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802.11ac: A Survival Guide

Book Description

The next frontier for wireless LANs is 802.11ac, a standard that increases throughput beyond one gigabit per second. This concise guide provides in-depth information to help you plan for 802.11ac, with technical details on design, network operations, deployment, and monitoring.

Author Matthew Gast—an industry expert who led the development of 802.11-2012 and security task groups at the Wi-Fi Alliance—explains how 802.11ac will not only increase the speed of your network, but its capacity as well. Whether you need to serve more clients with your current level of throughput, or serve your existing client load with higher throughput, 802.11ac is the solution. This book gets you started.

  • Understand how the 802.11ac protocol works to improve the speed and capacity of a wireless LAN
  • Explore how beamforming increases speed capacity by improving link margin, and lays the foundation for multi-user MIMO
  • Learn how multi-user MIMO increases capacity by enabling an AP to send data to multiple clients simultaneously
  • Plan when and how to upgrade your network to 802.11ac by evaluating client devices, applications, and network connections

Table of Contents

  1. Dedication
  2. Foreword
  3. Preface
    1. Audience
    2. Conventions Used in This Book
    3. Safari® Books Online
    4. How to Contact Us
    5. Acknowledgments
  4. 1. Introduction to 802.11ac
    1. History
    2. The Core Technology of 802.11ac
      1. Beamforming and Multi-User MIMO (MU-MIMO)
      2. Operating Frequency Band for 802.11ac
    3. 802.11ac Product Development Plans
  5. 2. The PHY
    1. Extended MIMO Operations
    2. Radio Channels in 802.11ac
      1. Radio Channel Layout
        1. Radio channel spectral mask
      2. Available Channel Map
    3. Transmission: Modulation, Coding, and Guard Interval
      1. Modulation and Coding Set (MCS)
        1. 256-QAM modulation
      2. Guard Interval
      3. Error-Correcting Codes
    4. PHY-Level Framing
      1. The VHT Signal Fields
        1. VHT Signal A field
        2. VHT Signal B field
      2. The Data Field
    5. The Transmission and Reception Process
    6. 802.11ac Data Rates
      1. 802.11ac Data Rate Matrix
        1. “Missing” MCS values
      2. Comparison of 802.11ac Data Rates to Other 802.11 PHYs
    7. Mandatory PHY Features
  6. 3. The MAC
    1. Framing
      1. Frame Size and Aggregation
      2. Management Frames
        1. The VHT Capabilities Information element
        2. The VHT Operation Information element
        3. Other management frame changes
    2. Medium Access Procedures
      1. Clear-Channel Assessment (CCA)
        1. Basic channel access rules
        2. Sensitivity requirements
      2. Protection and Coexistence of 802.11ac with Older 802.11 Devices
      3. Dynamic Bandwidth Operation (RTS/CTS)
    3. Security
    4. Mandatory MAC Features
  7. 4. Beamforming in 802.11ac
    1. Beamforming Basics
      1. Null Data Packet (NDP) Beamforming in 802.11ac
        1. Channel measurement (sounding) procedures
        2. The feedback matrix
    2. Single-User (SU) Beamforming
      1. Channel Calibration for Single-User Beamforming
        1. NDP Announcement frame
        2. NDP frame
        3. VHT Compressed Beamforming Action frame
    3. Multi-User (MU) Beamforming
      1. Channel Calibration for Multi-User Beamforming
        1. NDP Announcement frame
        2. NDP frame
        3. Compressed Beamforming Action frame
        4. Beamforming Report Poll frame
      2. Multi-User MIMO Transmission
        1. PHY changes for MU-MIMO
        2. Transmission and reception of multi-user data streams
      3. MU-MIMO Implementation
        1. Null steering
        2. Acknowledgement in MU-MIMO
        3. Queuing and quality of service
  8. 5. 802.11ac Planning
    1. Getting Ready for 802.11ac
      1. Catching the 802.11ac Technology Wave
        1. First wave 802.11ac versus second wave 802.11ac
      2. Client Device Mix
      3. Application Planning
        1. Admission control
      4. Physical Network Connections
        1. Backbone connectivity
        2. Power requirements
      5. Security
        1. Link-layer encryption
        2. Fast roaming
        3. Management frame protection
        4. Authentication
      6. Additional Planning Considerations
        1. Guest management
        2. Intrusion detection
    2. 802.11ac Radio Planning
      1. Available Radio Channels
      2. Coverage and Capacity Estimates
        1. Initial 802.11ac AP mounting locations
        2. 5 GHz coverage and 802.11ac-only APs
      3. Equipment Selection
      4. Network Architecture for 802.11ac
        1. Architecture comparison
        2. Selecting a network architecture
          1. Management plane
          2. Data plane
          3. Control plane
      5. Hardware Considerations
        1. Mandatory tests
        2. Optional tests
    3. Building an 802.11ac Network
      1. Channel Selection
      2. Network Tuning and Optimization
        1. Voice
        2. Multicast
    4. Checklist
  9. Glossary
  10. Colophon
  11. Copyright