The creation of ciphertext in WEP

Figure 4-4: Fabrication in a network

Figure 4-5: Open system authentication in an 802.11 network

Figure 4-6: Shared key authentication in an 802.11 network

Figure 4-7: Modification attack in an 802.11 network

Figure 4-8: Replay attack on a network

Figure 4-9: An example of a reaction attack

Figure 4-10: An example of interruption

Figure 4-11: An example of repudiation

Figure 4-12: The WLAN architecture

Figure 4-13: A wireless authentication firewall protects the LAN

Figure 4-14: 802.1x authentication

Figure 4-15: 802.1x protocol stack

Figure 4-16: A WLAN with VPN

Figure 4-17: A WLAN with VPN using remote network access

Figure 4-18: Kerberos authentication flow

Chapter 5: Interference and Quality of Service (QoS) on 802.11 Networks

Figure 5-1: QoS is measured from endpoint to endpoint, encompassing both the wired and wireless portions of the network.

Figure 5-2: Signal interference on 802.11 wireless networks

Figure 5-3: EA-6B tactical jamming aircraft of the U.S. Navy—the "World-Famous Black Ravens." Coauthor Franklin Ohrtman is the first person on the left, standing.

Figure 5-4: Using any-point-to-multipoint technology to reach a non-line-of-sight subscriber

Figure 5-5: Delay across a network including delay in a gateway (coding and packetizing)

Figure 5-6: Basic access method in DCF and PCF

Figure 5-7: The relationship of CTS and RTS in CSMA/CA

Figure 5-8: Virtual carrier sense protocol

Figure 5-9: Frame fragmentation in virtual carrier sense protocol

Figure 5-10: EDCF and HCF in 802.11 networks

Chapter 6: Voice over 802.11

Figure 6-1: The three components of the PSTN— access, switching, and transport

Figure 6-2: An alternative to the PSTN— 802.11 for access, softswitch for switching, and IP backbone for transport

Figure 6-3: Signaling and transport protocols used in VoIP

Figure 6-4: Proxy server SIP architecture

Figure 6-5: Relationship of softswitch components

Figure 6-6: Process of PSQM

Figure 6-7: Results of Lockheed Martin testing of voice quality using Global IP Sound-enhanced speech software products. Note that a voice quality comparable to the PSTN is achieved. Source— Global IP Sound

Figure 6-9: SpectraLink 802.11 phones and a PBX interface Source— SpectraLink

Figure 6-10: A PDA loaded with softphone is a cost-effective Vo802.11 handset.

Figure 6-11: Linking offices with Vo802.11

Chapter 7: Considerations in Building 802.11 Networks

Figure 7-1: Service sets available in 802.11 standards

Figure 7-2: A wireless star network

Figure 7-3: A wireless mesh network

Figure 7-4: First and second Fresnel Zones

Figure 7-5: Calculating a link budget

Figure 7-6: 2.4 GHz has three nonoverlapping channels.

Figure 7-7: Three-to-one reuse pattern

Figure 7-8: 5 GHz channels

Figure 7-9: Four-to-one reuse pattern

Figure 7-10: Seven-to-one reuse pattern with a spare

Figure 7-11: Overlap in a central library

Figure 7-12: Cells are 3-D in buildings.

Figure 7-13: A case where RF planning is difficult

Figure 7-14: 802.11 client adapter choices

Figure 7-15: Coverage from an omni-directional antenna

Figure 7-16: Collinear antenna

Figure 7-17: Patch antenna

Figure 7-18: Coverage from a directional antenna

Figure 7-19: Panel antenna

Figure 7-20: Yagi antenna in a radome

Figure 7-21: Parabolic grid antenna

Figure 7-22: Multiple wave paths in an unobstructed field

Figure 7-23: Intersymbol interference

Figure 7-24: Multipath

Figure 7-25: A Rake receiver

Figure 7-26: PoE in an office

Figure 7-27: PoE in WLAN

Figure 7-28: Simplified schematic of PoE injector and tap

Figure 7-29: Tiered network to overcome line-of-sight limitation

Figure 7-30: Using a hotspot in a box

Figure 7-31: Hotel or MDU using fiber

Figure 7-32: Hotel or MDU using LRE

Figure 7-33: Hotel or MDU using CATV

Figure 7-34: Using layering to provide hotspot service

Chapter 8: Economic Aspects of Wi-Fi

Figure 8-1: Using Vo802.11 in interoffice telephony saves on both local and longdistance phone bills.

Figure 8-2: Wi-Fi deployment in a cafe or coffee shop hot spot, Source— Pronto Networks

Figure 8-3: Wi-Fi deployment in an airport, Source— Pronto Networks

Figure 8-4: Wi-Fi deployment in a business hotel, Source— Pronto Networks

Figure 8-5: Wi-Fi deployment in an MDU, also known as apartments or condominiums, Source— Pronto Networks

Figure 8-6: Layering is the resell of corporate bandwidth to the public in nearby locations.

Figure 8-7: The economic pull-through of wireless broadband, Source— Goldman Sachs

Chapter 9: Regulatory Aspects of 802.11

Figure 9-1: Interference temperature Source— FCC

Chapter 10: Conclusion

Figure 10-1: The transition from a PSTN to an Internet infrastructure