Wireless Networks The Definitive Guide

Transcription

1 SECOND EDITION Wireless Networks The Definitive Guide Matthew S. Gast ULB Darmstadt Illlllllllllllllllllllll,., s b f m ' Koln " Sebastopol Tokyo

2 Table of Contents Foreword Preface ix xi 1. Introduction to Wireless Networking 1 Why Wireless? 1 What Makes Wireless Networks Different 5 A Network by Any Other Name Overview of Networks 12 IEEE 802 Network Technology Family Tree Nomenclature and Design Network Operations 23 Mobility Support MAC Fundamentals 32 Challenges for the MAC 34 MAC Access Modes and Timing 37 Contention-Based Access Using the DCF 41 Fragmentation and Reassembly 44 Frame Format 46 Encapsulation of Higher-Layer Protocols Within Contention-Based Data Service 55 Frame Processing and Bridging 63

3 Framing in Detail 67 Data Frames 67 Control Frames 76 Management Frames 82 Frame Transmission and Association and Authentication States Wired Equivalent Privacy (WEP) 114 Cryptographic Background to WEP 114 WEP Cryptographic Operations 117 Problems with WEP 123 Dynamic WEP User Authentication with X 129 The Extensible Authentication Protocol 130 EAP Methods IX: Network Port Authentication IX on Wireless LANs i: Robust Security Networks, TKIP, and CCMP 149 The Temporal Key Integrity Protocol (TKIP) 149 Counter Mode with CBC-MAC (CCMP) 159 Robust Security Network (RSN) Operations Management Operations 170 Management Architecture * Scanning 171 Authentication 176 Preauthentication 180 Association 184 Power Conservation 188 Timer Synchronization 197 Spectrum Management Contention-Free Service with the PCF 214 Contention-Free Access Using the PCF 214 Detailed PCF Framing 218 Power Management and the PCF 223 Table of Contents

4 10. Physical Layer Overview 225 Physical-Layer Architecture 225 The Radio Link 226 RF Propagation with RF Engineering for The Frequency-Hopping (FH) PHY 241 Frequency-Hopping Transmission 241 Gaussian Frequency Shift Keying (GFSK) 246 FH PHY Convergence Procedure (PLCP) 249 Frequency-Hopping PMD Sublayer 250 Characteristics of the FH PHY The Direct Sequence PHYs: DSSS and HR/DSSS (802.11b) 253 Direct Sequence Transmission 253 Differential Phase Shift Keying (DPSK) 260 The "Original" Direct Sequence PHY 263 Complementary Code Keying 267 High Rate Direct Sequence PHY a and j: 5-GHz0FDM PHY 276 Orthogonal Frequency Division Multiplexing (OFDM) 277 OFDM as Applied by a 282 OFDM PLCP * OFDM PMD 293 Characteristics of the OFDM PHY g: The Extended-Rate PHY (ERP) lg Components 298 ERP Physical Layer Convergence (PLCP) 304 ERP Physical Medium Dependent (PMD) Layer A Peek Ahead at802.11n: MIM0-0FDM 311 Common Features 312 WWiSE 314 TGnSync 325 Comparison and Conclusions 340 Table of Contents

5 Hardware 343 General Structure of an Interface 343 Implementation-Specific Behavior 348 Reading the Specification Sheet Using on Windows 353 Windows XP 353 Windows Windows Computer Authentication on the Macintosh 373 The AirPort Extreme Card XontheAirPort Using on Linux 387 PCMCIA Support on Linux 387 Linux Wireless Extensions and Tools 395 Agere (Lucent) Orinoco 402 Atheros-Based cards and MADwifi IX on Linux with xsupplicant Using Access Points 415 General Functions of an Access Point 416 Power over Ethernet (PoE) 422 Selecting Access Points *. 424 Cisco 1200 Access Point 427 Apple AirPort Logical Wireless Network Architecture 438 Evaluating a Logical Architecture 438 Topology Examples 452 Choosing Your Logical Architecture Security Architecture 476 Security Definition and Analysis 477 Authentication and Access Control 482 Ensuring Secrecy Through Encryption 492 vi Table of Contents

6 Selecting Security Protocols 500 Rogue Access Points Site Planning and Project Management 518 Project Planning and Requirements 519 Network Requirements 521 Physical Layer Selection and Design 532 Planning Access-Point Placement 537 Using Antennas to Tailor Coverage Network Analysis 553 Network Analyzers 553 Ethereal Network Analysis Checklist 566 Other Tools Performance Tuning Performance Calculations 573 Improving Performance 576 Tunable Parameters Conclusions and Predictions 585 Standards Work 585 Current Trends in Wireless Networking 587 The End,. 596 Glossary 597 Index 607 Table of Contents I vii