Description
Book SynopsisThis book is part of the IEEE Standards Wireless Networks Series. This book describes Wireless Local Area Networks Quality of Service enhancements. Those enhancements enable the support of real-time applications such as voice and video. The scope of the book includes: - Overview of QoS mechanisms and architectures. - WLAN QoS mechanisms and relationship to QoS general architectures. - Performance analysis and case studies. WLAN QoS planning and engineering are challenging tasks to both network operators and end users. This book is an attempt to satisfy the need for better understanding of WLAN QoS features as well as the related engineering challenges. The reader will be able to understand WLAN QoS mechanisms and features in a simple and clear way beyond that obtained by just reading standard documents. The reader of the book should be able to understand: - WLAN QoS basic operation. How WLAN QoS is related to other QoS architectures especially IP QoS, and the related interworking issue
Table of ContentsPreface xi
Acronyms xv
Chapter 1 Quality of Service Mechanisms and Metrics 1
Traffic Management Mechanisms 1
Traffic Conditioning 4
The Metering Function 5
Marker 9
Dropper 9
Shaper 10
Admission Control 11
Nodal Mechanisms 15
Transmission Scheduler 15
Buffer Management 22
Feedback Congestion Management 26
Performance Metrics 31
Throughput 32
Delay 33
Packet Loss 36
Simple Queueing Models 36
M\M\l Queueing System 38
M\G\ 1 Queueing System 41
Chapter 2 QoS Architectures 43
Reservation Model 43
Reservation Model Example 45
Service Types 49
Differentiation Model 54
Differentiating Model Examples 56
IEEE Standard 802. IQ Ethernet Frame Priority 62
Chapter 3 IEEE Standard 802.11 Overview 65
IEEE 802.11 Architecture and Frame format 65
IEEE 802.11 PHY Overview 69
IEEE 802.1 la PHY 69
IEEE 802.1 lb PHY 71
The IEEE 802.1 lg PHY Overview 73
The IEEE 802.11 MAC Overview 75
Distributed Coordination Function (DCF) 75
Point Coordination Function (PCF) 81
Power Management 85
IEEE 802.11 Throughput 86
IEEE 802.11 Frame Types 90
A Queueing Model for PCF Performance 92
Chapter 4 IEEE 802.11 QoS Features 97
IEEE 802.1 le MAC Overview 97
Data Frame Format 99
Association to QoS BSS 102
EDCA Operation 105
HCCA Operation 108
Admission Control 110
EDCA Admission Control 119
HCCA Admission Control 123
Direct Link Setup 125
Block Acknowledgment (BA) 129
Throughput Improvement Due to Block Acknowledgment 132
Power Management Using APSD 134
WiFi Multimedia (WMM) Specification 136
IEEE 802.1 In (High Throughput) MAC Features 139
Frame Aggregation 139
IEEE 802.1 In Block Acknowledgment 141
A Simple Engineering Example 143
Chapter 5 Interworking with WLAN QoS 145
Common WLAN Deployment Scenario 147
WLAN QoS Interworking with Ethernet 148
WLAN QoS Interworking with IP Networks 151
Chapter 6 Concluding Remarks 157
Bibliography 159
Index 163
