Computer Networks - Performance and QOS

510 Pages·2010·12.954 MB·English

by  I. Marsic

Last updated: December 24, 2010

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Performannccee and QQuality of Servicee

Ivan Marsic
Department of Electrical and Computer Engineering
Rutgers University
Copyright © 2010 by Ivan Marsic. All rights reserved.

Book website: http://www.ece.rutgers.edu/~marsic/books/QoS/
Preface

This book reviews modern computer networks with a particular focus on performance and quality
of service. There is a need to look towards future, where wired and wireless/mobile networks will
be mixed and where multimedia applications will play greater role. In reviewing these
technologies, I put emphasis on underlying principles and core concepts, rather than
meticulousness or completeness.
Audience
This book is designed for upper-division undergraduate and graduate courses in computer
networking. It is intended primarily for learning, rather than reference. I also believe that the
book’s focus on basic concepts should be appealing to practitioners interested in the “whys”
behind the commonly encountered networking technologies. I assume that the readers will have
basic knowledge of probability and statistics, which are reviewed in the Appendix. Most concepts
do not require mathematical sophistication beyond a first undergraduate course.
Most of us have a deep desire to understand logical cause-effect relationships in our world.
However, some topics are either inherently difficult or poorly explained and they turn us off. I
tried to write a computer networking book for the rest of us, one that has a light touch but is still
substantial. I tried to present a serious material in a fun way so the reader may have fun and learn
something nontrivial. I do not promise that it will be easy, but I hope it will be worth your effort.
Approach and Organization
In structuring the text, I faced the choice between logically grouping the topics vs. gradually
identifying and addressing issues. The former creates a neater structure and the latter is more
suitable for teaching new material. I compromised by opportunistically adopting both approaches.
I tried to make every chapter self-contained, so that entire chapters can be skipped if necessary.
Chapter 1 reviews essential networking technologies. It is condensed but more technical than
many current networking books. I tried to give an engineering overview that is sufficiently
detailed but not too long. This chapter serves as the basis for the rest of the book.
Chapter 2 reviews the mechanisms for congestion control and avoidance in data networks. Most
of these mechanisms are implemented in different variants of Transmission Control Protocol
(TCP), which is the most popular Internet protocol.
Chapter 3 reviews requirements and solutions for multimedia networking.
Chapter 4 describes how network routers forward data packets. It also describes simple
techniques for modeling queuing delays.
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Ivan Marsic • Rutgers University ii
Chapter 5 describes router techniques for reducing or redistributing queuing delays across data
packets. These include scheduling and policing the network traffic.
Chapter 6 describes wireless networks, focusing on the network and link layers, rather than on
physical layer issues.
Chapter 7 describes network measurement techniques.
Chapter 8 describes major protocols used in the Internet that I are either not essential or are
specific implementations of generic protocols presented in earlier chapters. The most essential
Internet protocols, such as TCP and IP are presented in earlier chapters.
The Appendix provides a brief review of probability and statistics.
Solved Problems
This book puts great emphasis on problems for two reasons. First, I believe that specific problems
are the best way to explain difficult concepts. Second, I wanted to keep the main text relatively
short and focused on the main concepts; therefore, I use problems to illustrate less important or
advanced topics. Every chapter (except for Chapter 9) is accompanied with a set of problems.
Solutions for most of the problems can be found at the back of the text, starting on page 401.
Additional information about team projects and online links to related topics can be found at the
book website: http://www.ece.rutgers.edu/~marsic/books/QoS/.

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Contents at a Glance

PREFACE ...................................................................................................................................................... I
CONTENTS AT A GLANCE .................................................................................................................... III
TABLE OF CONTENTS ........................................................................................................................... IV
CHAPTER 1 INTRODUCTION TO COMPUTER NETWORKS .................................................. 1
CHAPTER 2 TRANSMISSION CONTROL PROTOCOL (TCP) ...............................................139
CHAPTER 3 MULTIMEDIA AND REAL-TIME APPLICATIONS ...........................................181
CHAPTER 4 SWITCHING AND QUEUING DELAY MODELS ................................................218
CHAPTER 5 MECHANISMS FOR QUALITY-OF-SERVICE ....................................................256
CHAPTER 6 WIRELESS NETWORKS .........................................................................................296
CHAPTER 7 NETWORK MONITORING .....................................................................................331
CHAPTER 8 INTERNET PROTOCOLS .......................................................................................337
CHAPTER 9 TECHNOLOGIES AND FUTURE TRENDS ..........................................................376
PROGRAMMING ASSIGNMENTS .......................................................................................................393
SOLUTIONS TO SELECTED PROBLEMS..........................................................................................401
APPENDIX A: PROBABILITY REFRESHER .....................................................................................471
REFERENCES ..........................................................................................................................................483
ACRONYMS AND ABBREVIATIONS ..................................................................................................491
INDEX ........................................................................................................................................................494

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Table of Contents

PREFACE ...................................................................................................................................................... I
CONTENTS AT A GLANCE .................................................................................................................... III
TABLE OF CONTENTS ........................................................................................................................... IV
CHAPTER 1 INTRODUCTION TO COMPUTER NETWORKS .................................................. 1
1.1 INTRODUCTION .............................................................................................................................. 1
1.1.1 The Networking Problem .......................................................................................................... 1
1.1.2 Communication Links ............................................................................................................... 5
1.1.3 Packets and Statistical Multiplexing ......................................................................................... 9
1.1.4 Communication Protocols ...................................................................................................... 10
1.2 RELIABLE TRANSMISSION VIA REDUNDANCY .............................................................................. 23
1.2.1 Error Detection and Correction by Channel Coding ............................................................. 23
1.2.2 Interleaving ............................................................................................................................. 24
1.3 RELIABLE TRANSMISSION BY RETRANSMISSION .......................................................................... 25
1.3.1 Stop-and-Wait ......................................................................................................................... 29
1.3.2 Sliding-Window Protocols ...................................................................................................... 32
1.3.3 Broadcast Links ...................................................................................................................... 36
1.4 ROUTING AND ADDRESSING ........................................................................................................ 50
1.4.1 Networks, Internets, and the IP Protocol ............................................................................... 53
1.4.2 Link State Routing .................................................................................................................. 60
1.4.3 Distance Vector Routing ......................................................................................................... 64
1.4.4 IPv4 Address Structure and CIDR .......................................................................................... 69
1.4.5 Autonomous Systems and Path Vector Routing ...................................................................... 76
1.5 LINK-LAYER PROTOCOLS AND TECHNOLOGIES ........................................................................... 86
1.5.1 Point-to-Point Protocol (PPP) ............................................................................................... 88
1.5.2 Ethernet (IEEE 802.3) ............................................................................................................ 91
1.5.3 Wi-Fi (IEEE 802.11) ..............................................................................................................103
1.6 QUALITY OF SERVICE OVERVIEW ...............................................................................................112
1.6.1 QoS Outlook ..........................................................................................................................115
1.6.2 Network Neutrality vs. Tiered Services ..................................................................................116
1.7 SUMMARY AND BIBLIOGRAPHICAL NOTES .................................................................................117
PROBLEMS ...............................................................................................................................................122
CHAPTER 2 TRANSMISSION CONTROL PROTOCOL (TCP) ...............................................139
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2.1 INTRODUCTION ...........................................................................................................................139
2.1.1 Reliable Byte Stream Service .................................................................................................140
2.1.2 Retransmission Timer ............................................................................................................144
2.1.3 Flow Control .........................................................................................................................147
2.2 CONGESTION CONTROL ..............................................................................................................150
2.2.1 TCP Tahoe .............................................................................................................................157
2.2.2 TCP Reno ...............................................................................................................................160
2.2.3 TCP NewReno .......................................................................................................................163
2.3 FAIRNESS ....................................................................................................................................170
2.4 RECENT TCP VERSIONS..............................................................................................................171
2.5 TCP OVER WIRELESS LINKS .......................................................................................................171
2.6 SUMMARY AND BIBLIOGRAPHICAL NOTES .................................................................................172
PROBLEMS ...............................................................................................................................................175
CHAPTER 3 MULTIMEDIA AND REAL-TIME APPLICATIONS ...........................................181
3.1 APPLICATION REQUIREMENTS ....................................................................................................181
3.1.1 Application Types ..................................................................................................................182
3.1.2 Standards of Information Quality ..........................................................................................186
3.1.3 User Models ...........................................................................................................................188
3.1.4 Performance Metrics .............................................................................................................191
3.2 SOURCE CHARACTERISTICS AND TRAFFIC MODELS ....................................................................193
3.2.1 Traffic Descriptors ................................................................................................................193
3.2.2 Self-Similar Traffic ................................................................................................................194
3.3 APPROACHES TO QUALITY-OF-SERVICE .....................................................................................194
3.3.1 End-to-End Delayed Playout .................................................................................................195
3.3.2 Multicast Routing ..................................................................................................................199
3.3.3 Peer-to-Peer Routing .............................................................................................................207
3.3.4 Resource Reservation and Integrated Services ......................................................................208
3.3.5 Traffic Classes and Differentiated Services ...........................................................................210
3.4 ADAPTATION PARAMETERS ........................................................................................................212
3.5 QOS IN WIRELESS NETWORKS ....................................................................................................212
3.6 SUMMARY AND BIBLIOGRAPHICAL NOTES .................................................................................212
PROBLEMS ...............................................................................................................................................214
CHAPTER 4 SWITCHING AND QUEUING DELAY MODELS ................................................218
4.1 PACKET SWITCHING IN ROUTERS ................................................................................................220
4.1.1 How Routers Forward Packets ..............................................................................................220
4.1.2 Router Architecture ...............................................................................................................222
4.1.3 Forwarding Table Lookup .....................................................................................................226
4.1.4 Switching Fabric Design .......................................................................................................227
4.1.5 Where and Why Queuing Happens ........................................................................................232
4.2 QUEUING MODELS ......................................................................................................................236
4.2.1 Little’s Law ............................................................................................................................239
4.2.2 M / M / 1 Queuing System ......................................................................................................241
4.2.3 M / M / 1 / m Queuing System ................................................................................................244
4.2.4 M / G / 1 Queuing System ......................................................................................................245
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4.3 NETWORKS OF QUEUES ..............................................................................................................248
4.4 SUMMARY AND BIBLIOGRAPHICAL NOTES .................................................................................249
PROBLEMS ...............................................................................................................................................250
CHAPTER 5 MECHANISMS FOR QUALITY-OF-SERVICE ....................................................256
5.1 SCHEDULING ...............................................................................................................................256
5.1.1 Scheduling Disciplines ..........................................................................................................257
5.1.2 Fair Queuing .........................................................................................................................259
5.1.3 Weighted Fair Queuing .........................................................................................................269
5.2 POLICING ....................................................................................................................................270
5.3 ACTIVE QUEUE MANAGEMENT ...................................................................................................271
5.3.1 Random Early Detection (RED) ............................................................................................272
5.3.2 Explicit Congestion Notification (ECN) ................................................................................274
5.4 MULTIPROTOCOL LABEL SWITCHING (MPLS) ...........................................................................274
5.4.1 MPLS Architecture and Operation ........................................................................................276
5.4.2 Label Distribution Protocols .................................................................................................284
5.4.3 Traffic Engineering ................................................................................................................287
5.4.4 Virtual Private Networks .......................................................................................................288
5.4.5 MPLS and Quality of Service ................................................................................................288
5.5 SUMMARY AND BIBLIOGRAPHICAL NOTES .................................................................................289
PROBLEMS ...............................................................................................................................................292
CHAPTER 6 WIRELESS NETWORKS .........................................................................................296
6.1 MESH NETWORKS .......................................................................................................................296
6.2 ROUTING PROTOCOLS FOR MESH NETWORKS ............................................................................297
6.2.1 Dynamic Source Routing (DSR) Protocol .............................................................................298
6.2.2 Ad Hoc On-Demand Distance-Vector (AODV) Protocol ......................................................300
6.3 MORE WIRELESS LINK-LAYER PROTOCOLS ...............................................................................301
6.3.1 IEEE 802.11n (MIMO Wi-Fi) ................................................................................................301
6.3.2 WiMAX (IEEE 802.16) ..........................................................................................................327
6.3.3 ZigBee (IEEE 802.15.4) .........................................................................................................327
6.3.4 Bluetooth ................................................................................................................................327
6.4 WI-FI QUALITY OF SERVICE .......................................................................................................328
6.5 SUMMARY AND BIBLIOGRAPHICAL NOTES .................................................................................329
PROBLEMS ...............................................................................................................................................330
CHAPTER 7 NETWORK MONITORING .....................................................................................331
7.1 INTRODUCTION ...........................................................................................................................331
7.2 AVAILABLE BANDWIDTH ESTIMATION .......................................................................................332
7.2.1 Packet-Pair Technique ..........................................................................................................332
7.3 DYNAMIC ADAPTATION ..............................................................................................................333
7.3.1 Data Fidelity Reduction .........................................................................................................334
7.3.2 Application Functionality Adaptation ...................................................................................335
7.3.3 Computing Fidelity Adaptation .............................................................................................335
7.4 SUMMARY AND BIBLIOGRAPHICAL NOTES .................................................................................336
PROBLEMS ...............................................................................................................................................336
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CHAPTER 8 INTERNET PROTOCOLS .......................................................................................337
8.1 INTERNET PROTOCOL VERSION 6 (IPV6) ....................................................................................337
8.1.1 IPv6 Addresses ......................................................................................................................339
8.1.2 IPv6 Extension Headers ........................................................................................................342
8.1.3 Transitioning from IPv4 to IPv6 ............................................................................................345
8.2 ROUTING PROTOCOLS .................................................................................................................345
8.2.1 Routing Information Protocol (RIP) ......................................................................................345
8.2.2 Open Shortest Path First (OSPF) ..........................................................................................347
8.2.3 Border Gateway Protocol (BGP) ..........................................................................................351
8.2.4 Multicast Routing Protocols ..................................................................................................362
8.3 ADDRESS TRANSLATION PROTOCOLS .........................................................................................363
8.3.1 Address Resolution Protocol (ARP) ......................................................................................363
8.3.2 Dynamic Host Configuration Protocol (DHCP) ...................................................................366
8.3.3 Network Address Translation (NAT) .....................................................................................366
8.3.4 Mobile IP ...............................................................................................................................367
8.4 DOMAIN NAME SYSTEM (DNS) ..................................................................................................369
8.5 NETWORK MANAGEMENT PROTOCOLS .......................................................................................370
8.5.1 Internet Control Message Protocol (ICMP) ..........................................................................370
8.5.2 Simple Network Management Protocol (SNMP) ...................................................................370
8.6 MULTIMEDIA APPLICATION PROTOCOLS ....................................................................................372
8.6.1 Session Description Protocol (SDP) ......................................................................................372
8.6.2 Session Initiation Protocol (SIP) ...........................................................................................372
8.7 SUMMARY AND BIBLIOGRAPHICAL NOTES .................................................................................373
PROBLEMS ...............................................................................................................................................375
CHAPTER 9 TECHNOLOGIES AND FUTURE TRENDS ..........................................................376
9.1 NETWORK TECHNOLOGIES .........................................................................................................376
9.1.1 Mobile Wi-Fi .........................................................................................................................376
9.1.2 Wireless Broadband ..............................................................................................................377
9.1.3 Ethernet .................................................................................................................................378
9.1.4 Routers and Switches .............................................................................................................379
9.2 MULTIMEDIA COMMUNICATIONS ...............................................................................................379
9.2.1 Internet Telephony and VoIP .................................................................................................379
9.2.2 Unified Communications .......................................................................................................382
9.2.3 Wireless Multimedia ..............................................................................................................382
9.2.4 Videoconferencing .................................................................................................................383
9.2.5 Augmented Reality .................................................................................................................383
9.3 THE INTERNET OF THINGS ..........................................................................................................384
9.3.1 Smart Grid .............................................................................................................................384
9.3.2 The Web of Things .................................................................................................................388
9.4 CLOUD COMPUTING ....................................................................................................................388
9.5 NETWORK NEUTRALITY VS. TIERED SERVICES ...........................................................................390
9.6 SUMMARY AND BIBLIOGRAPHICAL NOTES .................................................................................391
PROGRAMMING ASSIGNMENTS .......................................................................................................393
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SOLUTIONS TO SELECTED PROBLEMS..........................................................................................401
APPENDIX A: PROBABILITY REFRESHER .....................................................................................471
REFERENCES ..........................................................................................................................................483
ACRONYMS AND ABBREVIATIONS ..................................................................................................491
INDEX ........................................................................................................................................................494