802.11n: A Survival Guide

802.11n: A Survival Guide

by Matthew S. Gast
Released April 2012
Publisher(s): O'Reilly Media, Inc.
ISBN: 9781449335496

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Book description

Wireless has finally come of age. With a significant jump in throughput over previous standards, 802.11n is the first wireless technology that doesn’t trade speed for mobility, and users have stormed onto wireless networks with a passion. In this concise guide, Matthew Gast—chair of the IEEE group that produced revision 802.11-2012—shows you why wireless has become the default method of connecting to a network, and provides technical details you need to plan, design, and deploy 802.11n today.

Building a network for the multitude of new devices is now a strategic decision for network engineers everywhere. This book gives you an in-depth look at key parts of 802.11n, and shows you how to achieve an Ethernet-free wireless office.

  • Learn how MIMO’s multiple data streams greatly increase wireless speed
  • Discover how 802.11n modifications improve MAC efficiency
  • Examine advanced PHY features such as beanforming and space-time code block
  • Use advanced MAC features to maintain interoperability with older devices
  • Plan an 802.11n network by determining traffic demand, key applications, power requirements, and security
  • Choose the architecture, select hardware, and plan coverage to design and build your network

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Table of contents

  1. 802.11n: A Survival Guide
  2. Dedication
  3. Foreword
  4. Preface
    1. Audience
    2. Conventions Used in This Book
    3. Using Code Examples
    4. Safari® Books Online
    5. How to Contact Us
    6. Acknowledgments
  5. 1. Introduction to 802.11n-2009
    1. History
    2. The Technology of 802.11n
      1. Physical Layer (PHY) Enhancements
      2. Link Layer (MAC) Enhancements
    3. 802.11n: First We Take the LAN, Then We Take the World
  6. I. The PHY
    1. 2. MIMO and the 802.11n PHY
      1. The Big Idea: MIMO and Data Streams
        1. Spatial Streams
        2. Radio Chains
        3. Relationship Between Spatial Streams and Radio Chains
    2. 3. Channels, Framing, and Coding
      1. Channel Structure and Layout
        1. Channel Structure
        2. Regulatory Rules and Operating Channels
      2. Transmission: Modulation and Guard Interval
        1. Modulation and Coding Set (MCS)
          1. Forward Error Correcting Codes in 802.11n
        2. Guard Interval
      3. PLCP Framing
        1. HT Mixed Mode PLCP Format
          1. HT Signal Field
          2. Data Field
      4. Transmission and Reception Process
      5. 802.11n Speed
        1. Comparison 1: 802.11a/g versus 1x1 11n
        2. Comparison 2: 20 MHz versus 40 MHz channels
      6. Mandatory PHY Features
    3. 4. Advanced PHY Features for Performance
      1. Beamforming
        1. Types of Beamforming
      2. Space-Time Block Code (STBC)
      3. Low-Density Parity Check (LDPC)
  7. II. The MAC
    1. 5. MAC Basics
      1. Frame Changes
      2. Airtime Efficiency Improvements
        1. A-MPDU
          1. A-MPDU Density
        2. A-MSDU
        3. Aggregation Compared
        4. Block Acknowledgment
        5. Reduced Interfame Space (RIFS)
      3. Protection of Non-HT Transmissions
        1. Protection Mechanisms
          1. PHY-layer protection: L-SIG duration in HT-Mixed Mode
          2. MAC-layer protection: CTS-to-self
          3. MAC layer protection: transmission mode switch
        2. Protection Rules
      4. Security
      5. Mandatory MAC Features
    2. 6. Advanced MAC Features for Interoperability
      1. Radio Medium Coordination
        1. Clear-Channel Assessment (CCA)
        2. Channel Width Selection (20/40 MHz BSS)
          1. Channel access rules
        3. 40 MHz Intolerance for Channel Width Interoperability
      2. Power-Saving
        1. Spatial Multiplexing (SM) Power Save
        2. Power-Save Multi-Poll (PSMP)
  8. III. Using 802.11n to Build a Network
    1. 7. Planning an 802.11n Network
      1. What’s On Your Network?
        1. Mobile End-User Devices
          1. 802.11n and Single-Stream Clients
        2. Traffic and Application Mix
      2. Network Integration
        1. Network Services
          1. Edge services
          2. Network-wide services
          3. Remote services
        2. Backbone Connectivity
        3. Power Requirements
      3. Security
        1. TKIP Transition Planning and Support
          1. Separate SSIDs
          2. Simultaneous support of TKIP and CCMP
        2. User Authentication
      4. Design Checklist
    2. 8. Designing and Installing an 802.11n Network
      1. Network Architecture for 802.11n
        1. Architecture Comparison
          1. Management plane
          2. Data plane
          3. Control plane
      2. 802.11n Hardware
        1. Technology “Waves”
        2. Wi-Fi Alliance Certification
          1. Mandatory tests
          2. Optional tests
      3. Coverage and Capacity Planning
        1. AP Mounting Locations
        2. Channel Types and Layout
        3. AP Transmit Power Setting
      4. Network Management
        1. Network Analysis
        2. Network Tuning
          1. Tuning for voice
          2. Tuning for multicast
      5. Implementation Checklist
  9. A. Afterword
  10. Glossary
  11. About the Author
  12. Copyright

Product information

  • Title: 802.11n: A Survival Guide
  • Author(s): Matthew S. Gast
  • Release date: April 2012
  • Publisher(s): O'Reilly Media, Inc.
  • ISBN: 9781449335496