You are previewing 802.11 Wireless LAN Fundamentals.
O'Reilly logo
802.11 Wireless LAN Fundamentals

Book Description

Master the basics in designing, building, and managing a Cisco Aironet WLAN.

  • Master the basics of Wireless LANs with this concise design and deployment guide

  • Understand implementation issues for a variety of environments including vertical, SOHO, and enterprise networks

  • Learn design and troubleshooting advice from real-world case studies

  • 802.11 Wireless LAN Fundamentals gives networking engineers and IT professionals the knowledge they need to design, deploy, manage, and troubleshoot their own wireless local-area networks (WLANs). Starting with an overview of the technology and architecture of WLANs, the book goes on to explain services and advanced features that such applications can provide. Most importantly, it provides practical design guidance and deployment recommendations.

    Wireless LANs connect computer networks via radio transmissions instead of traditional phone lines or cables. Benefits to these systems go well beyond getting rid of all the cables and wires. Campus networks can grow geographically larger while still retaining all their efficiency and speed. Additionally, cost savings can be realized when third-party phone lines are no longer necessary, saving the cost of line rental and equipment upkeep. Finally, flexibility in campus network design increases significantly for the networking professional, while the network accessibility and usefulness increases for the individual users.

    802.11 Wireless LAN Fundamentals helps networking professionals realize these benefits by helping them understand how to design, build, and maintain these networks, as well as how to justify their value within organizations.

    Table of Contents

    1. Copyright
      1. Dedications
    2. About the Authors
    3. About the Technical Reviewers
    4. Acknowledgments
    5. Icons Used in This Book
    6. Command Syntax Conventions
    7. Foreword
    8. Introduction
      1. How This Book Is Organized
    9. 1. Ethernet Technologies
      1. 802.3 Ethernet
        1. 802.3 Ethernet and the OSI Model
        2. The 802.3 Frame Format
        3. Ethernet Addressing
        4. CSMA/CD Architecture
        5. Ethernet Network Diameter and Ethernet Slot Time
        6. Unicast, Multicast, and Broadcast Frames
        7. Common Media
      2. 802.3u Fast Ethernet
        1. Full-Duplex Operation
      3. Gigabit Ethernet
        1. 802.3ab 1000BASE-T
        2. 802.3z 1000BASE-X
        3. Gigabit Ethernet Slot Time
        4. Auto Negotiation
        5. Gigabit Ethernet Auto Negotiation
      4. Summary
    10. 2. 802.11 Wireless LANs
      1. Overview of WLAN Topologies
        1. IBSS
        2. BSS
        3. ESS
      2. 802.11 Medium Access Mechanisms
        1. Overview of CSMA/CA
          1. Carrier Sense
          2. DCF
          3. The Acknowledgment Frame
          4. The Hidden Node Problem and RTS/CTS
        2. 802.11 Frame Fragmentation
        3. PCF
          1. The Contention Free Period
          2. PC Operation
          3. PCF Operation Example
      3. Nonstandard Devices
        1. Repeater APs
        2. Universal Clients and Workgroup Bridges
        3. Wireless Bridges
      4. 802.11 MAC Layer Operations
        1. Station Connectivity
          1. The Probe Process
          2. The Authentication Process
          3. The Association Process
        2. Power Save Operation
          1. Unicast Power Save Operation
          2. Broadcast
        3. 802.11 MAC Frame Formats
          1. 802.11 Control Frames
            1. The PS-Poll Frame
            2. The RTS Frame
            3. The CTS Frame
            4. The ACK Frame
            5. The CF-End and CF-End+CF-ACK Frames
          2. 802.11 Management Frame Fields and Elements
            1. The SSID IE
            2. The Supported Rates IE
            3. FH Parameter Set IE
            4. The DS Parameter Set IE
            5. The CF Parameter Set IE
            6. The TIM IE
            7. The IBSS Parameter Set IE
            8. The Challenge Text IE
          3. 802.11 Fixed Field Elements
            1. The Authentication Algorithm Number Field
            2. The Authentication Transaction Sequence Number Field
            3. The Beacon Interval Field
            4. The Capability Information Field
            5. The Current AP Address Field
            6. The Listen Interval Field
            7. The Reason Code Field
            8. The AID Field
            9. The Status Code Field
            10. The Timestamp Field
          4. 802.11 Management Frames
            1. The Beacon Frame
            2. The Probe Request Frame
            3. The Probe Response Frame
            4. The Authentication Frame
            5. The Deauthentication Frame
            6. The Association Request Frame
            7. The Association Response Frame
            8. The Reassociation Request Frame
            9. The Reassociation Response Frame
            10. The Disassociation Frame
            11. The ATIM
          5. 802.11 Data Frames
            1. The Data Frame
            2. The Data+CF-Ack, Data+CF-Poll, and Data+CF-Ack+CF-Poll Frames
            3. The Null Data
            4. The CF-Ack, CF-Poll, and CF-Ack+CF-Poll Frames
      5. Summary
    11. 3. 802.11 Physical Layer Technologies
      1. Wireless Physical Layer Concepts
        1. Physical Layer Building Blocks
          1. Scrambling
          2. Coding
          3. Interleaving
          4. Symbol Mapping and Modulation
      2. 802.11 Wireless LANs
        1. Frequency Hopping WLANs
          1. FHSS PLCP
          2. FHSS PMD-GFSK Modulation
        2. Direct Sequence Spread Spectrum WLANs
          1. 802.11 DSSS
          2. DSSS Basics
          3. DBPSK Modulation
          4. DQPSK Modulation
      3. 802.11b WLANs
        1. 802.11b HR-DSSS PLCP
        2. 802.11b PMD—CCK Modulation
        3. PBCC Modulation
      4. 802.11a WLANs
        1. 802.11j
        2. 802.11a OFDM PLCP
        3. OFDM Basics
        4. OFDM Training
        5. 802.11a OFDM PMD
      5. 802.11g WLANs
        1. 802.11g PLCP
        2. ERP-OFDM
        3. ERP-PBCC
        4. 802.11g Summary
      6. CCA
      7. Summary
    12. 4. 802.11 Wireless LAN Security
      1. Wireless Security
      2. Overview of Encryption
        1. Initialization Vectors
        2. Feedback Modes
      3. Encryption in the 802.11 Standard
      4. Authentication Mechanisms in the 802.11 Standard
      5. MAC Address Authentication
      6. Security Vulnerabilities in the 802.11 Standard
        1. Open Authentication Vulnerabilities
        2. Shared Key Authentication Vulnerabilities
        3. MAC Address Authentication Vulnerabilities
        4. WEP Encryption Vulnerabilities
        5. Static WEP Key Management Issues
      7. Secure 802.11 WLANs
        1. Facet 1: The Authentication Framework
        2. Facet 2: The Authentication Algorithm
        3. Facet 3: Data Privacy
        4. Data Integrity
        5. Enhanced Key Management
      8. AES Encryption
      9. Summary
    13. 5. Mobility
      1. Characteristics of Roaming
        1. The Nature of Roaming in 802.11
        2. Operation of the Application
        3. Roaming Domain
        4. Roaming Duration
      2. Layer 2 Roaming
        1. Roaming Algorithms
        2. Determining Where to Roam
          1. Preemptive AP Discovery
          2. Roam-Time AP Discovery
        3. Layer 2 Roaming Process
      3. Layer 3 Roaming
        1. Roaming Between Roaming Domains
        2. Mobile IP Overview
          1. Agent Discovery
          2. MN Registration
        3. Tunneling
      4. Summary
    14. 6. QoS for 802.11 Wireless LANs—802.11e
      1. Challenges for QoS in 802.11 Networks
        1. QoS Impact of a Half-Duplex Medium
        2. Cochannel Overlap
        3. Hidden Node Impact on QoS
      2. QoS Mechanism Overview
        1. HCF in Contention Mode—The EDCF Access Mechanism
          1. Channel Access for Differentiated Traffic
          2. Admission Control with EDCF
        2. HCF in Controlled Access Mode
          1. Contention-Free HCF Operation
          2. Interoperation of EDCF and HCF
          3. Admission Control with HCF
      3. Summary: The Challenges Facing EDCF and HCF
    15. 7. Radio Frequency Essentials
      1. Radio Basics
      2. Antenna Basics
        1. Antenna Properties
        2. Types of Antennas
      3. Receiver Performance Basics
        1. 802.11b Minimum Radio Performance
        2. 802.11a Minimum Radio Performance
      4. System Performance
      5. Unlicensed Wireless
        1. ISM Band Frequencies
        2. 2.4 GHz ISM Band Transmit Power Levels
      6. U-NII Band WLAN Frequencies
        1. U-NII Band Spurious Emissions and Spectral Masks
        2. U-NII Band Transmit Power Limitations
      7. Summary
    16. 8. Deploying Wireless LANs
      1. WLAN Deployment and Application Impact
      2. WLAN Deployment Planning
        1. Coverage-Oriented WLANs
        2. Capacity-Oriented WLANs
        3. Phased AP Deployment—Migrating from Coverage-Oriented Deployments to Capacity-Oriented Deployments
      3. Site Survey
        1. Site Survey Challenges
        2. Site Survey Tools
        3. Conducting the Survey
      4. Upper-Layer Considerations
        1. 802.1X Deployment Considerations
          1. Prioritizing 802.1X RADIUS Packets Using IP QoS
          2. Local Authentication at Remote Sites
        2. Managing WLANs
      5. Summary
    17. 9. The Future of Wireless LANs
      1. Bluetooth
      2. UWB
      3. FSO
      4. 100 Mbps WLANs
      5. Summary
    18. 10. WLAN Design Considerations
      1. Considerations for Retail Stores
      2. Healthcare Design Considerations
      3. Enterprise Branch Office and Telecommuter Design Considerations
        1. Design Considerations for Enterprise Branch Office Deployments
        2. Design Considerations for Enterprise Telecommuters
      4. Education Design Considerations
      5. Public Access Design Considerations
      6. Public Safety Design Considerations
      7. Summary
    19. Glossary