Network Performance Open Source Toolkit Using Netperf, tcptrace, NIST Net, and SSFNet

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2 Network Performance Open Source Toolkit Using Netperf, tcptrace, NIST Net, and SSFNet Richard Blum

3 Executive Publisher: Robert Ipsen Executive Editor: Carol Long Assistant Developmental Editor: Adaobi Obi Tulton Editorial Manager: Kathryn Malm Managing Editor: Pamela M. Hanley Text Design & Composition: Wiley Composition Services This book is printed on acid-free paper. Copyright 2003 by Richard Blum. All rights reserved. Published by Wiley Publishing, Inc., Indianapolis, Indiana Published simultaneously in Canada No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) , fax (978) Requests to the Publisher for permission should be addressed to the Legal Department, Wiley Publishing, Inc., Crosspoint Blvd., Indianapolis, IN 46256, (317) , fax (317) , permcoordinator@wiley.com. Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. For general information on our other products and services please contact our Customer Care Department within the United States at (800) , outside the United States at (317) or fax (317) Trademarks: Wiley, the Wiley Publishing logo, and related trade dress are trademarks or registered trademarks of Wiley Publishing, Inc., in the United States and other countries, and may not be used without written permission. All other trademarks are the property of their respective owners. Wiley Publishing, Inc., is not associated with any product or vendor mentioned in this book. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Library of Congress Cataloging-in-Publication Data: ISBN: Printed in the United States of America

4 This book is dedicated to my grandmother, Margaret Gordon. Sorry, grandma, it s not a mystery novel but then again, in a way, maybe it is. Trust in the Lord with all your heart and lean not on your own understanding; in all your ways acknowledge him, and he will make your paths straight. Prov. 3:5-6 (NIV)

6 Contents Acknowledgments xvii Introduction xix Part One Network Performance Primer 1 Chapter 1 Defining Network Performance 3 The Elements of Network Performance 4 Availability 4 Using Availability Statistics 5 Using Large Ping Packets 7 Response Time 8 Response-Time Factors 9 Determining Response Time from Ping Packets 9 Using traceroute for Redundant Paths 10 Network Utilization 11 Network Throughput 12 Bandwidth Capacity 14 Methods of Collecting Performance Data 15 Querying Network Devices 16 How Tools Query Devices 16 Values to Query 17 Watching Existing Traffic 18 Generating Test Traffic 19 Summary 20 Chapter 2 Watching Network Traffic 21 Catching All the Traffic 21 The libpcap Library 22 Downloading and Installing libpcap 22 Using libpcap 23 v

7 vi Contents The winpcap Library 24 Downloading and Installing winpcap 24 Developing Applications with winpcap 25 Using winpcap 25 The tcpdump Program 25 Installing tcpdump 26 Linux RPM Installation 26 Downloading the Source Code 27 Using tcpdump 27 The WinDump Program 31 Downloading and Installing WinDump 31 Using WinDump 31 Filtering Packets with tcpdump and WinDump 33 The Analyzer Program 35 The Ethereal Program 37 Downloading and Installing Ethereal 38 Using Ethereal 38 Summary 40 Chapter 3 Network Device Utilization 41 The net-snmp Package 41 Downloading and Installing net-snmp 42 Using net-snmp Utilities 44 snmpget 45 snmpgetnext 46 snmpwalk 47 snmpdelta 48 Standard Network Performance MIBs 49 Data Rates 49 Error Rates 51 Using Vendor MIBs 52 The CISCO CPU MIB 53 Using the Cisco CPU MIB 55 Summary 57 Part Two Network Performance Tools 59 Chapter 4 netperf 61 What Is netperf? 61 TCP Network Performance 62 UDP Network Performance 62 Downloading and Installing netperf 63 Downloading netperf 63 Installing the netperf Package 63 Running netserver 65 Using netserver in Standalone Mode 66 Autostarting netserver 67 netperf Command-Line Options 68

8 Contents vii Measuring Bulk Network Traffic 70 TCP_STREAM 70 UDP_STREAM 71 Measuring Request/Response Times 72 TCP_RR 73 TCP_CRR 75 UDP_RR 75 Using netperf Scripts 76 Summary 77 Chapter 5 dbs 79 dbs Features 79 The Components of dbs 80 The dbs Output 80 Before Installing dbs 81 The ntp Program 81 The gnuplot Program 82 Downloading and Installing dbs 82 Running the dbsd Program 84 Configuring Command Files 86 Sender and Receiver Commands 87 The Pattern Command 88 Sample Sender and Receiver Sections 89 Test Commands 90 Performing Tests 90 Define the Test Environment 91 Create the Command File 91 Run the Test 93 Analyze the Data 94 Summary 97 Chapter 6 Iperf 99 Iperf Features 99 The Components of Iperf 100 The Iperf Program 100 The jperf Front End 100 The Iperf library 101 Iperf Tests 101 Iperf Output 102 Downloading and Installing Iperf 103 Downloading the Source Code 104 Compiling the Source Code 104 Installing iperf 104 Using Iperf 105 Starting the Iperf Server 105 Standalone Mode 105 Daemon mode 106

9 viii Contents Performing Simple Tests 106 Testing TOS Traffic 108 Testing UDP Traffic 109 Testing Multicast Traffic 111 Testing a File Transfer 112 Testing TCP Window Sizes 113 Using jperf 114 Summary 115 Chapter 7 Pathrate 117 Using Statistics to Measure Bandwidth 118 How Pathrate Works 118 Initial Phase 118 Phase I 118 Phase II 119 How Pathload Works 119 Using Pathrate 120 The Pathrate Programs 120 Downloading Pathrate 121 Compiling Pathrate 121 Starting the Pathrate Server 122 Starting the Pathrate Client 122 Pathrate Test Output 123 Quick Termination Mode 123 Full Testing Mode 124 Initial Phase Results 125 Phase I Results 125 Phase II Results 126 Using Pathload 127 Pathload 127 Downloading and Configuring Pathload 127 Starting the Pathload Server 128 Starting the Pathload Client 128 Pathload Output 129 Requested Fleet Parameters 129 Loss Rate per Stream 130 Server Fleet Parameters 130 Context Switches 131 Packet Discards 131 Relative One-Way Packet Delay Trend 131 Fleet Aggregate Trend 132 State Variable Updated 133 Final Test Results 133 Summary 134

10 Contents ix Chapter 8 Nettest 137 What Is Nettest? 137 The lblnettest Application 138 Certificates and Keys 139 The ACLFile File 139 Test Applications 139 The OpenSSL Package 140 Downloading and Installing Nettest 142 Downloading Nettest 142 Before Compiling 143 Define All Test Hosts 143 Modify the Source Code 144 Compiling and Installing Nettest 145 Creating Certificates and Keys 146 Creating a Certificate Authority 147 Creating the Client Certificate and Key 148 Creating the Server Certificate and Key 149 Creating the ACLFile File 149 Using Nettest 150 Starting a Nettest Session 151 Performing Tests 152 Summary 154 Chapter 9 NetLogger 155 What Is NetLogger? 156 NetLogger APIs 156 NetLogger Host and Network Monitoring Tools 156 NetLogger Log File 157 NetLogger Graphical Tool 158 Downloading and Installing NetLogger 158 Source Code Distribution File 158 Binary Distribution File 160 Using the APIs 160 Functions 160 Open 160 Write 162 Close 163 Libraries 164 Using nlv 165 Types of nlv graphs 165 Configuring nlv 167 The bltgraph.pro File 167 The nlv-main.cfg File 167 The nlv-keys.cfg File 169 Summary 173

11 x Contents Chapter 10 tcptrace 175 What Is tcptrace? 175 Console Mode 176 Graphical Mode 177 Downloading and Installing tcptrace 178 Using tcptrace in Console Mode 179 Using Basic Command-Line Options 179 Standard Session Output 179 tcptrace Filters 183 Using Module Options 185 Graphical Programs 187 xplot 187 jplot 188 Using tcptrace in Graphical Mode 189 Standard Graphs 189 Throughput Graph 189 Time Sequence Graph 191 Traffic Module Graphs 193 Summary 194 Chapter 11 ntop 197 What Is ntop? 198 Traffic Measuring 198 Data Received 198 Data Sent 199 Network Throughput 199 Traffic Monitoring 200 Statistics 200 IP Traffic 201 IP Protocols 201 Before Installing ntop 202 Creating the ntop User ID 203 Loading Support Software 203 Downloading and Installing ntop 204 Compiling and Installing gdchart 205 Compiling ntop 206 Running ntop 206 Starting ntop for the First Time 207 ntop Command-Line Parameters 208 Using ntop Command-Line Parameters 209 Monitoring Network Traffic 209 Analyzing a tcpdump Dump File 210 ntop Access Log File 211 Viewing ntop Data 211 Connecting to ntop 211 Watching Hosts 212 Watching Network Traffic 214 Summary 215

12 Contents xi Chapter 12 Comparing Network Performance Tools 217 Tools for Testing the Network 218 Bulk Data Transfers 218 Using Pathrate to Find the Network Bottleneck 219 Using netperf to See Actual Network Bandwidth 221 Using ntop to Analyze Network Traffic 223 Using NetLogger to Analyze Host Functions 225 Request/Response Traffic 225 Using netperf to Simulate HTTP Traffic 227 Using tcptrace to Watch HTTP Sessions 228 Analyzing Production Traffic 229 Analyzing an FTP Session 230 Using tcptrace 230 Using ntop 233 Analyzing a Telnet Session 234 Using tcptrace 235 Using ntop 237 Summary 237 Part Three Application Performance Tools 239 Chapter 13 Measuring Application Performance 241 Methods of Testing Network Applications 242 The Test Network 242 Production Network 243 Network Emulation 243 Network Traffic Generator 244 Network Emulation Device 244 Network Simulation 245 Discrete Event 246 Analytical 246 Modeling Network Problems 246 Bandwidth Constraints 247 Packet Errors 248 Lost Packets 248 Out-of-Order Packets 249 Delayed Packets 250 Modeling Network Devices 251 Hubs 251 Switches 252 Routers 253 Quality of Service 254 Weighted Fair Queuing 254 Stochastic Fair Queuing 254 Random Early Detection 255 Firewalls 255

13 xii Contents Wide Area Networks 256 Modeling Point-to-Point Networks 256 Modeling Packet-Switching Networks 257 Wireless Networks 257 Summary 258 Chapter 14 dummynet 259 What Is dummynet? 260 Dummynet Features 260 Using the dummynet Host 261 The ipfw Application 263 Creating New Rules 264 Rule Number 264 Rule Probability 265 Rule Action 265 Rule Logging 266 Rule Definition 266 Listing Rules 266 Removing Rules 267 dummynet Rules 268 dummynet Commands 268 Bandwidth 269 Delay 269 Random Packet Loss 270 Queue Size 270 Configuring WFQ 271 Configuring Multipath Links 271 Installing dummynet 271 Kernel Options 272 Building a New Kernel 273 Installing PicoBSD 273 Controlling dummynet 274 Testing dummynet 275 Setting Network Delays 275 Setting Network Bandwidths 277 Summary 277 Chapter 15 NIST Net 279 What Is NIST Net? 279 NIST Net Emulations 280 Bandwidth Limitation 280 Packet Delay 281 Packet Reordering 281 Packet Loss 281 Packet Duplication 282 Packet Diversion 282 The NIST Net Kernel Module 282

14 Contents xiii The NIST Net Configuration Tools 285 The NIST Net Optional Tools 286 mungebox 287 nistspy 287 Downloading and Installing NIST Net 288 Downloading NIST Net 288 Compiling NIST Net 288 Getting the Required Files 289 Compiling the Source Code 290 Loading NIST Net 291 Using NIST Net 292 Using cnistnet 292 Using xnistnet 295 Creating Rules 296 Modifying Rules 297 Summary 298 Chapter 16 Network Traffic Generator 301 What Is Network Traffic Generator? 301 How Network Traffic Generator Works 302 The Core Modules 302 The Protocol Modules 303 The Payload Modules 303 The Response Modules 304 The Network Traffic Generator Programs 304 Command-Line Interface 304 X Windows Interface 305 Generating Network Traffic 306 Bulk Data Transfers 306 Client/Server Transactions 307 Connectionless Communication 308 Downloading and Installing the Package 308 Downloading 308 Before Compiling 309 fastdep 309 Kylix Libraries 310 Compiling and Installing 311 Using Network Traffic Generator 312 Command-Line Options 312 Server 312 Client 313 Setting Up a Test 315 Test Host Placement 316 Test Host Configuration 316 Watching the Test Traffic 317 Summary 320

15 xiv Contents Chapter 17 ns 321 What Is ns? 321 Network Simulator Programs 322 ns 322 nam 323 xgraph 324 Network Model Elements 324 Network Nodes 324 Network Links 325 Network Agents 326 Network Applications 327 ns Modeling Language 329 Downloading and Installing ns 330 Downloading 331 Compiling and Installing 332 Validating the Installation 332 Performing a Network Simulation 332 Creating the Simulation Model 333 Running the Simulation 336 Using nam 338 Using xgraph 339 Summary 340 Chapter 18 SSFNet 343 What Is SSF? 344 Entities 344 Processes 344 Events 345 In Channels 345 Out Channels 345 What Is SSFNet? 345 Libraries 345 Domain Modeling Language (DML) 346 Networks 347 Hosts 349 Links 350 Routers 351 Protocols 352 Downloading and Installing SSFNet 353 Downloading 354 Installing 354 Creating a Development Environment 355 Using SSFNet 356 Creating a Model 356 Running the Simulation 360 Interpreting the Results 362 Summary 364

16 Contents xv Chapter 19 Comparing Application Performance Tools 365 Modeling the Production Environment 365 The Production Network 366 Modeling the Network 367 Using ns 368 Building the Model 368 Running the Model 371 Interpreting the Results 372 Using SSFNet 374 Building the Model 374 Running the Model 377 Interpreting the Results 379 Using dummynet 379 Building the Emulation Environment 379 Running the Emulation 380 Using NIST Net 381 Building the Emulation Environment 381 Running the Emulation 383 Final Results 383 Summary 384 Appendix Resources 387 Index 391

18 Acknowledgments First, all glory, honor, and praise go to God, who through His Son makes all things possible, and who gives us the gift of eternal life. I would like to thank all the great people at Wiley Publishing, Inc. for their help, guidance, and professionalism. Thanks to Carol Long, the Acquisitions Editor, for offering me the opportunity to write this book, and to Adaobi Obi Tulton, the Assistant Developmental Editor, for both helping guide this book along, and working to help make the paragraphs make sense. Also many thanks to Carole McClendon at Waterside Productions for her help in arranging this opportunity for me. Finally, I would like to thank my parents, Mike and Joyce Blum, for their dedication and support, and my wife Barbara and daughters Katie Jane and Jessica for their faith, love, and understanding, especially while I was writing this book. xvii

20 Introduction The job of the network administrator is complicated. If you are a network administrator, not only are you responsible for installing and maintaining the wires, hubs, switches, and possibly routers and firewalls, but you must also ensure that they all work efficiently together. Of course, this all must be done within the constraints of a budget, which these days is often smaller than what you really need to accomplish the job. The goal of this book is to show you some freely available tools that can be used to help monitor and troubleshoot a network, providing you with a toolkit of programs to use when problems arise. The network administrator is often the first line of defense whenever anything behaves oddly on the network. Even when there is no clear-cut culprit, the network administrator has to prove that the network is not at fault. Network performance is often a difficult thing to measure. What is fast performance for one application can often be slow for another. It is your job to ensure that the network and the network applications are performing properly for your environment. This book is intended to help you with this task. Overview Network performance has been studied for many years, which has produced lots of theoretical work on how network traffic is affected by network load. Unfortunately, for the average network administrator in charge of the company network, equations and theories do not help solve real-world problems, such as slow network application performance. Instead, what is required is xix

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